add other session providers (#5963)

160 files changed, 37644 insertions, 66 deletions

diff --git a/Gopkg.lock b/Gopkg.lock
index 65cdf7efa3..ba21eca95c 100644
--- a/Gopkg.lock
+++ b/Gopkg.lock
@@ -18,6 +18,14 @@
   revision = "d5a42771e7e851e8a89c5c6ffa0f5b075342f9df"
 
 [[projects]]
+  digest = "1:5d72bbcc9c8667b11c3dc3cbe681c5a6f71e5096744c0bf7726ab5c6425d5dc4"
+  name = "github.com/BurntSushi/toml"
+  packages = ["."]
+  pruneopts = "NUT"
+  revision = "3012a1dbe2e4bd1391d42b32f0577cb7bbc7f005"
+  version = "v0.3.1"
+
+[[projects]]
   digest = "1:3fcef06a1a6561955c94af6c7757a6fa37605eb653f0d06ab960e5bb80092195"
   name = "github.com/PuerkitoBio/goquery"
   packages = ["."]
@@ -187,6 +195,28 @@
 
 [[projects]]
   branch = "master"
+  digest = "1:eb205556fe75307c6d2b58d4159e7c2da23e2666481d352c66d4055bebf45a3c"
+  name = "github.com/couchbase/gomemcached"
+  packages = [
+    ".",
+    "client",
+  ]
+  pruneopts = "NUT"
+  revision = "5125a94a666c83cb9b7a60907833cd320b84c20f"
+
+[[projects]]
+  branch = "master"
+  digest = "1:ea03e12e246f7708a7b7ab3ad04e96d21ce73f48bb56258bc2bffeed474212e6"
+  name = "github.com/couchbase/goutils"
+  packages = [
+    "logging",
+    "scramsha",
+  ]
+  pruneopts = "NUT"
+  revision = "e865a1461c8ac0032bd37e2d4dab3289faea3873"
+
+[[projects]]
+  branch = "master"
   digest = "1:82e1ad11d777f7bff9a1fc678a8a534a318f85e5026a8a4d6f4a94a6b0678bb6"
   name = "github.com/couchbase/vellum"
   packages = [
@@ -198,6 +228,14 @@
   revision = "eb6ae3743b3f300f2136f83ca78c08cc071edbd4"
 
 [[projects]]
+  branch = "master"
+  digest = "1:df592f4b82b993fcac270862376c34210776b8b0334a0f59f4d9d80467713ffa"
+  name = "github.com/couchbaselabs/go-couchbase"
+  packages = ["."]
+  pruneopts = "NUT"
+  revision = "d904413d884d1fb849e2ad8834619f661761ef57"
+
+[[projects]]
   digest = "1:a2c1d0e43bd3baaa071d1b9ed72c27d78169b2b269f71c105ac4ba34b1be4a39"
   name = "github.com/davecgh/go-spew"
   packages = ["spew"]
@@ -358,14 +396,19 @@
 
 [[projects]]
   branch = "master"
-  digest = "1:8fea5718d84af17762195beb6fe92a0d6c1048452a1dbc464d227f12e0cff0cc"
+  digest = "1:a26b7b56aece087165b8db87afb05db8495252449553ca20d15f5a24202f36bc"
   name = "github.com/go-macaron/session"
   packages = [
     ".",
+    "couchbase",
+    "memcache",
+    "mysql",
+    "nodb",
+    "postgres",
     "redis",
   ]
   pruneopts = "NUT"
-  revision = "330e4e4d8beb7b00111ac34539561f46f94c4458"
+  revision = "0a0a789bf1934e55fde19629869caa015a40c525"
 
 [[projects]]
   digest = "1:758d2371fcdee6d02565901b348729053c636055e67ef6e17aa466c7ff6cc57c"
@@ -580,6 +623,28 @@
   revision = "e3534c89ef969912856dfa39e56b09e58c5f5daf"
 
 [[projects]]
+  digest = "1:1e6a29ed1f189354030e3371f63ec58aacbc2bf232fd104c6e0d41174ac5af48"
+  name = "github.com/lunny/log"
+  packages = ["."]
+  pruneopts = "NUT"
+  revision = "7887c61bf0de75586961948b286be6f7d05d9f58"
+  version = "v0.1"
+
+[[projects]]
+  branch = "master"
+  digest = "1:683d835728cb95d176d423b522420eb5e4ec859b276bca18466476b82b3ebc4c"
+  name = "github.com/lunny/nodb"
+  packages = [
+    ".",
+    "config",
+    "store",
+    "store/driver",
+    "store/goleveldb",
+  ]
+  pruneopts = "NUT"
+  revision = "fc1ef06ad4af0da31cdb87e3fa5ec084c67e6597"
+
+[[projects]]
   digest = "1:aa7dcd6a0db70d514821f8739d0a22e7df33b499d8d399cf15b2858d44f8319e"
   name = "github.com/markbates/goth"
   packages = [
@@ -683,6 +748,14 @@
   version = "v1.0.0"
 
 [[projects]]
+  digest = "1:14715f705ff5dfe0ffd6571d7d201dd8e921030f8070321a79380d8ca4ec1a24"
+  name = "github.com/pkg/errors"
+  packages = ["."]
+  pruneopts = "NUT"
+  revision = "ba968bfe8b2f7e042a574c888954fccecfa385b4"
+  version = "v0.8.1"
+
+[[projects]]
   digest = "1:0028cb19b2e4c3112225cd871870f2d9cf49b9b4276531f03438a88e94be86fe"
   name = "github.com/pmezard/go-difflib"
   packages = ["difflib"]
@@ -776,6 +849,14 @@
   revision = "1dba4b3954bc059efc3991ec364f9f9a35f597d2"
 
 [[projects]]
+  branch = "master"
+  digest = "1:dbda803f21e60c38de7d9f884390f2ebbe234ce0c3d139b65bbb36b03a99d266"
+  name = "github.com/siddontang/go-snappy"
+  packages = ["snappy"]
+  pruneopts = "NUT"
+  revision = "d8f7bb82a96d89c1254e5a6c967134e1433c9ee2"
+
+[[projects]]
   digest = "1:89fd77d603a74a6540d60067debad9397865bf040955d907362c95d364baeba6"
   name = "github.com/src-d/gcfg"
   packages = [
@@ -806,6 +887,27 @@
 
 [[projects]]
   branch = "master"
+  digest = "1:685fdfea42d825ebd39ee0994354b46c374cf2c2b2d97a41a8dee1807c6a9b62"
+  name = "github.com/syndtr/goleveldb"
+  packages = [
+    "leveldb",
+    "leveldb/cache",
+    "leveldb/comparer",
+    "leveldb/errors",
+    "leveldb/filter",
+    "leveldb/iterator",
+    "leveldb/journal",
+    "leveldb/memdb",
+    "leveldb/opt",
+    "leveldb/storage",
+    "leveldb/table",
+    "leveldb/util",
+  ]
+  pruneopts = "NUT"
+  revision = "2f17a3356c6616cbfc4ae4c38147dc062a68fb0e"
+
+[[projects]]
+  branch = "master"
   digest = "1:3cb6dfe7cdece5716b1c3c3c0b5faf7fce2e83e2758e2baad2e9986d101980b8"
   name = "github.com/tinylib/msgp"
   packages = ["msgp"]
@@ -1150,6 +1252,11 @@
     "github.com/go-macaron/i18n",
     "github.com/go-macaron/inject",
     "github.com/go-macaron/session",
+    "github.com/go-macaron/session/couchbase",
+    "github.com/go-macaron/session/memcache",
+    "github.com/go-macaron/session/mysql",
+    "github.com/go-macaron/session/nodb",
+    "github.com/go-macaron/session/postgres",
     "github.com/go-macaron/session/redis",
     "github.com/go-macaron/toolbox",
     "github.com/go-sql-driver/mysql",
diff --git a/docs/content/doc/advanced/config-cheat-sheet.en-us.md b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
index c2d22f1d83..8254316716 100644
--- a/docs/content/doc/advanced/config-cheat-sheet.en-us.md
+++ b/docs/content/doc/advanced/config-cheat-sheet.en-us.md
@@ -250,7 +250,7 @@ Values containing `#` or `;` must be quoted using `` ` `` or `"""`.
 
 ## Session (`session`)
 
-- `PROVIDER`: **memory**: Session engine provider \[memory, file, redis, mysql\].
+- `PROVIDER`: **memory**: Session engine provider \[memory, file, redis, mysql, couchbase, memcache, nodb, postgres\].
 - `PROVIDER_CONFIG`: **data/sessions**: For file, the root path; for others, the connection string.
 - `COOKIE_SECURE`: **false**: Enable this to force using HTTPS for all session access.
 - `COOKIE_NAME`: **i\_like\_gitea**: The name of the cookie used for the session ID.
diff --git a/modules/setting/setting.go b/modules/setting/setting.go
index a2fdbf5192..77f0725d00 100644
--- a/modules/setting/setting.go
+++ b/modules/setting/setting.go
@@ -31,7 +31,12 @@ import (
 	_ "github.com/go-macaron/cache/memcache" // memcache plugin for cache
 	_ "github.com/go-macaron/cache/redis"
 	"github.com/go-macaron/session"
-	_ "github.com/go-macaron/session/redis" // redis plugin for store session
+	_ "github.com/go-macaron/session/couchbase" // couchbase plugin for session store
+	_ "github.com/go-macaron/session/memcache"  // memcache plugin for session store
+	_ "github.com/go-macaron/session/mysql"     // mysql plugin for session store
+	_ "github.com/go-macaron/session/nodb"      // nodb plugin for session store
+	_ "github.com/go-macaron/session/postgres"  // postgres plugin for session store
+	_ "github.com/go-macaron/session/redis"     // redis plugin for store session
 	"github.com/go-xorm/core"
 	shellquote "github.com/kballard/go-shellquote"
 	version "github.com/mcuadros/go-version"
@@ -1506,7 +1511,7 @@ func newCacheService() {
 
 func newSessionService() {
 	SessionConfig.Provider = Cfg.Section("session").Key("PROVIDER").In("memory",
-		[]string{"memory", "file", "redis", "mysql"})
+		[]string{"memory", "file", "redis", "mysql", "postgres", "couchbase", "memcache", "nodb"})
 	SessionConfig.ProviderConfig = strings.Trim(Cfg.Section("session").Key("PROVIDER_CONFIG").MustString(path.Join(AppDataPath, "sessions")), "\" ")
 	if SessionConfig.Provider == "file" && !filepath.IsAbs(SessionConfig.ProviderConfig) {
 		SessionConfig.ProviderConfig = path.Join(AppWorkPath, SessionConfig.ProviderConfig)
diff --git a/vendor/github.com/BurntSushi/toml/COPYING b/vendor/github.com/BurntSushi/toml/COPYING
new file mode 100644
index 0000000000..01b5743200
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/COPYING
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 TOML authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/vendor/github.com/BurntSushi/toml/cmd/toml-test-decoder/COPYING b/vendor/github.com/BurntSushi/toml/cmd/toml-test-decoder/COPYING
new file mode 100644
index 0000000000..01b5743200
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/cmd/toml-test-decoder/COPYING
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 TOML authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/vendor/github.com/BurntSushi/toml/cmd/toml-test-encoder/COPYING b/vendor/github.com/BurntSushi/toml/cmd/toml-test-encoder/COPYING
new file mode 100644
index 0000000000..01b5743200
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/cmd/toml-test-encoder/COPYING
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 TOML authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/vendor/github.com/BurntSushi/toml/cmd/tomlv/COPYING b/vendor/github.com/BurntSushi/toml/cmd/tomlv/COPYING
new file mode 100644
index 0000000000..01b5743200
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/cmd/tomlv/COPYING
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2013 TOML authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/vendor/github.com/BurntSushi/toml/decode.go b/vendor/github.com/BurntSushi/toml/decode.go
new file mode 100644
index 0000000000..b0fd51d5b6
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/decode.go
@@ -0,0 +1,509 @@
+package toml
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math"
+	"reflect"
+	"strings"
+	"time"
+)
+
+func e(format string, args ...interface{}) error {
+	return fmt.Errorf("toml: "+format, args...)
+}
+
+// Unmarshaler is the interface implemented by objects that can unmarshal a
+// TOML description of themselves.
+type Unmarshaler interface {
+	UnmarshalTOML(interface{}) error
+}
+
+// Unmarshal decodes the contents of `p` in TOML format into a pointer `v`.
+func Unmarshal(p []byte, v interface{}) error {
+	_, err := Decode(string(p), v)
+	return err
+}
+
+// Primitive is a TOML value that hasn't been decoded into a Go value.
+// When using the various `Decode*` functions, the type `Primitive` may
+// be given to any value, and its decoding will be delayed.
+//
+// A `Primitive` value can be decoded using the `PrimitiveDecode` function.
+//
+// The underlying representation of a `Primitive` value is subject to change.
+// Do not rely on it.
+//
+// N.B. Primitive values are still parsed, so using them will only avoid
+// the overhead of reflection. They can be useful when you don't know the
+// exact type of TOML data until run time.
+type Primitive struct {
+	undecoded interface{}
+	context   Key
+}
+
+// DEPRECATED!
+//
+// Use MetaData.PrimitiveDecode instead.
+func PrimitiveDecode(primValue Primitive, v interface{}) error {
+	md := MetaData{decoded: make(map[string]bool)}
+	return md.unify(primValue.undecoded, rvalue(v))
+}
+
+// PrimitiveDecode is just like the other `Decode*` functions, except it
+// decodes a TOML value that has already been parsed. Valid primitive values
+// can *only* be obtained from values filled by the decoder functions,
+// including this method. (i.e., `v` may contain more `Primitive`
+// values.)
+//
+// Meta data for primitive values is included in the meta data returned by
+// the `Decode*` functions with one exception: keys returned by the Undecoded
+// method will only reflect keys that were decoded. Namely, any keys hidden
+// behind a Primitive will be considered undecoded. Executing this method will
+// update the undecoded keys in the meta data. (See the example.)
+func (md *MetaData) PrimitiveDecode(primValue Primitive, v interface{}) error {
+	md.context = primValue.context
+	defer func() { md.context = nil }()
+	return md.unify(primValue.undecoded, rvalue(v))
+}
+
+// Decode will decode the contents of `data` in TOML format into a pointer
+// `v`.
+//
+// TOML hashes correspond to Go structs or maps. (Dealer's choice. They can be
+// used interchangeably.)
+//
+// TOML arrays of tables correspond to either a slice of structs or a slice
+// of maps.
+//
+// TOML datetimes correspond to Go `time.Time` values.
+//
+// All other TOML types (float, string, int, bool and array) correspond
+// to the obvious Go types.
+//
+// An exception to the above rules is if a type implements the
+// encoding.TextUnmarshaler interface. In this case, any primitive TOML value
+// (floats, strings, integers, booleans and datetimes) will be converted to
+// a byte string and given to the value's UnmarshalText method. See the
+// Unmarshaler example for a demonstration with time duration strings.
+//
+// Key mapping
+//
+// TOML keys can map to either keys in a Go map or field names in a Go
+// struct. The special `toml` struct tag may be used to map TOML keys to
+// struct fields that don't match the key name exactly. (See the example.)
+// A case insensitive match to struct names will be tried if an exact match
+// can't be found.
+//
+// The mapping between TOML values and Go values is loose. That is, there
+// may exist TOML values that cannot be placed into your representation, and
+// there may be parts of your representation that do not correspond to
+// TOML values. This loose mapping can be made stricter by using the IsDefined
+// and/or Undecoded methods on the MetaData returned.
+//
+// This decoder will not handle cyclic types. If a cyclic type is passed,
+// `Decode` will not terminate.
+func Decode(data string, v interface{}) (MetaData, error) {
+	rv := reflect.ValueOf(v)
+	if rv.Kind() != reflect.Ptr {
+		return MetaData{}, e("Decode of non-pointer %s", reflect.TypeOf(v))
+	}
+	if rv.IsNil() {
+		return MetaData{}, e("Decode of nil %s", reflect.TypeOf(v))
+	}
+	p, err := parse(data)
+	if err != nil {
+		return MetaData{}, err
+	}
+	md := MetaData{
+		p.mapping, p.types, p.ordered,
+		make(map[string]bool, len(p.ordered)), nil,
+	}
+	return md, md.unify(p.mapping, indirect(rv))
+}
+
+// DecodeFile is just like Decode, except it will automatically read the
+// contents of the file at `fpath` and decode it for you.
+func DecodeFile(fpath string, v interface{}) (MetaData, error) {
+	bs, err := ioutil.ReadFile(fpath)
+	if err != nil {
+		return MetaData{}, err
+	}
+	return Decode(string(bs), v)
+}
+
+// DecodeReader is just like Decode, except it will consume all bytes
+// from the reader and decode it for you.
+func DecodeReader(r io.Reader, v interface{}) (MetaData, error) {
+	bs, err := ioutil.ReadAll(r)
+	if err != nil {
+		return MetaData{}, err
+	}
+	return Decode(string(bs), v)
+}
+
+// unify performs a sort of type unification based on the structure of `rv`,
+// which is the client representation.
+//
+// Any type mismatch produces an error. Finding a type that we don't know
+// how to handle produces an unsupported type error.
+func (md *MetaData) unify(data interface{}, rv reflect.Value) error {
+
+	// Special case. Look for a `Primitive` value.
+	if rv.Type() == reflect.TypeOf((*Primitive)(nil)).Elem() {
+		// Save the undecoded data and the key context into the primitive
+		// value.
+		context := make(Key, len(md.context))
+		copy(context, md.context)
+		rv.Set(reflect.ValueOf(Primitive{
+			undecoded: data,
+			context:   context,
+		}))
+		return nil
+	}
+
+	// Special case. Unmarshaler Interface support.
+	if rv.CanAddr() {
+		if v, ok := rv.Addr().Interface().(Unmarshaler); ok {
+			return v.UnmarshalTOML(data)
+		}
+	}
+
+	// Special case. Handle time.Time values specifically.
+	// TODO: Remove this code when we decide to drop support for Go 1.1.
+	// This isn't necessary in Go 1.2 because time.Time satisfies the encoding
+	// interfaces.
+	if rv.Type().AssignableTo(rvalue(time.Time{}).Type()) {
+		return md.unifyDatetime(data, rv)
+	}
+
+	// Special case. Look for a value satisfying the TextUnmarshaler interface.
+	if v, ok := rv.Interface().(TextUnmarshaler); ok {
+		return md.unifyText(data, v)
+	}
+	// BUG(burntsushi)
+	// The behavior here is incorrect whenever a Go type satisfies the
+	// encoding.TextUnmarshaler interface but also corresponds to a TOML
+	// hash or array. In particular, the unmarshaler should only be applied
+	// to primitive TOML values. But at this point, it will be applied to
+	// all kinds of values and produce an incorrect error whenever those values
+	// are hashes or arrays (including arrays of tables).
+
+	k := rv.Kind()
+
+	// laziness
+	if k >= reflect.Int && k <= reflect.Uint64 {
+		return md.unifyInt(data, rv)
+	}
+	switch k {
+	case reflect.Ptr:
+		elem := reflect.New(rv.Type().Elem())
+		err := md.unify(data, reflect.Indirect(elem))
+		if err != nil {
+			return err
+		}
+		rv.Set(elem)
+		return nil
+	case reflect.Struct:
+		return md.unifyStruct(data, rv)
+	case reflect.Map:
+		return md.unifyMap(data, rv)
+	case reflect.Array:
+		return md.unifyArray(data, rv)
+	case reflect.Slice:
+		return md.unifySlice(data, rv)
+	case reflect.String:
+		return md.unifyString(data, rv)
+	case reflect.Bool:
+		return md.unifyBool(data, rv)
+	case reflect.Interface:
+		// we only support empty interfaces.
+		if rv.NumMethod() > 0 {
+			return e("unsupported type %s", rv.Type())
+		}
+		return md.unifyAnything(data, rv)
+	case reflect.Float32:
+		fallthrough
+	case reflect.Float64:
+		return md.unifyFloat64(data, rv)
+	}
+	return e("unsupported type %s", rv.Kind())
+}
+
+func (md *MetaData) unifyStruct(mapping interface{}, rv reflect.Value) error {
+	tmap, ok := mapping.(map[string]interface{})
+	if !ok {
+		if mapping == nil {
+			return nil
+		}
+		return e("type mismatch for %s: expected table but found %T",
+			rv.Type().String(), mapping)
+	}
+
+	for key, datum := range tmap {
+		var f *field
+		fields := cachedTypeFields(rv.Type())
+		for i := range fields {
+			ff := &fields[i]
+			if ff.name == key {
+				f = ff
+				break
+			}
+			if f == nil && strings.EqualFold(ff.name, key) {
+				f = ff
+			}
+		}
+		if f != nil {
+			subv := rv
+			for _, i := range f.index {
+				subv = indirect(subv.Field(i))
+			}
+			if isUnifiable(subv) {
+				md.decoded[md.context.add(key).String()] = true
+				md.context = append(md.context, key)
+				if err := md.unify(datum, subv); err != nil {
+					return err
+				}
+				md.context = md.context[0 : len(md.context)-1]
+			} else if f.name != "" {
+				// Bad user! No soup for you!
+				return e("cannot write unexported field %s.%s",
+					rv.Type().String(), f.name)
+			}
+		}
+	}
+	return nil
+}
+
+func (md *MetaData) unifyMap(mapping interface{}, rv reflect.Value) error {
+	tmap, ok := mapping.(map[string]interface{})
+	if !ok {
+		if tmap == nil {
+			return nil
+		}
+		return badtype("map", mapping)
+	}
+	if rv.IsNil() {
+		rv.Set(reflect.MakeMap(rv.Type()))
+	}
+	for k, v := range tmap {
+		md.decoded[md.context.add(k).String()] = true
+		md.context = append(md.context, k)
+
+		rvkey := indirect(reflect.New(rv.Type().Key()))
+		rvval := reflect.Indirect(reflect.New(rv.Type().Elem()))
+		if err := md.unify(v, rvval); err != nil {
+			return err
+		}
+		md.context = md.context[0 : len(md.context)-1]
+
+		rvkey.SetString(k)
+		rv.SetMapIndex(rvkey, rvval)
+	}
+	return nil
+}
+
+func (md *MetaData) unifyArray(data interface{}, rv reflect.Value) error {
+	datav := reflect.ValueOf(data)
+	if datav.Kind() != reflect.Slice {
+		if !datav.IsValid() {
+			return nil
+		}
+		return badtype("slice", data)
+	}
+	sliceLen := datav.Len()
+	if sliceLen != rv.Len() {
+		return e("expected array length %d; got TOML array of length %d",
+			rv.Len(), sliceLen)
+	}
+	return md.unifySliceArray(datav, rv)
+}
+
+func (md *MetaData) unifySlice(data interface{}, rv reflect.Value) error {
+	datav := reflect.ValueOf(data)
+	if datav.Kind() != reflect.Slice {
+		if !datav.IsValid() {
+			return nil
+		}
+		return badtype("slice", data)
+	}
+	n := datav.Len()
+	if rv.IsNil() || rv.Cap() < n {
+		rv.Set(reflect.MakeSlice(rv.Type(), n, n))
+	}
+	rv.SetLen(n)
+	return md.unifySliceArray(datav, rv)
+}
+
+func (md *MetaData) unifySliceArray(data, rv reflect.Value) error {
+	sliceLen := data.Len()
+	for i := 0; i < sliceLen; i++ {
+		v := data.Index(i).Interface()
+		sliceval := indirect(rv.Index(i))
+		if err := md.unify(v, sliceval); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (md *MetaData) unifyDatetime(data interface{}, rv reflect.Value) error {
+	if _, ok := data.(time.Time); ok {
+		rv.Set(reflect.ValueOf(data))
+		return nil
+	}
+	return badtype("time.Time", data)
+}
+
+func (md *MetaData) unifyString(data interface{}, rv reflect.Value) error {
+	if s, ok := data.(string); ok {
+		rv.SetString(s)
+		return nil
+	}
+	return badtype("string", data)
+}
+
+func (md *MetaData) unifyFloat64(data interface{}, rv reflect.Value) error {
+	if num, ok := data.(float64); ok {
+		switch rv.Kind() {
+		case reflect.Float32:
+			fallthrough
+		case reflect.Float64:
+			rv.SetFloat(num)
+		default:
+			panic("bug")
+		}
+		return nil
+	}
+	return badtype("float", data)
+}
+
+func (md *MetaData) unifyInt(data interface{}, rv reflect.Value) error {
+	if num, ok := data.(int64); ok {
+		if rv.Kind() >= reflect.Int && rv.Kind() <= reflect.Int64 {
+			switch rv.Kind() {
+			case reflect.Int, reflect.Int64:
+				// No bounds checking necessary.
+			case reflect.Int8:
+				if num < math.MinInt8 || num > math.MaxInt8 {
+					return e("value %d is out of range for int8", num)
+				}
+			case reflect.Int16:
+				if num < math.MinInt16 || num > math.MaxInt16 {
+					return e("value %d is out of range for int16", num)
+				}
+			case reflect.Int32:
+				if num < math.MinInt32 || num > math.MaxInt32 {
+					return e("value %d is out of range for int32", num)
+				}
+			}
+			rv.SetInt(num)
+		} else if rv.Kind() >= reflect.Uint && rv.Kind() <= reflect.Uint64 {
+			unum := uint64(num)
+			switch rv.Kind() {
+			case reflect.Uint, reflect.Uint64:
+				// No bounds checking necessary.
+			case reflect.Uint8:
+				if num < 0 || unum > math.MaxUint8 {
+					return e("value %d is out of range for uint8", num)
+				}
+			case reflect.Uint16:
+				if num < 0 || unum > math.MaxUint16 {
+					return e("value %d is out of range for uint16", num)
+				}
+			case reflect.Uint32:
+				if num < 0 || unum > math.MaxUint32 {
+					return e("value %d is out of range for uint32", num)
+				}
+			}
+			rv.SetUint(unum)
+		} else {
+			panic("unreachable")
+		}
+		return nil
+	}
+	return badtype("integer", data)
+}
+
+func (md *MetaData) unifyBool(data interface{}, rv reflect.Value) error {
+	if b, ok := data.(bool); ok {
+		rv.SetBool(b)
+		return nil
+	}
+	return badtype("boolean", data)
+}
+
+func (md *MetaData) unifyAnything(data interface{}, rv reflect.Value) error {
+	rv.Set(reflect.ValueOf(data))
+	return nil
+}
+
+func (md *MetaData) unifyText(data interface{}, v TextUnmarshaler) error {
+	var s string
+	switch sdata := data.(type) {
+	case TextMarshaler:
+		text, err := sdata.MarshalText()
+		if err != nil {
+			return err
+		}
+		s = string(text)
+	case fmt.Stringer:
+		s = sdata.String()
+	case string:
+		s = sdata
+	case bool:
+		s = fmt.Sprintf("%v", sdata)
+	case int64:
+		s = fmt.Sprintf("%d", sdata)
+	case float64:
+		s = fmt.Sprintf("%f", sdata)
+	default:
+		return badtype("primitive (string-like)", data)
+	}
+	if err := v.UnmarshalText([]byte(s)); err != nil {
+		return err
+	}
+	return nil
+}
+
+// rvalue returns a reflect.Value of `v`. All pointers are resolved.
+func rvalue(v interface{}) reflect.Value {
+	return indirect(reflect.ValueOf(v))
+}
+
+// indirect returns the value pointed to by a pointer.
+// Pointers are followed until the value is not a pointer.
+// New values are allocated for each nil pointer.
+//
+// An exception to this rule is if the value satisfies an interface of
+// interest to us (like encoding.TextUnmarshaler).
+func indirect(v reflect.Value) reflect.Value {
+	if v.Kind() != reflect.Ptr {
+		if v.CanSet() {
+			pv := v.Addr()
+			if _, ok := pv.Interface().(TextUnmarshaler); ok {
+				return pv
+			}
+		}
+		return v
+	}
+	if v.IsNil() {
+		v.Set(reflect.New(v.Type().Elem()))
+	}
+	return indirect(reflect.Indirect(v))
+}
+
+func isUnifiable(rv reflect.Value) bool {
+	if rv.CanSet() {
+		return true
+	}
+	if _, ok := rv.Interface().(TextUnmarshaler); ok {
+		return true
+	}
+	return false
+}
+
+func badtype(expected string, data interface{}) error {
+	return e("cannot load TOML value of type %T into a Go %s", data, expected)
+}
diff --git a/vendor/github.com/BurntSushi/toml/decode_meta.go b/vendor/github.com/BurntSushi/toml/decode_meta.go
new file mode 100644
index 0000000000..b9914a6798
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/decode_meta.go
@@ -0,0 +1,121 @@
+package toml
+
+import "strings"
+
+// MetaData allows access to meta information about TOML data that may not
+// be inferrable via reflection. In particular, whether a key has been defined
+// and the TOML type of a key.
+type MetaData struct {
+	mapping map[string]interface{}
+	types   map[string]tomlType
+	keys    []Key
+	decoded map[string]bool
+	context Key // Used only during decoding.
+}
+
+// IsDefined returns true if the key given exists in the TOML data. The key
+// should be specified hierarchially. e.g.,
+//
+//	// access the TOML key 'a.b.c'
+//	IsDefined("a", "b", "c")
+//
+// IsDefined will return false if an empty key given. Keys are case sensitive.
+func (md *MetaData) IsDefined(key ...string) bool {
+	if len(key) == 0 {
+		return false
+	}
+
+	var hash map[string]interface{}
+	var ok bool
+	var hashOrVal interface{} = md.mapping
+	for _, k := range key {
+		if hash, ok = hashOrVal.(map[string]interface{}); !ok {
+			return false
+		}
+		if hashOrVal, ok = hash[k]; !ok {
+			return false
+		}
+	}
+	return true
+}
+
+// Type returns a string representation of the type of the key specified.
+//
+// Type will return the empty string if given an empty key or a key that
+// does not exist. Keys are case sensitive.
+func (md *MetaData) Type(key ...string) string {
+	fullkey := strings.Join(key, ".")
+	if typ, ok := md.types[fullkey]; ok {
+		return typ.typeString()
+	}
+	return ""
+}
+
+// Key is the type of any TOML key, including key groups. Use (MetaData).Keys
+// to get values of this type.
+type Key []string
+
+func (k Key) String() string {
+	return strings.Join(k, ".")
+}
+
+func (k Key) maybeQuotedAll() string {
+	var ss []string
+	for i := range k {
+		ss = append(ss, k.maybeQuoted(i))
+	}
+	return strings.Join(ss, ".")
+}
+
+func (k Key) maybeQuoted(i int) string {
+	quote := false
+	for _, c := range k[i] {
+		if !isBareKeyChar(c) {
+			quote = true
+			break
+		}
+	}
+	if quote {
+		return "\"" + strings.Replace(k[i], "\"", "\\\"", -1) + "\""
+	}
+	return k[i]
+}
+
+func (k Key) add(piece string) Key {
+	newKey := make(Key, len(k)+1)
+	copy(newKey, k)
+	newKey[len(k)] = piece
+	return newKey
+}
+
+// Keys returns a slice of every key in the TOML data, including key groups.
+// Each key is itself a slice, where the first element is the top of the
+// hierarchy and the last is the most specific.
+//
+// The list will have the same order as the keys appeared in the TOML data.
+//
+// All keys returned are non-empty.
+func (md *MetaData) Keys() []Key {
+	return md.keys
+}
+
+// Undecoded returns all keys that have not been decoded in the order in which
+// they appear in the original TOML document.
+//
+// This includes keys that haven't been decoded because of a Primitive value.
+// Once the Primitive value is decoded, the keys will be considered decoded.
+//
+// Also note that decoding into an empty interface will result in no decoding,
+// and so no keys will be considered decoded.
+//
+// In this sense, the Undecoded keys correspond to keys in the TOML document
+// that do not have a concrete type in your representation.
+func (md *MetaData) Undecoded() []Key {
+	undecoded := make([]Key, 0, len(md.keys))
+	for _, key := range md.keys {
+		if !md.decoded[key.String()] {
+			undecoded = append(undecoded, key)
+		}
+	}
+	return undecoded
+}
diff --git a/vendor/github.com/BurntSushi/toml/doc.go b/vendor/github.com/BurntSushi/toml/doc.go
new file mode 100644
index 0000000000..b371f396ed
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/doc.go
@@ -0,0 +1,27 @@
+/*
+Package toml provides facilities for decoding and encoding TOML configuration
+files via reflection. There is also support for delaying decoding with
+the Primitive type, and querying the set of keys in a TOML document with the
+MetaData type.
+
+The specification implemented: https://github.com/toml-lang/toml
+
+The sub-command github.com/BurntSushi/toml/cmd/tomlv can be used to verify
+whether a file is a valid TOML document. It can also be used to print the
+type of each key in a TOML document.
+
+Testing
+
+There are two important types of tests used for this package. The first is
+contained inside '*_test.go' files and uses the standard Go unit testing
+framework. These tests are primarily devoted to holistically testing the
+decoder and encoder.
+
+The second type of testing is used to verify the implementation's adherence
+to the TOML specification. These tests have been factored into their own
+project: https://github.com/BurntSushi/toml-test
+
+The reason the tests are in a separate project is so that they can be used by
+any implementation of TOML. Namely, it is language agnostic.
+*/
+package toml
diff --git a/vendor/github.com/BurntSushi/toml/encode.go b/vendor/github.com/BurntSushi/toml/encode.go
new file mode 100644
index 0000000000..d905c21a24
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/encode.go
@@ -0,0 +1,568 @@
+package toml
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"reflect"
+	"sort"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type tomlEncodeError struct{ error }
+
+var (
+	errArrayMixedElementTypes = errors.New(
+		"toml: cannot encode array with mixed element types")
+	errArrayNilElement = errors.New(
+		"toml: cannot encode array with nil element")
+	errNonString = errors.New(
+		"toml: cannot encode a map with non-string key type")
+	errAnonNonStruct = errors.New(
+		"toml: cannot encode an anonymous field that is not a struct")
+	errArrayNoTable = errors.New(
+		"toml: TOML array element cannot contain a table")
+	errNoKey = errors.New(
+		"toml: top-level values must be Go maps or structs")
+	errAnything = errors.New("") // used in testing
+)
+
+var quotedReplacer = strings.NewReplacer(
+	"\t", "\\t",
+	"\n", "\\n",
+	"\r", "\\r",
+	"\"", "\\\"",
+	"\\", "\\\\",
+)
+
+// Encoder controls the encoding of Go values to a TOML document to some
+// io.Writer.
+//
+// The indentation level can be controlled with the Indent field.
+type Encoder struct {
+	// A single indentation level. By default it is two spaces.
+	Indent string
+
+	// hasWritten is whether we have written any output to w yet.
+	hasWritten bool
+	w          *bufio.Writer
+}
+
+// NewEncoder returns a TOML encoder that encodes Go values to the io.Writer
+// given. By default, a single indentation level is 2 spaces.
+func NewEncoder(w io.Writer) *Encoder {
+	return &Encoder{
+		w:      bufio.NewWriter(w),
+		Indent: "  ",
+	}
+}
+
+// Encode writes a TOML representation of the Go value to the underlying
+// io.Writer. If the value given cannot be encoded to a valid TOML document,
+// then an error is returned.
+//
+// The mapping between Go values and TOML values should be precisely the same
+// as for the Decode* functions. Similarly, the TextMarshaler interface is
+// supported by encoding the resulting bytes as strings. (If you want to write
+// arbitrary binary data then you will need to use something like base64 since
+// TOML does not have any binary types.)
+//
+// When encoding TOML hashes (i.e., Go maps or structs), keys without any
+// sub-hashes are encoded first.
+//
+// If a Go map is encoded, then its keys are sorted alphabetically for
+// deterministic output. More control over this behavior may be provided if
+// there is demand for it.
+//
+// Encoding Go values without a corresponding TOML representation---like map
+// types with non-string keys---will cause an error to be returned. Similarly
+// for mixed arrays/slices, arrays/slices with nil elements, embedded
+// non-struct types and nested slices containing maps or structs.
+// (e.g., [][]map[string]string is not allowed but []map[string]string is OK
+// and so is []map[string][]string.)
+func (enc *Encoder) Encode(v interface{}) error {
+	rv := eindirect(reflect.ValueOf(v))
+	if err := enc.safeEncode(Key([]string{}), rv); err != nil {
+		return err
+	}
+	return enc.w.Flush()
+}
+
+func (enc *Encoder) safeEncode(key Key, rv reflect.Value) (err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			if terr, ok := r.(tomlEncodeError); ok {
+				err = terr.error
+				return
+			}
+			panic(r)
+		}
+	}()
+	enc.encode(key, rv)
+	return nil
+}
+
+func (enc *Encoder) encode(key Key, rv reflect.Value) {
+	// Special case. Time needs to be in ISO8601 format.
+	// Special case. If we can marshal the type to text, then we used that.
+	// Basically, this prevents the encoder for handling these types as
+	// generic structs (or whatever the underlying type of a TextMarshaler is).
+	switch rv.Interface().(type) {
+	case time.Time, TextMarshaler:
+		enc.keyEqElement(key, rv)
+		return
+	}
+
+	k := rv.Kind()
+	switch k {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
+		reflect.Int64,
+		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
+		reflect.Uint64,
+		reflect.Float32, reflect.Float64, reflect.String, reflect.Bool:
+		enc.keyEqElement(key, rv)
+	case reflect.Array, reflect.Slice:
+		if typeEqual(tomlArrayHash, tomlTypeOfGo(rv)) {
+			enc.eArrayOfTables(key, rv)
+		} else {
+			enc.keyEqElement(key, rv)
+		}
+	case reflect.Interface:
+		if rv.IsNil() {
+			return
+		}
+		enc.encode(key, rv.Elem())
+	case reflect.Map:
+		if rv.IsNil() {
+			return
+		}
+		enc.eTable(key, rv)
+	case reflect.Ptr:
+		if rv.IsNil() {
+			return
+		}
+		enc.encode(key, rv.Elem())
+	case reflect.Struct:
+		enc.eTable(key, rv)
+	default:
+		panic(e("unsupported type for key '%s': %s", key, k))
+	}
+}
+
+// eElement encodes any value that can be an array element (primitives and
+// arrays).
+func (enc *Encoder) eElement(rv reflect.Value) {
+	switch v := rv.Interface().(type) {
+	case time.Time:
+		// Special case time.Time as a primitive. Has to come before
+		// TextMarshaler below because time.Time implements
+		// encoding.TextMarshaler, but we need to always use UTC.
+		enc.wf(v.UTC().Format("2006-01-02T15:04:05Z"))
+		return
+	case TextMarshaler:
+		// Special case. Use text marshaler if it's available for this value.
+		if s, err := v.MarshalText(); err != nil {
+			encPanic(err)
+		} else {
+			enc.writeQuoted(string(s))
+		}
+		return
+	}
+	switch rv.Kind() {
+	case reflect.Bool:
+		enc.wf(strconv.FormatBool(rv.Bool()))
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
+		reflect.Int64:
+		enc.wf(strconv.FormatInt(rv.Int(), 10))
+	case reflect.Uint, reflect.Uint8, reflect.Uint16,
+		reflect.Uint32, reflect.Uint64:
+		enc.wf(strconv.FormatUint(rv.Uint(), 10))
+	case reflect.Float32:
+		enc.wf(floatAddDecimal(strconv.FormatFloat(rv.Float(), 'f', -1, 32)))
+	case reflect.Float64:
+		enc.wf(floatAddDecimal(strconv.FormatFloat(rv.Float(), 'f', -1, 64)))
+	case reflect.Array, reflect.Slice:
+		enc.eArrayOrSliceElement(rv)
+	case reflect.Interface:
+		enc.eElement(rv.Elem())
+	case reflect.String:
+		enc.writeQuoted(rv.String())
+	default:
+		panic(e("unexpected primitive type: %s", rv.Kind()))
+	}
+}
+
+// By the TOML spec, all floats must have a decimal with at least one
+// number on either side.
+func floatAddDecimal(fstr string) string {
+	if !strings.Contains(fstr, ".") {
+		return fstr + ".0"
+	}
+	return fstr
+}
+
+func (enc *Encoder) writeQuoted(s string) {
+	enc.wf("\"%s\"", quotedReplacer.Replace(s))
+}
+
+func (enc *Encoder) eArrayOrSliceElement(rv reflect.Value) {
+	length := rv.Len()
+	enc.wf("[")
+	for i := 0; i < length; i++ {
+		elem := rv.Index(i)
+		enc.eElement(elem)
+		if i != length-1 {
+			enc.wf(", ")
+		}
+	}
+	enc.wf("]")
+}
+
+func (enc *Encoder) eArrayOfTables(key Key, rv reflect.Value) {
+	if len(key) == 0 {
+		encPanic(errNoKey)
+	}
+	for i := 0; i < rv.Len(); i++ {
+		trv := rv.Index(i)
+		if isNil(trv) {
+			continue
+		}
+		panicIfInvalidKey(key)
+		enc.newline()
+		enc.wf("%s[[%s]]", enc.indentStr(key), key.maybeQuotedAll())
+		enc.newline()
+		enc.eMapOrStruct(key, trv)
+	}
+}
+
+func (enc *Encoder) eTable(key Key, rv reflect.Value) {
+	panicIfInvalidKey(key)
+	if len(key) == 1 {
+		// Output an extra newline between top-level tables.
+		// (The newline isn't written if nothing else has been written though.)
+		enc.newline()
+	}
+	if len(key) > 0 {
+		enc.wf("%s[%s]", enc.indentStr(key), key.maybeQuotedAll())
+		enc.newline()
+	}
+	enc.eMapOrStruct(key, rv)
+}
+
+func (enc *Encoder) eMapOrStruct(key Key, rv reflect.Value) {
+	switch rv := eindirect(rv); rv.Kind() {
+	case reflect.Map:
+		enc.eMap(key, rv)
+	case reflect.Struct:
+		enc.eStruct(key, rv)
+	default:
+		panic("eTable: unhandled reflect.Value Kind: " + rv.Kind().String())
+	}
+}
+
+func (enc *Encoder) eMap(key Key, rv reflect.Value) {
+	rt := rv.Type()
+	if rt.Key().Kind() != reflect.String {
+		encPanic(errNonString)
+	}
+
+	// Sort keys so that we have deterministic output. And write keys directly
+	// underneath this key first, before writing sub-structs or sub-maps.
+	var mapKeysDirect, mapKeysSub []string
+	for _, mapKey := range rv.MapKeys() {
+		k := mapKey.String()
+		if typeIsHash(tomlTypeOfGo(rv.MapIndex(mapKey))) {
+			mapKeysSub = append(mapKeysSub, k)
+		} else {
+			mapKeysDirect = append(mapKeysDirect, k)
+		}
+	}
+
+	var writeMapKeys = func(mapKeys []string) {
+		sort.Strings(mapKeys)
+		for _, mapKey := range mapKeys {
+			mrv := rv.MapIndex(reflect.ValueOf(mapKey))
+			if isNil(mrv) {
+				// Don't write anything for nil fields.
+				continue
+			}
+			enc.encode(key.add(mapKey), mrv)
+		}
+	}
+	writeMapKeys(mapKeysDirect)
+	writeMapKeys(mapKeysSub)
+}
+
+func (enc *Encoder) eStruct(key Key, rv reflect.Value) {
+	// Write keys for fields directly under this key first, because if we write
+	// a field that creates a new table, then all keys under it will be in that
+	// table (not the one we're writing here).
+	rt := rv.Type()
+	var fieldsDirect, fieldsSub [][]int
+	var addFields func(rt reflect.Type, rv reflect.Value, start []int)
+	addFields = func(rt reflect.Type, rv reflect.Value, start []int) {
+		for i := 0; i < rt.NumField(); i++ {
+			f := rt.Field(i)
+			// skip unexported fields
+			if f.PkgPath != "" && !f.Anonymous {
+				continue
+			}
+			frv := rv.Field(i)
+			if f.Anonymous {
+				t := f.Type
+				switch t.Kind() {
+				case reflect.Struct:
+					// Treat anonymous struct fields with
+					// tag names as though they are not
+					// anonymous, like encoding/json does.
+					if getOptions(f.Tag).name == "" {
+						addFields(t, frv, f.Index)
+						continue
+					}
+				case reflect.Ptr:
+					if t.Elem().Kind() == reflect.Struct &&
+						getOptions(f.Tag).name == "" {
+						if !frv.IsNil() {
+							addFields(t.Elem(), frv.Elem(), f.Index)
+						}
+						continue
+					}
+					// Fall through to the normal field encoding logic below
+					// for non-struct anonymous fields.
+				}
+			}
+
+			if typeIsHash(tomlTypeOfGo(frv)) {
+				fieldsSub = append(fieldsSub, append(start, f.Index...))
+			} else {
+				fieldsDirect = append(fieldsDirect, append(start, f.Index...))
+			}
+		}
+	}
+	addFields(rt, rv, nil)
+
+	var writeFields = func(fields [][]int) {
+		for _, fieldIndex := range fields {
+			sft := rt.FieldByIndex(fieldIndex)
+			sf := rv.FieldByIndex(fieldIndex)
+			if isNil(sf) {
+				// Don't write anything for nil fields.
+				continue
+			}
+
+			opts := getOptions(sft.Tag)
+			if opts.skip {
+				continue
+			}
+			keyName := sft.Name
+			if opts.name != "" {
+				keyName = opts.name
+			}
+			if opts.omitempty && isEmpty(sf) {
+				continue
+			}
+			if opts.omitzero && isZero(sf) {
+				continue
+			}
+
+			enc.encode(key.add(keyName), sf)
+		}
+	}
+	writeFields(fieldsDirect)
+	writeFields(fieldsSub)
+}
+
+// tomlTypeName returns the TOML type name of the Go value's type. It is
+// used to determine whether the types of array elements are mixed (which is
+// forbidden). If the Go value is nil, then it is illegal for it to be an array
+// element, and valueIsNil is returned as true.
+
+// Returns the TOML type of a Go value. The type may be `nil`, which means
+// no concrete TOML type could be found.
+func tomlTypeOfGo(rv reflect.Value) tomlType {
+	if isNil(rv) || !rv.IsValid() {
+		return nil
+	}
+	switch rv.Kind() {
+	case reflect.Bool:
+		return tomlBool
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32,
+		reflect.Int64,
+		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32,
+		reflect.Uint64:
+		return tomlInteger
+	case reflect.Float32, reflect.Float64:
+		return tomlFloat
+	case reflect.Array, reflect.Slice:
+		if typeEqual(tomlHash, tomlArrayType(rv)) {
+			return tomlArrayHash
+		}
+		return tomlArray
+	case reflect.Ptr, reflect.Interface:
+		return tomlTypeOfGo(rv.Elem())
+	case reflect.String:
+		return tomlString
+	case reflect.Map:
+		return tomlHash
+	case reflect.Struct:
+		switch rv.Interface().(type) {
+		case time.Time:
+			return tomlDatetime
+		case TextMarshaler:
+			return tomlString
+		default:
+			return tomlHash
+		}
+	default:
+		panic("unexpected reflect.Kind: " + rv.Kind().String())
+	}
+}
+
+// tomlArrayType returns the element type of a TOML array. The type returned
+// may be nil if it cannot be determined (e.g., a nil slice or a zero length
+// slize). This function may also panic if it finds a type that cannot be
+// expressed in TOML (such as nil elements, heterogeneous arrays or directly
+// nested arrays of tables).
+func tomlArrayType(rv reflect.Value) tomlType {
+	if isNil(rv) || !rv.IsValid() || rv.Len() == 0 {
+		return nil
+	}
+	firstType := tomlTypeOfGo(rv.Index(0))
+	if firstType == nil {
+		encPanic(errArrayNilElement)
+	}
+
+	rvlen := rv.Len()
+	for i := 1; i < rvlen; i++ {
+		elem := rv.Index(i)
+		switch elemType := tomlTypeOfGo(elem); {
+		case elemType == nil:
+			encPanic(errArrayNilElement)
+		case !typeEqual(firstType, elemType):
+			encPanic(errArrayMixedElementTypes)
+		}
+	}
+	// If we have a nested array, then we must make sure that the nested
+	// array contains ONLY primitives.
+	// This checks arbitrarily nested arrays.
+	if typeEqual(firstType, tomlArray) || typeEqual(firstType, tomlArrayHash) {
+		nest := tomlArrayType(eindirect(rv.Index(0)))
+		if typeEqual(nest, tomlHash) || typeEqual(nest, tomlArrayHash) {
+			encPanic(errArrayNoTable)
+		}
+	}
+	return firstType
+}
+
+type tagOptions struct {
+	skip      bool // "-"
+	name      string
+	omitempty bool
+	omitzero  bool
+}
+
+func getOptions(tag reflect.StructTag) tagOptions {
+	t := tag.Get("toml")
+	if t == "-" {
+		return tagOptions{skip: true}
+	}
+	var opts tagOptions
+	parts := strings.Split(t, ",")
+	opts.name = parts[0]
+	for _, s := range parts[1:] {
+		switch s {
+		case "omitempty":
+			opts.omitempty = true
+		case "omitzero":
+			opts.omitzero = true
+		}
+	}
+	return opts
+}
+
+func isZero(rv reflect.Value) bool {
+	switch rv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int() == 0
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return rv.Uint() == 0
+	case reflect.Float32, reflect.Float64:
+		return rv.Float() == 0.0
+	}
+	return false
+}
+
+func isEmpty(rv reflect.Value) bool {
+	switch rv.Kind() {
+	case reflect.Array, reflect.Slice, reflect.Map, reflect.String:
+		return rv.Len() == 0
+	case reflect.Bool:
+		return !rv.Bool()
+	}
+	return false
+}
+
+func (enc *Encoder) newline() {
+	if enc.hasWritten {
+		enc.wf("\n")
+	}
+}
+
+func (enc *Encoder) keyEqElement(key Key, val reflect.Value) {
+	if len(key) == 0 {
+		encPanic(errNoKey)
+	}
+	panicIfInvalidKey(key)
+	enc.wf("%s%s = ", enc.indentStr(key), key.maybeQuoted(len(key)-1))
+	enc.eElement(val)
+	enc.newline()
+}
+
+func (enc *Encoder) wf(format string, v ...interface{}) {
+	if _, err := fmt.Fprintf(enc.w, format, v...); err != nil {
+		encPanic(err)
+	}
+	enc.hasWritten = true
+}
+
+func (enc *Encoder) indentStr(key Key) string {
+	return strings.Repeat(enc.Indent, len(key)-1)
+}
+
+func encPanic(err error) {
+	panic(tomlEncodeError{err})
+}
+
+func eindirect(v reflect.Value) reflect.Value {
+	switch v.Kind() {
+	case reflect.Ptr, reflect.Interface:
+		return eindirect(v.Elem())
+	default:
+		return v
+	}
+}
+
+func isNil(rv reflect.Value) bool {
+	switch rv.Kind() {
+	case reflect.Interface, reflect.Map, reflect.Ptr, reflect.Slice:
+		return rv.IsNil()
+	default:
+		return false
+	}
+}
+
+func panicIfInvalidKey(key Key) {
+	for _, k := range key {
+		if len(k) == 0 {
+			encPanic(e("Key '%s' is not a valid table name. Key names "+
+				"cannot be empty.", key.maybeQuotedAll()))
+		}
+	}
+}
+
+func isValidKeyName(s string) bool {
+	return len(s) != 0
+}
diff --git a/vendor/github.com/BurntSushi/toml/encoding_types.go b/vendor/github.com/BurntSushi/toml/encoding_types.go
new file mode 100644
index 0000000000..d36e1dd600
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/encoding_types.go
@@ -0,0 +1,19 @@
+// +build go1.2
+
+package toml
+
+// In order to support Go 1.1, we define our own TextMarshaler and
+// TextUnmarshaler types. For Go 1.2+, we just alias them with the
+// standard library interfaces.
+
+import (
+	"encoding"
+)
+
+// TextMarshaler is a synonym for encoding.TextMarshaler. It is defined here
+// so that Go 1.1 can be supported.
+type TextMarshaler encoding.TextMarshaler
+
+// TextUnmarshaler is a synonym for encoding.TextUnmarshaler. It is defined
+// here so that Go 1.1 can be supported.
+type TextUnmarshaler encoding.TextUnmarshaler
diff --git a/vendor/github.com/BurntSushi/toml/encoding_types_1.1.go b/vendor/github.com/BurntSushi/toml/encoding_types_1.1.go
new file mode 100644
index 0000000000..e8d503d046
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/encoding_types_1.1.go
@@ -0,0 +1,18 @@
+// +build !go1.2
+
+package toml
+
+// These interfaces were introduced in Go 1.2, so we add them manually when
+// compiling for Go 1.1.
+
+// TextMarshaler is a synonym for encoding.TextMarshaler. It is defined here
+// so that Go 1.1 can be supported.
+type TextMarshaler interface {
+	MarshalText() (text []byte, err error)
+}
+
+// TextUnmarshaler is a synonym for encoding.TextUnmarshaler. It is defined
+// here so that Go 1.1 can be supported.
+type TextUnmarshaler interface {
+	UnmarshalText(text []byte) error
+}
diff --git a/vendor/github.com/BurntSushi/toml/lex.go b/vendor/github.com/BurntSushi/toml/lex.go
new file mode 100644
index 0000000000..e0a742a887
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/lex.go
@@ -0,0 +1,953 @@
+package toml
+
+import (
+	"fmt"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+type itemType int
+
+const (
+	itemError itemType = iota
+	itemNIL            // used in the parser to indicate no type
+	itemEOF
+	itemText
+	itemString
+	itemRawString
+	itemMultilineString
+	itemRawMultilineString
+	itemBool
+	itemInteger
+	itemFloat
+	itemDatetime
+	itemArray // the start of an array
+	itemArrayEnd
+	itemTableStart
+	itemTableEnd
+	itemArrayTableStart
+	itemArrayTableEnd
+	itemKeyStart
+	itemCommentStart
+	itemInlineTableStart
+	itemInlineTableEnd
+)
+
+const (
+	eof              = 0
+	comma            = ','
+	tableStart       = '['
+	tableEnd         = ']'
+	arrayTableStart  = '['
+	arrayTableEnd    = ']'
+	tableSep         = '.'
+	keySep           = '='
+	arrayStart       = '['
+	arrayEnd         = ']'
+	commentStart     = '#'
+	stringStart      = '"'
+	stringEnd        = '"'
+	rawStringStart   = '\''
+	rawStringEnd     = '\''
+	inlineTableStart = '{'
+	inlineTableEnd   = '}'
+)
+
+type stateFn func(lx *lexer) stateFn
+
+type lexer struct {
+	input string
+	start int
+	pos   int
+	line  int
+	state stateFn
+	items chan item
+
+	// Allow for backing up up to three runes.
+	// This is necessary because TOML contains 3-rune tokens (""" and ''').
+	prevWidths [3]int
+	nprev      int // how many of prevWidths are in use
+	// If we emit an eof, we can still back up, but it is not OK to call
+	// next again.
+	atEOF bool
+
+	// A stack of state functions used to maintain context.
+	// The idea is to reuse parts of the state machine in various places.
+	// For example, values can appear at the top level or within arbitrarily
+	// nested arrays. The last state on the stack is used after a value has
+	// been lexed. Similarly for comments.
+	stack []stateFn
+}
+
+type item struct {
+	typ  itemType
+	val  string
+	line int
+}
+
+func (lx *lexer) nextItem() item {
+	for {
+		select {
+		case item := <-lx.items:
+			return item
+		default:
+			lx.state = lx.state(lx)
+		}
+	}
+}
+
+func lex(input string) *lexer {
+	lx := &lexer{
+		input: input,
+		state: lexTop,
+		line:  1,
+		items: make(chan item, 10),
+		stack: make([]stateFn, 0, 10),
+	}
+	return lx
+}
+
+func (lx *lexer) push(state stateFn) {
+	lx.stack = append(lx.stack, state)
+}
+
+func (lx *lexer) pop() stateFn {
+	if len(lx.stack) == 0 {
+		return lx.errorf("BUG in lexer: no states to pop")
+	}
+	last := lx.stack[len(lx.stack)-1]
+	lx.stack = lx.stack[0 : len(lx.stack)-1]
+	return last
+}
+
+func (lx *lexer) current() string {
+	return lx.input[lx.start:lx.pos]
+}
+
+func (lx *lexer) emit(typ itemType) {
+	lx.items <- item{typ, lx.current(), lx.line}
+	lx.start = lx.pos
+}
+
+func (lx *lexer) emitTrim(typ itemType) {
+	lx.items <- item{typ, strings.TrimSpace(lx.current()), lx.line}
+	lx.start = lx.pos
+}
+
+func (lx *lexer) next() (r rune) {
+	if lx.atEOF {
+		panic("next called after EOF")
+	}
+	if lx.pos >= len(lx.input) {
+		lx.atEOF = true
+		return eof
+	}
+
+	if lx.input[lx.pos] == '\n' {
+		lx.line++
+	}
+	lx.prevWidths[2] = lx.prevWidths[1]
+	lx.prevWidths[1] = lx.prevWidths[0]
+	if lx.nprev < 3 {
+		lx.nprev++
+	}
+	r, w := utf8.DecodeRuneInString(lx.input[lx.pos:])
+	lx.prevWidths[0] = w
+	lx.pos += w
+	return r
+}
+
+// ignore skips over the pending input before this point.
+func (lx *lexer) ignore() {
+	lx.start = lx.pos
+}
+
+// backup steps back one rune. Can be called only twice between calls to next.
+func (lx *lexer) backup() {
+	if lx.atEOF {
+		lx.atEOF = false
+		return
+	}
+	if lx.nprev < 1 {
+		panic("backed up too far")
+	}
+	w := lx.prevWidths[0]
+	lx.prevWidths[0] = lx.prevWidths[1]
+	lx.prevWidths[1] = lx.prevWidths[2]
+	lx.nprev--
+	lx.pos -= w
+	if lx.pos < len(lx.input) && lx.input[lx.pos] == '\n' {
+		lx.line--
+	}
+}
+
+// accept consumes the next rune if it's equal to `valid`.
+func (lx *lexer) accept(valid rune) bool {
+	if lx.next() == valid {
+		return true
+	}
+	lx.backup()
+	return false
+}
+
+// peek returns but does not consume the next rune in the input.
+func (lx *lexer) peek() rune {
+	r := lx.next()
+	lx.backup()
+	return r
+}
+
+// skip ignores all input that matches the given predicate.
+func (lx *lexer) skip(pred func(rune) bool) {
+	for {
+		r := lx.next()
+		if pred(r) {
+			continue
+		}
+		lx.backup()
+		lx.ignore()
+		return
+	}
+}
+
+// errorf stops all lexing by emitting an error and returning `nil`.
+// Note that any value that is a character is escaped if it's a special
+// character (newlines, tabs, etc.).
+func (lx *lexer) errorf(format string, values ...interface{}) stateFn {
+	lx.items <- item{
+		itemError,
+		fmt.Sprintf(format, values...),
+		lx.line,
+	}
+	return nil
+}
+
+// lexTop consumes elements at the top level of TOML data.
+func lexTop(lx *lexer) stateFn {
+	r := lx.next()
+	if isWhitespace(r) || isNL(r) {
+		return lexSkip(lx, lexTop)
+	}
+	switch r {
+	case commentStart:
+		lx.push(lexTop)
+		return lexCommentStart
+	case tableStart:
+		return lexTableStart
+	case eof:
+		if lx.pos > lx.start {
+			return lx.errorf("unexpected EOF")
+		}
+		lx.emit(itemEOF)
+		return nil
+	}
+
+	// At this point, the only valid item can be a key, so we back up
+	// and let the key lexer do the rest.
+	lx.backup()
+	lx.push(lexTopEnd)
+	return lexKeyStart
+}
+
+// lexTopEnd is entered whenever a top-level item has been consumed. (A value
+// or a table.) It must see only whitespace, and will turn back to lexTop
+// upon a newline. If it sees EOF, it will quit the lexer successfully.
+func lexTopEnd(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case r == commentStart:
+		// a comment will read to a newline for us.
+		lx.push(lexTop)
+		return lexCommentStart
+	case isWhitespace(r):
+		return lexTopEnd
+	case isNL(r):
+		lx.ignore()
+		return lexTop
+	case r == eof:
+		lx.emit(itemEOF)
+		return nil
+	}
+	return lx.errorf("expected a top-level item to end with a newline, "+
+		"comment, or EOF, but got %q instead", r)
+}
+
+// lexTable lexes the beginning of a table. Namely, it makes sure that
+// it starts with a character other than '.' and ']'.
+// It assumes that '[' has already been consumed.
+// It also handles the case that this is an item in an array of tables.
+// e.g., '[[name]]'.
+func lexTableStart(lx *lexer) stateFn {
+	if lx.peek() == arrayTableStart {
+		lx.next()
+		lx.emit(itemArrayTableStart)
+		lx.push(lexArrayTableEnd)
+	} else {
+		lx.emit(itemTableStart)
+		lx.push(lexTableEnd)
+	}
+	return lexTableNameStart
+}
+
+func lexTableEnd(lx *lexer) stateFn {
+	lx.emit(itemTableEnd)
+	return lexTopEnd
+}
+
+func lexArrayTableEnd(lx *lexer) stateFn {
+	if r := lx.next(); r != arrayTableEnd {
+		return lx.errorf("expected end of table array name delimiter %q, "+
+			"but got %q instead", arrayTableEnd, r)
+	}
+	lx.emit(itemArrayTableEnd)
+	return lexTopEnd
+}
+
+func lexTableNameStart(lx *lexer) stateFn {
+	lx.skip(isWhitespace)
+	switch r := lx.peek(); {
+	case r == tableEnd || r == eof:
+		return lx.errorf("unexpected end of table name " +
+			"(table names cannot be empty)")
+	case r == tableSep:
+		return lx.errorf("unexpected table separator " +
+			"(table names cannot be empty)")
+	case r == stringStart || r == rawStringStart:
+		lx.ignore()
+		lx.push(lexTableNameEnd)
+		return lexValue // reuse string lexing
+	default:
+		return lexBareTableName
+	}
+}
+
+// lexBareTableName lexes the name of a table. It assumes that at least one
+// valid character for the table has already been read.
+func lexBareTableName(lx *lexer) stateFn {
+	r := lx.next()
+	if isBareKeyChar(r) {
+		return lexBareTableName
+	}
+	lx.backup()
+	lx.emit(itemText)
+	return lexTableNameEnd
+}
+
+// lexTableNameEnd reads the end of a piece of a table name, optionally
+// consuming whitespace.
+func lexTableNameEnd(lx *lexer) stateFn {
+	lx.skip(isWhitespace)
+	switch r := lx.next(); {
+	case isWhitespace(r):
+		return lexTableNameEnd
+	case r == tableSep:
+		lx.ignore()
+		return lexTableNameStart
+	case r == tableEnd:
+		return lx.pop()
+	default:
+		return lx.errorf("expected '.' or ']' to end table name, "+
+			"but got %q instead", r)
+	}
+}
+
+// lexKeyStart consumes a key name up until the first non-whitespace character.
+// lexKeyStart will ignore whitespace.
+func lexKeyStart(lx *lexer) stateFn {
+	r := lx.peek()
+	switch {
+	case r == keySep:
+		return lx.errorf("unexpected key separator %q", keySep)
+	case isWhitespace(r) || isNL(r):
+		lx.next()
+		return lexSkip(lx, lexKeyStart)
+	case r == stringStart || r == rawStringStart:
+		lx.ignore()
+		lx.emit(itemKeyStart)
+		lx.push(lexKeyEnd)
+		return lexValue // reuse string lexing
+	default:
+		lx.ignore()
+		lx.emit(itemKeyStart)
+		return lexBareKey
+	}
+}
+
+// lexBareKey consumes the text of a bare key. Assumes that the first character
+// (which is not whitespace) has not yet been consumed.
+func lexBareKey(lx *lexer) stateFn {
+	switch r := lx.next(); {
+	case isBareKeyChar(r):
+		return lexBareKey
+	case isWhitespace(r):
+		lx.backup()
+		lx.emit(itemText)
+		return lexKeyEnd
+	case r == keySep:
+		lx.backup()
+		lx.emit(itemText)
+		return lexKeyEnd
+	default:
+		return lx.errorf("bare keys cannot contain %q", r)
+	}
+}
+
+// lexKeyEnd consumes the end of a key and trims whitespace (up to the key
+// separator).
+func lexKeyEnd(lx *lexer) stateFn {
+	switch r := lx.next(); {
+	case r == keySep:
+		return lexSkip(lx, lexValue)
+	case isWhitespace(r):
+		return lexSkip(lx, lexKeyEnd)
+	default:
+		return lx.errorf("expected key separator %q, but got %q instead",
+			keySep, r)
+	}
+}
+
+// lexValue starts the consumption of a value anywhere a value is expected.
+// lexValue will ignore whitespace.
+// After a value is lexed, the last state on the next is popped and returned.
+func lexValue(lx *lexer) stateFn {
+	// We allow whitespace to precede a value, but NOT newlines.
+	// In array syntax, the array states are responsible for ignoring newlines.
+	r := lx.next()
+	switch {
+	case isWhitespace(r):
+		return lexSkip(lx, lexValue)
+	case isDigit(r):
+		lx.backup() // avoid an extra state and use the same as above
+		return lexNumberOrDateStart
+	}
+	switch r {
+	case arrayStart:
+		lx.ignore()
+		lx.emit(itemArray)
+		return lexArrayValue
+	case inlineTableStart:
+		lx.ignore()
+		lx.emit(itemInlineTableStart)
+		return lexInlineTableValue
+	case stringStart:
+		if lx.accept(stringStart) {
+			if lx.accept(stringStart) {
+				lx.ignore() // Ignore """
+				return lexMultilineString
+			}
+			lx.backup()
+		}
+		lx.ignore() // ignore the '"'
+		return lexString
+	case rawStringStart:
+		if lx.accept(rawStringStart) {
+			if lx.accept(rawStringStart) {
+				lx.ignore() // Ignore """
+				return lexMultilineRawString
+			}
+			lx.backup()
+		}
+		lx.ignore() // ignore the "'"
+		return lexRawString
+	case '+', '-':
+		return lexNumberStart
+	case '.': // special error case, be kind to users
+		return lx.errorf("floats must start with a digit, not '.'")
+	}
+	if unicode.IsLetter(r) {
+		// Be permissive here; lexBool will give a nice error if the
+		// user wrote something like
+		//   x = foo
+		// (i.e. not 'true' or 'false' but is something else word-like.)
+		lx.backup()
+		return lexBool
+	}
+	return lx.errorf("expected value but found %q instead", r)
+}
+
+// lexArrayValue consumes one value in an array. It assumes that '[' or ','
+// have already been consumed. All whitespace and newlines are ignored.
+func lexArrayValue(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case isWhitespace(r) || isNL(r):
+		return lexSkip(lx, lexArrayValue)
+	case r == commentStart:
+		lx.push(lexArrayValue)
+		return lexCommentStart
+	case r == comma:
+		return lx.errorf("unexpected comma")
+	case r == arrayEnd:
+		// NOTE(caleb): The spec isn't clear about whether you can have
+		// a trailing comma or not, so we'll allow it.
+		return lexArrayEnd
+	}
+
+	lx.backup()
+	lx.push(lexArrayValueEnd)
+	return lexValue
+}
+
+// lexArrayValueEnd consumes everything between the end of an array value and
+// the next value (or the end of the array): it ignores whitespace and newlines
+// and expects either a ',' or a ']'.
+func lexArrayValueEnd(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case isWhitespace(r) || isNL(r):
+		return lexSkip(lx, lexArrayValueEnd)
+	case r == commentStart:
+		lx.push(lexArrayValueEnd)
+		return lexCommentStart
+	case r == comma:
+		lx.ignore()
+		return lexArrayValue // move on to the next value
+	case r == arrayEnd:
+		return lexArrayEnd
+	}
+	return lx.errorf(
+		"expected a comma or array terminator %q, but got %q instead",
+		arrayEnd, r,
+	)
+}
+
+// lexArrayEnd finishes the lexing of an array.
+// It assumes that a ']' has just been consumed.
+func lexArrayEnd(lx *lexer) stateFn {
+	lx.ignore()
+	lx.emit(itemArrayEnd)
+	return lx.pop()
+}
+
+// lexInlineTableValue consumes one key/value pair in an inline table.
+// It assumes that '{' or ',' have already been consumed. Whitespace is ignored.
+func lexInlineTableValue(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case isWhitespace(r):
+		return lexSkip(lx, lexInlineTableValue)
+	case isNL(r):
+		return lx.errorf("newlines not allowed within inline tables")
+	case r == commentStart:
+		lx.push(lexInlineTableValue)
+		return lexCommentStart
+	case r == comma:
+		return lx.errorf("unexpected comma")
+	case r == inlineTableEnd:
+		return lexInlineTableEnd
+	}
+	lx.backup()
+	lx.push(lexInlineTableValueEnd)
+	return lexKeyStart
+}
+
+// lexInlineTableValueEnd consumes everything between the end of an inline table
+// key/value pair and the next pair (or the end of the table):
+// it ignores whitespace and expects either a ',' or a '}'.
+func lexInlineTableValueEnd(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case isWhitespace(r):
+		return lexSkip(lx, lexInlineTableValueEnd)
+	case isNL(r):
+		return lx.errorf("newlines not allowed within inline tables")
+	case r == commentStart:
+		lx.push(lexInlineTableValueEnd)
+		return lexCommentStart
+	case r == comma:
+		lx.ignore()
+		return lexInlineTableValue
+	case r == inlineTableEnd:
+		return lexInlineTableEnd
+	}
+	return lx.errorf("expected a comma or an inline table terminator %q, "+
+		"but got %q instead", inlineTableEnd, r)
+}
+
+// lexInlineTableEnd finishes the lexing of an inline table.
+// It assumes that a '}' has just been consumed.
+func lexInlineTableEnd(lx *lexer) stateFn {
+	lx.ignore()
+	lx.emit(itemInlineTableEnd)
+	return lx.pop()
+}
+
+// lexString consumes the inner contents of a string. It assumes that the
+// beginning '"' has already been consumed and ignored.
+func lexString(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case r == eof:
+		return lx.errorf("unexpected EOF")
+	case isNL(r):
+		return lx.errorf("strings cannot contain newlines")
+	case r == '\\':
+		lx.push(lexString)
+		return lexStringEscape
+	case r == stringEnd:
+		lx.backup()
+		lx.emit(itemString)
+		lx.next()
+		lx.ignore()
+		return lx.pop()
+	}
+	return lexString
+}
+
+// lexMultilineString consumes the inner contents of a string. It assumes that
+// the beginning '"""' has already been consumed and ignored.
+func lexMultilineString(lx *lexer) stateFn {
+	switch lx.next() {
+	case eof:
+		return lx.errorf("unexpected EOF")
+	case '\\':
+		return lexMultilineStringEscape
+	case stringEnd:
+		if lx.accept(stringEnd) {
+			if lx.accept(stringEnd) {
+				lx.backup()
+				lx.backup()
+				lx.backup()
+				lx.emit(itemMultilineString)
+				lx.next()
+				lx.next()
+				lx.next()
+				lx.ignore()
+				return lx.pop()
+			}
+			lx.backup()
+		}
+	}
+	return lexMultilineString
+}
+
+// lexRawString consumes a raw string. Nothing can be escaped in such a string.
+// It assumes that the beginning "'" has already been consumed and ignored.
+func lexRawString(lx *lexer) stateFn {
+	r := lx.next()
+	switch {
+	case r == eof:
+		return lx.errorf("unexpected EOF")
+	case isNL(r):
+		return lx.errorf("strings cannot contain newlines")
+	case r == rawStringEnd:
+		lx.backup()
+		lx.emit(itemRawString)
+		lx.next()
+		lx.ignore()
+		return lx.pop()
+	}
+	return lexRawString
+}
+
+// lexMultilineRawString consumes a raw string. Nothing can be escaped in such
+// a string. It assumes that the beginning "'''" has already been consumed and
+// ignored.
+func lexMultilineRawString(lx *lexer) stateFn {
+	switch lx.next() {
+	case eof:
+		return lx.errorf("unexpected EOF")
+	case rawStringEnd:
+		if lx.accept(rawStringEnd) {
+			if lx.accept(rawStringEnd) {
+				lx.backup()
+				lx.backup()
+				lx.backup()
+				lx.emit(itemRawMultilineString)
+				lx.next()
+				lx.next()
+				lx.next()
+				lx.ignore()
+				return lx.pop()
+			}
+			lx.backup()
+		}
+	}
+	return lexMultilineRawString
+}
+
+// lexMultilineStringEscape consumes an escaped character. It assumes that the
+// preceding '\\' has already been consumed.
+func lexMultilineStringEscape(lx *lexer) stateFn {
+	// Handle the special case first:
+	if isNL(lx.next()) {
+		return lexMultilineString
+	}
+	lx.backup()
+	lx.push(lexMultilineString)
+	return lexStringEscape(lx)
+}
+
+func lexStringEscape(lx *lexer) stateFn {
+	r := lx.next()
+	switch r {
+	case 'b':
+		fallthrough
+	case 't':
+		fallthrough
+	case 'n':
+		fallthrough
+	case 'f':
+		fallthrough
+	case 'r':
+		fallthrough
+	case '"':
+		fallthrough
+	case '\\':
+		return lx.pop()
+	case 'u':
+		return lexShortUnicodeEscape
+	case 'U':
+		return lexLongUnicodeEscape
+	}
+	return lx.errorf("invalid escape character %q; only the following "+
+		"escape characters are allowed: "+
+		`\b, \t, \n, \f, \r, \", \\, \uXXXX, and \UXXXXXXXX`, r)
+}
+
+func lexShortUnicodeEscape(lx *lexer) stateFn {
+	var r rune
+	for i := 0; i < 4; i++ {
+		r = lx.next()
+		if !isHexadecimal(r) {
+			return lx.errorf(`expected four hexadecimal digits after '\u', `+
+				"but got %q instead", lx.current())
+		}
+	}
+	return lx.pop()
+}
+
+func lexLongUnicodeEscape(lx *lexer) stateFn {
+	var r rune
+	for i := 0; i < 8; i++ {
+		r = lx.next()
+		if !isHexadecimal(r) {
+			return lx.errorf(`expected eight hexadecimal digits after '\U', `+
+				"but got %q instead", lx.current())
+		}
+	}
+	return lx.pop()
+}
+
+// lexNumberOrDateStart consumes either an integer, a float, or datetime.
+func lexNumberOrDateStart(lx *lexer) stateFn {
+	r := lx.next()
+	if isDigit(r) {
+		return lexNumberOrDate
+	}
+	switch r {
+	case '_':
+		return lexNumber
+	case 'e', 'E':
+		return lexFloat
+	case '.':
+		return lx.errorf("floats must start with a digit, not '.'")
+	}
+	return lx.errorf("expected a digit but got %q", r)
+}
+
+// lexNumberOrDate consumes either an integer, float or datetime.
+func lexNumberOrDate(lx *lexer) stateFn {
+	r := lx.next()
+	if isDigit(r) {
+		return lexNumberOrDate
+	}
+	switch r {
+	case '-':
+		return lexDatetime
+	case '_':
+		return lexNumber
+	case '.', 'e', 'E':
+		return lexFloat
+	}
+
+	lx.backup()
+	lx.emit(itemInteger)
+	return lx.pop()
+}
+
+// lexDatetime consumes a Datetime, to a first approximation.
+// The parser validates that it matches one of the accepted formats.
+func lexDatetime(lx *lexer) stateFn {
+	r := lx.next()
+	if isDigit(r) {
+		return lexDatetime
+	}
+	switch r {
+	case '-', 'T', ':', '.', 'Z', '+':
+		return lexDatetime
+	}
+
+	lx.backup()
+	lx.emit(itemDatetime)
+	return lx.pop()
+}
+
+// lexNumberStart consumes either an integer or a float. It assumes that a sign
+// has already been read, but that *no* digits have been consumed.
+// lexNumberStart will move to the appropriate integer or float states.
+func lexNumberStart(lx *lexer) stateFn {
+	// We MUST see a digit. Even floats have to start with a digit.
+	r := lx.next()
+	if !isDigit(r) {
+		if r == '.' {
+			return lx.errorf("floats must start with a digit, not '.'")
+		}
+		return lx.errorf("expected a digit but got %q", r)
+	}
+	return lexNumber
+}
+
+// lexNumber consumes an integer or a float after seeing the first digit.
+func lexNumber(lx *lexer) stateFn {
+	r := lx.next()
+	if isDigit(r) {
+		return lexNumber
+	}
+	switch r {
+	case '_':
+		return lexNumber
+	case '.', 'e', 'E':
+		return lexFloat
+	}
+
+	lx.backup()
+	lx.emit(itemInteger)
+	return lx.pop()
+}
+
+// lexFloat consumes the elements of a float. It allows any sequence of
+// float-like characters, so floats emitted by the lexer are only a first
+// approximation and must be validated by the parser.
+func lexFloat(lx *lexer) stateFn {
+	r := lx.next()
+	if isDigit(r) {
+		return lexFloat
+	}
+	switch r {
+	case '_', '.', '-', '+', 'e', 'E':
+		return lexFloat
+	}
+
+	lx.backup()
+	lx.emit(itemFloat)
+	return lx.pop()
+}
+
+// lexBool consumes a bool string: 'true' or 'false.
+func lexBool(lx *lexer) stateFn {
+	var rs []rune
+	for {
+		r := lx.next()
+		if !unicode.IsLetter(r) {
+			lx.backup()
+			break
+		}
+		rs = append(rs, r)
+	}
+	s := string(rs)
+	switch s {
+	case "true", "false":
+		lx.emit(itemBool)
+		return lx.pop()
+	}
+	return lx.errorf("expected value but found %q instead", s)
+}
+
+// lexCommentStart begins the lexing of a comment. It will emit
+// itemCommentStart and consume no characters, passing control to lexComment.
+func lexCommentStart(lx *lexer) stateFn {
+	lx.ignore()
+	lx.emit(itemCommentStart)
+	return lexComment
+}
+
+// lexComment lexes an entire comment. It assumes that '#' has been consumed.
+// It will consume *up to* the first newline character, and pass control
+// back to the last state on the stack.
+func lexComment(lx *lexer) stateFn {
+	r := lx.peek()
+	if isNL(r) || r == eof {
+		lx.emit(itemText)
+		return lx.pop()
+	}
+	lx.next()
+	return lexComment
+}
+
+// lexSkip ignores all slurped input and moves on to the next state.
+func lexSkip(lx *lexer, nextState stateFn) stateFn {
+	return func(lx *lexer) stateFn {
+		lx.ignore()
+		return nextState
+	}
+}
+
+// isWhitespace returns true if `r` is a whitespace character according
+// to the spec.
+func isWhitespace(r rune) bool {
+	return r == '\t' || r == ' '
+}
+
+func isNL(r rune) bool {
+	return r == '\n' || r == '\r'
+}
+
+func isDigit(r rune) bool {
+	return r >= '0' && r <= '9'
+}
+
+func isHexadecimal(r rune) bool {
+	return (r >= '0' && r <= '9') ||
+		(r >= 'a' && r <= 'f') ||
+		(r >= 'A' && r <= 'F')
+}
+
+func isBareKeyChar(r rune) bool {
+	return (r >= 'A' && r <= 'Z') ||
+		(r >= 'a' && r <= 'z') ||
+		(r >= '0' && r <= '9') ||
+		r == '_' ||
+		r == '-'
+}
+
+func (itype itemType) String() string {
+	switch itype {
+	case itemError:
+		return "Error"
+	case itemNIL:
+		return "NIL"
+	case itemEOF:
+		return "EOF"
+	case itemText:
+		return "Text"
+	case itemString, itemRawString, itemMultilineString, itemRawMultilineString:
+		return "String"
+	case itemBool:
+		return "Bool"
+	case itemInteger:
+		return "Integer"
+	case itemFloat:
+		return "Float"
+	case itemDatetime:
+		return "DateTime"
+	case itemTableStart:
+		return "TableStart"
+	case itemTableEnd:
+		return "TableEnd"
+	case itemKeyStart:
+		return "KeyStart"
+	case itemArray:
+		return "Array"
+	case itemArrayEnd:
+		return "ArrayEnd"
+	case itemCommentStart:
+		return "CommentStart"
+	}
+	panic(fmt.Sprintf("BUG: Unknown type '%d'.", int(itype)))
+}
+
+func (item item) String() string {
+	return fmt.Sprintf("(%s, %s)", item.typ.String(), item.val)
+}
diff --git a/vendor/github.com/BurntSushi/toml/parse.go b/vendor/github.com/BurntSushi/toml/parse.go
new file mode 100644
index 0000000000..50869ef926
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/parse.go
@@ -0,0 +1,592 @@
+package toml
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+	"unicode"
+	"unicode/utf8"
+)
+
+type parser struct {
+	mapping map[string]interface{}
+	types   map[string]tomlType
+	lx      *lexer
+
+	// A list of keys in the order that they appear in the TOML data.
+	ordered []Key
+
+	// the full key for the current hash in scope
+	context Key
+
+	// the base key name for everything except hashes
+	currentKey string
+
+	// rough approximation of line number
+	approxLine int
+
+	// A map of 'key.group.names' to whether they were created implicitly.
+	implicits map[string]bool
+}
+
+type parseError string
+
+func (pe parseError) Error() string {
+	return string(pe)
+}
+
+func parse(data string) (p *parser, err error) {
+	defer func() {
+		if r := recover(); r != nil {
+			var ok bool
+			if err, ok = r.(parseError); ok {
+				return
+			}
+			panic(r)
+		}
+	}()
+
+	p = &parser{
+		mapping:   make(map[string]interface{}),
+		types:     make(map[string]tomlType),
+		lx:        lex(data),
+		ordered:   make([]Key, 0),
+		implicits: make(map[string]bool),
+	}
+	for {
+		item := p.next()
+		if item.typ == itemEOF {
+			break
+		}
+		p.topLevel(item)
+	}
+
+	return p, nil
+}
+
+func (p *parser) panicf(format string, v ...interface{}) {
+	msg := fmt.Sprintf("Near line %d (last key parsed '%s'): %s",
+		p.approxLine, p.current(), fmt.Sprintf(format, v...))
+	panic(parseError(msg))
+}
+
+func (p *parser) next() item {
+	it := p.lx.nextItem()
+	if it.typ == itemError {
+		p.panicf("%s", it.val)
+	}
+	return it
+}
+
+func (p *parser) bug(format string, v ...interface{}) {
+	panic(fmt.Sprintf("BUG: "+format+"\n\n", v...))
+}
+
+func (p *parser) expect(typ itemType) item {
+	it := p.next()
+	p.assertEqual(typ, it.typ)
+	return it
+}
+
+func (p *parser) assertEqual(expected, got itemType) {
+	if expected != got {
+		p.bug("Expected '%s' but got '%s'.", expected, got)
+	}
+}
+
+func (p *parser) topLevel(item item) {
+	switch item.typ {
+	case itemCommentStart:
+		p.approxLine = item.line
+		p.expect(itemText)
+	case itemTableStart:
+		kg := p.next()
+		p.approxLine = kg.line
+
+		var key Key
+		for ; kg.typ != itemTableEnd && kg.typ != itemEOF; kg = p.next() {
+			key = append(key, p.keyString(kg))
+		}
+		p.assertEqual(itemTableEnd, kg.typ)
+
+		p.establishContext(key, false)
+		p.setType("", tomlHash)
+		p.ordered = append(p.ordered, key)
+	case itemArrayTableStart:
+		kg := p.next()
+		p.approxLine = kg.line
+
+		var key Key
+		for ; kg.typ != itemArrayTableEnd && kg.typ != itemEOF; kg = p.next() {
+			key = append(key, p.keyString(kg))
+		}
+		p.assertEqual(itemArrayTableEnd, kg.typ)
+
+		p.establishContext(key, true)
+		p.setType("", tomlArrayHash)
+		p.ordered = append(p.ordered, key)
+	case itemKeyStart:
+		kname := p.next()
+		p.approxLine = kname.line
+		p.currentKey = p.keyString(kname)
+
+		val, typ := p.value(p.next())
+		p.setValue(p.currentKey, val)
+		p.setType(p.currentKey, typ)
+		p.ordered = append(p.ordered, p.context.add(p.currentKey))
+		p.currentKey = ""
+	default:
+		p.bug("Unexpected type at top level: %s", item.typ)
+	}
+}
+
+// Gets a string for a key (or part of a key in a table name).
+func (p *parser) keyString(it item) string {
+	switch it.typ {
+	case itemText:
+		return it.val
+	case itemString, itemMultilineString,
+		itemRawString, itemRawMultilineString:
+		s, _ := p.value(it)
+		return s.(string)
+	default:
+		p.bug("Unexpected key type: %s", it.typ)
+		panic("unreachable")
+	}
+}
+
+// value translates an expected value from the lexer into a Go value wrapped
+// as an empty interface.
+func (p *parser) value(it item) (interface{}, tomlType) {
+	switch it.typ {
+	case itemString:
+		return p.replaceEscapes(it.val), p.typeOfPrimitive(it)
+	case itemMultilineString:
+		trimmed := stripFirstNewline(stripEscapedWhitespace(it.val))
+		return p.replaceEscapes(trimmed), p.typeOfPrimitive(it)
+	case itemRawString:
+		return it.val, p.typeOfPrimitive(it)
+	case itemRawMultilineString:
+		return stripFirstNewline(it.val), p.typeOfPrimitive(it)
+	case itemBool:
+		switch it.val {
+		case "true":
+			return true, p.typeOfPrimitive(it)
+		case "false":
+			return false, p.typeOfPrimitive(it)
+		}
+		p.bug("Expected boolean value, but got '%s'.", it.val)
+	case itemInteger:
+		if !numUnderscoresOK(it.val) {
+			p.panicf("Invalid integer %q: underscores must be surrounded by digits",
+				it.val)
+		}
+		val := strings.Replace(it.val, "_", "", -1)
+		num, err := strconv.ParseInt(val, 10, 64)
+		if err != nil {
+			// Distinguish integer values. Normally, it'd be a bug if the lexer
+			// provides an invalid integer, but it's possible that the number is
+			// out of range of valid values (which the lexer cannot determine).
+			// So mark the former as a bug but the latter as a legitimate user
+			// error.
+			if e, ok := err.(*strconv.NumError); ok &&
+				e.Err == strconv.ErrRange {
+
+				p.panicf("Integer '%s' is out of the range of 64-bit "+
+					"signed integers.", it.val)
+			} else {
+				p.bug("Expected integer value, but got '%s'.", it.val)
+			}
+		}
+		return num, p.typeOfPrimitive(it)
+	case itemFloat:
+		parts := strings.FieldsFunc(it.val, func(r rune) bool {
+			switch r {
+			case '.', 'e', 'E':
+				return true
+			}
+			return false
+		})
+		for _, part := range parts {
+			if !numUnderscoresOK(part) {
+				p.panicf("Invalid float %q: underscores must be "+
+					"surrounded by digits", it.val)
+			}
+		}
+		if !numPeriodsOK(it.val) {
+			// As a special case, numbers like '123.' or '1.e2',
+			// which are valid as far as Go/strconv are concerned,
+			// must be rejected because TOML says that a fractional
+			// part consists of '.' followed by 1+ digits.
+			p.panicf("Invalid float %q: '.' must be followed "+
+				"by one or more digits", it.val)
+		}
+		val := strings.Replace(it.val, "_", "", -1)
+		num, err := strconv.ParseFloat(val, 64)
+		if err != nil {
+			if e, ok := err.(*strconv.NumError); ok &&
+				e.Err == strconv.ErrRange {
+
+				p.panicf("Float '%s' is out of the range of 64-bit "+
+					"IEEE-754 floating-point numbers.", it.val)
+			} else {
+				p.panicf("Invalid float value: %q", it.val)
+			}
+		}
+		return num, p.typeOfPrimitive(it)
+	case itemDatetime:
+		var t time.Time
+		var ok bool
+		var err error
+		for _, format := range []string{
+			"2006-01-02T15:04:05Z07:00",
+			"2006-01-02T15:04:05",
+			"2006-01-02",
+		} {
+			t, err = time.ParseInLocation(format, it.val, time.Local)
+			if err == nil {
+				ok = true
+				break
+			}
+		}
+		if !ok {
+			p.panicf("Invalid TOML Datetime: %q.", it.val)
+		}
+		return t, p.typeOfPrimitive(it)
+	case itemArray:
+		array := make([]interface{}, 0)
+		types := make([]tomlType, 0)
+
+		for it = p.next(); it.typ != itemArrayEnd; it = p.next() {
+			if it.typ == itemCommentStart {
+				p.expect(itemText)
+				continue
+			}
+
+			val, typ := p.value(it)
+			array = append(array, val)
+			types = append(types, typ)
+		}
+		return array, p.typeOfArray(types)
+	case itemInlineTableStart:
+		var (
+			hash         = make(map[string]interface{})
+			outerContext = p.context
+			outerKey     = p.currentKey
+		)
+
+		p.context = append(p.context, p.currentKey)
+		p.currentKey = ""
+		for it := p.next(); it.typ != itemInlineTableEnd; it = p.next() {
+			if it.typ != itemKeyStart {
+				p.bug("Expected key start but instead found %q, around line %d",
+					it.val, p.approxLine)
+			}
+			if it.typ == itemCommentStart {
+				p.expect(itemText)
+				continue
+			}
+
+			// retrieve key
+			k := p.next()
+			p.approxLine = k.line
+			kname := p.keyString(k)
+
+			// retrieve value
+			p.currentKey = kname
+			val, typ := p.value(p.next())
+			// make sure we keep metadata up to date
+			p.setType(kname, typ)
+			p.ordered = append(p.ordered, p.context.add(p.currentKey))
+			hash[kname] = val
+		}
+		p.context = outerContext
+		p.currentKey = outerKey
+		return hash, tomlHash
+	}
+	p.bug("Unexpected value type: %s", it.typ)
+	panic("unreachable")
+}
+
+// numUnderscoresOK checks whether each underscore in s is surrounded by
+// characters that are not underscores.
+func numUnderscoresOK(s string) bool {
+	accept := false
+	for _, r := range s {
+		if r == '_' {
+			if !accept {
+				return false
+			}
+			accept = false
+			continue
+		}
+		accept = true
+	}
+	return accept
+}
+
+// numPeriodsOK checks whether every period in s is followed by a digit.
+func numPeriodsOK(s string) bool {
+	period := false
+	for _, r := range s {
+		if period && !isDigit(r) {
+			return false
+		}
+		period = r == '.'
+	}
+	return !period
+}
+
+// establishContext sets the current context of the parser,
+// where the context is either a hash or an array of hashes. Which one is
+// set depends on the value of the `array` parameter.
+//
+// Establishing the context also makes sure that the key isn't a duplicate, and
+// will create implicit hashes automatically.
+func (p *parser) establishContext(key Key, array bool) {
+	var ok bool
+
+	// Always start at the top level and drill down for our context.
+	hashContext := p.mapping
+	keyContext := make(Key, 0)
+
+	// We only need implicit hashes for key[0:-1]
+	for _, k := range key[0 : len(key)-1] {
+		_, ok = hashContext[k]
+		keyContext = append(keyContext, k)
+
+		// No key? Make an implicit hash and move on.
+		if !ok {
+			p.addImplicit(keyContext)
+			hashContext[k] = make(map[string]interface{})
+		}
+
+		// If the hash context is actually an array of tables, then set
+		// the hash context to the last element in that array.
+		//
+		// Otherwise, it better be a table, since this MUST be a key group (by
+		// virtue of it not being the last element in a key).
+		switch t := hashContext[k].(type) {
+		case []map[string]interface{}:
+			hashContext = t[len(t)-1]
+		case map[string]interface{}:
+			hashContext = t
+		default:
+			p.panicf("Key '%s' was already created as a hash.", keyContext)
+		}
+	}
+
+	p.context = keyContext
+	if array {
+		// If this is the first element for this array, then allocate a new
+		// list of tables for it.
+		k := key[len(key)-1]
+		if _, ok := hashContext[k]; !ok {
+			hashContext[k] = make([]map[string]interface{}, 0, 5)
+		}
+
+		// Add a new table. But make sure the key hasn't already been used
+		// for something else.
+		if hash, ok := hashContext[k].([]map[string]interface{}); ok {
+			hashContext[k] = append(hash, make(map[string]interface{}))
+		} else {
+			p.panicf("Key '%s' was already created and cannot be used as "+
+				"an array.", keyContext)
+		}
+	} else {
+		p.setValue(key[len(key)-1], make(map[string]interface{}))
+	}
+	p.context = append(p.context, key[len(key)-1])
+}
+
+// setValue sets the given key to the given value in the current context.
+// It will make sure that the key hasn't already been defined, account for
+// implicit key groups.
+func (p *parser) setValue(key string, value interface{}) {
+	var tmpHash interface{}
+	var ok bool
+
+	hash := p.mapping
+	keyContext := make(Key, 0)
+	for _, k := range p.context {
+		keyContext = append(keyContext, k)
+		if tmpHash, ok = hash[k]; !ok {
+			p.bug("Context for key '%s' has not been established.", keyContext)
+		}
+		switch t := tmpHash.(type) {
+		case []map[string]interface{}:
+			// The context is a table of hashes. Pick the most recent table
+			// defined as the current hash.
+			hash = t[len(t)-1]
+		case map[string]interface{}:
+			hash = t
+		default:
+			p.bug("Expected hash to have type 'map[string]interface{}', but "+
+				"it has '%T' instead.", tmpHash)
+		}
+	}
+	keyContext = append(keyContext, key)
+
+	if _, ok := hash[key]; ok {
+		// Typically, if the given key has already been set, then we have
+		// to raise an error since duplicate keys are disallowed. However,
+		// it's possible that a key was previously defined implicitly. In this
+		// case, it is allowed to be redefined concretely. (See the
+		// `tests/valid/implicit-and-explicit-after.toml` test in `toml-test`.)
+		//
+		// But we have to make sure to stop marking it as an implicit. (So that
+		// another redefinition provokes an error.)
+		//
+		// Note that since it has already been defined (as a hash), we don't
+		// want to overwrite it. So our business is done.
+		if p.isImplicit(keyContext) {
+			p.removeImplicit(keyContext)
+			return
+		}
+
+		// Otherwise, we have a concrete key trying to override a previous
+		// key, which is *always* wrong.
+		p.panicf("Key '%s' has already been defined.", keyContext)
+	}
+	hash[key] = value
+}
+
+// setType sets the type of a particular value at a given key.
+// It should be called immediately AFTER setValue.
+//
+// Note that if `key` is empty, then the type given will be applied to the
+// current context (which is either a table or an array of tables).
+func (p *parser) setType(key string, typ tomlType) {
+	keyContext := make(Key, 0, len(p.context)+1)
+	for _, k := range p.context {
+		keyContext = append(keyContext, k)
+	}
+	if len(key) > 0 { // allow type setting for hashes
+		keyContext = append(keyContext, key)
+	}
+	p.types[keyContext.String()] = typ
+}
+
+// addImplicit sets the given Key as having been created implicitly.
+func (p *parser) addImplicit(key Key) {
+	p.implicits[key.String()] = true
+}
+
+// removeImplicit stops tagging the given key as having been implicitly
+// created.
+func (p *parser) removeImplicit(key Key) {
+	p.implicits[key.String()] = false
+}
+
+// isImplicit returns true if the key group pointed to by the key was created
+// implicitly.
+func (p *parser) isImplicit(key Key) bool {
+	return p.implicits[key.String()]
+}
+
+// current returns the full key name of the current context.
+func (p *parser) current() string {
+	if len(p.currentKey) == 0 {
+		return p.context.String()
+	}
+	if len(p.context) == 0 {
+		return p.currentKey
+	}
+	return fmt.Sprintf("%s.%s", p.context, p.currentKey)
+}
+
+func stripFirstNewline(s string) string {
+	if len(s) == 0 || s[0] != '\n' {
+		return s
+	}
+	return s[1:]
+}
+
+func stripEscapedWhitespace(s string) string {
+	esc := strings.Split(s, "\\\n")
+	if len(esc) > 1 {
+		for i := 1; i < len(esc); i++ {
+			esc[i] = strings.TrimLeftFunc(esc[i], unicode.IsSpace)
+		}
+	}
+	return strings.Join(esc, "")
+}
+
+func (p *parser) replaceEscapes(str string) string {
+	var replaced []rune
+	s := []byte(str)
+	r := 0
+	for r < len(s) {
+		if s[r] != '\\' {
+			c, size := utf8.DecodeRune(s[r:])
+			r += size
+			replaced = append(replaced, c)
+			continue
+		}
+		r += 1
+		if r >= len(s) {
+			p.bug("Escape sequence at end of string.")
+			return ""
+		}
+		switch s[r] {
+		default:
+			p.bug("Expected valid escape code after \\, but got %q.", s[r])
+			return ""
+		case 'b':
+			replaced = append(replaced, rune(0x0008))
+			r += 1
+		case 't':
+			replaced = append(replaced, rune(0x0009))
+			r += 1
+		case 'n':
+			replaced = append(replaced, rune(0x000A))
+			r += 1
+		case 'f':
+			replaced = append(replaced, rune(0x000C))
+			r += 1
+		case 'r':
+			replaced = append(replaced, rune(0x000D))
+			r += 1
+		case '"':
+			replaced = append(replaced, rune(0x0022))
+			r += 1
+		case '\\':
+			replaced = append(replaced, rune(0x005C))
+			r += 1
+		case 'u':
+			// At this point, we know we have a Unicode escape of the form
+			// `uXXXX` at [r, r+5). (Because the lexer guarantees this
+			// for us.)
+			escaped := p.asciiEscapeToUnicode(s[r+1 : r+5])
+			replaced = append(replaced, escaped)
+			r += 5
+		case 'U':
+			// At this point, we know we have a Unicode escape of the form
+			// `uXXXX` at [r, r+9). (Because the lexer guarantees this
+			// for us.)
+			escaped := p.asciiEscapeToUnicode(s[r+1 : r+9])
+			replaced = append(replaced, escaped)
+			r += 9
+		}
+	}
+	return string(replaced)
+}
+
+func (p *parser) asciiEscapeToUnicode(bs []byte) rune {
+	s := string(bs)
+	hex, err := strconv.ParseUint(strings.ToLower(s), 16, 32)
+	if err != nil {
+		p.bug("Could not parse '%s' as a hexadecimal number, but the "+
+			"lexer claims it's OK: %s", s, err)
+	}
+	if !utf8.ValidRune(rune(hex)) {
+		p.panicf("Escaped character '\\u%s' is not valid UTF-8.", s)
+	}
+	return rune(hex)
+}
+
+func isStringType(ty itemType) bool {
+	return ty == itemString || ty == itemMultilineString ||
+		ty == itemRawString || ty == itemRawMultilineString
+}
diff --git a/vendor/github.com/BurntSushi/toml/type_check.go b/vendor/github.com/BurntSushi/toml/type_check.go
new file mode 100644
index 0000000000..c73f8afc1a
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/type_check.go
@@ -0,0 +1,91 @@
+package toml
+
+// tomlType represents any Go type that corresponds to a TOML type.
+// While the first draft of the TOML spec has a simplistic type system that
+// probably doesn't need this level of sophistication, we seem to be militating
+// toward adding real composite types.
+type tomlType interface {
+	typeString() string
+}
+
+// typeEqual accepts any two types and returns true if they are equal.
+func typeEqual(t1, t2 tomlType) bool {
+	if t1 == nil || t2 == nil {
+		return false
+	}
+	return t1.typeString() == t2.typeString()
+}
+
+func typeIsHash(t tomlType) bool {
+	return typeEqual(t, tomlHash) || typeEqual(t, tomlArrayHash)
+}
+
+type tomlBaseType string
+
+func (btype tomlBaseType) typeString() string {
+	return string(btype)
+}
+
+func (btype tomlBaseType) String() string {
+	return btype.typeString()
+}
+
+var (
+	tomlInteger   tomlBaseType = "Integer"
+	tomlFloat     tomlBaseType = "Float"
+	tomlDatetime  tomlBaseType = "Datetime"
+	tomlString    tomlBaseType = "String"
+	tomlBool      tomlBaseType = "Bool"
+	tomlArray     tomlBaseType = "Array"
+	tomlHash      tomlBaseType = "Hash"
+	tomlArrayHash tomlBaseType = "ArrayHash"
+)
+
+// typeOfPrimitive returns a tomlType of any primitive value in TOML.
+// Primitive values are: Integer, Float, Datetime, String and Bool.
+//
+// Passing a lexer item other than the following will cause a BUG message
+// to occur: itemString, itemBool, itemInteger, itemFloat, itemDatetime.
+func (p *parser) typeOfPrimitive(lexItem item) tomlType {
+	switch lexItem.typ {
+	case itemInteger:
+		return tomlInteger
+	case itemFloat:
+		return tomlFloat
+	case itemDatetime:
+		return tomlDatetime
+	case itemString:
+		return tomlString
+	case itemMultilineString:
+		return tomlString
+	case itemRawString:
+		return tomlString
+	case itemRawMultilineString:
+		return tomlString
+	case itemBool:
+		return tomlBool
+	}
+	p.bug("Cannot infer primitive type of lex item '%s'.", lexItem)
+	panic("unreachable")
+}
+
+// typeOfArray returns a tomlType for an array given a list of types of its
+// values.
+//
+// In the current spec, if an array is homogeneous, then its type is always
+// "Array". If the array is not homogeneous, an error is generated.
+func (p *parser) typeOfArray(types []tomlType) tomlType {
+	// Empty arrays are cool.
+	if len(types) == 0 {
+		return tomlArray
+	}
+
+	theType := types[0]
+	for _, t := range types[1:] {
+		if !typeEqual(theType, t) {
+			p.panicf("Array contains values of type '%s' and '%s', but "+
+				"arrays must be homogeneous.", theType, t)
+		}
+	}
+	return tomlArray
+}
diff --git a/vendor/github.com/BurntSushi/toml/type_fields.go b/vendor/github.com/BurntSushi/toml/type_fields.go
new file mode 100644
index 0000000000..608997c22f
--- /dev/null
+++ b/vendor/github.com/BurntSushi/toml/type_fields.go
@@ -0,0 +1,242 @@
+package toml
+
+// Struct field handling is adapted from code in encoding/json:
+//
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the Go distribution.
+
+import (
+	"reflect"
+	"sort"
+	"sync"
+)
+
+// A field represents a single field found in a struct.
+type field struct {
+	name  string       // the name of the field (`toml` tag included)
+	tag   bool         // whether field has a `toml` tag
+	index []int        // represents the depth of an anonymous field
+	typ   reflect.Type // the type of the field
+}
+
+// byName sorts field by name, breaking ties with depth,
+// then breaking ties with "name came from toml tag", then
+// breaking ties with index sequence.
+type byName []field
+
+func (x byName) Len() int { return len(x) }
+
+func (x byName) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x byName) Less(i, j int) bool {
+	if x[i].name != x[j].name {
+		return x[i].name < x[j].name
+	}
+	if len(x[i].index) != len(x[j].index) {
+		return len(x[i].index) < len(x[j].index)
+	}
+	if x[i].tag != x[j].tag {
+		return x[i].tag
+	}
+	return byIndex(x).Less(i, j)
+}
+
+// byIndex sorts field by index sequence.
+type byIndex []field
+
+func (x byIndex) Len() int { return len(x) }
+
+func (x byIndex) Swap(i, j int) { x[i], x[j] = x[j], x[i] }
+
+func (x byIndex) Less(i, j int) bool {
+	for k, xik := range x[i].index {
+		if k >= len(x[j].index) {
+			return false
+		}
+		if xik != x[j].index[k] {
+			return xik < x[j].index[k]
+		}
+	}
+	return len(x[i].index) < len(x[j].index)
+}
+
+// typeFields returns a list of fields that TOML should recognize for the given
+// type. The algorithm is breadth-first search over the set of structs to
+// include - the top struct and then any reachable anonymous structs.
+func typeFields(t reflect.Type) []field {
+	// Anonymous fields to explore at the current level and the next.
+	current := []field{}
+	next := []field{{typ: t}}
+
+	// Count of queued names for current level and the next.
+	count := map[reflect.Type]int{}
+	nextCount := map[reflect.Type]int{}
+
+	// Types already visited at an earlier level.
+	visited := map[reflect.Type]bool{}
+
+	// Fields found.
+	var fields []field
+
+	for len(next) > 0 {
+		current, next = next, current[:0]
+		count, nextCount = nextCount, map[reflect.Type]int{}
+
+		for _, f := range current {
+			if visited[f.typ] {
+				continue
+			}
+			visited[f.typ] = true
+
+			// Scan f.typ for fields to include.
+			for i := 0; i < f.typ.NumField(); i++ {
+				sf := f.typ.Field(i)
+				if sf.PkgPath != "" && !sf.Anonymous { // unexported
+					continue
+				}
+				opts := getOptions(sf.Tag)
+				if opts.skip {
+					continue
+				}
+				index := make([]int, len(f.index)+1)
+				copy(index, f.index)
+				index[len(f.index)] = i
+
+				ft := sf.Type
+				if ft.Name() == "" && ft.Kind() == reflect.Ptr {
+					// Follow pointer.
+					ft = ft.Elem()
+				}
+
+				// Record found field and index sequence.
+				if opts.name != "" || !sf.Anonymous || ft.Kind() != reflect.Struct {
+					tagged := opts.name != ""
+					name := opts.name
+					if name == "" {
+						name = sf.Name
+					}
+					fields = append(fields, field{name, tagged, index, ft})
+					if count[f.typ] > 1 {
+						// If there were multiple instances, add a second,
+						// so that the annihilation code will see a duplicate.
+						// It only cares about the distinction between 1 or 2,
+						// so don't bother generating any more copies.
+						fields = append(fields, fields[len(fields)-1])
+					}
+					continue
+				}
+
+				// Record new anonymous struct to explore in next round.
+				nextCount[ft]++
+				if nextCount[ft] == 1 {
+					f := field{name: ft.Name(), index: index, typ: ft}
+					next = append(next, f)
+				}
+			}
+		}
+	}
+
+	sort.Sort(byName(fields))
+
+	// Delete all fields that are hidden by the Go rules for embedded fields,
+	// except that fields with TOML tags are promoted.
+
+	// The fields are sorted in primary order of name, secondary order
+	// of field index length. Loop over names; for each name, delete
+	// hidden fields by choosing the one dominant field that survives.
+	out := fields[:0]
+	for advance, i := 0, 0; i < len(fields); i += advance {
+		// One iteration per name.
+		// Find the sequence of fields with the name of this first field.
+		fi := fields[i]
+		name := fi.name
+		for advance = 1; i+advance < len(fields); advance++ {
+			fj := fields[i+advance]
+			if fj.name != name {
+				break
+			}
+		}
+		if advance == 1 { // Only one field with this name
+			out = append(out, fi)
+			continue
+		}
+		dominant, ok := dominantField(fields[i : i+advance])
+		if ok {
+			out = append(out, dominant)
+		}
+	}
+
+	fields = out
+	sort.Sort(byIndex(fields))
+
+	return fields
+}
+
+// dominantField looks through the fields, all of which are known to
+// have the same name, to find the single field that dominates the
+// others using Go's embedding rules, modified by the presence of
+// TOML tags. If there are multiple top-level fields, the boolean
+// will be false: This condition is an error in Go and we skip all
+// the fields.
+func dominantField(fields []field) (field, bool) {
+	// The fields are sorted in increasing index-length order. The winner
+	// must therefore be one with the shortest index length. Drop all
+	// longer entries, which is easy: just truncate the slice.
+	length := len(fields[0].index)
+	tagged := -1 // Index of first tagged field.
+	for i, f := range fields {
+		if len(f.index) > length {
+			fields = fields[:i]
+			break
+		}
+		if f.tag {
+			if tagged >= 0 {
+				// Multiple tagged fields at the same level: conflict.
+				// Return no field.
+				return field{}, false
+			}
+			tagged = i
+		}
+	}
+	if tagged >= 0 {
+		return fields[tagged], true
+	}
+	// All remaining fields have the same length. If there's more than one,
+	// we have a conflict (two fields named "X" at the same level) and we
+	// return no field.
+	if len(fields) > 1 {
+		return field{}, false
+	}
+	return fields[0], true
+}
+
+var fieldCache struct {
+	sync.RWMutex
+	m map[reflect.Type][]field
+}
+
+// cachedTypeFields is like typeFields but uses a cache to avoid repeated work.
+func cachedTypeFields(t reflect.Type) []field {
+	fieldCache.RLock()
+	f := fieldCache.m[t]
+	fieldCache.RUnlock()
+	if f != nil {
+		return f
+	}
+
+	// Compute fields without lock.
+	// Might duplicate effort but won't hold other computations back.
+	f = typeFields(t)
+	if f == nil {
+		f = []field{}
+	}
+
+	fieldCache.Lock()
+	if fieldCache.m == nil {
+		fieldCache.m = map[reflect.Type][]field{}
+	}
+	fieldCache.m[t] = f
+	fieldCache.Unlock()
+	return f
+}
diff --git a/vendor/github.com/couchbase/gomemcached/LICENSE b/vendor/github.com/couchbase/gomemcached/LICENSE
new file mode 100644
index 0000000000..b01ef80261
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2013 Dustin Sallings
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/vendor/github.com/couchbase/gomemcached/client/mc.go b/vendor/github.com/couchbase/gomemcached/client/mc.go
new file mode 100644
index 0000000000..bd1433ba28
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/client/mc.go
@@ -0,0 +1,1074 @@
+// Package memcached provides a memcached binary protocol client.
+package memcached
+
+import (
+	"encoding/binary"
+	"fmt"
+	"github.com/couchbase/gomemcached"
+	"github.com/couchbase/goutils/logging"
+	"github.com/couchbase/goutils/scramsha"
+	"github.com/pkg/errors"
+	"io"
+	"math"
+	"net"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type ClientIface interface {
+	Add(vb uint16, key string, flags int, exp int, body []byte) (*gomemcached.MCResponse, error)
+	Append(vb uint16, key string, data []byte) (*gomemcached.MCResponse, error)
+	Auth(user, pass string) (*gomemcached.MCResponse, error)
+	AuthList() (*gomemcached.MCResponse, error)
+	AuthPlain(user, pass string) (*gomemcached.MCResponse, error)
+	AuthScramSha(user, pass string) (*gomemcached.MCResponse, error)
+	CASNext(vb uint16, k string, exp int, state *CASState) bool
+	CAS(vb uint16, k string, f CasFunc, initexp int) (*gomemcached.MCResponse, error)
+	Close() error
+	Decr(vb uint16, key string, amt, def uint64, exp int) (uint64, error)
+	Del(vb uint16, key string) (*gomemcached.MCResponse, error)
+	EnableMutationToken() (*gomemcached.MCResponse, error)
+	Get(vb uint16, key string) (*gomemcached.MCResponse, error)
+	GetSubdoc(vb uint16, key string, subPaths []string) (*gomemcached.MCResponse, error)
+	GetAndTouch(vb uint16, key string, exp int) (*gomemcached.MCResponse, error)
+	GetBulk(vb uint16, keys []string, rv map[string]*gomemcached.MCResponse, subPaths []string) error
+	GetMeta(vb uint16, key string) (*gomemcached.MCResponse, error)
+	GetRandomDoc() (*gomemcached.MCResponse, error)
+	Hijack() io.ReadWriteCloser
+	Incr(vb uint16, key string, amt, def uint64, exp int) (uint64, error)
+	Observe(vb uint16, key string) (result ObserveResult, err error)
+	ObserveSeq(vb uint16, vbuuid uint64) (result *ObserveSeqResult, err error)
+	Receive() (*gomemcached.MCResponse, error)
+	ReceiveWithDeadline(deadline time.Time) (*gomemcached.MCResponse, error)
+	Send(req *gomemcached.MCRequest) (rv *gomemcached.MCResponse, err error)
+	Set(vb uint16, key string, flags int, exp int, body []byte) (*gomemcached.MCResponse, error)
+	SetKeepAliveOptions(interval time.Duration)
+	SetReadDeadline(t time.Time)
+	SetDeadline(t time.Time)
+	SelectBucket(bucket string) (*gomemcached.MCResponse, error)
+	SetCas(vb uint16, key string, flags int, exp int, cas uint64, body []byte) (*gomemcached.MCResponse, error)
+	Stats(key string) ([]StatValue, error)
+	StatsMap(key string) (map[string]string, error)
+	StatsMapForSpecifiedStats(key string, statsMap map[string]string) error
+	Transmit(req *gomemcached.MCRequest) error
+	TransmitWithDeadline(req *gomemcached.MCRequest, deadline time.Time) error
+	TransmitResponse(res *gomemcached.MCResponse) error
+
+	// UprFeed Related
+	NewUprFeed() (*UprFeed, error)
+	NewUprFeedIface() (UprFeedIface, error)
+	NewUprFeedWithConfig(ackByClient bool) (*UprFeed, error)
+	NewUprFeedWithConfigIface(ackByClient bool) (UprFeedIface, error)
+	UprGetFailoverLog(vb []uint16) (map[uint16]*FailoverLog, error)
+}
+
+const bufsize = 1024
+
+var UnHealthy uint32 = 0
+var Healthy uint32 = 1
+
+type Features []Feature
+type Feature uint16
+
+const FeatureMutationToken = Feature(0x04)
+const FeatureXattr = Feature(0x06)
+const FeatureDataType = Feature(0x0b)
+
+// The Client itself.
+type Client struct {
+	conn io.ReadWriteCloser
+	// use uint32 type so that it can be accessed through atomic APIs
+	healthy uint32
+	opaque  uint32
+
+	hdrBuf []byte
+}
+
+var (
+	DefaultDialTimeout = time.Duration(0) // No timeout
+
+	DefaultWriteTimeout = time.Duration(0) // No timeout
+
+	dialFun = func(prot, dest string) (net.Conn, error) {
+		return net.DialTimeout(prot, dest, DefaultDialTimeout)
+	}
+)
+
+// Connect to a memcached server.
+func Connect(prot, dest string) (rv *Client, err error) {
+	conn, err := dialFun(prot, dest)
+	if err != nil {
+		return nil, err
+	}
+	return Wrap(conn)
+}
+
+func SetDefaultTimeouts(dial, read, write time.Duration) {
+	DefaultDialTimeout = dial
+	DefaultWriteTimeout = write
+}
+
+func SetDefaultDialTimeout(dial time.Duration) {
+	DefaultDialTimeout = dial
+}
+
+func (c *Client) SetKeepAliveOptions(interval time.Duration) {
+	c.conn.(*net.TCPConn).SetKeepAlive(true)
+	c.conn.(*net.TCPConn).SetKeepAlivePeriod(interval)
+}
+
+func (c *Client) SetReadDeadline(t time.Time) {
+	c.conn.(*net.TCPConn).SetReadDeadline(t)
+}
+
+func (c *Client) SetDeadline(t time.Time) {
+	c.conn.(*net.TCPConn).SetDeadline(t)
+}
+
+// Wrap an existing transport.
+func Wrap(rwc io.ReadWriteCloser) (rv *Client, err error) {
+	client := &Client{
+		conn:   rwc,
+		hdrBuf: make([]byte, gomemcached.HDR_LEN),
+		opaque: uint32(1),
+	}
+	client.setHealthy(true)
+	return client, nil
+}
+
+// Close the connection when you're done.
+func (c *Client) Close() error {
+	return c.conn.Close()
+}
+
+// IsHealthy returns true unless the client is belived to have
+// difficulty communicating to its server.
+//
+// This is useful for connection pools where we want to
+// non-destructively determine that a connection may be reused.
+func (c Client) IsHealthy() bool {
+	healthyState := atomic.LoadUint32(&c.healthy)
+	return healthyState == Healthy
+}
+
+// Send a custom request and get the response.
+func (c *Client) Send(req *gomemcached.MCRequest) (rv *gomemcached.MCResponse, err error) {
+	err = c.Transmit(req)
+	if err != nil {
+		return
+	}
+	resp, _, err := getResponse(c.conn, c.hdrBuf)
+	c.setHealthy(!gomemcached.IsFatal(err))
+	return resp, err
+}
+
+// Transmit send a request, but does not wait for a response.
+func (c *Client) Transmit(req *gomemcached.MCRequest) error {
+	if DefaultWriteTimeout > 0 {
+		c.conn.(net.Conn).SetWriteDeadline(time.Now().Add(DefaultWriteTimeout))
+	}
+	_, err := transmitRequest(c.conn, req)
+	// clear write deadline to avoid interference with future write operations
+	if DefaultWriteTimeout > 0 {
+		c.conn.(net.Conn).SetWriteDeadline(time.Time{})
+	}
+	if err != nil {
+		c.setHealthy(false)
+	}
+	return err
+}
+
+func (c *Client) TransmitWithDeadline(req *gomemcached.MCRequest, deadline time.Time) error {
+	c.conn.(net.Conn).SetWriteDeadline(deadline)
+
+	_, err := transmitRequest(c.conn, req)
+
+	// clear write deadline to avoid interference with future write operations
+	c.conn.(net.Conn).SetWriteDeadline(time.Time{})
+
+	if err != nil {
+		c.setHealthy(false)
+	}
+	return err
+}
+
+// TransmitResponse send a response, does not wait.
+func (c *Client) TransmitResponse(res *gomemcached.MCResponse) error {
+	if DefaultWriteTimeout > 0 {
+		c.conn.(net.Conn).SetWriteDeadline(time.Now().Add(DefaultWriteTimeout))
+	}
+	_, err := transmitResponse(c.conn, res)
+	// clear write deadline to avoid interference with future write operations
+	if DefaultWriteTimeout > 0 {
+		c.conn.(net.Conn).SetWriteDeadline(time.Time{})
+	}
+	if err != nil {
+		c.setHealthy(false)
+	}
+	return err
+}
+
+// Receive a response
+func (c *Client) Receive() (*gomemcached.MCResponse, error) {
+	resp, _, err := getResponse(c.conn, c.hdrBuf)
+	if err != nil && resp.Status != gomemcached.KEY_ENOENT && resp.Status != gomemcached.EBUSY {
+		c.setHealthy(false)
+	}
+	return resp, err
+}
+
+func (c *Client) ReceiveWithDeadline(deadline time.Time) (*gomemcached.MCResponse, error) {
+	c.conn.(net.Conn).SetReadDeadline(deadline)
+
+	resp, _, err := getResponse(c.conn, c.hdrBuf)
+
+	// Clear read deadline to avoid interference with future read operations.
+	c.conn.(net.Conn).SetReadDeadline(time.Time{})
+
+	if err != nil && resp.Status != gomemcached.KEY_ENOENT && resp.Status != gomemcached.EBUSY {
+		c.setHealthy(false)
+	}
+	return resp, err
+}
+
+func appendMutationToken(bytes []byte) []byte {
+	bytes = append(bytes, 0, 0)
+	binary.BigEndian.PutUint16(bytes[len(bytes)-2:], uint16(0x04))
+	return bytes
+}
+
+//Send a hello command to enable MutationTokens
+func (c *Client) EnableMutationToken() (*gomemcached.MCResponse, error) {
+	var payload []byte
+	payload = appendMutationToken(payload)
+
+	return c.Send(&gomemcached.MCRequest{
+		Opcode: gomemcached.HELLO,
+		Key:    []byte("GoMemcached"),
+		Body:   payload,
+	})
+
+}
+
+//Send a hello command to enable specific features
+func (c *Client) EnableFeatures(features Features) (*gomemcached.MCResponse, error) {
+	var payload []byte
+
+	for _, feature := range features {
+		payload = append(payload, 0, 0)
+		binary.BigEndian.PutUint16(payload[len(payload)-2:], uint16(feature))
+	}
+
+	return c.Send(&gomemcached.MCRequest{
+		Opcode: gomemcached.HELLO,
+		Key:    []byte("GoMemcached"),
+		Body:   payload,
+	})
+
+}
+
+// Get the value for a key.
+func (c *Client) Get(vb uint16, key string) (*gomemcached.MCResponse, error) {
+	return c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.GET,
+		VBucket: vb,
+		Key:     []byte(key),
+	})
+}
+
+// Get the xattrs, doc value for the input key
+func (c *Client) GetSubdoc(vb uint16, key string, subPaths []string) (*gomemcached.MCResponse, error) {
+
+	extraBuf, valueBuf := GetSubDocVal(subPaths)
+	res, err := c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.SUBDOC_MULTI_LOOKUP,
+		VBucket: vb,
+		Key:     []byte(key),
+		Extras:  extraBuf,
+		Body:    valueBuf,
+	})
+
+	if err != nil && IfResStatusError(res) {
+		return res, err
+	}
+	return res, nil
+}
+
+// Get the value for a key, and update expiry
+func (c *Client) GetAndTouch(vb uint16, key string, exp int) (*gomemcached.MCResponse, error) {
+	extraBuf := make([]byte, 4)
+	binary.BigEndian.PutUint32(extraBuf[0:], uint32(exp))
+	return c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.GAT,
+		VBucket: vb,
+		Key:     []byte(key),
+		Extras:  extraBuf,
+	})
+}
+
+// Get metadata for a key
+func (c *Client) GetMeta(vb uint16, key string) (*gomemcached.MCResponse, error) {
+	return c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.GET_META,
+		VBucket: vb,
+		Key:     []byte(key),
+	})
+}
+
+// Del deletes a key.
+func (c *Client) Del(vb uint16, key string) (*gomemcached.MCResponse, error) {
+	return c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.DELETE,
+		VBucket: vb,
+		Key:     []byte(key)})
+}
+
+// Get a random document
+func (c *Client) GetRandomDoc() (*gomemcached.MCResponse, error) {
+	return c.Send(&gomemcached.MCRequest{
+		Opcode: 0xB6,
+	})
+}
+
+// AuthList lists SASL auth mechanisms.
+func (c *Client) AuthList() (*gomemcached.MCResponse, error) {
+	return c.Send(&gomemcached.MCRequest{
+		Opcode: gomemcached.SASL_LIST_MECHS})
+}
+
+// Auth performs SASL PLAIN authentication against the server.
+func (c *Client) Auth(user, pass string) (*gomemcached.MCResponse, error) {
+	res, err := c.AuthList()
+
+	if err != nil {
+		return res, err
+	}
+
+	authMech := string(res.Body)
+	if strings.Index(authMech, "PLAIN") != -1 {
+		return c.AuthPlain(user, pass)
+	}
+	return nil, fmt.Errorf("auth mechanism PLAIN not supported")
+}
+
+// AuthScramSha performs SCRAM-SHA authentication against the server.
+func (c *Client) AuthScramSha(user, pass string) (*gomemcached.MCResponse, error) {
+	res, err := c.AuthList()
+	if err != nil {
+		return nil, errors.Wrap(err, "Unable to obtain list of methods.")
+	}
+
+	methods := string(res.Body)
+	method, err := scramsha.BestMethod(methods)
+	if err != nil {
+		return nil, errors.Wrap(err,
+			"Unable to select SCRAM-SHA method.")
+	}
+
+	s, err := scramsha.NewScramSha(method)
+	if err != nil {
+		return nil, errors.Wrap(err, "Unable to initialize scramsha.")
+	}
+
+	logging.Infof("Using %v authentication for user %v%v%v", method, gomemcached.UdTagBegin, user, gomemcached.UdTagEnd)
+
+	message, err := s.GetStartRequest(user)
+	if err != nil {
+		return nil, errors.Wrapf(err,
+			"Error building start request for user %s.", user)
+	}
+
+	startRequest := &gomemcached.MCRequest{
+		Opcode: 0x21,
+		Key:    []byte(method),
+		Body:   []byte(message)}
+
+	startResponse, err := c.Send(startRequest)
+	if err != nil {
+		return nil, errors.Wrap(err, "Error sending start request.")
+	}
+
+	err = s.HandleStartResponse(string(startResponse.Body))
+	if err != nil {
+		return nil, errors.Wrap(err, "Error handling start response.")
+	}
+
+	message = s.GetFinalRequest(pass)
+
+	// send step request
+	finalRequest := &gomemcached.MCRequest{
+		Opcode: 0x22,
+		Key:    []byte(method),
+		Body:   []byte(message)}
+	finalResponse, err := c.Send(finalRequest)
+	if err != nil {
+		return nil, errors.Wrap(err, "Error sending final request.")
+	}
+
+	err = s.HandleFinalResponse(string(finalResponse.Body))
+	if err != nil {
+		return nil, errors.Wrap(err, "Error handling final response.")
+	}
+
+	return finalResponse, nil
+}
+
+func (c *Client) AuthPlain(user, pass string) (*gomemcached.MCResponse, error) {
+	logging.Infof("Using plain authentication for user %v%v%v", gomemcached.UdTagBegin, user, gomemcached.UdTagEnd)
+	return c.Send(&gomemcached.MCRequest{
+		Opcode: gomemcached.SASL_AUTH,
+		Key:    []byte("PLAIN"),
+		Body:   []byte(fmt.Sprintf("\x00%s\x00%s", user, pass))})
+}
+
+// select bucket
+func (c *Client) SelectBucket(bucket string) (*gomemcached.MCResponse, error) {
+
+	return c.Send(&gomemcached.MCRequest{
+		Opcode: gomemcached.SELECT_BUCKET,
+		Key:    []byte(fmt.Sprintf("%s", bucket))})
+}
+
+func (c *Client) store(opcode gomemcached.CommandCode, vb uint16,
+	key string, flags int, exp int, body []byte) (*gomemcached.MCResponse, error) {
+
+	req := &gomemcached.MCRequest{
+		Opcode:  opcode,
+		VBucket: vb,
+		Key:     []byte(key),
+		Cas:     0,
+		Opaque:  0,
+		Extras:  []byte{0, 0, 0, 0, 0, 0, 0, 0},
+		Body:    body}
+
+	binary.BigEndian.PutUint64(req.Extras, uint64(flags)<<32|uint64(exp))
+	return c.Send(req)
+}
+
+func (c *Client) storeCas(opcode gomemcached.CommandCode, vb uint16,
+	key string, flags int, exp int, cas uint64, body []byte) (*gomemcached.MCResponse, error) {
+
+	req := &gomemcached.MCRequest{
+		Opcode:  opcode,
+		VBucket: vb,
+		Key:     []byte(key),
+		Cas:     cas,
+		Opaque:  0,
+		Extras:  []byte{0, 0, 0, 0, 0, 0, 0, 0},
+		Body:    body}
+
+	binary.BigEndian.PutUint64(req.Extras, uint64(flags)<<32|uint64(exp))
+	return c.Send(req)
+}
+
+// Incr increments the value at the given key.
+func (c *Client) Incr(vb uint16, key string,
+	amt, def uint64, exp int) (uint64, error) {
+
+	req := &gomemcached.MCRequest{
+		Opcode:  gomemcached.INCREMENT,
+		VBucket: vb,
+		Key:     []byte(key),
+		Extras:  make([]byte, 8+8+4),
+	}
+	binary.BigEndian.PutUint64(req.Extras[:8], amt)
+	binary.BigEndian.PutUint64(req.Extras[8:16], def)
+	binary.BigEndian.PutUint32(req.Extras[16:20], uint32(exp))
+
+	resp, err := c.Send(req)
+	if err != nil {
+		return 0, err
+	}
+
+	return binary.BigEndian.Uint64(resp.Body), nil
+}
+
+// Decr decrements the value at the given key.
+func (c *Client) Decr(vb uint16, key string,
+	amt, def uint64, exp int) (uint64, error) {
+
+	req := &gomemcached.MCRequest{
+		Opcode:  gomemcached.DECREMENT,
+		VBucket: vb,
+		Key:     []byte(key),
+		Extras:  make([]byte, 8+8+4),
+	}
+	binary.BigEndian.PutUint64(req.Extras[:8], amt)
+	binary.BigEndian.PutUint64(req.Extras[8:16], def)
+	binary.BigEndian.PutUint32(req.Extras[16:20], uint32(exp))
+
+	resp, err := c.Send(req)
+	if err != nil {
+		return 0, err
+	}
+
+	return binary.BigEndian.Uint64(resp.Body), nil
+}
+
+// Add a value for a key (store if not exists).
+func (c *Client) Add(vb uint16, key string, flags int, exp int,
+	body []byte) (*gomemcached.MCResponse, error) {
+	return c.store(gomemcached.ADD, vb, key, flags, exp, body)
+}
+
+// Set the value for a key.
+func (c *Client) Set(vb uint16, key string, flags int, exp int,
+	body []byte) (*gomemcached.MCResponse, error) {
+	return c.store(gomemcached.SET, vb, key, flags, exp, body)
+}
+
+// SetCas set the value for a key with cas
+func (c *Client) SetCas(vb uint16, key string, flags int, exp int, cas uint64,
+	body []byte) (*gomemcached.MCResponse, error) {
+	return c.storeCas(gomemcached.SET, vb, key, flags, exp, cas, body)
+}
+
+// Append data to the value of a key.
+func (c *Client) Append(vb uint16, key string, data []byte) (*gomemcached.MCResponse, error) {
+	req := &gomemcached.MCRequest{
+		Opcode:  gomemcached.APPEND,
+		VBucket: vb,
+		Key:     []byte(key),
+		Cas:     0,
+		Opaque:  0,
+		Body:    data}
+
+	return c.Send(req)
+}
+
+// GetBulk gets keys in bulk
+func (c *Client) GetBulk(vb uint16, keys []string, rv map[string]*gomemcached.MCResponse, subPaths []string) error {
+	stopch := make(chan bool)
+	var wg sync.WaitGroup
+
+	defer func() {
+		close(stopch)
+		wg.Wait()
+	}()
+
+	if (math.MaxInt32 - c.opaque) < (uint32(len(keys)) + 1) {
+		c.opaque = uint32(1)
+	}
+
+	opStart := c.opaque
+
+	errch := make(chan error, 2)
+
+	wg.Add(1)
+	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				logging.Infof("Recovered in f %v", r)
+			}
+			errch <- nil
+			wg.Done()
+		}()
+
+		ok := true
+		for ok {
+
+			select {
+			case <-stopch:
+				return
+			default:
+				res, err := c.Receive()
+
+				if err != nil && IfResStatusError(res) {
+					if res == nil || res.Status != gomemcached.KEY_ENOENT {
+						errch <- err
+						return
+					}
+					// continue receiving in case of KEY_ENOENT
+				} else if res.Opcode == gomemcached.GET ||
+					res.Opcode == gomemcached.SUBDOC_GET ||
+					res.Opcode == gomemcached.SUBDOC_MULTI_LOOKUP {
+					opaque := res.Opaque - opStart
+					if opaque < 0 || opaque >= uint32(len(keys)) {
+						// Every now and then we seem to be seeing an invalid opaque
+						// value returned from the server. When this happens log the error
+						// and the calling function will retry the bulkGet. MB-15140
+						logging.Errorf(" Invalid opaque Value. Debug info : Res.opaque : %v(%v), Keys %v, Response received %v \n key list %v this key %v", res.Opaque, opaque, len(keys), res, keys, string(res.Body))
+						errch <- fmt.Errorf("Out of Bounds error")
+						return
+					}
+
+					rv[keys[opaque]] = res
+				}
+
+				if res.Opcode == gomemcached.NOOP {
+					ok = false
+				}
+			}
+		}
+	}()
+
+	memcachedReqPkt := &gomemcached.MCRequest{
+		Opcode:  gomemcached.GET,
+		VBucket: vb,
+	}
+
+	if len(subPaths) > 0 {
+		extraBuf, valueBuf := GetSubDocVal(subPaths)
+		memcachedReqPkt.Opcode = gomemcached.SUBDOC_MULTI_LOOKUP
+		memcachedReqPkt.Extras = extraBuf
+		memcachedReqPkt.Body = valueBuf
+	}
+
+	for _, k := range keys { // Start of Get request
+		memcachedReqPkt.Key = []byte(k)
+		memcachedReqPkt.Opaque = c.opaque
+
+		err := c.Transmit(memcachedReqPkt)
+		if err != nil {
+			logging.Errorf(" Transmit failed in GetBulkAll %v", err)
+			return err
+		}
+		c.opaque++
+	} // End of Get request
+
+	// finally transmit a NOOP
+	err := c.Transmit(&gomemcached.MCRequest{
+		Opcode:  gomemcached.NOOP,
+		VBucket: vb,
+		Opaque:  c.opaque,
+	})
+
+	if err != nil {
+		logging.Errorf(" Transmit of NOOP failed  %v", err)
+		return err
+	}
+	c.opaque++
+
+	return <-errch
+}
+
+func GetSubDocVal(subPaths []string) (extraBuf, valueBuf []byte) {
+
+	var ops []string
+	totalBytesLen := 0
+	num := 1
+
+	for _, v := range subPaths {
+		totalBytesLen = totalBytesLen + len([]byte(v))
+		ops = append(ops, v)
+		num = num + 1
+	}
+
+	// Xattr retrieval - subdoc multi get
+	extraBuf = append(extraBuf, uint8(0x04))
+
+	valueBuf = make([]byte, num*4+totalBytesLen)
+
+	//opcode for subdoc get
+	op := gomemcached.SUBDOC_GET
+
+	// Calculate path total bytes
+	// There are 2 ops - get xattrs - both input and $document and get whole doc
+	valIter := 0
+
+	for _, v := range ops {
+		pathBytes := []byte(v)
+		valueBuf[valIter+0] = uint8(op)
+
+		// SubdocFlagXattrPath indicates that the path refers to
+		// an Xattr rather than the document body.
+		valueBuf[valIter+1] = uint8(gomemcached.SUBDOC_FLAG_XATTR)
+
+		// 2 byte key
+		binary.BigEndian.PutUint16(valueBuf[valIter+2:], uint16(len(pathBytes)))
+
+		// Then n bytes path
+		copy(valueBuf[valIter+4:], pathBytes)
+		valIter = valIter + 4 + len(pathBytes)
+	}
+
+	return
+}
+
+// ObservedStatus is the type reported by the Observe method
+type ObservedStatus uint8
+
+// Observation status values.
+const (
+	ObservedNotPersisted     = ObservedStatus(0x00) // found, not persisted
+	ObservedPersisted        = ObservedStatus(0x01) // found, persisted
+	ObservedNotFound         = ObservedStatus(0x80) // not found (or a persisted delete)
+	ObservedLogicallyDeleted = ObservedStatus(0x81) // pending deletion (not persisted yet)
+)
+
+// ObserveResult represents the data obtained by an Observe call
+type ObserveResult struct {
+	Status          ObservedStatus // Whether the value has been persisted/deleted
+	Cas             uint64         // Current value's CAS
+	PersistenceTime time.Duration  // Node's average time to persist a value
+	ReplicationTime time.Duration  // Node's average time to replicate a value
+}
+
+// Observe gets the persistence/replication/CAS state of a key
+func (c *Client) Observe(vb uint16, key string) (result ObserveResult, err error) {
+	// http://www.couchbase.com/wiki/display/couchbase/Observe
+	body := make([]byte, 4+len(key))
+	binary.BigEndian.PutUint16(body[0:2], vb)
+	binary.BigEndian.PutUint16(body[2:4], uint16(len(key)))
+	copy(body[4:4+len(key)], key)
+
+	res, err := c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.OBSERVE,
+		VBucket: vb,
+		Body:    body,
+	})
+	if err != nil {
+		return
+	}
+
+	// Parse the response data from the body:
+	if len(res.Body) < 2+2+1 {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+	outVb := binary.BigEndian.Uint16(res.Body[0:2])
+	keyLen := binary.BigEndian.Uint16(res.Body[2:4])
+	if len(res.Body) < 2+2+int(keyLen)+1+8 {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+	outKey := string(res.Body[4 : 4+keyLen])
+	if outVb != vb || outKey != key {
+		err = fmt.Errorf("observe returned wrong vbucket/key: %d/%q", outVb, outKey)
+		return
+	}
+	result.Status = ObservedStatus(res.Body[4+keyLen])
+	result.Cas = binary.BigEndian.Uint64(res.Body[5+keyLen:])
+	// The response reuses the Cas field to store time statistics:
+	result.PersistenceTime = time.Duration(res.Cas>>32) * time.Millisecond
+	result.ReplicationTime = time.Duration(res.Cas&math.MaxUint32) * time.Millisecond
+	return
+}
+
+// CheckPersistence checks whether a stored value has been persisted to disk yet.
+func (result ObserveResult) CheckPersistence(cas uint64, deletion bool) (persisted bool, overwritten bool) {
+	switch {
+	case result.Status == ObservedNotFound && deletion:
+		persisted = true
+	case result.Cas != cas:
+		overwritten = true
+	case result.Status == ObservedPersisted:
+		persisted = true
+	}
+	return
+}
+
+// Sequence number based Observe Implementation
+type ObserveSeqResult struct {
+	Failover           uint8  // Set to 1 if a failover took place
+	VbId               uint16 // vbucket id
+	Vbuuid             uint64 // vucket uuid
+	LastPersistedSeqNo uint64 // last persisted sequence number
+	CurrentSeqNo       uint64 // current sequence number
+	OldVbuuid          uint64 // Old bucket vbuuid
+	LastSeqNo          uint64 // last sequence number received before failover
+}
+
+func (c *Client) ObserveSeq(vb uint16, vbuuid uint64) (result *ObserveSeqResult, err error) {
+	// http://www.couchbase.com/wiki/display/couchbase/Observe
+	body := make([]byte, 8)
+	binary.BigEndian.PutUint64(body[0:8], vbuuid)
+
+	res, err := c.Send(&gomemcached.MCRequest{
+		Opcode:  gomemcached.OBSERVE_SEQNO,
+		VBucket: vb,
+		Body:    body,
+		Opaque:  0x01,
+	})
+	if err != nil {
+		return
+	}
+
+	if res.Status != gomemcached.SUCCESS {
+		return nil, fmt.Errorf(" Observe returned error %v", res.Status)
+	}
+
+	// Parse the response data from the body:
+	if len(res.Body) < (1 + 2 + 8 + 8 + 8) {
+		err = io.ErrUnexpectedEOF
+		return
+	}
+
+	result = &ObserveSeqResult{}
+	result.Failover = res.Body[0]
+	result.VbId = binary.BigEndian.Uint16(res.Body[1:3])
+	result.Vbuuid = binary.BigEndian.Uint64(res.Body[3:11])
+	result.LastPersistedSeqNo = binary.BigEndian.Uint64(res.Body[11:19])
+	result.CurrentSeqNo = binary.BigEndian.Uint64(res.Body[19:27])
+
+	// in case of failover processing we can have old vbuuid and the last persisted seq number
+	if result.Failover == 1 && len(res.Body) >= (1+2+8+8+8+8+8) {
+		result.OldVbuuid = binary.BigEndian.Uint64(res.Body[27:35])
+		result.LastSeqNo = binary.BigEndian.Uint64(res.Body[35:43])
+	}
+
+	return
+}
+
+// CasOp is the type of operation to perform on this CAS loop.
+type CasOp uint8
+
+const (
+	// CASStore instructs the server to store the new value normally
+	CASStore = CasOp(iota)
+	// CASQuit instructs the client to stop attempting to CAS, leaving value untouched
+	CASQuit
+	// CASDelete instructs the server to delete the current value
+	CASDelete
+)
+
+// User specified termination is returned as an error.
+func (c CasOp) Error() string {
+	switch c {
+	case CASStore:
+		return "CAS store"
+	case CASQuit:
+		return "CAS quit"
+	case CASDelete:
+		return "CAS delete"
+	}
+	panic("Unhandled value")
+}
+
+//////// CAS TRANSFORM
+
+// CASState tracks the state of CAS over several operations.
+//
+// This is used directly by CASNext and indirectly by CAS
+type CASState struct {
+	initialized bool   // false on the first call to CASNext, then true
+	Value       []byte // Current value of key; update in place to new value
+	Cas         uint64 // Current CAS value of key
+	Exists      bool   // Does a value exist for the key? (If not, Value will be nil)
+	Err         error  // Error, if any, after CASNext returns false
+	resp        *gomemcached.MCResponse
+}
+
+// CASNext is a non-callback, loop-based version of CAS method.
+//
+//  Usage is like this:
+//
+// var state memcached.CASState
+// for client.CASNext(vb, key, exp, &state) {
+//     state.Value = some_mutation(state.Value)
+// }
+// if state.Err != nil { ... }
+func (c *Client) CASNext(vb uint16, k string, exp int, state *CASState) bool {
+	if state.initialized {
+		if !state.Exists {
+			// Adding a new key:
+			if state.Value == nil {
+				state.Cas = 0
+				return false // no-op (delete of non-existent value)
+			}
+			state.resp, state.Err = c.Add(vb, k, 0, exp, state.Value)
+		} else {
+			// Updating / deleting a key:
+			req := &gomemcached.MCRequest{
+				Opcode:  gomemcached.DELETE,
+				VBucket: vb,
+				Key:     []byte(k),
+				Cas:     state.Cas}
+			if state.Value != nil {
+				req.Opcode = gomemcached.SET
+				req.Opaque = 0
+				req.Extras = []byte{0, 0, 0, 0, 0, 0, 0, 0}
+				req.Body = state.Value
+
+				flags := 0
+				binary.BigEndian.PutUint64(req.Extras, uint64(flags)<<32|uint64(exp))
+			}
+			state.resp, state.Err = c.Send(req)
+		}
+
+		// If the response status is KEY_EEXISTS or NOT_STORED there's a conflict and we'll need to
+		// get the new value (below). Otherwise, we're done (either success or failure) so return:
+		if !(state.resp != nil && (state.resp.Status == gomemcached.KEY_EEXISTS ||
+			state.resp.Status == gomemcached.NOT_STORED)) {
+			state.Cas = state.resp.Cas
+			return false // either success or fatal error
+		}
+	}
+
+	// Initial call, or after a conflict: GET the current value and CAS and return them:
+	state.initialized = true
+	if state.resp, state.Err = c.Get(vb, k); state.Err == nil {
+		state.Exists = true
+		state.Value = state.resp.Body
+		state.Cas = state.resp.Cas
+	} else if state.resp != nil && state.resp.Status == gomemcached.KEY_ENOENT {
+		state.Err = nil
+		state.Exists = false
+		state.Value = nil
+		state.Cas = 0
+	} else {
+		return false // fatal error
+	}
+	return true // keep going...
+}
+
+// CasFunc is type type of function to perform a CAS transform.
+//
+// Input is the current value, or nil if no value exists.
+// The function should return the new value (if any) to set, and the store/quit/delete operation.
+type CasFunc func(current []byte) ([]byte, CasOp)
+
+// CAS performs a CAS transform with the given function.
+//
+// If the value does not exist, a nil current value will be sent to f.
+func (c *Client) CAS(vb uint16, k string, f CasFunc,
+	initexp int) (*gomemcached.MCResponse, error) {
+	var state CASState
+	for c.CASNext(vb, k, initexp, &state) {
+		newValue, operation := f(state.Value)
+		if operation == CASQuit || (operation == CASDelete && state.Value == nil) {
+			return nil, operation
+		}
+		state.Value = newValue
+	}
+	return state.resp, state.Err
+}
+
+// StatValue is one of the stats returned from the Stats method.
+type StatValue struct {
+	// The stat key
+	Key string
+	// The stat value
+	Val string
+}
+
+// Stats requests server-side stats.
+//
+// Use "" as the stat key for toplevel stats.
+func (c *Client) Stats(key string) ([]StatValue, error) {
+	rv := make([]StatValue, 0, 128)
+
+	req := &gomemcached.MCRequest{
+		Opcode: gomemcached.STAT,
+		Key:    []byte(key),
+		Opaque: 918494,
+	}
+
+	err := c.Transmit(req)
+	if err != nil {
+		return rv, err
+	}
+
+	for {
+		res, _, err := getResponse(c.conn, c.hdrBuf)
+		if err != nil {
+			return rv, err
+		}
+		k := string(res.Key)
+		if k == "" {
+			break
+		}
+		rv = append(rv, StatValue{
+			Key: k,
+			Val: string(res.Body),
+		})
+	}
+	return rv, nil
+}
+
+// StatsMap requests server-side stats similarly to Stats, but returns
+// them as a map.
+//
+// Use "" as the stat key for toplevel stats.
+func (c *Client) StatsMap(key string) (map[string]string, error) {
+	rv := make(map[string]string)
+
+	req := &gomemcached.MCRequest{
+		Opcode: gomemcached.STAT,
+		Key:    []byte(key),
+		Opaque: 918494,
+	}
+
+	err := c.Transmit(req)
+	if err != nil {
+		return rv, err
+	}
+
+	for {
+		res, _, err := getResponse(c.conn, c.hdrBuf)
+		if err != nil {
+			return rv, err
+		}
+		k := string(res.Key)
+		if k == "" {
+			break
+		}
+		rv[k] = string(res.Body)
+	}
+
+	return rv, nil
+}
+
+// instead of returning a new statsMap, simply populate passed in statsMap, which contains all the keys
+// for which stats needs to be retrieved
+func (c *Client) StatsMapForSpecifiedStats(key string, statsMap map[string]string) error {
+
+	// clear statsMap
+	for key, _ := range statsMap {
+		statsMap[key] = ""
+	}
+
+	req := &gomemcached.MCRequest{
+		Opcode: gomemcached.STAT,
+		Key:    []byte(key),
+		Opaque: 918494,
+	}
+
+	err := c.Transmit(req)
+	if err != nil {
+		return err
+	}
+
+	for {
+		res, _, err := getResponse(c.conn, c.hdrBuf)
+		if err != nil {
+			return err
+		}
+		k := string(res.Key)
+		if k == "" {
+			break
+		}
+		if _, ok := statsMap[k]; ok {
+			statsMap[k] = string(res.Body)
+		}
+	}
+
+	return nil
+}
+
+// Hijack exposes the underlying connection from this client.
+//
+// It also marks the connection as unhealthy since the client will
+// have lost control over the connection and can't otherwise verify
+// things are in good shape for connection pools.
+func (c *Client) Hijack() io.ReadWriteCloser {
+	c.setHealthy(false)
+	return c.conn
+}
+
+func (c *Client) setHealthy(healthy bool) {
+	healthyState := UnHealthy
+	if healthy {
+		healthyState = Healthy
+	}
+	atomic.StoreUint32(&c.healthy, healthyState)
+}
+
+func IfResStatusError(response *gomemcached.MCResponse) bool {
+	return response == nil ||
+		(response.Status != gomemcached.SUBDOC_BAD_MULTI &&
+			response.Status != gomemcached.SUBDOC_PATH_NOT_FOUND &&
+			response.Status != gomemcached.SUBDOC_MULTI_PATH_FAILURE_DELETED)
+}
diff --git a/vendor/github.com/couchbase/gomemcached/client/tap_feed.go b/vendor/github.com/couchbase/gomemcached/client/tap_feed.go
new file mode 100644
index 0000000000..fd628c5de2
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/client/tap_feed.go
@@ -0,0 +1,333 @@
+package memcached
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"math"
+
+	"github.com/couchbase/gomemcached"
+	"github.com/couchbase/goutils/logging"
+)
+
+// TAP protocol docs: <http://www.couchbase.com/wiki/display/couchbase/TAP+Protocol>
+
+// TapOpcode is the tap operation type (found in TapEvent)
+type TapOpcode uint8
+
+// Tap opcode values.
+const (
+	TapBeginBackfill = TapOpcode(iota)
+	TapEndBackfill
+	TapMutation
+	TapDeletion
+	TapCheckpointStart
+	TapCheckpointEnd
+	tapEndStream
+)
+
+const tapMutationExtraLen = 16
+
+var tapOpcodeNames map[TapOpcode]string
+
+func init() {
+	tapOpcodeNames = map[TapOpcode]string{
+		TapBeginBackfill:   "BeginBackfill",
+		TapEndBackfill:     "EndBackfill",
+		TapMutation:        "Mutation",
+		TapDeletion:        "Deletion",
+		TapCheckpointStart: "TapCheckpointStart",
+		TapCheckpointEnd:   "TapCheckpointEnd",
+		tapEndStream:       "EndStream",
+	}
+}
+
+func (opcode TapOpcode) String() string {
+	name := tapOpcodeNames[opcode]
+	if name == "" {
+		name = fmt.Sprintf("#%d", opcode)
+	}
+	return name
+}
+
+// TapEvent is a TAP notification of an operation on the server.
+type TapEvent struct {
+	Opcode     TapOpcode // Type of event
+	VBucket    uint16    // VBucket this event applies to
+	Flags      uint32    // Item flags
+	Expiry     uint32    // Item expiration time
+	Key, Value []byte    // Item key/value
+	Cas        uint64
+}
+
+func makeTapEvent(req gomemcached.MCRequest) *TapEvent {
+	event := TapEvent{
+		VBucket: req.VBucket,
+	}
+	switch req.Opcode {
+	case gomemcached.TAP_MUTATION:
+		event.Opcode = TapMutation
+		event.Key = req.Key
+		event.Value = req.Body
+		event.Cas = req.Cas
+	case gomemcached.TAP_DELETE:
+		event.Opcode = TapDeletion
+		event.Key = req.Key
+		event.Cas = req.Cas
+	case gomemcached.TAP_CHECKPOINT_START:
+		event.Opcode = TapCheckpointStart
+	case gomemcached.TAP_CHECKPOINT_END:
+		event.Opcode = TapCheckpointEnd
+	case gomemcached.TAP_OPAQUE:
+		if len(req.Extras) < 8+4 {
+			return nil
+		}
+		switch op := int(binary.BigEndian.Uint32(req.Extras[8:])); op {
+		case gomemcached.TAP_OPAQUE_INITIAL_VBUCKET_STREAM:
+			event.Opcode = TapBeginBackfill
+		case gomemcached.TAP_OPAQUE_CLOSE_BACKFILL:
+			event.Opcode = TapEndBackfill
+		case gomemcached.TAP_OPAQUE_CLOSE_TAP_STREAM:
+			event.Opcode = tapEndStream
+		case gomemcached.TAP_OPAQUE_ENABLE_AUTO_NACK:
+			return nil
+		case gomemcached.TAP_OPAQUE_ENABLE_CHECKPOINT_SYNC:
+			return nil
+		default:
+			logging.Infof("TapFeed: Ignoring TAP_OPAQUE/%d", op)
+			return nil // unknown opaque event
+		}
+	case gomemcached.NOOP:
+		return nil // ignore
+	default:
+		logging.Infof("TapFeed: Ignoring %s", req.Opcode)
+		return nil // unknown event
+	}
+
+	if len(req.Extras) >= tapMutationExtraLen &&
+		(event.Opcode == TapMutation || event.Opcode == TapDeletion) {
+
+		event.Flags = binary.BigEndian.Uint32(req.Extras[8:])
+		event.Expiry = binary.BigEndian.Uint32(req.Extras[12:])
+	}
+
+	return &event
+}
+
+func (event TapEvent) String() string {
+	switch event.Opcode {
+	case TapBeginBackfill, TapEndBackfill, TapCheckpointStart, TapCheckpointEnd:
+		return fmt.Sprintf("<TapEvent %s, vbucket=%d>",
+			event.Opcode, event.VBucket)
+	default:
+		return fmt.Sprintf("<TapEvent %s, key=%q (%d bytes) flags=%x, exp=%d>",
+			event.Opcode, event.Key, len(event.Value),
+			event.Flags, event.Expiry)
+	}
+}
+
+// TapArguments are parameters for requesting a TAP feed.
+//
+// Call DefaultTapArguments to get a default one.
+type TapArguments struct {
+	// Timestamp of oldest item to send.
+	//
+	// Use TapNoBackfill to suppress all past items.
+	Backfill uint64
+	// If set, server will disconnect after sending existing items.
+	Dump bool
+	// The indices of the vbuckets to watch; empty/nil to watch all.
+	VBuckets []uint16
+	// Transfers ownership of vbuckets during cluster rebalance.
+	Takeover bool
+	// If true, server will wait for client ACK after every notification.
+	SupportAck bool
+	// If true, client doesn't want values so server shouldn't send them.
+	KeysOnly bool
+	// If true, client wants the server to send checkpoint events.
+	Checkpoint bool
+	// Optional identifier to use for this client, to allow reconnects
+	ClientName string
+	// Registers this client (by name) till explicitly deregistered.
+	RegisteredClient bool
+}
+
+// Value for TapArguments.Backfill denoting that no past events at all
+// should be sent.
+const TapNoBackfill = math.MaxUint64
+
+// DefaultTapArguments returns a default set of parameter values to
+// pass to StartTapFeed.
+func DefaultTapArguments() TapArguments {
+	return TapArguments{
+		Backfill: TapNoBackfill,
+	}
+}
+
+func (args *TapArguments) flags() []byte {
+	var flags gomemcached.TapConnectFlag
+	if args.Backfill != 0 {
+		flags |= gomemcached.BACKFILL
+	}
+	if args.Dump {
+		flags |= gomemcached.DUMP
+	}
+	if len(args.VBuckets) > 0 {
+		flags |= gomemcached.LIST_VBUCKETS
+	}
+	if args.Takeover {
+		flags |= gomemcached.TAKEOVER_VBUCKETS
+	}
+	if args.SupportAck {
+		flags |= gomemcached.SUPPORT_ACK
+	}
+	if args.KeysOnly {
+		flags |= gomemcached.REQUEST_KEYS_ONLY
+	}
+	if args.Checkpoint {
+		flags |= gomemcached.CHECKPOINT
+	}
+	if args.RegisteredClient {
+		flags |= gomemcached.REGISTERED_CLIENT
+	}
+	encoded := make([]byte, 4)
+	binary.BigEndian.PutUint32(encoded, uint32(flags))
+	return encoded
+}
+
+func must(err error) {
+	if err != nil {
+		panic(err)
+	}
+}
+
+func (args *TapArguments) bytes() (rv []byte) {
+	buf := bytes.NewBuffer([]byte{})
+
+	if args.Backfill > 0 {
+		must(binary.Write(buf, binary.BigEndian, uint64(args.Backfill)))
+	}
+
+	if len(args.VBuckets) > 0 {
+		must(binary.Write(buf, binary.BigEndian, uint16(len(args.VBuckets))))
+		for i := 0; i < len(args.VBuckets); i++ {
+			must(binary.Write(buf, binary.BigEndian, uint16(args.VBuckets[i])))
+		}
+	}
+	return buf.Bytes()
+}
+
+// TapFeed represents a stream of events from a server.
+type TapFeed struct {
+	C      <-chan TapEvent
+	Error  error
+	closer chan bool
+}
+
+// StartTapFeed starts a TAP feed on a client connection.
+//
+// The events can be read from the returned channel.  The connection
+// can no longer be used for other purposes; it's now reserved for
+// receiving the TAP messages. To stop receiving events, close the
+// client connection.
+func (mc *Client) StartTapFeed(args TapArguments) (*TapFeed, error) {
+	rq := &gomemcached.MCRequest{
+		Opcode: gomemcached.TAP_CONNECT,
+		Key:    []byte(args.ClientName),
+		Extras: args.flags(),
+		Body:   args.bytes()}
+
+	err := mc.Transmit(rq)
+	if err != nil {
+		return nil, err
+	}
+
+	ch := make(chan TapEvent)
+	feed := &TapFeed{
+		C:      ch,
+		closer: make(chan bool),
+	}
+	go mc.runFeed(ch, feed)
+	return feed, nil
+}
+
+// TapRecvHook is called after every incoming tap packet is received.
+var TapRecvHook func(*gomemcached.MCRequest, int, error)
+
+// Internal goroutine that reads from the socket and writes events to
+// the channel
+func (mc *Client) runFeed(ch chan TapEvent, feed *TapFeed) {
+	defer close(ch)
+	var headerBuf [gomemcached.HDR_LEN]byte
+loop:
+	for {
+		// Read the next request from the server.
+		//
+		//  (Can't call mc.Receive() because it reads a
+		//  _response_ not a request.)
+		var pkt gomemcached.MCRequest
+		n, err := pkt.Receive(mc.conn, headerBuf[:])
+		if TapRecvHook != nil {
+			TapRecvHook(&pkt, n, err)
+		}
+
+		if err != nil {
+			if err != io.EOF {
+				feed.Error = err
+			}
+			break loop
+		}
+
+		//logging.Infof("** TapFeed received %#v : %q", pkt, pkt.Body)
+
+		if pkt.Opcode == gomemcached.TAP_CONNECT {
+			// This is not an event from the server; it's
+			// an error response to my connect request.
+			feed.Error = fmt.Errorf("tap connection failed: %s", pkt.Body)
+			break loop
+		}
+
+		event := makeTapEvent(pkt)
+		if event != nil {
+			if event.Opcode == tapEndStream {
+				break loop
+			}
+
+			select {
+			case ch <- *event:
+			case <-feed.closer:
+				break loop
+			}
+		}
+
+		if len(pkt.Extras) >= 4 {
+			reqFlags := binary.BigEndian.Uint16(pkt.Extras[2:])
+			if reqFlags&gomemcached.TAP_ACK != 0 {
+				if _, err := mc.sendAck(&pkt); err != nil {
+					feed.Error = err
+					break loop
+				}
+			}
+		}
+	}
+	if err := mc.Close(); err != nil {
+		logging.Errorf("Error closing memcached client:  %v", err)
+	}
+}
+
+func (mc *Client) sendAck(pkt *gomemcached.MCRequest) (int, error) {
+	res := gomemcached.MCResponse{
+		Opcode: pkt.Opcode,
+		Opaque: pkt.Opaque,
+		Status: gomemcached.SUCCESS,
+	}
+	return res.Transmit(mc.conn)
+}
+
+// Close terminates a TapFeed.
+//
+//  Call this if you stop using a TapFeed before its channel ends.
+func (feed *TapFeed) Close() {
+	close(feed.closer)
+}
diff --git a/vendor/github.com/couchbase/gomemcached/client/transport.go b/vendor/github.com/couchbase/gomemcached/client/transport.go
new file mode 100644
index 0000000000..f4cea17fca
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/client/transport.go
@@ -0,0 +1,67 @@
+package memcached
+
+import (
+	"errors"
+	"io"
+
+	"github.com/couchbase/gomemcached"
+)
+
+var errNoConn = errors.New("no connection")
+
+// UnwrapMemcachedError converts memcached errors to normal responses.
+//
+// If the error is a memcached response, declare the error to be nil
+// so a client can handle the status without worrying about whether it
+// indicates success or failure.
+func UnwrapMemcachedError(rv *gomemcached.MCResponse,
+	err error) (*gomemcached.MCResponse, error) {
+
+	if rv == err {
+		return rv, nil
+	}
+	return rv, err
+}
+
+// ReceiveHook is called after every packet is received (or attempted to be)
+var ReceiveHook func(*gomemcached.MCResponse, int, error)
+
+func getResponse(s io.Reader, hdrBytes []byte) (rv *gomemcached.MCResponse, n int, err error) {
+	if s == nil {
+		return nil, 0, errNoConn
+	}
+
+	rv = &gomemcached.MCResponse{}
+	n, err = rv.Receive(s, hdrBytes)
+
+	if ReceiveHook != nil {
+		ReceiveHook(rv, n, err)
+	}
+
+	if err == nil && (rv.Status != gomemcached.SUCCESS && rv.Status != gomemcached.AUTH_CONTINUE) {
+		err = rv
+	}
+	return rv, n, err
+}
+
+// TransmitHook is called after each packet is transmitted.
+var TransmitHook func(*gomemcached.MCRequest, int, error)
+
+func transmitRequest(o io.Writer, req *gomemcached.MCRequest) (int, error) {
+	if o == nil {
+		return 0, errNoConn
+	}
+	n, err := req.Transmit(o)
+	if TransmitHook != nil {
+		TransmitHook(req, n, err)
+	}
+	return n, err
+}
+
+func transmitResponse(o io.Writer, res *gomemcached.MCResponse) (int, error) {
+	if o == nil {
+		return 0, errNoConn
+	}
+	n, err := res.Transmit(o)
+	return n, err
+}
diff --git a/vendor/github.com/couchbase/gomemcached/client/upr_feed.go b/vendor/github.com/couchbase/gomemcached/client/upr_feed.go
new file mode 100644
index 0000000000..dc737e6cc0
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/client/upr_feed.go
@@ -0,0 +1,1005 @@
+// go implementation of upr client.
+// See https://github.com/couchbaselabs/cbupr/blob/master/transport-spec.md
+// TODO
+// 1. Use a pool allocator to avoid garbage
+package memcached
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"github.com/couchbase/gomemcached"
+	"github.com/couchbase/goutils/logging"
+	"strconv"
+	"sync"
+	"sync/atomic"
+)
+
+const uprMutationExtraLen = 30
+const uprDeletetionExtraLen = 18
+const uprDeletetionWithDeletionTimeExtraLen = 21
+const uprSnapshotExtraLen = 20
+const bufferAckThreshold = 0.2
+const opaqueOpen = 0xBEAF0001
+const opaqueFailover = 0xDEADBEEF
+const uprDefaultNoopInterval = 120
+
+// Counter on top of opaqueOpen that others can draw from for open and control msgs
+var opaqueOpenCtrlWell uint32 = opaqueOpen
+
+// UprEvent memcached events for UPR streams.
+type UprEvent struct {
+	Opcode       gomemcached.CommandCode // Type of event
+	Status       gomemcached.Status      // Response status
+	VBucket      uint16                  // VBucket this event applies to
+	DataType     uint8                   // data type
+	Opaque       uint16                  // 16 MSB of opaque
+	VBuuid       uint64                  // This field is set by downstream
+	Flags        uint32                  // Item flags
+	Expiry       uint32                  // Item expiration time
+	Key, Value   []byte                  // Item key/value
+	OldValue     []byte                  // TODO: TBD: old document value
+	Cas          uint64                  // CAS value of the item
+	Seqno        uint64                  // sequence number of the mutation
+	RevSeqno     uint64                  // rev sequence number : deletions
+	LockTime     uint32                  // Lock time
+	MetadataSize uint16                  // Metadata size
+	SnapstartSeq uint64                  // start sequence number of this snapshot
+	SnapendSeq   uint64                  // End sequence number of the snapshot
+	SnapshotType uint32                  // 0: disk 1: memory
+	FailoverLog  *FailoverLog            // Failover log containing vvuid and sequnce number
+	Error        error                   // Error value in case of a failure
+	ExtMeta      []byte
+	AckSize      uint32 // The number of bytes that can be Acked to DCP
+}
+
+// UprStream is per stream data structure over an UPR Connection.
+type UprStream struct {
+	Vbucket   uint16 // Vbucket id
+	Vbuuid    uint64 // vbucket uuid
+	StartSeq  uint64 // start sequence number
+	EndSeq    uint64 // end sequence number
+	connected bool
+}
+
+const (
+	CompressionTypeStartMarker = iota // also means invalid
+	CompressionTypeNone        = iota
+	CompressionTypeSnappy      = iota
+	CompressionTypeEndMarker   = iota // also means invalid
+)
+
+// kv_engine/include/mcbp/protocol/datatype.h
+const (
+	JSONDataType   uint8 = 1
+	SnappyDataType uint8 = 2
+	XattrDataType  uint8 = 4
+)
+
+type UprFeatures struct {
+	Xattribute          bool
+	CompressionType     int
+	IncludeDeletionTime bool
+}
+
+/**
+ * Used to handle multiple concurrent calls UprRequestStream() by UprFeed clients
+ * It is expected that a client that calls UprRequestStream() more than once should issue
+ * different "opaque" (version) numbers
+ */
+type opaqueStreamMap map[uint16]*UprStream // opaque -> stream
+
+type vbStreamNegotiator struct {
+	vbHandshakeMap map[uint16]opaqueStreamMap // vbno -> opaqueStreamMap
+	mutex          sync.RWMutex
+}
+
+func (negotiator *vbStreamNegotiator) initialize() {
+	negotiator.mutex.Lock()
+	negotiator.vbHandshakeMap = make(map[uint16]opaqueStreamMap)
+	negotiator.mutex.Unlock()
+}
+
+func (negotiator *vbStreamNegotiator) registerRequest(vbno, opaque uint16, vbuuid, startSequence, endSequence uint64) {
+	negotiator.mutex.Lock()
+	defer negotiator.mutex.Unlock()
+
+	var osMap opaqueStreamMap
+	var ok bool
+	if osMap, ok = negotiator.vbHandshakeMap[vbno]; !ok {
+		osMap = make(opaqueStreamMap)
+		negotiator.vbHandshakeMap[vbno] = osMap
+	}
+
+	if _, ok = osMap[opaque]; !ok {
+		osMap[opaque] = &UprStream{
+			Vbucket:  vbno,
+			Vbuuid:   vbuuid,
+			StartSeq: startSequence,
+			EndSeq:   endSequence,
+		}
+	}
+}
+
+func (negotiator *vbStreamNegotiator) getStreamsCntFromMap(vbno uint16) int {
+	negotiator.mutex.RLock()
+	defer negotiator.mutex.RUnlock()
+
+	osmap, ok := negotiator.vbHandshakeMap[vbno]
+	if !ok {
+		return 0
+	} else {
+		return len(osmap)
+	}
+}
+
+func (negotiator *vbStreamNegotiator) getStreamFromMap(vbno, opaque uint16) (*UprStream, error) {
+	negotiator.mutex.RLock()
+	defer negotiator.mutex.RUnlock()
+
+	osmap, ok := negotiator.vbHandshakeMap[vbno]
+	if !ok {
+		return nil, fmt.Errorf("Error: stream for vb: %v does not exist", vbno)
+	}
+
+	stream, ok := osmap[opaque]
+	if !ok {
+		return nil, fmt.Errorf("Error: stream for vb: %v opaque: %v does not exist", vbno, opaque)
+	}
+	return stream, nil
+}
+
+func (negotiator *vbStreamNegotiator) deleteStreamFromMap(vbno, opaque uint16) {
+	negotiator.mutex.Lock()
+	defer negotiator.mutex.Unlock()
+
+	osmap, ok := negotiator.vbHandshakeMap[vbno]
+	if !ok {
+		return
+	}
+
+	delete(osmap, opaque)
+	if len(osmap) == 0 {
+		delete(negotiator.vbHandshakeMap, vbno)
+	}
+}
+
+func (negotiator *vbStreamNegotiator) handleStreamRequest(feed *UprFeed,
+	headerBuf [gomemcached.HDR_LEN]byte, pktPtr *gomemcached.MCRequest, bytesReceivedFromDCP int,
+	response *gomemcached.MCResponse) (*UprEvent, error) {
+	var event *UprEvent
+
+	if feed == nil || response == nil || pktPtr == nil {
+		return nil, errors.New("Invalid inputs")
+	}
+
+	// Get Stream from negotiator map
+	vbno := vbOpaque(response.Opaque)
+	opaque := appOpaque(response.Opaque)
+
+	stream, err := negotiator.getStreamFromMap(vbno, opaque)
+	if err != nil {
+		err = fmt.Errorf("Stream not found for vb %d appOpaque %v: %#v", vbno, appOpaque, *pktPtr)
+		logging.Errorf(err.Error())
+		return nil, err
+	}
+
+	status, rb, flog, err := handleStreamRequest(response, headerBuf[:])
+
+	if status == gomemcached.ROLLBACK {
+		event = makeUprEvent(*pktPtr, stream, bytesReceivedFromDCP)
+		event.Status = status
+		// rollback stream
+		logging.Infof("UPR_STREAMREQ with rollback %d for vb %d Failed: %v", rb, vbno, err)
+		negotiator.deleteStreamFromMap(vbno, opaque)
+	} else if status == gomemcached.SUCCESS {
+		event = makeUprEvent(*pktPtr, stream, bytesReceivedFromDCP)
+		event.Seqno = stream.StartSeq
+		event.FailoverLog = flog
+		event.Status = status
+		feed.activateStream(vbno, opaque, stream)
+		feed.negotiator.deleteStreamFromMap(vbno, opaque)
+		logging.Infof("UPR_STREAMREQ for vb %d successful", vbno)
+
+	} else if err != nil {
+		logging.Errorf("UPR_STREAMREQ for vbucket %d erro %s", vbno, err.Error())
+		event = &UprEvent{
+			Opcode:  gomemcached.UPR_STREAMREQ,
+			Status:  status,
+			VBucket: vbno,
+			Error:   err,
+		}
+		negotiator.deleteStreamFromMap(vbno, opaque)
+	}
+	return event, nil
+}
+
+func (negotiator *vbStreamNegotiator) cleanUpVbStreams(vbno uint16) {
+	negotiator.mutex.Lock()
+	defer negotiator.mutex.Unlock()
+
+	delete(negotiator.vbHandshakeMap, vbno)
+}
+
+// UprFeed represents an UPR feed. A feed contains a connection to a single
+// host and multiple vBuckets
+type UprFeed struct {
+	// lock for feed.vbstreams
+	muVbstreams sync.RWMutex
+	// lock for feed.closed
+	muClosed    sync.RWMutex
+	C           <-chan *UprEvent            // Exported channel for receiving UPR events
+	negotiator  vbStreamNegotiator          // Used for pre-vbstreams, concurrent vb stream negotiation
+	vbstreams   map[uint16]*UprStream       // official live vb->stream mapping
+	closer      chan bool                   // closer
+	conn        *Client                     // connection to UPR producer
+	Error       error                       // error
+	bytesRead   uint64                      // total bytes read on this connection
+	toAckBytes  uint32                      // bytes client has read
+	maxAckBytes uint32                      // Max buffer control ack bytes
+	stats       UprStats                    // Stats for upr client
+	transmitCh  chan *gomemcached.MCRequest // transmit command channel
+	transmitCl  chan bool                   //  closer channel for transmit go-routine
+	closed      bool                        // flag indicating whether the feed has been closed
+	// flag indicating whether client of upr feed will send ack to upr feed
+	// if flag is true, upr feed will use ack from client to determine whether/when to send ack to DCP
+	// if flag is false, upr feed will track how many bytes it has sent to client
+	// and use that to determine whether/when to send ack to DCP
+	ackByClient bool
+}
+
+// Exported interface - to allow for mocking
+type UprFeedIface interface {
+	Close()
+	Closed() bool
+	CloseStream(vbno, opaqueMSB uint16) error
+	GetError() error
+	GetUprStats() *UprStats
+	ClientAck(event *UprEvent) error
+	GetUprEventCh() <-chan *UprEvent
+	StartFeed() error
+	StartFeedWithConfig(datachan_len int) error
+	UprOpen(name string, sequence uint32, bufSize uint32) error
+	UprOpenWithXATTR(name string, sequence uint32, bufSize uint32) error
+	UprOpenWithFeatures(name string, sequence uint32, bufSize uint32, features UprFeatures) (error, UprFeatures)
+	UprRequestStream(vbno, opaqueMSB uint16, flags uint32, vuuid, startSequence, endSequence, snapStart, snapEnd uint64) error
+}
+
+type UprStats struct {
+	TotalBytes         uint64
+	TotalMutation      uint64
+	TotalBufferAckSent uint64
+	TotalSnapShot      uint64
+}
+
+// FailoverLog containing vvuid and sequnce number
+type FailoverLog [][2]uint64
+
+// error codes
+var ErrorInvalidLog = errors.New("couchbase.errorInvalidLog")
+
+func (flogp *FailoverLog) Latest() (vbuuid, seqno uint64, err error) {
+	if flogp != nil {
+		flog := *flogp
+		latest := flog[len(flog)-1]
+		return latest[0], latest[1], nil
+	}
+	return vbuuid, seqno, ErrorInvalidLog
+}
+
+func makeUprEvent(rq gomemcached.MCRequest, stream *UprStream, bytesReceivedFromDCP int) *UprEvent {
+	event := &UprEvent{
+		Opcode:   rq.Opcode,
+		VBucket:  stream.Vbucket,
+		VBuuid:   stream.Vbuuid,
+		Key:      rq.Key,
+		Value:    rq.Body,
+		Cas:      rq.Cas,
+		ExtMeta:  rq.ExtMeta,
+		DataType: rq.DataType,
+	}
+
+	// set AckSize for events that need to be acked to DCP,
+	// i.e., events with CommandCodes that need to be buffered in DCP
+	if _, ok := gomemcached.BufferedCommandCodeMap[rq.Opcode]; ok {
+		event.AckSize = uint32(bytesReceivedFromDCP)
+	}
+
+	// 16 LSBits are used by client library to encode vbucket number.
+	// 16 MSBits are left for application to multiplex on opaque value.
+	event.Opaque = appOpaque(rq.Opaque)
+
+	if len(rq.Extras) >= uprMutationExtraLen &&
+		event.Opcode == gomemcached.UPR_MUTATION {
+
+		event.Seqno = binary.BigEndian.Uint64(rq.Extras[:8])
+		event.RevSeqno = binary.BigEndian.Uint64(rq.Extras[8:16])
+		event.Flags = binary.BigEndian.Uint32(rq.Extras[16:20])
+		event.Expiry = binary.BigEndian.Uint32(rq.Extras[20:24])
+		event.LockTime = binary.BigEndian.Uint32(rq.Extras[24:28])
+		event.MetadataSize = binary.BigEndian.Uint16(rq.Extras[28:30])
+
+	} else if len(rq.Extras) >= uprDeletetionWithDeletionTimeExtraLen &&
+		event.Opcode == gomemcached.UPR_DELETION {
+
+		event.Seqno = binary.BigEndian.Uint64(rq.Extras[:8])
+		event.RevSeqno = binary.BigEndian.Uint64(rq.Extras[8:16])
+		event.Expiry = binary.BigEndian.Uint32(rq.Extras[16:20])
+
+	} else if len(rq.Extras) >= uprDeletetionExtraLen &&
+		event.Opcode == gomemcached.UPR_DELETION ||
+		event.Opcode == gomemcached.UPR_EXPIRATION {
+
+		event.Seqno = binary.BigEndian.Uint64(rq.Extras[:8])
+		event.RevSeqno = binary.BigEndian.Uint64(rq.Extras[8:16])
+		event.MetadataSize = binary.BigEndian.Uint16(rq.Extras[16:18])
+
+	} else if len(rq.Extras) >= uprSnapshotExtraLen &&
+		event.Opcode == gomemcached.UPR_SNAPSHOT {
+
+		event.SnapstartSeq = binary.BigEndian.Uint64(rq.Extras[:8])
+		event.SnapendSeq = binary.BigEndian.Uint64(rq.Extras[8:16])
+		event.SnapshotType = binary.BigEndian.Uint32(rq.Extras[16:20])
+	}
+
+	return event
+}
+
+func (event *UprEvent) String() string {
+	name := gomemcached.CommandNames[event.Opcode]
+	if name == "" {
+		name = fmt.Sprintf("#%d", event.Opcode)
+	}
+	return name
+}
+
+func (event *UprEvent) IsSnappyDataType() bool {
+	return event.Opcode == gomemcached.UPR_MUTATION && (event.DataType&SnappyDataType > 0)
+}
+
+func (feed *UprFeed) sendCommands(mc *Client) {
+	transmitCh := feed.transmitCh
+	transmitCl := feed.transmitCl
+loop:
+	for {
+		select {
+		case command := <-transmitCh:
+			if err := mc.Transmit(command); err != nil {
+				logging.Errorf("Failed to transmit command %s. Error %s", command.Opcode.String(), err.Error())
+				// get feed to close and runFeed routine to exit
+				feed.Close()
+				break loop
+			}
+
+		case <-transmitCl:
+			break loop
+		}
+	}
+
+	// After sendCommands exits, write to transmitCh will block forever
+	// when we write to transmitCh, e.g., at CloseStream(), we need to check feed closure to have an exit route
+
+	logging.Infof("sendCommands exiting")
+}
+
+// Sets the specified stream as the connected stream for this vbno, and also cleans up negotiator
+func (feed *UprFeed) activateStream(vbno, opaque uint16, stream *UprStream) error {
+	feed.muVbstreams.Lock()
+	defer feed.muVbstreams.Unlock()
+
+	// Set this stream as the officially connected stream for this vb
+	stream.connected = true
+	feed.vbstreams[vbno] = stream
+	return nil
+}
+
+func (feed *UprFeed) cleanUpVbStream(vbno uint16) {
+	feed.muVbstreams.Lock()
+	defer feed.muVbstreams.Unlock()
+
+	delete(feed.vbstreams, vbno)
+}
+
+// NewUprFeed creates a new UPR Feed.
+// TODO: Describe side-effects on bucket instance and its connection pool.
+func (mc *Client) NewUprFeed() (*UprFeed, error) {
+	return mc.NewUprFeedWithConfig(false /*ackByClient*/)
+}
+
+func (mc *Client) NewUprFeedWithConfig(ackByClient bool) (*UprFeed, error) {
+
+	feed := &UprFeed{
+		conn:        mc,
+		closer:      make(chan bool, 1),
+		vbstreams:   make(map[uint16]*UprStream),
+		transmitCh:  make(chan *gomemcached.MCRequest),
+		transmitCl:  make(chan bool),
+		ackByClient: ackByClient,
+	}
+
+	feed.negotiator.initialize()
+
+	go feed.sendCommands(mc)
+	return feed, nil
+}
+
+func (mc *Client) NewUprFeedIface() (UprFeedIface, error) {
+	return mc.NewUprFeed()
+}
+
+func (mc *Client) NewUprFeedWithConfigIface(ackByClient bool) (UprFeedIface, error) {
+	return mc.NewUprFeedWithConfig(ackByClient)
+}
+
+func doUprOpen(mc *Client, name string, sequence uint32, features UprFeatures) error {
+	rq := &gomemcached.MCRequest{
+		Opcode: gomemcached.UPR_OPEN,
+		Key:    []byte(name),
+		Opaque: getUprOpenCtrlOpaque(),
+	}
+
+	rq.Extras = make([]byte, 8)
+	binary.BigEndian.PutUint32(rq.Extras[:4], sequence)
+
+	// opens a producer type connection
+	flags := gomemcached.DCP_PRODUCER
+	if features.Xattribute {
+		flags = flags | gomemcached.DCP_OPEN_INCLUDE_XATTRS
+	}
+	if features.IncludeDeletionTime {
+		flags = flags | gomemcached.DCP_OPEN_INCLUDE_DELETE_TIMES
+	}
+	binary.BigEndian.PutUint32(rq.Extras[4:], flags)
+
+	return sendMcRequestSync(mc, rq)
+}
+
+// Synchronously send a memcached request and wait for the response
+func sendMcRequestSync(mc *Client, req *gomemcached.MCRequest) error {
+	if err := mc.Transmit(req); err != nil {
+		return err
+	}
+
+	if res, err := mc.Receive(); err != nil {
+		return err
+	} else if req.Opcode != res.Opcode {
+		return fmt.Errorf("unexpected #opcode sent %v received %v", req.Opcode, res.Opaque)
+	} else if req.Opaque != res.Opaque {
+		return fmt.Errorf("opaque mismatch, sent %v received %v", req.Opaque, res.Opaque)
+	} else if res.Status != gomemcached.SUCCESS {
+		return fmt.Errorf("error %v", res.Status)
+	}
+	return nil
+}
+
+// UprOpen to connect with a UPR producer.
+// Name: name of te UPR connection
+// sequence: sequence number for the connection
+// bufsize: max size of the application
+func (feed *UprFeed) UprOpen(name string, sequence uint32, bufSize uint32) error {
+	var allFeaturesDisabled UprFeatures
+	err, _ := feed.uprOpen(name, sequence, bufSize, allFeaturesDisabled)
+	return err
+}
+
+// UprOpen with XATTR enabled.
+func (feed *UprFeed) UprOpenWithXATTR(name string, sequence uint32, bufSize uint32) error {
+	var onlyXattrEnabled UprFeatures
+	onlyXattrEnabled.Xattribute = true
+	err, _ := feed.uprOpen(name, sequence, bufSize, onlyXattrEnabled)
+	return err
+}
+
+func (feed *UprFeed) UprOpenWithFeatures(name string, sequence uint32, bufSize uint32, features UprFeatures) (error, UprFeatures) {
+	return feed.uprOpen(name, sequence, bufSize, features)
+}
+
+func (feed *UprFeed) uprOpen(name string, sequence uint32, bufSize uint32, features UprFeatures) (err error, activatedFeatures UprFeatures) {
+	mc := feed.conn
+
+	// First set this to an invalid value to state that the method hasn't gotten to executing this control yet
+	activatedFeatures.CompressionType = CompressionTypeEndMarker
+
+	if err = doUprOpen(mc, name, sequence, features); err != nil {
+		return
+	}
+
+	activatedFeatures.Xattribute = features.Xattribute
+
+	// send a UPR control message to set the window size for the this connection
+	if bufSize > 0 {
+		rq := &gomemcached.MCRequest{
+			Opcode: gomemcached.UPR_CONTROL,
+			Key:    []byte("connection_buffer_size"),
+			Body:   []byte(strconv.Itoa(int(bufSize))),
+			Opaque: getUprOpenCtrlOpaque(),
+		}
+		err = sendMcRequestSync(feed.conn, rq)
+		if err != nil {
+			return
+		}
+		feed.maxAckBytes = uint32(bufferAckThreshold * float32(bufSize))
+	}
+
+	// enable noop and set noop interval
+	rq := &gomemcached.MCRequest{
+		Opcode: gomemcached.UPR_CONTROL,
+		Key:    []byte("enable_noop"),
+		Body:   []byte("true"),
+		Opaque: getUprOpenCtrlOpaque(),
+	}
+	err = sendMcRequestSync(feed.conn, rq)
+	if err != nil {
+		return
+	}
+
+	rq = &gomemcached.MCRequest{
+		Opcode: gomemcached.UPR_CONTROL,
+		Key:    []byte("set_noop_interval"),
+		Body:   []byte(strconv.Itoa(int(uprDefaultNoopInterval))),
+		Opaque: getUprOpenCtrlOpaque(),
+	}
+	err = sendMcRequestSync(feed.conn, rq)
+	if err != nil {
+		return
+	}
+
+	if features.CompressionType == CompressionTypeSnappy {
+		activatedFeatures.CompressionType = CompressionTypeNone
+		rq = &gomemcached.MCRequest{
+			Opcode: gomemcached.UPR_CONTROL,
+			Key:    []byte("force_value_compression"),
+			Body:   []byte("true"),
+			Opaque: getUprOpenCtrlOpaque(),
+		}
+		err = sendMcRequestSync(feed.conn, rq)
+	} else if features.CompressionType == CompressionTypeEndMarker {
+		err = fmt.Errorf("UPR_CONTROL Failed - Invalid CompressionType: %v", features.CompressionType)
+	}
+	if err != nil {
+		return
+	}
+	activatedFeatures.CompressionType = features.CompressionType
+
+	return
+}
+
+// UprGetFailoverLog for given list of vbuckets.
+func (mc *Client) UprGetFailoverLog(
+	vb []uint16) (map[uint16]*FailoverLog, error) {
+
+	rq := &gomemcached.MCRequest{
+		Opcode: gomemcached.UPR_FAILOVERLOG,
+		Opaque: opaqueFailover,
+	}
+
+	var allFeaturesDisabled UprFeatures
+	if err := doUprOpen(mc, "FailoverLog", 0, allFeaturesDisabled); err != nil {
+		return nil, fmt.Errorf("UPR_OPEN Failed %s", err.Error())
+	}
+
+	failoverLogs := make(map[uint16]*FailoverLog)
+	for _, vBucket := range vb {
+		rq.VBucket = vBucket
+		if err := mc.Transmit(rq); err != nil {
+			return nil, err
+		}
+		res, err := mc.Receive()
+
+		if err != nil {
+			return nil, fmt.Errorf("failed to receive %s", err.Error())
+		} else if res.Opcode != gomemcached.UPR_FAILOVERLOG || res.Status != gomemcached.SUCCESS {
+			return nil, fmt.Errorf("unexpected #opcode %v", res.Opcode)
+		}
+
+		flog, err := parseFailoverLog(res.Body)
+		if err != nil {
+			return nil, fmt.Errorf("unable to parse failover logs for vb %d", vb)
+		}
+		failoverLogs[vBucket] = flog
+	}
+
+	return failoverLogs, nil
+}
+
+// UprRequestStream for a single vbucket.
+func (feed *UprFeed) UprRequestStream(vbno, opaqueMSB uint16, flags uint32,
+	vuuid, startSequence, endSequence, snapStart, snapEnd uint64) error {
+
+	rq := &gomemcached.MCRequest{
+		Opcode:  gomemcached.UPR_STREAMREQ,
+		VBucket: vbno,
+		Opaque:  composeOpaque(vbno, opaqueMSB),
+	}
+
+	rq.Extras = make([]byte, 48) // #Extras
+	binary.BigEndian.PutUint32(rq.Extras[:4], flags)
+	binary.BigEndian.PutUint32(rq.Extras[4:8], uint32(0))
+	binary.BigEndian.PutUint64(rq.Extras[8:16], startSequence)
+	binary.BigEndian.PutUint64(rq.Extras[16:24], endSequence)
+	binary.BigEndian.PutUint64(rq.Extras[24:32], vuuid)
+	binary.BigEndian.PutUint64(rq.Extras[32:40], snapStart)
+	binary.BigEndian.PutUint64(rq.Extras[40:48], snapEnd)
+
+	feed.negotiator.registerRequest(vbno, opaqueMSB, vuuid, startSequence, endSequence)
+	// Any client that has ever called this method, regardless of return code,
+	// should expect a potential UPR_CLOSESTREAM message due to this new map entry prior to Transmit.
+
+	if err := feed.conn.Transmit(rq); err != nil {
+		logging.Errorf("Error in StreamRequest %s", err.Error())
+		// If an error occurs during transmit, then the UPRFeed will keep the stream
+		// in the vbstreams map. This is to prevent nil lookup from any previously
+		// sent stream requests.
+		return err
+	}
+
+	return nil
+}
+
+// CloseStream for specified vbucket.
+func (feed *UprFeed) CloseStream(vbno, opaqueMSB uint16) error {
+
+	err := feed.validateCloseStream(vbno)
+	if err != nil {
+		logging.Infof("CloseStream for %v has been skipped because of error %v", vbno, err)
+		return err
+	}
+
+	closeStream := &gomemcached.MCRequest{
+		Opcode:  gomemcached.UPR_CLOSESTREAM,
+		VBucket: vbno,
+		Opaque:  composeOpaque(vbno, opaqueMSB),
+	}
+
+	feed.writeToTransmitCh(closeStream)
+
+	return nil
+}
+
+func (feed *UprFeed) GetUprEventCh() <-chan *UprEvent {
+	return feed.C
+}
+
+func (feed *UprFeed) GetError() error {
+	return feed.Error
+}
+
+func (feed *UprFeed) validateCloseStream(vbno uint16) error {
+	feed.muVbstreams.RLock()
+	nilVbStream := feed.vbstreams[vbno] == nil
+	feed.muVbstreams.RUnlock()
+
+	if nilVbStream && (feed.negotiator.getStreamsCntFromMap(vbno) == 0) {
+		return fmt.Errorf("Stream for vb %d has not been requested", vbno)
+	}
+
+	return nil
+}
+
+func (feed *UprFeed) writeToTransmitCh(rq *gomemcached.MCRequest) error {
+	// write to transmitCh may block forever if sendCommands has exited
+	// check for feed closure to have an exit route in this case
+	select {
+	case <-feed.closer:
+		errMsg := fmt.Sprintf("Abort sending request to transmitCh because feed has been closed. request=%v", rq)
+		logging.Infof(errMsg)
+		return errors.New(errMsg)
+	case feed.transmitCh <- rq:
+	}
+	return nil
+}
+
+// StartFeed to start the upper feed.
+func (feed *UprFeed) StartFeed() error {
+	return feed.StartFeedWithConfig(10)
+}
+
+func (feed *UprFeed) StartFeedWithConfig(datachan_len int) error {
+	ch := make(chan *UprEvent, datachan_len)
+	feed.C = ch
+	go feed.runFeed(ch)
+	return nil
+}
+
+func parseFailoverLog(body []byte) (*FailoverLog, error) {
+
+	if len(body)%16 != 0 {
+		err := fmt.Errorf("invalid body length %v, in failover-log", len(body))
+		return nil, err
+	}
+	log := make(FailoverLog, len(body)/16)
+	for i, j := 0, 0; i < len(body); i += 16 {
+		vuuid := binary.BigEndian.Uint64(body[i : i+8])
+		seqno := binary.BigEndian.Uint64(body[i+8 : i+16])
+		log[j] = [2]uint64{vuuid, seqno}
+		j++
+	}
+	return &log, nil
+}
+
+func handleStreamRequest(
+	res *gomemcached.MCResponse,
+	headerBuf []byte,
+) (gomemcached.Status, uint64, *FailoverLog, error) {
+
+	var rollback uint64
+	var err error
+
+	switch {
+	case res.Status == gomemcached.ROLLBACK:
+		logging.Infof("Rollback response. body=%v, headerBuf=%v\n", res.Body, headerBuf)
+		rollback = binary.BigEndian.Uint64(res.Body)
+		logging.Infof("Rollback seqno is %v for response with opaque %v\n", rollback, res.Opaque)
+		return res.Status, rollback, nil, nil
+
+	case res.Status != gomemcached.SUCCESS:
+		err = fmt.Errorf("unexpected status %v for response with opaque %v", res.Status, res.Opaque)
+		return res.Status, 0, nil, err
+	}
+
+	flog, err := parseFailoverLog(res.Body[:])
+	return res.Status, rollback, flog, err
+}
+
+// generate stream end responses for all active vb streams
+func (feed *UprFeed) doStreamClose(ch chan *UprEvent) {
+	feed.muVbstreams.RLock()
+
+	uprEvents := make([]*UprEvent, len(feed.vbstreams))
+	index := 0
+	for vbno, stream := range feed.vbstreams {
+		uprEvent := &UprEvent{
+			VBucket: vbno,
+			VBuuid:  stream.Vbuuid,
+			Opcode:  gomemcached.UPR_STREAMEND,
+		}
+		uprEvents[index] = uprEvent
+		index++
+	}
+
+	// release the lock before sending uprEvents to ch, which may block
+	feed.muVbstreams.RUnlock()
+
+loop:
+	for _, uprEvent := range uprEvents {
+		select {
+		case ch <- uprEvent:
+		case <-feed.closer:
+			logging.Infof("Feed has been closed. Aborting doStreamClose.")
+			break loop
+		}
+	}
+}
+
+func (feed *UprFeed) runFeed(ch chan *UprEvent) {
+	defer close(ch)
+	var headerBuf [gomemcached.HDR_LEN]byte
+	var pkt gomemcached.MCRequest
+	var event *UprEvent
+
+	mc := feed.conn.Hijack()
+	uprStats := &feed.stats
+
+loop:
+	for {
+		select {
+		case <-feed.closer:
+			logging.Infof("Feed has been closed. Exiting.")
+			break loop
+		default:
+			bytes, err := pkt.Receive(mc, headerBuf[:])
+			if err != nil {
+				logging.Errorf("Error in receive %s", err.Error())
+				feed.Error = err
+				// send all the stream close messages to the client
+				feed.doStreamClose(ch)
+				break loop
+			} else {
+				event = nil
+				res := &gomemcached.MCResponse{
+					Opcode: pkt.Opcode,
+					Cas:    pkt.Cas,
+					Opaque: pkt.Opaque,
+					Status: gomemcached.Status(pkt.VBucket),
+					Extras: pkt.Extras,
+					Key:    pkt.Key,
+					Body:   pkt.Body,
+				}
+
+				vb := vbOpaque(pkt.Opaque)
+				appOpaque := appOpaque(pkt.Opaque)
+				uprStats.TotalBytes = uint64(bytes)
+
+				feed.muVbstreams.RLock()
+				stream := feed.vbstreams[vb]
+				feed.muVbstreams.RUnlock()
+
+				switch pkt.Opcode {
+				case gomemcached.UPR_STREAMREQ:
+					event, err = feed.negotiator.handleStreamRequest(feed, headerBuf, &pkt, bytes, res)
+					if err != nil {
+						logging.Infof(err.Error())
+						break loop
+					}
+				case gomemcached.UPR_MUTATION,
+					gomemcached.UPR_DELETION,
+					gomemcached.UPR_EXPIRATION:
+					if stream == nil {
+						logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
+						break loop
+					}
+					event = makeUprEvent(pkt, stream, bytes)
+					uprStats.TotalMutation++
+
+				case gomemcached.UPR_STREAMEND:
+					if stream == nil {
+						logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
+						break loop
+					}
+					//stream has ended
+					event = makeUprEvent(pkt, stream, bytes)
+					logging.Infof("Stream Ended for vb %d", vb)
+
+					feed.negotiator.deleteStreamFromMap(vb, appOpaque)
+					feed.cleanUpVbStream(vb)
+
+				case gomemcached.UPR_SNAPSHOT:
+					if stream == nil {
+						logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
+						break loop
+					}
+					// snapshot marker
+					event = makeUprEvent(pkt, stream, bytes)
+					uprStats.TotalSnapShot++
+
+				case gomemcached.UPR_FLUSH:
+					if stream == nil {
+						logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
+						break loop
+					}
+					// special processing for flush ?
+					event = makeUprEvent(pkt, stream, bytes)
+
+				case gomemcached.UPR_CLOSESTREAM:
+					if stream == nil {
+						logging.Infof("Stream not found for vb %d: %#v", vb, pkt)
+						break loop
+					}
+					event = makeUprEvent(pkt, stream, bytes)
+					event.Opcode = gomemcached.UPR_STREAMEND // opcode re-write !!
+					logging.Infof("Stream Closed for vb %d StreamEnd simulated", vb)
+
+					feed.negotiator.deleteStreamFromMap(vb, appOpaque)
+					feed.cleanUpVbStream(vb)
+
+				case gomemcached.UPR_ADDSTREAM:
+					logging.Infof("Opcode %v not implemented", pkt.Opcode)
+
+				case gomemcached.UPR_CONTROL, gomemcached.UPR_BUFFERACK:
+					if res.Status != gomemcached.SUCCESS {
+						logging.Infof("Opcode %v received status %d", pkt.Opcode.String(), res.Status)
+					}
+
+				case gomemcached.UPR_NOOP:
+					// send a NOOP back
+					noop := &gomemcached.MCResponse{
+						Opcode: gomemcached.UPR_NOOP,
+						Opaque: pkt.Opaque,
+					}
+
+					if err := feed.conn.TransmitResponse(noop); err != nil {
+						logging.Warnf("failed to transmit command %s. Error %s", noop.Opcode.String(), err.Error())
+					}
+				default:
+					logging.Infof("Recived an unknown response for vbucket %d", vb)
+				}
+			}
+
+			if event != nil {
+				select {
+				case ch <- event:
+				case <-feed.closer:
+					logging.Infof("Feed has been closed. Skip sending events. Exiting.")
+					break loop
+				}
+
+				feed.muVbstreams.RLock()
+				l := len(feed.vbstreams)
+				feed.muVbstreams.RUnlock()
+
+				if event.Opcode == gomemcached.UPR_CLOSESTREAM && l == 0 {
+					logging.Infof("No more streams")
+				}
+			}
+
+			if !feed.ackByClient {
+				// if client does not ack, do the ack check now
+				feed.sendBufferAckIfNeeded(event)
+			}
+		}
+	}
+
+	// make sure that feed is closed before we signal transmitCl and exit runFeed
+	feed.Close()
+
+	close(feed.transmitCl)
+	logging.Infof("runFeed exiting")
+}
+
+// Client, after completing processing of an UprEvent, need to call this API to notify UprFeed,
+// so that UprFeed can update its ack bytes stats and send ack to DCP if needed
+// Client needs to set ackByClient flag to true in NewUprFeedWithConfig() call as a prerequisite for this call to work
+// This API is not thread safe. Caller should NOT have more than one go rountine calling this API
+func (feed *UprFeed) ClientAck(event *UprEvent) error {
+	if !feed.ackByClient {
+		return errors.New("Upr feed does not have ackByclient flag set")
+	}
+	feed.sendBufferAckIfNeeded(event)
+	return nil
+}
+
+// increment ack bytes if the event needs to be acked to DCP
+// send buffer ack if enough ack bytes have been accumulated
+func (feed *UprFeed) sendBufferAckIfNeeded(event *UprEvent) {
+	if event == nil || event.AckSize == 0 {
+		// this indicates that there is no need to ack to DCP
+		return
+	}
+
+	totalBytes := feed.toAckBytes + event.AckSize
+	if totalBytes > feed.maxAckBytes {
+		feed.toAckBytes = 0
+		feed.sendBufferAck(totalBytes)
+	} else {
+		feed.toAckBytes = totalBytes
+	}
+}
+
+// send buffer ack to dcp
+func (feed *UprFeed) sendBufferAck(sendSize uint32) {
+	bufferAck := &gomemcached.MCRequest{
+		Opcode: gomemcached.UPR_BUFFERACK,
+	}
+	bufferAck.Extras = make([]byte, 4)
+	binary.BigEndian.PutUint32(bufferAck.Extras[:4], uint32(sendSize))
+	feed.writeToTransmitCh(bufferAck)
+	feed.stats.TotalBufferAckSent++
+}
+
+func (feed *UprFeed) GetUprStats() *UprStats {
+	return &feed.stats
+}
+
+func composeOpaque(vbno, opaqueMSB uint16) uint32 {
+	return (uint32(opaqueMSB) << 16) | uint32(vbno)
+}
+
+func getUprOpenCtrlOpaque() uint32 {
+	return atomic.AddUint32(&opaqueOpenCtrlWell, 1)
+}
+
+func appOpaque(opq32 uint32) uint16 {
+	return uint16((opq32 & 0xFFFF0000) >> 16)
+}
+
+func vbOpaque(opq32 uint32) uint16 {
+	return uint16(opq32 & 0xFFFF)
+}
+
+// Close this UprFeed.
+func (feed *UprFeed) Close() {
+	feed.muClosed.Lock()
+	defer feed.muClosed.Unlock()
+	if !feed.closed {
+		close(feed.closer)
+		feed.closed = true
+		feed.negotiator.initialize()
+	}
+}
+
+// check if the UprFeed has been closed
+func (feed *UprFeed) Closed() bool {
+	feed.muClosed.RLock()
+	defer feed.muClosed.RUnlock()
+	return feed.closed
+}
diff --git a/vendor/github.com/couchbase/gomemcached/mc_constants.go b/vendor/github.com/couchbase/gomemcached/mc_constants.go
new file mode 100644
index 0000000000..1d5027d16c
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/mc_constants.go
@@ -0,0 +1,335 @@
+// Package gomemcached is binary protocol packet formats and constants.
+package gomemcached
+
+import (
+	"fmt"
+)
+
+const (
+	REQ_MAGIC = 0x80
+	RES_MAGIC = 0x81
+)
+
+// CommandCode for memcached packets.
+type CommandCode uint8
+
+const (
+	GET        = CommandCode(0x00)
+	SET        = CommandCode(0x01)
+	ADD        = CommandCode(0x02)
+	REPLACE    = CommandCode(0x03)
+	DELETE     = CommandCode(0x04)
+	INCREMENT  = CommandCode(0x05)
+	DECREMENT  = CommandCode(0x06)
+	QUIT       = CommandCode(0x07)
+	FLUSH      = CommandCode(0x08)
+	GETQ       = CommandCode(0x09)
+	NOOP       = CommandCode(0x0a)
+	VERSION    = CommandCode(0x0b)
+	GETK       = CommandCode(0x0c)
+	GETKQ      = CommandCode(0x0d)
+	APPEND     = CommandCode(0x0e)
+	PREPEND    = CommandCode(0x0f)
+	STAT       = CommandCode(0x10)
+	SETQ       = CommandCode(0x11)
+	ADDQ       = CommandCode(0x12)
+	REPLACEQ   = CommandCode(0x13)
+	DELETEQ    = CommandCode(0x14)
+	INCREMENTQ = CommandCode(0x15)
+	DECREMENTQ = CommandCode(0x16)
+	QUITQ      = CommandCode(0x17)
+	FLUSHQ     = CommandCode(0x18)
+	APPENDQ    = CommandCode(0x19)
+	AUDIT      = CommandCode(0x27)
+	PREPENDQ   = CommandCode(0x1a)
+	GAT        = CommandCode(0x1d)
+	HELLO      = CommandCode(0x1f)
+	RGET       = CommandCode(0x30)
+	RSET       = CommandCode(0x31)
+	RSETQ      = CommandCode(0x32)
+	RAPPEND    = CommandCode(0x33)
+	RAPPENDQ   = CommandCode(0x34)
+	RPREPEND   = CommandCode(0x35)
+	RPREPENDQ  = CommandCode(0x36)
+	RDELETE    = CommandCode(0x37)
+	RDELETEQ   = CommandCode(0x38)
+	RINCR      = CommandCode(0x39)
+	RINCRQ     = CommandCode(0x3a)
+	RDECR      = CommandCode(0x3b)
+	RDECRQ     = CommandCode(0x3c)
+
+	SASL_LIST_MECHS = CommandCode(0x20)
+	SASL_AUTH       = CommandCode(0x21)
+	SASL_STEP       = CommandCode(0x22)
+
+	SET_VBUCKET = CommandCode(0x3d)
+
+	TAP_CONNECT          = CommandCode(0x40) // Client-sent request to initiate Tap feed
+	TAP_MUTATION         = CommandCode(0x41) // Notification of a SET/ADD/REPLACE/etc. on the server
+	TAP_DELETE           = CommandCode(0x42) // Notification of a DELETE on the server
+	TAP_FLUSH            = CommandCode(0x43) // Replicates a flush_all command
+	TAP_OPAQUE           = CommandCode(0x44) // Opaque control data from the engine
+	TAP_VBUCKET_SET      = CommandCode(0x45) // Sets state of vbucket in receiver (used in takeover)
+	TAP_CHECKPOINT_START = CommandCode(0x46) // Notifies start of new checkpoint
+	TAP_CHECKPOINT_END   = CommandCode(0x47) // Notifies end of checkpoint
+
+	UPR_OPEN        = CommandCode(0x50) // Open a UPR connection with a name
+	UPR_ADDSTREAM   = CommandCode(0x51) // Sent by ebucketMigrator to UPR Consumer
+	UPR_CLOSESTREAM = CommandCode(0x52) // Sent by eBucketMigrator to UPR Consumer
+	UPR_FAILOVERLOG = CommandCode(0x54) // Request failover logs
+	UPR_STREAMREQ   = CommandCode(0x53) // Stream request from consumer to producer
+	UPR_STREAMEND   = CommandCode(0x55) // Sent by producer when it has no more messages to stream
+	UPR_SNAPSHOT    = CommandCode(0x56) // Start of a new snapshot
+	UPR_MUTATION    = CommandCode(0x57) // Key mutation
+	UPR_DELETION    = CommandCode(0x58) // Key deletion
+	UPR_EXPIRATION  = CommandCode(0x59) // Key expiration
+	UPR_FLUSH       = CommandCode(0x5a) // Delete all the data for a vbucket
+	UPR_NOOP        = CommandCode(0x5c) // UPR NOOP
+	UPR_BUFFERACK   = CommandCode(0x5d) // UPR Buffer Acknowledgement
+	UPR_CONTROL     = CommandCode(0x5e) // Set flow control params
+
+	SELECT_BUCKET = CommandCode(0x89) // Select bucket
+
+	OBSERVE_SEQNO = CommandCode(0x91) // Sequence Number based Observe
+	OBSERVE       = CommandCode(0x92)
+
+	GET_META            = CommandCode(0xA0) // Get meta. returns with expiry, flags, cas etc
+	SUBDOC_GET          = CommandCode(0xc5) // Get subdoc. Returns with xattrs
+	SUBDOC_MULTI_LOOKUP = CommandCode(0xd0) // Multi lookup. Doc xattrs and meta.
+)
+
+// command codes that are counted toward DCP control buffer
+// when DCP clients receive DCP messages with these command codes, they need to provide acknowledgement
+var BufferedCommandCodeMap = map[CommandCode]bool{
+	SET_VBUCKET:    true,
+	UPR_STREAMEND:  true,
+	UPR_SNAPSHOT:   true,
+	UPR_MUTATION:   true,
+	UPR_DELETION:   true,
+	UPR_EXPIRATION: true}
+
+// Status field for memcached response.
+type Status uint16
+
+// Matches with protocol_binary.h as source of truth
+const (
+	SUCCESS         = Status(0x00)
+	KEY_ENOENT      = Status(0x01)
+	KEY_EEXISTS     = Status(0x02)
+	E2BIG           = Status(0x03)
+	EINVAL          = Status(0x04)
+	NOT_STORED      = Status(0x05)
+	DELTA_BADVAL    = Status(0x06)
+	NOT_MY_VBUCKET  = Status(0x07)
+	NO_BUCKET       = Status(0x08)
+	LOCKED          = Status(0x09)
+	AUTH_STALE      = Status(0x1f)
+	AUTH_ERROR      = Status(0x20)
+	AUTH_CONTINUE   = Status(0x21)
+	ERANGE          = Status(0x22)
+	ROLLBACK        = Status(0x23)
+	EACCESS         = Status(0x24)
+	NOT_INITIALIZED = Status(0x25)
+	UNKNOWN_COMMAND = Status(0x81)
+	ENOMEM          = Status(0x82)
+	NOT_SUPPORTED   = Status(0x83)
+	EINTERNAL       = Status(0x84)
+	EBUSY           = Status(0x85)
+	TMPFAIL         = Status(0x86)
+
+	// SUBDOC
+	SUBDOC_PATH_NOT_FOUND             = Status(0xc0)
+	SUBDOC_BAD_MULTI                  = Status(0xcc)
+	SUBDOC_MULTI_PATH_FAILURE_DELETED = Status(0xd3)
+)
+
+// for log redaction
+const (
+	UdTagBegin = "<ud>"
+	UdTagEnd   = "</ud>"
+)
+
+var isFatal = map[Status]bool{
+	DELTA_BADVAL:  true,
+	NO_BUCKET:     true,
+	AUTH_STALE:    true,
+	AUTH_ERROR:    true,
+	ERANGE:        true,
+	ROLLBACK:      true,
+	EACCESS:       true,
+	ENOMEM:        true,
+	NOT_SUPPORTED: true,
+}
+
+// the producer/consumer bit in dcp flags
+var DCP_PRODUCER uint32 = 0x01
+
+// the include XATTRS bit in dcp flags
+var DCP_OPEN_INCLUDE_XATTRS uint32 = 0x04
+
+// the include deletion time bit in dcp flags
+var DCP_OPEN_INCLUDE_DELETE_TIMES uint32 = 0x20
+
+// Datatype to Include XATTRS in SUBDOC GET
+var SUBDOC_FLAG_XATTR uint8 = 0x04
+
+// MCItem is an internal representation of an item.
+type MCItem struct {
+	Cas               uint64
+	Flags, Expiration uint32
+	Data              []byte
+}
+
+// Number of bytes in a binary protocol header.
+const HDR_LEN = 24
+
+// Mapping of CommandCode -> name of command (not exhaustive)
+var CommandNames map[CommandCode]string
+
+// StatusNames human readable names for memcached response.
+var StatusNames map[Status]string
+
+func init() {
+	CommandNames = make(map[CommandCode]string)
+	CommandNames[GET] = "GET"
+	CommandNames[SET] = "SET"
+	CommandNames[ADD] = "ADD"
+	CommandNames[REPLACE] = "REPLACE"
+	CommandNames[DELETE] = "DELETE"
+	CommandNames[INCREMENT] = "INCREMENT"
+	CommandNames[DECREMENT] = "DECREMENT"
+	CommandNames[QUIT] = "QUIT"
+	CommandNames[FLUSH] = "FLUSH"
+	CommandNames[GETQ] = "GETQ"
+	CommandNames[NOOP] = "NOOP"
+	CommandNames[VERSION] = "VERSION"
+	CommandNames[GETK] = "GETK"
+	CommandNames[GETKQ] = "GETKQ"
+	CommandNames[APPEND] = "APPEND"
+	CommandNames[PREPEND] = "PREPEND"
+	CommandNames[STAT] = "STAT"
+	CommandNames[SETQ] = "SETQ"
+	CommandNames[ADDQ] = "ADDQ"
+	CommandNames[REPLACEQ] = "REPLACEQ"
+	CommandNames[DELETEQ] = "DELETEQ"
+	CommandNames[INCREMENTQ] = "INCREMENTQ"
+	CommandNames[DECREMENTQ] = "DECREMENTQ"
+	CommandNames[QUITQ] = "QUITQ"
+	CommandNames[FLUSHQ] = "FLUSHQ"
+	CommandNames[APPENDQ] = "APPENDQ"
+	CommandNames[PREPENDQ] = "PREPENDQ"
+	CommandNames[RGET] = "RGET"
+	CommandNames[RSET] = "RSET"
+	CommandNames[RSETQ] = "RSETQ"
+	CommandNames[RAPPEND] = "RAPPEND"
+	CommandNames[RAPPENDQ] = "RAPPENDQ"
+	CommandNames[RPREPEND] = "RPREPEND"
+	CommandNames[RPREPENDQ] = "RPREPENDQ"
+	CommandNames[RDELETE] = "RDELETE"
+	CommandNames[RDELETEQ] = "RDELETEQ"
+	CommandNames[RINCR] = "RINCR"
+	CommandNames[RINCRQ] = "RINCRQ"
+	CommandNames[RDECR] = "RDECR"
+	CommandNames[RDECRQ] = "RDECRQ"
+
+	CommandNames[SASL_LIST_MECHS] = "SASL_LIST_MECHS"
+	CommandNames[SASL_AUTH] = "SASL_AUTH"
+	CommandNames[SASL_STEP] = "SASL_STEP"
+
+	CommandNames[TAP_CONNECT] = "TAP_CONNECT"
+	CommandNames[TAP_MUTATION] = "TAP_MUTATION"
+	CommandNames[TAP_DELETE] = "TAP_DELETE"
+	CommandNames[TAP_FLUSH] = "TAP_FLUSH"
+	CommandNames[TAP_OPAQUE] = "TAP_OPAQUE"
+	CommandNames[TAP_VBUCKET_SET] = "TAP_VBUCKET_SET"
+	CommandNames[TAP_CHECKPOINT_START] = "TAP_CHECKPOINT_START"
+	CommandNames[TAP_CHECKPOINT_END] = "TAP_CHECKPOINT_END"
+
+	CommandNames[UPR_OPEN] = "UPR_OPEN"
+	CommandNames[UPR_ADDSTREAM] = "UPR_ADDSTREAM"
+	CommandNames[UPR_CLOSESTREAM] = "UPR_CLOSESTREAM"
+	CommandNames[UPR_FAILOVERLOG] = "UPR_FAILOVERLOG"
+	CommandNames[UPR_STREAMREQ] = "UPR_STREAMREQ"
+	CommandNames[UPR_STREAMEND] = "UPR_STREAMEND"
+	CommandNames[UPR_SNAPSHOT] = "UPR_SNAPSHOT"
+	CommandNames[UPR_MUTATION] = "UPR_MUTATION"
+	CommandNames[UPR_DELETION] = "UPR_DELETION"
+	CommandNames[UPR_EXPIRATION] = "UPR_EXPIRATION"
+	CommandNames[UPR_FLUSH] = "UPR_FLUSH"
+	CommandNames[UPR_NOOP] = "UPR_NOOP"
+	CommandNames[UPR_BUFFERACK] = "UPR_BUFFERACK"
+	CommandNames[UPR_CONTROL] = "UPR_CONTROL"
+	CommandNames[SUBDOC_GET] = "SUBDOC_GET"
+	CommandNames[SUBDOC_MULTI_LOOKUP] = "SUBDOC_MULTI_LOOKUP"
+
+	StatusNames = make(map[Status]string)
+	StatusNames[SUCCESS] = "SUCCESS"
+	StatusNames[KEY_ENOENT] = "KEY_ENOENT"
+	StatusNames[KEY_EEXISTS] = "KEY_EEXISTS"
+	StatusNames[E2BIG] = "E2BIG"
+	StatusNames[EINVAL] = "EINVAL"
+	StatusNames[NOT_STORED] = "NOT_STORED"
+	StatusNames[DELTA_BADVAL] = "DELTA_BADVAL"
+	StatusNames[NOT_MY_VBUCKET] = "NOT_MY_VBUCKET"
+	StatusNames[NO_BUCKET] = "NO_BUCKET"
+	StatusNames[AUTH_STALE] = "AUTH_STALE"
+	StatusNames[AUTH_ERROR] = "AUTH_ERROR"
+	StatusNames[AUTH_CONTINUE] = "AUTH_CONTINUE"
+	StatusNames[ERANGE] = "ERANGE"
+	StatusNames[ROLLBACK] = "ROLLBACK"
+	StatusNames[EACCESS] = "EACCESS"
+	StatusNames[NOT_INITIALIZED] = "NOT_INITIALIZED"
+	StatusNames[UNKNOWN_COMMAND] = "UNKNOWN_COMMAND"
+	StatusNames[ENOMEM] = "ENOMEM"
+	StatusNames[NOT_SUPPORTED] = "NOT_SUPPORTED"
+	StatusNames[EINTERNAL] = "EINTERNAL"
+	StatusNames[EBUSY] = "EBUSY"
+	StatusNames[TMPFAIL] = "TMPFAIL"
+	StatusNames[SUBDOC_PATH_NOT_FOUND] = "SUBDOC_PATH_NOT_FOUND"
+	StatusNames[SUBDOC_BAD_MULTI] = "SUBDOC_BAD_MULTI"
+
+}
+
+// String an op code.
+func (o CommandCode) String() (rv string) {
+	rv = CommandNames[o]
+	if rv == "" {
+		rv = fmt.Sprintf("0x%02x", int(o))
+	}
+	return rv
+}
+
+// String an op code.
+func (s Status) String() (rv string) {
+	rv = StatusNames[s]
+	if rv == "" {
+		rv = fmt.Sprintf("0x%02x", int(s))
+	}
+	return rv
+}
+
+// IsQuiet will return true if a command is a "quiet" command.
+func (o CommandCode) IsQuiet() bool {
+	switch o {
+	case GETQ,
+		GETKQ,
+		SETQ,
+		ADDQ,
+		REPLACEQ,
+		DELETEQ,
+		INCREMENTQ,
+		DECREMENTQ,
+		QUITQ,
+		FLUSHQ,
+		APPENDQ,
+		PREPENDQ,
+		RSETQ,
+		RAPPENDQ,
+		RPREPENDQ,
+		RDELETEQ,
+		RINCRQ,
+		RDECRQ:
+		return true
+	}
+	return false
+}
diff --git a/vendor/github.com/couchbase/gomemcached/mc_req.go b/vendor/github.com/couchbase/gomemcached/mc_req.go
new file mode 100644
index 0000000000..3ff67ab9a7
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/mc_req.go
@@ -0,0 +1,197 @@
+package gomemcached
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+// The maximum reasonable body length to expect.
+// Anything larger than this will result in an error.
+// The current limit, 20MB, is the size limit supported by ep-engine.
+var MaxBodyLen = int(20 * 1024 * 1024)
+
+// MCRequest is memcached Request
+type MCRequest struct {
+	// The command being issued
+	Opcode CommandCode
+	// The CAS (if applicable, or 0)
+	Cas uint64
+	// An opaque value to be returned with this request
+	Opaque uint32
+	// The vbucket to which this command belongs
+	VBucket uint16
+	// Command extras, key, and body
+	Extras, Key, Body, ExtMeta []byte
+	// Datatype identifier
+	DataType uint8
+}
+
+// Size gives the number of bytes this request requires.
+func (req *MCRequest) Size() int {
+	return HDR_LEN + len(req.Extras) + len(req.Key) + len(req.Body) + len(req.ExtMeta)
+}
+
+// A debugging string representation of this request
+func (req MCRequest) String() string {
+	return fmt.Sprintf("{MCRequest opcode=%s, bodylen=%d, key='%s'}",
+		req.Opcode, len(req.Body), req.Key)
+}
+
+func (req *MCRequest) fillHeaderBytes(data []byte) int {
+
+	pos := 0
+	data[pos] = REQ_MAGIC
+	pos++
+	data[pos] = byte(req.Opcode)
+	pos++
+	binary.BigEndian.PutUint16(data[pos:pos+2],
+		uint16(len(req.Key)))
+	pos += 2
+
+	// 4
+	data[pos] = byte(len(req.Extras))
+	pos++
+	// Data type
+	if req.DataType != 0 {
+		data[pos] = byte(req.DataType)
+	}
+	pos++
+	binary.BigEndian.PutUint16(data[pos:pos+2], req.VBucket)
+	pos += 2
+
+	// 8
+	binary.BigEndian.PutUint32(data[pos:pos+4],
+		uint32(len(req.Body)+len(req.Key)+len(req.Extras)+len(req.ExtMeta)))
+	pos += 4
+
+	// 12
+	binary.BigEndian.PutUint32(data[pos:pos+4], req.Opaque)
+	pos += 4
+
+	// 16
+	if req.Cas != 0 {
+		binary.BigEndian.PutUint64(data[pos:pos+8], req.Cas)
+	}
+	pos += 8
+
+	if len(req.Extras) > 0 {
+		copy(data[pos:pos+len(req.Extras)], req.Extras)
+		pos += len(req.Extras)
+	}
+
+	if len(req.Key) > 0 {
+		copy(data[pos:pos+len(req.Key)], req.Key)
+		pos += len(req.Key)
+	}
+
+	return pos
+}
+
+// HeaderBytes will return the wire representation of the request header
+// (with the extras and key).
+func (req *MCRequest) HeaderBytes() []byte {
+	data := make([]byte, HDR_LEN+len(req.Extras)+len(req.Key))
+
+	req.fillHeaderBytes(data)
+
+	return data
+}
+
+// Bytes will return the wire representation of this request.
+func (req *MCRequest) Bytes() []byte {
+	data := make([]byte, req.Size())
+
+	pos := req.fillHeaderBytes(data)
+
+	if len(req.Body) > 0 {
+		copy(data[pos:pos+len(req.Body)], req.Body)
+	}
+
+	if len(req.ExtMeta) > 0 {
+		copy(data[pos+len(req.Body):pos+len(req.Body)+len(req.ExtMeta)], req.ExtMeta)
+	}
+
+	return data
+}
+
+// Transmit will send this request message across a writer.
+func (req *MCRequest) Transmit(w io.Writer) (n int, err error) {
+	if len(req.Body) < 128 {
+		n, err = w.Write(req.Bytes())
+	} else {
+		n, err = w.Write(req.HeaderBytes())
+		if err == nil {
+			m := 0
+			m, err = w.Write(req.Body)
+			n += m
+		}
+	}
+	return
+}
+
+// Receive will fill this MCRequest with the data from a reader.
+func (req *MCRequest) Receive(r io.Reader, hdrBytes []byte) (int, error) {
+	if len(hdrBytes) < HDR_LEN {
+		hdrBytes = []byte{
+			0, 0, 0, 0, 0, 0, 0, 0,
+			0, 0, 0, 0, 0, 0, 0, 0,
+			0, 0, 0, 0, 0, 0, 0, 0}
+	}
+	n, err := io.ReadFull(r, hdrBytes)
+	if err != nil {
+		return n, err
+	}
+
+	if hdrBytes[0] != RES_MAGIC && hdrBytes[0] != REQ_MAGIC {
+		return n, fmt.Errorf("bad magic: 0x%02x", hdrBytes[0])
+	}
+
+	klen := int(binary.BigEndian.Uint16(hdrBytes[2:]))
+	elen := int(hdrBytes[4])
+	// Data type at 5
+	req.DataType = uint8(hdrBytes[5])
+
+	req.Opcode = CommandCode(hdrBytes[1])
+	// Vbucket at 6:7
+	req.VBucket = binary.BigEndian.Uint16(hdrBytes[6:])
+	totalBodyLen := int(binary.BigEndian.Uint32(hdrBytes[8:]))
+
+	req.Opaque = binary.BigEndian.Uint32(hdrBytes[12:])
+	req.Cas = binary.BigEndian.Uint64(hdrBytes[16:])
+
+	if totalBodyLen > 0 {
+		buf := make([]byte, totalBodyLen)
+		m, err := io.ReadFull(r, buf)
+		n += m
+		if err == nil {
+			if req.Opcode >= TAP_MUTATION &&
+				req.Opcode <= TAP_CHECKPOINT_END &&
+				len(buf) > 1 {
+				// In these commands there is "engine private"
+				// data at the end of the extras.  The first 2
+				// bytes of extra data give its length.
+				elen += int(binary.BigEndian.Uint16(buf))
+			}
+
+			req.Extras = buf[0:elen]
+			req.Key = buf[elen : klen+elen]
+
+			// get the length of extended metadata
+			extMetaLen := 0
+			if elen > 29 {
+				extMetaLen = int(binary.BigEndian.Uint16(req.Extras[28:30]))
+			}
+
+			bodyLen := totalBodyLen - klen - elen - extMetaLen
+			if bodyLen > MaxBodyLen {
+				return n, fmt.Errorf("%d is too big (max %d)",
+					bodyLen, MaxBodyLen)
+			}
+
+			req.Body = buf[klen+elen : klen+elen+bodyLen]
+			req.ExtMeta = buf[klen+elen+bodyLen:]
+		}
+	}
+	return n, err
+}
diff --git a/vendor/github.com/couchbase/gomemcached/mc_res.go b/vendor/github.com/couchbase/gomemcached/mc_res.go
new file mode 100644
index 0000000000..2b4cfe1349
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/mc_res.go
@@ -0,0 +1,267 @@
+package gomemcached
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"sync"
+)
+
+// MCResponse is memcached response
+type MCResponse struct {
+	// The command opcode of the command that sent the request
+	Opcode CommandCode
+	// The status of the response
+	Status Status
+	// The opaque sent in the request
+	Opaque uint32
+	// The CAS identifier (if applicable)
+	Cas uint64
+	// Extras, key, and body for this response
+	Extras, Key, Body []byte
+	// If true, this represents a fatal condition and we should hang up
+	Fatal bool
+	// Datatype identifier
+	DataType uint8
+}
+
+// A debugging string representation of this response
+func (res MCResponse) String() string {
+	return fmt.Sprintf("{MCResponse status=%v keylen=%d, extralen=%d, bodylen=%d}",
+		res.Status, len(res.Key), len(res.Extras), len(res.Body))
+}
+
+// Response as an error.
+func (res *MCResponse) Error() string {
+	return fmt.Sprintf("MCResponse status=%v, opcode=%v, opaque=%v, msg: %s",
+		res.Status, res.Opcode, res.Opaque, string(res.Body))
+}
+
+func errStatus(e error) Status {
+	status := Status(0xffff)
+	if res, ok := e.(*MCResponse); ok {
+		status = res.Status
+	}
+	return status
+}
+
+// IsNotFound is true if this error represents a "not found" response.
+func IsNotFound(e error) bool {
+	return errStatus(e) == KEY_ENOENT
+}
+
+// IsFatal is false if this error isn't believed to be fatal to a connection.
+func IsFatal(e error) bool {
+	if e == nil {
+		return false
+	}
+	_, ok := isFatal[errStatus(e)]
+	if ok {
+		return true
+	}
+	return false
+}
+
+// Size is number of bytes this response consumes on the wire.
+func (res *MCResponse) Size() int {
+	return HDR_LEN + len(res.Extras) + len(res.Key) + len(res.Body)
+}
+
+func (res *MCResponse) fillHeaderBytes(data []byte) int {
+	pos := 0
+	data[pos] = RES_MAGIC
+	pos++
+	data[pos] = byte(res.Opcode)
+	pos++
+	binary.BigEndian.PutUint16(data[pos:pos+2],
+		uint16(len(res.Key)))
+	pos += 2
+
+	// 4
+	data[pos] = byte(len(res.Extras))
+	pos++
+	// Data type
+	if res.DataType != 0 {
+		data[pos] = byte(res.DataType)
+	} else {
+		data[pos] = 0
+	}
+	pos++
+	binary.BigEndian.PutUint16(data[pos:pos+2], uint16(res.Status))
+	pos += 2
+
+	// 8
+	binary.BigEndian.PutUint32(data[pos:pos+4],
+		uint32(len(res.Body)+len(res.Key)+len(res.Extras)))
+	pos += 4
+
+	// 12
+	binary.BigEndian.PutUint32(data[pos:pos+4], res.Opaque)
+	pos += 4
+
+	// 16
+	binary.BigEndian.PutUint64(data[pos:pos+8], res.Cas)
+	pos += 8
+
+	if len(res.Extras) > 0 {
+		copy(data[pos:pos+len(res.Extras)], res.Extras)
+		pos += len(res.Extras)
+	}
+
+	if len(res.Key) > 0 {
+		copy(data[pos:pos+len(res.Key)], res.Key)
+		pos += len(res.Key)
+	}
+
+	return pos
+}
+
+// HeaderBytes will get just the header bytes for this response.
+func (res *MCResponse) HeaderBytes() []byte {
+	data := make([]byte, HDR_LEN+len(res.Extras)+len(res.Key))
+
+	res.fillHeaderBytes(data)
+
+	return data
+}
+
+// Bytes will return the actual bytes transmitted for this response.
+func (res *MCResponse) Bytes() []byte {
+	data := make([]byte, res.Size())
+
+	pos := res.fillHeaderBytes(data)
+
+	copy(data[pos:pos+len(res.Body)], res.Body)
+
+	return data
+}
+
+// Transmit will send this response message across a writer.
+func (res *MCResponse) Transmit(w io.Writer) (n int, err error) {
+	if len(res.Body) < 128 {
+		n, err = w.Write(res.Bytes())
+	} else {
+		n, err = w.Write(res.HeaderBytes())
+		if err == nil {
+			m := 0
+			m, err = w.Write(res.Body)
+			m += n
+		}
+	}
+	return
+}
+
+// Receive will fill this MCResponse with the data from this reader.
+func (res *MCResponse) Receive(r io.Reader, hdrBytes []byte) (n int, err error) {
+	if len(hdrBytes) < HDR_LEN {
+		hdrBytes = []byte{
+			0, 0, 0, 0, 0, 0, 0, 0,
+			0, 0, 0, 0, 0, 0, 0, 0,
+			0, 0, 0, 0, 0, 0, 0, 0}
+	}
+	n, err = io.ReadFull(r, hdrBytes)
+	if err != nil {
+		return n, err
+	}
+
+	if hdrBytes[0] != RES_MAGIC && hdrBytes[0] != REQ_MAGIC {
+		return n, fmt.Errorf("bad magic: 0x%02x", hdrBytes[0])
+	}
+
+	klen := int(binary.BigEndian.Uint16(hdrBytes[2:4]))
+	elen := int(hdrBytes[4])
+
+	res.Opcode = CommandCode(hdrBytes[1])
+	res.DataType = uint8(hdrBytes[5])
+	res.Status = Status(binary.BigEndian.Uint16(hdrBytes[6:8]))
+	res.Opaque = binary.BigEndian.Uint32(hdrBytes[12:16])
+	res.Cas = binary.BigEndian.Uint64(hdrBytes[16:24])
+
+	bodyLen := int(binary.BigEndian.Uint32(hdrBytes[8:12])) - (klen + elen)
+
+	//defer function to debug the panic seen with MB-15557
+	defer func() {
+		if e := recover(); e != nil {
+			err = fmt.Errorf(`Panic in Receive. Response %v \n
+                        key len %v extra len %v bodylen %v`, res, klen, elen, bodyLen)
+		}
+	}()
+
+	buf := make([]byte, klen+elen+bodyLen)
+	m, err := io.ReadFull(r, buf)
+	if err == nil {
+		res.Extras = buf[0:elen]
+		res.Key = buf[elen : klen+elen]
+		res.Body = buf[klen+elen:]
+	}
+
+	return n + m, err
+}
+
+type MCResponsePool struct {
+	pool *sync.Pool
+}
+
+func NewMCResponsePool() *MCResponsePool {
+	rv := &MCResponsePool{
+		pool: &sync.Pool{
+			New: func() interface{} {
+				return &MCResponse{}
+			},
+		},
+	}
+
+	return rv
+}
+
+func (this *MCResponsePool) Get() *MCResponse {
+	return this.pool.Get().(*MCResponse)
+}
+
+func (this *MCResponsePool) Put(r *MCResponse) {
+	if r == nil {
+		return
+	}
+
+	r.Extras = nil
+	r.Key = nil
+	r.Body = nil
+	r.Fatal = false
+
+	this.pool.Put(r)
+}
+
+type StringMCResponsePool struct {
+	pool *sync.Pool
+	size int
+}
+
+func NewStringMCResponsePool(size int) *StringMCResponsePool {
+	rv := &StringMCResponsePool{
+		pool: &sync.Pool{
+			New: func() interface{} {
+				return make(map[string]*MCResponse, size)
+			},
+		},
+		size: size,
+	}
+
+	return rv
+}
+
+func (this *StringMCResponsePool) Get() map[string]*MCResponse {
+	return this.pool.Get().(map[string]*MCResponse)
+}
+
+func (this *StringMCResponsePool) Put(m map[string]*MCResponse) {
+	if m == nil || len(m) > 2*this.size {
+		return
+	}
+
+	for k := range m {
+		m[k] = nil
+		delete(m, k)
+	}
+
+	this.pool.Put(m)
+}
diff --git a/vendor/github.com/couchbase/gomemcached/tap.go b/vendor/github.com/couchbase/gomemcached/tap.go
new file mode 100644
index 0000000000..e48623281b
--- /dev/null
+++ b/vendor/github.com/couchbase/gomemcached/tap.go
@@ -0,0 +1,168 @@
+package gomemcached
+
+import (
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"strings"
+)
+
+type TapConnectFlag uint32
+
+// Tap connect option flags
+const (
+	BACKFILL           = TapConnectFlag(0x01)
+	DUMP               = TapConnectFlag(0x02)
+	LIST_VBUCKETS      = TapConnectFlag(0x04)
+	TAKEOVER_VBUCKETS  = TapConnectFlag(0x08)
+	SUPPORT_ACK        = TapConnectFlag(0x10)
+	REQUEST_KEYS_ONLY  = TapConnectFlag(0x20)
+	CHECKPOINT         = TapConnectFlag(0x40)
+	REGISTERED_CLIENT  = TapConnectFlag(0x80)
+	FIX_FLAG_BYTEORDER = TapConnectFlag(0x100)
+)
+
+// Tap opaque event subtypes
+const (
+	TAP_OPAQUE_ENABLE_AUTO_NACK       = 0
+	TAP_OPAQUE_INITIAL_VBUCKET_STREAM = 1
+	TAP_OPAQUE_ENABLE_CHECKPOINT_SYNC = 2
+	TAP_OPAQUE_CLOSE_TAP_STREAM       = 7
+	TAP_OPAQUE_CLOSE_BACKFILL         = 8
+)
+
+// Tap item flags
+const (
+	TAP_ACK                     = 1
+	TAP_NO_VALUE                = 2
+	TAP_FLAG_NETWORK_BYTE_ORDER = 4
+)
+
+// TapConnectFlagNames for TapConnectFlag
+var TapConnectFlagNames = map[TapConnectFlag]string{
+	BACKFILL:           "BACKFILL",
+	DUMP:               "DUMP",
+	LIST_VBUCKETS:      "LIST_VBUCKETS",
+	TAKEOVER_VBUCKETS:  "TAKEOVER_VBUCKETS",
+	SUPPORT_ACK:        "SUPPORT_ACK",
+	REQUEST_KEYS_ONLY:  "REQUEST_KEYS_ONLY",
+	CHECKPOINT:         "CHECKPOINT",
+	REGISTERED_CLIENT:  "REGISTERED_CLIENT",
+	FIX_FLAG_BYTEORDER: "FIX_FLAG_BYTEORDER",
+}
+
+// TapItemParser is a function to parse a single tap extra.
+type TapItemParser func(io.Reader) (interface{}, error)
+
+// TapParseUint64 is a function to parse a single tap uint64.
+func TapParseUint64(r io.Reader) (interface{}, error) {
+	var rv uint64
+	err := binary.Read(r, binary.BigEndian, &rv)
+	return rv, err
+}
+
+// TapParseUint16 is a function to parse a single tap uint16.
+func TapParseUint16(r io.Reader) (interface{}, error) {
+	var rv uint16
+	err := binary.Read(r, binary.BigEndian, &rv)
+	return rv, err
+}
+
+// TapParseBool is a function to parse a single tap boolean.
+func TapParseBool(r io.Reader) (interface{}, error) {
+	return true, nil
+}
+
+// TapParseVBList parses a list of vBucket numbers as []uint16.
+func TapParseVBList(r io.Reader) (interface{}, error) {
+	num, err := TapParseUint16(r)
+	if err != nil {
+		return nil, err
+	}
+	n := int(num.(uint16))
+
+	rv := make([]uint16, n)
+	for i := 0; i < n; i++ {
+		x, err := TapParseUint16(r)
+		if err != nil {
+			return nil, err
+		}
+		rv[i] = x.(uint16)
+	}
+
+	return rv, err
+}
+
+// TapFlagParsers parser functions for TAP fields.
+var TapFlagParsers = map[TapConnectFlag]TapItemParser{
+	BACKFILL:      TapParseUint64,
+	LIST_VBUCKETS: TapParseVBList,
+}
+
+// SplitFlags will split the ORed flags into the individual bit flags.
+func (f TapConnectFlag) SplitFlags() []TapConnectFlag {
+	rv := []TapConnectFlag{}
+	for i := uint32(1); f != 0; i = i << 1 {
+		if uint32(f)&i == i {
+			rv = append(rv, TapConnectFlag(i))
+		}
+		f = TapConnectFlag(uint32(f) & (^i))
+	}
+	return rv
+}
+
+func (f TapConnectFlag) String() string {
+	parts := []string{}
+	for _, x := range f.SplitFlags() {
+		p := TapConnectFlagNames[x]
+		if p == "" {
+			p = fmt.Sprintf("0x%x", int(x))
+		}
+		parts = append(parts, p)
+	}
+	return strings.Join(parts, "|")
+}
+
+type TapConnect struct {
+	Flags         map[TapConnectFlag]interface{}
+	RemainingBody []byte
+	Name          string
+}
+
+// ParseTapCommands parse the tap request into the interesting bits we may
+// need to do something with.
+func (req *MCRequest) ParseTapCommands() (TapConnect, error) {
+	rv := TapConnect{
+		Flags: map[TapConnectFlag]interface{}{},
+		Name:  string(req.Key),
+	}
+
+	if len(req.Extras) < 4 {
+		return rv, fmt.Errorf("not enough extra bytes: %x", req.Extras)
+	}
+
+	flags := TapConnectFlag(binary.BigEndian.Uint32(req.Extras))
+
+	r := bytes.NewReader(req.Body)
+
+	for _, f := range flags.SplitFlags() {
+		fun := TapFlagParsers[f]
+		if fun == nil {
+			fun = TapParseBool
+		}
+
+		val, err := fun(r)
+		if err != nil {
+			return rv, err
+		}
+
+		rv.Flags[f] = val
+	}
+
+	var err error
+	rv.RemainingBody, err = ioutil.ReadAll(r)
+
+	return rv, err
+}
diff --git a/vendor/github.com/couchbase/goutils/LICENSE.md b/vendor/github.com/couchbase/goutils/LICENSE.md
new file mode 100644
index 0000000000..a572e246e6
--- /dev/null
+++ b/vendor/github.com/couchbase/goutils/LICENSE.md
@@ -0,0 +1,47 @@
+COUCHBASE INC. COMMUNITY EDITION LICENSE AGREEMENT
+
+IMPORTANT-READ CAREFULLY: BY CLICKING THE "I ACCEPT" BOX OR INSTALLING,
+DOWNLOADING OR OTHERWISE USING THIS SOFTWARE AND ANY ASSOCIATED
+DOCUMENTATION, YOU, ON BEHALF OF YOURSELF OR AS AN AUTHORIZED
+REPRESENTATIVE ON BEHALF OF AN ENTITY ("LICENSEE") AGREE TO ALL THE
+TERMS OF THIS COMMUNITY EDITION LICENSE AGREEMENT (THE "AGREEMENT")
+REGARDING YOUR USE OF THE SOFTWARE.  YOU REPRESENT AND WARRANT THAT YOU
+HAVE FULL LEGAL AUTHORITY TO BIND THE LICENSEE TO THIS AGREEMENT. IF YOU
+DO NOT AGREE WITH ALL OF THESE TERMS, DO NOT SELECT THE "I ACCEPT" BOX
+AND DO NOT INSTALL, DOWNLOAD OR OTHERWISE USE THE SOFTWARE. THE
+EFFECTIVE DATE OF THIS AGREEMENT IS THE DATE ON WHICH YOU CLICK "I
+ACCEPT" OR OTHERWISE INSTALL, DOWNLOAD OR USE THE SOFTWARE.
+
+1. License Grant. Couchbase Inc. hereby grants Licensee, free of charge,
+the non-exclusive right to use, copy, merge, publish, distribute,
+sublicense, and/or sell copies of the Software, and to permit persons to
+whom the Software is furnished to do so, subject to Licensee including
+the following copyright notice in all copies or substantial portions of
+the Software:
+
+Couchbase (r) http://www.Couchbase.com Copyright 2016 Couchbase, Inc.
+
+As used in this Agreement, "Software" means the object code version of
+the applicable elastic data management server software provided by
+Couchbase Inc.
+
+2. Restrictions. Licensee will not reverse engineer, disassemble, or
+decompile the Software (except to the extent such restrictions are
+prohibited by law).
+
+3. Support. Couchbase, Inc. will provide Licensee with access to, and
+use of, the Couchbase, Inc. support forum available at the following
+URL: http://www.couchbase.org/forums/. Couchbase, Inc. may, at its
+discretion, modify, suspend or terminate support at any time upon notice
+to Licensee.
+
+4. Warranty Disclaimer and Limitation of Liability. THE SOFTWARE IS
+PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+COUCHBASE INC. OR THE AUTHORS OR COPYRIGHT HOLDERS IN THE SOFTWARE BE
+LIABLE FOR ANY CLAIM, DAMAGES (IINCLUDING, WITHOUT LIMITATION, DIRECT,
+INDIRECT OR CONSEQUENTIAL DAMAGES) OR OTHER LIABILITY, WHETHER IN AN
+ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/couchbase/goutils/logging/logger.go b/vendor/github.com/couchbase/goutils/logging/logger.go
new file mode 100644
index 0000000000..b9948f9b2e
--- /dev/null
+++ b/vendor/github.com/couchbase/goutils/logging/logger.go
@@ -0,0 +1,481 @@
+//  Copyright (c) 2016 Couchbase, Inc.
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+//  except in compliance with the License. You may obtain a copy of the License at
+//    http://www.apache.org/licenses/LICENSE-2.0
+//  Unless required by applicable law or agreed to in writing, software distributed under the
+//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+//  either express or implied. See the License for the specific language governing permissions
+//  and limitations under the License.
+
+package logging
+
+import (
+	"os"
+	"runtime"
+	"strings"
+	"sync"
+)
+
+type Level int
+
+const (
+	NONE    = Level(iota) // Disable all logging
+	FATAL                 // System is in severe error state and has to abort
+	SEVERE                // System is in severe error state and cannot recover reliably
+	ERROR                 // System is in error state but can recover and continue reliably
+	WARN                  // System approaching error state, or is in a correct but undesirable state
+	INFO                  // System-level events and status, in correct states
+	REQUEST               // Request-level events, with request-specific rlevel
+	TRACE                 // Trace detailed system execution, e.g. function entry / exit
+	DEBUG                 // Debug
+)
+
+type LogEntryFormatter int
+
+const (
+	TEXTFORMATTER = LogEntryFormatter(iota)
+	JSONFORMATTER
+	KVFORMATTER
+)
+
+func (level Level) String() string {
+	return _LEVEL_NAMES[level]
+}
+
+var _LEVEL_NAMES = []string{
+	DEBUG:   "DEBUG",
+	TRACE:   "TRACE",
+	REQUEST: "REQUEST",
+	INFO:    "INFO",
+	WARN:    "WARN",
+	ERROR:   "ERROR",
+	SEVERE:  "SEVERE",
+	FATAL:   "FATAL",
+	NONE:    "NONE",
+}
+
+var _LEVEL_MAP = map[string]Level{
+	"debug":   DEBUG,
+	"trace":   TRACE,
+	"request": REQUEST,
+	"info":    INFO,
+	"warn":    WARN,
+	"error":   ERROR,
+	"severe":  SEVERE,
+	"fatal":   FATAL,
+	"none":    NONE,
+}
+
+func ParseLevel(name string) (level Level, ok bool) {
+	level, ok = _LEVEL_MAP[strings.ToLower(name)]
+	return
+}
+
+/*
+
+Pair supports logging of key-value pairs.  Keys beginning with _ are
+reserved for the logger, e.g. _time, _level, _msg, and _rlevel. The
+Pair APIs are designed to avoid heap allocation and garbage
+collection.
+
+*/
+type Pairs []Pair
+type Pair struct {
+	Name  string
+	Value interface{}
+}
+
+/*
+
+Map allows key-value pairs to be specified using map literals or data
+structures. For example:
+
+Errorm(msg, Map{...})
+
+Map incurs heap allocation and garbage collection, so the Pair APIs
+should be preferred.
+
+*/
+type Map map[string]interface{}
+
+// Logger provides a common interface for logging libraries
+type Logger interface {
+	/*
+		These APIs write all the given pairs in addition to standard logger keys.
+	*/
+	Logp(level Level, msg string, kv ...Pair)
+
+	Debugp(msg string, kv ...Pair)
+
+	Tracep(msg string, kv ...Pair)
+
+	Requestp(rlevel Level, msg string, kv ...Pair)
+
+	Infop(msg string, kv ...Pair)
+
+	Warnp(msg string, kv ...Pair)
+
+	Errorp(msg string, kv ...Pair)
+
+	Severep(msg string, kv ...Pair)
+
+	Fatalp(msg string, kv ...Pair)
+
+	/*
+		These APIs write the fields in the given kv Map in addition to standard logger keys.
+	*/
+	Logm(level Level, msg string, kv Map)
+
+	Debugm(msg string, kv Map)
+
+	Tracem(msg string, kv Map)
+
+	Requestm(rlevel Level, msg string, kv Map)
+
+	Infom(msg string, kv Map)
+
+	Warnm(msg string, kv Map)
+
+	Errorm(msg string, kv Map)
+
+	Severem(msg string, kv Map)
+
+	Fatalm(msg string, kv Map)
+
+	/*
+
+		These APIs only write _msg, _time, _level, and other logger keys. If
+		the msg contains other fields, use the Pair or Map APIs instead.
+
+	*/
+	Logf(level Level, fmt string, args ...interface{})
+
+	Debugf(fmt string, args ...interface{})
+
+	Tracef(fmt string, args ...interface{})
+
+	Requestf(rlevel Level, fmt string, args ...interface{})
+
+	Infof(fmt string, args ...interface{})
+
+	Warnf(fmt string, args ...interface{})
+
+	Errorf(fmt string, args ...interface{})
+
+	Severef(fmt string, args ...interface{})
+
+	Fatalf(fmt string, args ...interface{})
+
+	/*
+		These APIs control the logging level
+	*/
+
+	SetLevel(Level) // Set the logging level
+
+	Level() Level // Get the current logging level
+}
+
+var logger Logger = nil
+var curLevel Level = DEBUG // initially set to never skip
+
+var loggerMutex sync.RWMutex
+
+// All the methods below first acquire the mutex (mostly in exclusive mode)
+// and only then check if logging at the current level is enabled.
+// This introduces a fair bottleneck for those log entries that should be
+// skipped (the majority, at INFO or below levels)
+// We try to predict here if we should lock the mutex at all by caching
+// the current log level: while dynamically changing logger, there might
+// be the odd entry skipped as the new level is cached.
+// Since we seem to never change the logger, this is not an issue.
+func skipLogging(level Level) bool {
+	if logger == nil {
+		return true
+	}
+	return level > curLevel
+}
+
+func SetLogger(newLogger Logger) {
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger = newLogger
+	if logger == nil {
+		curLevel = NONE
+	} else {
+		curLevel = newLogger.Level()
+	}
+}
+
+func Logp(level Level, msg string, kv ...Pair) {
+	if skipLogging(level) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Logp(level, msg, kv...)
+}
+
+func Debugp(msg string, kv ...Pair) {
+	if skipLogging(DEBUG) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Debugp(msg, kv...)
+}
+
+func Tracep(msg string, kv ...Pair) {
+	if skipLogging(TRACE) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Tracep(msg, kv...)
+}
+
+func Requestp(rlevel Level, msg string, kv ...Pair) {
+	if skipLogging(REQUEST) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Requestp(rlevel, msg, kv...)
+}
+
+func Infop(msg string, kv ...Pair) {
+	if skipLogging(INFO) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Infop(msg, kv...)
+}
+
+func Warnp(msg string, kv ...Pair) {
+	if skipLogging(WARN) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Warnp(msg, kv...)
+}
+
+func Errorp(msg string, kv ...Pair) {
+	if skipLogging(ERROR) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Errorp(msg, kv...)
+}
+
+func Severep(msg string, kv ...Pair) {
+	if skipLogging(SEVERE) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Severep(msg, kv...)
+}
+
+func Fatalp(msg string, kv ...Pair) {
+	if skipLogging(FATAL) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Fatalp(msg, kv...)
+}
+
+func Logm(level Level, msg string, kv Map) {
+	if skipLogging(level) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Logm(level, msg, kv)
+}
+
+func Debugm(msg string, kv Map) {
+	if skipLogging(DEBUG) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Debugm(msg, kv)
+}
+
+func Tracem(msg string, kv Map) {
+	if skipLogging(TRACE) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Tracem(msg, kv)
+}
+
+func Requestm(rlevel Level, msg string, kv Map) {
+	if skipLogging(REQUEST) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Requestm(rlevel, msg, kv)
+}
+
+func Infom(msg string, kv Map) {
+	if skipLogging(INFO) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Infom(msg, kv)
+}
+
+func Warnm(msg string, kv Map) {
+	if skipLogging(WARN) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Warnm(msg, kv)
+}
+
+func Errorm(msg string, kv Map) {
+	if skipLogging(ERROR) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Errorm(msg, kv)
+}
+
+func Severem(msg string, kv Map) {
+	if skipLogging(SEVERE) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Severem(msg, kv)
+}
+
+func Fatalm(msg string, kv Map) {
+	if skipLogging(FATAL) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Fatalm(msg, kv)
+}
+
+func Logf(level Level, fmt string, args ...interface{}) {
+	if skipLogging(level) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Logf(level, fmt, args...)
+}
+
+func Debugf(fmt string, args ...interface{}) {
+	if skipLogging(DEBUG) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Debugf(fmt, args...)
+}
+
+func Tracef(fmt string, args ...interface{}) {
+	if skipLogging(TRACE) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Tracef(fmt, args...)
+}
+
+func Requestf(rlevel Level, fmt string, args ...interface{}) {
+	if skipLogging(REQUEST) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Requestf(rlevel, fmt, args...)
+}
+
+func Infof(fmt string, args ...interface{}) {
+	if skipLogging(INFO) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Infof(fmt, args...)
+}
+
+func Warnf(fmt string, args ...interface{}) {
+	if skipLogging(WARN) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Warnf(fmt, args...)
+}
+
+func Errorf(fmt string, args ...interface{}) {
+	if skipLogging(ERROR) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Errorf(fmt, args...)
+}
+
+func Severef(fmt string, args ...interface{}) {
+	if skipLogging(SEVERE) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Severef(fmt, args...)
+}
+
+func Fatalf(fmt string, args ...interface{}) {
+	if skipLogging(FATAL) {
+		return
+	}
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Fatalf(fmt, args...)
+}
+
+func SetLevel(level Level) {
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.SetLevel(level)
+	curLevel = level
+}
+
+func LogLevel() Level {
+	loggerMutex.RLock()
+	defer loggerMutex.RUnlock()
+	return logger.Level()
+}
+
+func Stackf(level Level, fmt string, args ...interface{}) {
+	if skipLogging(level) {
+		return
+	}
+	buf := make([]byte, 1<<16)
+	n := runtime.Stack(buf, false)
+	s := string(buf[0:n])
+	loggerMutex.Lock()
+	defer loggerMutex.Unlock()
+	logger.Logf(level, fmt, args...)
+	logger.Logf(level, s)
+}
+
+func init() {
+	logger = NewLogger(os.Stderr, INFO, TEXTFORMATTER)
+	SetLogger(logger)
+}
diff --git a/vendor/github.com/couchbase/goutils/logging/logger_golog.go b/vendor/github.com/couchbase/goutils/logging/logger_golog.go
new file mode 100644
index 0000000000..eec432a513
--- /dev/null
+++ b/vendor/github.com/couchbase/goutils/logging/logger_golog.go
@@ -0,0 +1,318 @@
+//  Copyright (c) 2016 Couchbase, Inc.
+//  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file
+//  except in compliance with the License. You may obtain a copy of the License at
+//    http://www.apache.org/licenses/LICENSE-2.0
+//  Unless required by applicable law or agreed to in writing, software distributed under the
+//  License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
+//  either express or implied. See the License for the specific language governing permissions
+//  and limitations under the License.
+
+package logging
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"log"
+	"time"
+)
+
+type goLogger struct {
+	logger         *log.Logger
+	level          Level
+	entryFormatter formatter
+}
+
+const (
+	_LEVEL  = "_level"
+	_MSG    = "_msg"
+	_TIME   = "_time"
+	_RLEVEL = "_rlevel"
+)
+
+func NewLogger(out io.Writer, lvl Level, fmtLogging LogEntryFormatter) *goLogger {
+	logger := &goLogger{
+		logger: log.New(out, "", 0),
+		level:  lvl,
+	}
+	if fmtLogging == JSONFORMATTER {
+		logger.entryFormatter = &jsonFormatter{}
+	} else if fmtLogging == KVFORMATTER {
+		logger.entryFormatter = &keyvalueFormatter{}
+	} else {
+		logger.entryFormatter = &textFormatter{}
+	}
+	return logger
+}
+
+func (gl *goLogger) Logp(level Level, msg string, kv ...Pair) {
+	if gl.logger == nil {
+		return
+	}
+	if level <= gl.level {
+		e := newLogEntry(msg, level)
+		copyPairs(e, kv)
+		gl.log(e)
+	}
+}
+
+func (gl *goLogger) Debugp(msg string, kv ...Pair) {
+	gl.Logp(DEBUG, msg, kv...)
+}
+
+func (gl *goLogger) Tracep(msg string, kv ...Pair) {
+	gl.Logp(TRACE, msg, kv...)
+}
+
+func (gl *goLogger) Requestp(rlevel Level, msg string, kv ...Pair) {
+	if gl.logger == nil {
+		return
+	}
+	if REQUEST <= gl.level {
+		e := newLogEntry(msg, REQUEST)
+		e.Rlevel = rlevel
+		copyPairs(e, kv)
+		gl.log(e)
+	}
+}
+
+func (gl *goLogger) Infop(msg string, kv ...Pair) {
+	gl.Logp(INFO, msg, kv...)
+}
+
+func (gl *goLogger) Warnp(msg string, kv ...Pair) {
+	gl.Logp(WARN, msg, kv...)
+}
+
+func (gl *goLogger) Errorp(msg string, kv ...Pair) {
+	gl.Logp(ERROR, msg, kv...)
+}
+
+func (gl *goLogger) Severep(msg string, kv ...Pair) {
+	gl.Logp(SEVERE, msg, kv...)
+}
+
+func (gl *goLogger) Fatalp(msg string, kv ...Pair) {
+	gl.Logp(FATAL, msg, kv...)
+}
+
+func (gl *goLogger) Logm(level Level, msg string, kv Map) {
+	if gl.logger == nil {
+		return
+	}
+	if level <= gl.level {
+		e := newLogEntry(msg, level)
+		e.Data = kv
+		gl.log(e)
+	}
+}
+
+func (gl *goLogger) Debugm(msg string, kv Map) {
+	gl.Logm(DEBUG, msg, kv)
+}
+
+func (gl *goLogger) Tracem(msg string, kv Map) {
+	gl.Logm(TRACE, msg, kv)
+}
+
+func (gl *goLogger) Requestm(rlevel Level, msg string, kv Map) {
+	if gl.logger == nil {
+		return
+	}
+	if REQUEST <= gl.level {
+		e := newLogEntry(msg, REQUEST)
+		e.Rlevel = rlevel
+		e.Data = kv
+		gl.log(e)
+	}
+}
+
+func (gl *goLogger) Infom(msg string, kv Map) {
+	gl.Logm(INFO, msg, kv)
+}
+
+func (gl *goLogger) Warnm(msg string, kv Map) {
+	gl.Logm(WARN, msg, kv)
+}
+
+func (gl *goLogger) Errorm(msg string, kv Map) {
+	gl.Logm(ERROR, msg, kv)
+}
+
+func (gl *goLogger) Severem(msg string, kv Map) {
+	gl.Logm(SEVERE, msg, kv)
+}
+
+func (gl *goLogger) Fatalm(msg string, kv Map) {
+	gl.Logm(FATAL, msg, kv)
+}
+
+func (gl *goLogger) Logf(level Level, format string, args ...interface{}) {
+	if gl.logger == nil {
+		return
+	}
+	if level <= gl.level {
+		e := newLogEntry(fmt.Sprintf(format, args...), level)
+		gl.log(e)
+	}
+}
+
+func (gl *goLogger) Debugf(format string, args ...interface{}) {
+	gl.Logf(DEBUG, format, args...)
+}
+
+func (gl *goLogger) Tracef(format string, args ...interface{}) {
+	gl.Logf(TRACE, format, args...)
+}
+
+func (gl *goLogger) Requestf(rlevel Level, format string, args ...interface{}) {
+	if gl.logger == nil {
+		return
+	}
+	if REQUEST <= gl.level {
+		e := newLogEntry(fmt.Sprintf(format, args...), REQUEST)
+		e.Rlevel = rlevel
+		gl.log(e)
+	}
+}
+
+func (gl *goLogger) Infof(format string, args ...interface{}) {
+	gl.Logf(INFO, format, args...)
+}
+
+func (gl *goLogger) Warnf(format string, args ...interface{}) {
+	gl.Logf(WARN, format, args...)
+}
+
+func (gl *goLogger) Errorf(format string, args ...interface{}) {
+	gl.Logf(ERROR, format, args...)
+}
+
+func (gl *goLogger) Severef(format string, args ...interface{}) {
+	gl.Logf(SEVERE, format, args...)
+}
+
+func (gl *goLogger) Fatalf(format string, args ...interface{}) {
+	gl.Logf(FATAL, format, args...)
+}
+
+func (gl *goLogger) Level() Level {
+	return gl.level
+}
+
+func (gl *goLogger) SetLevel(level Level) {
+	gl.level = level
+}
+
+func (gl *goLogger) log(newEntry *logEntry) {
+	s := gl.entryFormatter.format(newEntry)
+	gl.logger.Print(s)
+}
+
+type logEntry struct {
+	Time    string
+	Level   Level
+	Rlevel  Level
+	Message string
+	Data    Map
+}
+
+func newLogEntry(msg string, level Level) *logEntry {
+	return &logEntry{
+		Time:    time.Now().Format("2006-01-02T15:04:05.000-07:00"), // time.RFC3339 with milliseconds
+		Level:   level,
+		Rlevel:  NONE,
+		Message: msg,
+	}
+}
+
+func copyPairs(newEntry *logEntry, pairs []Pair) {
+	newEntry.Data = make(Map, len(pairs))
+	for _, p := range pairs {
+		newEntry.Data[p.Name] = p.Value
+	}
+}
+
+type formatter interface {
+	format(*logEntry) string
+}
+
+type textFormatter struct {
+}
+
+// ex. 2016-02-10T09:15:25.498-08:00 [INFO] This is a message from test in text format
+
+func (*textFormatter) format(newEntry *logEntry) string {
+	b := &bytes.Buffer{}
+	appendValue(b, newEntry.Time)
+	if newEntry.Rlevel != NONE {
+		fmt.Fprintf(b, "[%s,%s] ", newEntry.Level.String(), newEntry.Rlevel.String())
+	} else {
+		fmt.Fprintf(b, "[%s] ", newEntry.Level.String())
+	}
+	appendValue(b, newEntry.Message)
+	for key, value := range newEntry.Data {
+		appendKeyValue(b, key, value)
+	}
+	b.WriteByte('\n')
+	s := bytes.NewBuffer(b.Bytes())
+	return s.String()
+}
+
+func appendValue(b *bytes.Buffer, value interface{}) {
+	if _, ok := value.(string); ok {
+		fmt.Fprintf(b, "%s ", value)
+	} else {
+		fmt.Fprintf(b, "%v ", value)
+	}
+}
+
+type keyvalueFormatter struct {
+}
+
+// ex. _time=2016-02-10T09:15:25.498-08:00 _level=INFO _msg=This is a message from test in key-value format
+
+func (*keyvalueFormatter) format(newEntry *logEntry) string {
+	b := &bytes.Buffer{}
+	appendKeyValue(b, _TIME, newEntry.Time)
+	appendKeyValue(b, _LEVEL, newEntry.Level.String())
+	if newEntry.Rlevel != NONE {
+		appendKeyValue(b, _RLEVEL, newEntry.Rlevel.String())
+	}
+	appendKeyValue(b, _MSG, newEntry.Message)
+	for key, value := range newEntry.Data {
+		appendKeyValue(b, key, value)
+	}
+	b.WriteByte('\n')
+	s := bytes.NewBuffer(b.Bytes())
+	return s.String()
+}
+
+func appendKeyValue(b *bytes.Buffer, key, value interface{}) {
+	if _, ok := value.(string); ok {
+		fmt.Fprintf(b, "%v=%s ", key, value)
+	} else {
+		fmt.Fprintf(b, "%v=%v ", key, value)
+	}
+}
+
+type jsonFormatter struct {
+}
+
+// ex. {"_level":"INFO","_msg":"This is a message from test in json format","_time":"2016-02-10T09:12:59.518-08:00"}
+
+func (*jsonFormatter) format(newEntry *logEntry) string {
+	if newEntry.Data == nil {
+		newEntry.Data = make(Map, 5)
+	}
+	newEntry.Data[_TIME] = newEntry.Time
+	newEntry.Data[_LEVEL] = newEntry.Level.String()
+	if newEntry.Rlevel != NONE {
+		newEntry.Data[_RLEVEL] = newEntry.Rlevel.String()
+	}
+	newEntry.Data[_MSG] = newEntry.Message
+	serialized, _ := json.Marshal(newEntry.Data)
+	s := bytes.NewBuffer(append(serialized, '\n'))
+	return s.String()
+}
diff --git a/vendor/github.com/couchbase/goutils/scramsha/scramsha.go b/vendor/github.com/couchbase/goutils/scramsha/scramsha.go
new file mode 100644
index 0000000000..b234bfc8a9
--- /dev/null
+++ b/vendor/github.com/couchbase/goutils/scramsha/scramsha.go
@@ -0,0 +1,207 @@
+// @author Couchbase <info@couchbase.com>
+// @copyright 2018 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package scramsha provides implementation of client side SCRAM-SHA
+// according to https://tools.ietf.org/html/rfc5802
+package scramsha
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha1"
+	"crypto/sha256"
+	"crypto/sha512"
+	"encoding/base64"
+	"fmt"
+	"github.com/pkg/errors"
+	"golang.org/x/crypto/pbkdf2"
+	"hash"
+	"strconv"
+	"strings"
+)
+
+func hmacHash(message []byte, secret []byte, hashFunc func() hash.Hash) []byte {
+	h := hmac.New(hashFunc, secret)
+	h.Write(message)
+	return h.Sum(nil)
+}
+
+func shaHash(message []byte, hashFunc func() hash.Hash) []byte {
+	h := hashFunc()
+	h.Write(message)
+	return h.Sum(nil)
+}
+
+func generateClientNonce(size int) (string, error) {
+	randomBytes := make([]byte, size)
+	_, err := rand.Read(randomBytes)
+	if err != nil {
+		return "", errors.Wrap(err, "Unable to generate nonce")
+	}
+	return base64.StdEncoding.EncodeToString(randomBytes), nil
+}
+
+// ScramSha provides context for SCRAM-SHA handling
+type ScramSha struct {
+	hashSize       int
+	hashFunc       func() hash.Hash
+	clientNonce    string
+	serverNonce    string
+	salt           []byte
+	i              int
+	saltedPassword []byte
+	authMessage    string
+}
+
+var knownMethods = []string{"SCRAM-SHA512", "SCRAM-SHA256", "SCRAM-SHA1"}
+
+// BestMethod returns SCRAM-SHA method we consider the best out of suggested
+// by server
+func BestMethod(methods string) (string, error) {
+	for _, m := range knownMethods {
+		if strings.Index(methods, m) != -1 {
+			return m, nil
+		}
+	}
+	return "", errors.Errorf(
+		"None of the server suggested methods [%s] are supported",
+		methods)
+}
+
+// NewScramSha creates context for SCRAM-SHA handling
+func NewScramSha(method string) (*ScramSha, error) {
+	s := &ScramSha{}
+
+	if method == knownMethods[0] {
+		s.hashFunc = sha512.New
+		s.hashSize = 64
+	} else if method == knownMethods[1] {
+		s.hashFunc = sha256.New
+		s.hashSize = 32
+	} else if method == knownMethods[2] {
+		s.hashFunc = sha1.New
+		s.hashSize = 20
+	} else {
+		return nil, errors.Errorf("Unsupported method %s", method)
+	}
+	return s, nil
+}
+
+// GetStartRequest builds start SCRAM-SHA request to be sent to server
+func (s *ScramSha) GetStartRequest(user string) (string, error) {
+	var err error
+	s.clientNonce, err = generateClientNonce(24)
+	if err != nil {
+		return "", errors.Wrapf(err, "Unable to generate SCRAM-SHA "+
+			"start request for user %s", user)
+	}
+
+	message := fmt.Sprintf("n,,n=%s,r=%s", user, s.clientNonce)
+	s.authMessage = message[3:]
+	return message, nil
+}
+
+// HandleStartResponse handles server response on start SCRAM-SHA request
+func (s *ScramSha) HandleStartResponse(response string) error {
+	parts := strings.Split(response, ",")
+	if len(parts) != 3 {
+		return errors.Errorf("expected 3 fields in first SCRAM-SHA-1 "+
+			"server message %s", response)
+	}
+	if !strings.HasPrefix(parts[0], "r=") || len(parts[0]) < 3 {
+		return errors.Errorf("Server sent an invalid nonce %s",
+			parts[0])
+	}
+	if !strings.HasPrefix(parts[1], "s=") || len(parts[1]) < 3 {
+		return errors.Errorf("Server sent an invalid salt %s", parts[1])
+	}
+	if !strings.HasPrefix(parts[2], "i=") || len(parts[2]) < 3 {
+		return errors.Errorf("Server sent an invalid iteration count %s",
+			parts[2])
+	}
+
+	s.serverNonce = parts[0][2:]
+	encodedSalt := parts[1][2:]
+	var err error
+	s.i, err = strconv.Atoi(parts[2][2:])
+	if err != nil {
+		return errors.Errorf("Iteration count %s must be integer.",
+			parts[2][2:])
+	}
+
+	if s.i < 1 {
+		return errors.New("Iteration count should be positive")
+	}
+
+	if !strings.HasPrefix(s.serverNonce, s.clientNonce) {
+		return errors.Errorf("Server nonce %s doesn't contain client"+
+			" nonce %s", s.serverNonce, s.clientNonce)
+	}
+
+	s.salt, err = base64.StdEncoding.DecodeString(encodedSalt)
+	if err != nil {
+		return errors.Wrapf(err, "Unable to decode salt %s",
+			encodedSalt)
+	}
+
+	s.authMessage = s.authMessage + "," + response
+	return nil
+}
+
+// GetFinalRequest builds final SCRAM-SHA request to be sent to server
+func (s *ScramSha) GetFinalRequest(pass string) string {
+	clientFinalMessageBare := "c=biws,r=" + s.serverNonce
+	s.authMessage = s.authMessage + "," + clientFinalMessageBare
+
+	s.saltedPassword = pbkdf2.Key([]byte(pass), s.salt, s.i,
+		s.hashSize, s.hashFunc)
+
+	clientKey := hmacHash([]byte("Client Key"), s.saltedPassword, s.hashFunc)
+	storedKey := shaHash(clientKey, s.hashFunc)
+	clientSignature := hmacHash([]byte(s.authMessage), storedKey, s.hashFunc)
+
+	clientProof := make([]byte, len(clientSignature))
+	for i := 0; i < len(clientSignature); i++ {
+		clientProof[i] = clientKey[i] ^ clientSignature[i]
+	}
+
+	return clientFinalMessageBare + ",p=" +
+		base64.StdEncoding.EncodeToString(clientProof)
+}
+
+// HandleFinalResponse handles server's response on final SCRAM-SHA request
+func (s *ScramSha) HandleFinalResponse(response string) error {
+	if strings.Contains(response, ",") ||
+		!strings.HasPrefix(response, "v=") {
+		return errors.Errorf("Server sent an invalid final message %s",
+			response)
+	}
+
+	decodedMessage, err := base64.StdEncoding.DecodeString(response[2:])
+	if err != nil {
+		return errors.Wrapf(err, "Unable to decode server message %s",
+			response[2:])
+	}
+	serverKey := hmacHash([]byte("Server Key"), s.saltedPassword,
+		s.hashFunc)
+	serverSignature := hmacHash([]byte(s.authMessage), serverKey,
+		s.hashFunc)
+	if string(decodedMessage) != string(serverSignature) {
+		return errors.Errorf("Server proof %s doesn't match "+
+			"the expected: %s",
+			string(decodedMessage), string(serverSignature))
+	}
+	return nil
+}
diff --git a/vendor/github.com/couchbase/goutils/scramsha/scramsha_http.go b/vendor/github.com/couchbase/goutils/scramsha/scramsha_http.go
new file mode 100644
index 0000000000..19f32b3134
--- /dev/null
+++ b/vendor/github.com/couchbase/goutils/scramsha/scramsha_http.go
@@ -0,0 +1,252 @@
+// @author Couchbase <info@couchbase.com>
+// @copyright 2018 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package scramsha provides implementation of client side SCRAM-SHA
+// via Http according to https://tools.ietf.org/html/rfc7804
+package scramsha
+
+import (
+	"encoding/base64"
+	"github.com/pkg/errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"strings"
+)
+
+// consts used to parse scramsha response from target
+const (
+	WWWAuthenticate    = "WWW-Authenticate"
+	AuthenticationInfo = "Authentication-Info"
+	Authorization      = "Authorization"
+	DataPrefix         = "data="
+	SidPrefix          = "sid="
+)
+
+// Request provides implementation of http request that can be retried
+type Request struct {
+	body io.ReadSeeker
+
+	// Embed an HTTP request directly. This makes a *Request act exactly
+	// like an *http.Request so that all meta methods are supported.
+	*http.Request
+}
+
+type lenReader interface {
+	Len() int
+}
+
+// NewRequest creates http request that can be retried
+func NewRequest(method, url string, body io.ReadSeeker) (*Request, error) {
+	// Wrap the body in a noop ReadCloser if non-nil. This prevents the
+	// reader from being closed by the HTTP client.
+	var rcBody io.ReadCloser
+	if body != nil {
+		rcBody = ioutil.NopCloser(body)
+	}
+
+	// Make the request with the noop-closer for the body.
+	httpReq, err := http.NewRequest(method, url, rcBody)
+	if err != nil {
+		return nil, err
+	}
+
+	// Check if we can set the Content-Length automatically.
+	if lr, ok := body.(lenReader); ok {
+		httpReq.ContentLength = int64(lr.Len())
+	}
+
+	return &Request{body, httpReq}, nil
+}
+
+func encode(str string) string {
+	return base64.StdEncoding.EncodeToString([]byte(str))
+}
+
+func decode(str string) (string, error) {
+	bytes, err := base64.StdEncoding.DecodeString(str)
+	if err != nil {
+		return "", errors.Errorf("Cannot base64 decode %s",
+			str)
+	}
+	return string(bytes), err
+}
+
+func trimPrefix(s, prefix string) (string, error) {
+	l := len(s)
+	trimmed := strings.TrimPrefix(s, prefix)
+	if l == len(trimmed) {
+		return trimmed, errors.Errorf("Prefix %s not found in %s",
+			prefix, s)
+	}
+	return trimmed, nil
+}
+
+func drainBody(resp *http.Response) {
+	defer resp.Body.Close()
+	io.Copy(ioutil.Discard, resp.Body)
+}
+
+// DoScramSha performs SCRAM-SHA handshake via Http
+func DoScramSha(req *Request,
+	username string,
+	password string,
+	client *http.Client) (*http.Response, error) {
+
+	method := "SCRAM-SHA-512"
+	s, err := NewScramSha("SCRAM-SHA512")
+	if err != nil {
+		return nil, errors.Wrap(err,
+			"Unable to initialize SCRAM-SHA handler")
+	}
+
+	message, err := s.GetStartRequest(username)
+	if err != nil {
+		return nil, err
+	}
+
+	encodedMessage := method + " " + DataPrefix + encode(message)
+
+	req.Header.Set(Authorization, encodedMessage)
+
+	res, err := client.Do(req.Request)
+	if err != nil {
+		return nil, errors.Wrap(err, "Problem sending SCRAM-SHA start"+
+			"request")
+	}
+
+	if res.StatusCode != http.StatusUnauthorized {
+		return res, nil
+	}
+
+	authHeader := res.Header.Get(WWWAuthenticate)
+	if authHeader == "" {
+		drainBody(res)
+		return nil, errors.Errorf("Header %s is not populated in "+
+			"SCRAM-SHA start response", WWWAuthenticate)
+	}
+
+	authHeader, err = trimPrefix(authHeader, method+" ")
+	if err != nil {
+		if strings.HasPrefix(authHeader, "Basic ") {
+			// user not found
+			return res, nil
+		}
+		drainBody(res)
+		return nil, errors.Wrapf(err, "Error while parsing SCRAM-SHA "+
+			"start response %s", authHeader)
+	}
+
+	drainBody(res)
+
+	sid, response, err := parseSidAndData(authHeader)
+	if err != nil {
+		return nil, errors.Wrapf(err, "Error while parsing SCRAM-SHA "+
+			"start response %s", authHeader)
+	}
+
+	err = s.HandleStartResponse(response)
+	if err != nil {
+		return nil, errors.Wrapf(err, "Error parsing SCRAM-SHA start "+
+			"response %s", response)
+	}
+
+	message = s.GetFinalRequest(password)
+	encodedMessage = method + " " + SidPrefix + sid + "," + DataPrefix +
+		encode(message)
+
+	req.Header.Set(Authorization, encodedMessage)
+
+	// rewind request body so it can be resent again
+	if req.body != nil {
+		if _, err = req.body.Seek(0, 0); err != nil {
+			return nil, errors.Errorf("Failed to seek body: %v",
+				err)
+		}
+	}
+
+	res, err = client.Do(req.Request)
+	if err != nil {
+		return nil, errors.Wrap(err, "Problem sending SCRAM-SHA final"+
+			"request")
+	}
+
+	if res.StatusCode == http.StatusUnauthorized {
+		// TODO retrieve and return error
+		return res, nil
+	}
+
+	if res.StatusCode >= http.StatusInternalServerError {
+		// in this case we cannot expect server to set headers properly
+		return res, nil
+	}
+
+	authHeader = res.Header.Get(AuthenticationInfo)
+	if authHeader == "" {
+		drainBody(res)
+		return nil, errors.Errorf("Header %s is not populated in "+
+			"SCRAM-SHA final response", AuthenticationInfo)
+	}
+
+	finalSid, response, err := parseSidAndData(authHeader)
+	if err != nil {
+		drainBody(res)
+		return nil, errors.Wrapf(err, "Error while parsing SCRAM-SHA "+
+			"final response %s", authHeader)
+	}
+
+	if finalSid != sid {
+		drainBody(res)
+		return nil, errors.Errorf("Sid %s returned by server "+
+			"doesn't match the original sid %s", finalSid, sid)
+	}
+
+	err = s.HandleFinalResponse(response)
+	if err != nil {
+		drainBody(res)
+		return nil, errors.Wrapf(err,
+			"Error handling SCRAM-SHA final server response %s",
+			response)
+	}
+	return res, nil
+}
+
+func parseSidAndData(authHeader string) (string, string, error) {
+	sidIndex := strings.Index(authHeader, SidPrefix)
+	if sidIndex < 0 {
+		return "", "", errors.Errorf("Cannot find %s in %s",
+			SidPrefix, authHeader)
+	}
+
+	sidEndIndex := strings.Index(authHeader, ",")
+	if sidEndIndex < 0 {
+		return "", "", errors.Errorf("Cannot find ',' in %s",
+			authHeader)
+	}
+
+	sid := authHeader[sidIndex+len(SidPrefix) : sidEndIndex]
+
+	dataIndex := strings.Index(authHeader, DataPrefix)
+	if dataIndex < 0 {
+		return "", "", errors.Errorf("Cannot find %s in %s",
+			DataPrefix, authHeader)
+	}
+
+	data, err := decode(authHeader[dataIndex+len(DataPrefix):])
+	if err != nil {
+		return "", "", err
+	}
+	return sid, data, nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/LICENSE b/vendor/github.com/couchbaselabs/go-couchbase/LICENSE
new file mode 100644
index 0000000000..0b23ef358e
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2013  Couchbase, Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/audit.go b/vendor/github.com/couchbaselabs/go-couchbase/audit.go
new file mode 100644
index 0000000000..3db7d9f9ff
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/audit.go
@@ -0,0 +1,32 @@
+package couchbase
+
+import ()
+
+// Sample data:
+// {"disabled":["12333", "22244"],"uid":"132492431","auditdEnabled":true,
+//  "disabledUsers":[{"name":"bill","domain":"local"},{"name":"bob","domain":"local"}],
+//  "logPath":"/Users/johanlarson/Library/Application Support/Couchbase/var/lib/couchbase/logs",
+//  "rotateInterval":86400,"rotateSize":20971520}
+type AuditSpec struct {
+	Disabled       []uint32    `json:"disabled"`
+	Uid            string      `json:"uid"`
+	AuditdEnabled  bool        `json:"auditdEnabled`
+	DisabledUsers  []AuditUser `json:"disabledUsers"`
+	LogPath        string      `json:"logPath"`
+	RotateInterval int64       `json:"rotateInterval"`
+	RotateSize     int64       `json:"rotateSize"`
+}
+
+type AuditUser struct {
+	Name   string `json:"name"`
+	Domain string `json:"domain"`
+}
+
+func (c *Client) GetAuditSpec() (*AuditSpec, error) {
+	ret := &AuditSpec{}
+	err := c.parseURLResponse("/settings/audit", ret)
+	if err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/client.go b/vendor/github.com/couchbaselabs/go-couchbase/client.go
new file mode 100644
index 0000000000..43c3382960
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/client.go
@@ -0,0 +1,1385 @@
+/*
+Package couchbase provides a smart client for go.
+
+Usage:
+
+ client, err := couchbase.Connect("http://myserver:8091/")
+ handleError(err)
+ pool, err := client.GetPool("default")
+ handleError(err)
+ bucket, err := pool.GetBucket("MyAwesomeBucket")
+ handleError(err)
+ ...
+
+or a shortcut for the bucket directly
+
+ bucket, err := couchbase.GetBucket("http://myserver:8091/", "default", "default")
+
+in any case, you can specify authentication credentials using
+standard URL userinfo syntax:
+
+ b, err := couchbase.GetBucket("http://bucketname:bucketpass@myserver:8091/",
+         "default", "bucket")
+*/
+package couchbase
+
+import (
+	"encoding/binary"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"runtime"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+	"unsafe"
+
+	"github.com/couchbase/gomemcached"
+	"github.com/couchbase/gomemcached/client" // package name is 'memcached'
+	"github.com/couchbase/goutils/logging"
+)
+
+// Mutation Token
+type MutationToken struct {
+	VBid  uint16 // vbucket id
+	Guard uint64 // vbuuid
+	Value uint64 // sequence number
+}
+
+// Maximum number of times to retry a chunk of a bulk get on error.
+var MaxBulkRetries = 5000
+var backOffDuration time.Duration = 100 * time.Millisecond
+var MaxBackOffRetries = 25 // exponentail backOff result in over 30sec (25*13*0.1s)
+
+// If this is set to a nonzero duration, Do() and ViewCustom() will log a warning if the call
+// takes longer than that.
+var SlowServerCallWarningThreshold time.Duration
+
+func slowLog(startTime time.Time, format string, args ...interface{}) {
+	if elapsed := time.Now().Sub(startTime); elapsed > SlowServerCallWarningThreshold {
+		pc, _, _, _ := runtime.Caller(2)
+		caller := runtime.FuncForPC(pc).Name()
+		logging.Infof("go-couchbase: "+format+" in "+caller+" took "+elapsed.String(), args...)
+	}
+}
+
+// Return true if error is KEY_ENOENT. Required by cbq-engine
+func IsKeyEExistsError(err error) bool {
+
+	res, ok := err.(*gomemcached.MCResponse)
+	if ok && res.Status == gomemcached.KEY_EEXISTS {
+		return true
+	}
+
+	return false
+}
+
+// Return true if error is KEY_ENOENT. Required by cbq-engine
+func IsKeyNoEntError(err error) bool {
+
+	res, ok := err.(*gomemcached.MCResponse)
+	if ok && res.Status == gomemcached.KEY_ENOENT {
+		return true
+	}
+
+	return false
+}
+
+// Return true if error suggests a bucket refresh is required. Required by cbq-engine
+func IsRefreshRequired(err error) bool {
+
+	res, ok := err.(*gomemcached.MCResponse)
+	if ok && (res.Status == gomemcached.NO_BUCKET || res.Status == gomemcached.NOT_MY_VBUCKET) {
+		return true
+	}
+
+	return false
+}
+
+// ClientOpCallback is called for each invocation of Do.
+var ClientOpCallback func(opname, k string, start time.Time, err error)
+
+// Do executes a function on a memcached connection to the node owning key "k"
+//
+// Note that this automatically handles transient errors by replaying
+// your function on a "not-my-vbucket" error, so don't assume
+// your command will only be executed only once.
+func (b *Bucket) Do(k string, f func(mc *memcached.Client, vb uint16) error) (err error) {
+	return b.Do2(k, f, true)
+}
+
+func (b *Bucket) Do2(k string, f func(mc *memcached.Client, vb uint16) error, deadline bool) (err error) {
+	if SlowServerCallWarningThreshold > 0 {
+		defer slowLog(time.Now(), "call to Do(%q)", k)
+	}
+
+	vb := b.VBHash(k)
+	maxTries := len(b.Nodes()) * 2
+	for i := 0; i < maxTries; i++ {
+		conn, pool, err := b.getConnectionToVBucket(vb)
+		if err != nil {
+			if isConnError(err) && backOff(i, maxTries, backOffDuration, true) {
+				b.Refresh()
+				continue
+			}
+			return err
+		}
+
+		if deadline && DefaultTimeout > 0 {
+			conn.SetDeadline(getDeadline(noDeadline, DefaultTimeout))
+			err = f(conn, uint16(vb))
+			conn.SetDeadline(noDeadline)
+		} else {
+			err = f(conn, uint16(vb))
+		}
+
+		var retry bool
+		discard := isOutOfBoundsError(err)
+
+		// MB-30967 / MB-31001 implement back off for transient errors
+		if resp, ok := err.(*gomemcached.MCResponse); ok {
+			switch resp.Status {
+			case gomemcached.NOT_MY_VBUCKET:
+				b.Refresh()
+				// MB-28842: in case of NMVB, check if the node is still part of the map
+				// and ditch the connection if it isn't.
+				discard = b.checkVBmap(pool.Node())
+				retry = true
+			case gomemcached.NOT_SUPPORTED:
+				discard = true
+				retry = true
+			case gomemcached.ENOMEM:
+				fallthrough
+			case gomemcached.TMPFAIL:
+				retry = backOff(i, maxTries, backOffDuration, true)
+			default:
+				retry = false
+			}
+		} else if err != nil && isConnError(err) && backOff(i, maxTries, backOffDuration, true) {
+			retry = true
+		}
+
+		if discard {
+			pool.Discard(conn)
+		} else {
+			pool.Return(conn)
+		}
+
+		if !retry {
+			return err
+		}
+	}
+
+	return fmt.Errorf("unable to complete action after %v attemps", maxTries)
+}
+
+type GatheredStats struct {
+	Server string
+	Stats  map[string]string
+	Err    error
+}
+
+func getStatsParallel(sn string, b *Bucket, offset int, which string,
+	ch chan<- GatheredStats) {
+	pool := b.getConnPool(offset)
+	var gatheredStats GatheredStats
+
+	conn, err := pool.Get()
+	defer func() {
+		pool.Return(conn)
+		ch <- gatheredStats
+	}()
+
+	if err != nil {
+		gatheredStats = GatheredStats{Server: sn, Err: err}
+	} else {
+		sm, err := conn.StatsMap(which)
+		gatheredStats = GatheredStats{Server: sn, Stats: sm, Err: err}
+	}
+}
+
+// GetStats gets a set of stats from all servers.
+//
+// Returns a map of server ID -> map of stat key to map value.
+func (b *Bucket) GetStats(which string) map[string]map[string]string {
+	rv := map[string]map[string]string{}
+	for server, gs := range b.GatherStats(which) {
+		if len(gs.Stats) > 0 {
+			rv[server] = gs.Stats
+		}
+	}
+	return rv
+}
+
+// GatherStats returns a map of server ID -> GatheredStats from all servers.
+func (b *Bucket) GatherStats(which string) map[string]GatheredStats {
+	vsm := b.VBServerMap()
+	if vsm.ServerList == nil {
+		return nil
+	}
+
+	// Go grab all the things at once.
+	ch := make(chan GatheredStats, len(vsm.ServerList))
+	for i, sn := range vsm.ServerList {
+		go getStatsParallel(sn, b, i, which, ch)
+	}
+
+	// Gather the results
+	rv := map[string]GatheredStats{}
+	for range vsm.ServerList {
+		gs := <-ch
+		rv[gs.Server] = gs
+	}
+	return rv
+}
+
+// Get bucket count through the bucket stats
+func (b *Bucket) GetCount(refresh bool) (count int64, err error) {
+	if refresh {
+		b.Refresh()
+	}
+
+	var cnt int64
+	for _, gs := range b.GatherStats("") {
+		if len(gs.Stats) > 0 {
+			cnt, err = strconv.ParseInt(gs.Stats["curr_items"], 10, 64)
+			if err != nil {
+				return 0, err
+			}
+			count += cnt
+		}
+	}
+
+	return count, nil
+}
+
+func isAuthError(err error) bool {
+	estr := err.Error()
+	return strings.Contains(estr, "Auth failure")
+}
+
+func IsReadTimeOutError(err error) bool {
+	estr := err.Error()
+	return strings.Contains(estr, "read tcp") ||
+		strings.Contains(estr, "i/o timeout")
+}
+
+func isTimeoutError(err error) bool {
+	estr := err.Error()
+	return strings.Contains(estr, "i/o timeout") ||
+		strings.Contains(estr, "connection timed out") ||
+		strings.Contains(estr, "no route to host")
+}
+
+// Errors that are not considered fatal for our fetch loop
+func isConnError(err error) bool {
+	if err == io.EOF {
+		return true
+	}
+	estr := err.Error()
+	return strings.Contains(estr, "broken pipe") ||
+		strings.Contains(estr, "connection reset") ||
+		strings.Contains(estr, "connection refused") ||
+		strings.Contains(estr, "connection pool is closed")
+}
+
+func isOutOfBoundsError(err error) bool {
+	return err != nil && strings.Contains(err.Error(), "Out of Bounds error")
+
+}
+
+func getDeadline(reqDeadline time.Time, duration time.Duration) time.Time {
+	if reqDeadline.IsZero() && duration > 0 {
+		return time.Now().Add(duration)
+	}
+	return reqDeadline
+}
+
+func backOff(attempt, maxAttempts int, duration time.Duration, exponential bool) bool {
+	if attempt < maxAttempts {
+		// 0th attempt return immediately
+		if attempt > 0 {
+			if exponential {
+				duration = time.Duration(attempt) * duration
+			}
+			time.Sleep(duration)
+		}
+		return true
+	}
+
+	return false
+}
+
+func (b *Bucket) doBulkGet(vb uint16, keys []string, reqDeadline time.Time,
+	ch chan<- map[string]*gomemcached.MCResponse, ech chan<- error, subPaths []string,
+	eStatus *errorStatus) {
+	if SlowServerCallWarningThreshold > 0 {
+		defer slowLog(time.Now(), "call to doBulkGet(%d, %d keys)", vb, len(keys))
+	}
+
+	rv := _STRING_MCRESPONSE_POOL.Get()
+	attempts := 0
+	backOffAttempts := 0
+	done := false
+	bname := b.Name
+	for ; attempts < MaxBulkRetries && !done && !eStatus.errStatus; attempts++ {
+
+		if len(b.VBServerMap().VBucketMap) < int(vb) {
+			//fatal
+			err := fmt.Errorf("vbmap smaller than requested for %v", bname)
+			logging.Errorf("go-couchbase: %v vb %d vbmap len %d", err.Error(), vb, len(b.VBServerMap().VBucketMap))
+			ech <- err
+			return
+		}
+
+		masterID := b.VBServerMap().VBucketMap[vb][0]
+
+		if masterID < 0 {
+			// fatal
+			err := fmt.Errorf("No master node available for %v vb %d", bname, vb)
+			logging.Errorf("%v", err.Error())
+			ech <- err
+			return
+		}
+
+		// This stack frame exists to ensure we can clean up
+		// connection at a reasonable time.
+		err := func() error {
+			pool := b.getConnPool(masterID)
+			conn, err := pool.Get()
+			if err != nil {
+				if isAuthError(err) || isTimeoutError(err) {
+					logging.Errorf("Fatal Error %v : %v", bname, err)
+					ech <- err
+					return err
+				} else if isConnError(err) {
+					if !backOff(backOffAttempts, MaxBackOffRetries, backOffDuration, true) {
+						logging.Errorf("Connection Error %v : %v", bname, err)
+						ech <- err
+						return err
+					}
+					b.Refresh()
+					backOffAttempts++
+				}
+				logging.Infof("Pool Get returned %v: %v", bname, err)
+				// retry
+				return nil
+			}
+
+			conn.SetDeadline(getDeadline(reqDeadline, DefaultTimeout))
+			err = conn.GetBulk(vb, keys, rv, subPaths)
+			conn.SetDeadline(noDeadline)
+
+			discard := false
+			defer func() {
+				if discard {
+					pool.Discard(conn)
+				} else {
+					pool.Return(conn)
+				}
+			}()
+
+			switch err.(type) {
+			case *gomemcached.MCResponse:
+				notSMaxTries := len(b.Nodes()) * 2
+				st := err.(*gomemcached.MCResponse).Status
+				if st == gomemcached.NOT_MY_VBUCKET || (st == gomemcached.NOT_SUPPORTED && attempts < notSMaxTries) {
+					b.Refresh()
+					discard = b.checkVBmap(pool.Node())
+					return nil // retry
+				} else if st == gomemcached.EBUSY || st == gomemcached.LOCKED {
+					if (attempts % (MaxBulkRetries / 100)) == 0 {
+						logging.Infof("Retrying Memcached error (%v) FOR %v(vbid:%d, keys:<ud>%v</ud>)",
+							err.Error(), bname, vb, keys)
+					}
+					return nil // retry
+				} else if (st == gomemcached.ENOMEM || st == gomemcached.TMPFAIL) && backOff(backOffAttempts, MaxBackOffRetries, backOffDuration, true) {
+					// MB-30967 / MB-31001 use backoff for TMPFAIL too
+					backOffAttempts++
+					logging.Infof("Retrying Memcached error (%v) FOR %v(vbid:%d, keys:<ud>%v</ud>)",
+						err.Error(), bname, vb, keys)
+					return nil // retry
+				}
+				ech <- err
+				return err
+			case error:
+				if isOutOfBoundsError(err) {
+					// We got an out of bound error, retry the operation
+					discard = true
+					return nil
+				} else if isConnError(err) && backOff(backOffAttempts, MaxBackOffRetries, backOffDuration, true) {
+					backOffAttempts++
+					logging.Errorf("Connection Error: %s. Refreshing bucket %v (vbid:%v,keys:<ud>%v</ud>)",
+						err.Error(), bname, vb, keys)
+					discard = true
+					b.Refresh()
+					return nil // retry
+				}
+				ech <- err
+				ch <- rv
+				return err
+			}
+
+			done = true
+			return nil
+		}()
+
+		if err != nil {
+			return
+		}
+	}
+
+	if attempts >= MaxBulkRetries {
+		err := fmt.Errorf("bulkget exceeded MaxBulkRetries for %v(vbid:%d,keys:<ud>%v</ud>)", bname, vb, keys)
+		logging.Errorf("%v", err.Error())
+		ech <- err
+	}
+
+	ch <- rv
+}
+
+type errorStatus struct {
+	errStatus bool
+}
+
+type vbBulkGet struct {
+	b           *Bucket
+	ch          chan<- map[string]*gomemcached.MCResponse
+	ech         chan<- error
+	k           uint16
+	keys        []string
+	reqDeadline time.Time
+	wg          *sync.WaitGroup
+	subPaths    []string
+	groupError  *errorStatus
+}
+
+const _NUM_CHANNELS = 5
+
+var _NUM_CHANNEL_WORKERS = (runtime.NumCPU() + 1) / 2
+var DefaultDialTimeout = time.Duration(0)
+var DefaultTimeout = time.Duration(0)
+var noDeadline = time.Time{}
+
+// Buffer 4k requests per worker
+var _VB_BULK_GET_CHANNELS []chan *vbBulkGet
+
+func InitBulkGet() {
+
+	DefaultDialTimeout = 20 * time.Second
+	DefaultTimeout = 120 * time.Second
+
+	memcached.SetDefaultDialTimeout(DefaultDialTimeout)
+
+	_VB_BULK_GET_CHANNELS = make([]chan *vbBulkGet, _NUM_CHANNELS)
+
+	for i := 0; i < _NUM_CHANNELS; i++ {
+		channel := make(chan *vbBulkGet, 16*1024*_NUM_CHANNEL_WORKERS)
+		_VB_BULK_GET_CHANNELS[i] = channel
+
+		for j := 0; j < _NUM_CHANNEL_WORKERS; j++ {
+			go vbBulkGetWorker(channel)
+		}
+	}
+}
+
+func vbBulkGetWorker(ch chan *vbBulkGet) {
+	defer func() {
+		// Workers cannot panic and die
+		recover()
+		go vbBulkGetWorker(ch)
+	}()
+
+	for vbg := range ch {
+		vbDoBulkGet(vbg)
+	}
+}
+
+func vbDoBulkGet(vbg *vbBulkGet) {
+	defer vbg.wg.Done()
+	defer func() {
+		// Workers cannot panic and die
+		recover()
+	}()
+	vbg.b.doBulkGet(vbg.k, vbg.keys, vbg.reqDeadline, vbg.ch, vbg.ech, vbg.subPaths, vbg.groupError)
+}
+
+var _ERR_CHAN_FULL = fmt.Errorf("Data request queue full, aborting query.")
+
+func (b *Bucket) processBulkGet(kdm map[uint16][]string, reqDeadline time.Time,
+	ch chan<- map[string]*gomemcached.MCResponse, ech chan<- error, subPaths []string,
+	eStatus *errorStatus) {
+
+	defer close(ch)
+	defer close(ech)
+
+	wg := &sync.WaitGroup{}
+
+	for k, keys := range kdm {
+
+		// GetBulk() group has error donot Queue items for this group
+		if eStatus.errStatus {
+			break
+		}
+
+		vbg := &vbBulkGet{
+			b:           b,
+			ch:          ch,
+			ech:         ech,
+			k:           k,
+			keys:        keys,
+			reqDeadline: reqDeadline,
+			wg:          wg,
+			subPaths:    subPaths,
+			groupError:  eStatus,
+		}
+
+		wg.Add(1)
+
+		// Random int
+		// Right shift to avoid 8-byte alignment, and take low bits
+		c := (uintptr(unsafe.Pointer(vbg)) >> 4) % _NUM_CHANNELS
+
+		select {
+		case _VB_BULK_GET_CHANNELS[c] <- vbg:
+			// No-op
+		default:
+			// Buffer full, abandon the bulk get
+			ech <- _ERR_CHAN_FULL
+			wg.Add(-1)
+		}
+	}
+
+	// Wait for my vb bulk gets
+	wg.Wait()
+}
+
+type multiError []error
+
+func (m multiError) Error() string {
+	if len(m) == 0 {
+		panic("Error of none")
+	}
+
+	return fmt.Sprintf("{%v errors, starting with %v}", len(m), m[0].Error())
+}
+
+// Convert a stream of errors from ech into a multiError (or nil) and
+// send down eout.
+//
+// At least one send is guaranteed on eout, but two is possible, so
+// buffer the out channel appropriately.
+func errorCollector(ech <-chan error, eout chan<- error, eStatus *errorStatus) {
+	defer func() { eout <- nil }()
+	var errs multiError
+	for e := range ech {
+		if !eStatus.errStatus && !IsKeyNoEntError(e) {
+			eStatus.errStatus = true
+		}
+
+		errs = append(errs, e)
+	}
+
+	if len(errs) > 0 {
+		eout <- errs
+	}
+}
+
+// Fetches multiple keys concurrently, with []byte values
+//
+// This is a wrapper around GetBulk which converts all values returned
+// by GetBulk from raw memcached responses into []byte slices.
+// Returns one document for duplicate keys
+func (b *Bucket) GetBulkRaw(keys []string) (map[string][]byte, error) {
+
+	resp, eout := b.getBulk(keys, noDeadline, nil)
+
+	rv := make(map[string][]byte, len(keys))
+	for k, av := range resp {
+		rv[k] = av.Body
+	}
+
+	b.ReleaseGetBulkPools(resp)
+	return rv, eout
+
+}
+
+// GetBulk fetches multiple keys concurrently.
+//
+// Unlike more convenient GETs, the entire response is returned in the
+// map array for each key.  Keys that were not found will not be included in
+// the map.
+
+func (b *Bucket) GetBulk(keys []string, reqDeadline time.Time, subPaths []string) (map[string]*gomemcached.MCResponse, error) {
+	return b.getBulk(keys, reqDeadline, subPaths)
+}
+
+func (b *Bucket) ReleaseGetBulkPools(rv map[string]*gomemcached.MCResponse) {
+	_STRING_MCRESPONSE_POOL.Put(rv)
+}
+
+func (b *Bucket) getBulk(keys []string, reqDeadline time.Time, subPaths []string) (map[string]*gomemcached.MCResponse, error) {
+	kdm := _VB_STRING_POOL.Get()
+	defer _VB_STRING_POOL.Put(kdm)
+	for _, k := range keys {
+		if k != "" {
+			vb := uint16(b.VBHash(k))
+			a, ok1 := kdm[vb]
+			if !ok1 {
+				a = _STRING_POOL.Get()
+			}
+			kdm[vb] = append(a, k)
+		}
+	}
+
+	eout := make(chan error, 2)
+	groupErrorStatus := &errorStatus{}
+
+	// processBulkGet will own both of these channels and
+	// guarantee they're closed before it returns.
+	ch := make(chan map[string]*gomemcached.MCResponse)
+	ech := make(chan error)
+
+	go errorCollector(ech, eout, groupErrorStatus)
+	go b.processBulkGet(kdm, reqDeadline, ch, ech, subPaths, groupErrorStatus)
+
+	var rv map[string]*gomemcached.MCResponse
+
+	for m := range ch {
+		if rv == nil {
+			rv = m
+			continue
+		}
+
+		for k, v := range m {
+			rv[k] = v
+		}
+		_STRING_MCRESPONSE_POOL.Put(m)
+	}
+
+	return rv, <-eout
+}
+
+// WriteOptions is the set of option flags availble for the Write
+// method.  They are ORed together to specify the desired request.
+type WriteOptions int
+
+const (
+	// Raw specifies that the value is raw []byte or nil; don't
+	// JSON-encode it.
+	Raw = WriteOptions(1 << iota)
+	// AddOnly indicates an item should only be written if it
+	// doesn't exist, otherwise ErrKeyExists is returned.
+	AddOnly
+	// Persist causes the operation to block until the server
+	// confirms the item is persisted.
+	Persist
+	// Indexable causes the operation to block until it's availble via the index.
+	Indexable
+	// Append indicates the given value should be appended to the
+	// existing value for the given key.
+	Append
+)
+
+var optNames = []struct {
+	opt  WriteOptions
+	name string
+}{
+	{Raw, "raw"},
+	{AddOnly, "addonly"}, {Persist, "persist"},
+	{Indexable, "indexable"}, {Append, "append"},
+}
+
+// String representation of WriteOptions
+func (w WriteOptions) String() string {
+	f := []string{}
+	for _, on := range optNames {
+		if w&on.opt != 0 {
+			f = append(f, on.name)
+			w &= ^on.opt
+		}
+	}
+	if len(f) == 0 || w != 0 {
+		f = append(f, fmt.Sprintf("0x%x", int(w)))
+	}
+	return strings.Join(f, "|")
+}
+
+// Error returned from Write with AddOnly flag, when key already exists in the bucket.
+var ErrKeyExists = errors.New("key exists")
+
+// General-purpose value setter.
+//
+// The Set, Add and Delete methods are just wrappers around this.  The
+// interpretation of `v` depends on whether the `Raw` option is
+// given. If it is, v must be a byte array or nil. (A nil value causes
+// a delete.) If `Raw` is not given, `v` will be marshaled as JSON
+// before being written. It must be JSON-marshalable and it must not
+// be nil.
+func (b *Bucket) Write(k string, flags, exp int, v interface{},
+	opt WriteOptions) (err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) {
+			ClientOpCallback(fmt.Sprintf("Write(%v)", opt), k, t, err)
+		}(time.Now())
+	}
+
+	var data []byte
+	if opt&Raw == 0 {
+		data, err = json.Marshal(v)
+		if err != nil {
+			return err
+		}
+	} else if v != nil {
+		data = v.([]byte)
+	}
+
+	var res *gomemcached.MCResponse
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		if opt&AddOnly != 0 {
+			res, err = memcached.UnwrapMemcachedError(
+				mc.Add(vb, k, flags, exp, data))
+			if err == nil && res.Status != gomemcached.SUCCESS {
+				if res.Status == gomemcached.KEY_EEXISTS {
+					err = ErrKeyExists
+				} else {
+					err = res
+				}
+			}
+		} else if opt&Append != 0 {
+			res, err = mc.Append(vb, k, data)
+		} else if data == nil {
+			res, err = mc.Del(vb, k)
+		} else {
+			res, err = mc.Set(vb, k, flags, exp, data)
+		}
+
+		return err
+	})
+
+	if err == nil && (opt&(Persist|Indexable) != 0) {
+		err = b.WaitForPersistence(k, res.Cas, data == nil)
+	}
+
+	return err
+}
+
+func (b *Bucket) WriteWithMT(k string, flags, exp int, v interface{},
+	opt WriteOptions) (mt *MutationToken, err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) {
+			ClientOpCallback(fmt.Sprintf("WriteWithMT(%v)", opt), k, t, err)
+		}(time.Now())
+	}
+
+	var data []byte
+	if opt&Raw == 0 {
+		data, err = json.Marshal(v)
+		if err != nil {
+			return nil, err
+		}
+	} else if v != nil {
+		data = v.([]byte)
+	}
+
+	var res *gomemcached.MCResponse
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		if opt&AddOnly != 0 {
+			res, err = memcached.UnwrapMemcachedError(
+				mc.Add(vb, k, flags, exp, data))
+			if err == nil && res.Status != gomemcached.SUCCESS {
+				if res.Status == gomemcached.KEY_EEXISTS {
+					err = ErrKeyExists
+				} else {
+					err = res
+				}
+			}
+		} else if opt&Append != 0 {
+			res, err = mc.Append(vb, k, data)
+		} else if data == nil {
+			res, err = mc.Del(vb, k)
+		} else {
+			res, err = mc.Set(vb, k, flags, exp, data)
+		}
+
+		if len(res.Extras) >= 16 {
+			vbuuid := uint64(binary.BigEndian.Uint64(res.Extras[0:8]))
+			seqNo := uint64(binary.BigEndian.Uint64(res.Extras[8:16]))
+			mt = &MutationToken{VBid: vb, Guard: vbuuid, Value: seqNo}
+		}
+
+		return err
+	})
+
+	if err == nil && (opt&(Persist|Indexable) != 0) {
+		err = b.WaitForPersistence(k, res.Cas, data == nil)
+	}
+
+	return mt, err
+}
+
+// Set a value in this bucket with Cas and return the new Cas value
+func (b *Bucket) Cas(k string, exp int, cas uint64, v interface{}) (uint64, error) {
+	return b.WriteCas(k, 0, exp, cas, v, 0)
+}
+
+// Set a value in this bucket with Cas without json encoding it
+func (b *Bucket) CasRaw(k string, exp int, cas uint64, v interface{}) (uint64, error) {
+	return b.WriteCas(k, 0, exp, cas, v, Raw)
+}
+
+func (b *Bucket) WriteCas(k string, flags, exp int, cas uint64, v interface{},
+	opt WriteOptions) (newCas uint64, err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) {
+			ClientOpCallback(fmt.Sprintf("Write(%v)", opt), k, t, err)
+		}(time.Now())
+	}
+
+	var data []byte
+	if opt&Raw == 0 {
+		data, err = json.Marshal(v)
+		if err != nil {
+			return 0, err
+		}
+	} else if v != nil {
+		data = v.([]byte)
+	}
+
+	var res *gomemcached.MCResponse
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err = mc.SetCas(vb, k, flags, exp, cas, data)
+		return err
+	})
+
+	if err == nil && (opt&(Persist|Indexable) != 0) {
+		err = b.WaitForPersistence(k, res.Cas, data == nil)
+	}
+
+	return res.Cas, err
+}
+
+// Extended CAS operation. These functions will return the mutation token, i.e vbuuid & guard
+func (b *Bucket) CasWithMeta(k string, flags int, exp int, cas uint64, v interface{}) (uint64, *MutationToken, error) {
+	return b.WriteCasWithMT(k, flags, exp, cas, v, 0)
+}
+
+func (b *Bucket) CasWithMetaRaw(k string, flags int, exp int, cas uint64, v interface{}) (uint64, *MutationToken, error) {
+	return b.WriteCasWithMT(k, flags, exp, cas, v, Raw)
+}
+
+func (b *Bucket) WriteCasWithMT(k string, flags, exp int, cas uint64, v interface{},
+	opt WriteOptions) (newCas uint64, mt *MutationToken, err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) {
+			ClientOpCallback(fmt.Sprintf("Write(%v)", opt), k, t, err)
+		}(time.Now())
+	}
+
+	var data []byte
+	if opt&Raw == 0 {
+		data, err = json.Marshal(v)
+		if err != nil {
+			return 0, nil, err
+		}
+	} else if v != nil {
+		data = v.([]byte)
+	}
+
+	var res *gomemcached.MCResponse
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err = mc.SetCas(vb, k, flags, exp, cas, data)
+		return err
+	})
+
+	if err != nil {
+		return 0, nil, err
+	}
+
+	// check for extras
+	if len(res.Extras) >= 16 {
+		vbuuid := uint64(binary.BigEndian.Uint64(res.Extras[0:8]))
+		seqNo := uint64(binary.BigEndian.Uint64(res.Extras[8:16]))
+		vb := b.VBHash(k)
+		mt = &MutationToken{VBid: uint16(vb), Guard: vbuuid, Value: seqNo}
+	}
+
+	if err == nil && (opt&(Persist|Indexable) != 0) {
+		err = b.WaitForPersistence(k, res.Cas, data == nil)
+	}
+
+	return res.Cas, mt, err
+}
+
+// Set a value in this bucket.
+// The value will be serialized into a JSON document.
+func (b *Bucket) Set(k string, exp int, v interface{}) error {
+	return b.Write(k, 0, exp, v, 0)
+}
+
+// Set a value in this bucket with with flags
+func (b *Bucket) SetWithMeta(k string, flags int, exp int, v interface{}) (*MutationToken, error) {
+	return b.WriteWithMT(k, flags, exp, v, 0)
+}
+
+// SetRaw sets a value in this bucket without JSON encoding it.
+func (b *Bucket) SetRaw(k string, exp int, v []byte) error {
+	return b.Write(k, 0, exp, v, Raw)
+}
+
+// Add adds a value to this bucket; like Set except that nothing
+// happens if the key exists.  The value will be serialized into a
+// JSON document.
+func (b *Bucket) Add(k string, exp int, v interface{}) (added bool, err error) {
+	err = b.Write(k, 0, exp, v, AddOnly)
+	if err == ErrKeyExists {
+		return false, nil
+	}
+	return (err == nil), err
+}
+
+// AddRaw adds a value to this bucket; like SetRaw except that nothing
+// happens if the key exists.  The value will be stored as raw bytes.
+func (b *Bucket) AddRaw(k string, exp int, v []byte) (added bool, err error) {
+	err = b.Write(k, 0, exp, v, AddOnly|Raw)
+	if err == ErrKeyExists {
+		return false, nil
+	}
+	return (err == nil), err
+}
+
+// Add adds a value to this bucket; like Set except that nothing
+// happens if the key exists.  The value will be serialized into a
+// JSON document.
+func (b *Bucket) AddWithMT(k string, exp int, v interface{}) (added bool, mt *MutationToken, err error) {
+	mt, err = b.WriteWithMT(k, 0, exp, v, AddOnly)
+	if err == ErrKeyExists {
+		return false, mt, nil
+	}
+	return (err == nil), mt, err
+}
+
+// AddRaw adds a value to this bucket; like SetRaw except that nothing
+// happens if the key exists.  The value will be stored as raw bytes.
+func (b *Bucket) AddRawWithMT(k string, exp int, v []byte) (added bool, mt *MutationToken, err error) {
+	mt, err = b.WriteWithMT(k, 0, exp, v, AddOnly|Raw)
+	if err == ErrKeyExists {
+		return false, mt, nil
+	}
+	return (err == nil), mt, err
+}
+
+// Append appends raw data to an existing item.
+func (b *Bucket) Append(k string, data []byte) error {
+	return b.Write(k, 0, 0, data, Append|Raw)
+}
+
+// Get a value straight from Memcached
+func (b *Bucket) GetsMC(key string, reqDeadline time.Time) (*gomemcached.MCResponse, error) {
+	var err error
+	var response *gomemcached.MCResponse
+
+	if key == "" {
+		return nil, nil
+	}
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("GetsMC", key, t, err) }(time.Now())
+	}
+
+	err = b.Do2(key, func(mc *memcached.Client, vb uint16) error {
+		var err1 error
+
+		mc.SetDeadline(getDeadline(reqDeadline, DefaultTimeout))
+		response, err1 = mc.Get(vb, key)
+		mc.SetDeadline(noDeadline)
+		if err1 != nil {
+			return err1
+		}
+		return nil
+	}, false)
+	return response, err
+}
+
+// Get a value through the subdoc API
+func (b *Bucket) GetsSubDoc(key string, reqDeadline time.Time, subPaths []string) (*gomemcached.MCResponse, error) {
+	var err error
+	var response *gomemcached.MCResponse
+
+	if key == "" {
+		return nil, nil
+	}
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("GetsSubDoc", key, t, err) }(time.Now())
+	}
+
+	err = b.Do2(key, func(mc *memcached.Client, vb uint16) error {
+		var err1 error
+
+		mc.SetDeadline(getDeadline(reqDeadline, DefaultTimeout))
+		response, err1 = mc.GetSubdoc(vb, key, subPaths)
+		mc.SetDeadline(noDeadline)
+		if err1 != nil {
+			return err1
+		}
+		return nil
+	}, false)
+	return response, err
+}
+
+// GetsRaw gets a raw value from this bucket including its CAS
+// counter and flags.
+func (b *Bucket) GetsRaw(k string) (data []byte, flags int,
+	cas uint64, err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("GetsRaw", k, t, err) }(time.Now())
+	}
+
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err := mc.Get(vb, k)
+		if err != nil {
+			return err
+		}
+		cas = res.Cas
+		if len(res.Extras) >= 4 {
+			flags = int(binary.BigEndian.Uint32(res.Extras))
+		}
+		data = res.Body
+		return nil
+	})
+	return
+}
+
+// Gets gets a value from this bucket, including its CAS counter.  The
+// value is expected to be a JSON stream and will be deserialized into
+// rv.
+func (b *Bucket) Gets(k string, rv interface{}, caso *uint64) error {
+	data, _, cas, err := b.GetsRaw(k)
+	if err != nil {
+		return err
+	}
+	if caso != nil {
+		*caso = cas
+	}
+	return json.Unmarshal(data, rv)
+}
+
+// Get a value from this bucket.
+// The value is expected to be a JSON stream and will be deserialized
+// into rv.
+func (b *Bucket) Get(k string, rv interface{}) error {
+	return b.Gets(k, rv, nil)
+}
+
+// GetRaw gets a raw value from this bucket.  No marshaling is performed.
+func (b *Bucket) GetRaw(k string) ([]byte, error) {
+	d, _, _, err := b.GetsRaw(k)
+	return d, err
+}
+
+// GetAndTouchRaw gets a raw value from this bucket including its CAS
+// counter and flags, and updates the expiry on the doc.
+func (b *Bucket) GetAndTouchRaw(k string, exp int) (data []byte,
+	cas uint64, err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("GetsRaw", k, t, err) }(time.Now())
+	}
+
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err := mc.GetAndTouch(vb, k, exp)
+		if err != nil {
+			return err
+		}
+		cas = res.Cas
+		data = res.Body
+		return nil
+	})
+	return data, cas, err
+}
+
+// GetMeta returns the meta values for a key
+func (b *Bucket) GetMeta(k string, flags *int, expiry *int, cas *uint64, seqNo *uint64) (err error) {
+
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("GetsMeta", k, t, err) }(time.Now())
+	}
+
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err := mc.GetMeta(vb, k)
+		if err != nil {
+			return err
+		}
+
+		*cas = res.Cas
+		if len(res.Extras) >= 8 {
+			*flags = int(binary.BigEndian.Uint32(res.Extras[4:]))
+		}
+
+		if len(res.Extras) >= 12 {
+			*expiry = int(binary.BigEndian.Uint32(res.Extras[8:]))
+		}
+
+		if len(res.Extras) >= 20 {
+			*seqNo = uint64(binary.BigEndian.Uint64(res.Extras[12:]))
+		}
+
+		return nil
+	})
+
+	return err
+}
+
+// Delete a key from this bucket.
+func (b *Bucket) Delete(k string) error {
+	return b.Write(k, 0, 0, nil, Raw)
+}
+
+// Incr increments the value at a given key by amt and defaults to def if no value present.
+func (b *Bucket) Incr(k string, amt, def uint64, exp int) (val uint64, err error) {
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("Incr", k, t, err) }(time.Now())
+	}
+
+	var rv uint64
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err := mc.Incr(vb, k, amt, def, exp)
+		if err != nil {
+			return err
+		}
+		rv = res
+		return nil
+	})
+	return rv, err
+}
+
+// Decr decrements the value at a given key by amt and defaults to def if no value present
+func (b *Bucket) Decr(k string, amt, def uint64, exp int) (val uint64, err error) {
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("Decr", k, t, err) }(time.Now())
+	}
+
+	var rv uint64
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		res, err := mc.Decr(vb, k, amt, def, exp)
+		if err != nil {
+			return err
+		}
+		rv = res
+		return nil
+	})
+	return rv, err
+}
+
+// Wrapper around memcached.CASNext()
+func (b *Bucket) casNext(k string, exp int, state *memcached.CASState) bool {
+	if ClientOpCallback != nil {
+		defer func(t time.Time) {
+			ClientOpCallback("casNext", k, t, state.Err)
+		}(time.Now())
+	}
+
+	keepGoing := false
+	state.Err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		keepGoing = mc.CASNext(vb, k, exp, state)
+		return state.Err
+	})
+	return keepGoing && state.Err == nil
+}
+
+// An UpdateFunc is a callback function to update a document
+type UpdateFunc func(current []byte) (updated []byte, err error)
+
+// Return this as the error from an UpdateFunc to cancel the Update
+// operation.
+const UpdateCancel = memcached.CASQuit
+
+// Update performs a Safe update of a document, avoiding conflicts by
+// using CAS.
+//
+// The callback function will be invoked with the current raw document
+// contents (or nil if the document doesn't exist); it should return
+// the updated raw contents (or nil to delete.)  If it decides not to
+// change anything it can return UpdateCancel as the error.
+//
+// If another writer modifies the document between the get and the
+// set, the callback will be invoked again with the newer value.
+func (b *Bucket) Update(k string, exp int, callback UpdateFunc) error {
+	_, err := b.update(k, exp, callback)
+	return err
+}
+
+// internal version of Update that returns a CAS value
+func (b *Bucket) update(k string, exp int, callback UpdateFunc) (newCas uint64, err error) {
+	var state memcached.CASState
+	for b.casNext(k, exp, &state) {
+		var err error
+		if state.Value, err = callback(state.Value); err != nil {
+			return 0, err
+		}
+	}
+	return state.Cas, state.Err
+}
+
+// A WriteUpdateFunc is a callback function to update a document
+type WriteUpdateFunc func(current []byte) (updated []byte, opt WriteOptions, err error)
+
+// WriteUpdate performs a Safe update of a document, avoiding
+// conflicts by using CAS.  WriteUpdate is like Update, except that
+// the callback can return a set of WriteOptions, of which Persist and
+// Indexable are recognized: these cause the call to wait until the
+// document update has been persisted to disk and/or become available
+// to index.
+func (b *Bucket) WriteUpdate(k string, exp int, callback WriteUpdateFunc) error {
+	var writeOpts WriteOptions
+	var deletion bool
+	// Wrap the callback in an UpdateFunc we can pass to Update:
+	updateCallback := func(current []byte) (updated []byte, err error) {
+		update, opt, err := callback(current)
+		writeOpts = opt
+		deletion = (update == nil)
+		return update, err
+	}
+	cas, err := b.update(k, exp, updateCallback)
+	if err != nil {
+		return err
+	}
+	// If callback asked, wait for persistence or indexability:
+	if writeOpts&(Persist|Indexable) != 0 {
+		err = b.WaitForPersistence(k, cas, deletion)
+	}
+	return err
+}
+
+// Observe observes the current state of a document.
+func (b *Bucket) Observe(k string) (result memcached.ObserveResult, err error) {
+	if ClientOpCallback != nil {
+		defer func(t time.Time) { ClientOpCallback("Observe", k, t, err) }(time.Now())
+	}
+
+	err = b.Do(k, func(mc *memcached.Client, vb uint16) error {
+		result, err = mc.Observe(vb, k)
+		return err
+	})
+	return
+}
+
+// Returned from WaitForPersistence (or Write, if the Persistent or Indexable flag is used)
+// if the value has been overwritten by another before being persisted.
+var ErrOverwritten = errors.New("overwritten")
+
+// Returned from WaitForPersistence (or Write, if the Persistent or Indexable flag is used)
+// if the value hasn't been persisted by the timeout interval
+var ErrTimeout = errors.New("timeout")
+
+// WaitForPersistence waits for an item to be considered durable.
+//
+// Besides transport errors, ErrOverwritten may be returned if the
+// item is overwritten before it reaches durability.  ErrTimeout may
+// occur if the item isn't found durable in a reasonable amount of
+// time.
+func (b *Bucket) WaitForPersistence(k string, cas uint64, deletion bool) error {
+	timeout := 10 * time.Second
+	sleepDelay := 5 * time.Millisecond
+	start := time.Now()
+	for {
+		time.Sleep(sleepDelay)
+		sleepDelay += sleepDelay / 2 // multiply delay by 1.5 every time
+
+		result, err := b.Observe(k)
+		if err != nil {
+			return err
+		}
+		if persisted, overwritten := result.CheckPersistence(cas, deletion); overwritten {
+			return ErrOverwritten
+		} else if persisted {
+			return nil
+		}
+
+		if result.PersistenceTime > 0 {
+			timeout = 2 * result.PersistenceTime
+		}
+		if time.Since(start) >= timeout-sleepDelay {
+			return ErrTimeout
+		}
+	}
+}
+
+var _STRING_MCRESPONSE_POOL = gomemcached.NewStringMCResponsePool(16)
+
+type stringPool struct {
+	pool *sync.Pool
+	size int
+}
+
+func newStringPool(size int) *stringPool {
+	rv := &stringPool{
+		pool: &sync.Pool{
+			New: func() interface{} {
+				return make([]string, 0, size)
+			},
+		},
+		size: size,
+	}
+
+	return rv
+}
+
+func (this *stringPool) Get() []string {
+	return this.pool.Get().([]string)
+}
+
+func (this *stringPool) Put(s []string) {
+	if s == nil || cap(s) < this.size || cap(s) > 2*this.size {
+		return
+	}
+
+	this.pool.Put(s[0:0])
+}
+
+var _STRING_POOL = newStringPool(16)
+
+type vbStringPool struct {
+	pool    *sync.Pool
+	strPool *stringPool
+}
+
+func newVBStringPool(size int, sp *stringPool) *vbStringPool {
+	rv := &vbStringPool{
+		pool: &sync.Pool{
+			New: func() interface{} {
+				return make(map[uint16][]string, size)
+			},
+		},
+		strPool: sp,
+	}
+
+	return rv
+}
+
+func (this *vbStringPool) Get() map[uint16][]string {
+	return this.pool.Get().(map[uint16][]string)
+}
+
+func (this *vbStringPool) Put(s map[uint16][]string) {
+	if s == nil {
+		return
+	}
+
+	for k, v := range s {
+		delete(s, k)
+		this.strPool.Put(v)
+	}
+
+	this.pool.Put(s)
+}
+
+var _VB_STRING_POOL = newVBStringPool(16, _STRING_POOL)
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/conn_pool.go b/vendor/github.com/couchbaselabs/go-couchbase/conn_pool.go
new file mode 100644
index 0000000000..babd3adb6a
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/conn_pool.go
@@ -0,0 +1,387 @@
+package couchbase
+
+import (
+	"errors"
+	"sync/atomic"
+	"time"
+
+	"github.com/couchbase/gomemcached"
+	"github.com/couchbase/gomemcached/client"
+	"github.com/couchbase/goutils/logging"
+)
+
+// GenericMcdAuthHandler is a kind of AuthHandler that performs
+// special auth exchange (like non-standard auth, possibly followed by
+// select-bucket).
+type GenericMcdAuthHandler interface {
+	AuthHandler
+	AuthenticateMemcachedConn(host string, conn *memcached.Client) error
+}
+
+// Error raised when a connection can't be retrieved from a pool.
+var TimeoutError = errors.New("timeout waiting to build connection")
+var errClosedPool = errors.New("the connection pool is closed")
+var errNoPool = errors.New("no connection pool")
+
+// Default timeout for retrieving a connection from the pool.
+var ConnPoolTimeout = time.Hour * 24 * 30
+
+// overflow connection closer cycle time
+var ConnCloserInterval = time.Second * 30
+
+// ConnPoolAvailWaitTime is the amount of time to wait for an existing
+// connection from the pool before considering the creation of a new
+// one.
+var ConnPoolAvailWaitTime = time.Millisecond
+
+type connectionPool struct {
+	host        string
+	mkConn      func(host string, ah AuthHandler) (*memcached.Client, error)
+	auth        AuthHandler
+	connections chan *memcached.Client
+	createsem   chan bool
+	bailOut     chan bool
+	poolSize    int
+	connCount   uint64
+	inUse       bool
+}
+
+func newConnectionPool(host string, ah AuthHandler, closer bool, poolSize, poolOverflow int) *connectionPool {
+	connSize := poolSize
+	if closer {
+		connSize += poolOverflow
+	}
+	rv := &connectionPool{
+		host:        host,
+		connections: make(chan *memcached.Client, connSize),
+		createsem:   make(chan bool, poolSize+poolOverflow),
+		mkConn:      defaultMkConn,
+		auth:        ah,
+		poolSize:    poolSize,
+	}
+	if closer {
+		rv.bailOut = make(chan bool, 1)
+		go rv.connCloser()
+	}
+	return rv
+}
+
+// ConnPoolTimeout is notified whenever connections are acquired from a pool.
+var ConnPoolCallback func(host string, source string, start time.Time, err error)
+
+func defaultMkConn(host string, ah AuthHandler) (*memcached.Client, error) {
+	var features memcached.Features
+
+	conn, err := memcached.Connect("tcp", host)
+	if err != nil {
+		return nil, err
+	}
+
+	if TCPKeepalive == true {
+		conn.SetKeepAliveOptions(time.Duration(TCPKeepaliveInterval) * time.Second)
+	}
+
+	if EnableMutationToken == true {
+		features = append(features, memcached.FeatureMutationToken)
+	}
+	if EnableDataType == true {
+		features = append(features, memcached.FeatureDataType)
+	}
+
+	if EnableXattr == true {
+		features = append(features, memcached.FeatureXattr)
+	}
+
+	if len(features) > 0 {
+		if DefaultTimeout > 0 {
+			conn.SetDeadline(getDeadline(noDeadline, DefaultTimeout))
+		}
+
+		res, err := conn.EnableFeatures(features)
+
+		if DefaultTimeout > 0 {
+			conn.SetDeadline(noDeadline)
+		}
+
+		if err != nil && isTimeoutError(err) {
+			conn.Close()
+			return nil, err
+		}
+
+		if err != nil || res.Status != gomemcached.SUCCESS {
+			logging.Warnf("Unable to enable features %v", err)
+		}
+	}
+
+	if gah, ok := ah.(GenericMcdAuthHandler); ok {
+		err = gah.AuthenticateMemcachedConn(host, conn)
+		if err != nil {
+			conn.Close()
+			return nil, err
+		}
+		return conn, nil
+	}
+	name, pass, bucket := ah.GetCredentials()
+	if name != "default" {
+		_, err = conn.Auth(name, pass)
+		if err != nil {
+			conn.Close()
+			return nil, err
+		}
+		// Select bucket (Required for cb_auth creds)
+		// Required when doing auth with _admin credentials
+		if bucket != "" && bucket != name {
+			_, err = conn.SelectBucket(bucket)
+			if err != nil {
+				conn.Close()
+				return nil, err
+			}
+		}
+	}
+	return conn, nil
+}
+
+func (cp *connectionPool) Close() (err error) {
+	defer func() {
+		if recover() != nil {
+			err = errors.New("connectionPool.Close error")
+		}
+	}()
+	if cp.bailOut != nil {
+
+		// defensively, we won't wait if the channel is full
+		select {
+		case cp.bailOut <- false:
+		default:
+		}
+	}
+	close(cp.connections)
+	for c := range cp.connections {
+		c.Close()
+	}
+	return
+}
+
+func (cp *connectionPool) Node() string {
+	return cp.host
+}
+
+func (cp *connectionPool) GetWithTimeout(d time.Duration) (rv *memcached.Client, err error) {
+	if cp == nil {
+		return nil, errNoPool
+	}
+
+	path := ""
+
+	if ConnPoolCallback != nil {
+		defer func(path *string, start time.Time) {
+			ConnPoolCallback(cp.host, *path, start, err)
+		}(&path, time.Now())
+	}
+
+	path = "short-circuit"
+
+	// short-circuit available connetions.
+	select {
+	case rv, isopen := <-cp.connections:
+		if !isopen {
+			return nil, errClosedPool
+		}
+		atomic.AddUint64(&cp.connCount, 1)
+		return rv, nil
+	default:
+	}
+
+	t := time.NewTimer(ConnPoolAvailWaitTime)
+	defer t.Stop()
+
+	// Try to grab an available connection within 1ms
+	select {
+	case rv, isopen := <-cp.connections:
+		path = "avail1"
+		if !isopen {
+			return nil, errClosedPool
+		}
+		atomic.AddUint64(&cp.connCount, 1)
+		return rv, nil
+	case <-t.C:
+		// No connection came around in time, let's see
+		// whether we can get one or build a new one first.
+		t.Reset(d) // Reuse the timer for the full timeout.
+		select {
+		case rv, isopen := <-cp.connections:
+			path = "avail2"
+			if !isopen {
+				return nil, errClosedPool
+			}
+			atomic.AddUint64(&cp.connCount, 1)
+			return rv, nil
+		case cp.createsem <- true:
+			path = "create"
+			// Build a connection if we can't get a real one.
+			// This can potentially be an overflow connection, or
+			// a pooled connection.
+			rv, err := cp.mkConn(cp.host, cp.auth)
+			if err != nil {
+				// On error, release our create hold
+				<-cp.createsem
+			} else {
+				atomic.AddUint64(&cp.connCount, 1)
+			}
+			return rv, err
+		case <-t.C:
+			return nil, ErrTimeout
+		}
+	}
+}
+
+func (cp *connectionPool) Get() (*memcached.Client, error) {
+	return cp.GetWithTimeout(ConnPoolTimeout)
+}
+
+func (cp *connectionPool) Return(c *memcached.Client) {
+	if c == nil {
+		return
+	}
+
+	if cp == nil {
+		c.Close()
+	}
+
+	if c.IsHealthy() {
+		defer func() {
+			if recover() != nil {
+				// This happens when the pool has already been
+				// closed and we're trying to return a
+				// connection to it anyway.  Just close the
+				// connection.
+				c.Close()
+			}
+		}()
+
+		select {
+		case cp.connections <- c:
+		default:
+			<-cp.createsem
+			c.Close()
+		}
+	} else {
+		<-cp.createsem
+		c.Close()
+	}
+}
+
+// give the ability to discard a connection from a pool
+// useful for ditching connections to the wrong node after a rebalance
+func (cp *connectionPool) Discard(c *memcached.Client) {
+	<-cp.createsem
+	c.Close()
+}
+
+// asynchronous connection closer
+func (cp *connectionPool) connCloser() {
+	var connCount uint64
+
+	t := time.NewTimer(ConnCloserInterval)
+	defer t.Stop()
+
+	for {
+		connCount = cp.connCount
+
+		// we don't exist anymore! bail out!
+		select {
+		case <-cp.bailOut:
+			return
+		case <-t.C:
+		}
+		t.Reset(ConnCloserInterval)
+
+		// no overflow connections open or sustained requests for connections
+		// nothing to do until the next cycle
+		if len(cp.connections) <= cp.poolSize ||
+			ConnCloserInterval/ConnPoolAvailWaitTime < time.Duration(cp.connCount-connCount) {
+			continue
+		}
+
+		// close overflow connections now that they are not needed
+		for c := range cp.connections {
+			select {
+			case <-cp.bailOut:
+				return
+			default:
+			}
+
+			// bail out if close did not work out
+			if !cp.connCleanup(c) {
+				return
+			}
+			if len(cp.connections) <= cp.poolSize {
+				break
+			}
+		}
+	}
+}
+
+// close connection with recovery on error
+func (cp *connectionPool) connCleanup(c *memcached.Client) (rv bool) {
+
+	// just in case we are closing a connection after
+	// bailOut has been sent but we haven't yet read it
+	defer func() {
+		if recover() != nil {
+			rv = false
+		}
+	}()
+	rv = true
+
+	c.Close()
+	<-cp.createsem
+	return
+}
+
+func (cp *connectionPool) StartTapFeed(args *memcached.TapArguments) (*memcached.TapFeed, error) {
+	if cp == nil {
+		return nil, errNoPool
+	}
+	mc, err := cp.Get()
+	if err != nil {
+		return nil, err
+	}
+
+	// A connection can't be used after TAP; Dont' count it against the
+	// connection pool capacity
+	<-cp.createsem
+
+	return mc.StartTapFeed(*args)
+}
+
+const DEFAULT_WINDOW_SIZE = 20 * 1024 * 1024 // 20 Mb
+
+func (cp *connectionPool) StartUprFeed(name string, sequence uint32, dcp_buffer_size uint32, data_chan_size int) (*memcached.UprFeed, error) {
+	if cp == nil {
+		return nil, errNoPool
+	}
+	mc, err := cp.Get()
+	if err != nil {
+		return nil, err
+	}
+
+	// A connection can't be used after it has been allocated to UPR;
+	// Dont' count it against the connection pool capacity
+	<-cp.createsem
+
+	uf, err := mc.NewUprFeed()
+	if err != nil {
+		return nil, err
+	}
+
+	if err := uf.UprOpen(name, sequence, dcp_buffer_size); err != nil {
+		return nil, err
+	}
+
+	if err := uf.StartFeedWithConfig(data_chan_size); err != nil {
+		return nil, err
+	}
+
+	return uf, nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/ddocs.go b/vendor/github.com/couchbaselabs/go-couchbase/ddocs.go
new file mode 100644
index 0000000000..f9cc343aa8
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/ddocs.go
@@ -0,0 +1,288 @@
+package couchbase
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"github.com/couchbase/goutils/logging"
+	"io/ioutil"
+	"net/http"
+)
+
+// ViewDefinition represents a single view within a design document.
+type ViewDefinition struct {
+	Map    string `json:"map"`
+	Reduce string `json:"reduce,omitempty"`
+}
+
+// DDoc is the document body of a design document specifying a view.
+type DDoc struct {
+	Language string                    `json:"language,omitempty"`
+	Views    map[string]ViewDefinition `json:"views"`
+}
+
+// DDocsResult represents the result from listing the design
+// documents.
+type DDocsResult struct {
+	Rows []struct {
+		DDoc struct {
+			Meta map[string]interface{}
+			JSON DDoc
+		} `json:"doc"`
+	} `json:"rows"`
+}
+
+// GetDDocs lists all design documents
+func (b *Bucket) GetDDocs() (DDocsResult, error) {
+	var ddocsResult DDocsResult
+	b.RLock()
+	pool := b.pool
+	uri := b.DDocs.URI
+	b.RUnlock()
+
+	// MB-23555 ephemeral buckets have no ddocs
+	if uri == "" {
+		return DDocsResult{}, nil
+	}
+
+	err := pool.client.parseURLResponse(uri, &ddocsResult)
+	if err != nil {
+		return DDocsResult{}, err
+	}
+	return ddocsResult, nil
+}
+
+func (b *Bucket) GetDDocWithRetry(docname string, into interface{}) error {
+	ddocURI := fmt.Sprintf("/%s/_design/%s", b.GetName(), docname)
+	err := b.parseAPIResponse(ddocURI, &into)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (b *Bucket) GetDDocsWithRetry() (DDocsResult, error) {
+	var ddocsResult DDocsResult
+	b.RLock()
+	uri := b.DDocs.URI
+	b.RUnlock()
+
+	// MB-23555 ephemeral buckets have no ddocs
+	if uri == "" {
+		return DDocsResult{}, nil
+	}
+
+	err := b.parseURLResponse(uri, &ddocsResult)
+	if err != nil {
+		return DDocsResult{}, err
+	}
+	return ddocsResult, nil
+}
+
+func (b *Bucket) ddocURL(docname string) (string, error) {
+	u, err := b.randomBaseURL()
+	if err != nil {
+		return "", err
+	}
+	u.Path = fmt.Sprintf("/%s/_design/%s", b.GetName(), docname)
+	return u.String(), nil
+}
+
+func (b *Bucket) ddocURLNext(nodeId int, docname string) (string, int, error) {
+	u, selected, err := b.randomNextURL(nodeId)
+	if err != nil {
+		return "", -1, err
+	}
+	u.Path = fmt.Sprintf("/%s/_design/%s", b.GetName(), docname)
+	return u.String(), selected, nil
+}
+
+const ABS_MAX_RETRIES = 10
+const ABS_MIN_RETRIES = 3
+
+func (b *Bucket) getMaxRetries() (int, error) {
+
+	maxRetries := len(b.Nodes())
+
+	if maxRetries == 0 {
+		return 0, fmt.Errorf("No available Couch rest URLs")
+	}
+
+	if maxRetries > ABS_MAX_RETRIES {
+		maxRetries = ABS_MAX_RETRIES
+	} else if maxRetries < ABS_MIN_RETRIES {
+		maxRetries = ABS_MIN_RETRIES
+	}
+
+	return maxRetries, nil
+}
+
+// PutDDoc installs a design document.
+func (b *Bucket) PutDDoc(docname string, value interface{}) error {
+
+	var Err error
+
+	maxRetries, err := b.getMaxRetries()
+	if err != nil {
+		return err
+	}
+
+	lastNode := START_NODE_ID
+
+	for retryCount := 0; retryCount < maxRetries; retryCount++ {
+
+		Err = nil
+
+		ddocU, selectedNode, err := b.ddocURLNext(lastNode, docname)
+		if err != nil {
+			return err
+		}
+
+		lastNode = selectedNode
+
+		logging.Infof(" Trying with selected node %d", selectedNode)
+		j, err := json.Marshal(value)
+		if err != nil {
+			return err
+		}
+
+		req, err := http.NewRequest("PUT", ddocU, bytes.NewReader(j))
+		if err != nil {
+			return err
+		}
+		req.Header.Set("Content-Type", "application/json")
+		err = maybeAddAuth(req, b.authHandler(false /* bucket not yet locked */))
+		if err != nil {
+			return err
+		}
+
+		res, err := doHTTPRequest(req)
+		if err != nil {
+			return err
+		}
+
+		if res.StatusCode != 201 {
+			body, _ := ioutil.ReadAll(res.Body)
+			Err = fmt.Errorf("error installing view: %v / %s",
+				res.Status, body)
+			logging.Errorf(" Error in PutDDOC %v. Retrying...", Err)
+			res.Body.Close()
+			b.Refresh()
+			continue
+		}
+
+		res.Body.Close()
+		break
+	}
+
+	return Err
+}
+
+// GetDDoc retrieves a specific a design doc.
+func (b *Bucket) GetDDoc(docname string, into interface{}) error {
+	var Err error
+	var res *http.Response
+
+	maxRetries, err := b.getMaxRetries()
+	if err != nil {
+		return err
+	}
+
+	lastNode := START_NODE_ID
+	for retryCount := 0; retryCount < maxRetries; retryCount++ {
+
+		Err = nil
+		ddocU, selectedNode, err := b.ddocURLNext(lastNode, docname)
+		if err != nil {
+			return err
+		}
+
+		lastNode = selectedNode
+		logging.Infof(" Trying with selected node %d", selectedNode)
+
+		req, err := http.NewRequest("GET", ddocU, nil)
+		if err != nil {
+			return err
+		}
+		req.Header.Set("Content-Type", "application/json")
+		err = maybeAddAuth(req, b.authHandler(false /* bucket not yet locked */))
+		if err != nil {
+			return err
+		}
+
+		res, err = doHTTPRequest(req)
+		if err != nil {
+			return err
+		}
+		if res.StatusCode != 200 {
+			body, _ := ioutil.ReadAll(res.Body)
+			Err = fmt.Errorf("error reading view: %v / %s",
+				res.Status, body)
+			logging.Errorf(" Error in GetDDOC %v Retrying...", Err)
+			b.Refresh()
+			res.Body.Close()
+			continue
+		}
+		defer res.Body.Close()
+		break
+	}
+
+	if Err != nil {
+		return Err
+	}
+
+	d := json.NewDecoder(res.Body)
+	return d.Decode(into)
+}
+
+// DeleteDDoc removes a design document.
+func (b *Bucket) DeleteDDoc(docname string) error {
+
+	var Err error
+
+	maxRetries, err := b.getMaxRetries()
+	if err != nil {
+		return err
+	}
+
+	lastNode := START_NODE_ID
+
+	for retryCount := 0; retryCount < maxRetries; retryCount++ {
+
+		Err = nil
+		ddocU, selectedNode, err := b.ddocURLNext(lastNode, docname)
+		if err != nil {
+			return err
+		}
+
+		lastNode = selectedNode
+		logging.Infof(" Trying with selected node %d", selectedNode)
+
+		req, err := http.NewRequest("DELETE", ddocU, nil)
+		if err != nil {
+			return err
+		}
+		req.Header.Set("Content-Type", "application/json")
+		err = maybeAddAuth(req, b.authHandler(false /* bucket not already locked */))
+		if err != nil {
+			return err
+		}
+
+		res, err := doHTTPRequest(req)
+		if err != nil {
+			return err
+		}
+		if res.StatusCode != 200 {
+			body, _ := ioutil.ReadAll(res.Body)
+			Err = fmt.Errorf("error deleting view : %v / %s", res.Status, body)
+			logging.Errorf(" Error in DeleteDDOC %v. Retrying ... ", Err)
+			b.Refresh()
+			res.Body.Close()
+			continue
+		}
+
+		res.Body.Close()
+		break
+	}
+	return Err
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/observe.go b/vendor/github.com/couchbaselabs/go-couchbase/observe.go
new file mode 100644
index 0000000000..6e746f5a16
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/observe.go
@@ -0,0 +1,300 @@
+package couchbase
+
+import (
+	"fmt"
+	"github.com/couchbase/goutils/logging"
+	"sync"
+)
+
+type PersistTo uint8
+
+const (
+	PersistNone   = PersistTo(0x00)
+	PersistMaster = PersistTo(0x01)
+	PersistOne    = PersistTo(0x02)
+	PersistTwo    = PersistTo(0x03)
+	PersistThree  = PersistTo(0x04)
+	PersistFour   = PersistTo(0x05)
+)
+
+type ObserveTo uint8
+
+const (
+	ObserveNone           = ObserveTo(0x00)
+	ObserveReplicateOne   = ObserveTo(0x01)
+	ObserveReplicateTwo   = ObserveTo(0x02)
+	ObserveReplicateThree = ObserveTo(0x03)
+	ObserveReplicateFour  = ObserveTo(0x04)
+)
+
+type JobType uint8
+
+const (
+	OBSERVE = JobType(0x00)
+	PERSIST = JobType(0x01)
+)
+
+type ObservePersistJob struct {
+	vb                 uint16
+	vbuuid             uint64
+	hostname           string
+	jobType            JobType
+	failover           uint8
+	lastPersistedSeqNo uint64
+	currentSeqNo       uint64
+	resultChan         chan *ObservePersistJob
+	errorChan          chan *OPErrResponse
+}
+
+type OPErrResponse struct {
+	vb     uint16
+	vbuuid uint64
+	err    error
+	job    *ObservePersistJob
+}
+
+var ObservePersistPool = NewPool(1024)
+var OPJobChan = make(chan *ObservePersistJob, 1024)
+var OPJobDone = make(chan bool)
+
+var wg sync.WaitGroup
+
+func (b *Bucket) StartOPPollers(maxWorkers int) {
+
+	for i := 0; i < maxWorkers; i++ {
+		go b.OPJobPoll()
+		wg.Add(1)
+	}
+	wg.Wait()
+}
+
+func (b *Bucket) SetObserveAndPersist(nPersist PersistTo, nObserve ObserveTo) (err error) {
+
+	numNodes := len(b.Nodes())
+	if int(nPersist) > numNodes || int(nObserve) > numNodes {
+		return fmt.Errorf("Not enough healthy nodes in the cluster")
+	}
+
+	if int(nPersist) > (b.Replicas+1) || int(nObserve) > b.Replicas {
+		return fmt.Errorf("Not enough replicas in the cluster")
+	}
+
+	if EnableMutationToken == false {
+		return fmt.Errorf("Mutation Tokens not enabled ")
+	}
+
+	b.ds = &DurablitySettings{Persist: PersistTo(nPersist), Observe: ObserveTo(nObserve)}
+	return
+}
+
+func (b *Bucket) ObserveAndPersistPoll(vb uint16, vbuuid uint64, seqNo uint64) (err error, failover bool) {
+	b.RLock()
+	ds := b.ds
+	b.RUnlock()
+
+	if ds == nil {
+		return
+	}
+
+	nj := 0 // total number of jobs
+	resultChan := make(chan *ObservePersistJob, 10)
+	errChan := make(chan *OPErrResponse, 10)
+
+	nodes := b.GetNodeList(vb)
+	if int(ds.Observe) > len(nodes) || int(ds.Persist) > len(nodes) {
+		return fmt.Errorf("Not enough healthy nodes in the cluster"), false
+	}
+
+	logging.Infof("Node list %v", nodes)
+
+	if ds.Observe >= ObserveReplicateOne {
+		// create a job for each host
+		for i := ObserveReplicateOne; i < ds.Observe+1; i++ {
+			opJob := ObservePersistPool.Get()
+			opJob.vb = vb
+			opJob.vbuuid = vbuuid
+			opJob.jobType = OBSERVE
+			opJob.hostname = nodes[i]
+			opJob.resultChan = resultChan
+			opJob.errorChan = errChan
+
+			OPJobChan <- opJob
+			nj++
+
+		}
+	}
+
+	if ds.Persist >= PersistMaster {
+		for i := PersistMaster; i < ds.Persist+1; i++ {
+			opJob := ObservePersistPool.Get()
+			opJob.vb = vb
+			opJob.vbuuid = vbuuid
+			opJob.jobType = PERSIST
+			opJob.hostname = nodes[i]
+			opJob.resultChan = resultChan
+			opJob.errorChan = errChan
+
+			OPJobChan <- opJob
+			nj++
+
+		}
+	}
+
+	ok := true
+	for ok {
+		select {
+		case res := <-resultChan:
+			jobDone := false
+			if res.failover == 0 {
+				// no failover
+				if res.jobType == PERSIST {
+					if res.lastPersistedSeqNo >= seqNo {
+						jobDone = true
+					}
+
+				} else {
+					if res.currentSeqNo >= seqNo {
+						jobDone = true
+					}
+				}
+
+				if jobDone == true {
+					nj--
+					ObservePersistPool.Put(res)
+				} else {
+					// requeue this job
+					OPJobChan <- res
+				}
+
+			} else {
+				// Not currently handling failover scenarios TODO
+				nj--
+				ObservePersistPool.Put(res)
+				failover = true
+			}
+
+			if nj == 0 {
+				// done with all the jobs
+				ok = false
+				close(resultChan)
+				close(errChan)
+			}
+
+		case Err := <-errChan:
+			logging.Errorf("Error in Observe/Persist %v", Err.err)
+			err = fmt.Errorf("Error in Observe/Persist job %v", Err.err)
+			nj--
+			ObservePersistPool.Put(Err.job)
+			if nj == 0 {
+				close(resultChan)
+				close(errChan)
+				ok = false
+			}
+		}
+	}
+
+	return
+}
+
+func (b *Bucket) OPJobPoll() {
+
+	ok := true
+	for ok == true {
+		select {
+		case job := <-OPJobChan:
+			pool := b.getConnPoolByHost(job.hostname, false /* bucket not already locked */)
+			if pool == nil {
+				errRes := &OPErrResponse{vb: job.vb, vbuuid: job.vbuuid}
+				errRes.err = fmt.Errorf("Pool not found for host %v", job.hostname)
+				errRes.job = job
+				job.errorChan <- errRes
+				continue
+			}
+			conn, err := pool.Get()
+			if err != nil {
+				errRes := &OPErrResponse{vb: job.vb, vbuuid: job.vbuuid}
+				errRes.err = fmt.Errorf("Unable to get connection from pool %v", err)
+				errRes.job = job
+				job.errorChan <- errRes
+				continue
+			}
+
+			res, err := conn.ObserveSeq(job.vb, job.vbuuid)
+			if err != nil {
+				errRes := &OPErrResponse{vb: job.vb, vbuuid: job.vbuuid}
+				errRes.err = fmt.Errorf("Command failed %v", err)
+				errRes.job = job
+				job.errorChan <- errRes
+				continue
+
+			}
+			pool.Return(conn)
+			job.lastPersistedSeqNo = res.LastPersistedSeqNo
+			job.currentSeqNo = res.CurrentSeqNo
+			job.failover = res.Failover
+
+			job.resultChan <- job
+		case <-OPJobDone:
+			logging.Infof("Observe Persist Poller exitting")
+			ok = false
+		}
+	}
+	wg.Done()
+}
+
+func (b *Bucket) GetNodeList(vb uint16) []string {
+
+	vbm := b.VBServerMap()
+	if len(vbm.VBucketMap) < int(vb) {
+		logging.Infof("vbmap smaller than vblist")
+		return nil
+	}
+
+	nodes := make([]string, len(vbm.VBucketMap[vb]))
+	for i := 0; i < len(vbm.VBucketMap[vb]); i++ {
+		n := vbm.VBucketMap[vb][i]
+		if n < 0 {
+			continue
+		}
+
+		node := b.getMasterNode(n)
+		if len(node) > 1 {
+			nodes[i] = node
+		}
+		continue
+
+	}
+	return nodes
+}
+
+//pool of ObservePersist Jobs
+type OPpool struct {
+	pool chan *ObservePersistJob
+}
+
+// NewPool creates a new pool of jobs
+func NewPool(max int) *OPpool {
+	return &OPpool{
+		pool: make(chan *ObservePersistJob, max),
+	}
+}
+
+// Borrow a Client from the pool.
+func (p *OPpool) Get() *ObservePersistJob {
+	var o *ObservePersistJob
+	select {
+	case o = <-p.pool:
+	default:
+		o = &ObservePersistJob{}
+	}
+	return o
+}
+
+// Return returns a Client to the pool.
+func (p *OPpool) Put(o *ObservePersistJob) {
+	select {
+	case p.pool <- o:
+	default:
+		// let it go, let it go...
+	}
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/pools.go b/vendor/github.com/couchbaselabs/go-couchbase/pools.go
new file mode 100644
index 0000000000..5f3ff8c495
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/pools.go
@@ -0,0 +1,1282 @@
+package couchbase
+
+import (
+	"bufio"
+	"bytes"
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/base64"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net/http"
+	"net/url"
+	"runtime"
+	"sort"
+	"strings"
+	"sync"
+	"unsafe"
+
+	"github.com/couchbase/goutils/logging"
+
+	"github.com/couchbase/gomemcached"        // package name is 'gomemcached'
+	"github.com/couchbase/gomemcached/client" // package name is 'memcached'
+)
+
+// HTTPClient to use for REST and view operations.
+var MaxIdleConnsPerHost = 256
+var HTTPTransport = &http.Transport{MaxIdleConnsPerHost: MaxIdleConnsPerHost}
+var HTTPClient = &http.Client{Transport: HTTPTransport}
+
+// PoolSize is the size of each connection pool (per host).
+var PoolSize = 64
+
+// PoolOverflow is the number of overflow connections allowed in a
+// pool.
+var PoolOverflow = 16
+
+// AsynchronousCloser turns on asynchronous closing for overflow connections
+var AsynchronousCloser = false
+
+// TCP KeepAlive enabled/disabled
+var TCPKeepalive = false
+
+// Enable MutationToken
+var EnableMutationToken = false
+
+// Enable Data Type response
+var EnableDataType = false
+
+// Enable Xattr
+var EnableXattr = false
+
+// TCP keepalive interval in seconds. Default 30 minutes
+var TCPKeepaliveInterval = 30 * 60
+
+// Used to decide whether to skip verification of certificates when
+// connecting to an ssl port.
+var skipVerify = true
+var certFile = ""
+var keyFile = ""
+var rootFile = ""
+
+func SetSkipVerify(skip bool) {
+	skipVerify = skip
+}
+
+func SetCertFile(cert string) {
+	certFile = cert
+}
+
+func SetKeyFile(cert string) {
+	keyFile = cert
+}
+
+func SetRootFile(cert string) {
+	rootFile = cert
+}
+
+// Allow applications to speciify the Poolsize and Overflow
+func SetConnectionPoolParams(size, overflow int) {
+
+	if size > 0 {
+		PoolSize = size
+	}
+
+	if overflow > 0 {
+		PoolOverflow = overflow
+	}
+}
+
+// Turn off overflow connections
+func DisableOverflowConnections() {
+	PoolOverflow = 0
+}
+
+// Toggle asynchronous overflow closer
+func EnableAsynchronousCloser(closer bool) {
+	AsynchronousCloser = closer
+}
+
+// Allow TCP keepalive parameters to be set by the application
+func SetTcpKeepalive(enabled bool, interval int) {
+
+	TCPKeepalive = enabled
+
+	if interval > 0 {
+		TCPKeepaliveInterval = interval
+	}
+}
+
+// AuthHandler is a callback that gets the auth username and password
+// for the given bucket.
+type AuthHandler interface {
+	GetCredentials() (string, string, string)
+}
+
+// AuthHandler is a callback that gets the auth username and password
+// for the given bucket and sasl for memcached.
+type AuthWithSaslHandler interface {
+	AuthHandler
+	GetSaslCredentials() (string, string)
+}
+
+// MultiBucketAuthHandler is kind of AuthHandler that may perform
+// different auth for different buckets.
+type MultiBucketAuthHandler interface {
+	AuthHandler
+	ForBucket(bucket string) AuthHandler
+}
+
+// HTTPAuthHandler is kind of AuthHandler that performs more general
+// for outgoing http requests than is possible via simple
+// GetCredentials() call (i.e. digest auth or different auth per
+// different destinations).
+type HTTPAuthHandler interface {
+	AuthHandler
+	SetCredsForRequest(req *http.Request) error
+}
+
+// RestPool represents a single pool returned from the pools REST API.
+type RestPool struct {
+	Name         string `json:"name"`
+	StreamingURI string `json:"streamingUri"`
+	URI          string `json:"uri"`
+}
+
+// Pools represents the collection of pools as returned from the REST API.
+type Pools struct {
+	ComponentsVersion     map[string]string `json:"componentsVersion,omitempty"`
+	ImplementationVersion string            `json:"implementationVersion"`
+	IsAdmin               bool              `json:"isAdminCreds"`
+	UUID                  string            `json:"uuid"`
+	Pools                 []RestPool        `json:"pools"`
+}
+
+// A Node is a computer in a cluster running the couchbase software.
+type Node struct {
+	ClusterCompatibility int                `json:"clusterCompatibility"`
+	ClusterMembership    string             `json:"clusterMembership"`
+	CouchAPIBase         string             `json:"couchApiBase"`
+	Hostname             string             `json:"hostname"`
+	InterestingStats     map[string]float64 `json:"interestingStats,omitempty"`
+	MCDMemoryAllocated   float64            `json:"mcdMemoryAllocated"`
+	MCDMemoryReserved    float64            `json:"mcdMemoryReserved"`
+	MemoryFree           float64            `json:"memoryFree"`
+	MemoryTotal          float64            `json:"memoryTotal"`
+	OS                   string             `json:"os"`
+	Ports                map[string]int     `json:"ports"`
+	Services             []string           `json:"services"`
+	Status               string             `json:"status"`
+	Uptime               int                `json:"uptime,string"`
+	Version              string             `json:"version"`
+	ThisNode             bool               `json:"thisNode,omitempty"`
+}
+
+// A Pool of nodes and buckets.
+type Pool struct {
+	BucketMap map[string]Bucket
+	Nodes     []Node
+
+	BucketURL map[string]string `json:"buckets"`
+
+	client Client
+}
+
+// VBucketServerMap is the a mapping of vbuckets to nodes.
+type VBucketServerMap struct {
+	HashAlgorithm string   `json:"hashAlgorithm"`
+	NumReplicas   int      `json:"numReplicas"`
+	ServerList    []string `json:"serverList"`
+	VBucketMap    [][]int  `json:"vBucketMap"`
+}
+
+type DurablitySettings struct {
+	Persist PersistTo
+	Observe ObserveTo
+}
+
+// Bucket is the primary entry point for most data operations.
+// Bucket is a locked data structure. All access to its fields should be done using read or write locking,
+// as appropriate.
+//
+// Some access methods require locking, but rely on the caller to do so. These are appropriate
+// for calls from methods that have already locked the structure. Methods like this
+// take a boolean parameter "bucketLocked".
+type Bucket struct {
+	sync.RWMutex
+	AuthType               string             `json:"authType"`
+	Capabilities           []string           `json:"bucketCapabilities"`
+	CapabilitiesVersion    string             `json:"bucketCapabilitiesVer"`
+	Type                   string             `json:"bucketType"`
+	Name                   string             `json:"name"`
+	NodeLocator            string             `json:"nodeLocator"`
+	Quota                  map[string]float64 `json:"quota,omitempty"`
+	Replicas               int                `json:"replicaNumber"`
+	Password               string             `json:"saslPassword"`
+	URI                    string             `json:"uri"`
+	StreamingURI           string             `json:"streamingUri"`
+	LocalRandomKeyURI      string             `json:"localRandomKeyUri,omitempty"`
+	UUID                   string             `json:"uuid"`
+	ConflictResolutionType string             `json:"conflictResolutionType,omitempty"`
+	DDocs                  struct {
+		URI string `json:"uri"`
+	} `json:"ddocs,omitempty"`
+	BasicStats  map[string]interface{} `json:"basicStats,omitempty"`
+	Controllers map[string]interface{} `json:"controllers,omitempty"`
+
+	// These are used for JSON IO, but isn't used for processing
+	// since it needs to be swapped out safely.
+	VBSMJson  VBucketServerMap `json:"vBucketServerMap"`
+	NodesJSON []Node           `json:"nodes"`
+
+	pool             *Pool
+	connPools        unsafe.Pointer // *[]*connectionPool
+	vBucketServerMap unsafe.Pointer // *VBucketServerMap
+	nodeList         unsafe.Pointer // *[]Node
+	commonSufix      string
+	ah               AuthHandler        // auth handler
+	ds               *DurablitySettings // Durablity Settings for this bucket
+	Scopes           Scopes
+}
+
+// PoolServices is all the bucket-independent services in a pool
+type PoolServices struct {
+	Rev      int            `json:"rev"`
+	NodesExt []NodeServices `json:"nodesExt"`
+}
+
+// NodeServices is all the bucket-independent services running on
+// a node (given by Hostname)
+type NodeServices struct {
+	Services map[string]int `json:"services,omitempty"`
+	Hostname string         `json:"hostname"`
+	ThisNode bool           `json:"thisNode"`
+}
+
+type BucketNotFoundError struct {
+	bucket string
+}
+
+func (e *BucketNotFoundError) Error() string {
+	return fmt.Sprint("No bucket named " + e.bucket)
+}
+
+type BucketAuth struct {
+	name    string
+	saslPwd string
+	bucket  string
+}
+
+func newBucketAuth(name string, pass string, bucket string) *BucketAuth {
+	return &BucketAuth{name: name, saslPwd: pass, bucket: bucket}
+}
+
+func (ba *BucketAuth) GetCredentials() (string, string, string) {
+	return ba.name, ba.saslPwd, ba.bucket
+}
+
+// VBServerMap returns the current VBucketServerMap.
+func (b *Bucket) VBServerMap() *VBucketServerMap {
+	b.RLock()
+	defer b.RUnlock()
+	ret := (*VBucketServerMap)(b.vBucketServerMap)
+	return ret
+}
+
+func (b *Bucket) GetVBmap(addrs []string) (map[string][]uint16, error) {
+	vbmap := b.VBServerMap()
+	servers := vbmap.ServerList
+	if addrs == nil {
+		addrs = vbmap.ServerList
+	}
+
+	m := make(map[string][]uint16)
+	for _, addr := range addrs {
+		m[addr] = make([]uint16, 0)
+	}
+	for vbno, idxs := range vbmap.VBucketMap {
+		if len(idxs) == 0 {
+			return nil, fmt.Errorf("vbmap: No KV node no for vb %d", vbno)
+		} else if idxs[0] < 0 || idxs[0] >= len(servers) {
+			return nil, fmt.Errorf("vbmap: Invalid KV node no %d for vb %d", idxs[0], vbno)
+		}
+		addr := servers[idxs[0]]
+		if _, ok := m[addr]; ok {
+			m[addr] = append(m[addr], uint16(vbno))
+		}
+	}
+	return m, nil
+}
+
+// true if node is not on the bucket VBmap
+func (b *Bucket) checkVBmap(node string) bool {
+	vbmap := b.VBServerMap()
+	servers := vbmap.ServerList
+
+	for _, idxs := range vbmap.VBucketMap {
+		if len(idxs) == 0 {
+			return true
+		} else if idxs[0] < 0 || idxs[0] >= len(servers) {
+			return true
+		}
+		if servers[idxs[0]] == node {
+			return false
+		}
+	}
+	return true
+}
+
+func (b *Bucket) GetName() string {
+	b.RLock()
+	defer b.RUnlock()
+	ret := b.Name
+	return ret
+}
+
+// Nodes returns teh current list of nodes servicing this bucket.
+func (b *Bucket) Nodes() []Node {
+	b.RLock()
+	defer b.RUnlock()
+	ret := *(*[]Node)(b.nodeList)
+	return ret
+}
+
+// return the list of healthy nodes
+func (b *Bucket) HealthyNodes() []Node {
+	nodes := []Node{}
+
+	for _, n := range b.Nodes() {
+		if n.Status == "healthy" && n.CouchAPIBase != "" {
+			nodes = append(nodes, n)
+		}
+		if n.Status != "healthy" { // log non-healthy node
+			logging.Infof("Non-healthy node; node details:")
+			logging.Infof("Hostname=%v, Status=%v, CouchAPIBase=%v, ThisNode=%v", n.Hostname, n.Status, n.CouchAPIBase, n.ThisNode)
+		}
+	}
+
+	return nodes
+}
+
+func (b *Bucket) getConnPools(bucketLocked bool) []*connectionPool {
+	if !bucketLocked {
+		b.RLock()
+		defer b.RUnlock()
+	}
+	if b.connPools != nil {
+		return *(*[]*connectionPool)(b.connPools)
+	} else {
+		return nil
+	}
+}
+
+func (b *Bucket) replaceConnPools(with []*connectionPool) {
+	b.Lock()
+	defer b.Unlock()
+
+	old := b.connPools
+	b.connPools = unsafe.Pointer(&with)
+	if old != nil {
+		for _, pool := range *(*[]*connectionPool)(old) {
+			if pool != nil {
+				pool.Close()
+			}
+		}
+	}
+	return
+}
+
+func (b *Bucket) getConnPool(i int) *connectionPool {
+
+	if i < 0 {
+		return nil
+	}
+
+	p := b.getConnPools(false /* not already locked */)
+	if len(p) > i {
+		return p[i]
+	}
+
+	return nil
+}
+
+func (b *Bucket) getConnPoolByHost(host string, bucketLocked bool) *connectionPool {
+	pools := b.getConnPools(bucketLocked)
+	for _, p := range pools {
+		if p != nil && p.host == host {
+			return p
+		}
+	}
+
+	return nil
+}
+
+// Given a vbucket number, returns a memcached connection to it.
+// The connection must be returned to its pool after use.
+func (b *Bucket) getConnectionToVBucket(vb uint32) (*memcached.Client, *connectionPool, error) {
+	for {
+		vbm := b.VBServerMap()
+		if len(vbm.VBucketMap) < int(vb) {
+			return nil, nil, fmt.Errorf("go-couchbase: vbmap smaller than vbucket list: %v vs. %v",
+				vb, vbm.VBucketMap)
+		}
+		masterId := vbm.VBucketMap[vb][0]
+		if masterId < 0 {
+			return nil, nil, fmt.Errorf("go-couchbase: No master for vbucket %d", vb)
+		}
+		pool := b.getConnPool(masterId)
+		conn, err := pool.Get()
+		if err != errClosedPool {
+			return conn, pool, err
+		}
+		// If conn pool was closed, because another goroutine refreshed the vbucket map, retry...
+	}
+}
+
+// To get random documents, we need to cover all the nodes, so select
+// a connection at random.
+
+func (b *Bucket) getRandomConnection() (*memcached.Client, *connectionPool, error) {
+	for {
+		var currentPool = 0
+		pools := b.getConnPools(false /* not already locked */)
+		if len(pools) == 0 {
+			return nil, nil, fmt.Errorf("No connection pool found")
+		} else if len(pools) > 1 { // choose a random connection
+			currentPool = rand.Intn(len(pools))
+		} // if only one pool, currentPool defaults to 0, i.e., the only pool
+
+		// get the pool
+		pool := pools[currentPool]
+		conn, err := pool.Get()
+		if err != errClosedPool {
+			return conn, pool, err
+		}
+
+		// If conn pool was closed, because another goroutine refreshed the vbucket map, retry...
+	}
+}
+
+//
+// Get a random document from a bucket. Since the bucket may be distributed
+// across nodes, we must first select a random connection, and then use the
+// Client.GetRandomDoc() call to get a random document from that node.
+//
+
+func (b *Bucket) GetRandomDoc() (*gomemcached.MCResponse, error) {
+	// get a connection from the pool
+	conn, pool, err := b.getRandomConnection()
+
+	if err != nil {
+		return nil, err
+	}
+
+	// get a randomm document from the connection
+	doc, err := conn.GetRandomDoc()
+	// need to return the connection to the pool
+	pool.Return(conn)
+	return doc, err
+}
+
+func (b *Bucket) getMasterNode(i int) string {
+	p := b.getConnPools(false /* not already locked */)
+	if len(p) > i {
+		return p[i].host
+	}
+	return ""
+}
+
+func (b *Bucket) authHandler(bucketLocked bool) (ah AuthHandler) {
+	if !bucketLocked {
+		b.RLock()
+		defer b.RUnlock()
+	}
+	pool := b.pool
+	name := b.Name
+
+	if pool != nil {
+		ah = pool.client.ah
+	}
+	if mbah, ok := ah.(MultiBucketAuthHandler); ok {
+		return mbah.ForBucket(name)
+	}
+	if ah == nil {
+		ah = &basicAuth{name, ""}
+	}
+	return
+}
+
+// NodeAddresses gets the (sorted) list of memcached node addresses
+// (hostname:port).
+func (b *Bucket) NodeAddresses() []string {
+	vsm := b.VBServerMap()
+	rv := make([]string, len(vsm.ServerList))
+	copy(rv, vsm.ServerList)
+	sort.Strings(rv)
+	return rv
+}
+
+// CommonAddressSuffix finds the longest common suffix of all
+// host:port strings in the node list.
+func (b *Bucket) CommonAddressSuffix() string {
+	input := []string{}
+	for _, n := range b.Nodes() {
+		input = append(input, n.Hostname)
+	}
+	return FindCommonSuffix(input)
+}
+
+// A Client is the starting point for all services across all buckets
+// in a Couchbase cluster.
+type Client struct {
+	BaseURL *url.URL
+	ah      AuthHandler
+	Info    Pools
+}
+
+func maybeAddAuth(req *http.Request, ah AuthHandler) error {
+	if hah, ok := ah.(HTTPAuthHandler); ok {
+		return hah.SetCredsForRequest(req)
+	}
+	if ah != nil {
+		user, pass, _ := ah.GetCredentials()
+		req.Header.Set("Authorization", "Basic "+
+			base64.StdEncoding.EncodeToString([]byte(user+":"+pass)))
+	}
+	return nil
+}
+
+// arbitary number, may need to be tuned #FIXME
+const HTTP_MAX_RETRY = 5
+
+// Someday golang network packages will implement standard
+// error codes. Until then #sigh
+func isHttpConnError(err error) bool {
+
+	estr := err.Error()
+	return strings.Contains(estr, "broken pipe") ||
+		strings.Contains(estr, "broken connection") ||
+		strings.Contains(estr, "connection reset")
+}
+
+var client *http.Client
+
+func ClientConfigForX509(certFile, keyFile, rootFile string) (*tls.Config, error) {
+	cfg := &tls.Config{}
+
+	if certFile != "" && keyFile != "" {
+		tlsCert, err := tls.LoadX509KeyPair(certFile, keyFile)
+		if err != nil {
+			return nil, err
+		}
+		cfg.Certificates = []tls.Certificate{tlsCert}
+	} else {
+		//error need to pass both certfile and keyfile
+		return nil, fmt.Errorf("N1QL: Need to pass both certfile and keyfile")
+	}
+
+	var caCert []byte
+	var err1 error
+
+	caCertPool := x509.NewCertPool()
+	if rootFile != "" {
+		// Read that value in
+		caCert, err1 = ioutil.ReadFile(rootFile)
+		if err1 != nil {
+			return nil, fmt.Errorf(" Error in reading cacert file, err: %v", err1)
+		}
+		caCertPool.AppendCertsFromPEM(caCert)
+	}
+
+	cfg.RootCAs = caCertPool
+	return cfg, nil
+}
+
+func doHTTPRequest(req *http.Request) (*http.Response, error) {
+
+	var err error
+	var res *http.Response
+
+	tr := &http.Transport{}
+
+	// we need a client that ignores certificate errors, since we self-sign
+	// our certs
+	if client == nil && req.URL.Scheme == "https" {
+		if skipVerify {
+			tr = &http.Transport{
+				TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+			}
+		} else {
+			// Handle cases with cert
+
+			cfg, err := ClientConfigForX509(certFile, keyFile, rootFile)
+			if err != nil {
+				return nil, err
+			}
+
+			tr = &http.Transport{
+				TLSClientConfig: cfg,
+			}
+		}
+
+		client = &http.Client{Transport: tr}
+
+	} else if client == nil {
+		client = HTTPClient
+	}
+
+	for i := 0; i < HTTP_MAX_RETRY; i++ {
+		res, err = client.Do(req)
+		if err != nil && isHttpConnError(err) {
+			continue
+		}
+		break
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	return res, err
+}
+
+func doPutAPI(baseURL *url.URL, path string, params map[string]interface{}, authHandler AuthHandler, out interface{}) error {
+	return doOutputAPI("PUT", baseURL, path, params, authHandler, out)
+}
+
+func doPostAPI(baseURL *url.URL, path string, params map[string]interface{}, authHandler AuthHandler, out interface{}) error {
+	return doOutputAPI("POST", baseURL, path, params, authHandler, out)
+}
+
+func doOutputAPI(
+	httpVerb string,
+	baseURL *url.URL,
+	path string,
+	params map[string]interface{},
+	authHandler AuthHandler,
+	out interface{}) error {
+
+	var requestUrl string
+
+	if q := strings.Index(path, "?"); q > 0 {
+		requestUrl = baseURL.Scheme + "://" + baseURL.Host + path[:q] + "?" + path[q+1:]
+	} else {
+		requestUrl = baseURL.Scheme + "://" + baseURL.Host + path
+	}
+
+	postData := url.Values{}
+	for k, v := range params {
+		postData.Set(k, fmt.Sprintf("%v", v))
+	}
+
+	req, err := http.NewRequest(httpVerb, requestUrl, bytes.NewBufferString(postData.Encode()))
+	if err != nil {
+		return err
+	}
+
+	req.Header.Add("Content-Type", "application/x-www-form-urlencoded")
+
+	err = maybeAddAuth(req, authHandler)
+	if err != nil {
+		return err
+	}
+
+	res, err := doHTTPRequest(req)
+	if err != nil {
+		return err
+	}
+
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		bod, _ := ioutil.ReadAll(io.LimitReader(res.Body, 512))
+		return fmt.Errorf("HTTP error %v getting %q: %s",
+			res.Status, requestUrl, bod)
+	}
+
+	d := json.NewDecoder(res.Body)
+	if err = d.Decode(&out); err != nil {
+		return err
+	}
+	return nil
+}
+
+func queryRestAPI(
+	baseURL *url.URL,
+	path string,
+	authHandler AuthHandler,
+	out interface{}) error {
+
+	var requestUrl string
+
+	if q := strings.Index(path, "?"); q > 0 {
+		requestUrl = baseURL.Scheme + "://" + baseURL.Host + path[:q] + "?" + path[q+1:]
+	} else {
+		requestUrl = baseURL.Scheme + "://" + baseURL.Host + path
+	}
+
+	req, err := http.NewRequest("GET", requestUrl, nil)
+	if err != nil {
+		return err
+	}
+
+	err = maybeAddAuth(req, authHandler)
+	if err != nil {
+		return err
+	}
+
+	res, err := doHTTPRequest(req)
+	if err != nil {
+		return err
+	}
+
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		bod, _ := ioutil.ReadAll(io.LimitReader(res.Body, 512))
+		return fmt.Errorf("HTTP error %v getting %q: %s",
+			res.Status, requestUrl, bod)
+	}
+
+	d := json.NewDecoder(res.Body)
+	if err = d.Decode(&out); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (c *Client) ProcessStream(path string, callb func(interface{}) error, data interface{}) error {
+	return c.processStream(c.BaseURL, path, c.ah, callb, data)
+}
+
+// Based on code in http://src.couchbase.org/source/xref/trunk/goproj/src/github.com/couchbase/indexing/secondary/dcp/pools.go#309
+func (c *Client) processStream(baseURL *url.URL, path string, authHandler AuthHandler, callb func(interface{}) error, data interface{}) error {
+	var requestUrl string
+
+	if q := strings.Index(path, "?"); q > 0 {
+		requestUrl = baseURL.Scheme + "://" + baseURL.Host + path[:q] + "?" + path[q+1:]
+	} else {
+		requestUrl = baseURL.Scheme + "://" + baseURL.Host + path
+	}
+
+	req, err := http.NewRequest("GET", requestUrl, nil)
+	if err != nil {
+		return err
+	}
+
+	err = maybeAddAuth(req, authHandler)
+	if err != nil {
+		return err
+	}
+
+	res, err := doHTTPRequest(req)
+	if err != nil {
+		return err
+	}
+
+	defer res.Body.Close()
+	if res.StatusCode != 200 {
+		bod, _ := ioutil.ReadAll(io.LimitReader(res.Body, 512))
+		return fmt.Errorf("HTTP error %v getting %q: %s",
+			res.Status, requestUrl, bod)
+	}
+
+	reader := bufio.NewReader(res.Body)
+	for {
+		bs, err := reader.ReadBytes('\n')
+		if err != nil {
+			return err
+		}
+		if len(bs) == 1 && bs[0] == '\n' {
+			continue
+		}
+
+		err = json.Unmarshal(bs, data)
+		if err != nil {
+			return err
+		}
+		err = callb(data)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+
+}
+
+func (c *Client) parseURLResponse(path string, out interface{}) error {
+	return queryRestAPI(c.BaseURL, path, c.ah, out)
+}
+
+func (c *Client) parsePostURLResponse(path string, params map[string]interface{}, out interface{}) error {
+	return doPostAPI(c.BaseURL, path, params, c.ah, out)
+}
+
+func (c *Client) parsePutURLResponse(path string, params map[string]interface{}, out interface{}) error {
+	return doPutAPI(c.BaseURL, path, params, c.ah, out)
+}
+
+func (b *Bucket) parseURLResponse(path string, out interface{}) error {
+	nodes := b.Nodes()
+	if len(nodes) == 0 {
+		return errors.New("no couch rest URLs")
+	}
+
+	// Pick a random node to start querying.
+	startNode := rand.Intn(len(nodes))
+	maxRetries := len(nodes)
+	for i := 0; i < maxRetries; i++ {
+		node := nodes[(startNode+i)%len(nodes)] // Wrap around the nodes list.
+		// Skip non-healthy nodes.
+		if node.Status != "healthy" || node.CouchAPIBase == "" {
+			continue
+		}
+		url := &url.URL{
+			Host:   node.Hostname,
+			Scheme: "http",
+		}
+
+		// Lock here to avoid having pool closed under us.
+		b.RLock()
+		err := queryRestAPI(url, path, b.pool.client.ah, out)
+		b.RUnlock()
+		if err == nil {
+			return err
+		}
+	}
+	return errors.New("All nodes failed to respond or no healthy nodes for bucket found")
+}
+
+func (b *Bucket) parseAPIResponse(path string, out interface{}) error {
+	nodes := b.Nodes()
+	if len(nodes) == 0 {
+		return errors.New("no couch rest URLs")
+	}
+
+	var err error
+	var u *url.URL
+
+	// Pick a random node to start querying.
+	startNode := rand.Intn(len(nodes))
+	maxRetries := len(nodes)
+	for i := 0; i < maxRetries; i++ {
+		node := nodes[(startNode+i)%len(nodes)] // Wrap around the nodes list.
+		// Skip non-healthy nodes.
+		if node.Status != "healthy" || node.CouchAPIBase == "" {
+			continue
+		}
+
+		u, err = ParseURL(node.CouchAPIBase)
+		// Lock here so pool does not get closed under us.
+		b.RLock()
+		if err != nil {
+			b.RUnlock()
+			return fmt.Errorf("config error: Bucket %q node #%d CouchAPIBase=%q: %v",
+				b.Name, i, node.CouchAPIBase, err)
+		} else if b.pool != nil {
+			u.User = b.pool.client.BaseURL.User
+		}
+		u.Path = path
+
+		// generate the path so that the strings are properly escaped
+		// MB-13770
+		requestPath := strings.Split(u.String(), u.Host)[1]
+
+		err = queryRestAPI(u, requestPath, b.pool.client.ah, out)
+		b.RUnlock()
+		if err == nil {
+			return err
+		}
+	}
+
+	var errStr string
+	if err != nil {
+		errStr = "Error " + err.Error()
+	}
+
+	return errors.New("All nodes failed to respond or returned error or no healthy nodes for bucket found." + errStr)
+}
+
+type basicAuth struct {
+	u, p string
+}
+
+func (b basicAuth) GetCredentials() (string, string, string) {
+	return b.u, b.p, b.u
+}
+
+func basicAuthFromURL(us string) (ah AuthHandler) {
+	u, err := ParseURL(us)
+	if err != nil {
+		return
+	}
+	if user := u.User; user != nil {
+		pw, _ := user.Password()
+		ah = basicAuth{user.Username(), pw}
+	}
+	return
+}
+
+// ConnectWithAuth connects to a couchbase cluster with the given
+// authentication handler.
+func ConnectWithAuth(baseU string, ah AuthHandler) (c Client, err error) {
+	c.BaseURL, err = ParseURL(baseU)
+	if err != nil {
+		return
+	}
+	c.ah = ah
+
+	return c, c.parseURLResponse("/pools", &c.Info)
+}
+
+// ConnectWithAuthCreds connects to a couchbase cluster with the give
+// authorization creds returned by cb_auth
+func ConnectWithAuthCreds(baseU, username, password string) (c Client, err error) {
+	c.BaseURL, err = ParseURL(baseU)
+	if err != nil {
+		return
+	}
+
+	c.ah = newBucketAuth(username, password, "")
+	return c, c.parseURLResponse("/pools", &c.Info)
+
+}
+
+// Connect to a couchbase cluster.  An authentication handler will be
+// created from the userinfo in the URL if provided.
+func Connect(baseU string) (Client, error) {
+	return ConnectWithAuth(baseU, basicAuthFromURL(baseU))
+}
+
+type BucketInfo struct {
+	Name     string // name of bucket
+	Password string // SASL password of bucket
+}
+
+//Get SASL buckets
+func GetBucketList(baseU string) (bInfo []BucketInfo, err error) {
+
+	c := &Client{}
+	c.BaseURL, err = ParseURL(baseU)
+	if err != nil {
+		return
+	}
+	c.ah = basicAuthFromURL(baseU)
+
+	var buckets []Bucket
+	err = c.parseURLResponse("/pools/default/buckets", &buckets)
+	if err != nil {
+		return
+	}
+	bInfo = make([]BucketInfo, 0)
+	for _, bucket := range buckets {
+		bucketInfo := BucketInfo{Name: bucket.Name, Password: bucket.Password}
+		bInfo = append(bInfo, bucketInfo)
+	}
+	return bInfo, err
+}
+
+//Set viewUpdateDaemonOptions
+func SetViewUpdateParams(baseU string, params map[string]interface{}) (viewOpts map[string]interface{}, err error) {
+
+	c := &Client{}
+	c.BaseURL, err = ParseURL(baseU)
+	if err != nil {
+		return
+	}
+	c.ah = basicAuthFromURL(baseU)
+
+	if len(params) < 1 {
+		return nil, fmt.Errorf("No params to set")
+	}
+
+	err = c.parsePostURLResponse("/settings/viewUpdateDaemon", params, &viewOpts)
+	if err != nil {
+		return
+	}
+	return viewOpts, err
+}
+
+// This API lets the caller know, if the list of nodes a bucket is
+// connected to has gone through an edit (a rebalance operation)
+// since the last update to the bucket, in which case a Refresh is
+// advised.
+func (b *Bucket) NodeListChanged() bool {
+	b.RLock()
+	pool := b.pool
+	uri := b.URI
+	b.RUnlock()
+
+	tmpb := &Bucket{}
+	err := pool.client.parseURLResponse(uri, tmpb)
+	if err != nil {
+		return true
+	}
+
+	bNodes := *(*[]Node)(b.nodeList)
+	if len(bNodes) != len(tmpb.NodesJSON) {
+		return true
+	}
+
+	bucketHostnames := map[string]bool{}
+	for _, node := range bNodes {
+		bucketHostnames[node.Hostname] = true
+	}
+
+	for _, node := range tmpb.NodesJSON {
+		if _, found := bucketHostnames[node.Hostname]; !found {
+			return true
+		}
+	}
+
+	return false
+}
+
+// Sample data for scopes and collections as returned from the
+// /pooles/default/$BUCKET_NAME/collections API.
+// {"myScope2":{"myCollectionC":{}},"myScope1":{"myCollectionB":{},"myCollectionA":{}},"_default":{"_default":{}}}
+
+// A Scopes holds the set of scopes in a bucket.
+// The map key is the name of the scope.
+type Scopes map[string]Collections
+
+// A Collections holds the set of collections in a scope.
+// The map key is the name of the collection.
+type Collections map[string]Collection
+
+// A Collection holds the information for a collection.
+// It is currently returned empty.
+type Collection struct{}
+
+func getScopesAndCollections(pool *Pool, bucketName string) (Scopes, error) {
+	scopes := make(Scopes)
+	// This URL is a bit of a hack. The "default" is the name of the pool, and should
+	// be a parameter. But the name does not appear to be available anywhere,
+	// and in any case we never use a pool other than "default".
+	err := pool.client.parseURLResponse(fmt.Sprintf("/pools/default/buckets/%s/collections", bucketName), &scopes)
+	if err != nil {
+		return nil, err
+	}
+	return scopes, nil
+}
+
+func (b *Bucket) Refresh() error {
+	b.RLock()
+	pool := b.pool
+	uri := b.URI
+	name := b.Name
+	b.RUnlock()
+
+	tmpb := &Bucket{}
+	err := pool.client.parseURLResponse(uri, tmpb)
+	if err != nil {
+		return err
+	}
+
+	scopes, err := getScopesAndCollections(pool, name)
+	if err != nil {
+		return err
+	}
+
+	pools := b.getConnPools(false /* bucket not already locked */)
+
+	// We need this lock to ensure that bucket refreshes happening because
+	// of NMVb errors received during bulkGet do not end up over-writing
+	// pool.inUse.
+	b.Lock()
+
+	for _, pool := range pools {
+		if pool != nil {
+			pool.inUse = false
+		}
+	}
+
+	newcps := make([]*connectionPool, len(tmpb.VBSMJson.ServerList))
+	for i := range newcps {
+
+		pool := b.getConnPoolByHost(tmpb.VBSMJson.ServerList[i], true /* bucket already locked */)
+		if pool != nil && pool.inUse == false {
+			// if the hostname and index is unchanged then reuse this pool
+			newcps[i] = pool
+			pool.inUse = true
+			continue
+		}
+
+		if b.ah != nil {
+			newcps[i] = newConnectionPool(
+				tmpb.VBSMJson.ServerList[i],
+				b.ah, AsynchronousCloser, PoolSize, PoolOverflow)
+
+		} else {
+			newcps[i] = newConnectionPool(
+				tmpb.VBSMJson.ServerList[i],
+				b.authHandler(true /* bucket already locked */),
+				AsynchronousCloser, PoolSize, PoolOverflow)
+		}
+	}
+	b.replaceConnPools2(newcps, true /* bucket already locked */)
+	tmpb.ah = b.ah
+	b.vBucketServerMap = unsafe.Pointer(&tmpb.VBSMJson)
+	b.nodeList = unsafe.Pointer(&tmpb.NodesJSON)
+	b.Scopes = scopes
+
+	b.Unlock()
+	return nil
+}
+
+func (p *Pool) refresh() (err error) {
+	p.BucketMap = make(map[string]Bucket)
+
+	buckets := []Bucket{}
+	err = p.client.parseURLResponse(p.BucketURL["uri"], &buckets)
+	if err != nil {
+		return err
+	}
+	for _, b := range buckets {
+		b.pool = p
+		b.nodeList = unsafe.Pointer(&b.NodesJSON)
+		b.replaceConnPools(make([]*connectionPool, len(b.VBSMJson.ServerList)))
+
+		p.BucketMap[b.Name] = b
+	}
+	return nil
+}
+
+// GetPool gets a pool from within the couchbase cluster (usually
+// "default").
+func (c *Client) GetPool(name string) (p Pool, err error) {
+	var poolURI string
+	for _, p := range c.Info.Pools {
+		if p.Name == name {
+			poolURI = p.URI
+		}
+	}
+	if poolURI == "" {
+		return p, errors.New("No pool named " + name)
+	}
+
+	err = c.parseURLResponse(poolURI, &p)
+
+	p.client = *c
+
+	err = p.refresh()
+	return
+}
+
+// GetPoolServices returns all the bucket-independent services in a pool.
+// (See "Exposing services outside of bucket context" in http://goo.gl/uuXRkV)
+func (c *Client) GetPoolServices(name string) (ps PoolServices, err error) {
+	var poolName string
+	for _, p := range c.Info.Pools {
+		if p.Name == name {
+			poolName = p.Name
+		}
+	}
+	if poolName == "" {
+		return ps, errors.New("No pool named " + name)
+	}
+
+	poolURI := "/pools/" + poolName + "/nodeServices"
+	err = c.parseURLResponse(poolURI, &ps)
+
+	return
+}
+
+// Close marks this bucket as no longer needed, closing connections it
+// may have open.
+func (b *Bucket) Close() {
+	b.Lock()
+	defer b.Unlock()
+	if b.connPools != nil {
+		for _, c := range b.getConnPools(true /* already locked */) {
+			if c != nil {
+				c.Close()
+			}
+		}
+		b.connPools = nil
+	}
+}
+
+func bucketFinalizer(b *Bucket) {
+	if b.connPools != nil {
+		logging.Warnf("Finalizing a bucket with active connections.")
+	}
+}
+
+// GetBucket gets a bucket from within this pool.
+func (p *Pool) GetBucket(name string) (*Bucket, error) {
+	rv, ok := p.BucketMap[name]
+	if !ok {
+		return nil, &BucketNotFoundError{bucket: name}
+	}
+	runtime.SetFinalizer(&rv, bucketFinalizer)
+	err := rv.Refresh()
+	if err != nil {
+		return nil, err
+	}
+	return &rv, nil
+}
+
+// GetBucket gets a bucket from within this pool.
+func (p *Pool) GetBucketWithAuth(bucket, username, password string) (*Bucket, error) {
+	rv, ok := p.BucketMap[bucket]
+	if !ok {
+		return nil, &BucketNotFoundError{bucket: bucket}
+	}
+	runtime.SetFinalizer(&rv, bucketFinalizer)
+	rv.ah = newBucketAuth(username, password, bucket)
+	err := rv.Refresh()
+	if err != nil {
+		return nil, err
+	}
+	return &rv, nil
+}
+
+// GetPool gets the pool to which this bucket belongs.
+func (b *Bucket) GetPool() *Pool {
+	b.RLock()
+	defer b.RUnlock()
+	ret := b.pool
+	return ret
+}
+
+// GetClient gets the client from which we got this pool.
+func (p *Pool) GetClient() *Client {
+	return &p.client
+}
+
+// GetBucket is a convenience function for getting a named bucket from
+// a URL
+func GetBucket(endpoint, poolname, bucketname string) (*Bucket, error) {
+	var err error
+	client, err := Connect(endpoint)
+	if err != nil {
+		return nil, err
+	}
+
+	pool, err := client.GetPool(poolname)
+	if err != nil {
+		return nil, err
+	}
+
+	return pool.GetBucket(bucketname)
+}
+
+// ConnectWithAuthAndGetBucket is a convenience function for
+// getting a named bucket from a given URL and an auth callback
+func ConnectWithAuthAndGetBucket(endpoint, poolname, bucketname string,
+	ah AuthHandler) (*Bucket, error) {
+	client, err := ConnectWithAuth(endpoint, ah)
+	if err != nil {
+		return nil, err
+	}
+
+	pool, err := client.GetPool(poolname)
+	if err != nil {
+		return nil, err
+	}
+
+	return pool.GetBucket(bucketname)
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/streaming.go b/vendor/github.com/couchbaselabs/go-couchbase/streaming.go
new file mode 100644
index 0000000000..6467635371
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/streaming.go
@@ -0,0 +1,209 @@
+package couchbase
+
+import (
+	"encoding/json"
+	"fmt"
+	"github.com/couchbase/goutils/logging"
+	"io"
+	"io/ioutil"
+	"math/rand"
+	"net"
+	"net/http"
+	"time"
+	"unsafe"
+)
+
+// Bucket auto-updater gets the latest version of the bucket config from
+// the server. If the configuration has changed then updated the local
+// bucket information. If the bucket has been deleted then notify anyone
+// who is holding a reference to this bucket
+
+const MAX_RETRY_COUNT = 5
+const DISCONNECT_PERIOD = 120 * time.Second
+
+type NotifyFn func(bucket string, err error)
+
+// Use TCP keepalive to detect half close sockets
+var updaterTransport http.RoundTripper = &http.Transport{
+	Proxy: http.ProxyFromEnvironment,
+	Dial: (&net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 30 * time.Second,
+	}).Dial,
+}
+
+var updaterHTTPClient = &http.Client{Transport: updaterTransport}
+
+func doHTTPRequestForUpdate(req *http.Request) (*http.Response, error) {
+
+	var err error
+	var res *http.Response
+
+	for i := 0; i < HTTP_MAX_RETRY; i++ {
+		res, err = updaterHTTPClient.Do(req)
+		if err != nil && isHttpConnError(err) {
+			continue
+		}
+		break
+	}
+
+	if err != nil {
+		return nil, err
+	}
+
+	return res, err
+}
+
+func (b *Bucket) RunBucketUpdater(notify NotifyFn) {
+	go func() {
+		err := b.UpdateBucket()
+		if err != nil {
+			if notify != nil {
+				notify(b.GetName(), err)
+			}
+			logging.Errorf(" Bucket Updater exited with err %v", err)
+		}
+	}()
+}
+
+func (b *Bucket) replaceConnPools2(with []*connectionPool, bucketLocked bool) {
+	if !bucketLocked {
+		b.Lock()
+		defer b.Unlock()
+	}
+	old := b.connPools
+	b.connPools = unsafe.Pointer(&with)
+	if old != nil {
+		for _, pool := range *(*[]*connectionPool)(old) {
+			if pool != nil && pool.inUse == false {
+				pool.Close()
+			}
+		}
+	}
+	return
+}
+
+func (b *Bucket) UpdateBucket() error {
+
+	var failures int
+	var returnErr error
+
+	for {
+
+		if failures == MAX_RETRY_COUNT {
+			logging.Errorf(" Maximum failures reached. Exiting loop...")
+			return fmt.Errorf("Max failures reached. Last Error %v", returnErr)
+		}
+
+		nodes := b.Nodes()
+		if len(nodes) < 1 {
+			return fmt.Errorf("No healthy nodes found")
+		}
+
+		startNode := rand.Intn(len(nodes))
+		node := nodes[(startNode)%len(nodes)]
+
+		streamUrl := fmt.Sprintf("http://%s/pools/default/bucketsStreaming/%s", node.Hostname, b.GetName())
+		logging.Infof(" Trying with %s", streamUrl)
+		req, err := http.NewRequest("GET", streamUrl, nil)
+		if err != nil {
+			return err
+		}
+
+		b.RLock()
+		pool := b.pool
+		bucketName := b.Name
+		b.RUnlock()
+		scopes, err := getScopesAndCollections(pool, bucketName)
+		if err != nil {
+			return err
+		}
+
+		// Lock here to avoid having pool closed under us.
+		b.RLock()
+		err = maybeAddAuth(req, b.pool.client.ah)
+		b.RUnlock()
+		if err != nil {
+			return err
+		}
+
+		res, err := doHTTPRequestForUpdate(req)
+		if err != nil {
+			return err
+		}
+
+		if res.StatusCode != 200 {
+			bod, _ := ioutil.ReadAll(io.LimitReader(res.Body, 512))
+			logging.Errorf("Failed to connect to host, unexpected status code: %v. Body %s", res.StatusCode, bod)
+			res.Body.Close()
+			returnErr = fmt.Errorf("Failed to connect to host. Status %v Body %s", res.StatusCode, bod)
+			failures++
+			continue
+		}
+
+		dec := json.NewDecoder(res.Body)
+
+		tmpb := &Bucket{}
+		for {
+
+			err := dec.Decode(&tmpb)
+			if err != nil {
+				returnErr = err
+				res.Body.Close()
+				break
+			}
+
+			// if we got here, reset failure count
+			failures = 0
+			b.Lock()
+
+			// mark all the old connection pools for deletion
+			pools := b.getConnPools(true /* already locked */)
+			for _, pool := range pools {
+				if pool != nil {
+					pool.inUse = false
+				}
+			}
+
+			newcps := make([]*connectionPool, len(tmpb.VBSMJson.ServerList))
+			for i := range newcps {
+				// get the old connection pool and check if it is still valid
+				pool := b.getConnPoolByHost(tmpb.VBSMJson.ServerList[i], true /* bucket already locked */)
+				if pool != nil && pool.inUse == false {
+					// if the hostname and index is unchanged then reuse this pool
+					newcps[i] = pool
+					pool.inUse = true
+					continue
+				}
+				// else create a new pool
+				if b.ah != nil {
+					newcps[i] = newConnectionPool(
+						tmpb.VBSMJson.ServerList[i],
+						b.ah, false, PoolSize, PoolOverflow)
+
+				} else {
+					newcps[i] = newConnectionPool(
+						tmpb.VBSMJson.ServerList[i],
+						b.authHandler(true /* bucket already locked */),
+						false, PoolSize, PoolOverflow)
+				}
+			}
+
+			b.replaceConnPools2(newcps, true /* bucket already locked */)
+
+			tmpb.ah = b.ah
+			b.vBucketServerMap = unsafe.Pointer(&tmpb.VBSMJson)
+			b.nodeList = unsafe.Pointer(&tmpb.NodesJSON)
+			b.Scopes = scopes
+			b.Unlock()
+
+			logging.Infof("Got new configuration for bucket %s", b.GetName())
+
+		}
+		// we are here because of an error
+		failures++
+		continue
+
+	}
+	return nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/tap.go b/vendor/github.com/couchbaselabs/go-couchbase/tap.go
new file mode 100644
index 0000000000..86edd30554
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/tap.go
@@ -0,0 +1,143 @@
+package couchbase
+
+import (
+	"github.com/couchbase/gomemcached/client"
+	"github.com/couchbase/goutils/logging"
+	"sync"
+	"time"
+)
+
+const initialRetryInterval = 1 * time.Second
+const maximumRetryInterval = 30 * time.Second
+
+// A TapFeed streams mutation events from a bucket.
+//
+// Events from the bucket can be read from the channel 'C'.  Remember
+// to call Close() on it when you're done, unless its channel has
+// closed itself already.
+type TapFeed struct {
+	C <-chan memcached.TapEvent
+
+	bucket    *Bucket
+	args      *memcached.TapArguments
+	nodeFeeds []*memcached.TapFeed    // The TAP feeds of the individual nodes
+	output    chan memcached.TapEvent // Same as C but writeably-typed
+	wg        sync.WaitGroup
+	quit      chan bool
+}
+
+// StartTapFeed creates and starts a new Tap feed
+func (b *Bucket) StartTapFeed(args *memcached.TapArguments) (*TapFeed, error) {
+	if args == nil {
+		defaultArgs := memcached.DefaultTapArguments()
+		args = &defaultArgs
+	}
+
+	feed := &TapFeed{
+		bucket: b,
+		args:   args,
+		output: make(chan memcached.TapEvent, 10),
+		quit:   make(chan bool),
+	}
+
+	go feed.run()
+
+	feed.C = feed.output
+	return feed, nil
+}
+
+// Goroutine that runs the feed
+func (feed *TapFeed) run() {
+	retryInterval := initialRetryInterval
+	bucketOK := true
+	for {
+		// Connect to the TAP feed of each server node:
+		if bucketOK {
+			killSwitch, err := feed.connectToNodes()
+			if err == nil {
+				// Run until one of the sub-feeds fails:
+				select {
+				case <-killSwitch:
+				case <-feed.quit:
+					return
+				}
+				feed.closeNodeFeeds()
+				retryInterval = initialRetryInterval
+			}
+		}
+
+		// On error, try to refresh the bucket in case the list of nodes changed:
+		logging.Infof("go-couchbase: TAP connection lost; reconnecting to bucket %q in %v",
+			feed.bucket.Name, retryInterval)
+		err := feed.bucket.Refresh()
+		bucketOK = err == nil
+
+		select {
+		case <-time.After(retryInterval):
+		case <-feed.quit:
+			return
+		}
+		if retryInterval *= 2; retryInterval > maximumRetryInterval {
+			retryInterval = maximumRetryInterval
+		}
+	}
+}
+
+func (feed *TapFeed) connectToNodes() (killSwitch chan bool, err error) {
+	killSwitch = make(chan bool)
+	for _, serverConn := range feed.bucket.getConnPools(false /* not already locked */) {
+		var singleFeed *memcached.TapFeed
+		singleFeed, err = serverConn.StartTapFeed(feed.args)
+		if err != nil {
+			logging.Errorf("go-couchbase: Error connecting to tap feed of %s: %v", serverConn.host, err)
+			feed.closeNodeFeeds()
+			return
+		}
+		feed.nodeFeeds = append(feed.nodeFeeds, singleFeed)
+		go feed.forwardTapEvents(singleFeed, killSwitch, serverConn.host)
+		feed.wg.Add(1)
+	}
+	return
+}
+
+// Goroutine that forwards Tap events from a single node's feed to the aggregate feed.
+func (feed *TapFeed) forwardTapEvents(singleFeed *memcached.TapFeed, killSwitch chan bool, host string) {
+	defer feed.wg.Done()
+	for {
+		select {
+		case event, ok := <-singleFeed.C:
+			if !ok {
+				if singleFeed.Error != nil {
+					logging.Errorf("go-couchbase: Tap feed from %s failed: %v", host, singleFeed.Error)
+				}
+				killSwitch <- true
+				return
+			}
+			feed.output <- event
+		case <-feed.quit:
+			return
+		}
+	}
+}
+
+func (feed *TapFeed) closeNodeFeeds() {
+	for _, f := range feed.nodeFeeds {
+		f.Close()
+	}
+	feed.nodeFeeds = nil
+}
+
+// Close a Tap feed.
+func (feed *TapFeed) Close() error {
+	select {
+	case <-feed.quit:
+		return nil
+	default:
+	}
+
+	feed.closeNodeFeeds()
+	close(feed.quit)
+	feed.wg.Wait()
+	close(feed.output)
+	return nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/upr.go b/vendor/github.com/couchbaselabs/go-couchbase/upr.go
new file mode 100644
index 0000000000..bf1b209b7e
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/upr.go
@@ -0,0 +1,398 @@
+package couchbase
+
+import (
+	"log"
+	"sync"
+	"time"
+
+	"fmt"
+	"github.com/couchbase/gomemcached"
+	"github.com/couchbase/gomemcached/client"
+	"github.com/couchbase/goutils/logging"
+)
+
+// A UprFeed streams mutation events from a bucket.
+//
+// Events from the bucket can be read from the channel 'C'.  Remember
+// to call Close() on it when you're done, unless its channel has
+// closed itself already.
+type UprFeed struct {
+	C <-chan *memcached.UprEvent
+
+	bucket          *Bucket
+	nodeFeeds       map[string]*FeedInfo     // The UPR feeds of the individual nodes
+	output          chan *memcached.UprEvent // Same as C but writeably-typed
+	outputClosed    bool
+	quit            chan bool
+	name            string // name of this UPR feed
+	sequence        uint32 // sequence number for this feed
+	connected       bool
+	killSwitch      chan bool
+	closing         bool
+	wg              sync.WaitGroup
+	dcp_buffer_size uint32
+	data_chan_size  int
+}
+
+// UprFeed from a single connection
+type FeedInfo struct {
+	uprFeed   *memcached.UprFeed // UPR feed handle
+	host      string             // hostname
+	connected bool               // connected
+	quit      chan bool          // quit channel
+}
+
+type FailoverLog map[uint16]memcached.FailoverLog
+
+// GetFailoverLogs, get the failover logs for a set of vbucket ids
+func (b *Bucket) GetFailoverLogs(vBuckets []uint16) (FailoverLog, error) {
+
+	// map vbids to their corresponding hosts
+	vbHostList := make(map[string][]uint16)
+	vbm := b.VBServerMap()
+	if len(vbm.VBucketMap) < len(vBuckets) {
+		return nil, fmt.Errorf("vbmap smaller than vbucket list: %v vs. %v",
+			vbm.VBucketMap, vBuckets)
+	}
+
+	for _, vb := range vBuckets {
+		masterID := vbm.VBucketMap[vb][0]
+		master := b.getMasterNode(masterID)
+		if master == "" {
+			return nil, fmt.Errorf("No master found for vb %d", vb)
+		}
+
+		vbList := vbHostList[master]
+		if vbList == nil {
+			vbList = make([]uint16, 0)
+		}
+		vbList = append(vbList, vb)
+		vbHostList[master] = vbList
+	}
+
+	failoverLogMap := make(FailoverLog)
+	for _, serverConn := range b.getConnPools(false /* not already locked */) {
+
+		vbList := vbHostList[serverConn.host]
+		if vbList == nil {
+			continue
+		}
+
+		mc, err := serverConn.Get()
+		if err != nil {
+			logging.Infof("No Free connections for vblist %v", vbList)
+			return nil, fmt.Errorf("No Free connections for host %s",
+				serverConn.host)
+
+		}
+		// close the connection so that it doesn't get reused for upr data
+		// connection
+		defer mc.Close()
+		failoverlogs, err := mc.UprGetFailoverLog(vbList)
+		if err != nil {
+			return nil, fmt.Errorf("Error getting failover log %s host %s",
+				err.Error(), serverConn.host)
+
+		}
+
+		for vb, log := range failoverlogs {
+			failoverLogMap[vb] = *log
+		}
+	}
+
+	return failoverLogMap, nil
+}
+
+func (b *Bucket) StartUprFeed(name string, sequence uint32) (*UprFeed, error) {
+	return b.StartUprFeedWithConfig(name, sequence, 10, DEFAULT_WINDOW_SIZE)
+}
+
+// StartUprFeed creates and starts a new Upr feed
+// No data will be sent on the channel unless vbuckets streams are requested
+func (b *Bucket) StartUprFeedWithConfig(name string, sequence uint32, data_chan_size int, dcp_buffer_size uint32) (*UprFeed, error) {
+
+	feed := &UprFeed{
+		bucket:          b,
+		output:          make(chan *memcached.UprEvent, data_chan_size),
+		quit:            make(chan bool),
+		nodeFeeds:       make(map[string]*FeedInfo, 0),
+		name:            name,
+		sequence:        sequence,
+		killSwitch:      make(chan bool),
+		dcp_buffer_size: dcp_buffer_size,
+		data_chan_size:  data_chan_size,
+	}
+
+	err := feed.connectToNodes()
+	if err != nil {
+		return nil, fmt.Errorf("Cannot connect to bucket %s", err.Error())
+	}
+	feed.connected = true
+	go feed.run()
+
+	feed.C = feed.output
+	return feed, nil
+}
+
+// UprRequestStream starts a stream for a vb on a feed
+func (feed *UprFeed) UprRequestStream(vb uint16, opaque uint16, flags uint32,
+	vuuid, startSequence, endSequence, snapStart, snapEnd uint64) error {
+
+	defer func() {
+		if r := recover(); r != nil {
+			log.Panicf("Panic in UprRequestStream. Feed %v Bucket %v", feed, feed.bucket)
+		}
+	}()
+
+	vbm := feed.bucket.VBServerMap()
+	if len(vbm.VBucketMap) < int(vb) {
+		return fmt.Errorf("vbmap smaller than vbucket list: %v vs. %v",
+			vb, vbm.VBucketMap)
+	}
+
+	if int(vb) >= len(vbm.VBucketMap) {
+		return fmt.Errorf("Invalid vbucket id %d", vb)
+	}
+
+	masterID := vbm.VBucketMap[vb][0]
+	master := feed.bucket.getMasterNode(masterID)
+	if master == "" {
+		return fmt.Errorf("Master node not found for vbucket %d", vb)
+	}
+	singleFeed := feed.nodeFeeds[master]
+	if singleFeed == nil {
+		return fmt.Errorf("UprFeed for this host not found")
+	}
+
+	if err := singleFeed.uprFeed.UprRequestStream(vb, opaque, flags,
+		vuuid, startSequence, endSequence, snapStart, snapEnd); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// UprCloseStream ends a vbucket stream.
+func (feed *UprFeed) UprCloseStream(vb, opaqueMSB uint16) error {
+
+	defer func() {
+		if r := recover(); r != nil {
+			log.Panicf("Panic in UprCloseStream. Feed %v Bucket %v ", feed, feed.bucket)
+		}
+	}()
+
+	vbm := feed.bucket.VBServerMap()
+	if len(vbm.VBucketMap) < int(vb) {
+		return fmt.Errorf("vbmap smaller than vbucket list: %v vs. %v",
+			vb, vbm.VBucketMap)
+	}
+
+	if int(vb) >= len(vbm.VBucketMap) {
+		return fmt.Errorf("Invalid vbucket id %d", vb)
+	}
+
+	masterID := vbm.VBucketMap[vb][0]
+	master := feed.bucket.getMasterNode(masterID)
+	if master == "" {
+		return fmt.Errorf("Master node not found for vbucket %d", vb)
+	}
+	singleFeed := feed.nodeFeeds[master]
+	if singleFeed == nil {
+		return fmt.Errorf("UprFeed for this host not found")
+	}
+
+	if err := singleFeed.uprFeed.CloseStream(vb, opaqueMSB); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Goroutine that runs the feed
+func (feed *UprFeed) run() {
+	retryInterval := initialRetryInterval
+	bucketOK := true
+	for {
+		// Connect to the UPR feed of each server node:
+		if bucketOK {
+			// Run until one of the sub-feeds fails:
+			select {
+			case <-feed.killSwitch:
+			case <-feed.quit:
+				return
+			}
+			//feed.closeNodeFeeds()
+			retryInterval = initialRetryInterval
+		}
+
+		if feed.closing == true {
+			// we have been asked to shut down
+			return
+		}
+
+		// On error, try to refresh the bucket in case the list of nodes changed:
+		logging.Infof("go-couchbase: UPR connection lost; reconnecting to bucket %q in %v",
+			feed.bucket.Name, retryInterval)
+
+		if err := feed.bucket.Refresh(); err != nil {
+			// if we fail to refresh the bucket, exit the feed
+			// MB-14917
+			logging.Infof("Unable to refresh bucket %s ", err.Error())
+			close(feed.output)
+			feed.outputClosed = true
+			feed.closeNodeFeeds()
+			return
+		}
+
+		// this will only connect to nodes that are not connected or changed
+		// user will have to reconnect the stream
+		err := feed.connectToNodes()
+		if err != nil {
+			logging.Infof("Unable to connect to nodes..exit ")
+			close(feed.output)
+			feed.outputClosed = true
+			feed.closeNodeFeeds()
+			return
+		}
+		bucketOK = err == nil
+
+		select {
+		case <-time.After(retryInterval):
+		case <-feed.quit:
+			return
+		}
+		if retryInterval *= 2; retryInterval > maximumRetryInterval {
+			retryInterval = maximumRetryInterval
+		}
+	}
+}
+
+func (feed *UprFeed) connectToNodes() (err error) {
+	nodeCount := 0
+	for _, serverConn := range feed.bucket.getConnPools(false /* not already locked */) {
+
+		// this maybe a reconnection, so check if the connection to the node
+		// already exists. Connect only if the node is not found in the list
+		// or connected == false
+		nodeFeed := feed.nodeFeeds[serverConn.host]
+
+		if nodeFeed != nil && nodeFeed.connected == true {
+			continue
+		}
+
+		var singleFeed *memcached.UprFeed
+		var name string
+		if feed.name == "" {
+			name = "DefaultUprClient"
+		} else {
+			name = feed.name
+		}
+		singleFeed, err = serverConn.StartUprFeed(name, feed.sequence, feed.dcp_buffer_size, feed.data_chan_size)
+		if err != nil {
+			logging.Errorf("go-couchbase: Error connecting to upr feed of %s: %v", serverConn.host, err)
+			feed.closeNodeFeeds()
+			return
+		}
+		// add the node to the connection map
+		feedInfo := &FeedInfo{
+			uprFeed:   singleFeed,
+			connected: true,
+			host:      serverConn.host,
+			quit:      make(chan bool),
+		}
+		feed.nodeFeeds[serverConn.host] = feedInfo
+		go feed.forwardUprEvents(feedInfo, feed.killSwitch, serverConn.host)
+		feed.wg.Add(1)
+		nodeCount++
+	}
+	if nodeCount == 0 {
+		return fmt.Errorf("No connection to bucket")
+	}
+
+	return nil
+}
+
+// Goroutine that forwards Upr events from a single node's feed to the aggregate feed.
+func (feed *UprFeed) forwardUprEvents(nodeFeed *FeedInfo, killSwitch chan bool, host string) {
+	singleFeed := nodeFeed.uprFeed
+
+	defer func() {
+		feed.wg.Done()
+		if r := recover(); r != nil {
+			//if feed is not closing, re-throw the panic
+			if feed.outputClosed != true && feed.closing != true {
+				panic(r)
+			} else {
+				logging.Errorf("Panic is recovered. Since feed is closed, exit gracefully")
+
+			}
+		}
+	}()
+
+	for {
+		select {
+		case <-nodeFeed.quit:
+			nodeFeed.connected = false
+			return
+
+		case event, ok := <-singleFeed.C:
+			if !ok {
+				if singleFeed.Error != nil {
+					logging.Errorf("go-couchbase: Upr feed from %s failed: %v", host, singleFeed.Error)
+				}
+				killSwitch <- true
+				return
+			}
+			if feed.outputClosed == true {
+				// someone closed the node feed
+				logging.Infof("Node need closed, returning from forwardUprEvent")
+				return
+			}
+			feed.output <- event
+			if event.Status == gomemcached.NOT_MY_VBUCKET {
+				logging.Infof(" Got a not my vbucket error !! ")
+				if err := feed.bucket.Refresh(); err != nil {
+					logging.Errorf("Unable to refresh bucket %s ", err.Error())
+					feed.closeNodeFeeds()
+					return
+				}
+				// this will only connect to nodes that are not connected or changed
+				// user will have to reconnect the stream
+				if err := feed.connectToNodes(); err != nil {
+					logging.Errorf("Unable to connect to nodes %s", err.Error())
+					return
+				}
+
+			}
+		}
+	}
+}
+
+func (feed *UprFeed) closeNodeFeeds() {
+	for _, f := range feed.nodeFeeds {
+		logging.Infof(" Sending close to forwardUprEvent ")
+		close(f.quit)
+		f.uprFeed.Close()
+	}
+	feed.nodeFeeds = nil
+}
+
+// Close a Upr feed.
+func (feed *UprFeed) Close() error {
+	select {
+	case <-feed.quit:
+		return nil
+	default:
+	}
+
+	feed.closing = true
+	feed.closeNodeFeeds()
+	close(feed.quit)
+
+	feed.wg.Wait()
+	if feed.outputClosed == false {
+		feed.outputClosed = true
+		close(feed.output)
+	}
+
+	return nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/users.go b/vendor/github.com/couchbaselabs/go-couchbase/users.go
new file mode 100644
index 0000000000..47d4861522
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/users.go
@@ -0,0 +1,119 @@
+package couchbase
+
+import (
+	"bytes"
+	"fmt"
+)
+
+type User struct {
+	Name   string
+	Id     string
+	Domain string
+	Roles  []Role
+}
+
+type Role struct {
+	Role       string
+	BucketName string `json:"bucket_name"`
+}
+
+// Sample:
+// {"role":"admin","name":"Admin","desc":"Can manage ALL cluster features including security.","ce":true}
+// {"role":"query_select","bucket_name":"*","name":"Query Select","desc":"Can execute SELECT statement on bucket to retrieve data"}
+type RoleDescription struct {
+	Role       string
+	Name       string
+	Desc       string
+	Ce         bool
+	BucketName string `json:"bucket_name"`
+}
+
+// Return user-role data, as parsed JSON.
+// Sample:
+//   [{"id":"ivanivanov","name":"Ivan Ivanov","roles":[{"role":"cluster_admin"},{"bucket_name":"default","role":"bucket_admin"}]},
+//    {"id":"petrpetrov","name":"Petr Petrov","roles":[{"role":"replication_admin"}]}]
+func (c *Client) GetUserRoles() ([]interface{}, error) {
+	ret := make([]interface{}, 0, 1)
+	err := c.parseURLResponse("/settings/rbac/users", &ret)
+	if err != nil {
+		return nil, err
+	}
+
+	// Get the configured administrator.
+	// Expected result: {"port":8091,"username":"Administrator"}
+	adminInfo := make(map[string]interface{}, 2)
+	err = c.parseURLResponse("/settings/web", &adminInfo)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create a special entry for the configured administrator.
+	adminResult := map[string]interface{}{
+		"name":   adminInfo["username"],
+		"id":     adminInfo["username"],
+		"domain": "ns_server",
+		"roles": []interface{}{
+			map[string]interface{}{
+				"role": "admin",
+			},
+		},
+	}
+
+	// Add the configured administrator to the list of results.
+	ret = append(ret, adminResult)
+
+	return ret, nil
+}
+
+func (c *Client) GetUserInfoAll() ([]User, error) {
+	ret := make([]User, 0, 16)
+	err := c.parseURLResponse("/settings/rbac/users", &ret)
+	if err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+func rolesToParamFormat(roles []Role) string {
+	var buffer bytes.Buffer
+	for i, role := range roles {
+		if i > 0 {
+			buffer.WriteString(",")
+		}
+		buffer.WriteString(role.Role)
+		if role.BucketName != "" {
+			buffer.WriteString("[")
+			buffer.WriteString(role.BucketName)
+			buffer.WriteString("]")
+		}
+	}
+	return buffer.String()
+}
+
+func (c *Client) PutUserInfo(u *User) error {
+	params := map[string]interface{}{
+		"name":  u.Name,
+		"roles": rolesToParamFormat(u.Roles),
+	}
+	var target string
+	switch u.Domain {
+	case "external":
+		target = "/settings/rbac/users/" + u.Id
+	case "local":
+		target = "/settings/rbac/users/local/" + u.Id
+	default:
+		return fmt.Errorf("Unknown user type: %s", u.Domain)
+	}
+	var ret string // PUT returns an empty string. We ignore it.
+	err := c.parsePutURLResponse(target, params, &ret)
+	return err
+}
+
+func (c *Client) GetRolesAll() ([]RoleDescription, error) {
+	ret := make([]RoleDescription, 0, 32)
+	err := c.parseURLResponse("/settings/rbac/roles", &ret)
+	if err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/util.go b/vendor/github.com/couchbaselabs/go-couchbase/util.go
new file mode 100644
index 0000000000..4d286a3271
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/util.go
@@ -0,0 +1,49 @@
+package couchbase
+
+import (
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+// CleanupHost returns the hostname with the given suffix removed.
+func CleanupHost(h, commonSuffix string) string {
+	if strings.HasSuffix(h, commonSuffix) {
+		return h[:len(h)-len(commonSuffix)]
+	}
+	return h
+}
+
+// FindCommonSuffix returns the longest common suffix from the given
+// strings.
+func FindCommonSuffix(input []string) string {
+	rv := ""
+	if len(input) < 2 {
+		return ""
+	}
+	from := input
+	for i := len(input[0]); i > 0; i-- {
+		common := true
+		suffix := input[0][i:]
+		for _, s := range from {
+			if !strings.HasSuffix(s, suffix) {
+				common = false
+				break
+			}
+		}
+		if common {
+			rv = suffix
+		}
+	}
+	return rv
+}
+
+// ParseURL is a wrapper around url.Parse with some sanity-checking
+func ParseURL(urlStr string) (result *url.URL, err error) {
+	result, err = url.Parse(urlStr)
+	if result != nil && result.Scheme == "" {
+		result = nil
+		err = fmt.Errorf("invalid URL <%s>", urlStr)
+	}
+	return
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/vbmap.go b/vendor/github.com/couchbaselabs/go-couchbase/vbmap.go
new file mode 100644
index 0000000000..b96a18ed57
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/vbmap.go
@@ -0,0 +1,77 @@
+package couchbase
+
+var crc32tab = []uint32{
+	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
+	0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+	0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
+	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+	0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
+	0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
+	0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+	0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
+	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+	0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
+	0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
+	0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+	0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
+	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+	0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
+	0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
+	0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+	0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
+	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+	0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
+	0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
+	0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+	0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
+	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+	0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
+	0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
+	0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+	0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
+	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+	0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
+	0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
+	0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+	0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
+	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+	0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
+	0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
+	0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+	0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
+	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+	0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
+	0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
+	0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+	0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
+	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+	0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
+	0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
+	0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+	0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
+	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+	0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
+	0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
+	0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+	0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
+	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d}
+
+// VBHash finds the vbucket for the given key.
+func (b *Bucket) VBHash(key string) uint32 {
+	crc := uint32(0xffffffff)
+	for x := 0; x < len(key); x++ {
+		crc = (crc >> 8) ^ crc32tab[(uint64(crc)^uint64(key[x]))&0xff]
+	}
+	vbm := b.VBServerMap()
+	return ((^crc) >> 16) & 0x7fff & (uint32(len(vbm.VBucketMap)) - 1)
+}
diff --git a/vendor/github.com/couchbaselabs/go-couchbase/views.go b/vendor/github.com/couchbaselabs/go-couchbase/views.go
new file mode 100644
index 0000000000..2f68642f5a
--- /dev/null
+++ b/vendor/github.com/couchbaselabs/go-couchbase/views.go
@@ -0,0 +1,231 @@
+package couchbase
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"math/rand"
+	"net/http"
+	"net/url"
+	"time"
+)
+
+// ViewRow represents a single result from a view.
+//
+// Doc is present only if include_docs was set on the request.
+type ViewRow struct {
+	ID    string
+	Key   interface{}
+	Value interface{}
+	Doc   *interface{}
+}
+
+// A ViewError is a node-specific error indicating a partial failure
+// within a view result.
+type ViewError struct {
+	From   string
+	Reason string
+}
+
+func (ve ViewError) Error() string {
+	return "Node: " + ve.From + ", reason: " + ve.Reason
+}
+
+// ViewResult holds the entire result set from a view request,
+// including the rows and the errors.
+type ViewResult struct {
+	TotalRows int `json:"total_rows"`
+	Rows      []ViewRow
+	Errors    []ViewError
+}
+
+func (b *Bucket) randomBaseURL() (*url.URL, error) {
+	nodes := b.HealthyNodes()
+	if len(nodes) == 0 {
+		return nil, errors.New("no available couch rest URLs")
+	}
+	nodeNo := rand.Intn(len(nodes))
+	node := nodes[nodeNo]
+
+	b.RLock()
+	name := b.Name
+	pool := b.pool
+	b.RUnlock()
+
+	u, err := ParseURL(node.CouchAPIBase)
+	if err != nil {
+		return nil, fmt.Errorf("config error: Bucket %q node #%d CouchAPIBase=%q: %v",
+			name, nodeNo, node.CouchAPIBase, err)
+	} else if pool != nil {
+		u.User = pool.client.BaseURL.User
+	}
+	return u, err
+}
+
+const START_NODE_ID = -1
+
+func (b *Bucket) randomNextURL(lastNode int) (*url.URL, int, error) {
+	nodes := b.HealthyNodes()
+	if len(nodes) == 0 {
+		return nil, -1, errors.New("no available couch rest URLs")
+	}
+
+	var nodeNo int
+	if lastNode == START_NODE_ID || lastNode >= len(nodes) {
+		// randomly select a node if the value of lastNode is invalid
+		nodeNo = rand.Intn(len(nodes))
+	} else {
+		// wrap around the node list
+		nodeNo = (lastNode + 1) % len(nodes)
+	}
+
+	b.RLock()
+	name := b.Name
+	pool := b.pool
+	b.RUnlock()
+
+	node := nodes[nodeNo]
+	u, err := ParseURL(node.CouchAPIBase)
+	if err != nil {
+		return nil, -1, fmt.Errorf("config error: Bucket %q node #%d CouchAPIBase=%q: %v",
+			name, nodeNo, node.CouchAPIBase, err)
+	} else if pool != nil {
+		u.User = pool.client.BaseURL.User
+	}
+	return u, nodeNo, err
+}
+
+// DocID is the document ID type for the startkey_docid parameter in
+// views.
+type DocID string
+
+func qParam(k, v string) string {
+	format := `"%s"`
+	switch k {
+	case "startkey_docid", "endkey_docid", "stale":
+		format = "%s"
+	}
+	return fmt.Sprintf(format, v)
+}
+
+// ViewURL constructs a URL for a view with the given ddoc, view name,
+// and parameters.
+func (b *Bucket) ViewURL(ddoc, name string,
+	params map[string]interface{}) (string, error) {
+	u, err := b.randomBaseURL()
+	if err != nil {
+		return "", err
+	}
+
+	values := url.Values{}
+	for k, v := range params {
+		switch t := v.(type) {
+		case DocID:
+			values[k] = []string{string(t)}
+		case string:
+			values[k] = []string{qParam(k, t)}
+		case int:
+			values[k] = []string{fmt.Sprintf(`%d`, t)}
+		case bool:
+			values[k] = []string{fmt.Sprintf(`%v`, t)}
+		default:
+			b, err := json.Marshal(v)
+			if err != nil {
+				return "", fmt.Errorf("unsupported value-type %T in Query, "+
+					"json encoder said %v", t, err)
+			}
+			values[k] = []string{fmt.Sprintf(`%v`, string(b))}
+		}
+	}
+
+	if ddoc == "" && name == "_all_docs" {
+		u.Path = fmt.Sprintf("/%s/_all_docs", b.GetName())
+	} else {
+		u.Path = fmt.Sprintf("/%s/_design/%s/_view/%s", b.GetName(), ddoc, name)
+	}
+	u.RawQuery = values.Encode()
+
+	return u.String(), nil
+}
+
+// ViewCallback is called for each view invocation.
+var ViewCallback func(ddoc, name string, start time.Time, err error)
+
+// ViewCustom performs a view request that can map row values to a
+// custom type.
+//
+// See the source to View for an example usage.
+func (b *Bucket) ViewCustom(ddoc, name string, params map[string]interface{},
+	vres interface{}) (err error) {
+	if SlowServerCallWarningThreshold > 0 {
+		defer slowLog(time.Now(), "call to ViewCustom(%q, %q)", ddoc, name)
+	}
+
+	if ViewCallback != nil {
+		defer func(t time.Time) { ViewCallback(ddoc, name, t, err) }(time.Now())
+	}
+
+	u, err := b.ViewURL(ddoc, name, params)
+	if err != nil {
+		return err
+	}
+
+	req, err := http.NewRequest("GET", u, nil)
+	if err != nil {
+		return err
+	}
+
+	ah := b.authHandler(false /* bucket not yet locked */)
+	maybeAddAuth(req, ah)
+
+	res, err := doHTTPRequest(req)
+	if err != nil {
+		return fmt.Errorf("error starting view req at %v: %v", u, err)
+	}
+	defer res.Body.Close()
+
+	if res.StatusCode != 200 {
+		bod := make([]byte, 512)
+		l, _ := res.Body.Read(bod)
+		return fmt.Errorf("error executing view req at %v: %v - %s",
+			u, res.Status, bod[:l])
+	}
+
+	body, err := ioutil.ReadAll(res.Body)
+	if err := json.Unmarshal(body, vres); err != nil {
+		return nil
+	}
+
+	return nil
+}
+
+// View executes a view.
+//
+// The ddoc parameter is just the bare name of your design doc without
+// the "_design/" prefix.
+//
+// Parameters are string keys with values that correspond to couchbase
+// view parameters.  Primitive should work fairly naturally (booleans,
+// ints, strings, etc...) and other values will attempt to be JSON
+// marshaled (useful for array indexing on on view keys, for example).
+//
+// Example:
+//
+//   res, err := couchbase.View("myddoc", "myview", map[string]interface{}{
+//       "group_level": 2,
+//       "startkey_docid":    []interface{}{"thing"},
+//       "endkey_docid":      []interface{}{"thing", map[string]string{}},
+//       "stale": false,
+//       })
+func (b *Bucket) View(ddoc, name string, params map[string]interface{}) (ViewResult, error) {
+	vres := ViewResult{}
+
+	if err := b.ViewCustom(ddoc, name, params, &vres); err != nil {
+		//error in accessing views. Retry once after a bucket refresh
+		b.Refresh()
+		return vres, b.ViewCustom(ddoc, name, params, &vres)
+	} else {
+		return vres, nil
+	}
+}
diff --git a/vendor/github.com/go-macaron/session/couchbase/couchbase.go b/vendor/github.com/go-macaron/session/couchbase/couchbase.go
new file mode 100644
index 0000000000..8001fd15f1
--- /dev/null
+++ b/vendor/github.com/go-macaron/session/couchbase/couchbase.go
@@ -0,0 +1,228 @@
+// Copyright 2013 Beego Authors
+// Copyright 2014 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+package session
+
+import (
+	"strings"
+	"sync"
+
+	"github.com/couchbaselabs/go-couchbase"
+
+	"github.com/go-macaron/session"
+)
+
+// CouchbaseSessionStore represents a couchbase session store implementation.
+type CouchbaseSessionStore struct {
+	b           *couchbase.Bucket
+	sid         string
+	lock        sync.RWMutex
+	data        map[interface{}]interface{}
+	maxlifetime int64
+}
+
+// Set sets value to given key in session.
+func (s *CouchbaseSessionStore) Set(key, val interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data[key] = val
+	return nil
+}
+
+// Get gets value by given key in session.
+func (s *CouchbaseSessionStore) Get(key interface{}) interface{} {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.data[key]
+}
+
+// Delete delete a key from session.
+func (s *CouchbaseSessionStore) Delete(key interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	delete(s.data, key)
+	return nil
+}
+
+// ID returns current session ID.
+func (s *CouchbaseSessionStore) ID() string {
+	return s.sid
+}
+
+// Release releases resource and save data to provider.
+func (s *CouchbaseSessionStore) Release() error {
+	defer s.b.Close()
+
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
+	data, err := session.EncodeGob(s.data)
+	if err != nil {
+		return err
+	}
+
+	return s.b.Set(s.sid, int(s.maxlifetime), data)
+}
+
+// Flush deletes all session data.
+func (s *CouchbaseSessionStore) Flush() error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data = make(map[interface{}]interface{})
+	return nil
+}
+
+// CouchbaseProvider represents a couchbase session provider implementation.
+type CouchbaseProvider struct {
+	maxlifetime int64
+	connStr     string
+	pool        string
+	bucket      string
+	b           *couchbase.Bucket
+}
+
+func (cp *CouchbaseProvider) getBucket() *couchbase.Bucket {
+	c, err := couchbase.Connect(cp.connStr)
+	if err != nil {
+		return nil
+	}
+
+	pool, err := c.GetPool(cp.pool)
+	if err != nil {
+		return nil
+	}
+
+	bucket, err := pool.GetBucket(cp.bucket)
+	if err != nil {
+		return nil
+	}
+
+	return bucket
+}
+
+// Init initializes memory session provider.
+// connStr is couchbase server REST/JSON URL
+// e.g. http://host:port/, Pool, Bucket
+func (p *CouchbaseProvider) Init(maxlifetime int64, connStr string) error {
+	p.maxlifetime = maxlifetime
+	configs := strings.Split(connStr, ",")
+	if len(configs) > 0 {
+		p.connStr = configs[0]
+	}
+	if len(configs) > 1 {
+		p.pool = configs[1]
+	}
+	if len(configs) > 2 {
+		p.bucket = configs[2]
+	}
+
+	return nil
+}
+
+// Read returns raw session store by session ID.
+func (p *CouchbaseProvider) Read(sid string) (session.RawStore, error) {
+	p.b = p.getBucket()
+
+	var doc []byte
+
+	err := p.b.Get(sid, &doc)
+	var kv map[interface{}]interface{}
+	if doc == nil {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(doc)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	cs := &CouchbaseSessionStore{b: p.b, sid: sid, data: kv, maxlifetime: p.maxlifetime}
+	return cs, nil
+}
+
+// Exist returns true if session with given ID exists.
+func (p *CouchbaseProvider) Exist(sid string) bool {
+	p.b = p.getBucket()
+	defer p.b.Close()
+
+	var doc []byte
+
+	if err := p.b.Get(sid, &doc); err != nil || doc == nil {
+		return false
+	} else {
+		return true
+	}
+}
+
+// Destory deletes a session by session ID.
+func (p *CouchbaseProvider) Destory(sid string) error {
+	p.b = p.getBucket()
+	defer p.b.Close()
+
+	p.b.Delete(sid)
+	return nil
+}
+
+// Regenerate regenerates a session store from old session ID to new one.
+func (p *CouchbaseProvider) Regenerate(oldsid, sid string) (session.RawStore, error) {
+	p.b = p.getBucket()
+
+	var doc []byte
+	if err := p.b.Get(oldsid, &doc); err != nil || doc == nil {
+		p.b.Set(sid, int(p.maxlifetime), "")
+	} else {
+		err := p.b.Delete(oldsid)
+		if err != nil {
+			return nil, err
+		}
+		_, _ = p.b.Add(sid, int(p.maxlifetime), doc)
+	}
+
+	err := p.b.Get(sid, &doc)
+	if err != nil {
+		return nil, err
+	}
+	var kv map[interface{}]interface{}
+	if doc == nil {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(doc)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	cs := &CouchbaseSessionStore{b: p.b, sid: sid, data: kv, maxlifetime: p.maxlifetime}
+	return cs, nil
+}
+
+// Count counts and returns number of sessions.
+func (p *CouchbaseProvider) Count() int {
+	// FIXME
+	return 0
+}
+
+// GC calls GC to clean expired sessions.
+func (p *CouchbaseProvider) GC() {}
+
+func init() {
+	session.Register("couchbase", &CouchbaseProvider{})
+}
diff --git a/vendor/github.com/go-macaron/session/file.go b/vendor/github.com/go-macaron/session/file.go
index 9bbc7aed20..64b47f2b00 100644
--- a/vendor/github.com/go-macaron/session/file.go
+++ b/vendor/github.com/go-macaron/session/file.go
@@ -81,6 +81,11 @@ func (s *FileStore) Release() error {
 	s.p.lock.Lock()
 	defer s.p.lock.Unlock()
 
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
 	data, err := EncodeGob(s.data)
 	if err != nil {
 		return err
diff --git a/vendor/github.com/go-macaron/session/flash.go b/vendor/github.com/go-macaron/session/flash.go
new file mode 100644
index 0000000000..99aae71e22
--- /dev/null
+++ b/vendor/github.com/go-macaron/session/flash.go
@@ -0,0 +1,61 @@
+// Copyright 2018 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+package session
+
+import (
+	"net/url"
+
+	"gopkg.in/macaron.v1"
+)
+
+type Flash struct {
+	ctx *macaron.Context
+	url.Values
+	ErrorMsg, WarningMsg, InfoMsg, SuccessMsg string
+}
+
+func (f *Flash) set(name, msg string, current ...bool) {
+	isShow := false
+	if (len(current) == 0 && macaron.FlashNow) ||
+		(len(current) > 0 && current[0]) {
+		isShow = true
+	}
+
+	if isShow {
+		f.ctx.Data["Flash"] = f
+	} else {
+		f.Set(name, msg)
+	}
+}
+
+func (f *Flash) Error(msg string, current ...bool) {
+	f.ErrorMsg = msg
+	f.set("error", msg, current...)
+}
+
+func (f *Flash) Warning(msg string, current ...bool) {
+	f.WarningMsg = msg
+	f.set("warning", msg, current...)
+}
+
+func (f *Flash) Info(msg string, current ...bool) {
+	f.InfoMsg = msg
+	f.set("info", msg, current...)
+}
+
+func (f *Flash) Success(msg string, current ...bool) {
+	f.SuccessMsg = msg
+	f.set("success", msg, current...)
+}
diff --git a/vendor/github.com/go-macaron/session/memcache/memcache.go b/vendor/github.com/go-macaron/session/memcache/memcache.go
new file mode 100644
index 0000000000..496939398b
--- /dev/null
+++ b/vendor/github.com/go-macaron/session/memcache/memcache.go
@@ -0,0 +1,204 @@
+// Copyright 2013 Beego Authors
+// Copyright 2014 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+package session
+
+import (
+	"fmt"
+	"strings"
+	"sync"
+
+	"github.com/bradfitz/gomemcache/memcache"
+
+	"github.com/go-macaron/session"
+)
+
+// MemcacheStore represents a memcache session store implementation.
+type MemcacheStore struct {
+	c      *memcache.Client
+	sid    string
+	expire int32
+	lock   sync.RWMutex
+	data   map[interface{}]interface{}
+}
+
+// NewMemcacheStore creates and returns a memcache session store.
+func NewMemcacheStore(c *memcache.Client, sid string, expire int32, kv map[interface{}]interface{}) *MemcacheStore {
+	return &MemcacheStore{
+		c:      c,
+		sid:    sid,
+		expire: expire,
+		data:   kv,
+	}
+}
+
+func NewItem(sid string, data []byte, expire int32) *memcache.Item {
+	return &memcache.Item{
+		Key:        sid,
+		Value:      data,
+		Expiration: expire,
+	}
+}
+
+// Set sets value to given key in session.
+func (s *MemcacheStore) Set(key, val interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data[key] = val
+	return nil
+}
+
+// Get gets value by given key in session.
+func (s *MemcacheStore) Get(key interface{}) interface{} {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.data[key]
+}
+
+// Delete delete a key from session.
+func (s *MemcacheStore) Delete(key interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	delete(s.data, key)
+	return nil
+}
+
+// ID returns current session ID.
+func (s *MemcacheStore) ID() string {
+	return s.sid
+}
+
+// Release releases resource and save data to provider.
+func (s *MemcacheStore) Release() error {
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
+	data, err := session.EncodeGob(s.data)
+	if err != nil {
+		return err
+	}
+
+	return s.c.Set(NewItem(s.sid, data, s.expire))
+}
+
+// Flush deletes all session data.
+func (s *MemcacheStore) Flush() error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data = make(map[interface{}]interface{})
+	return nil
+}
+
+// MemcacheProvider represents a memcache session provider implementation.
+type MemcacheProvider struct {
+	c      *memcache.Client
+	expire int32
+}
+
+// Init initializes memcache session provider.
+// connStrs: 127.0.0.1:9090;127.0.0.1:9091
+func (p *MemcacheProvider) Init(expire int64, connStrs string) error {
+	p.expire = int32(expire)
+	p.c = memcache.New(strings.Split(connStrs, ";")...)
+	return nil
+}
+
+// Read returns raw session store by session ID.
+func (p *MemcacheProvider) Read(sid string) (session.RawStore, error) {
+	if !p.Exist(sid) {
+		if err := p.c.Set(NewItem(sid, []byte(""), p.expire)); err != nil {
+			return nil, err
+		}
+	}
+
+	var kv map[interface{}]interface{}
+	item, err := p.c.Get(sid)
+	if err != nil {
+		return nil, err
+	}
+	if len(item.Value) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(item.Value)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewMemcacheStore(p.c, sid, p.expire, kv), nil
+}
+
+// Exist returns true if session with given ID exists.
+func (p *MemcacheProvider) Exist(sid string) bool {
+	_, err := p.c.Get(sid)
+	return err == nil
+}
+
+// Destory deletes a session by session ID.
+func (p *MemcacheProvider) Destory(sid string) error {
+	return p.c.Delete(sid)
+}
+
+// Regenerate regenerates a session store from old session ID to new one.
+func (p *MemcacheProvider) Regenerate(oldsid, sid string) (_ session.RawStore, err error) {
+	if p.Exist(sid) {
+		return nil, fmt.Errorf("new sid '%s' already exists", sid)
+	}
+
+	item := NewItem(sid, []byte(""), p.expire)
+	if p.Exist(oldsid) {
+		item, err = p.c.Get(oldsid)
+		if err != nil {
+			return nil, err
+		} else if err = p.c.Delete(oldsid); err != nil {
+			return nil, err
+		}
+		item.Key = sid
+	}
+	if err = p.c.Set(item); err != nil {
+		return nil, err
+	}
+
+	var kv map[interface{}]interface{}
+	if len(item.Value) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(item.Value)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewMemcacheStore(p.c, sid, p.expire, kv), nil
+}
+
+// Count counts and returns number of sessions.
+func (p *MemcacheProvider) Count() int {
+	// FIXME: how come this library does not have Stats method?
+	return -1
+}
+
+// GC calls GC to clean expired sessions.
+func (p *MemcacheProvider) GC() {}
+
+func init() {
+	session.Register("memcache", &MemcacheProvider{})
+}
diff --git a/vendor/github.com/go-macaron/session/mysql/mysql.go b/vendor/github.com/go-macaron/session/mysql/mysql.go
new file mode 100644
index 0000000000..7bde37445e
--- /dev/null
+++ b/vendor/github.com/go-macaron/session/mysql/mysql.go
@@ -0,0 +1,200 @@
+// Copyright 2013 Beego Authors
+// Copyright 2014 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+package session
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"sync"
+	"time"
+
+	_ "github.com/go-sql-driver/mysql"
+
+	"github.com/go-macaron/session"
+)
+
+// MysqlStore represents a mysql session store implementation.
+type MysqlStore struct {
+	c    *sql.DB
+	sid  string
+	lock sync.RWMutex
+	data map[interface{}]interface{}
+}
+
+// NewMysqlStore creates and returns a mysql session store.
+func NewMysqlStore(c *sql.DB, sid string, kv map[interface{}]interface{}) *MysqlStore {
+	return &MysqlStore{
+		c:    c,
+		sid:  sid,
+		data: kv,
+	}
+}
+
+// Set sets value to given key in session.
+func (s *MysqlStore) Set(key, val interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data[key] = val
+	return nil
+}
+
+// Get gets value by given key in session.
+func (s *MysqlStore) Get(key interface{}) interface{} {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.data[key]
+}
+
+// Delete delete a key from session.
+func (s *MysqlStore) Delete(key interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	delete(s.data, key)
+	return nil
+}
+
+// ID returns current session ID.
+func (s *MysqlStore) ID() string {
+	return s.sid
+}
+
+// Release releases resource and save data to provider.
+func (s *MysqlStore) Release() error {
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
+	data, err := session.EncodeGob(s.data)
+	if err != nil {
+		return err
+	}
+
+	_, err = s.c.Exec("UPDATE session SET data=?, expiry=? WHERE `key`=?",
+		data, time.Now().Unix(), s.sid)
+	return err
+}
+
+// Flush deletes all session data.
+func (s *MysqlStore) Flush() error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data = make(map[interface{}]interface{})
+	return nil
+}
+
+// MysqlProvider represents a mysql session provider implementation.
+type MysqlProvider struct {
+	c      *sql.DB
+	expire int64
+}
+
+// Init initializes mysql session provider.
+// connStr: username:password@protocol(address)/dbname?param=value
+func (p *MysqlProvider) Init(expire int64, connStr string) (err error) {
+	p.expire = expire
+
+	p.c, err = sql.Open("mysql", connStr)
+	if err != nil {
+		return err
+	}
+	return p.c.Ping()
+}
+
+// Read returns raw session store by session ID.
+func (p *MysqlProvider) Read(sid string) (session.RawStore, error) {
+	var data []byte
+	err := p.c.QueryRow("SELECT data FROM session WHERE `key`=?", sid).Scan(&data)
+	if err == sql.ErrNoRows {
+		_, err = p.c.Exec("INSERT INTO session(`key`,data,expiry) VALUES(?,?,?)",
+			sid, "", time.Now().Unix())
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	var kv map[interface{}]interface{}
+	if len(data) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(data)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewMysqlStore(p.c, sid, kv), nil
+}
+
+// Exist returns true if session with given ID exists.
+func (p *MysqlProvider) Exist(sid string) bool {
+	var data []byte
+	err := p.c.QueryRow("SELECT data FROM session WHERE `key`=?", sid).Scan(&data)
+	if err != nil && err != sql.ErrNoRows {
+		panic("session/mysql: error checking existence: " + err.Error())
+	}
+	return err != sql.ErrNoRows
+}
+
+// Destory deletes a session by session ID.
+func (p *MysqlProvider) Destory(sid string) error {
+	_, err := p.c.Exec("DELETE FROM session WHERE `key`=?", sid)
+	return err
+}
+
+// Regenerate regenerates a session store from old session ID to new one.
+func (p *MysqlProvider) Regenerate(oldsid, sid string) (_ session.RawStore, err error) {
+	if p.Exist(sid) {
+		return nil, fmt.Errorf("new sid '%s' already exists", sid)
+	}
+
+	if !p.Exist(oldsid) {
+		if _, err = p.c.Exec("INSERT INTO session(`key`,data,expiry) VALUES(?,?,?)",
+			oldsid, "", time.Now().Unix()); err != nil {
+			return nil, err
+		}
+	}
+
+	if _, err = p.c.Exec("UPDATE session SET `key`=? WHERE `key`=?", sid, oldsid); err != nil {
+		return nil, err
+	}
+
+	return p.Read(sid)
+}
+
+// Count counts and returns number of sessions.
+func (p *MysqlProvider) Count() (total int) {
+	if err := p.c.QueryRow("SELECT COUNT(*) AS NUM FROM session").Scan(&total); err != nil {
+		panic("session/mysql: error counting records: " + err.Error())
+	}
+	return total
+}
+
+// GC calls GC to clean expired sessions.
+func (p *MysqlProvider) GC() {
+	if _, err := p.c.Exec("DELETE FROM session WHERE  expiry + ? <= UNIX_TIMESTAMP(NOW())", p.expire); err != nil {
+		log.Printf("session/mysql: error garbage collecting: %v", err)
+	}
+}
+
+func init() {
+	session.Register("mysql", &MysqlProvider{})
+}
diff --git a/vendor/github.com/go-macaron/session/nodb/nodb.go b/vendor/github.com/go-macaron/session/nodb/nodb.go
new file mode 100644
index 0000000000..8b5a711693
--- /dev/null
+++ b/vendor/github.com/go-macaron/session/nodb/nodb.go
@@ -0,0 +1,208 @@
+// Copyright 2015 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+package session
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/lunny/nodb"
+	"github.com/lunny/nodb/config"
+
+	"github.com/go-macaron/session"
+)
+
+// NodbStore represents a nodb session store implementation.
+type NodbStore struct {
+	c      *nodb.DB
+	sid    string
+	expire int64
+	lock   sync.RWMutex
+	data   map[interface{}]interface{}
+}
+
+// NewNodbStore creates and returns a ledis session store.
+func NewNodbStore(c *nodb.DB, sid string, expire int64, kv map[interface{}]interface{}) *NodbStore {
+	return &NodbStore{
+		c:      c,
+		expire: expire,
+		sid:    sid,
+		data:   kv,
+	}
+}
+
+// Set sets value to given key in session.
+func (s *NodbStore) Set(key, val interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data[key] = val
+	return nil
+}
+
+// Get gets value by given key in session.
+func (s *NodbStore) Get(key interface{}) interface{} {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.data[key]
+}
+
+// Delete delete a key from session.
+func (s *NodbStore) Delete(key interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	delete(s.data, key)
+	return nil
+}
+
+// ID returns current session ID.
+func (s *NodbStore) ID() string {
+	return s.sid
+}
+
+// Release releases resource and save data to provider.
+func (s *NodbStore) Release() error {
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
+	data, err := session.EncodeGob(s.data)
+	if err != nil {
+		return err
+	}
+
+	if err = s.c.Set([]byte(s.sid), data); err != nil {
+		return err
+	}
+	_, err = s.c.Expire([]byte(s.sid), s.expire)
+	return err
+}
+
+// Flush deletes all session data.
+func (s *NodbStore) Flush() error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data = make(map[interface{}]interface{})
+	return nil
+}
+
+// NodbProvider represents a ledis session provider implementation.
+type NodbProvider struct {
+	c      *nodb.DB
+	expire int64
+}
+
+// Init initializes nodb session provider.
+func (p *NodbProvider) Init(expire int64, configs string) error {
+	p.expire = expire
+
+	cfg := new(config.Config)
+	cfg.DataDir = configs
+	dbs, err := nodb.Open(cfg)
+	if err != nil {
+		return fmt.Errorf("session/nodb: error opening db: %v", err)
+	}
+
+	p.c, err = dbs.Select(0)
+	return err
+}
+
+// Read returns raw session store by session ID.
+func (p *NodbProvider) Read(sid string) (session.RawStore, error) {
+	if !p.Exist(sid) {
+		if err := p.c.Set([]byte(sid), []byte("")); err != nil {
+			return nil, err
+		}
+	}
+
+	var kv map[interface{}]interface{}
+	kvs, err := p.c.Get([]byte(sid))
+	if err != nil {
+		return nil, err
+	}
+	if len(kvs) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(kvs)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewNodbStore(p.c, sid, p.expire, kv), nil
+}
+
+// Exist returns true if session with given ID exists.
+func (p *NodbProvider) Exist(sid string) bool {
+	count, err := p.c.Exists([]byte(sid))
+	return err == nil && count > 0
+}
+
+// Destory deletes a session by session ID.
+func (p *NodbProvider) Destory(sid string) error {
+	_, err := p.c.Del([]byte(sid))
+	return err
+}
+
+// Regenerate regenerates a session store from old session ID to new one.
+func (p *NodbProvider) Regenerate(oldsid, sid string) (_ session.RawStore, err error) {
+	if p.Exist(sid) {
+		return nil, fmt.Errorf("new sid '%s' already exists", sid)
+	}
+
+	kvs := make([]byte, 0)
+	if p.Exist(oldsid) {
+		if kvs, err = p.c.Get([]byte(oldsid)); err != nil {
+			return nil, err
+		} else if _, err = p.c.Del([]byte(oldsid)); err != nil {
+			return nil, err
+		}
+	}
+
+	if err = p.c.Set([]byte(sid), kvs); err != nil {
+		return nil, err
+	} else if _, err = p.c.Expire([]byte(sid), p.expire); err != nil {
+		return nil, err
+	}
+
+	var kv map[interface{}]interface{}
+	if len(kvs) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob([]byte(kvs))
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewNodbStore(p.c, sid, p.expire, kv), nil
+}
+
+// Count counts and returns number of sessions.
+func (p *NodbProvider) Count() int {
+	// FIXME: how come this library does not have DbSize() method?
+	return -1
+}
+
+// GC calls GC to clean expired sessions.
+func (p *NodbProvider) GC() {}
+
+func init() {
+	session.Register("nodb", &NodbProvider{})
+}
diff --git a/vendor/github.com/go-macaron/session/postgres/postgres.go b/vendor/github.com/go-macaron/session/postgres/postgres.go
new file mode 100644
index 0000000000..f1e034b501
--- /dev/null
+++ b/vendor/github.com/go-macaron/session/postgres/postgres.go
@@ -0,0 +1,201 @@
+// Copyright 2013 Beego Authors
+// Copyright 2014 The Macaron Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License"): you may
+// not use this file except in compliance with the License. You may obtain
+// a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+// License for the specific language governing permissions and limitations
+// under the License.
+
+package session
+
+import (
+	"database/sql"
+	"fmt"
+	"log"
+	"sync"
+	"time"
+
+	_ "github.com/lib/pq"
+
+	"github.com/go-macaron/session"
+)
+
+// PostgresStore represents a postgres session store implementation.
+type PostgresStore struct {
+	c    *sql.DB
+	sid  string
+	lock sync.RWMutex
+	data map[interface{}]interface{}
+}
+
+// NewPostgresStore creates and returns a postgres session store.
+func NewPostgresStore(c *sql.DB, sid string, kv map[interface{}]interface{}) *PostgresStore {
+	return &PostgresStore{
+		c:    c,
+		sid:  sid,
+		data: kv,
+	}
+}
+
+// Set sets value to given key in session.
+func (s *PostgresStore) Set(key, value interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data[key] = value
+	return nil
+}
+
+// Get gets value by given key in session.
+func (s *PostgresStore) Get(key interface{}) interface{} {
+	s.lock.RLock()
+	defer s.lock.RUnlock()
+
+	return s.data[key]
+}
+
+// Delete delete a key from session.
+func (s *PostgresStore) Delete(key interface{}) error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	delete(s.data, key)
+	return nil
+}
+
+// ID returns current session ID.
+func (s *PostgresStore) ID() string {
+	return s.sid
+}
+
+// save postgres session values to database.
+// must call this method to save values to database.
+func (s *PostgresStore) Release() error {
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
+	data, err := session.EncodeGob(s.data)
+	if err != nil {
+		return err
+	}
+
+	_, err = s.c.Exec("UPDATE session SET data=$1, expiry=$2 WHERE key=$3",
+		data, time.Now().Unix(), s.sid)
+	return err
+}
+
+// Flush deletes all session data.
+func (s *PostgresStore) Flush() error {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.data = make(map[interface{}]interface{})
+	return nil
+}
+
+// PostgresProvider represents a postgres session provider implementation.
+type PostgresProvider struct {
+	c           *sql.DB
+	maxlifetime int64
+}
+
+// Init initializes postgres session provider.
+// connStr: user=a password=b host=localhost port=5432 dbname=c sslmode=disable
+func (p *PostgresProvider) Init(maxlifetime int64, connStr string) (err error) {
+	p.maxlifetime = maxlifetime
+
+	p.c, err = sql.Open("postgres", connStr)
+	if err != nil {
+		return err
+	}
+	return p.c.Ping()
+}
+
+// Read returns raw session store by session ID.
+func (p *PostgresProvider) Read(sid string) (session.RawStore, error) {
+	var data []byte
+	err := p.c.QueryRow("SELECT data FROM session WHERE key=$1", sid).Scan(&data)
+	if err == sql.ErrNoRows {
+		_, err = p.c.Exec("INSERT INTO session(key,data,expiry) VALUES($1,$2,$3)",
+			sid, "", time.Now().Unix())
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	var kv map[interface{}]interface{}
+	if len(data) == 0 {
+		kv = make(map[interface{}]interface{})
+	} else {
+		kv, err = session.DecodeGob(data)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return NewPostgresStore(p.c, sid, kv), nil
+}
+
+// Exist returns true if session with given ID exists.
+func (p *PostgresProvider) Exist(sid string) bool {
+	var data []byte
+	err := p.c.QueryRow("SELECT data FROM session WHERE key=$1", sid).Scan(&data)
+	if err != nil && err != sql.ErrNoRows {
+		panic("session/postgres: error checking existence: " + err.Error())
+	}
+	return err != sql.ErrNoRows
+}
+
+// Destory deletes a session by session ID.
+func (p *PostgresProvider) Destory(sid string) error {
+	_, err := p.c.Exec("DELETE FROM session WHERE key=$1", sid)
+	return err
+}
+
+// Regenerate regenerates a session store from old session ID to new one.
+func (p *PostgresProvider) Regenerate(oldsid, sid string) (_ session.RawStore, err error) {
+	if p.Exist(sid) {
+		return nil, fmt.Errorf("new sid '%s' already exists", sid)
+	}
+
+	if !p.Exist(oldsid) {
+		if _, err = p.c.Exec("INSERT INTO session(key,data,expiry) VALUES($1,$2,$3)",
+			oldsid, "", time.Now().Unix()); err != nil {
+			return nil, err
+		}
+	}
+
+	if _, err = p.c.Exec("UPDATE session SET key=$1 WHERE key=$2", sid, oldsid); err != nil {
+		return nil, err
+	}
+
+	return p.Read(sid)
+}
+
+// Count counts and returns number of sessions.
+func (p *PostgresProvider) Count() (total int) {
+	if err := p.c.QueryRow("SELECT COUNT(*) AS NUM FROM session").Scan(&total); err != nil {
+		panic("session/postgres: error counting records: " + err.Error())
+	}
+	return total
+}
+
+// GC calls GC to clean expired sessions.
+func (p *PostgresProvider) GC() {
+	if _, err := p.c.Exec("DELETE FROM session WHERE EXTRACT(EPOCH FROM NOW()) - expiry > $1", p.maxlifetime); err != nil {
+		log.Printf("session/postgres: error garbage collecting: %v", err)
+	}
+}
+
+func init() {
+	session.Register("postgres", &PostgresProvider{})
+}
diff --git a/vendor/github.com/go-macaron/session/redis/redis.go b/vendor/github.com/go-macaron/session/redis/redis.go
index ca1cf88de6..2d7fe98405 100644
--- a/vendor/github.com/go-macaron/session/redis/redis.go
+++ b/vendor/github.com/go-macaron/session/redis/redis.go
@@ -81,6 +81,11 @@ func (s *RedisStore) ID() string {
 
 // Release releases resource and save data to provider.
 func (s *RedisStore) Release() error {
+	// Skip encoding if the data is empty
+	if len(s.data) == 0 {
+		return nil
+	}
+
 	data, err := session.EncodeGob(s.data)
 	if err != nil {
 		return err
@@ -153,7 +158,7 @@ func (p *RedisProvider) Init(maxlifetime int64, configs string) (err error) {
 func (p *RedisProvider) Read(sid string) (session.RawStore, error) {
 	psid := p.prefix + sid
 	if !p.Exist(sid) {
-		if err := p.c.Set(psid, "").Err(); err != nil {
+		if err := p.c.SetEx(psid, p.duration, "").Err(); err != nil {
 			return nil, err
 		}
 	}
diff --git a/vendor/github.com/go-macaron/session/session.go b/vendor/github.com/go-macaron/session/session.go
index d9bbae2032..97fa56ede6 100644
--- a/vendor/github.com/go-macaron/session/session.go
+++ b/vendor/github.com/go-macaron/session/session.go
@@ -22,13 +22,12 @@ import (
 	"fmt"
 	"net/http"
 	"net/url"
-	"strings"
 	"time"
 
 	"gopkg.in/macaron.v1"
 )
 
-const _VERSION = "0.4.0"
+const _VERSION = "0.6.0"
 
 func Version() string {
 	return _VERSION
@@ -96,6 +95,8 @@ type Options struct {
 	IDLength int
 	// Configuration section name. Default is "session".
 	Section string
+	// Ignore release for websocket. Default is false.
+	IgnoreReleaseForWebSocket bool
 }
 
 func prepareOptions(options []Options) Options {
@@ -138,6 +139,9 @@ func prepareOptions(options []Options) Options {
 	if opt.IDLength == 0 {
 		opt.IDLength = sec.Key("ID_LENGTH").MustInt(16)
 	}
+	if !opt.IgnoreReleaseForWebSocket {
+		opt.IgnoreReleaseForWebSocket = sec.Key("IGNORE_RELEASE_FOR_WEBSOCKET").MustBool()
+	}
 
 	return opt
 }
@@ -187,6 +191,10 @@ func Sessioner(options ...Options) macaron.Handler {
 
 		ctx.Next()
 
+		if manager.opt.IgnoreReleaseForWebSocket && ctx.Req.Header.Get("Upgrade") == "websocket" {
+			return
+		}
+
 		if err = sess.Release(); err != nil {
 			panic("session(release): " + err.Error())
 		}
@@ -252,12 +260,30 @@ func (m *Manager) sessionID() string {
 	return hex.EncodeToString(generateRandomKey(m.opt.IDLength / 2))
 }
 
+// validSessionID tests whether a provided session ID is a valid session ID.
+func (m *Manager) validSessionID(sid string) (bool, error) {
+	if len(sid) != m.opt.IDLength {
+		return false, errors.New("invalid 'sid': " + sid)
+	}
+
+	for i := range sid {
+		switch {
+		case '0' <= sid[i] && sid[i] <= '9':
+		case 'a' <= sid[i] && sid[i] <= 'f':
+		default:
+			return false, errors.New("invalid 'sid': " + sid)
+		}
+	}
+	return true, nil
+}
+
 // Start starts a session by generating new one
 // or retrieve existence one by reading session ID from HTTP request if it's valid.
 func (m *Manager) Start(ctx *macaron.Context) (RawStore, error) {
 	sid := ctx.GetCookie(m.opt.CookieName)
-	if len(sid) > 0 && m.provider.Exist(sid) {
-		return m.Read(sid)
+	valid, _ := m.validSessionID(sid)
+	if len(sid) > 0 && valid && m.provider.Exist(sid) {
+		return m.provider.Read(sid)
 	}
 
 	sid = m.sessionID()
@@ -284,10 +310,9 @@ func (m *Manager) Start(ctx *macaron.Context) (RawStore, error) {
 
 // Read returns raw session store by session ID.
 func (m *Manager) Read(sid string) (RawStore, error) {
-	// No slashes or dots "./" should ever occur in the sid and to prevent session file forgery bug.
-	// See https://github.com/gogs/gogs/issues/5469
-	if strings.ContainsAny(sid, "./") {
-		return nil, errors.New("invalid 'sid': " + sid)
+	// Ensure we're trying to read a valid session ID
+	if _, err := m.validSessionID(sid); err != nil {
+		return nil, err
 	}
 
 	return m.provider.Read(sid)
@@ -300,6 +325,10 @@ func (m *Manager) Destory(ctx *macaron.Context) error {
 		return nil
 	}
 
+	if _, err := m.validSessionID(sid); err != nil {
+		return err
+	}
+
 	if err := m.provider.Destory(sid); err != nil {
 		return err
 	}
@@ -318,11 +347,15 @@ func (m *Manager) Destory(ctx *macaron.Context) error {
 func (m *Manager) RegenerateId(ctx *macaron.Context) (sess RawStore, err error) {
 	sid := m.sessionID()
 	oldsid := ctx.GetCookie(m.opt.CookieName)
+	_, err = m.validSessionID(oldsid)
+	if err != nil {
+		return nil, err
+	}
 	sess, err = m.provider.Regenerate(oldsid, sid)
 	if err != nil {
 		return nil, err
 	}
-	ck := &http.Cookie{
+	cookie := &http.Cookie{
 		Name:     m.opt.CookieName,
 		Value:    sid,
 		Path:     m.opt.CookiePath,
@@ -331,10 +364,10 @@ func (m *Manager) RegenerateId(ctx *macaron.Context) (sess RawStore, err error)
 		Domain:   m.opt.Domain,
 	}
 	if m.opt.CookieLifeTime >= 0 {
-		ck.MaxAge = m.opt.CookieLifeTime
+		cookie.MaxAge = m.opt.CookieLifeTime
 	}
-	http.SetCookie(ctx.Resp, ck)
-	ctx.Req.AddCookie(ck)
+	http.SetCookie(ctx.Resp, cookie)
+	ctx.Req.AddCookie(cookie)
 	return sess, nil
 }
 
@@ -358,50 +391,3 @@ func (m *Manager) startGC() {
 func (m *Manager) SetSecure(secure bool) {
 	m.opt.Secure = secure
 }
-
-// ___________.____       _____    _________ ___ ___
-// \_   _____/|    |     /  _  \  /   _____//   |   \
-//  |    __)  |    |    /  /_\  \ \_____  \/    ~    \
-//  |     \   |    |___/    |    \/        \    Y    /
-//  \___  /   |_______ \____|__  /_______  /\___|_  /
-//      \/            \/       \/        \/       \/
-
-type Flash struct {
-	ctx *macaron.Context
-	url.Values
-	ErrorMsg, WarningMsg, InfoMsg, SuccessMsg string
-}
-
-func (f *Flash) set(name, msg string, current ...bool) {
-	isShow := false
-	if (len(current) == 0 && macaron.FlashNow) ||
-		(len(current) > 0 && current[0]) {
-		isShow = true
-	}
-
-	if isShow {
-		f.ctx.Data["Flash"] = f
-	} else {
-		f.Set(name, msg)
-	}
-}
-
-func (f *Flash) Error(msg string, current ...bool) {
-	f.ErrorMsg = msg
-	f.set("error", msg, current...)
-}
-
-func (f *Flash) Warning(msg string, current ...bool) {
-	f.WarningMsg = msg
-	f.set("warning", msg, current...)
-}
-
-func (f *Flash) Info(msg string, current ...bool) {
-	f.InfoMsg = msg
-	f.set("info", msg, current...)
-}
-
-func (f *Flash) Success(msg string, current ...bool) {
-	f.SuccessMsg = msg
-	f.set("success", msg, current...)
-}
diff --git a/vendor/github.com/go-macaron/session/utils.go b/vendor/github.com/go-macaron/session/utils.go
index 07a1283df9..90ca38064b 100644
--- a/vendor/github.com/go-macaron/session/utils.go
+++ b/vendor/github.com/go-macaron/session/utils.go
@@ -50,11 +50,14 @@ func DecodeGob(encoded []byte) (out map[interface{}]interface{}, err error) {
 	return out, err
 }
 
+// NOTE: A local copy in case of underlying package change
+var alphanum = []byte("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz")
+
 // generateRandomKey creates a random key with the given strength.
 func generateRandomKey(strength int) []byte {
 	k := make([]byte, strength)
 	if n, err := io.ReadFull(rand.Reader, k); n != strength || err != nil {
-		return com.RandomCreateBytes(strength)
+		return com.RandomCreateBytes(strength, alphanum...)
 	}
 	return k
 }
diff --git a/vendor/github.com/lunny/log/LICENSE b/vendor/github.com/lunny/log/LICENSE
new file mode 100644
index 0000000000..c9338f8293
--- /dev/null
+++ b/vendor/github.com/lunny/log/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2014 - 2016 lunny
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of the {organization} nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/lunny/log/dbwriter.go b/vendor/github.com/lunny/log/dbwriter.go
new file mode 100644
index 0000000000..e8ff00bd89
--- /dev/null
+++ b/vendor/github.com/lunny/log/dbwriter.go
@@ -0,0 +1,36 @@
+package log
+
+import (
+	"database/sql"
+	"time"
+)
+
+type DBWriter struct {
+	db      *sql.DB
+	stmt    *sql.Stmt
+	content chan []byte
+}
+
+func NewDBWriter(db *sql.DB) (*DBWriter, error) {
+	_, err := db.Exec("CREATE TABLE IF NOT EXISTS log (id int, content text, created datetime)")
+	if err != nil {
+		return nil, err
+	}
+	stmt, err := db.Prepare("INSERT INTO log (content, created) values (?, ?)")
+	if err != nil {
+		return nil, err
+	}
+	return &DBWriter{db, stmt, make(chan []byte, 1000)}, nil
+}
+
+func (w *DBWriter) Write(p []byte) (n int, err error) {
+	_, err = w.stmt.Exec(string(p), time.Now())
+	if err == nil {
+		n = len(p)
+	}
+	return
+}
+
+func (w *DBWriter) Close() {
+	w.stmt.Close()
+}
diff --git a/vendor/github.com/lunny/log/filewriter.go b/vendor/github.com/lunny/log/filewriter.go
new file mode 100644
index 0000000000..f0bb4d1df1
--- /dev/null
+++ b/vendor/github.com/lunny/log/filewriter.go
@@ -0,0 +1,112 @@
+package log
+
+import (
+	"io"
+	"os"
+	"path/filepath"
+	"sync"
+	"time"
+)
+
+var _ io.Writer = &Files{}
+
+type ByType int
+
+const (
+	ByDay ByType = iota
+	ByHour
+	ByMonth
+)
+
+var (
+	formats = map[ByType]string{
+		ByDay:   "2006-01-02",
+		ByHour:  "2006-01-02-15",
+		ByMonth: "2006-01",
+	}
+)
+
+func SetFileFormat(t ByType, format string) {
+	formats[t] = format
+}
+
+func (b ByType) Format() string {
+	return formats[b]
+}
+
+type Files struct {
+	FileOptions
+	f          *os.File
+	lastFormat string
+	lock       sync.Mutex
+}
+
+type FileOptions struct {
+	Dir    string
+	ByType ByType
+	Loc    *time.Location
+}
+
+func prepareFileOption(opts []FileOptions) FileOptions {
+	var opt FileOptions
+	if len(opts) > 0 {
+		opt = opts[0]
+	}
+	if opt.Dir == "" {
+		opt.Dir = "./"
+	}
+	err := os.MkdirAll(opt.Dir, os.ModePerm)
+	if err != nil {
+		panic(err.Error())
+	}
+
+	if opt.Loc == nil {
+		opt.Loc = time.Local
+	}
+	return opt
+}
+
+func NewFileWriter(opts ...FileOptions) *Files {
+	opt := prepareFileOption(opts)
+	return &Files{
+		FileOptions: opt,
+	}
+}
+
+func (f *Files) getFile() (*os.File, error) {
+	var err error
+	t := time.Now().In(f.Loc)
+	if f.f == nil {
+		f.lastFormat = t.Format(f.ByType.Format())
+		f.f, err = os.OpenFile(filepath.Join(f.Dir, f.lastFormat+".log"),
+			os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
+		return f.f, err
+	}
+	if f.lastFormat != t.Format(f.ByType.Format()) {
+		f.f.Close()
+		f.lastFormat = t.Format(f.ByType.Format())
+		f.f, err = os.OpenFile(filepath.Join(f.Dir, f.lastFormat+".log"),
+			os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
+		return f.f, err
+	}
+	return f.f, nil
+}
+
+func (f *Files) Write(bs []byte) (int, error) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	w, err := f.getFile()
+	if err != nil {
+		return 0, err
+	}
+	return w.Write(bs)
+}
+
+func (f *Files) Close() {
+	if f.f != nil {
+		f.f.Close()
+		f.f = nil
+	}
+	f.lastFormat = ""
+}
diff --git a/vendor/github.com/lunny/log/logext.go b/vendor/github.com/lunny/log/logext.go
new file mode 100644
index 0000000000..215c45f309
--- /dev/null
+++ b/vendor/github.com/lunny/log/logext.go
@@ -0,0 +1,595 @@
+package log
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"strings"
+	"sync"
+	"time"
+)
+
+// These flags define which text to prefix to each log entry generated by the Logger.
+const (
+	// Bits or'ed together to control what's printed. There is no control over the
+	// order they appear (the order listed here) or the format they present (as
+	// described in the comments).  A colon appears after these items:
+	//	2009/0123 01:23:23.123123 /a/b/c/d.go:23: message
+	Ldate         = 1 << iota     // the date: 2009/0123
+	Ltime                         // the time: 01:23:23
+	Lmicroseconds                 // microsecond resolution: 01:23:23.123123.  assumes Ltime.
+	Llongfile                     // full file name and line number: /a/b/c/d.go:23
+	Lshortfile                    // final file name element and line number: d.go:23. overrides Llongfile
+	Lmodule                       // module name
+	Llevel                        // level: 0(Debug), 1(Info), 2(Warn), 3(Error), 4(Panic), 5(Fatal)
+	Llongcolor                    // color will start [info] end of line
+	Lshortcolor                   // color only include [info]
+	LstdFlags     = Ldate | Ltime // initial values for the standard logger
+	//Ldefault      = Llevel | LstdFlags | Lshortfile | Llongcolor
+) // [prefix][time][level][module][shortfile|longfile]
+
+func Ldefault() int {
+	if runtime.GOOS == "windows" {
+		return Llevel | LstdFlags | Lshortfile
+	}
+	return Llevel | LstdFlags | Lshortfile | Llongcolor
+}
+
+func Version() string {
+	return "0.2.0.1121"
+}
+
+const (
+	Lall = iota
+)
+const (
+	Ldebug = iota
+	Linfo
+	Lwarn
+	Lerror
+	Lpanic
+	Lfatal
+	Lnone
+)
+
+const (
+	ForeBlack  = iota + 30 //30
+	ForeRed                //31
+	ForeGreen              //32
+	ForeYellow             //33
+	ForeBlue               //34
+	ForePurple             //35
+	ForeCyan               //36
+	ForeWhite              //37
+)
+
+const (
+	BackBlack  = iota + 40 //40
+	BackRed                //41
+	BackGreen              //42
+	BackYellow             //43
+	BackBlue               //44
+	BackPurple             //45
+	BackCyan               //46
+	BackWhite              //47
+)
+
+var levels = []string{
+	"[Debug]",
+	"[Info]",
+	"[Warn]",
+	"[Error]",
+	"[Panic]",
+	"[Fatal]",
+}
+
+// MUST called before all logs
+func SetLevels(lvs []string) {
+	levels = lvs
+}
+
+var colors = []int{
+	ForeCyan,
+	ForeGreen,
+	ForeYellow,
+	ForeRed,
+	ForePurple,
+	ForeBlue,
+}
+
+// MUST called before all logs
+func SetColors(cls []int) {
+	colors = cls
+}
+
+// A Logger represents an active logging object that generates lines of
+// output to an io.Writer.  Each logging operation makes a single call to
+// the Writer's Write method.  A Logger can be used simultaneously from
+// multiple goroutines; it guarantees to serialize access to the Writer.
+type Logger struct {
+	mu         sync.Mutex // ensures atomic writes; protects the following fields
+	prefix     string     // prefix to write at beginning of each line
+	flag       int        // properties
+	Level      int
+	out        io.Writer    // destination for output
+	buf        bytes.Buffer // for accumulating text to write
+	levelStats [6]int64
+	loc        *time.Location
+}
+
+// New creates a new Logger.   The out variable sets the
+// destination to which log data will be written.
+// The prefix appears at the beginning of each generated log line.
+// The flag argument defines the logging properties.
+func New(out io.Writer, prefix string, flag int) *Logger {
+	l := &Logger{out: out, prefix: prefix, Level: 1, flag: flag, loc: time.Local}
+	if out != os.Stdout {
+		l.flag = RmColorFlags(l.flag)
+	}
+	return l
+}
+
+var Std = New(os.Stderr, "", Ldefault())
+
+// Cheap integer to fixed-width decimal ASCII.  Give a negative width to avoid zero-padding.
+// Knows the buffer has capacity.
+func itoa(buf *bytes.Buffer, i int, wid int) {
+	var u uint = uint(i)
+	if u == 0 && wid <= 1 {
+		buf.WriteByte('0')
+		return
+	}
+
+	// Assemble decimal in reverse order.
+	var b [32]byte
+	bp := len(b)
+	for ; u > 0 || wid > 0; u /= 10 {
+		bp--
+		wid--
+		b[bp] = byte(u%10) + '0'
+	}
+
+	// avoid slicing b to avoid an allocation.
+	for bp < len(b) {
+		buf.WriteByte(b[bp])
+		bp++
+	}
+}
+
+func moduleOf(file string) string {
+	pos := strings.LastIndex(file, "/")
+	if pos != -1 {
+		pos1 := strings.LastIndex(file[:pos], "/src/")
+		if pos1 != -1 {
+			return file[pos1+5 : pos]
+		}
+	}
+	return "UNKNOWN"
+}
+
+func (l *Logger) formatHeader(buf *bytes.Buffer, t time.Time,
+	file string, line int, lvl int, reqId string) {
+	if l.prefix != "" {
+		buf.WriteString(l.prefix)
+	}
+	if l.flag&(Ldate|Ltime|Lmicroseconds) != 0 {
+		if l.flag&Ldate != 0 {
+			year, month, day := t.Date()
+			itoa(buf, year, 4)
+			buf.WriteByte('/')
+			itoa(buf, int(month), 2)
+			buf.WriteByte('/')
+			itoa(buf, day, 2)
+			buf.WriteByte(' ')
+		}
+		if l.flag&(Ltime|Lmicroseconds) != 0 {
+			hour, min, sec := t.Clock()
+			itoa(buf, hour, 2)
+			buf.WriteByte(':')
+			itoa(buf, min, 2)
+			buf.WriteByte(':')
+			itoa(buf, sec, 2)
+			if l.flag&Lmicroseconds != 0 {
+				buf.WriteByte('.')
+				itoa(buf, t.Nanosecond()/1e3, 6)
+			}
+			buf.WriteByte(' ')
+		}
+	}
+	if reqId != "" {
+		buf.WriteByte('[')
+		buf.WriteString(reqId)
+		buf.WriteByte(']')
+		buf.WriteByte(' ')
+	}
+
+	if l.flag&(Lshortcolor|Llongcolor) != 0 {
+		buf.WriteString(fmt.Sprintf("\033[1;%dm", colors[lvl]))
+	}
+	if l.flag&Llevel != 0 {
+		buf.WriteString(levels[lvl])
+		buf.WriteByte(' ')
+	}
+	if l.flag&Lshortcolor != 0 {
+		buf.WriteString("\033[0m")
+	}
+
+	if l.flag&Lmodule != 0 {
+		buf.WriteByte('[')
+		buf.WriteString(moduleOf(file))
+		buf.WriteByte(']')
+		buf.WriteByte(' ')
+	}
+	if l.flag&(Lshortfile|Llongfile) != 0 {
+		if l.flag&Lshortfile != 0 {
+			short := file
+			for i := len(file) - 1; i > 0; i-- {
+				if file[i] == '/' {
+					short = file[i+1:]
+					break
+				}
+			}
+			file = short
+		}
+		buf.WriteString(file)
+		buf.WriteByte(':')
+		itoa(buf, line, -1)
+		buf.WriteByte(' ')
+	}
+}
+
+// Output writes the output for a logging event.  The string s contains
+// the text to print after the prefix specified by the flags of the
+// Logger.  A newline is appended if the last character of s is not
+// already a newline.  Calldepth is used to recover the PC and is
+// provided for generality, although at the moment on all pre-defined
+// paths it will be 2.
+func (l *Logger) Output(reqId string, lvl int, calldepth int, s string) error {
+	if lvl < l.Level {
+		return nil
+	}
+	now := time.Now().In(l.loc) // get this early.
+	var file string
+	var line int
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.flag&(Lshortfile|Llongfile|Lmodule) != 0 {
+		// release lock while getting caller info - it's expensive.
+		l.mu.Unlock()
+		var ok bool
+		_, file, line, ok = runtime.Caller(calldepth)
+		if !ok {
+			file = "???"
+			line = 0
+		}
+		l.mu.Lock()
+	}
+	l.levelStats[lvl]++
+	l.buf.Reset()
+	l.formatHeader(&l.buf, now, file, line, lvl, reqId)
+	l.buf.WriteString(s)
+	if l.flag&Llongcolor != 0 {
+		l.buf.WriteString("\033[0m")
+	}
+	if len(s) > 0 && s[len(s)-1] != '\n' {
+		l.buf.WriteByte('\n')
+	}
+	_, err := l.out.Write(l.buf.Bytes())
+	return err
+}
+
+// -----------------------------------------
+
+// Printf calls l.Output to print to the logger.
+// Arguments are handled in the manner of fmt.Printf.
+func (l *Logger) Printf(format string, v ...interface{}) {
+	l.Output("", Linfo, 2, fmt.Sprintf(format, v...))
+}
+
+// Print calls l.Output to print to the logger.
+// Arguments are handled in the manner of fmt.Print.
+func (l *Logger) Print(v ...interface{}) {
+	l.Output("", Linfo, 2, fmt.Sprint(v...))
+}
+
+// Println calls l.Output to print to the logger.
+// Arguments are handled in the manner of fmt.Println.
+func (l *Logger) Println(v ...interface{}) {
+	l.Output("", Linfo, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func (l *Logger) Debugf(format string, v ...interface{}) {
+	l.Output("", Ldebug, 2, fmt.Sprintf(format, v...))
+}
+
+func (l *Logger) Debug(v ...interface{}) {
+	l.Output("", Ldebug, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+func (l *Logger) Infof(format string, v ...interface{}) {
+	l.Output("", Linfo, 2, fmt.Sprintf(format, v...))
+}
+
+func (l *Logger) Info(v ...interface{}) {
+	l.Output("", Linfo, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+func (l *Logger) Warnf(format string, v ...interface{}) {
+	l.Output("", Lwarn, 2, fmt.Sprintf(format, v...))
+}
+
+func (l *Logger) Warn(v ...interface{}) {
+	l.Output("", Lwarn, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func (l *Logger) Errorf(format string, v ...interface{}) {
+	l.Output("", Lerror, 2, fmt.Sprintf(format, v...))
+}
+
+func (l *Logger) Error(v ...interface{}) {
+	l.Output("", Lerror, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func (l *Logger) Fatal(v ...interface{}) {
+	l.Output("", Lfatal, 2, fmt.Sprintln(v...))
+	os.Exit(1)
+}
+
+// Fatalf is equivalent to l.Printf() followed by a call to os.Exit(1).
+func (l *Logger) Fatalf(format string, v ...interface{}) {
+	l.Output("", Lfatal, 2, fmt.Sprintf(format, v...))
+	os.Exit(1)
+}
+
+// -----------------------------------------
+// Panic is equivalent to l.Print() followed by a call to panic().
+func (l *Logger) Panic(v ...interface{}) {
+	s := fmt.Sprintln(v...)
+	l.Output("", Lpanic, 2, s)
+	panic(s)
+}
+
+// Panicf is equivalent to l.Printf() followed by a call to panic().
+func (l *Logger) Panicf(format string, v ...interface{}) {
+	s := fmt.Sprintf(format, v...)
+	l.Output("", Lpanic, 2, s)
+	panic(s)
+}
+
+// -----------------------------------------
+func (l *Logger) Stack(v ...interface{}) {
+	s := fmt.Sprint(v...)
+	s += "\n"
+	buf := make([]byte, 1024*1024)
+	n := runtime.Stack(buf, true)
+	s += string(buf[:n])
+	s += "\n"
+	l.Output("", Lerror, 2, s)
+}
+
+// -----------------------------------------
+func (l *Logger) Stat() (stats []int64) {
+	l.mu.Lock()
+	v := l.levelStats
+	l.mu.Unlock()
+	return v[:]
+}
+
+// Flags returns the output flags for the logger.
+func (l *Logger) Flags() int {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.flag
+}
+
+func RmColorFlags(flag int) int {
+	// for un std out, it should not show color since almost them don't support
+	if flag&Llongcolor != 0 {
+		flag = flag ^ Llongcolor
+	}
+	if flag&Lshortcolor != 0 {
+		flag = flag ^ Lshortcolor
+	}
+	return flag
+}
+
+func (l *Logger) Location() *time.Location {
+	return l.loc
+}
+
+func (l *Logger) SetLocation(loc *time.Location) {
+	l.loc = loc
+}
+
+// SetFlags sets the output flags for the logger.
+func (l *Logger) SetFlags(flag int) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	if l.out != os.Stdout {
+		flag = RmColorFlags(flag)
+	}
+	l.flag = flag
+}
+
+// Prefix returns the output prefix for the logger.
+func (l *Logger) Prefix() string {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	return l.prefix
+}
+
+// SetPrefix sets the output prefix for the logger.
+func (l *Logger) SetPrefix(prefix string) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.prefix = prefix
+}
+
+// SetOutputLevel sets the output level for the logger.
+func (l *Logger) SetOutputLevel(lvl int) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.Level = lvl
+}
+
+func (l *Logger) OutputLevel() int {
+	return l.Level
+}
+
+func (l *Logger) SetOutput(w io.Writer) {
+	l.mu.Lock()
+	defer l.mu.Unlock()
+	l.out = w
+	if w != os.Stdout {
+		l.flag = RmColorFlags(l.flag)
+	}
+}
+
+// SetOutput sets the output destination for the standard logger.
+func SetOutput(w io.Writer) {
+	Std.SetOutput(w)
+}
+
+func SetLocation(loc *time.Location) {
+	Std.SetLocation(loc)
+}
+
+func Location() *time.Location {
+	return Std.Location()
+}
+
+// Flags returns the output flags for the standard logger.
+func Flags() int {
+	return Std.Flags()
+}
+
+// SetFlags sets the output flags for the standard logger.
+func SetFlags(flag int) {
+	Std.SetFlags(flag)
+}
+
+// Prefix returns the output prefix for the standard logger.
+func Prefix() string {
+	return Std.Prefix()
+}
+
+// SetPrefix sets the output prefix for the standard logger.
+func SetPrefix(prefix string) {
+	Std.SetPrefix(prefix)
+}
+
+func SetOutputLevel(lvl int) {
+	Std.SetOutputLevel(lvl)
+}
+
+func OutputLevel() int {
+	return Std.OutputLevel()
+}
+
+// -----------------------------------------
+
+// Print calls Output to print to the standard logger.
+// Arguments are handled in the manner of fmt.Print.
+func Print(v ...interface{}) {
+	Std.Output("", Linfo, 2, fmt.Sprintln(v...))
+}
+
+// Printf calls Output to print to the standard logger.
+// Arguments are handled in the manner of fmt.Printf.
+func Printf(format string, v ...interface{}) {
+	Std.Output("", Linfo, 2, fmt.Sprintf(format, v...))
+}
+
+// Println calls Output to print to the standard logger.
+// Arguments are handled in the manner of fmt.Println.
+func Println(v ...interface{}) {
+	Std.Output("", Linfo, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func Debugf(format string, v ...interface{}) {
+	Std.Output("", Ldebug, 2, fmt.Sprintf(format, v...))
+}
+
+func Debug(v ...interface{}) {
+	Std.Output("", Ldebug, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func Infof(format string, v ...interface{}) {
+	Std.Output("", Linfo, 2, fmt.Sprintf(format, v...))
+}
+
+func Info(v ...interface{}) {
+	Std.Output("", Linfo, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func Warnf(format string, v ...interface{}) {
+	Std.Output("", Lwarn, 2, fmt.Sprintf(format, v...))
+}
+
+func Warn(v ...interface{}) {
+	Std.Output("", Lwarn, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+func Errorf(format string, v ...interface{}) {
+	Std.Output("", Lerror, 2, fmt.Sprintf(format, v...))
+}
+
+func Error(v ...interface{}) {
+	Std.Output("", Lerror, 2, fmt.Sprintln(v...))
+}
+
+// -----------------------------------------
+
+// Fatal is equivalent to Print() followed by a call to os.Exit(1).
+func Fatal(v ...interface{}) {
+	Std.Output("", Lfatal, 2, fmt.Sprintln(v...))
+}
+
+// Fatalf is equivalent to Printf() followed by a call to os.Exit(1).
+func Fatalf(format string, v ...interface{}) {
+	Std.Output("", Lfatal, 2, fmt.Sprintf(format, v...))
+}
+
+// -----------------------------------------
+
+// Panic is equivalent to Print() followed by a call to panic().
+func Panic(v ...interface{}) {
+	Std.Output("", Lpanic, 2, fmt.Sprintln(v...))
+}
+
+// Panicf is equivalent to Printf() followed by a call to panic().
+func Panicf(format string, v ...interface{}) {
+	Std.Output("", Lpanic, 2, fmt.Sprintf(format, v...))
+}
+
+// -----------------------------------------
+
+func Stack(v ...interface{}) {
+	s := fmt.Sprint(v...)
+	s += "\n"
+	buf := make([]byte, 1024*1024)
+	n := runtime.Stack(buf, true)
+	s += string(buf[:n])
+	s += "\n"
+	Std.Output("", Lerror, 2, s)
+}
+
+// -----------------------------------------
diff --git a/vendor/github.com/lunny/nodb/LICENSE b/vendor/github.com/lunny/nodb/LICENSE
new file mode 100644
index 0000000000..7ece9fdf5a
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/LICENSE
@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2014 siddontang
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
\ No newline at end of file
diff --git a/vendor/github.com/lunny/nodb/batch.go b/vendor/github.com/lunny/nodb/batch.go
new file mode 100644
index 0000000000..e69d96a122
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/batch.go
@@ -0,0 +1,106 @@
+package nodb
+
+import (
+	"sync"
+
+	"github.com/lunny/nodb/store"
+)
+
+type batch struct {
+	l *Nodb
+
+	store.WriteBatch
+
+	sync.Locker
+
+	logs [][]byte
+
+	tx *Tx
+}
+
+func (b *batch) Commit() error {
+	b.l.commitLock.Lock()
+	defer b.l.commitLock.Unlock()
+
+	err := b.WriteBatch.Commit()
+
+	if b.l.binlog != nil {
+		if err == nil {
+			if b.tx == nil {
+				b.l.binlog.Log(b.logs...)
+			} else {
+				b.tx.logs = append(b.tx.logs, b.logs...)
+			}
+		}
+		b.logs = [][]byte{}
+	}
+
+	return err
+}
+
+func (b *batch) Lock() {
+	b.Locker.Lock()
+}
+
+func (b *batch) Unlock() {
+	if b.l.binlog != nil {
+		b.logs = [][]byte{}
+	}
+	b.WriteBatch.Rollback()
+	b.Locker.Unlock()
+}
+
+func (b *batch) Put(key []byte, value []byte) {
+	if b.l.binlog != nil {
+		buf := encodeBinLogPut(key, value)
+		b.logs = append(b.logs, buf)
+	}
+	b.WriteBatch.Put(key, value)
+}
+
+func (b *batch) Delete(key []byte) {
+	if b.l.binlog != nil {
+		buf := encodeBinLogDelete(key)
+		b.logs = append(b.logs, buf)
+	}
+	b.WriteBatch.Delete(key)
+}
+
+type dbBatchLocker struct {
+	l      *sync.Mutex
+	wrLock *sync.RWMutex
+}
+
+func (l *dbBatchLocker) Lock() {
+	l.wrLock.RLock()
+	l.l.Lock()
+}
+
+func (l *dbBatchLocker) Unlock() {
+	l.l.Unlock()
+	l.wrLock.RUnlock()
+}
+
+type txBatchLocker struct {
+}
+
+func (l *txBatchLocker) Lock()   {}
+func (l *txBatchLocker) Unlock() {}
+
+type multiBatchLocker struct {
+}
+
+func (l *multiBatchLocker) Lock()   {}
+func (l *multiBatchLocker) Unlock() {}
+
+func (l *Nodb) newBatch(wb store.WriteBatch, locker sync.Locker, tx *Tx) *batch {
+	b := new(batch)
+	b.l = l
+	b.WriteBatch = wb
+
+	b.tx = tx
+	b.Locker = locker
+
+	b.logs = [][]byte{}
+	return b
+}
diff --git a/vendor/github.com/lunny/nodb/binlog.go b/vendor/github.com/lunny/nodb/binlog.go
new file mode 100644
index 0000000000..4c094d9463
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/binlog.go
@@ -0,0 +1,391 @@
+package nodb
+
+import (
+	"bufio"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/lunny/log"
+	"github.com/lunny/nodb/config"
+)
+
+type BinLogHead struct {
+	CreateTime uint32
+	BatchId    uint32
+	PayloadLen uint32
+}
+
+func (h *BinLogHead) Len() int {
+	return 12
+}
+
+func (h *BinLogHead) Write(w io.Writer) error {
+	if err := binary.Write(w, binary.BigEndian, h.CreateTime); err != nil {
+		return err
+	}
+
+	if err := binary.Write(w, binary.BigEndian, h.BatchId); err != nil {
+		return err
+	}
+
+	if err := binary.Write(w, binary.BigEndian, h.PayloadLen); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (h *BinLogHead) handleReadError(err error) error {
+	if err == io.EOF {
+		return io.ErrUnexpectedEOF
+	} else {
+		return err
+	}
+}
+
+func (h *BinLogHead) Read(r io.Reader) error {
+	var err error
+	if err = binary.Read(r, binary.BigEndian, &h.CreateTime); err != nil {
+		return err
+	}
+
+	if err = binary.Read(r, binary.BigEndian, &h.BatchId); err != nil {
+		return h.handleReadError(err)
+	}
+
+	if err = binary.Read(r, binary.BigEndian, &h.PayloadLen); err != nil {
+		return h.handleReadError(err)
+	}
+
+	return nil
+}
+
+func (h *BinLogHead) InSameBatch(ho *BinLogHead) bool {
+	if h.CreateTime == ho.CreateTime && h.BatchId == ho.BatchId {
+		return true
+	} else {
+		return false
+	}
+}
+
+/*
+index file format:
+ledis-bin.00001
+ledis-bin.00002
+ledis-bin.00003
+
+log file format
+
+Log: Head|PayloadData
+
+Head: createTime|batchId|payloadData
+
+*/
+
+type BinLog struct {
+	sync.Mutex
+
+	path string
+
+	cfg *config.BinLogConfig
+
+	logFile *os.File
+
+	logWb *bufio.Writer
+
+	indexName    string
+	logNames     []string
+	lastLogIndex int64
+
+	batchId uint32
+
+	ch chan struct{}
+}
+
+func NewBinLog(cfg *config.Config) (*BinLog, error) {
+	l := new(BinLog)
+
+	l.cfg = &cfg.BinLog
+	l.cfg.Adjust()
+
+	l.path = path.Join(cfg.DataDir, "binlog")
+
+	if err := os.MkdirAll(l.path, os.ModePerm); err != nil {
+		return nil, err
+	}
+
+	l.logNames = make([]string, 0, 16)
+
+	l.ch = make(chan struct{})
+
+	if err := l.loadIndex(); err != nil {
+		return nil, err
+	}
+
+	return l, nil
+}
+
+func (l *BinLog) flushIndex() error {
+	data := strings.Join(l.logNames, "\n")
+
+	bakName := fmt.Sprintf("%s.bak", l.indexName)
+	f, err := os.OpenFile(bakName, os.O_WRONLY|os.O_CREATE, 0666)
+	if err != nil {
+		log.Error("create binlog bak index error %s", err.Error())
+		return err
+	}
+
+	if _, err := f.WriteString(data); err != nil {
+		log.Error("write binlog index error %s", err.Error())
+		f.Close()
+		return err
+	}
+
+	f.Close()
+
+	if err := os.Rename(bakName, l.indexName); err != nil {
+		log.Error("rename binlog bak index error %s", err.Error())
+		return err
+	}
+
+	return nil
+}
+
+func (l *BinLog) loadIndex() error {
+	l.indexName = path.Join(l.path, fmt.Sprintf("ledis-bin.index"))
+	if _, err := os.Stat(l.indexName); os.IsNotExist(err) {
+		//no index file, nothing to do
+	} else {
+		indexData, err := ioutil.ReadFile(l.indexName)
+		if err != nil {
+			return err
+		}
+
+		lines := strings.Split(string(indexData), "\n")
+		for _, line := range lines {
+			line = strings.Trim(line, "\r\n ")
+			if len(line) == 0 {
+				continue
+			}
+
+			if _, err := os.Stat(path.Join(l.path, line)); err != nil {
+				log.Error("load index line %s error %s", line, err.Error())
+				return err
+			} else {
+				l.logNames = append(l.logNames, line)
+			}
+		}
+	}
+	if l.cfg.MaxFileNum > 0 && len(l.logNames) > l.cfg.MaxFileNum {
+		//remove oldest logfile
+		if err := l.Purge(len(l.logNames) - l.cfg.MaxFileNum); err != nil {
+			return err
+		}
+	}
+
+	var err error
+	if len(l.logNames) == 0 {
+		l.lastLogIndex = 1
+	} else {
+		lastName := l.logNames[len(l.logNames)-1]
+
+		if l.lastLogIndex, err = strconv.ParseInt(path.Ext(lastName)[1:], 10, 64); err != nil {
+			log.Error("invalid logfile name %s", err.Error())
+			return err
+		}
+
+		//like mysql, if server restart, a new binlog will create
+		l.lastLogIndex++
+	}
+
+	return nil
+}
+
+func (l *BinLog) getLogFile() string {
+	return l.FormatLogFileName(l.lastLogIndex)
+}
+
+func (l *BinLog) openNewLogFile() error {
+	var err error
+	lastName := l.getLogFile()
+
+	logPath := path.Join(l.path, lastName)
+	if l.logFile, err = os.OpenFile(logPath, os.O_CREATE|os.O_WRONLY, 0666); err != nil {
+		log.Error("open new logfile error %s", err.Error())
+		return err
+	}
+
+	if l.cfg.MaxFileNum > 0 && len(l.logNames) == l.cfg.MaxFileNum {
+		l.purge(1)
+	}
+
+	l.logNames = append(l.logNames, lastName)
+
+	if l.logWb == nil {
+		l.logWb = bufio.NewWriterSize(l.logFile, 1024)
+	} else {
+		l.logWb.Reset(l.logFile)
+	}
+
+	if err = l.flushIndex(); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (l *BinLog) checkLogFileSize() bool {
+	if l.logFile == nil {
+		return false
+	}
+
+	st, _ := l.logFile.Stat()
+	if st.Size() >= int64(l.cfg.MaxFileSize) {
+		l.closeLog()
+		return true
+	}
+
+	return false
+}
+
+func (l *BinLog) closeLog() {
+	l.lastLogIndex++
+
+	l.logFile.Close()
+	l.logFile = nil
+}
+
+func (l *BinLog) purge(n int) {
+	for i := 0; i < n; i++ {
+		logPath := path.Join(l.path, l.logNames[i])
+		os.Remove(logPath)
+	}
+
+	copy(l.logNames[0:], l.logNames[n:])
+	l.logNames = l.logNames[0 : len(l.logNames)-n]
+}
+
+func (l *BinLog) Close() {
+	if l.logFile != nil {
+		l.logFile.Close()
+		l.logFile = nil
+	}
+}
+
+func (l *BinLog) LogNames() []string {
+	return l.logNames
+}
+
+func (l *BinLog) LogFileName() string {
+	return l.getLogFile()
+}
+
+func (l *BinLog) LogFilePos() int64 {
+	if l.logFile == nil {
+		return 0
+	} else {
+		st, _ := l.logFile.Stat()
+		return st.Size()
+	}
+}
+
+func (l *BinLog) LogFileIndex() int64 {
+	return l.lastLogIndex
+}
+
+func (l *BinLog) FormatLogFileName(index int64) string {
+	return fmt.Sprintf("ledis-bin.%07d", index)
+}
+
+func (l *BinLog) FormatLogFilePath(index int64) string {
+	return path.Join(l.path, l.FormatLogFileName(index))
+}
+
+func (l *BinLog) LogPath() string {
+	return l.path
+}
+
+func (l *BinLog) Purge(n int) error {
+	l.Lock()
+	defer l.Unlock()
+
+	if len(l.logNames) == 0 {
+		return nil
+	}
+
+	if n >= len(l.logNames) {
+		n = len(l.logNames)
+		//can not purge current log file
+		if l.logNames[n-1] == l.getLogFile() {
+			n = n - 1
+		}
+	}
+
+	l.purge(n)
+
+	return l.flushIndex()
+}
+
+func (l *BinLog) PurgeAll() error {
+	l.Lock()
+	defer l.Unlock()
+
+	l.closeLog()
+	return l.openNewLogFile()
+}
+
+func (l *BinLog) Log(args ...[]byte) error {
+	l.Lock()
+	defer l.Unlock()
+
+	var err error
+
+	if l.logFile == nil {
+		if err = l.openNewLogFile(); err != nil {
+			return err
+		}
+	}
+
+	head := &BinLogHead{}
+
+	head.CreateTime = uint32(time.Now().Unix())
+	head.BatchId = l.batchId
+
+	l.batchId++
+
+	for _, data := range args {
+		head.PayloadLen = uint32(len(data))
+
+		if err := head.Write(l.logWb); err != nil {
+			return err
+		}
+
+		if _, err := l.logWb.Write(data); err != nil {
+			return err
+		}
+	}
+
+	if err = l.logWb.Flush(); err != nil {
+		log.Error("write log error %s", err.Error())
+		return err
+	}
+
+	l.checkLogFileSize()
+
+	close(l.ch)
+	l.ch = make(chan struct{})
+
+	return nil
+}
+
+func (l *BinLog) Wait() <-chan struct{} {
+	return l.ch
+}
diff --git a/vendor/github.com/lunny/nodb/binlog_util.go b/vendor/github.com/lunny/nodb/binlog_util.go
new file mode 100644
index 0000000000..22124dda07
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/binlog_util.go
@@ -0,0 +1,215 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"strconv"
+)
+
+var (
+	errBinLogDeleteType  = errors.New("invalid bin log delete type")
+	errBinLogPutType     = errors.New("invalid bin log put type")
+	errBinLogCommandType = errors.New("invalid bin log command type")
+)
+
+func encodeBinLogDelete(key []byte) []byte {
+	buf := make([]byte, 1+len(key))
+	buf[0] = BinLogTypeDeletion
+	copy(buf[1:], key)
+	return buf
+}
+
+func decodeBinLogDelete(sz []byte) ([]byte, error) {
+	if len(sz) < 1 || sz[0] != BinLogTypeDeletion {
+		return nil, errBinLogDeleteType
+	}
+
+	return sz[1:], nil
+}
+
+func encodeBinLogPut(key []byte, value []byte) []byte {
+	buf := make([]byte, 3+len(key)+len(value))
+	buf[0] = BinLogTypePut
+	pos := 1
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+	pos += 2
+	copy(buf[pos:], key)
+	pos += len(key)
+	copy(buf[pos:], value)
+
+	return buf
+}
+
+func decodeBinLogPut(sz []byte) ([]byte, []byte, error) {
+	if len(sz) < 3 || sz[0] != BinLogTypePut {
+		return nil, nil, errBinLogPutType
+	}
+
+	keyLen := int(binary.BigEndian.Uint16(sz[1:]))
+	if 3+keyLen > len(sz) {
+		return nil, nil, errBinLogPutType
+	}
+
+	return sz[3 : 3+keyLen], sz[3+keyLen:], nil
+}
+
+func FormatBinLogEvent(event []byte) (string, error) {
+	logType := uint8(event[0])
+
+	var err error
+	var k []byte
+	var v []byte
+
+	var buf []byte = make([]byte, 0, 1024)
+
+	switch logType {
+	case BinLogTypePut:
+		k, v, err = decodeBinLogPut(event)
+		buf = append(buf, "PUT "...)
+	case BinLogTypeDeletion:
+		k, err = decodeBinLogDelete(event)
+		buf = append(buf, "DELETE "...)
+	default:
+		err = errInvalidBinLogEvent
+	}
+
+	if err != nil {
+		return "", err
+	}
+
+	if buf, err = formatDataKey(buf, k); err != nil {
+		return "", err
+	}
+
+	if v != nil && len(v) != 0 {
+		buf = append(buf, fmt.Sprintf(" %q", v)...)
+	}
+
+	return String(buf), nil
+}
+
+func formatDataKey(buf []byte, k []byte) ([]byte, error) {
+	if len(k) < 2 {
+		return nil, errInvalidBinLogEvent
+	}
+
+	buf = append(buf, fmt.Sprintf("DB:%2d ", k[0])...)
+	buf = append(buf, fmt.Sprintf("%s ", TypeName[k[1]])...)
+
+	db := new(DB)
+	db.index = k[0]
+
+	//to do format at respective place
+
+	switch k[1] {
+	case KVType:
+		if key, err := db.decodeKVKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	case HashType:
+		if key, field, err := db.hDecodeHashKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendQuote(buf, String(field))
+		}
+	case HSizeType:
+		if key, err := db.hDecodeSizeKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	case ListType:
+		if key, seq, err := db.lDecodeListKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendInt(buf, int64(seq), 10)
+		}
+	case LMetaType:
+		if key, err := db.lDecodeMetaKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	case ZSetType:
+		if key, m, err := db.zDecodeSetKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendQuote(buf, String(m))
+		}
+	case ZSizeType:
+		if key, err := db.zDecodeSizeKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	case ZScoreType:
+		if key, m, score, err := db.zDecodeScoreKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendQuote(buf, String(m))
+			buf = append(buf, ' ')
+			buf = strconv.AppendInt(buf, score, 10)
+		}
+	case BitType:
+		if key, seq, err := db.bDecodeBinKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendUint(buf, uint64(seq), 10)
+		}
+	case BitMetaType:
+		if key, err := db.bDecodeMetaKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	case SetType:
+		if key, member, err := db.sDecodeSetKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendQuote(buf, String(member))
+		}
+	case SSizeType:
+		if key, err := db.sDecodeSizeKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	case ExpTimeType:
+		if tp, key, t, err := db.expDecodeTimeKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = append(buf, TypeName[tp]...)
+			buf = append(buf, ' ')
+			buf = strconv.AppendQuote(buf, String(key))
+			buf = append(buf, ' ')
+			buf = strconv.AppendInt(buf, t, 10)
+		}
+	case ExpMetaType:
+		if tp, key, err := db.expDecodeMetaKey(k); err != nil {
+			return nil, err
+		} else {
+			buf = append(buf, TypeName[tp]...)
+			buf = append(buf, ' ')
+			buf = strconv.AppendQuote(buf, String(key))
+		}
+	default:
+		return nil, errInvalidBinLogEvent
+	}
+
+	return buf, nil
+}
diff --git a/vendor/github.com/lunny/nodb/config/config.go b/vendor/github.com/lunny/nodb/config/config.go
new file mode 100644
index 0000000000..3b44d3043f
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/config/config.go
@@ -0,0 +1,135 @@
+package config
+
+import (
+	"io/ioutil"
+
+	"github.com/BurntSushi/toml"
+)
+
+type Size int
+
+const (
+	DefaultAddr     string = "127.0.0.1:6380"
+	DefaultHttpAddr string = "127.0.0.1:11181"
+
+	DefaultDBName string = "goleveldb"
+
+	DefaultDataDir string = "./data"
+)
+
+const (
+	MaxBinLogFileSize int = 1024 * 1024 * 1024
+	MaxBinLogFileNum  int = 10000
+
+	DefaultBinLogFileSize int = MaxBinLogFileSize
+	DefaultBinLogFileNum  int = 10
+)
+
+type LevelDBConfig struct {
+	Compression     bool `toml:"compression"`
+	BlockSize       int  `toml:"block_size"`
+	WriteBufferSize int  `toml:"write_buffer_size"`
+	CacheSize       int  `toml:"cache_size"`
+	MaxOpenFiles    int  `toml:"max_open_files"`
+}
+
+type LMDBConfig struct {
+	MapSize int  `toml:"map_size"`
+	NoSync  bool `toml:"nosync"`
+}
+
+type BinLogConfig struct {
+	MaxFileSize int `toml:"max_file_size"`
+	MaxFileNum  int `toml:"max_file_num"`
+}
+
+type Config struct {
+	DataDir string `toml:"data_dir"`
+
+	DBName string `toml:"db_name"`
+
+	LevelDB LevelDBConfig `toml:"leveldb"`
+
+	LMDB LMDBConfig `toml:"lmdb"`
+
+	BinLog BinLogConfig `toml:"binlog"`
+
+	SlaveOf string `toml:"slaveof"`
+
+	AccessLog string `toml:"access_log"`
+}
+
+func NewConfigWithFile(fileName string) (*Config, error) {
+	data, err := ioutil.ReadFile(fileName)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewConfigWithData(data)
+}
+
+func NewConfigWithData(data []byte) (*Config, error) {
+	cfg := NewConfigDefault()
+
+	_, err := toml.Decode(string(data), cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	return cfg, nil
+}
+
+func NewConfigDefault() *Config {
+	cfg := new(Config)
+
+	cfg.DataDir = DefaultDataDir
+
+	cfg.DBName = DefaultDBName
+
+	// disable binlog
+	cfg.BinLog.MaxFileNum = 0
+	cfg.BinLog.MaxFileSize = 0
+
+	// disable replication
+	cfg.SlaveOf = ""
+
+	// disable access log
+	cfg.AccessLog = ""
+
+	cfg.LMDB.MapSize = 20 * 1024 * 1024
+	cfg.LMDB.NoSync = true
+
+	return cfg
+}
+
+func (cfg *LevelDBConfig) Adjust() {
+	if cfg.CacheSize <= 0 {
+		cfg.CacheSize = 4 * 1024 * 1024
+	}
+
+	if cfg.BlockSize <= 0 {
+		cfg.BlockSize = 4 * 1024
+	}
+
+	if cfg.WriteBufferSize <= 0 {
+		cfg.WriteBufferSize = 4 * 1024 * 1024
+	}
+
+	if cfg.MaxOpenFiles < 1024 {
+		cfg.MaxOpenFiles = 1024
+	}
+}
+
+func (cfg *BinLogConfig) Adjust() {
+	if cfg.MaxFileSize <= 0 {
+		cfg.MaxFileSize = DefaultBinLogFileSize
+	} else if cfg.MaxFileSize > MaxBinLogFileSize {
+		cfg.MaxFileSize = MaxBinLogFileSize
+	}
+
+	if cfg.MaxFileNum <= 0 {
+		cfg.MaxFileNum = DefaultBinLogFileNum
+	} else if cfg.MaxFileNum > MaxBinLogFileNum {
+		cfg.MaxFileNum = MaxBinLogFileNum
+	}
+}
diff --git a/vendor/github.com/lunny/nodb/const.go b/vendor/github.com/lunny/nodb/const.go
new file mode 100644
index 0000000000..446dae634e
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/const.go
@@ -0,0 +1,98 @@
+package nodb
+
+import (
+	"errors"
+)
+
+const (
+	NoneType    byte = 0
+	KVType      byte = 1
+	HashType    byte = 2
+	HSizeType   byte = 3
+	ListType    byte = 4
+	LMetaType   byte = 5
+	ZSetType    byte = 6
+	ZSizeType   byte = 7
+	ZScoreType  byte = 8
+	BitType     byte = 9
+	BitMetaType byte = 10
+	SetType     byte = 11
+	SSizeType   byte = 12
+
+	maxDataType byte = 100
+
+	ExpTimeType byte = 101
+	ExpMetaType byte = 102
+)
+
+var (
+	TypeName = map[byte]string{
+		KVType:      "kv",
+		HashType:    "hash",
+		HSizeType:   "hsize",
+		ListType:    "list",
+		LMetaType:   "lmeta",
+		ZSetType:    "zset",
+		ZSizeType:   "zsize",
+		ZScoreType:  "zscore",
+		BitType:     "bit",
+		BitMetaType: "bitmeta",
+		SetType:     "set",
+		SSizeType:   "ssize",
+		ExpTimeType: "exptime",
+		ExpMetaType: "expmeta",
+	}
+)
+
+const (
+	defaultScanCount int = 10
+)
+
+var (
+	errKeySize        = errors.New("invalid key size")
+	errValueSize      = errors.New("invalid value size")
+	errHashFieldSize  = errors.New("invalid hash field size")
+	errSetMemberSize  = errors.New("invalid set member size")
+	errZSetMemberSize = errors.New("invalid zset member size")
+	errExpireValue    = errors.New("invalid expire value")
+)
+
+const (
+	//we don't support too many databases
+	MaxDBNumber uint8 = 16
+
+	//max key size
+	MaxKeySize int = 1024
+
+	//max hash field size
+	MaxHashFieldSize int = 1024
+
+	//max zset member size
+	MaxZSetMemberSize int = 1024
+
+	//max set member size
+	MaxSetMemberSize int = 1024
+
+	//max value size
+	MaxValueSize int = 10 * 1024 * 1024
+)
+
+var (
+	ErrScoreMiss = errors.New("zset score miss")
+)
+
+const (
+	BinLogTypeDeletion uint8 = 0x0
+	BinLogTypePut      uint8 = 0x1
+	BinLogTypeCommand  uint8 = 0x2
+)
+
+const (
+	DBAutoCommit    uint8 = 0x0
+	DBInTransaction uint8 = 0x1
+	DBInMulti       uint8 = 0x2
+)
+
+var (
+	Version = "0.1"
+)
diff --git a/vendor/github.com/lunny/nodb/doc.go b/vendor/github.com/lunny/nodb/doc.go
new file mode 100644
index 0000000000..2f7df33ffd
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/doc.go
@@ -0,0 +1,61 @@
+// package nodb is a high performance embedded NoSQL.
+//
+// nodb supports various data structure like kv, list, hash and zset like redis.
+//
+// Other features include binlog replication, data with a limited time-to-live.
+//
+// Usage
+//
+// First create a nodb instance before use:
+//
+//  l := nodb.Open(cfg)
+//
+// cfg is a Config instance which contains configuration for nodb use,
+// like DataDir (root directory for nodb working to store data).
+//
+// After you create a nodb instance, you can select a DB to store you data:
+//
+//  db, _ := l.Select(0)
+//
+// DB must be selected by a index, nodb supports only 16 databases, so the index range is [0-15].
+//
+// KV
+//
+// KV is the most basic nodb type like any other key-value database.
+//
+//  err := db.Set(key, value)
+//  value, err := db.Get(key)
+//
+// List
+//
+// List is simply lists of values, sorted by insertion order.
+// You can push or pop value on the list head (left) or tail (right).
+//
+//  err := db.LPush(key, value1)
+//  err := db.RPush(key, value2)
+//  value1, err := db.LPop(key)
+//  value2, err := db.RPop(key)
+//
+// Hash
+//
+// Hash is a map between fields and values.
+//
+//  n, err := db.HSet(key, field1, value1)
+//  n, err := db.HSet(key, field2, value2)
+//  value1, err := db.HGet(key, field1)
+//  value2, err := db.HGet(key, field2)
+//
+// ZSet
+//
+// ZSet is a sorted collections of values.
+// Every member of zset is associated with score, a int64 value which used to sort, from smallest to greatest score.
+// Members are unique, but score may be same.
+//
+//  n, err := db.ZAdd(key, ScorePair{score1, member1}, ScorePair{score2, member2})
+//  ay, err := db.ZRangeByScore(key, minScore, maxScore, 0, -1)
+//
+// Binlog
+//
+// nodb supports binlog, so you can sync binlog to another server for replication. If you want to open binlog support, set UseBinLog to true in config.
+//
+package nodb
diff --git a/vendor/github.com/lunny/nodb/dump.go b/vendor/github.com/lunny/nodb/dump.go
new file mode 100644
index 0000000000..3c9722e00d
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/dump.go
@@ -0,0 +1,200 @@
+package nodb
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"io"
+	"os"
+
+	"github.com/siddontang/go-snappy/snappy"
+)
+
+//dump format
+// fileIndex(bigendian int64)|filePos(bigendian int64)
+// |keylen(bigendian int32)|key|valuelen(bigendian int32)|value......
+//
+//key and value are both compressed for fast transfer dump on network using snappy
+
+type BinLogAnchor struct {
+	LogFileIndex int64
+	LogPos       int64
+}
+
+func (m *BinLogAnchor) WriteTo(w io.Writer) error {
+	if err := binary.Write(w, binary.BigEndian, m.LogFileIndex); err != nil {
+		return err
+	}
+
+	if err := binary.Write(w, binary.BigEndian, m.LogPos); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (m *BinLogAnchor) ReadFrom(r io.Reader) error {
+	err := binary.Read(r, binary.BigEndian, &m.LogFileIndex)
+	if err != nil {
+		return err
+	}
+
+	err = binary.Read(r, binary.BigEndian, &m.LogPos)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (l *Nodb) DumpFile(path string) error {
+	f, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	return l.Dump(f)
+}
+
+func (l *Nodb) Dump(w io.Writer) error {
+	m := new(BinLogAnchor)
+
+	var err error
+
+	l.wLock.Lock()
+	defer l.wLock.Unlock()
+
+	if l.binlog != nil {
+		m.LogFileIndex = l.binlog.LogFileIndex()
+		m.LogPos = l.binlog.LogFilePos()
+	}
+
+	wb := bufio.NewWriterSize(w, 4096)
+	if err = m.WriteTo(wb); err != nil {
+		return err
+	}
+
+	it := l.ldb.NewIterator()
+	it.SeekToFirst()
+
+	compressBuf := make([]byte, 4096)
+
+	var key []byte
+	var value []byte
+	for ; it.Valid(); it.Next() {
+		key = it.RawKey()
+		value = it.RawValue()
+
+		if key, err = snappy.Encode(compressBuf, key); err != nil {
+			return err
+		}
+
+		if err = binary.Write(wb, binary.BigEndian, uint16(len(key))); err != nil {
+			return err
+		}
+
+		if _, err = wb.Write(key); err != nil {
+			return err
+		}
+
+		if value, err = snappy.Encode(compressBuf, value); err != nil {
+			return err
+		}
+
+		if err = binary.Write(wb, binary.BigEndian, uint32(len(value))); err != nil {
+			return err
+		}
+
+		if _, err = wb.Write(value); err != nil {
+			return err
+		}
+	}
+
+	if err = wb.Flush(); err != nil {
+		return err
+	}
+
+	compressBuf = nil
+
+	return nil
+}
+
+func (l *Nodb) LoadDumpFile(path string) (*BinLogAnchor, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return l.LoadDump(f)
+}
+
+func (l *Nodb) LoadDump(r io.Reader) (*BinLogAnchor, error) {
+	l.wLock.Lock()
+	defer l.wLock.Unlock()
+
+	info := new(BinLogAnchor)
+
+	rb := bufio.NewReaderSize(r, 4096)
+
+	err := info.ReadFrom(rb)
+	if err != nil {
+		return nil, err
+	}
+
+	var keyLen uint16
+	var valueLen uint32
+
+	var keyBuf bytes.Buffer
+	var valueBuf bytes.Buffer
+
+	deKeyBuf := make([]byte, 4096)
+	deValueBuf := make([]byte, 4096)
+
+	var key, value []byte
+
+	for {
+		if err = binary.Read(rb, binary.BigEndian, &keyLen); err != nil && err != io.EOF {
+			return nil, err
+		} else if err == io.EOF {
+			break
+		}
+
+		if _, err = io.CopyN(&keyBuf, rb, int64(keyLen)); err != nil {
+			return nil, err
+		}
+
+		if key, err = snappy.Decode(deKeyBuf, keyBuf.Bytes()); err != nil {
+			return nil, err
+		}
+
+		if err = binary.Read(rb, binary.BigEndian, &valueLen); err != nil {
+			return nil, err
+		}
+
+		if _, err = io.CopyN(&valueBuf, rb, int64(valueLen)); err != nil {
+			return nil, err
+		}
+
+		if value, err = snappy.Decode(deValueBuf, valueBuf.Bytes()); err != nil {
+			return nil, err
+		}
+
+		if err = l.ldb.Put(key, value); err != nil {
+			return nil, err
+		}
+
+		keyBuf.Reset()
+		valueBuf.Reset()
+	}
+
+	deKeyBuf = nil
+	deValueBuf = nil
+
+	//if binlog enable, we will delete all binlogs and open a new one for handling simply
+	if l.binlog != nil {
+		l.binlog.PurgeAll()
+	}
+
+	return info, nil
+}
diff --git a/vendor/github.com/lunny/nodb/info.go b/vendor/github.com/lunny/nodb/info.go
new file mode 100644
index 0000000000..3fd37e3d44
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/info.go
@@ -0,0 +1,24 @@
+package nodb
+
+// todo, add info
+
+// type Keyspace struct {
+// 	Kvs       int `json:"kvs"`
+// 	KvExpires int `json:"kv_expires"`
+
+// 	Lists       int `json:"lists"`
+// 	ListExpires int `json:"list_expires"`
+
+// 	Bitmaps       int `json:"bitmaps"`
+// 	BitmapExpires int `json:"bitmap_expires"`
+
+// 	ZSets       int `json:"zsets"`
+// 	ZSetExpires int `json:"zset_expires"`
+
+// 	Hashes      int `json:"hashes"`
+// 	HashExpires int `json:"hahsh_expires"`
+// }
+
+// type Info struct {
+// 	KeySpaces [MaxDBNumber]Keyspace
+// }
diff --git a/vendor/github.com/lunny/nodb/multi.go b/vendor/github.com/lunny/nodb/multi.go
new file mode 100644
index 0000000000..ca581ce9a2
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/multi.go
@@ -0,0 +1,73 @@
+package nodb
+
+import (
+	"errors"
+	"fmt"
+)
+
+var (
+	ErrNestMulti = errors.New("nest multi not supported")
+	ErrMultiDone = errors.New("multi has been closed")
+)
+
+type Multi struct {
+	*DB
+}
+
+func (db *DB) IsInMulti() bool {
+	return db.status == DBInMulti
+}
+
+// begin a mutli to execute commands,
+// it will block any other write operations before you close the multi, unlike transaction, mutli can not rollback
+func (db *DB) Multi() (*Multi, error) {
+	if db.IsInMulti() {
+		return nil, ErrNestMulti
+	}
+
+	m := new(Multi)
+
+	m.DB = new(DB)
+	m.DB.status = DBInMulti
+
+	m.DB.l = db.l
+
+	m.l.wLock.Lock()
+
+	m.DB.sdb = db.sdb
+
+	m.DB.bucket = db.sdb
+
+	m.DB.index = db.index
+
+	m.DB.kvBatch = m.newBatch()
+	m.DB.listBatch = m.newBatch()
+	m.DB.hashBatch = m.newBatch()
+	m.DB.zsetBatch = m.newBatch()
+	m.DB.binBatch = m.newBatch()
+	m.DB.setBatch = m.newBatch()
+
+	return m, nil
+}
+
+func (m *Multi) newBatch() *batch {
+	return m.l.newBatch(m.bucket.NewWriteBatch(), &multiBatchLocker{}, nil)
+}
+
+func (m *Multi) Close() error {
+	if m.bucket == nil {
+		return ErrMultiDone
+	}
+	m.l.wLock.Unlock()
+	m.bucket = nil
+	return nil
+}
+
+func (m *Multi) Select(index int) error {
+	if index < 0 || index >= int(MaxDBNumber) {
+		return fmt.Errorf("invalid db index %d", index)
+	}
+
+	m.DB.index = uint8(index)
+	return nil
+}
diff --git a/vendor/github.com/lunny/nodb/nodb.go b/vendor/github.com/lunny/nodb/nodb.go
new file mode 100644
index 0000000000..fdd0272c94
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/nodb.go
@@ -0,0 +1,128 @@
+package nodb
+
+import (
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/lunny/log"
+	"github.com/lunny/nodb/config"
+	"github.com/lunny/nodb/store"
+)
+
+type Nodb struct {
+	cfg *config.Config
+
+	ldb *store.DB
+	dbs [MaxDBNumber]*DB
+
+	quit chan struct{}
+	jobs *sync.WaitGroup
+
+	binlog *BinLog
+
+	wLock      sync.RWMutex //allow one write at same time
+	commitLock sync.Mutex   //allow one write commit at same time
+}
+
+func Open(cfg *config.Config) (*Nodb, error) {
+	if len(cfg.DataDir) == 0 {
+		cfg.DataDir = config.DefaultDataDir
+	}
+
+	ldb, err := store.Open(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	l := new(Nodb)
+
+	l.quit = make(chan struct{})
+	l.jobs = new(sync.WaitGroup)
+
+	l.ldb = ldb
+
+	if cfg.BinLog.MaxFileNum > 0 && cfg.BinLog.MaxFileSize > 0 {
+		l.binlog, err = NewBinLog(cfg)
+		if err != nil {
+			return nil, err
+		}
+	} else {
+		l.binlog = nil
+	}
+
+	for i := uint8(0); i < MaxDBNumber; i++ {
+		l.dbs[i] = l.newDB(i)
+	}
+
+	l.activeExpireCycle()
+
+	return l, nil
+}
+
+func (l *Nodb) Close() {
+	close(l.quit)
+	l.jobs.Wait()
+
+	l.ldb.Close()
+
+	if l.binlog != nil {
+		l.binlog.Close()
+		l.binlog = nil
+	}
+}
+
+func (l *Nodb) Select(index int) (*DB, error) {
+	if index < 0 || index >= int(MaxDBNumber) {
+		return nil, fmt.Errorf("invalid db index %d", index)
+	}
+
+	return l.dbs[index], nil
+}
+
+func (l *Nodb) FlushAll() error {
+	for index, db := range l.dbs {
+		if _, err := db.FlushAll(); err != nil {
+			log.Error("flush db %d error %s", index, err.Error())
+		}
+	}
+
+	return nil
+}
+
+// very dangerous to use
+func (l *Nodb) DataDB() *store.DB {
+	return l.ldb
+}
+
+func (l *Nodb) activeExpireCycle() {
+	var executors []*elimination = make([]*elimination, len(l.dbs))
+	for i, db := range l.dbs {
+		executors[i] = db.newEliminator()
+	}
+
+	l.jobs.Add(1)
+	go func() {
+		tick := time.NewTicker(1 * time.Second)
+		end := false
+		done := make(chan struct{})
+		for !end {
+			select {
+			case <-tick.C:
+				go func() {
+					for _, eli := range executors {
+						eli.active()
+					}
+					done <- struct{}{}
+				}()
+				<-done
+			case <-l.quit:
+				end = true
+				break
+			}
+		}
+
+		tick.Stop()
+		l.jobs.Done()
+	}()
+}
diff --git a/vendor/github.com/lunny/nodb/nodb_db.go b/vendor/github.com/lunny/nodb/nodb_db.go
new file mode 100644
index 0000000000..f68ebaa0d4
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/nodb_db.go
@@ -0,0 +1,171 @@
+package nodb
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/lunny/nodb/store"
+)
+
+type ibucket interface {
+	Get(key []byte) ([]byte, error)
+
+	Put(key []byte, value []byte) error
+	Delete(key []byte) error
+
+	NewIterator() *store.Iterator
+
+	NewWriteBatch() store.WriteBatch
+
+	RangeIterator(min []byte, max []byte, rangeType uint8) *store.RangeLimitIterator
+	RevRangeIterator(min []byte, max []byte, rangeType uint8) *store.RangeLimitIterator
+	RangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *store.RangeLimitIterator
+	RevRangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *store.RangeLimitIterator
+}
+
+type DB struct {
+	l *Nodb
+
+	sdb *store.DB
+
+	bucket ibucket
+
+	index uint8
+
+	kvBatch   *batch
+	listBatch *batch
+	hashBatch *batch
+	zsetBatch *batch
+	binBatch  *batch
+	setBatch  *batch
+
+	status uint8
+}
+
+func (l *Nodb) newDB(index uint8) *DB {
+	d := new(DB)
+
+	d.l = l
+
+	d.sdb = l.ldb
+
+	d.bucket = d.sdb
+
+	d.status = DBAutoCommit
+	d.index = index
+
+	d.kvBatch = d.newBatch()
+	d.listBatch = d.newBatch()
+	d.hashBatch = d.newBatch()
+	d.zsetBatch = d.newBatch()
+	d.binBatch = d.newBatch()
+	d.setBatch = d.newBatch()
+
+	return d
+}
+
+func (db *DB) newBatch() *batch {
+	return db.l.newBatch(db.bucket.NewWriteBatch(), &dbBatchLocker{l: &sync.Mutex{}, wrLock: &db.l.wLock}, nil)
+}
+
+func (db *DB) Index() int {
+	return int(db.index)
+}
+
+func (db *DB) IsAutoCommit() bool {
+	return db.status == DBAutoCommit
+}
+
+func (db *DB) FlushAll() (drop int64, err error) {
+	all := [...](func() (int64, error)){
+		db.flush,
+		db.lFlush,
+		db.hFlush,
+		db.zFlush,
+		db.bFlush,
+		db.sFlush}
+
+	for _, flush := range all {
+		if n, e := flush(); e != nil {
+			err = e
+			return
+		} else {
+			drop += n
+		}
+	}
+
+	return
+}
+
+func (db *DB) newEliminator() *elimination {
+	eliminator := newEliminator(db)
+
+	eliminator.regRetireContext(KVType, db.kvBatch, db.delete)
+	eliminator.regRetireContext(ListType, db.listBatch, db.lDelete)
+	eliminator.regRetireContext(HashType, db.hashBatch, db.hDelete)
+	eliminator.regRetireContext(ZSetType, db.zsetBatch, db.zDelete)
+	eliminator.regRetireContext(BitType, db.binBatch, db.bDelete)
+	eliminator.regRetireContext(SetType, db.setBatch, db.sDelete)
+
+	return eliminator
+}
+
+func (db *DB) flushRegion(t *batch, minKey []byte, maxKey []byte) (drop int64, err error) {
+	it := db.bucket.RangeIterator(minKey, maxKey, store.RangeROpen)
+	for ; it.Valid(); it.Next() {
+		t.Delete(it.RawKey())
+		drop++
+		if drop&1023 == 0 {
+			if err = t.Commit(); err != nil {
+				return
+			}
+		}
+	}
+	it.Close()
+	return
+}
+
+func (db *DB) flushType(t *batch, dataType byte) (drop int64, err error) {
+	var deleteFunc func(t *batch, key []byte) int64
+	var metaDataType byte
+	switch dataType {
+	case KVType:
+		deleteFunc = db.delete
+		metaDataType = KVType
+	case ListType:
+		deleteFunc = db.lDelete
+		metaDataType = LMetaType
+	case HashType:
+		deleteFunc = db.hDelete
+		metaDataType = HSizeType
+	case ZSetType:
+		deleteFunc = db.zDelete
+		metaDataType = ZSizeType
+	case BitType:
+		deleteFunc = db.bDelete
+		metaDataType = BitMetaType
+	case SetType:
+		deleteFunc = db.sDelete
+		metaDataType = SSizeType
+	default:
+		return 0, fmt.Errorf("invalid data type: %s", TypeName[dataType])
+	}
+
+	var keys [][]byte
+	keys, err = db.scan(metaDataType, nil, 1024, false, "")
+	for len(keys) != 0 || err != nil {
+		for _, key := range keys {
+			deleteFunc(t, key)
+			db.rmExpire(t, dataType, key)
+
+		}
+
+		if err = t.Commit(); err != nil {
+			return
+		} else {
+			drop += int64(len(keys))
+		}
+		keys, err = db.scan(metaDataType, nil, 1024, false, "")
+	}
+	return
+}
diff --git a/vendor/github.com/lunny/nodb/replication.go b/vendor/github.com/lunny/nodb/replication.go
new file mode 100644
index 0000000000..f9bc951085
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/replication.go
@@ -0,0 +1,312 @@
+package nodb
+
+import (
+	"bufio"
+	"bytes"
+	"errors"
+	"io"
+	"os"
+	"time"
+
+	"github.com/lunny/log"
+	"github.com/lunny/nodb/store/driver"
+)
+
+const (
+	maxReplBatchNum = 100
+	maxReplLogSize  = 1 * 1024 * 1024
+)
+
+var (
+	ErrSkipEvent = errors.New("skip to next event")
+)
+
+var (
+	errInvalidBinLogEvent = errors.New("invalid binglog event")
+	errInvalidBinLogFile  = errors.New("invalid binlog file")
+)
+
+type replBatch struct {
+	wb     driver.IWriteBatch
+	events [][]byte
+	l      *Nodb
+
+	lastHead *BinLogHead
+}
+
+func (b *replBatch) Commit() error {
+	b.l.commitLock.Lock()
+	defer b.l.commitLock.Unlock()
+
+	err := b.wb.Commit()
+	if err != nil {
+		b.Rollback()
+		return err
+	}
+
+	if b.l.binlog != nil {
+		if err = b.l.binlog.Log(b.events...); err != nil {
+			b.Rollback()
+			return err
+		}
+	}
+
+	b.events = [][]byte{}
+	b.lastHead = nil
+
+	return nil
+}
+
+func (b *replBatch) Rollback() error {
+	b.wb.Rollback()
+	b.events = [][]byte{}
+	b.lastHead = nil
+	return nil
+}
+
+func (l *Nodb) replicateEvent(b *replBatch, event []byte) error {
+	if len(event) == 0 {
+		return errInvalidBinLogEvent
+	}
+
+	b.events = append(b.events, event)
+
+	logType := uint8(event[0])
+	switch logType {
+	case BinLogTypePut:
+		return l.replicatePutEvent(b, event)
+	case BinLogTypeDeletion:
+		return l.replicateDeleteEvent(b, event)
+	default:
+		return errInvalidBinLogEvent
+	}
+}
+
+func (l *Nodb) replicatePutEvent(b *replBatch, event []byte) error {
+	key, value, err := decodeBinLogPut(event)
+	if err != nil {
+		return err
+	}
+
+	b.wb.Put(key, value)
+
+	return nil
+}
+
+func (l *Nodb) replicateDeleteEvent(b *replBatch, event []byte) error {
+	key, err := decodeBinLogDelete(event)
+	if err != nil {
+		return err
+	}
+
+	b.wb.Delete(key)
+
+	return nil
+}
+
+func ReadEventFromReader(rb io.Reader, f func(head *BinLogHead, event []byte) error) error {
+	head := &BinLogHead{}
+	var err error
+
+	for {
+		if err = head.Read(rb); err != nil {
+			if err == io.EOF {
+				break
+			} else {
+				return err
+			}
+		}
+
+		var dataBuf bytes.Buffer
+
+		if _, err = io.CopyN(&dataBuf, rb, int64(head.PayloadLen)); err != nil {
+			return err
+		}
+
+		err = f(head, dataBuf.Bytes())
+		if err != nil && err != ErrSkipEvent {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (l *Nodb) ReplicateFromReader(rb io.Reader) error {
+	b := new(replBatch)
+
+	b.wb = l.ldb.NewWriteBatch()
+	b.l = l
+
+	f := func(head *BinLogHead, event []byte) error {
+		if b.lastHead == nil {
+			b.lastHead = head
+		} else if !b.lastHead.InSameBatch(head) {
+			if err := b.Commit(); err != nil {
+				log.Fatal("replication error %s, skip to next", err.Error())
+				return ErrSkipEvent
+			}
+			b.lastHead = head
+		}
+
+		err := l.replicateEvent(b, event)
+		if err != nil {
+			log.Fatal("replication error %s, skip to next", err.Error())
+			return ErrSkipEvent
+		}
+		return nil
+	}
+
+	err := ReadEventFromReader(rb, f)
+	if err != nil {
+		b.Rollback()
+		return err
+	}
+	return b.Commit()
+}
+
+func (l *Nodb) ReplicateFromData(data []byte) error {
+	rb := bytes.NewReader(data)
+
+	err := l.ReplicateFromReader(rb)
+
+	return err
+}
+
+func (l *Nodb) ReplicateFromBinLog(filePath string) error {
+	f, err := os.Open(filePath)
+	if err != nil {
+		return err
+	}
+
+	rb := bufio.NewReaderSize(f, 4096)
+
+	err = l.ReplicateFromReader(rb)
+
+	f.Close()
+
+	return err
+}
+
+// try to read events, if no events read, try to wait the new event singal until timeout seconds
+func (l *Nodb) ReadEventsToTimeout(info *BinLogAnchor, w io.Writer, timeout int) (n int, err error) {
+	lastIndex := info.LogFileIndex
+	lastPos := info.LogPos
+
+	n = 0
+	if l.binlog == nil {
+		//binlog not supported
+		info.LogFileIndex = 0
+		info.LogPos = 0
+		return
+	}
+
+	n, err = l.ReadEventsTo(info, w)
+	if err == nil && info.LogFileIndex == lastIndex && info.LogPos == lastPos {
+		//no events read
+		select {
+		case <-l.binlog.Wait():
+		case <-time.After(time.Duration(timeout) * time.Second):
+		}
+		return l.ReadEventsTo(info, w)
+	}
+	return
+}
+
+func (l *Nodb) ReadEventsTo(info *BinLogAnchor, w io.Writer) (n int, err error) {
+	n = 0
+	if l.binlog == nil {
+		//binlog not supported
+		info.LogFileIndex = 0
+		info.LogPos = 0
+		return
+	}
+
+	index := info.LogFileIndex
+	offset := info.LogPos
+
+	filePath := l.binlog.FormatLogFilePath(index)
+
+	var f *os.File
+	f, err = os.Open(filePath)
+	if os.IsNotExist(err) {
+		lastIndex := l.binlog.LogFileIndex()
+
+		if index == lastIndex {
+			//no binlog at all
+			info.LogPos = 0
+		} else {
+			//slave binlog info had lost
+			info.LogFileIndex = -1
+		}
+	}
+
+	if err != nil {
+		if os.IsNotExist(err) {
+			err = nil
+		}
+		return
+	}
+
+	defer f.Close()
+
+	var fileSize int64
+	st, _ := f.Stat()
+	fileSize = st.Size()
+
+	if fileSize == info.LogPos {
+		return
+	}
+
+	if _, err = f.Seek(offset, os.SEEK_SET); err != nil {
+		//may be invliad seek offset
+		return
+	}
+
+	var lastHead *BinLogHead = nil
+
+	head := &BinLogHead{}
+
+	batchNum := 0
+
+	for {
+		if err = head.Read(f); err != nil {
+			if err == io.EOF {
+				//we will try to use next binlog
+				if index < l.binlog.LogFileIndex() {
+					info.LogFileIndex += 1
+					info.LogPos = 0
+				}
+				err = nil
+				return
+			} else {
+				return
+			}
+
+		}
+
+		if lastHead == nil {
+			lastHead = head
+			batchNum++
+		} else if !lastHead.InSameBatch(head) {
+			lastHead = head
+			batchNum++
+			if batchNum > maxReplBatchNum || n > maxReplLogSize {
+				return
+			}
+		}
+
+		if err = head.Write(w); err != nil {
+			return
+		}
+
+		if _, err = io.CopyN(w, f, int64(head.PayloadLen)); err != nil {
+			return
+		}
+
+		n += (head.Len() + int(head.PayloadLen))
+		info.LogPos = info.LogPos + int64(head.Len()) + int64(head.PayloadLen)
+	}
+
+	return
+}
diff --git a/vendor/github.com/lunny/nodb/scan.go b/vendor/github.com/lunny/nodb/scan.go
new file mode 100644
index 0000000000..e989db3fed
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/scan.go
@@ -0,0 +1,144 @@
+package nodb
+
+import (
+	"bytes"
+	"errors"
+	"regexp"
+
+	"github.com/lunny/nodb/store"
+)
+
+var errDataType = errors.New("error data type")
+var errMetaKey = errors.New("error meta key")
+
+// Seek search the prefix key
+func (db *DB) Seek(key []byte) (*store.Iterator, error) {
+	return db.seek(KVType, key)
+}
+
+func (db *DB) seek(dataType byte, key []byte) (*store.Iterator, error) {
+	var minKey []byte
+	var err error
+
+	if len(key) > 0 {
+		if err = checkKeySize(key); err != nil {
+			return nil, err
+		}
+		if minKey, err = db.encodeMetaKey(dataType, key); err != nil {
+			return nil, err
+		}
+
+	} else {
+		if minKey, err = db.encodeMinKey(dataType); err != nil {
+			return nil, err
+		}
+	}
+
+	it := db.bucket.NewIterator()
+	it.Seek(minKey)
+	return it, nil
+}
+
+func (db *DB) MaxKey() ([]byte, error) {
+	return db.encodeMaxKey(KVType)
+}
+
+func (db *DB) Key(it *store.Iterator) ([]byte, error) {
+	return db.decodeMetaKey(KVType, it.Key())
+}
+
+func (db *DB) scan(dataType byte, key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	var minKey, maxKey []byte
+	var err error
+	var r *regexp.Regexp
+
+	if len(match) > 0 {
+		if r, err = regexp.Compile(match); err != nil {
+			return nil, err
+		}
+	}
+
+	if len(key) > 0 {
+		if err = checkKeySize(key); err != nil {
+			return nil, err
+		}
+		if minKey, err = db.encodeMetaKey(dataType, key); err != nil {
+			return nil, err
+		}
+
+	} else {
+		if minKey, err = db.encodeMinKey(dataType); err != nil {
+			return nil, err
+		}
+	}
+
+	if maxKey, err = db.encodeMaxKey(dataType); err != nil {
+		return nil, err
+	}
+
+	if count <= 0 {
+		count = defaultScanCount
+	}
+
+	v := make([][]byte, 0, count)
+
+	it := db.bucket.NewIterator()
+	it.Seek(minKey)
+
+	if !inclusive {
+		if it.Valid() && bytes.Equal(it.RawKey(), minKey) {
+			it.Next()
+		}
+	}
+
+	for i := 0; it.Valid() && i < count && bytes.Compare(it.RawKey(), maxKey) < 0; it.Next() {
+		if k, err := db.decodeMetaKey(dataType, it.Key()); err != nil {
+			continue
+		} else if r != nil && !r.Match(k) {
+			continue
+		} else {
+			v = append(v, k)
+			i++
+		}
+	}
+	it.Close()
+	return v, nil
+}
+
+func (db *DB) encodeMinKey(dataType byte) ([]byte, error) {
+	return db.encodeMetaKey(dataType, nil)
+}
+
+func (db *DB) encodeMaxKey(dataType byte) ([]byte, error) {
+	k, err := db.encodeMetaKey(dataType, nil)
+	if err != nil {
+		return nil, err
+	}
+	k[len(k)-1] = dataType + 1
+	return k, nil
+}
+
+func (db *DB) encodeMetaKey(dataType byte, key []byte) ([]byte, error) {
+	switch dataType {
+	case KVType:
+		return db.encodeKVKey(key), nil
+	case LMetaType:
+		return db.lEncodeMetaKey(key), nil
+	case HSizeType:
+		return db.hEncodeSizeKey(key), nil
+	case ZSizeType:
+		return db.zEncodeSizeKey(key), nil
+	case BitMetaType:
+		return db.bEncodeMetaKey(key), nil
+	case SSizeType:
+		return db.sEncodeSizeKey(key), nil
+	default:
+		return nil, errDataType
+	}
+}
+func (db *DB) decodeMetaKey(dataType byte, ek []byte) ([]byte, error) {
+	if len(ek) < 2 || ek[0] != db.index || ek[1] != dataType {
+		return nil, errMetaKey
+	}
+	return ek[2:], nil
+}
diff --git a/vendor/github.com/lunny/nodb/store/db.go b/vendor/github.com/lunny/nodb/store/db.go
new file mode 100644
index 0000000000..00a8831a67
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/db.go
@@ -0,0 +1,61 @@
+package store
+
+import (
+	"github.com/lunny/nodb/store/driver"
+)
+
+type DB struct {
+	driver.IDB
+}
+
+func (db *DB) NewIterator() *Iterator {
+	it := new(Iterator)
+	it.it = db.IDB.NewIterator()
+
+	return it
+}
+
+func (db *DB) NewWriteBatch() WriteBatch {
+	return db.IDB.NewWriteBatch()
+}
+
+func (db *DB) NewSnapshot() (*Snapshot, error) {
+	var err error
+	s := &Snapshot{}
+	if s.ISnapshot, err = db.IDB.NewSnapshot(); err != nil {
+		return nil, err
+	}
+
+	return s, nil
+}
+
+func (db *DB) RangeIterator(min []byte, max []byte, rangeType uint8) *RangeLimitIterator {
+	return NewRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{0, -1})
+}
+
+func (db *DB) RevRangeIterator(min []byte, max []byte, rangeType uint8) *RangeLimitIterator {
+	return NewRevRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{0, -1})
+}
+
+//count < 0, unlimit.
+//
+//offset must >= 0, if < 0, will get nothing.
+func (db *DB) RangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *RangeLimitIterator {
+	return NewRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{offset, count})
+}
+
+//count < 0, unlimit.
+//
+//offset must >= 0, if < 0, will get nothing.
+func (db *DB) RevRangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *RangeLimitIterator {
+	return NewRevRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{offset, count})
+}
+
+func (db *DB) Begin() (*Tx, error) {
+	tx, err := db.IDB.Begin()
+	if err != nil {
+		return nil, err
+	}
+
+	return &Tx{tx}, nil
+}
diff --git a/vendor/github.com/lunny/nodb/store/driver/batch.go b/vendor/github.com/lunny/nodb/store/driver/batch.go
new file mode 100644
index 0000000000..6b79c21c48
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/driver/batch.go
@@ -0,0 +1,39 @@
+package driver
+
+type BatchPuter interface {
+	BatchPut([]Write) error
+}
+
+type Write struct {
+	Key   []byte
+	Value []byte
+}
+
+type WriteBatch struct {
+	batch BatchPuter
+	wb    []Write
+}
+
+func (w *WriteBatch) Put(key, value []byte) {
+	if value == nil {
+		value = []byte{}
+	}
+	w.wb = append(w.wb, Write{key, value})
+}
+
+func (w *WriteBatch) Delete(key []byte) {
+	w.wb = append(w.wb, Write{key, nil})
+}
+
+func (w *WriteBatch) Commit() error {
+	return w.batch.BatchPut(w.wb)
+}
+
+func (w *WriteBatch) Rollback() error {
+	w.wb = w.wb[0:0]
+	return nil
+}
+
+func NewWriteBatch(puter BatchPuter) IWriteBatch {
+	return &WriteBatch{puter, []Write{}}
+}
diff --git a/vendor/github.com/lunny/nodb/store/driver/driver.go b/vendor/github.com/lunny/nodb/store/driver/driver.go
new file mode 100644
index 0000000000..6da67df083
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/driver/driver.go
@@ -0,0 +1,67 @@
+package driver
+
+import (
+	"errors"
+)
+
+var (
+	ErrTxSupport = errors.New("transaction is not supported")
+)
+
+type IDB interface {
+	Close() error
+
+	Get(key []byte) ([]byte, error)
+
+	Put(key []byte, value []byte) error
+	Delete(key []byte) error
+
+	NewIterator() IIterator
+
+	NewWriteBatch() IWriteBatch
+
+	NewSnapshot() (ISnapshot, error)
+
+	Begin() (Tx, error)
+}
+
+type ISnapshot interface {
+	Get(key []byte) ([]byte, error)
+	NewIterator() IIterator
+	Close()
+}
+
+type IIterator interface {
+	Close() error
+
+	First()
+	Last()
+	Seek(key []byte)
+
+	Next()
+	Prev()
+
+	Valid() bool
+
+	Key() []byte
+	Value() []byte
+}
+
+type IWriteBatch interface {
+	Put(key []byte, value []byte)
+	Delete(key []byte)
+	Commit() error
+	Rollback() error
+}
+
+type Tx interface {
+	Get(key []byte) ([]byte, error)
+	Put(key []byte, value []byte) error
+	Delete(key []byte) error
+
+	NewIterator() IIterator
+	NewWriteBatch() IWriteBatch
+
+	Commit() error
+	Rollback() error
+}
diff --git a/vendor/github.com/lunny/nodb/store/driver/store.go b/vendor/github.com/lunny/nodb/store/driver/store.go
new file mode 100644
index 0000000000..173431d4c1
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/driver/store.go
@@ -0,0 +1,46 @@
+package driver
+
+import (
+	"fmt"
+
+	"github.com/lunny/nodb/config"
+)
+
+type Store interface {
+	String() string
+	Open(path string, cfg *config.Config) (IDB, error)
+	Repair(path string, cfg *config.Config) error
+}
+
+var dbs = map[string]Store{}
+
+func Register(s Store) {
+	name := s.String()
+	if _, ok := dbs[name]; ok {
+		panic(fmt.Errorf("store %s is registered", s))
+	}
+
+	dbs[name] = s
+}
+
+func ListStores() []string {
+	s := []string{}
+	for k, _ := range dbs {
+		s = append(s, k)
+	}
+
+	return s
+}
+
+func GetStore(cfg *config.Config) (Store, error) {
+	if len(cfg.DBName) == 0 {
+		cfg.DBName = config.DefaultDBName
+	}
+
+	s, ok := dbs[cfg.DBName]
+	if !ok {
+		return nil, fmt.Errorf("store %s is not registered", cfg.DBName)
+	}
+
+	return s, nil
+}
diff --git a/vendor/github.com/lunny/nodb/store/goleveldb/batch.go b/vendor/github.com/lunny/nodb/store/goleveldb/batch.go
new file mode 100644
index 0000000000..b17e85e750
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/goleveldb/batch.go
@@ -0,0 +1,27 @@
+package goleveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+type WriteBatch struct {
+	db     *DB
+	wbatch *leveldb.Batch
+}
+
+func (w *WriteBatch) Put(key, value []byte) {
+	w.wbatch.Put(key, value)
+}
+
+func (w *WriteBatch) Delete(key []byte) {
+	w.wbatch.Delete(key)
+}
+
+func (w *WriteBatch) Commit() error {
+	return w.db.db.Write(w.wbatch, nil)
+}
+
+func (w *WriteBatch) Rollback() error {
+	w.wbatch.Reset()
+	return nil
+}
diff --git a/vendor/github.com/lunny/nodb/store/goleveldb/const.go b/vendor/github.com/lunny/nodb/store/goleveldb/const.go
new file mode 100644
index 0000000000..2fffa7c82b
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/goleveldb/const.go
@@ -0,0 +1,4 @@
+package goleveldb
+
+const DBName = "goleveldb"
+const MemDBName = "memory"
diff --git a/vendor/github.com/lunny/nodb/store/goleveldb/db.go b/vendor/github.com/lunny/nodb/store/goleveldb/db.go
new file mode 100644
index 0000000000..a36e87f628
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/goleveldb/db.go
@@ -0,0 +1,187 @@
+package goleveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/cache"
+	"github.com/syndtr/goleveldb/leveldb/filter"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+
+	"github.com/lunny/nodb/config"
+	"github.com/lunny/nodb/store/driver"
+
+	"os"
+)
+
+const defaultFilterBits int = 10
+
+type Store struct {
+}
+
+func (s Store) String() string {
+	return DBName
+}
+
+type MemStore struct {
+}
+
+func (s MemStore) String() string {
+	return MemDBName
+}
+
+type DB struct {
+	path string
+
+	cfg *config.LevelDBConfig
+
+	db *leveldb.DB
+
+	opts *opt.Options
+
+	iteratorOpts *opt.ReadOptions
+
+	cache cache.Cache
+
+	filter filter.Filter
+}
+
+func (s Store) Open(path string, cfg *config.Config) (driver.IDB, error) {
+	if err := os.MkdirAll(path, os.ModePerm); err != nil {
+		return nil, err
+	}
+
+	db := new(DB)
+	db.path = path
+	db.cfg = &cfg.LevelDB
+
+	db.initOpts()
+
+	var err error
+	db.db, err = leveldb.OpenFile(db.path, db.opts)
+
+	if err != nil {
+		return nil, err
+	}
+
+	return db, nil
+}
+
+func (s Store) Repair(path string, cfg *config.Config) error {
+	db, err := leveldb.RecoverFile(path, newOptions(&cfg.LevelDB))
+	if err != nil {
+		return err
+	}
+
+	db.Close()
+	return nil
+}
+
+func (s MemStore) Open(path string, cfg *config.Config) (driver.IDB, error) {
+	db := new(DB)
+	db.path = path
+	db.cfg = &cfg.LevelDB
+
+	db.initOpts()
+
+	var err error
+	db.db, err = leveldb.Open(storage.NewMemStorage(), db.opts)
+	if err != nil {
+		return nil, err
+	}
+
+	return db, nil
+}
+
+func (s MemStore) Repair(path string, cfg *config.Config) error {
+	return nil
+}
+
+func (db *DB) initOpts() {
+	db.opts = newOptions(db.cfg)
+
+	db.iteratorOpts = &opt.ReadOptions{}
+	db.iteratorOpts.DontFillCache = true
+}
+
+func newOptions(cfg *config.LevelDBConfig) *opt.Options {
+	opts := &opt.Options{}
+	opts.ErrorIfMissing = false
+
+	cfg.Adjust()
+
+	//opts.BlockCacher = cache.NewLRU(cfg.CacheSize)
+	opts.BlockCacheCapacity = cfg.CacheSize
+
+	//we must use bloomfilter
+	opts.Filter = filter.NewBloomFilter(defaultFilterBits)
+
+	if !cfg.Compression {
+		opts.Compression = opt.NoCompression
+	} else {
+		opts.Compression = opt.SnappyCompression
+	}
+
+	opts.BlockSize = cfg.BlockSize
+	opts.WriteBuffer = cfg.WriteBufferSize
+
+	return opts
+}
+
+func (db *DB) Close() error {
+	return db.db.Close()
+}
+
+func (db *DB) Put(key, value []byte) error {
+	return db.db.Put(key, value, nil)
+}
+
+func (db *DB) Get(key []byte) ([]byte, error) {
+	v, err := db.db.Get(key, nil)
+	if err == leveldb.ErrNotFound {
+		return nil, nil
+	}
+	return v, nil
+}
+
+func (db *DB) Delete(key []byte) error {
+	return db.db.Delete(key, nil)
+}
+
+func (db *DB) NewWriteBatch() driver.IWriteBatch {
+	wb := &WriteBatch{
+		db:     db,
+		wbatch: new(leveldb.Batch),
+	}
+	return wb
+}
+
+func (db *DB) NewIterator() driver.IIterator {
+	it := &Iterator{
+		db.db.NewIterator(nil, db.iteratorOpts),
+	}
+
+	return it
+}
+
+func (db *DB) Begin() (driver.Tx, error) {
+	return nil, driver.ErrTxSupport
+}
+
+func (db *DB) NewSnapshot() (driver.ISnapshot, error) {
+	snapshot, err := db.db.GetSnapshot()
+	if err != nil {
+		return nil, err
+	}
+
+	s := &Snapshot{
+		db:  db,
+		snp: snapshot,
+	}
+
+	return s, nil
+}
+
+func init() {
+	driver.Register(Store{})
+	driver.Register(MemStore{})
+}
diff --git a/vendor/github.com/lunny/nodb/store/goleveldb/iterator.go b/vendor/github.com/lunny/nodb/store/goleveldb/iterator.go
new file mode 100644
index 0000000000..c1fd8b5573
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/goleveldb/iterator.go
@@ -0,0 +1,49 @@
+package goleveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+)
+
+type Iterator struct {
+	it iterator.Iterator
+}
+
+func (it *Iterator) Key() []byte {
+	return it.it.Key()
+}
+
+func (it *Iterator) Value() []byte {
+	return it.it.Value()
+}
+
+func (it *Iterator) Close() error {
+	if it.it != nil {
+		it.it.Release()
+		it.it = nil
+	}
+	return nil
+}
+
+func (it *Iterator) Valid() bool {
+	return it.it.Valid()
+}
+
+func (it *Iterator) Next() {
+	it.it.Next()
+}
+
+func (it *Iterator) Prev() {
+	it.it.Prev()
+}
+
+func (it *Iterator) First() {
+	it.it.First()
+}
+
+func (it *Iterator) Last() {
+	it.it.Last()
+}
+
+func (it *Iterator) Seek(key []byte) {
+	it.it.Seek(key)
+}
diff --git a/vendor/github.com/lunny/nodb/store/goleveldb/snapshot.go b/vendor/github.com/lunny/nodb/store/goleveldb/snapshot.go
new file mode 100644
index 0000000000..fe2b409c3f
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/goleveldb/snapshot.go
@@ -0,0 +1,26 @@
+package goleveldb
+
+import (
+	"github.com/lunny/nodb/store/driver"
+	"github.com/syndtr/goleveldb/leveldb"
+)
+
+type Snapshot struct {
+	db  *DB
+	snp *leveldb.Snapshot
+}
+
+func (s *Snapshot) Get(key []byte) ([]byte, error) {
+	return s.snp.Get(key, s.db.iteratorOpts)
+}
+
+func (s *Snapshot) NewIterator() driver.IIterator {
+	it := &Iterator{
+		s.snp.NewIterator(nil, s.db.iteratorOpts),
+	}
+	return it
+}
+
+func (s *Snapshot) Close() {
+	s.snp.Release()
+}
diff --git a/vendor/github.com/lunny/nodb/store/iterator.go b/vendor/github.com/lunny/nodb/store/iterator.go
new file mode 100644
index 0000000000..27bf689da2
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/iterator.go
@@ -0,0 +1,327 @@
+package store
+
+import (
+	"bytes"
+
+	"github.com/lunny/nodb/store/driver"
+)
+
+const (
+	IteratorForward  uint8 = 0
+	IteratorBackward uint8 = 1
+)
+
+const (
+	RangeClose uint8 = 0x00
+	RangeLOpen uint8 = 0x01
+	RangeROpen uint8 = 0x10
+	RangeOpen  uint8 = 0x11
+)
+
+// min must less or equal than max
+//
+// range type:
+//
+//  close: [min, max]
+//  open: (min, max)
+//  lopen: (min, max]
+//  ropen: [min, max)
+//
+type Range struct {
+	Min []byte
+	Max []byte
+
+	Type uint8
+}
+
+type Limit struct {
+	Offset int
+	Count  int
+}
+
+type Iterator struct {
+	it driver.IIterator
+}
+
+// Returns a copy of key.
+func (it *Iterator) Key() []byte {
+	k := it.it.Key()
+	if k == nil {
+		return nil
+	}
+
+	return append([]byte{}, k...)
+}
+
+// Returns a copy of value.
+func (it *Iterator) Value() []byte {
+	v := it.it.Value()
+	if v == nil {
+		return nil
+	}
+
+	return append([]byte{}, v...)
+}
+
+// Returns a reference of key.
+// you must be careful that it will be changed after next iterate.
+func (it *Iterator) RawKey() []byte {
+	return it.it.Key()
+}
+
+// Returns a reference of value.
+// you must be careful that it will be changed after next iterate.
+func (it *Iterator) RawValue() []byte {
+	return it.it.Value()
+}
+
+// Copy key to b, if b len is small or nil, returns a new one.
+func (it *Iterator) BufKey(b []byte) []byte {
+	k := it.RawKey()
+	if k == nil {
+		return nil
+	}
+	if b == nil {
+		b = []byte{}
+	}
+
+	b = b[0:0]
+	return append(b, k...)
+}
+
+// Copy value to b, if b len is small or nil, returns a new one.
+func (it *Iterator) BufValue(b []byte) []byte {
+	v := it.RawValue()
+	if v == nil {
+		return nil
+	}
+
+	if b == nil {
+		b = []byte{}
+	}
+
+	b = b[0:0]
+	return append(b, v...)
+}
+
+func (it *Iterator) Close() {
+	if it.it != nil {
+		it.it.Close()
+		it.it = nil
+	}
+}
+
+func (it *Iterator) Valid() bool {
+	return it.it.Valid()
+}
+
+func (it *Iterator) Next() {
+	it.it.Next()
+}
+
+func (it *Iterator) Prev() {
+	it.it.Prev()
+}
+
+func (it *Iterator) SeekToFirst() {
+	it.it.First()
+}
+
+func (it *Iterator) SeekToLast() {
+	it.it.Last()
+}
+
+func (it *Iterator) Seek(key []byte) {
+	it.it.Seek(key)
+}
+
+// Finds by key, if not found, nil returns.
+func (it *Iterator) Find(key []byte) []byte {
+	it.Seek(key)
+	if it.Valid() {
+		k := it.RawKey()
+		if k == nil {
+			return nil
+		} else if bytes.Equal(k, key) {
+			return it.Value()
+		}
+	}
+
+	return nil
+}
+
+// Finds by key, if not found, nil returns, else a reference of value returns.
+// you must be careful that it will be changed after next iterate.
+func (it *Iterator) RawFind(key []byte) []byte {
+	it.Seek(key)
+	if it.Valid() {
+		k := it.RawKey()
+		if k == nil {
+			return nil
+		} else if bytes.Equal(k, key) {
+			return it.RawValue()
+		}
+	}
+
+	return nil
+}
+
+type RangeLimitIterator struct {
+	it *Iterator
+
+	r *Range
+	l *Limit
+
+	step int
+
+	//0 for IteratorForward, 1 for IteratorBackward
+	direction uint8
+}
+
+func (it *RangeLimitIterator) Key() []byte {
+	return it.it.Key()
+}
+
+func (it *RangeLimitIterator) Value() []byte {
+	return it.it.Value()
+}
+
+func (it *RangeLimitIterator) RawKey() []byte {
+	return it.it.RawKey()
+}
+
+func (it *RangeLimitIterator) RawValue() []byte {
+	return it.it.RawValue()
+}
+
+func (it *RangeLimitIterator) BufKey(b []byte) []byte {
+	return it.it.BufKey(b)
+}
+
+func (it *RangeLimitIterator) BufValue(b []byte) []byte {
+	return it.it.BufValue(b)
+}
+
+func (it *RangeLimitIterator) Valid() bool {
+	if it.l.Offset < 0 {
+		return false
+	} else if !it.it.Valid() {
+		return false
+	} else if it.l.Count >= 0 && it.step >= it.l.Count {
+		return false
+	}
+
+	if it.direction == IteratorForward {
+		if it.r.Max != nil {
+			r := bytes.Compare(it.it.RawKey(), it.r.Max)
+			if it.r.Type&RangeROpen > 0 {
+				return !(r >= 0)
+			} else {
+				return !(r > 0)
+			}
+		}
+	} else {
+		if it.r.Min != nil {
+			r := bytes.Compare(it.it.RawKey(), it.r.Min)
+			if it.r.Type&RangeLOpen > 0 {
+				return !(r <= 0)
+			} else {
+				return !(r < 0)
+			}
+		}
+	}
+
+	return true
+}
+
+func (it *RangeLimitIterator) Next() {
+	it.step++
+
+	if it.direction == IteratorForward {
+		it.it.Next()
+	} else {
+		it.it.Prev()
+	}
+}
+
+func (it *RangeLimitIterator) Close() {
+	it.it.Close()
+}
+
+func NewRangeLimitIterator(i *Iterator, r *Range, l *Limit) *RangeLimitIterator {
+	return rangeLimitIterator(i, r, l, IteratorForward)
+}
+
+func NewRevRangeLimitIterator(i *Iterator, r *Range, l *Limit) *RangeLimitIterator {
+	return rangeLimitIterator(i, r, l, IteratorBackward)
+}
+
+func NewRangeIterator(i *Iterator, r *Range) *RangeLimitIterator {
+	return rangeLimitIterator(i, r, &Limit{0, -1}, IteratorForward)
+}
+
+func NewRevRangeIterator(i *Iterator, r *Range) *RangeLimitIterator {
+	return rangeLimitIterator(i, r, &Limit{0, -1}, IteratorBackward)
+}
+
+func rangeLimitIterator(i *Iterator, r *Range, l *Limit, direction uint8) *RangeLimitIterator {
+	it := new(RangeLimitIterator)
+
+	it.it = i
+
+	it.r = r
+	it.l = l
+	it.direction = direction
+
+	it.step = 0
+
+	if l.Offset < 0 {
+		return it
+	}
+
+	if direction == IteratorForward {
+		if r.Min == nil {
+			it.it.SeekToFirst()
+		} else {
+			it.it.Seek(r.Min)
+
+			if r.Type&RangeLOpen > 0 {
+				if it.it.Valid() && bytes.Equal(it.it.RawKey(), r.Min) {
+					it.it.Next()
+				}
+			}
+		}
+	} else {
+		if r.Max == nil {
+			it.it.SeekToLast()
+		} else {
+			it.it.Seek(r.Max)
+
+			if !it.it.Valid() {
+				it.it.SeekToLast()
+			} else {
+				if !bytes.Equal(it.it.RawKey(), r.Max) {
+					it.it.Prev()
+				}
+			}
+
+			if r.Type&RangeROpen > 0 {
+				if it.it.Valid() && bytes.Equal(it.it.RawKey(), r.Max) {
+					it.it.Prev()
+				}
+			}
+		}
+	}
+
+	for i := 0; i < l.Offset; i++ {
+		if it.it.Valid() {
+			if it.direction == IteratorForward {
+				it.it.Next()
+			} else {
+				it.it.Prev()
+			}
+		}
+	}
+
+	return it
+}
diff --git a/vendor/github.com/lunny/nodb/store/snapshot.go b/vendor/github.com/lunny/nodb/store/snapshot.go
new file mode 100644
index 0000000000..75ba0497db
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/snapshot.go
@@ -0,0 +1,16 @@
+package store
+
+import (
+	"github.com/lunny/nodb/store/driver"
+)
+
+type Snapshot struct {
+	driver.ISnapshot
+}
+
+func (s *Snapshot) NewIterator() *Iterator {
+	it := new(Iterator)
+	it.it = s.ISnapshot.NewIterator()
+
+	return it
+}
diff --git a/vendor/github.com/lunny/nodb/store/store.go b/vendor/github.com/lunny/nodb/store/store.go
new file mode 100644
index 0000000000..5d0ade1bf0
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/store.go
@@ -0,0 +1,51 @@
+package store
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"github.com/lunny/nodb/config"
+	"github.com/lunny/nodb/store/driver"
+
+	_ "github.com/lunny/nodb/store/goleveldb"
+)
+
+func getStorePath(cfg *config.Config) string {
+	return path.Join(cfg.DataDir, fmt.Sprintf("%s_data", cfg.DBName))
+}
+
+func Open(cfg *config.Config) (*DB, error) {
+	s, err := driver.GetStore(cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	path := getStorePath(cfg)
+
+	if err := os.MkdirAll(path, os.ModePerm); err != nil {
+		return nil, err
+	}
+
+	idb, err := s.Open(path, cfg)
+	if err != nil {
+		return nil, err
+	}
+
+	db := &DB{idb}
+
+	return db, nil
+}
+
+func Repair(cfg *config.Config) error {
+	s, err := driver.GetStore(cfg)
+	if err != nil {
+		return err
+	}
+
+	path := getStorePath(cfg)
+
+	return s.Repair(path, cfg)
+}
+
+func init() {
+}
diff --git a/vendor/github.com/lunny/nodb/store/tx.go b/vendor/github.com/lunny/nodb/store/tx.go
new file mode 100644
index 0000000000..32bcbcda4b
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/tx.go
@@ -0,0 +1,42 @@
+package store
+
+import (
+	"github.com/lunny/nodb/store/driver"
+)
+
+type Tx struct {
+	driver.Tx
+}
+
+func (tx *Tx) NewIterator() *Iterator {
+	it := new(Iterator)
+	it.it = tx.Tx.NewIterator()
+
+	return it
+}
+
+func (tx *Tx) NewWriteBatch() WriteBatch {
+	return tx.Tx.NewWriteBatch()
+}
+
+func (tx *Tx) RangeIterator(min []byte, max []byte, rangeType uint8) *RangeLimitIterator {
+	return NewRangeLimitIterator(tx.NewIterator(), &Range{min, max, rangeType}, &Limit{0, -1})
+}
+
+func (tx *Tx) RevRangeIterator(min []byte, max []byte, rangeType uint8) *RangeLimitIterator {
+	return NewRevRangeLimitIterator(tx.NewIterator(), &Range{min, max, rangeType}, &Limit{0, -1})
+}
+
+//count < 0, unlimit.
+//
+//offset must >= 0, if < 0, will get nothing.
+func (tx *Tx) RangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *RangeLimitIterator {
+	return NewRangeLimitIterator(tx.NewIterator(), &Range{min, max, rangeType}, &Limit{offset, count})
+}
+
+//count < 0, unlimit.
+//
+//offset must >= 0, if < 0, will get nothing.
+func (tx *Tx) RevRangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *RangeLimitIterator {
+	return NewRevRangeLimitIterator(tx.NewIterator(), &Range{min, max, rangeType}, &Limit{offset, count})
+}
diff --git a/vendor/github.com/lunny/nodb/store/writebatch.go b/vendor/github.com/lunny/nodb/store/writebatch.go
new file mode 100644
index 0000000000..23e079eba6
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/store/writebatch.go
@@ -0,0 +1,9 @@
+package store
+
+import (
+	"github.com/lunny/nodb/store/driver"
+)
+
+type WriteBatch interface {
+	driver.IWriteBatch
+}
diff --git a/vendor/github.com/lunny/nodb/t_bit.go b/vendor/github.com/lunny/nodb/t_bit.go
new file mode 100644
index 0000000000..930d4ba568
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_bit.go
@@ -0,0 +1,922 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"sort"
+	"time"
+
+	"github.com/lunny/nodb/store"
+)
+
+const (
+	OPand uint8 = iota + 1
+	OPor
+	OPxor
+	OPnot
+)
+
+type BitPair struct {
+	Pos int32
+	Val uint8
+}
+
+type segBitInfo struct {
+	Seq uint32
+	Off uint32
+	Val uint8
+}
+
+type segBitInfoArray []segBitInfo
+
+const (
+	// byte
+	segByteWidth uint32 = 9
+	segByteSize  uint32 = 1 << segByteWidth
+
+	// bit
+	segBitWidth uint32 = segByteWidth + 3
+	segBitSize  uint32 = segByteSize << 3
+
+	maxByteSize uint32 = 8 << 20
+	maxSegCount uint32 = maxByteSize / segByteSize
+
+	minSeq uint32 = 0
+	maxSeq uint32 = uint32((maxByteSize << 3) - 1)
+)
+
+var bitsInByte = [256]int32{0, 1, 1, 2, 1, 2, 2, 3, 1, 2, 2, 3, 2, 3, 3,
+	4, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 1, 2, 2, 3, 2, 3,
+	3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4,
+	5, 5, 6, 1, 2, 2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4,
+	3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4,
+	5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 1, 2,
+	2, 3, 2, 3, 3, 4, 2, 3, 3, 4, 3, 4, 4, 5, 2, 3, 3, 4, 3, 4, 4, 5, 3,
+	4, 4, 5, 4, 5, 5, 6, 2, 3, 3, 4, 3, 4, 4, 5, 3, 4, 4, 5, 4, 5, 5, 6,
+	3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 2, 3, 3, 4, 3, 4, 4,
+	5, 3, 4, 4, 5, 4, 5, 5, 6, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6,
+	6, 7, 3, 4, 4, 5, 4, 5, 5, 6, 4, 5, 5, 6, 5, 6, 6, 7, 4, 5, 5, 6, 5,
+	6, 6, 7, 5, 6, 6, 7, 6, 7, 7, 8}
+
+var fillBits = [...]uint8{1, 3, 7, 15, 31, 63, 127, 255}
+
+var emptySegment []byte = make([]byte, segByteSize, segByteSize)
+
+var fillSegment []byte = func() []byte {
+	data := make([]byte, segByteSize, segByteSize)
+	for i := uint32(0); i < segByteSize; i++ {
+		data[i] = 0xff
+	}
+	return data
+}()
+
+var errBinKey = errors.New("invalid bin key")
+var errOffset = errors.New("invalid offset")
+var errDuplicatePos = errors.New("duplicate bit pos")
+
+func getBit(sz []byte, offset uint32) uint8 {
+	index := offset >> 3
+	if index >= uint32(len(sz)) {
+		return 0 // error("overflow")
+	}
+
+	offset -= index << 3
+	return sz[index] >> offset & 1
+}
+
+func setBit(sz []byte, offset uint32, val uint8) bool {
+	if val != 1 && val != 0 {
+		return false // error("invalid val")
+	}
+
+	index := offset >> 3
+	if index >= uint32(len(sz)) {
+		return false // error("overflow")
+	}
+
+	offset -= index << 3
+	if sz[index]>>offset&1 != val {
+		sz[index] ^= (1 << offset)
+	}
+	return true
+}
+
+func (datas segBitInfoArray) Len() int {
+	return len(datas)
+}
+
+func (datas segBitInfoArray) Less(i, j int) bool {
+	res := (datas)[i].Seq < (datas)[j].Seq
+	if !res && (datas)[i].Seq == (datas)[j].Seq {
+		res = (datas)[i].Off < (datas)[j].Off
+	}
+	return res
+}
+
+func (datas segBitInfoArray) Swap(i, j int) {
+	datas[i], datas[j] = datas[j], datas[i]
+}
+
+func (db *DB) bEncodeMetaKey(key []byte) []byte {
+	mk := make([]byte, len(key)+2)
+	mk[0] = db.index
+	mk[1] = BitMetaType
+
+	copy(mk[2:], key)
+	return mk
+}
+
+func (db *DB) bDecodeMetaKey(bkey []byte) ([]byte, error) {
+	if len(bkey) < 2 || bkey[0] != db.index || bkey[1] != BitMetaType {
+		return nil, errBinKey
+	}
+
+	return bkey[2:], nil
+}
+
+func (db *DB) bEncodeBinKey(key []byte, seq uint32) []byte {
+	bk := make([]byte, len(key)+8)
+
+	pos := 0
+	bk[pos] = db.index
+	pos++
+	bk[pos] = BitType
+	pos++
+
+	binary.BigEndian.PutUint16(bk[pos:], uint16(len(key)))
+	pos += 2
+
+	copy(bk[pos:], key)
+	pos += len(key)
+
+	binary.BigEndian.PutUint32(bk[pos:], seq)
+
+	return bk
+}
+
+func (db *DB) bDecodeBinKey(bkey []byte) (key []byte, seq uint32, err error) {
+	if len(bkey) < 8 || bkey[0] != db.index {
+		err = errBinKey
+		return
+	}
+
+	keyLen := binary.BigEndian.Uint16(bkey[2:4])
+	if int(keyLen+8) != len(bkey) {
+		err = errBinKey
+		return
+	}
+
+	key = bkey[4 : 4+keyLen]
+	seq = uint32(binary.BigEndian.Uint32(bkey[4+keyLen:]))
+	return
+}
+
+func (db *DB) bCapByteSize(seq uint32, off uint32) uint32 {
+	var offByteSize uint32 = (off >> 3) + 1
+	if offByteSize > segByteSize {
+		offByteSize = segByteSize
+	}
+
+	return seq<<segByteWidth + offByteSize
+}
+
+func (db *DB) bParseOffset(key []byte, offset int32) (seq uint32, off uint32, err error) {
+	if offset < 0 {
+		if tailSeq, tailOff, e := db.bGetMeta(key); e != nil {
+			err = e
+			return
+		} else if tailSeq >= 0 {
+			offset += int32((uint32(tailSeq)<<segBitWidth | uint32(tailOff)) + 1)
+			if offset < 0 {
+				err = errOffset
+				return
+			}
+		}
+	}
+
+	off = uint32(offset)
+
+	seq = off >> segBitWidth
+	off &= (segBitSize - 1)
+	return
+}
+
+func (db *DB) bGetMeta(key []byte) (tailSeq int32, tailOff int32, err error) {
+	var v []byte
+
+	mk := db.bEncodeMetaKey(key)
+	v, err = db.bucket.Get(mk)
+	if err != nil {
+		return
+	}
+
+	if v != nil {
+		tailSeq = int32(binary.LittleEndian.Uint32(v[0:4]))
+		tailOff = int32(binary.LittleEndian.Uint32(v[4:8]))
+	} else {
+		tailSeq = -1
+		tailOff = -1
+	}
+	return
+}
+
+func (db *DB) bSetMeta(t *batch, key []byte, tailSeq uint32, tailOff uint32) {
+	ek := db.bEncodeMetaKey(key)
+
+	buf := make([]byte, 8)
+	binary.LittleEndian.PutUint32(buf[0:4], tailSeq)
+	binary.LittleEndian.PutUint32(buf[4:8], tailOff)
+
+	t.Put(ek, buf)
+	return
+}
+
+func (db *DB) bUpdateMeta(t *batch, key []byte, seq uint32, off uint32) (tailSeq uint32, tailOff uint32, err error) {
+	var tseq, toff int32
+	var update bool = false
+
+	if tseq, toff, err = db.bGetMeta(key); err != nil {
+		return
+	} else if tseq < 0 {
+		update = true
+	} else {
+		tailSeq = uint32(MaxInt32(tseq, 0))
+		tailOff = uint32(MaxInt32(toff, 0))
+		update = (seq > tailSeq || (seq == tailSeq && off > tailOff))
+	}
+
+	if update {
+		db.bSetMeta(t, key, seq, off)
+		tailSeq = seq
+		tailOff = off
+	}
+	return
+}
+
+func (db *DB) bDelete(t *batch, key []byte) (drop int64) {
+	mk := db.bEncodeMetaKey(key)
+	t.Delete(mk)
+
+	minKey := db.bEncodeBinKey(key, minSeq)
+	maxKey := db.bEncodeBinKey(key, maxSeq)
+	it := db.bucket.RangeIterator(minKey, maxKey, store.RangeClose)
+	for ; it.Valid(); it.Next() {
+		t.Delete(it.RawKey())
+		drop++
+	}
+	it.Close()
+
+	return drop
+}
+
+func (db *DB) bGetSegment(key []byte, seq uint32) ([]byte, []byte, error) {
+	bk := db.bEncodeBinKey(key, seq)
+	segment, err := db.bucket.Get(bk)
+	if err != nil {
+		return bk, nil, err
+	}
+	return bk, segment, nil
+}
+
+func (db *DB) bAllocateSegment(key []byte, seq uint32) ([]byte, []byte, error) {
+	bk, segment, err := db.bGetSegment(key, seq)
+	if err == nil && segment == nil {
+		segment = make([]byte, segByteSize, segByteSize)
+	}
+	return bk, segment, err
+}
+
+func (db *DB) bIterator(key []byte) *store.RangeLimitIterator {
+	sk := db.bEncodeBinKey(key, minSeq)
+	ek := db.bEncodeBinKey(key, maxSeq)
+	return db.bucket.RangeIterator(sk, ek, store.RangeClose)
+}
+
+func (db *DB) bSegAnd(a []byte, b []byte, res *[]byte) {
+	if a == nil || b == nil {
+		*res = nil
+		return
+	}
+
+	data := *res
+	if data == nil {
+		data = make([]byte, segByteSize, segByteSize)
+		*res = data
+	}
+
+	for i := uint32(0); i < segByteSize; i++ {
+		data[i] = a[i] & b[i]
+	}
+	return
+}
+
+func (db *DB) bSegOr(a []byte, b []byte, res *[]byte) {
+	if a == nil || b == nil {
+		if a == nil && b == nil {
+			*res = nil
+		} else if a == nil {
+			*res = b
+		} else {
+			*res = a
+		}
+		return
+	}
+
+	data := *res
+	if data == nil {
+		data = make([]byte, segByteSize, segByteSize)
+		*res = data
+	}
+
+	for i := uint32(0); i < segByteSize; i++ {
+		data[i] = a[i] | b[i]
+	}
+	return
+}
+
+func (db *DB) bSegXor(a []byte, b []byte, res *[]byte) {
+	if a == nil && b == nil {
+		*res = fillSegment
+		return
+	}
+
+	if a == nil {
+		a = emptySegment
+	}
+
+	if b == nil {
+		b = emptySegment
+	}
+
+	data := *res
+	if data == nil {
+		data = make([]byte, segByteSize, segByteSize)
+		*res = data
+	}
+
+	for i := uint32(0); i < segByteSize; i++ {
+		data[i] = a[i] ^ b[i]
+	}
+
+	return
+}
+
+func (db *DB) bExpireAt(key []byte, when int64) (int64, error) {
+	t := db.binBatch
+	t.Lock()
+	defer t.Unlock()
+
+	if seq, _, err := db.bGetMeta(key); err != nil || seq < 0 {
+		return 0, err
+	} else {
+		db.expireAt(t, BitType, key, when)
+		if err := t.Commit(); err != nil {
+			return 0, err
+		}
+	}
+	return 1, nil
+}
+
+func (db *DB) bCountByte(val byte, soff uint32, eoff uint32) int32 {
+	if soff > eoff {
+		soff, eoff = eoff, soff
+	}
+
+	mask := uint8(0)
+	if soff > 0 {
+		mask |= fillBits[soff-1]
+	}
+	if eoff < 7 {
+		mask |= (fillBits[7] ^ fillBits[eoff])
+	}
+	mask = fillBits[7] ^ mask
+
+	return bitsInByte[val&mask]
+}
+
+func (db *DB) bCountSeg(key []byte, seq uint32, soff uint32, eoff uint32) (cnt int32, err error) {
+	if soff >= segBitSize || soff < 0 ||
+		eoff >= segBitSize || eoff < 0 {
+		return
+	}
+
+	var segment []byte
+	if _, segment, err = db.bGetSegment(key, seq); err != nil {
+		return
+	}
+
+	if segment == nil {
+		return
+	}
+
+	if soff > eoff {
+		soff, eoff = eoff, soff
+	}
+
+	headIdx := int(soff >> 3)
+	endIdx := int(eoff >> 3)
+	sByteOff := soff - ((soff >> 3) << 3)
+	eByteOff := eoff - ((eoff >> 3) << 3)
+
+	if headIdx == endIdx {
+		cnt = db.bCountByte(segment[headIdx], sByteOff, eByteOff)
+	} else {
+		cnt = db.bCountByte(segment[headIdx], sByteOff, 7) +
+			db.bCountByte(segment[endIdx], 0, eByteOff)
+	}
+
+	// sum up following bytes
+	for idx, end := headIdx+1, endIdx-1; idx <= end; idx += 1 {
+		cnt += bitsInByte[segment[idx]]
+		if idx == end {
+			break
+		}
+	}
+
+	return
+}
+
+func (db *DB) BGet(key []byte) (data []byte, err error) {
+	if err = checkKeySize(key); err != nil {
+		return
+	}
+
+	var ts, to int32
+	if ts, to, err = db.bGetMeta(key); err != nil || ts < 0 {
+		return
+	}
+
+	var tailSeq, tailOff = uint32(ts), uint32(to)
+	var capByteSize uint32 = db.bCapByteSize(tailSeq, tailOff)
+	data = make([]byte, capByteSize, capByteSize)
+
+	minKey := db.bEncodeBinKey(key, minSeq)
+	maxKey := db.bEncodeBinKey(key, tailSeq)
+	it := db.bucket.RangeIterator(minKey, maxKey, store.RangeClose)
+
+	var seq, s, e uint32
+	for ; it.Valid(); it.Next() {
+		if _, seq, err = db.bDecodeBinKey(it.RawKey()); err != nil {
+			data = nil
+			break
+		}
+
+		s = seq << segByteWidth
+		e = MinUInt32(s+segByteSize, capByteSize)
+		copy(data[s:e], it.RawValue())
+	}
+	it.Close()
+
+	return
+}
+
+func (db *DB) BDelete(key []byte) (drop int64, err error) {
+	if err = checkKeySize(key); err != nil {
+		return
+	}
+
+	t := db.binBatch
+	t.Lock()
+	defer t.Unlock()
+
+	drop = db.bDelete(t, key)
+	db.rmExpire(t, BitType, key)
+
+	err = t.Commit()
+	return
+}
+
+func (db *DB) BSetBit(key []byte, offset int32, val uint8) (ori uint8, err error) {
+	if err = checkKeySize(key); err != nil {
+		return
+	}
+
+	//	todo : check offset
+	var seq, off uint32
+	if seq, off, err = db.bParseOffset(key, offset); err != nil {
+		return 0, err
+	}
+
+	var bk, segment []byte
+	if bk, segment, err = db.bAllocateSegment(key, seq); err != nil {
+		return 0, err
+	}
+
+	if segment != nil {
+		ori = getBit(segment, off)
+		if setBit(segment, off, val) {
+			t := db.binBatch
+			t.Lock()
+			defer t.Unlock()
+
+			t.Put(bk, segment)
+			if _, _, e := db.bUpdateMeta(t, key, seq, off); e != nil {
+				err = e
+				return
+			}
+
+			err = t.Commit()
+		}
+	}
+
+	return
+}
+
+func (db *DB) BMSetBit(key []byte, args ...BitPair) (place int64, err error) {
+	if err = checkKeySize(key); err != nil {
+		return
+	}
+
+	//	(ps : so as to aviod wasting memory copy while calling db.Get() and batch.Put(),
+	//		  here we sequence the params by pos, so that we can merge the execution of
+	//		  diff pos setting which targets on the same segment respectively. )
+
+	//	#1 : sequence request data
+	var argCnt = len(args)
+	var bitInfos segBitInfoArray = make(segBitInfoArray, argCnt)
+	var seq, off uint32
+
+	for i, info := range args {
+		if seq, off, err = db.bParseOffset(key, info.Pos); err != nil {
+			return
+		}
+
+		bitInfos[i].Seq = seq
+		bitInfos[i].Off = off
+		bitInfos[i].Val = info.Val
+	}
+
+	sort.Sort(bitInfos)
+
+	for i := 1; i < argCnt; i++ {
+		if bitInfos[i].Seq == bitInfos[i-1].Seq && bitInfos[i].Off == bitInfos[i-1].Off {
+			return 0, errDuplicatePos
+		}
+	}
+
+	//	#2 : execute bit set in order
+	t := db.binBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var curBinKey, curSeg []byte
+	var curSeq, maxSeq, maxOff uint32
+
+	for _, info := range bitInfos {
+		if curSeg != nil && info.Seq != curSeq {
+			t.Put(curBinKey, curSeg)
+			curSeg = nil
+		}
+
+		if curSeg == nil {
+			curSeq = info.Seq
+			if curBinKey, curSeg, err = db.bAllocateSegment(key, info.Seq); err != nil {
+				return
+			}
+
+			if curSeg == nil {
+				continue
+			}
+		}
+
+		if setBit(curSeg, info.Off, info.Val) {
+			maxSeq = info.Seq
+			maxOff = info.Off
+			place++
+		}
+	}
+
+	if curSeg != nil {
+		t.Put(curBinKey, curSeg)
+	}
+
+	//	finally, update meta
+	if place > 0 {
+		if _, _, err = db.bUpdateMeta(t, key, maxSeq, maxOff); err != nil {
+			return
+		}
+
+		err = t.Commit()
+	}
+
+	return
+}
+
+func (db *DB) BGetBit(key []byte, offset int32) (uint8, error) {
+	if seq, off, err := db.bParseOffset(key, offset); err != nil {
+		return 0, err
+	} else {
+		_, segment, err := db.bGetSegment(key, seq)
+		if err != nil {
+			return 0, err
+		}
+
+		if segment == nil {
+			return 0, nil
+		} else {
+			return getBit(segment, off), nil
+		}
+	}
+}
+
+// func (db *DB) BGetRange(key []byte, start int32, end int32) ([]byte, error) {
+// 	section := make([]byte)
+
+// 	return
+// }
+
+func (db *DB) BCount(key []byte, start int32, end int32) (cnt int32, err error) {
+	var sseq, soff uint32
+	if sseq, soff, err = db.bParseOffset(key, start); err != nil {
+		return
+	}
+
+	var eseq, eoff uint32
+	if eseq, eoff, err = db.bParseOffset(key, end); err != nil {
+		return
+	}
+
+	if sseq > eseq || (sseq == eseq && soff > eoff) {
+		sseq, eseq = eseq, sseq
+		soff, eoff = eoff, soff
+	}
+
+	var segCnt int32
+	if eseq == sseq {
+		if segCnt, err = db.bCountSeg(key, sseq, soff, eoff); err != nil {
+			return 0, err
+		}
+
+		cnt = segCnt
+
+	} else {
+		if segCnt, err = db.bCountSeg(key, sseq, soff, segBitSize-1); err != nil {
+			return 0, err
+		} else {
+			cnt += segCnt
+		}
+
+		if segCnt, err = db.bCountSeg(key, eseq, 0, eoff); err != nil {
+			return 0, err
+		} else {
+			cnt += segCnt
+		}
+	}
+
+	//	middle segs
+	var segment []byte
+	skey := db.bEncodeBinKey(key, sseq)
+	ekey := db.bEncodeBinKey(key, eseq)
+
+	it := db.bucket.RangeIterator(skey, ekey, store.RangeOpen)
+	for ; it.Valid(); it.Next() {
+		segment = it.RawValue()
+		for _, bt := range segment {
+			cnt += bitsInByte[bt]
+		}
+	}
+	it.Close()
+
+	return
+}
+
+func (db *DB) BTail(key []byte) (int32, error) {
+	// effective length of data, the highest bit-pos set in history
+	tailSeq, tailOff, err := db.bGetMeta(key)
+	if err != nil {
+		return 0, err
+	}
+
+	tail := int32(-1)
+	if tailSeq >= 0 {
+		tail = int32(uint32(tailSeq)<<segBitWidth | uint32(tailOff))
+	}
+
+	return tail, nil
+}
+
+func (db *DB) BOperation(op uint8, dstkey []byte, srckeys ...[]byte) (blen int32, err error) {
+	//	blen -
+	//		the total bit size of data stored in destination key,
+	//		that is equal to the size of the longest input string.
+
+	var exeOp func([]byte, []byte, *[]byte)
+	switch op {
+	case OPand:
+		exeOp = db.bSegAnd
+	case OPor:
+		exeOp = db.bSegOr
+	case OPxor, OPnot:
+		exeOp = db.bSegXor
+	default:
+		return
+	}
+
+	if dstkey == nil || srckeys == nil {
+		return
+	}
+
+	t := db.binBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var srcKseq, srcKoff int32
+	var seq, off, maxDstSeq, maxDstOff uint32
+
+	var keyNum int = len(srckeys)
+	var validKeyNum int
+	for i := 0; i < keyNum; i++ {
+		if srcKseq, srcKoff, err = db.bGetMeta(srckeys[i]); err != nil {
+			return
+		} else if srcKseq < 0 {
+			srckeys[i] = nil
+			continue
+		}
+
+		validKeyNum++
+
+		seq = uint32(srcKseq)
+		off = uint32(srcKoff)
+		if seq > maxDstSeq || (seq == maxDstSeq && off > maxDstOff) {
+			maxDstSeq = seq
+			maxDstOff = off
+		}
+	}
+
+	if (op == OPnot && validKeyNum != 1) ||
+		(op != OPnot && validKeyNum < 2) {
+		return // with not enough existing source key
+	}
+
+	var srcIdx int
+	for srcIdx = 0; srcIdx < keyNum; srcIdx++ {
+		if srckeys[srcIdx] != nil {
+			break
+		}
+	}
+
+	// init - data
+	var segments = make([][]byte, maxDstSeq+1)
+
+	if op == OPnot {
+		//	ps :
+		//		( ~num == num ^ 0x11111111 )
+		//		we init the result segments with all bit set,
+		//		then we can calculate through the way of 'xor'.
+
+		//	ahead segments bin format : 1111 ... 1111
+		for i := uint32(0); i < maxDstSeq; i++ {
+			segments[i] = fillSegment
+		}
+
+		//	last segment bin format : 1111..1100..0000
+		var tailSeg = make([]byte, segByteSize, segByteSize)
+		var fillByte = fillBits[7]
+		var tailSegLen = db.bCapByteSize(uint32(0), maxDstOff)
+		for i := uint32(0); i < tailSegLen-1; i++ {
+			tailSeg[i] = fillByte
+		}
+		tailSeg[tailSegLen-1] = fillBits[maxDstOff-(tailSegLen-1)<<3]
+		segments[maxDstSeq] = tailSeg
+
+	} else {
+		// ps : init segments by data corresponding to the 1st valid source key
+		it := db.bIterator(srckeys[srcIdx])
+		for ; it.Valid(); it.Next() {
+			if _, seq, err = db.bDecodeBinKey(it.RawKey()); err != nil {
+				// to do ...
+				it.Close()
+				return
+			}
+			segments[seq] = it.Value()
+		}
+		it.Close()
+		srcIdx++
+	}
+
+	//	operation with following keys
+	var res []byte
+	for i := srcIdx; i < keyNum; i++ {
+		if srckeys[i] == nil {
+			continue
+		}
+
+		it := db.bIterator(srckeys[i])
+		for idx, end := uint32(0), false; !end; it.Next() {
+			end = !it.Valid()
+			if !end {
+				if _, seq, err = db.bDecodeBinKey(it.RawKey()); err != nil {
+					// to do ...
+					it.Close()
+					return
+				}
+			} else {
+				seq = maxDstSeq + 1
+			}
+
+			// todo :
+			// 		operation 'and' can be optimize here :
+			//		if seq > max_segments_idx, this loop can be break,
+			//		which can avoid cost from Key() and bDecodeBinKey()
+
+			for ; idx < seq; idx++ {
+				res = nil
+				exeOp(segments[idx], nil, &res)
+				segments[idx] = res
+			}
+
+			if !end {
+				res = it.Value()
+				exeOp(segments[seq], res, &res)
+				segments[seq] = res
+				idx++
+			}
+		}
+		it.Close()
+	}
+
+	// clear the old data in case
+	db.bDelete(t, dstkey)
+	db.rmExpire(t, BitType, dstkey)
+
+	//	set data
+	db.bSetMeta(t, dstkey, maxDstSeq, maxDstOff)
+
+	var bk []byte
+	for seq, segt := range segments {
+		if segt != nil {
+			bk = db.bEncodeBinKey(dstkey, uint32(seq))
+			t.Put(bk, segt)
+		}
+	}
+
+	err = t.Commit()
+	if err == nil {
+		// blen = int32(db.bCapByteSize(maxDstOff, maxDstOff))
+		blen = int32(maxDstSeq<<segBitWidth | maxDstOff + 1)
+	}
+
+	return
+}
+
+func (db *DB) BExpire(key []byte, duration int64) (int64, error) {
+	if duration <= 0 {
+		return 0, errExpireValue
+	}
+
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.bExpireAt(key, time.Now().Unix()+duration)
+}
+
+func (db *DB) BExpireAt(key []byte, when int64) (int64, error) {
+	if when <= time.Now().Unix() {
+		return 0, errExpireValue
+	}
+
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.bExpireAt(key, when)
+}
+
+func (db *DB) BTTL(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.ttl(BitType, key)
+}
+
+func (db *DB) BPersist(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.binBatch
+	t.Lock()
+	defer t.Unlock()
+
+	n, err := db.rmExpire(t, BitType, key)
+	if err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return n, err
+}
+
+func (db *DB) BScan(key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	return db.scan(BitMetaType, key, count, inclusive, match)
+}
+
+func (db *DB) bFlush() (drop int64, err error) {
+	t := db.binBatch
+	t.Lock()
+	defer t.Unlock()
+
+	return db.flushType(t, BitType)
+}
diff --git a/vendor/github.com/lunny/nodb/t_hash.go b/vendor/github.com/lunny/nodb/t_hash.go
new file mode 100644
index 0000000000..bedfbf7c3e
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_hash.go
@@ -0,0 +1,509 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"time"
+
+	"github.com/lunny/nodb/store"
+)
+
+type FVPair struct {
+	Field []byte
+	Value []byte
+}
+
+var errHashKey = errors.New("invalid hash key")
+var errHSizeKey = errors.New("invalid hsize key")
+
+const (
+	hashStartSep byte = ':'
+	hashStopSep  byte = hashStartSep + 1
+)
+
+func checkHashKFSize(key []byte, field []byte) error {
+	if len(key) > MaxKeySize || len(key) == 0 {
+		return errKeySize
+	} else if len(field) > MaxHashFieldSize || len(field) == 0 {
+		return errHashFieldSize
+	}
+	return nil
+}
+
+func (db *DB) hEncodeSizeKey(key []byte) []byte {
+	buf := make([]byte, len(key)+2)
+
+	buf[0] = db.index
+	buf[1] = HSizeType
+
+	copy(buf[2:], key)
+	return buf
+}
+
+func (db *DB) hDecodeSizeKey(ek []byte) ([]byte, error) {
+	if len(ek) < 2 || ek[0] != db.index || ek[1] != HSizeType {
+		return nil, errHSizeKey
+	}
+
+	return ek[2:], nil
+}
+
+func (db *DB) hEncodeHashKey(key []byte, field []byte) []byte {
+	buf := make([]byte, len(key)+len(field)+1+1+2+1)
+
+	pos := 0
+	buf[pos] = db.index
+	pos++
+	buf[pos] = HashType
+	pos++
+
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+	pos += 2
+
+	copy(buf[pos:], key)
+	pos += len(key)
+
+	buf[pos] = hashStartSep
+	pos++
+	copy(buf[pos:], field)
+
+	return buf
+}
+
+func (db *DB) hDecodeHashKey(ek []byte) ([]byte, []byte, error) {
+	if len(ek) < 5 || ek[0] != db.index || ek[1] != HashType {
+		return nil, nil, errHashKey
+	}
+
+	pos := 2
+	keyLen := int(binary.BigEndian.Uint16(ek[pos:]))
+	pos += 2
+
+	if keyLen+5 > len(ek) {
+		return nil, nil, errHashKey
+	}
+
+	key := ek[pos : pos+keyLen]
+	pos += keyLen
+
+	if ek[pos] != hashStartSep {
+		return nil, nil, errHashKey
+	}
+
+	pos++
+	field := ek[pos:]
+	return key, field, nil
+}
+
+func (db *DB) hEncodeStartKey(key []byte) []byte {
+	return db.hEncodeHashKey(key, nil)
+}
+
+func (db *DB) hEncodeStopKey(key []byte) []byte {
+	k := db.hEncodeHashKey(key, nil)
+
+	k[len(k)-1] = hashStopSep
+
+	return k
+}
+
+func (db *DB) hSetItem(key []byte, field []byte, value []byte) (int64, error) {
+	t := db.hashBatch
+
+	ek := db.hEncodeHashKey(key, field)
+
+	var n int64 = 1
+	if v, _ := db.bucket.Get(ek); v != nil {
+		n = 0
+	} else {
+		if _, err := db.hIncrSize(key, 1); err != nil {
+			return 0, err
+		}
+	}
+
+	t.Put(ek, value)
+	return n, nil
+}
+
+//	ps : here just focus on deleting the hash data,
+//		 any other likes expire is ignore.
+func (db *DB) hDelete(t *batch, key []byte) int64 {
+	sk := db.hEncodeSizeKey(key)
+	start := db.hEncodeStartKey(key)
+	stop := db.hEncodeStopKey(key)
+
+	var num int64 = 0
+	it := db.bucket.RangeLimitIterator(start, stop, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		t.Delete(it.Key())
+		num++
+	}
+	it.Close()
+
+	t.Delete(sk)
+	return num
+}
+
+func (db *DB) hExpireAt(key []byte, when int64) (int64, error) {
+	t := db.hashBatch
+	t.Lock()
+	defer t.Unlock()
+
+	if hlen, err := db.HLen(key); err != nil || hlen == 0 {
+		return 0, err
+	} else {
+		db.expireAt(t, HashType, key, when)
+		if err := t.Commit(); err != nil {
+			return 0, err
+		}
+	}
+	return 1, nil
+}
+
+func (db *DB) HLen(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	return Int64(db.bucket.Get(db.hEncodeSizeKey(key)))
+}
+
+func (db *DB) HSet(key []byte, field []byte, value []byte) (int64, error) {
+	if err := checkHashKFSize(key, field); err != nil {
+		return 0, err
+	} else if err := checkValueSize(value); err != nil {
+		return 0, err
+	}
+
+	t := db.hashBatch
+	t.Lock()
+	defer t.Unlock()
+
+	n, err := db.hSetItem(key, field, value)
+	if err != nil {
+		return 0, err
+	}
+
+	//todo add binlog
+
+	err = t.Commit()
+	return n, err
+}
+
+func (db *DB) HGet(key []byte, field []byte) ([]byte, error) {
+	if err := checkHashKFSize(key, field); err != nil {
+		return nil, err
+	}
+
+	return db.bucket.Get(db.hEncodeHashKey(key, field))
+}
+
+func (db *DB) HMset(key []byte, args ...FVPair) error {
+	t := db.hashBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var err error
+	var ek []byte
+	var num int64 = 0
+	for i := 0; i < len(args); i++ {
+		if err := checkHashKFSize(key, args[i].Field); err != nil {
+			return err
+		} else if err := checkValueSize(args[i].Value); err != nil {
+			return err
+		}
+
+		ek = db.hEncodeHashKey(key, args[i].Field)
+
+		if v, err := db.bucket.Get(ek); err != nil {
+			return err
+		} else if v == nil {
+			num++
+		}
+
+		t.Put(ek, args[i].Value)
+	}
+
+	if _, err = db.hIncrSize(key, num); err != nil {
+		return err
+	}
+
+	//todo add binglog
+	err = t.Commit()
+	return err
+}
+
+func (db *DB) HMget(key []byte, args ...[]byte) ([][]byte, error) {
+	var ek []byte
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	r := make([][]byte, len(args))
+	for i := 0; i < len(args); i++ {
+		if err := checkHashKFSize(key, args[i]); err != nil {
+			return nil, err
+		}
+
+		ek = db.hEncodeHashKey(key, args[i])
+
+		r[i] = it.Find(ek)
+	}
+
+	return r, nil
+}
+
+func (db *DB) HDel(key []byte, args ...[]byte) (int64, error) {
+	t := db.hashBatch
+
+	var ek []byte
+	var v []byte
+	var err error
+
+	t.Lock()
+	defer t.Unlock()
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	var num int64 = 0
+	for i := 0; i < len(args); i++ {
+		if err := checkHashKFSize(key, args[i]); err != nil {
+			return 0, err
+		}
+
+		ek = db.hEncodeHashKey(key, args[i])
+
+		v = it.RawFind(ek)
+		if v == nil {
+			continue
+		} else {
+			num++
+			t.Delete(ek)
+		}
+	}
+
+	if _, err = db.hIncrSize(key, -num); err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+
+	return num, err
+}
+
+func (db *DB) hIncrSize(key []byte, delta int64) (int64, error) {
+	t := db.hashBatch
+	sk := db.hEncodeSizeKey(key)
+
+	var err error
+	var size int64 = 0
+	if size, err = Int64(db.bucket.Get(sk)); err != nil {
+		return 0, err
+	} else {
+		size += delta
+		if size <= 0 {
+			size = 0
+			t.Delete(sk)
+			db.rmExpire(t, HashType, key)
+		} else {
+			t.Put(sk, PutInt64(size))
+		}
+	}
+
+	return size, nil
+}
+
+func (db *DB) HIncrBy(key []byte, field []byte, delta int64) (int64, error) {
+	if err := checkHashKFSize(key, field); err != nil {
+		return 0, err
+	}
+
+	t := db.hashBatch
+	var ek []byte
+	var err error
+
+	t.Lock()
+	defer t.Unlock()
+
+	ek = db.hEncodeHashKey(key, field)
+
+	var n int64 = 0
+	if n, err = StrInt64(db.bucket.Get(ek)); err != nil {
+		return 0, err
+	}
+
+	n += delta
+
+	_, err = db.hSetItem(key, field, StrPutInt64(n))
+	if err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+
+	return n, err
+}
+
+func (db *DB) HGetAll(key []byte) ([]FVPair, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	start := db.hEncodeStartKey(key)
+	stop := db.hEncodeStopKey(key)
+
+	v := make([]FVPair, 0, 16)
+
+	it := db.bucket.RangeLimitIterator(start, stop, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		_, f, err := db.hDecodeHashKey(it.Key())
+		if err != nil {
+			return nil, err
+		}
+
+		v = append(v, FVPair{Field: f, Value: it.Value()})
+	}
+
+	it.Close()
+
+	return v, nil
+}
+
+func (db *DB) HKeys(key []byte) ([][]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	start := db.hEncodeStartKey(key)
+	stop := db.hEncodeStopKey(key)
+
+	v := make([][]byte, 0, 16)
+
+	it := db.bucket.RangeLimitIterator(start, stop, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		_, f, err := db.hDecodeHashKey(it.Key())
+		if err != nil {
+			return nil, err
+		}
+		v = append(v, f)
+	}
+
+	it.Close()
+
+	return v, nil
+}
+
+func (db *DB) HValues(key []byte) ([][]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	start := db.hEncodeStartKey(key)
+	stop := db.hEncodeStopKey(key)
+
+	v := make([][]byte, 0, 16)
+
+	it := db.bucket.RangeLimitIterator(start, stop, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		_, _, err := db.hDecodeHashKey(it.Key())
+		if err != nil {
+			return nil, err
+		}
+
+		v = append(v, it.Value())
+	}
+
+	it.Close()
+
+	return v, nil
+}
+
+func (db *DB) HClear(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.hashBatch
+	t.Lock()
+	defer t.Unlock()
+
+	num := db.hDelete(t, key)
+	db.rmExpire(t, HashType, key)
+
+	err := t.Commit()
+	return num, err
+}
+
+func (db *DB) HMclear(keys ...[]byte) (int64, error) {
+	t := db.hashBatch
+	t.Lock()
+	defer t.Unlock()
+
+	for _, key := range keys {
+		if err := checkKeySize(key); err != nil {
+			return 0, err
+		}
+
+		db.hDelete(t, key)
+		db.rmExpire(t, HashType, key)
+	}
+
+	err := t.Commit()
+	return int64(len(keys)), err
+}
+
+func (db *DB) hFlush() (drop int64, err error) {
+	t := db.hashBatch
+
+	t.Lock()
+	defer t.Unlock()
+
+	return db.flushType(t, HashType)
+}
+
+func (db *DB) HScan(key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	return db.scan(HSizeType, key, count, inclusive, match)
+}
+
+func (db *DB) HExpire(key []byte, duration int64) (int64, error) {
+	if duration <= 0 {
+		return 0, errExpireValue
+	}
+
+	return db.hExpireAt(key, time.Now().Unix()+duration)
+}
+
+func (db *DB) HExpireAt(key []byte, when int64) (int64, error) {
+	if when <= time.Now().Unix() {
+		return 0, errExpireValue
+	}
+
+	return db.hExpireAt(key, when)
+}
+
+func (db *DB) HTTL(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.ttl(HashType, key)
+}
+
+func (db *DB) HPersist(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.hashBatch
+	t.Lock()
+	defer t.Unlock()
+
+	n, err := db.rmExpire(t, HashType, key)
+	if err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return n, err
+}
diff --git a/vendor/github.com/lunny/nodb/t_kv.go b/vendor/github.com/lunny/nodb/t_kv.go
new file mode 100644
index 0000000000..82a12f7027
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_kv.go
@@ -0,0 +1,387 @@
+package nodb
+
+import (
+	"errors"
+	"time"
+)
+
+type KVPair struct {
+	Key   []byte
+	Value []byte
+}
+
+var errKVKey = errors.New("invalid encode kv key")
+
+func checkKeySize(key []byte) error {
+	if len(key) > MaxKeySize || len(key) == 0 {
+		return errKeySize
+	}
+	return nil
+}
+
+func checkValueSize(value []byte) error {
+	if len(value) > MaxValueSize {
+		return errValueSize
+	}
+
+	return nil
+}
+
+func (db *DB) encodeKVKey(key []byte) []byte {
+	ek := make([]byte, len(key)+2)
+	ek[0] = db.index
+	ek[1] = KVType
+	copy(ek[2:], key)
+	return ek
+}
+
+func (db *DB) decodeKVKey(ek []byte) ([]byte, error) {
+	if len(ek) < 2 || ek[0] != db.index || ek[1] != KVType {
+		return nil, errKVKey
+	}
+
+	return ek[2:], nil
+}
+
+func (db *DB) encodeKVMinKey() []byte {
+	ek := db.encodeKVKey(nil)
+	return ek
+}
+
+func (db *DB) encodeKVMaxKey() []byte {
+	ek := db.encodeKVKey(nil)
+	ek[len(ek)-1] = KVType + 1
+	return ek
+}
+
+func (db *DB) incr(key []byte, delta int64) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	var err error
+	key = db.encodeKVKey(key)
+
+	t := db.kvBatch
+
+	t.Lock()
+	defer t.Unlock()
+
+	var n int64
+	n, err = StrInt64(db.bucket.Get(key))
+	if err != nil {
+		return 0, err
+	}
+
+	n += delta
+
+	t.Put(key, StrPutInt64(n))
+
+	//todo binlog
+
+	err = t.Commit()
+	return n, err
+}
+
+//	ps : here just focus on deleting the key-value data,
+//		 any other likes expire is ignore.
+func (db *DB) delete(t *batch, key []byte) int64 {
+	key = db.encodeKVKey(key)
+	t.Delete(key)
+	return 1
+}
+
+func (db *DB) setExpireAt(key []byte, when int64) (int64, error) {
+	t := db.kvBatch
+	t.Lock()
+	defer t.Unlock()
+
+	if exist, err := db.Exists(key); err != nil || exist == 0 {
+		return 0, err
+	} else {
+		db.expireAt(t, KVType, key, when)
+		if err := t.Commit(); err != nil {
+			return 0, err
+		}
+	}
+	return 1, nil
+}
+
+func (db *DB) Decr(key []byte) (int64, error) {
+	return db.incr(key, -1)
+}
+
+func (db *DB) DecrBy(key []byte, decrement int64) (int64, error) {
+	return db.incr(key, -decrement)
+}
+
+func (db *DB) Del(keys ...[]byte) (int64, error) {
+	if len(keys) == 0 {
+		return 0, nil
+	}
+
+	codedKeys := make([][]byte, len(keys))
+	for i, k := range keys {
+		codedKeys[i] = db.encodeKVKey(k)
+	}
+
+	t := db.kvBatch
+	t.Lock()
+	defer t.Unlock()
+
+	for i, k := range keys {
+		t.Delete(codedKeys[i])
+		db.rmExpire(t, KVType, k)
+	}
+
+	err := t.Commit()
+	return int64(len(keys)), err
+}
+
+func (db *DB) Exists(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	var err error
+	key = db.encodeKVKey(key)
+
+	var v []byte
+	v, err = db.bucket.Get(key)
+	if v != nil && err == nil {
+		return 1, nil
+	}
+
+	return 0, err
+}
+
+func (db *DB) Get(key []byte) ([]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	key = db.encodeKVKey(key)
+
+	return db.bucket.Get(key)
+}
+
+func (db *DB) GetSet(key []byte, value []byte) ([]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	} else if err := checkValueSize(value); err != nil {
+		return nil, err
+	}
+
+	key = db.encodeKVKey(key)
+
+	t := db.kvBatch
+
+	t.Lock()
+	defer t.Unlock()
+
+	oldValue, err := db.bucket.Get(key)
+	if err != nil {
+		return nil, err
+	}
+
+	t.Put(key, value)
+	//todo, binlog
+
+	err = t.Commit()
+
+	return oldValue, err
+}
+
+func (db *DB) Incr(key []byte) (int64, error) {
+	return db.incr(key, 1)
+}
+
+func (db *DB) IncrBy(key []byte, increment int64) (int64, error) {
+	return db.incr(key, increment)
+}
+
+func (db *DB) MGet(keys ...[]byte) ([][]byte, error) {
+	values := make([][]byte, len(keys))
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	for i := range keys {
+		if err := checkKeySize(keys[i]); err != nil {
+			return nil, err
+		}
+
+		values[i] = it.Find(db.encodeKVKey(keys[i]))
+	}
+
+	return values, nil
+}
+
+func (db *DB) MSet(args ...KVPair) error {
+	if len(args) == 0 {
+		return nil
+	}
+
+	t := db.kvBatch
+
+	var err error
+	var key []byte
+	var value []byte
+
+	t.Lock()
+	defer t.Unlock()
+
+	for i := 0; i < len(args); i++ {
+		if err := checkKeySize(args[i].Key); err != nil {
+			return err
+		} else if err := checkValueSize(args[i].Value); err != nil {
+			return err
+		}
+
+		key = db.encodeKVKey(args[i].Key)
+
+		value = args[i].Value
+
+		t.Put(key, value)
+
+		//todo binlog
+	}
+
+	err = t.Commit()
+	return err
+}
+
+func (db *DB) Set(key []byte, value []byte) error {
+	if err := checkKeySize(key); err != nil {
+		return err
+	} else if err := checkValueSize(value); err != nil {
+		return err
+	}
+
+	var err error
+	key = db.encodeKVKey(key)
+
+	t := db.kvBatch
+
+	t.Lock()
+	defer t.Unlock()
+
+	t.Put(key, value)
+
+	err = t.Commit()
+
+	return err
+}
+
+func (db *DB) SetNX(key []byte, value []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	} else if err := checkValueSize(value); err != nil {
+		return 0, err
+	}
+
+	var err error
+	key = db.encodeKVKey(key)
+
+	var n int64 = 1
+
+	t := db.kvBatch
+
+	t.Lock()
+	defer t.Unlock()
+
+	if v, err := db.bucket.Get(key); err != nil {
+		return 0, err
+	} else if v != nil {
+		n = 0
+	} else {
+		t.Put(key, value)
+
+		//todo binlog
+
+		err = t.Commit()
+	}
+
+	return n, err
+}
+
+func (db *DB) flush() (drop int64, err error) {
+	t := db.kvBatch
+	t.Lock()
+	defer t.Unlock()
+	return db.flushType(t, KVType)
+}
+
+//if inclusive is true, scan range [key, inf) else (key, inf)
+func (db *DB) Scan(key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	return db.scan(KVType, key, count, inclusive, match)
+}
+
+func (db *DB) Expire(key []byte, duration int64) (int64, error) {
+	if duration <= 0 {
+		return 0, errExpireValue
+	}
+
+	return db.setExpireAt(key, time.Now().Unix()+duration)
+}
+
+func (db *DB) ExpireAt(key []byte, when int64) (int64, error) {
+	if when <= time.Now().Unix() {
+		return 0, errExpireValue
+	}
+
+	return db.setExpireAt(key, when)
+}
+
+func (db *DB) TTL(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.ttl(KVType, key)
+}
+
+func (db *DB) Persist(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.kvBatch
+	t.Lock()
+	defer t.Unlock()
+	n, err := db.rmExpire(t, KVType, key)
+	if err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return n, err
+}
+
+func (db *DB) Lock() {
+	t := db.kvBatch
+	t.Lock()
+}
+
+func (db *DB) Remove(key []byte) bool {
+	if len(key) == 0 {
+		return false
+	}
+	t := db.kvBatch
+	t.Delete(db.encodeKVKey(key))
+	_, err := db.rmExpire(t, KVType, key)
+	if err != nil {
+		return false
+	}
+	return true
+}
+
+func (db *DB) Commit() error {
+	t := db.kvBatch
+	return t.Commit()
+}
+
+func (db *DB) Unlock() {
+	t := db.kvBatch
+	t.Unlock()
+}
diff --git a/vendor/github.com/lunny/nodb/t_list.go b/vendor/github.com/lunny/nodb/t_list.go
new file mode 100644
index 0000000000..5b9d9d9c21
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_list.go
@@ -0,0 +1,492 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"time"
+
+	"github.com/lunny/nodb/store"
+)
+
+const (
+	listHeadSeq int32 = 1
+	listTailSeq int32 = 2
+
+	listMinSeq     int32 = 1000
+	listMaxSeq     int32 = 1<<31 - 1000
+	listInitialSeq int32 = listMinSeq + (listMaxSeq-listMinSeq)/2
+)
+
+var errLMetaKey = errors.New("invalid lmeta key")
+var errListKey = errors.New("invalid list key")
+var errListSeq = errors.New("invalid list sequence, overflow")
+
+func (db *DB) lEncodeMetaKey(key []byte) []byte {
+	buf := make([]byte, len(key)+2)
+	buf[0] = db.index
+	buf[1] = LMetaType
+
+	copy(buf[2:], key)
+	return buf
+}
+
+func (db *DB) lDecodeMetaKey(ek []byte) ([]byte, error) {
+	if len(ek) < 2 || ek[0] != db.index || ek[1] != LMetaType {
+		return nil, errLMetaKey
+	}
+
+	return ek[2:], nil
+}
+
+func (db *DB) lEncodeListKey(key []byte, seq int32) []byte {
+	buf := make([]byte, len(key)+8)
+
+	pos := 0
+	buf[pos] = db.index
+	pos++
+	buf[pos] = ListType
+	pos++
+
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+	pos += 2
+
+	copy(buf[pos:], key)
+	pos += len(key)
+
+	binary.BigEndian.PutUint32(buf[pos:], uint32(seq))
+
+	return buf
+}
+
+func (db *DB) lDecodeListKey(ek []byte) (key []byte, seq int32, err error) {
+	if len(ek) < 8 || ek[0] != db.index || ek[1] != ListType {
+		err = errListKey
+		return
+	}
+
+	keyLen := int(binary.BigEndian.Uint16(ek[2:]))
+	if keyLen+8 != len(ek) {
+		err = errListKey
+		return
+	}
+
+	key = ek[4 : 4+keyLen]
+	seq = int32(binary.BigEndian.Uint32(ek[4+keyLen:]))
+	return
+}
+
+func (db *DB) lpush(key []byte, whereSeq int32, args ...[]byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	var headSeq int32
+	var tailSeq int32
+	var size int32
+	var err error
+
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+
+	metaKey := db.lEncodeMetaKey(key)
+	headSeq, tailSeq, size, err = db.lGetMeta(nil, metaKey)
+	if err != nil {
+		return 0, err
+	}
+
+	var pushCnt int = len(args)
+	if pushCnt == 0 {
+		return int64(size), nil
+	}
+
+	var seq int32 = headSeq
+	var delta int32 = -1
+	if whereSeq == listTailSeq {
+		seq = tailSeq
+		delta = 1
+	}
+
+	//	append elements
+	if size > 0 {
+		seq += delta
+	}
+
+	for i := 0; i < pushCnt; i++ {
+		ek := db.lEncodeListKey(key, seq+int32(i)*delta)
+		t.Put(ek, args[i])
+	}
+
+	seq += int32(pushCnt-1) * delta
+	if seq <= listMinSeq || seq >= listMaxSeq {
+		return 0, errListSeq
+	}
+
+	//	set meta info
+	if whereSeq == listHeadSeq {
+		headSeq = seq
+	} else {
+		tailSeq = seq
+	}
+
+	db.lSetMeta(metaKey, headSeq, tailSeq)
+
+	err = t.Commit()
+	return int64(size) + int64(pushCnt), err
+}
+
+func (db *DB) lpop(key []byte, whereSeq int32) ([]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var headSeq int32
+	var tailSeq int32
+	var err error
+
+	metaKey := db.lEncodeMetaKey(key)
+	headSeq, tailSeq, _, err = db.lGetMeta(nil, metaKey)
+	if err != nil {
+		return nil, err
+	}
+
+	var value []byte
+
+	var seq int32 = headSeq
+	if whereSeq == listTailSeq {
+		seq = tailSeq
+	}
+
+	itemKey := db.lEncodeListKey(key, seq)
+	value, err = db.bucket.Get(itemKey)
+	if err != nil {
+		return nil, err
+	}
+
+	if whereSeq == listHeadSeq {
+		headSeq += 1
+	} else {
+		tailSeq -= 1
+	}
+
+	t.Delete(itemKey)
+	size := db.lSetMeta(metaKey, headSeq, tailSeq)
+	if size == 0 {
+		db.rmExpire(t, HashType, key)
+	}
+
+	err = t.Commit()
+	return value, err
+}
+
+//	ps : here just focus on deleting the list data,
+//		 any other likes expire is ignore.
+func (db *DB) lDelete(t *batch, key []byte) int64 {
+	mk := db.lEncodeMetaKey(key)
+
+	var headSeq int32
+	var tailSeq int32
+	var err error
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	headSeq, tailSeq, _, err = db.lGetMeta(it, mk)
+	if err != nil {
+		return 0
+	}
+
+	var num int64 = 0
+	startKey := db.lEncodeListKey(key, headSeq)
+	stopKey := db.lEncodeListKey(key, tailSeq)
+
+	rit := store.NewRangeIterator(it, &store.Range{startKey, stopKey, store.RangeClose})
+	for ; rit.Valid(); rit.Next() {
+		t.Delete(rit.RawKey())
+		num++
+	}
+
+	t.Delete(mk)
+
+	return num
+}
+
+func (db *DB) lGetMeta(it *store.Iterator, ek []byte) (headSeq int32, tailSeq int32, size int32, err error) {
+	var v []byte
+	if it != nil {
+		v = it.Find(ek)
+	} else {
+		v, err = db.bucket.Get(ek)
+	}
+	if err != nil {
+		return
+	} else if v == nil {
+		headSeq = listInitialSeq
+		tailSeq = listInitialSeq
+		size = 0
+		return
+	} else {
+		headSeq = int32(binary.LittleEndian.Uint32(v[0:4]))
+		tailSeq = int32(binary.LittleEndian.Uint32(v[4:8]))
+		size = tailSeq - headSeq + 1
+	}
+	return
+}
+
+func (db *DB) lSetMeta(ek []byte, headSeq int32, tailSeq int32) int32 {
+	t := db.listBatch
+
+	var size int32 = tailSeq - headSeq + 1
+	if size < 0 {
+		//	todo : log error + panic
+	} else if size == 0 {
+		t.Delete(ek)
+	} else {
+		buf := make([]byte, 8)
+
+		binary.LittleEndian.PutUint32(buf[0:4], uint32(headSeq))
+		binary.LittleEndian.PutUint32(buf[4:8], uint32(tailSeq))
+
+		t.Put(ek, buf)
+	}
+
+	return size
+}
+
+func (db *DB) lExpireAt(key []byte, when int64) (int64, error) {
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+
+	if llen, err := db.LLen(key); err != nil || llen == 0 {
+		return 0, err
+	} else {
+		db.expireAt(t, ListType, key, when)
+		if err := t.Commit(); err != nil {
+			return 0, err
+		}
+	}
+	return 1, nil
+}
+
+func (db *DB) LIndex(key []byte, index int32) ([]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	var seq int32
+	var headSeq int32
+	var tailSeq int32
+	var err error
+
+	metaKey := db.lEncodeMetaKey(key)
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	headSeq, tailSeq, _, err = db.lGetMeta(it, metaKey)
+	if err != nil {
+		return nil, err
+	}
+
+	if index >= 0 {
+		seq = headSeq + index
+	} else {
+		seq = tailSeq + index + 1
+	}
+
+	sk := db.lEncodeListKey(key, seq)
+	v := it.Find(sk)
+
+	return v, nil
+}
+
+func (db *DB) LLen(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	ek := db.lEncodeMetaKey(key)
+	_, _, size, err := db.lGetMeta(nil, ek)
+	return int64(size), err
+}
+
+func (db *DB) LPop(key []byte) ([]byte, error) {
+	return db.lpop(key, listHeadSeq)
+}
+
+func (db *DB) LPush(key []byte, arg1 []byte, args ...[]byte) (int64, error) {
+	var argss = [][]byte{arg1}
+	argss = append(argss, args...)
+	return db.lpush(key, listHeadSeq, argss...)
+}
+
+func (db *DB) LRange(key []byte, start int32, stop int32) ([][]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	var headSeq int32
+	var llen int32
+	var err error
+
+	metaKey := db.lEncodeMetaKey(key)
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	if headSeq, _, llen, err = db.lGetMeta(it, metaKey); err != nil {
+		return nil, err
+	}
+
+	if start < 0 {
+		start = llen + start
+	}
+	if stop < 0 {
+		stop = llen + stop
+	}
+	if start < 0 {
+		start = 0
+	}
+
+	if start > stop || start >= llen {
+		return [][]byte{}, nil
+	}
+
+	if stop >= llen {
+		stop = llen - 1
+	}
+
+	limit := (stop - start) + 1
+	headSeq += start
+
+	v := make([][]byte, 0, limit)
+
+	startKey := db.lEncodeListKey(key, headSeq)
+	rit := store.NewRangeLimitIterator(it,
+		&store.Range{
+			Min:  startKey,
+			Max:  nil,
+			Type: store.RangeClose},
+		&store.Limit{
+			Offset: 0,
+			Count:  int(limit)})
+
+	for ; rit.Valid(); rit.Next() {
+		v = append(v, rit.Value())
+	}
+
+	return v, nil
+}
+
+func (db *DB) RPop(key []byte) ([]byte, error) {
+	return db.lpop(key, listTailSeq)
+}
+
+func (db *DB) RPush(key []byte, arg1 []byte, args ...[]byte) (int64, error) {
+	var argss = [][]byte{arg1}
+	argss = append(argss, args...)
+	return db.lpush(key, listTailSeq, argss...)
+}
+
+func (db *DB) LClear(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+
+	num := db.lDelete(t, key)
+	db.rmExpire(t, ListType, key)
+
+	err := t.Commit()
+	return num, err
+}
+
+func (db *DB) LMclear(keys ...[]byte) (int64, error) {
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+
+	for _, key := range keys {
+		if err := checkKeySize(key); err != nil {
+			return 0, err
+		}
+
+		db.lDelete(t, key)
+		db.rmExpire(t, ListType, key)
+
+	}
+
+	err := t.Commit()
+	return int64(len(keys)), err
+}
+
+func (db *DB) lFlush() (drop int64, err error) {
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+	return db.flushType(t, ListType)
+}
+
+func (db *DB) LExpire(key []byte, duration int64) (int64, error) {
+	if duration <= 0 {
+		return 0, errExpireValue
+	}
+
+	return db.lExpireAt(key, time.Now().Unix()+duration)
+}
+
+func (db *DB) LExpireAt(key []byte, when int64) (int64, error) {
+	if when <= time.Now().Unix() {
+		return 0, errExpireValue
+	}
+
+	return db.lExpireAt(key, when)
+}
+
+func (db *DB) LTTL(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.ttl(ListType, key)
+}
+
+func (db *DB) LPersist(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.listBatch
+	t.Lock()
+	defer t.Unlock()
+
+	n, err := db.rmExpire(t, ListType, key)
+	if err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return n, err
+}
+
+func (db *DB) LScan(key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	return db.scan(LMetaType, key, count, inclusive, match)
+}
+
+func (db *DB) lEncodeMinKey() []byte {
+	return db.lEncodeMetaKey(nil)
+}
+
+func (db *DB) lEncodeMaxKey() []byte {
+	ek := db.lEncodeMetaKey(nil)
+	ek[len(ek)-1] = LMetaType + 1
+	return ek
+}
diff --git a/vendor/github.com/lunny/nodb/t_set.go b/vendor/github.com/lunny/nodb/t_set.go
new file mode 100644
index 0000000000..41ce30e8ce
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_set.go
@@ -0,0 +1,601 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"time"
+
+	"github.com/lunny/nodb/store"
+)
+
+var errSetKey = errors.New("invalid set key")
+var errSSizeKey = errors.New("invalid ssize key")
+
+const (
+	setStartSep byte = ':'
+	setStopSep  byte = setStartSep + 1
+	UnionType   byte = 51
+	DiffType    byte = 52
+	InterType   byte = 53
+)
+
+func checkSetKMSize(key []byte, member []byte) error {
+	if len(key) > MaxKeySize || len(key) == 0 {
+		return errKeySize
+	} else if len(member) > MaxSetMemberSize || len(member) == 0 {
+		return errSetMemberSize
+	}
+	return nil
+}
+
+func (db *DB) sEncodeSizeKey(key []byte) []byte {
+	buf := make([]byte, len(key)+2)
+
+	buf[0] = db.index
+	buf[1] = SSizeType
+
+	copy(buf[2:], key)
+	return buf
+}
+
+func (db *DB) sDecodeSizeKey(ek []byte) ([]byte, error) {
+	if len(ek) < 2 || ek[0] != db.index || ek[1] != SSizeType {
+		return nil, errSSizeKey
+	}
+
+	return ek[2:], nil
+}
+
+func (db *DB) sEncodeSetKey(key []byte, member []byte) []byte {
+	buf := make([]byte, len(key)+len(member)+1+1+2+1)
+
+	pos := 0
+	buf[pos] = db.index
+	pos++
+	buf[pos] = SetType
+	pos++
+
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+	pos += 2
+
+	copy(buf[pos:], key)
+	pos += len(key)
+
+	buf[pos] = setStartSep
+	pos++
+	copy(buf[pos:], member)
+
+	return buf
+}
+
+func (db *DB) sDecodeSetKey(ek []byte) ([]byte, []byte, error) {
+	if len(ek) < 5 || ek[0] != db.index || ek[1] != SetType {
+		return nil, nil, errSetKey
+	}
+
+	pos := 2
+	keyLen := int(binary.BigEndian.Uint16(ek[pos:]))
+	pos += 2
+
+	if keyLen+5 > len(ek) {
+		return nil, nil, errSetKey
+	}
+
+	key := ek[pos : pos+keyLen]
+	pos += keyLen
+
+	if ek[pos] != hashStartSep {
+		return nil, nil, errSetKey
+	}
+
+	pos++
+	member := ek[pos:]
+	return key, member, nil
+}
+
+func (db *DB) sEncodeStartKey(key []byte) []byte {
+	return db.sEncodeSetKey(key, nil)
+}
+
+func (db *DB) sEncodeStopKey(key []byte) []byte {
+	k := db.sEncodeSetKey(key, nil)
+
+	k[len(k)-1] = setStopSep
+
+	return k
+}
+
+func (db *DB) sFlush() (drop int64, err error) {
+
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	return db.flushType(t, SetType)
+}
+
+func (db *DB) sDelete(t *batch, key []byte) int64 {
+	sk := db.sEncodeSizeKey(key)
+	start := db.sEncodeStartKey(key)
+	stop := db.sEncodeStopKey(key)
+
+	var num int64 = 0
+	it := db.bucket.RangeLimitIterator(start, stop, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		t.Delete(it.RawKey())
+		num++
+	}
+
+	it.Close()
+
+	t.Delete(sk)
+	return num
+}
+
+func (db *DB) sIncrSize(key []byte, delta int64) (int64, error) {
+	t := db.setBatch
+	sk := db.sEncodeSizeKey(key)
+
+	var err error
+	var size int64 = 0
+	if size, err = Int64(db.bucket.Get(sk)); err != nil {
+		return 0, err
+	} else {
+		size += delta
+		if size <= 0 {
+			size = 0
+			t.Delete(sk)
+			db.rmExpire(t, SetType, key)
+		} else {
+			t.Put(sk, PutInt64(size))
+		}
+	}
+
+	return size, nil
+}
+
+func (db *DB) sExpireAt(key []byte, when int64) (int64, error) {
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	if scnt, err := db.SCard(key); err != nil || scnt == 0 {
+		return 0, err
+	} else {
+		db.expireAt(t, SetType, key, when)
+		if err := t.Commit(); err != nil {
+			return 0, err
+		}
+
+	}
+
+	return 1, nil
+}
+
+func (db *DB) sSetItem(key []byte, member []byte) (int64, error) {
+	t := db.setBatch
+	ek := db.sEncodeSetKey(key, member)
+
+	var n int64 = 1
+	if v, _ := db.bucket.Get(ek); v != nil {
+		n = 0
+	} else {
+		if _, err := db.sIncrSize(key, 1); err != nil {
+			return 0, err
+		}
+	}
+
+	t.Put(ek, nil)
+	return n, nil
+}
+
+func (db *DB) SAdd(key []byte, args ...[]byte) (int64, error) {
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var err error
+	var ek []byte
+	var num int64 = 0
+	for i := 0; i < len(args); i++ {
+		if err := checkSetKMSize(key, args[i]); err != nil {
+			return 0, err
+		}
+
+		ek = db.sEncodeSetKey(key, args[i])
+
+		if v, err := db.bucket.Get(ek); err != nil {
+			return 0, err
+		} else if v == nil {
+			num++
+		}
+
+		t.Put(ek, nil)
+	}
+
+	if _, err = db.sIncrSize(key, num); err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return num, err
+
+}
+
+func (db *DB) SCard(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	sk := db.sEncodeSizeKey(key)
+
+	return Int64(db.bucket.Get(sk))
+}
+
+func (db *DB) sDiffGeneric(keys ...[]byte) ([][]byte, error) {
+	destMap := make(map[string]bool)
+
+	members, err := db.SMembers(keys[0])
+	if err != nil {
+		return nil, err
+	}
+
+	for _, m := range members {
+		destMap[String(m)] = true
+	}
+
+	for _, k := range keys[1:] {
+		members, err := db.SMembers(k)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, m := range members {
+			if _, ok := destMap[String(m)]; !ok {
+				continue
+			} else if ok {
+				delete(destMap, String(m))
+			}
+		}
+		// O - A = O, O is zero set.
+		if len(destMap) == 0 {
+			return nil, nil
+		}
+	}
+
+	slice := make([][]byte, len(destMap))
+	idx := 0
+	for k, v := range destMap {
+		if !v {
+			continue
+		}
+		slice[idx] = []byte(k)
+		idx++
+	}
+
+	return slice, nil
+}
+
+func (db *DB) SDiff(keys ...[]byte) ([][]byte, error) {
+	v, err := db.sDiffGeneric(keys...)
+	return v, err
+}
+
+func (db *DB) SDiffStore(dstKey []byte, keys ...[]byte) (int64, error) {
+	n, err := db.sStoreGeneric(dstKey, DiffType, keys...)
+	return n, err
+}
+
+func (db *DB) sInterGeneric(keys ...[]byte) ([][]byte, error) {
+	destMap := make(map[string]bool)
+
+	members, err := db.SMembers(keys[0])
+	if err != nil {
+		return nil, err
+	}
+
+	for _, m := range members {
+		destMap[String(m)] = true
+	}
+
+	for _, key := range keys[1:] {
+		if err := checkKeySize(key); err != nil {
+			return nil, err
+		}
+
+		members, err := db.SMembers(key)
+		if err != nil {
+			return nil, err
+		} else if len(members) == 0 {
+			return nil, err
+		}
+
+		tempMap := make(map[string]bool)
+		for _, member := range members {
+			if err := checkKeySize(member); err != nil {
+				return nil, err
+			}
+			if _, ok := destMap[String(member)]; ok {
+				tempMap[String(member)] = true //mark this item as selected
+			}
+		}
+		destMap = tempMap //reduce the size of the result set
+		if len(destMap) == 0 {
+			return nil, nil
+		}
+	}
+
+	slice := make([][]byte, len(destMap))
+	idx := 0
+	for k, v := range destMap {
+		if !v {
+			continue
+		}
+
+		slice[idx] = []byte(k)
+		idx++
+	}
+
+	return slice, nil
+
+}
+
+func (db *DB) SInter(keys ...[]byte) ([][]byte, error) {
+	v, err := db.sInterGeneric(keys...)
+	return v, err
+
+}
+
+func (db *DB) SInterStore(dstKey []byte, keys ...[]byte) (int64, error) {
+	n, err := db.sStoreGeneric(dstKey, InterType, keys...)
+	return n, err
+}
+
+func (db *DB) SIsMember(key []byte, member []byte) (int64, error) {
+	ek := db.sEncodeSetKey(key, member)
+
+	var n int64 = 1
+	if v, err := db.bucket.Get(ek); err != nil {
+		return 0, err
+	} else if v == nil {
+		n = 0
+	}
+	return n, nil
+}
+
+func (db *DB) SMembers(key []byte) ([][]byte, error) {
+	if err := checkKeySize(key); err != nil {
+		return nil, err
+	}
+
+	start := db.sEncodeStartKey(key)
+	stop := db.sEncodeStopKey(key)
+
+	v := make([][]byte, 0, 16)
+
+	it := db.bucket.RangeLimitIterator(start, stop, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		_, m, err := db.sDecodeSetKey(it.Key())
+		if err != nil {
+			return nil, err
+		}
+
+		v = append(v, m)
+	}
+
+	it.Close()
+
+	return v, nil
+}
+
+func (db *DB) SRem(key []byte, args ...[]byte) (int64, error) {
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var ek []byte
+	var v []byte
+	var err error
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	var num int64 = 0
+	for i := 0; i < len(args); i++ {
+		if err := checkSetKMSize(key, args[i]); err != nil {
+			return 0, err
+		}
+
+		ek = db.sEncodeSetKey(key, args[i])
+
+		v = it.RawFind(ek)
+		if v == nil {
+			continue
+		} else {
+			num++
+			t.Delete(ek)
+		}
+	}
+
+	if _, err = db.sIncrSize(key, -num); err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return num, err
+
+}
+
+func (db *DB) sUnionGeneric(keys ...[]byte) ([][]byte, error) {
+	dstMap := make(map[string]bool)
+
+	for _, key := range keys {
+		if err := checkKeySize(key); err != nil {
+			return nil, err
+		}
+
+		members, err := db.SMembers(key)
+		if err != nil {
+			return nil, err
+		}
+
+		for _, member := range members {
+			dstMap[String(member)] = true
+		}
+	}
+
+	slice := make([][]byte, len(dstMap))
+	idx := 0
+	for k, v := range dstMap {
+		if !v {
+			continue
+		}
+		slice[idx] = []byte(k)
+		idx++
+	}
+
+	return slice, nil
+}
+
+func (db *DB) SUnion(keys ...[]byte) ([][]byte, error) {
+	v, err := db.sUnionGeneric(keys...)
+	return v, err
+}
+
+func (db *DB) SUnionStore(dstKey []byte, keys ...[]byte) (int64, error) {
+	n, err := db.sStoreGeneric(dstKey, UnionType, keys...)
+	return n, err
+}
+
+func (db *DB) sStoreGeneric(dstKey []byte, optType byte, keys ...[]byte) (int64, error) {
+	if err := checkKeySize(dstKey); err != nil {
+		return 0, err
+	}
+
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	db.sDelete(t, dstKey)
+
+	var err error
+	var ek []byte
+	var v [][]byte
+
+	switch optType {
+	case UnionType:
+		v, err = db.sUnionGeneric(keys...)
+	case DiffType:
+		v, err = db.sDiffGeneric(keys...)
+	case InterType:
+		v, err = db.sInterGeneric(keys...)
+	}
+
+	if err != nil {
+		return 0, err
+	}
+
+	for _, m := range v {
+		if err := checkSetKMSize(dstKey, m); err != nil {
+			return 0, err
+		}
+
+		ek = db.sEncodeSetKey(dstKey, m)
+
+		if _, err := db.bucket.Get(ek); err != nil {
+			return 0, err
+		}
+
+		t.Put(ek, nil)
+	}
+
+	var num = int64(len(v))
+	sk := db.sEncodeSizeKey(dstKey)
+	t.Put(sk, PutInt64(num))
+
+	if err = t.Commit(); err != nil {
+		return 0, err
+	}
+	return num, nil
+}
+
+func (db *DB) SClear(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	num := db.sDelete(t, key)
+	db.rmExpire(t, SetType, key)
+
+	err := t.Commit()
+	return num, err
+}
+
+func (db *DB) SMclear(keys ...[]byte) (int64, error) {
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	for _, key := range keys {
+		if err := checkKeySize(key); err != nil {
+			return 0, err
+		}
+
+		db.sDelete(t, key)
+		db.rmExpire(t, SetType, key)
+	}
+
+	err := t.Commit()
+	return int64(len(keys)), err
+}
+
+func (db *DB) SExpire(key []byte, duration int64) (int64, error) {
+	if duration <= 0 {
+		return 0, errExpireValue
+	}
+
+	return db.sExpireAt(key, time.Now().Unix()+duration)
+
+}
+
+func (db *DB) SExpireAt(key []byte, when int64) (int64, error) {
+	if when <= time.Now().Unix() {
+		return 0, errExpireValue
+	}
+
+	return db.sExpireAt(key, when)
+
+}
+
+func (db *DB) STTL(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.ttl(SetType, key)
+}
+
+func (db *DB) SPersist(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.setBatch
+	t.Lock()
+	defer t.Unlock()
+
+	n, err := db.rmExpire(t, SetType, key)
+	if err != nil {
+		return 0, err
+	}
+	err = t.Commit()
+	return n, err
+}
+
+func (db *DB) SScan(key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	return db.scan(SSizeType, key, count, inclusive, match)
+}
diff --git a/vendor/github.com/lunny/nodb/t_ttl.go b/vendor/github.com/lunny/nodb/t_ttl.go
new file mode 100644
index 0000000000..5c3638891c
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_ttl.go
@@ -0,0 +1,195 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"time"
+
+	"github.com/lunny/nodb/store"
+)
+
+var (
+	errExpMetaKey = errors.New("invalid expire meta key")
+	errExpTimeKey = errors.New("invalid expire time key")
+)
+
+type retireCallback func(*batch, []byte) int64
+
+type elimination struct {
+	db         *DB
+	exp2Tx     []*batch
+	exp2Retire []retireCallback
+}
+
+var errExpType = errors.New("invalid expire type")
+
+func (db *DB) expEncodeTimeKey(dataType byte, key []byte, when int64) []byte {
+	buf := make([]byte, len(key)+11)
+
+	buf[0] = db.index
+	buf[1] = ExpTimeType
+	buf[2] = dataType
+	pos := 3
+
+	binary.BigEndian.PutUint64(buf[pos:], uint64(when))
+	pos += 8
+
+	copy(buf[pos:], key)
+
+	return buf
+}
+
+func (db *DB) expEncodeMetaKey(dataType byte, key []byte) []byte {
+	buf := make([]byte, len(key)+3)
+
+	buf[0] = db.index
+	buf[1] = ExpMetaType
+	buf[2] = dataType
+	pos := 3
+
+	copy(buf[pos:], key)
+
+	return buf
+}
+
+func (db *DB) expDecodeMetaKey(mk []byte) (byte, []byte, error) {
+	if len(mk) <= 3 || mk[0] != db.index || mk[1] != ExpMetaType {
+		return 0, nil, errExpMetaKey
+	}
+
+	return mk[2], mk[3:], nil
+}
+
+func (db *DB) expDecodeTimeKey(tk []byte) (byte, []byte, int64, error) {
+	if len(tk) < 11 || tk[0] != db.index || tk[1] != ExpTimeType {
+		return 0, nil, 0, errExpTimeKey
+	}
+
+	return tk[2], tk[11:], int64(binary.BigEndian.Uint64(tk[3:])), nil
+}
+
+func (db *DB) expire(t *batch, dataType byte, key []byte, duration int64) {
+	db.expireAt(t, dataType, key, time.Now().Unix()+duration)
+}
+
+func (db *DB) expireAt(t *batch, dataType byte, key []byte, when int64) {
+	mk := db.expEncodeMetaKey(dataType, key)
+	tk := db.expEncodeTimeKey(dataType, key, when)
+
+	t.Put(tk, mk)
+	t.Put(mk, PutInt64(when))
+}
+
+func (db *DB) ttl(dataType byte, key []byte) (t int64, err error) {
+	mk := db.expEncodeMetaKey(dataType, key)
+
+	if t, err = Int64(db.bucket.Get(mk)); err != nil || t == 0 {
+		t = -1
+	} else {
+		t -= time.Now().Unix()
+		if t <= 0 {
+			t = -1
+		}
+		// if t == -1 : to remove ????
+	}
+
+	return t, err
+}
+
+func (db *DB) rmExpire(t *batch, dataType byte, key []byte) (int64, error) {
+	mk := db.expEncodeMetaKey(dataType, key)
+	if v, err := db.bucket.Get(mk); err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else if when, err2 := Int64(v, nil); err2 != nil {
+		return 0, err2
+	} else {
+		tk := db.expEncodeTimeKey(dataType, key, when)
+		t.Delete(mk)
+		t.Delete(tk)
+		return 1, nil
+	}
+}
+
+func (db *DB) expFlush(t *batch, dataType byte) (err error) {
+	minKey := make([]byte, 3)
+	minKey[0] = db.index
+	minKey[1] = ExpTimeType
+	minKey[2] = dataType
+
+	maxKey := make([]byte, 3)
+	maxKey[0] = db.index
+	maxKey[1] = ExpMetaType
+	maxKey[2] = dataType + 1
+
+	_, err = db.flushRegion(t, minKey, maxKey)
+	err = t.Commit()
+	return
+}
+
+//////////////////////////////////////////////////////////
+//
+//////////////////////////////////////////////////////////
+
+func newEliminator(db *DB) *elimination {
+	eli := new(elimination)
+	eli.db = db
+	eli.exp2Tx = make([]*batch, maxDataType)
+	eli.exp2Retire = make([]retireCallback, maxDataType)
+	return eli
+}
+
+func (eli *elimination) regRetireContext(dataType byte, t *batch, onRetire retireCallback) {
+
+	//	todo .. need to ensure exist - mapExpMetaType[expType]
+
+	eli.exp2Tx[dataType] = t
+	eli.exp2Retire[dataType] = onRetire
+}
+
+//	call by outside ... (from *db to another *db)
+func (eli *elimination) active() {
+	now := time.Now().Unix()
+	db := eli.db
+	dbGet := db.bucket.Get
+
+	minKey := db.expEncodeTimeKey(NoneType, nil, 0)
+	maxKey := db.expEncodeTimeKey(maxDataType, nil, now)
+
+	it := db.bucket.RangeLimitIterator(minKey, maxKey, store.RangeROpen, 0, -1)
+	for ; it.Valid(); it.Next() {
+		tk := it.RawKey()
+		mk := it.RawValue()
+
+		dt, k, _, err := db.expDecodeTimeKey(tk)
+		if err != nil {
+			continue
+		}
+
+		t := eli.exp2Tx[dt]
+		onRetire := eli.exp2Retire[dt]
+		if tk == nil || onRetire == nil {
+			continue
+		}
+
+		t.Lock()
+
+		if exp, err := Int64(dbGet(mk)); err == nil {
+			// check expire again
+			if exp <= now {
+				onRetire(t, k)
+				t.Delete(tk)
+				t.Delete(mk)
+
+				t.Commit()
+			}
+
+		}
+
+		t.Unlock()
+	}
+	it.Close()
+
+	return
+}
diff --git a/vendor/github.com/lunny/nodb/t_zset.go b/vendor/github.com/lunny/nodb/t_zset.go
new file mode 100644
index 0000000000..d0ffb7ccf3
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/t_zset.go
@@ -0,0 +1,943 @@
+package nodb
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"time"
+
+	"github.com/lunny/nodb/store"
+)
+
+const (
+	MinScore     int64 = -1<<63 + 1
+	MaxScore     int64 = 1<<63 - 1
+	InvalidScore int64 = -1 << 63
+
+	AggregateSum byte = 0
+	AggregateMin byte = 1
+	AggregateMax byte = 2
+)
+
+type ScorePair struct {
+	Score  int64
+	Member []byte
+}
+
+var errZSizeKey = errors.New("invalid zsize key")
+var errZSetKey = errors.New("invalid zset key")
+var errZScoreKey = errors.New("invalid zscore key")
+var errScoreOverflow = errors.New("zset score overflow")
+var errInvalidAggregate = errors.New("invalid aggregate")
+var errInvalidWeightNum = errors.New("invalid weight number")
+var errInvalidSrcKeyNum = errors.New("invalid src key number")
+
+const (
+	zsetNScoreSep    byte = '<'
+	zsetPScoreSep    byte = zsetNScoreSep + 1
+	zsetStopScoreSep byte = zsetPScoreSep + 1
+
+	zsetStartMemSep byte = ':'
+	zsetStopMemSep  byte = zsetStartMemSep + 1
+)
+
+func checkZSetKMSize(key []byte, member []byte) error {
+	if len(key) > MaxKeySize || len(key) == 0 {
+		return errKeySize
+	} else if len(member) > MaxZSetMemberSize || len(member) == 0 {
+		return errZSetMemberSize
+	}
+	return nil
+}
+
+func (db *DB) zEncodeSizeKey(key []byte) []byte {
+	buf := make([]byte, len(key)+2)
+	buf[0] = db.index
+	buf[1] = ZSizeType
+
+	copy(buf[2:], key)
+	return buf
+}
+
+func (db *DB) zDecodeSizeKey(ek []byte) ([]byte, error) {
+	if len(ek) < 2 || ek[0] != db.index || ek[1] != ZSizeType {
+		return nil, errZSizeKey
+	}
+
+	return ek[2:], nil
+}
+
+func (db *DB) zEncodeSetKey(key []byte, member []byte) []byte {
+	buf := make([]byte, len(key)+len(member)+5)
+
+	pos := 0
+	buf[pos] = db.index
+	pos++
+
+	buf[pos] = ZSetType
+	pos++
+
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+	pos += 2
+
+	copy(buf[pos:], key)
+	pos += len(key)
+
+	buf[pos] = zsetStartMemSep
+	pos++
+
+	copy(buf[pos:], member)
+
+	return buf
+}
+
+func (db *DB) zDecodeSetKey(ek []byte) ([]byte, []byte, error) {
+	if len(ek) < 5 || ek[0] != db.index || ek[1] != ZSetType {
+		return nil, nil, errZSetKey
+	}
+
+	keyLen := int(binary.BigEndian.Uint16(ek[2:]))
+	if keyLen+5 > len(ek) {
+		return nil, nil, errZSetKey
+	}
+
+	key := ek[4 : 4+keyLen]
+
+	if ek[4+keyLen] != zsetStartMemSep {
+		return nil, nil, errZSetKey
+	}
+
+	member := ek[5+keyLen:]
+	return key, member, nil
+}
+
+func (db *DB) zEncodeStartSetKey(key []byte) []byte {
+	k := db.zEncodeSetKey(key, nil)
+	return k
+}
+
+func (db *DB) zEncodeStopSetKey(key []byte) []byte {
+	k := db.zEncodeSetKey(key, nil)
+	k[len(k)-1] = zsetStartMemSep + 1
+	return k
+}
+
+func (db *DB) zEncodeScoreKey(key []byte, member []byte, score int64) []byte {
+	buf := make([]byte, len(key)+len(member)+14)
+
+	pos := 0
+	buf[pos] = db.index
+	pos++
+
+	buf[pos] = ZScoreType
+	pos++
+
+	binary.BigEndian.PutUint16(buf[pos:], uint16(len(key)))
+	pos += 2
+
+	copy(buf[pos:], key)
+	pos += len(key)
+
+	if score < 0 {
+		buf[pos] = zsetNScoreSep
+	} else {
+		buf[pos] = zsetPScoreSep
+	}
+
+	pos++
+	binary.BigEndian.PutUint64(buf[pos:], uint64(score))
+	pos += 8
+
+	buf[pos] = zsetStartMemSep
+	pos++
+
+	copy(buf[pos:], member)
+	return buf
+}
+
+func (db *DB) zEncodeStartScoreKey(key []byte, score int64) []byte {
+	return db.zEncodeScoreKey(key, nil, score)
+}
+
+func (db *DB) zEncodeStopScoreKey(key []byte, score int64) []byte {
+	k := db.zEncodeScoreKey(key, nil, score)
+	k[len(k)-1] = zsetStopMemSep
+	return k
+}
+
+func (db *DB) zDecodeScoreKey(ek []byte) (key []byte, member []byte, score int64, err error) {
+	if len(ek) < 14 || ek[0] != db.index || ek[1] != ZScoreType {
+		err = errZScoreKey
+		return
+	}
+
+	keyLen := int(binary.BigEndian.Uint16(ek[2:]))
+	if keyLen+14 > len(ek) {
+		err = errZScoreKey
+		return
+	}
+
+	key = ek[4 : 4+keyLen]
+	pos := 4 + keyLen
+
+	if (ek[pos] != zsetNScoreSep) && (ek[pos] != zsetPScoreSep) {
+		err = errZScoreKey
+		return
+	}
+	pos++
+
+	score = int64(binary.BigEndian.Uint64(ek[pos:]))
+	pos += 8
+
+	if ek[pos] != zsetStartMemSep {
+		err = errZScoreKey
+		return
+	}
+
+	pos++
+
+	member = ek[pos:]
+	return
+}
+
+func (db *DB) zSetItem(t *batch, key []byte, score int64, member []byte) (int64, error) {
+	if score <= MinScore || score >= MaxScore {
+		return 0, errScoreOverflow
+	}
+
+	var exists int64 = 0
+	ek := db.zEncodeSetKey(key, member)
+
+	if v, err := db.bucket.Get(ek); err != nil {
+		return 0, err
+	} else if v != nil {
+		exists = 1
+
+		if s, err := Int64(v, err); err != nil {
+			return 0, err
+		} else {
+			sk := db.zEncodeScoreKey(key, member, s)
+			t.Delete(sk)
+		}
+	}
+
+	t.Put(ek, PutInt64(score))
+
+	sk := db.zEncodeScoreKey(key, member, score)
+	t.Put(sk, []byte{})
+
+	return exists, nil
+}
+
+func (db *DB) zDelItem(t *batch, key []byte, member []byte, skipDelScore bool) (int64, error) {
+	ek := db.zEncodeSetKey(key, member)
+	if v, err := db.bucket.Get(ek); err != nil {
+		return 0, err
+	} else if v == nil {
+		//not exists
+		return 0, nil
+	} else {
+		//exists
+		if !skipDelScore {
+			//we must del score
+			if s, err := Int64(v, err); err != nil {
+				return 0, err
+			} else {
+				sk := db.zEncodeScoreKey(key, member, s)
+				t.Delete(sk)
+			}
+		}
+	}
+
+	t.Delete(ek)
+
+	return 1, nil
+}
+
+func (db *DB) zDelete(t *batch, key []byte) int64 {
+	delMembCnt, _ := db.zRemRange(t, key, MinScore, MaxScore, 0, -1)
+	//	todo : log err
+	return delMembCnt
+}
+
+func (db *DB) zExpireAt(key []byte, when int64) (int64, error) {
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	if zcnt, err := db.ZCard(key); err != nil || zcnt == 0 {
+		return 0, err
+	} else {
+		db.expireAt(t, ZSetType, key, when)
+		if err := t.Commit(); err != nil {
+			return 0, err
+		}
+	}
+	return 1, nil
+}
+
+func (db *DB) ZAdd(key []byte, args ...ScorePair) (int64, error) {
+	if len(args) == 0 {
+		return 0, nil
+	}
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var num int64 = 0
+	for i := 0; i < len(args); i++ {
+		score := args[i].Score
+		member := args[i].Member
+
+		if err := checkZSetKMSize(key, member); err != nil {
+			return 0, err
+		}
+
+		if n, err := db.zSetItem(t, key, score, member); err != nil {
+			return 0, err
+		} else if n == 0 {
+			//add new
+			num++
+		}
+	}
+
+	if _, err := db.zIncrSize(t, key, num); err != nil {
+		return 0, err
+	}
+
+	//todo add binlog
+	err := t.Commit()
+	return num, err
+}
+
+func (db *DB) zIncrSize(t *batch, key []byte, delta int64) (int64, error) {
+	sk := db.zEncodeSizeKey(key)
+
+	size, err := Int64(db.bucket.Get(sk))
+	if err != nil {
+		return 0, err
+	} else {
+		size += delta
+		if size <= 0 {
+			size = 0
+			t.Delete(sk)
+			db.rmExpire(t, ZSetType, key)
+		} else {
+			t.Put(sk, PutInt64(size))
+		}
+	}
+
+	return size, nil
+}
+
+func (db *DB) ZCard(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	sk := db.zEncodeSizeKey(key)
+	return Int64(db.bucket.Get(sk))
+}
+
+func (db *DB) ZScore(key []byte, member []byte) (int64, error) {
+	if err := checkZSetKMSize(key, member); err != nil {
+		return InvalidScore, err
+	}
+
+	var score int64 = InvalidScore
+
+	k := db.zEncodeSetKey(key, member)
+	if v, err := db.bucket.Get(k); err != nil {
+		return InvalidScore, err
+	} else if v == nil {
+		return InvalidScore, ErrScoreMiss
+	} else {
+		if score, err = Int64(v, nil); err != nil {
+			return InvalidScore, err
+		}
+	}
+
+	return score, nil
+}
+
+func (db *DB) ZRem(key []byte, members ...[]byte) (int64, error) {
+	if len(members) == 0 {
+		return 0, nil
+	}
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	var num int64 = 0
+	for i := 0; i < len(members); i++ {
+		if err := checkZSetKMSize(key, members[i]); err != nil {
+			return 0, err
+		}
+
+		if n, err := db.zDelItem(t, key, members[i], false); err != nil {
+			return 0, err
+		} else if n == 1 {
+			num++
+		}
+	}
+
+	if _, err := db.zIncrSize(t, key, -num); err != nil {
+		return 0, err
+	}
+
+	err := t.Commit()
+	return num, err
+}
+
+func (db *DB) ZIncrBy(key []byte, delta int64, member []byte) (int64, error) {
+	if err := checkZSetKMSize(key, member); err != nil {
+		return InvalidScore, err
+	}
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	ek := db.zEncodeSetKey(key, member)
+
+	var oldScore int64 = 0
+	v, err := db.bucket.Get(ek)
+	if err != nil {
+		return InvalidScore, err
+	} else if v == nil {
+		db.zIncrSize(t, key, 1)
+	} else {
+		if oldScore, err = Int64(v, err); err != nil {
+			return InvalidScore, err
+		}
+	}
+
+	newScore := oldScore + delta
+	if newScore >= MaxScore || newScore <= MinScore {
+		return InvalidScore, errScoreOverflow
+	}
+
+	sk := db.zEncodeScoreKey(key, member, newScore)
+	t.Put(sk, []byte{})
+	t.Put(ek, PutInt64(newScore))
+
+	if v != nil {
+		// so as to update score, we must delete the old one
+		oldSk := db.zEncodeScoreKey(key, member, oldScore)
+		t.Delete(oldSk)
+	}
+
+	err = t.Commit()
+	return newScore, err
+}
+
+func (db *DB) ZCount(key []byte, min int64, max int64) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+	minKey := db.zEncodeStartScoreKey(key, min)
+	maxKey := db.zEncodeStopScoreKey(key, max)
+
+	rangeType := store.RangeROpen
+
+	it := db.bucket.RangeLimitIterator(minKey, maxKey, rangeType, 0, -1)
+	var n int64 = 0
+	for ; it.Valid(); it.Next() {
+		n++
+	}
+	it.Close()
+
+	return n, nil
+}
+
+func (db *DB) zrank(key []byte, member []byte, reverse bool) (int64, error) {
+	if err := checkZSetKMSize(key, member); err != nil {
+		return 0, err
+	}
+
+	k := db.zEncodeSetKey(key, member)
+
+	it := db.bucket.NewIterator()
+	defer it.Close()
+
+	if v := it.Find(k); v == nil {
+		return -1, nil
+	} else {
+		if s, err := Int64(v, nil); err != nil {
+			return 0, err
+		} else {
+			var rit *store.RangeLimitIterator
+
+			sk := db.zEncodeScoreKey(key, member, s)
+
+			if !reverse {
+				minKey := db.zEncodeStartScoreKey(key, MinScore)
+
+				rit = store.NewRangeIterator(it, &store.Range{minKey, sk, store.RangeClose})
+			} else {
+				maxKey := db.zEncodeStopScoreKey(key, MaxScore)
+				rit = store.NewRevRangeIterator(it, &store.Range{sk, maxKey, store.RangeClose})
+			}
+
+			var lastKey []byte = nil
+			var n int64 = 0
+
+			for ; rit.Valid(); rit.Next() {
+				n++
+
+				lastKey = rit.BufKey(lastKey)
+			}
+
+			if _, m, _, err := db.zDecodeScoreKey(lastKey); err == nil && bytes.Equal(m, member) {
+				n--
+				return n, nil
+			}
+		}
+	}
+
+	return -1, nil
+}
+
+func (db *DB) zIterator(key []byte, min int64, max int64, offset int, count int, reverse bool) *store.RangeLimitIterator {
+	minKey := db.zEncodeStartScoreKey(key, min)
+	maxKey := db.zEncodeStopScoreKey(key, max)
+
+	if !reverse {
+		return db.bucket.RangeLimitIterator(minKey, maxKey, store.RangeClose, offset, count)
+	} else {
+		return db.bucket.RevRangeLimitIterator(minKey, maxKey, store.RangeClose, offset, count)
+	}
+}
+
+func (db *DB) zRemRange(t *batch, key []byte, min int64, max int64, offset int, count int) (int64, error) {
+	if len(key) > MaxKeySize {
+		return 0, errKeySize
+	}
+
+	it := db.zIterator(key, min, max, offset, count, false)
+	var num int64 = 0
+	for ; it.Valid(); it.Next() {
+		sk := it.RawKey()
+		_, m, _, err := db.zDecodeScoreKey(sk)
+		if err != nil {
+			continue
+		}
+
+		if n, err := db.zDelItem(t, key, m, true); err != nil {
+			return 0, err
+		} else if n == 1 {
+			num++
+		}
+
+		t.Delete(sk)
+	}
+	it.Close()
+
+	if _, err := db.zIncrSize(t, key, -num); err != nil {
+		return 0, err
+	}
+
+	return num, nil
+}
+
+func (db *DB) zRange(key []byte, min int64, max int64, offset int, count int, reverse bool) ([]ScorePair, error) {
+	if len(key) > MaxKeySize {
+		return nil, errKeySize
+	}
+
+	if offset < 0 {
+		return []ScorePair{}, nil
+	}
+
+	nv := 64
+	if count > 0 {
+		nv = count
+	}
+
+	v := make([]ScorePair, 0, nv)
+
+	var it *store.RangeLimitIterator
+
+	//if reverse and offset is 0, count < 0, we may use forward iterator then reverse
+	//because store iterator prev is slower than next
+	if !reverse || (offset == 0 && count < 0) {
+		it = db.zIterator(key, min, max, offset, count, false)
+	} else {
+		it = db.zIterator(key, min, max, offset, count, true)
+	}
+
+	for ; it.Valid(); it.Next() {
+		_, m, s, err := db.zDecodeScoreKey(it.Key())
+		//may be we will check key equal?
+		if err != nil {
+			continue
+		}
+
+		v = append(v, ScorePair{Member: m, Score: s})
+	}
+	it.Close()
+
+	if reverse && (offset == 0 && count < 0) {
+		for i, j := 0, len(v)-1; i < j; i, j = i+1, j-1 {
+			v[i], v[j] = v[j], v[i]
+		}
+	}
+
+	return v, nil
+}
+
+func (db *DB) zParseLimit(key []byte, start int, stop int) (offset int, count int, err error) {
+	if start < 0 || stop < 0 {
+		//refer redis implementation
+		var size int64
+		size, err = db.ZCard(key)
+		if err != nil {
+			return
+		}
+
+		llen := int(size)
+
+		if start < 0 {
+			start = llen + start
+		}
+		if stop < 0 {
+			stop = llen + stop
+		}
+
+		if start < 0 {
+			start = 0
+		}
+
+		if start >= llen {
+			offset = -1
+			return
+		}
+	}
+
+	if start > stop {
+		offset = -1
+		return
+	}
+
+	offset = start
+	count = (stop - start) + 1
+	return
+}
+
+func (db *DB) ZClear(key []byte) (int64, error) {
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	rmCnt, err := db.zRemRange(t, key, MinScore, MaxScore, 0, -1)
+	if err == nil {
+		err = t.Commit()
+	}
+
+	return rmCnt, err
+}
+
+func (db *DB) ZMclear(keys ...[]byte) (int64, error) {
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	for _, key := range keys {
+		if _, err := db.zRemRange(t, key, MinScore, MaxScore, 0, -1); err != nil {
+			return 0, err
+		}
+	}
+
+	err := t.Commit()
+
+	return int64(len(keys)), err
+}
+
+func (db *DB) ZRange(key []byte, start int, stop int) ([]ScorePair, error) {
+	return db.ZRangeGeneric(key, start, stop, false)
+}
+
+//min and max must be inclusive
+//if no limit, set offset = 0 and count = -1
+func (db *DB) ZRangeByScore(key []byte, min int64, max int64,
+	offset int, count int) ([]ScorePair, error) {
+	return db.ZRangeByScoreGeneric(key, min, max, offset, count, false)
+}
+
+func (db *DB) ZRank(key []byte, member []byte) (int64, error) {
+	return db.zrank(key, member, false)
+}
+
+func (db *DB) ZRemRangeByRank(key []byte, start int, stop int) (int64, error) {
+	offset, count, err := db.zParseLimit(key, start, stop)
+	if err != nil {
+		return 0, err
+	}
+
+	var rmCnt int64
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	rmCnt, err = db.zRemRange(t, key, MinScore, MaxScore, offset, count)
+	if err == nil {
+		err = t.Commit()
+	}
+
+	return rmCnt, err
+}
+
+//min and max must be inclusive
+func (db *DB) ZRemRangeByScore(key []byte, min int64, max int64) (int64, error) {
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	rmCnt, err := db.zRemRange(t, key, min, max, 0, -1)
+	if err == nil {
+		err = t.Commit()
+	}
+
+	return rmCnt, err
+}
+
+func (db *DB) ZRevRange(key []byte, start int, stop int) ([]ScorePair, error) {
+	return db.ZRangeGeneric(key, start, stop, true)
+}
+
+func (db *DB) ZRevRank(key []byte, member []byte) (int64, error) {
+	return db.zrank(key, member, true)
+}
+
+//min and max must be inclusive
+//if no limit, set offset = 0 and count = -1
+func (db *DB) ZRevRangeByScore(key []byte, min int64, max int64, offset int, count int) ([]ScorePair, error) {
+	return db.ZRangeByScoreGeneric(key, min, max, offset, count, true)
+}
+
+func (db *DB) ZRangeGeneric(key []byte, start int, stop int, reverse bool) ([]ScorePair, error) {
+	offset, count, err := db.zParseLimit(key, start, stop)
+	if err != nil {
+		return nil, err
+	}
+
+	return db.zRange(key, MinScore, MaxScore, offset, count, reverse)
+}
+
+//min and max must be inclusive
+//if no limit, set offset = 0 and count = -1
+func (db *DB) ZRangeByScoreGeneric(key []byte, min int64, max int64,
+	offset int, count int, reverse bool) ([]ScorePair, error) {
+
+	return db.zRange(key, min, max, offset, count, reverse)
+}
+
+func (db *DB) zFlush() (drop int64, err error) {
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+	return db.flushType(t, ZSetType)
+}
+
+func (db *DB) ZExpire(key []byte, duration int64) (int64, error) {
+	if duration <= 0 {
+		return 0, errExpireValue
+	}
+
+	return db.zExpireAt(key, time.Now().Unix()+duration)
+}
+
+func (db *DB) ZExpireAt(key []byte, when int64) (int64, error) {
+	if when <= time.Now().Unix() {
+		return 0, errExpireValue
+	}
+
+	return db.zExpireAt(key, when)
+}
+
+func (db *DB) ZTTL(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return -1, err
+	}
+
+	return db.ttl(ZSetType, key)
+}
+
+func (db *DB) ZPersist(key []byte) (int64, error) {
+	if err := checkKeySize(key); err != nil {
+		return 0, err
+	}
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	n, err := db.rmExpire(t, ZSetType, key)
+	if err != nil {
+		return 0, err
+	}
+
+	err = t.Commit()
+	return n, err
+}
+
+func getAggregateFunc(aggregate byte) func(int64, int64) int64 {
+	switch aggregate {
+	case AggregateSum:
+		return func(a int64, b int64) int64 {
+			return a + b
+		}
+	case AggregateMax:
+		return func(a int64, b int64) int64 {
+			if a > b {
+				return a
+			}
+			return b
+		}
+	case AggregateMin:
+		return func(a int64, b int64) int64 {
+			if a > b {
+				return b
+			}
+			return a
+		}
+	}
+	return nil
+}
+
+func (db *DB) ZUnionStore(destKey []byte, srcKeys [][]byte, weights []int64, aggregate byte) (int64, error) {
+
+	var destMap = map[string]int64{}
+	aggregateFunc := getAggregateFunc(aggregate)
+	if aggregateFunc == nil {
+		return 0, errInvalidAggregate
+	}
+	if len(srcKeys) < 1 {
+		return 0, errInvalidSrcKeyNum
+	}
+	if weights != nil {
+		if len(srcKeys) != len(weights) {
+			return 0, errInvalidWeightNum
+		}
+	} else {
+		weights = make([]int64, len(srcKeys))
+		for i := 0; i < len(weights); i++ {
+			weights[i] = 1
+		}
+	}
+
+	for i, key := range srcKeys {
+		scorePairs, err := db.ZRange(key, 0, -1)
+		if err != nil {
+			return 0, err
+		}
+		for _, pair := range scorePairs {
+			if score, ok := destMap[String(pair.Member)]; !ok {
+				destMap[String(pair.Member)] = pair.Score * weights[i]
+			} else {
+				destMap[String(pair.Member)] = aggregateFunc(score, pair.Score*weights[i])
+			}
+		}
+	}
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	db.zDelete(t, destKey)
+
+	for member, score := range destMap {
+		if err := checkZSetKMSize(destKey, []byte(member)); err != nil {
+			return 0, err
+		}
+
+		if _, err := db.zSetItem(t, destKey, score, []byte(member)); err != nil {
+			return 0, err
+		}
+	}
+
+	var num = int64(len(destMap))
+	sk := db.zEncodeSizeKey(destKey)
+	t.Put(sk, PutInt64(num))
+
+	//todo add binlog
+	if err := t.Commit(); err != nil {
+		return 0, err
+	}
+	return num, nil
+}
+
+func (db *DB) ZInterStore(destKey []byte, srcKeys [][]byte, weights []int64, aggregate byte) (int64, error) {
+
+	aggregateFunc := getAggregateFunc(aggregate)
+	if aggregateFunc == nil {
+		return 0, errInvalidAggregate
+	}
+	if len(srcKeys) < 1 {
+		return 0, errInvalidSrcKeyNum
+	}
+	if weights != nil {
+		if len(srcKeys) != len(weights) {
+			return 0, errInvalidWeightNum
+		}
+	} else {
+		weights = make([]int64, len(srcKeys))
+		for i := 0; i < len(weights); i++ {
+			weights[i] = 1
+		}
+	}
+
+	var destMap = map[string]int64{}
+	scorePairs, err := db.ZRange(srcKeys[0], 0, -1)
+	if err != nil {
+		return 0, err
+	}
+	for _, pair := range scorePairs {
+		destMap[String(pair.Member)] = pair.Score * weights[0]
+	}
+
+	for i, key := range srcKeys[1:] {
+		scorePairs, err := db.ZRange(key, 0, -1)
+		if err != nil {
+			return 0, err
+		}
+		tmpMap := map[string]int64{}
+		for _, pair := range scorePairs {
+			if score, ok := destMap[String(pair.Member)]; ok {
+				tmpMap[String(pair.Member)] = aggregateFunc(score, pair.Score*weights[i+1])
+			}
+		}
+		destMap = tmpMap
+	}
+
+	t := db.zsetBatch
+	t.Lock()
+	defer t.Unlock()
+
+	db.zDelete(t, destKey)
+
+	for member, score := range destMap {
+		if err := checkZSetKMSize(destKey, []byte(member)); err != nil {
+			return 0, err
+		}
+		if _, err := db.zSetItem(t, destKey, score, []byte(member)); err != nil {
+			return 0, err
+		}
+	}
+
+	var num int64 = int64(len(destMap))
+	sk := db.zEncodeSizeKey(destKey)
+	t.Put(sk, PutInt64(num))
+	//todo add binlog
+	if err := t.Commit(); err != nil {
+		return 0, err
+	}
+	return num, nil
+}
+
+func (db *DB) ZScan(key []byte, count int, inclusive bool, match string) ([][]byte, error) {
+	return db.scan(ZSizeType, key, count, inclusive, match)
+}
diff --git a/vendor/github.com/lunny/nodb/tx.go b/vendor/github.com/lunny/nodb/tx.go
new file mode 100644
index 0000000000..5ce99db57a
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/tx.go
@@ -0,0 +1,113 @@
+package nodb
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/lunny/nodb/store"
+)
+
+var (
+	ErrNestTx = errors.New("nest transaction not supported")
+	ErrTxDone = errors.New("Transaction has already been committed or rolled back")
+)
+
+type Tx struct {
+	*DB
+
+	tx *store.Tx
+
+	logs [][]byte
+}
+
+func (db *DB) IsTransaction() bool {
+	return db.status == DBInTransaction
+}
+
+// Begin a transaction, it will block all other write operations before calling Commit or Rollback.
+// You must be very careful to prevent long-time transaction.
+func (db *DB) Begin() (*Tx, error) {
+	if db.IsTransaction() {
+		return nil, ErrNestTx
+	}
+
+	tx := new(Tx)
+
+	tx.DB = new(DB)
+	tx.DB.l = db.l
+
+	tx.l.wLock.Lock()
+
+	tx.DB.sdb = db.sdb
+
+	var err error
+	tx.tx, err = db.sdb.Begin()
+	if err != nil {
+		tx.l.wLock.Unlock()
+		return nil, err
+	}
+
+	tx.DB.bucket = tx.tx
+
+	tx.DB.status = DBInTransaction
+
+	tx.DB.index = db.index
+
+	tx.DB.kvBatch = tx.newBatch()
+	tx.DB.listBatch = tx.newBatch()
+	tx.DB.hashBatch = tx.newBatch()
+	tx.DB.zsetBatch = tx.newBatch()
+	tx.DB.binBatch = tx.newBatch()
+	tx.DB.setBatch = tx.newBatch()
+
+	return tx, nil
+}
+
+func (tx *Tx) Commit() error {
+	if tx.tx == nil {
+		return ErrTxDone
+	}
+
+	tx.l.commitLock.Lock()
+	err := tx.tx.Commit()
+	tx.tx = nil
+
+	if len(tx.logs) > 0 {
+		tx.l.binlog.Log(tx.logs...)
+	}
+
+	tx.l.commitLock.Unlock()
+
+	tx.l.wLock.Unlock()
+
+	tx.DB.bucket = nil
+
+	return err
+}
+
+func (tx *Tx) Rollback() error {
+	if tx.tx == nil {
+		return ErrTxDone
+	}
+
+	err := tx.tx.Rollback()
+	tx.tx = nil
+
+	tx.l.wLock.Unlock()
+	tx.DB.bucket = nil
+
+	return err
+}
+
+func (tx *Tx) newBatch() *batch {
+	return tx.l.newBatch(tx.tx.NewWriteBatch(), &txBatchLocker{}, tx)
+}
+
+func (tx *Tx) Select(index int) error {
+	if index < 0 || index >= int(MaxDBNumber) {
+		return fmt.Errorf("invalid db index %d", index)
+	}
+
+	tx.DB.index = uint8(index)
+	return nil
+}
diff --git a/vendor/github.com/lunny/nodb/util.go b/vendor/github.com/lunny/nodb/util.go
new file mode 100644
index 0000000000..d5949a96e6
--- /dev/null
+++ b/vendor/github.com/lunny/nodb/util.go
@@ -0,0 +1,113 @@
+package nodb
+
+import (
+	"encoding/binary"
+	"errors"
+	"reflect"
+	"strconv"
+	"unsafe"
+)
+
+var errIntNumber = errors.New("invalid integer")
+
+// no copy to change slice to string
+// use your own risk
+func String(b []byte) (s string) {
+	pbytes := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	pstring := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	pstring.Data = pbytes.Data
+	pstring.Len = pbytes.Len
+	return
+}
+
+// no copy to change string to slice
+// use your own risk
+func Slice(s string) (b []byte) {
+	pbytes := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	pstring := (*reflect.StringHeader)(unsafe.Pointer(&s))
+	pbytes.Data = pstring.Data
+	pbytes.Len = pstring.Len
+	pbytes.Cap = pstring.Len
+	return
+}
+
+func Int64(v []byte, err error) (int64, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil || len(v) == 0 {
+		return 0, nil
+	} else if len(v) != 8 {
+		return 0, errIntNumber
+	}
+
+	return int64(binary.LittleEndian.Uint64(v)), nil
+}
+
+func PutInt64(v int64) []byte {
+	var b []byte
+	pbytes := (*reflect.SliceHeader)(unsafe.Pointer(&b))
+	pbytes.Data = uintptr(unsafe.Pointer(&v))
+	pbytes.Len = 8
+	pbytes.Cap = 8
+	return b
+}
+
+func StrInt64(v []byte, err error) (int64, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else {
+		return strconv.ParseInt(String(v), 10, 64)
+	}
+}
+
+func StrInt32(v []byte, err error) (int32, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else {
+		res, err := strconv.ParseInt(String(v), 10, 32)
+		return int32(res), err
+	}
+}
+
+func StrInt8(v []byte, err error) (int8, error) {
+	if err != nil {
+		return 0, err
+	} else if v == nil {
+		return 0, nil
+	} else {
+		res, err := strconv.ParseInt(String(v), 10, 8)
+		return int8(res), err
+	}
+}
+
+func StrPutInt64(v int64) []byte {
+	return strconv.AppendInt(nil, v, 10)
+}
+
+func MinUInt32(a uint32, b uint32) uint32 {
+	if a > b {
+		return b
+	} else {
+		return a
+	}
+}
+
+func MaxUInt32(a uint32, b uint32) uint32 {
+	if a > b {
+		return a
+	} else {
+		return b
+	}
+}
+
+func MaxInt32(a int32, b int32) int32 {
+	if a > b {
+		return a
+	} else {
+		return b
+	}
+}
diff --git a/vendor/github.com/pkg/errors/LICENSE b/vendor/github.com/pkg/errors/LICENSE
new file mode 100644
index 0000000000..835ba3e755
--- /dev/null
+++ b/vendor/github.com/pkg/errors/LICENSE
@@ -0,0 +1,23 @@
+Copyright (c) 2015, Dave Cheney <dave@cheney.net>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/pkg/errors/errors.go b/vendor/github.com/pkg/errors/errors.go
new file mode 100644
index 0000000000..7421f326ff
--- /dev/null
+++ b/vendor/github.com/pkg/errors/errors.go
@@ -0,0 +1,282 @@
+// Package errors provides simple error handling primitives.
+//
+// The traditional error handling idiom in Go is roughly akin to
+//
+//     if err != nil {
+//             return err
+//     }
+//
+// which when applied recursively up the call stack results in error reports
+// without context or debugging information. The errors package allows
+// programmers to add context to the failure path in their code in a way
+// that does not destroy the original value of the error.
+//
+// Adding context to an error
+//
+// The errors.Wrap function returns a new error that adds context to the
+// original error by recording a stack trace at the point Wrap is called,
+// together with the supplied message. For example
+//
+//     _, err := ioutil.ReadAll(r)
+//     if err != nil {
+//             return errors.Wrap(err, "read failed")
+//     }
+//
+// If additional control is required, the errors.WithStack and
+// errors.WithMessage functions destructure errors.Wrap into its component
+// operations: annotating an error with a stack trace and with a message,
+// respectively.
+//
+// Retrieving the cause of an error
+//
+// Using errors.Wrap constructs a stack of errors, adding context to the
+// preceding error. Depending on the nature of the error it may be necessary
+// to reverse the operation of errors.Wrap to retrieve the original error
+// for inspection. Any error value which implements this interface
+//
+//     type causer interface {
+//             Cause() error
+//     }
+//
+// can be inspected by errors.Cause. errors.Cause will recursively retrieve
+// the topmost error that does not implement causer, which is assumed to be
+// the original cause. For example:
+//
+//     switch err := errors.Cause(err).(type) {
+//     case *MyError:
+//             // handle specifically
+//     default:
+//             // unknown error
+//     }
+//
+// Although the causer interface is not exported by this package, it is
+// considered a part of its stable public interface.
+//
+// Formatted printing of errors
+//
+// All error values returned from this package implement fmt.Formatter and can
+// be formatted by the fmt package. The following verbs are supported:
+//
+//     %s    print the error. If the error has a Cause it will be
+//           printed recursively.
+//     %v    see %s
+//     %+v   extended format. Each Frame of the error's StackTrace will
+//           be printed in detail.
+//
+// Retrieving the stack trace of an error or wrapper
+//
+// New, Errorf, Wrap, and Wrapf record a stack trace at the point they are
+// invoked. This information can be retrieved with the following interface:
+//
+//     type stackTracer interface {
+//             StackTrace() errors.StackTrace
+//     }
+//
+// The returned errors.StackTrace type is defined as
+//
+//     type StackTrace []Frame
+//
+// The Frame type represents a call site in the stack trace. Frame supports
+// the fmt.Formatter interface that can be used for printing information about
+// the stack trace of this error. For example:
+//
+//     if err, ok := err.(stackTracer); ok {
+//             for _, f := range err.StackTrace() {
+//                     fmt.Printf("%+s:%d", f)
+//             }
+//     }
+//
+// Although the stackTracer interface is not exported by this package, it is
+// considered a part of its stable public interface.
+//
+// See the documentation for Frame.Format for more details.
+package errors
+
+import (
+	"fmt"
+	"io"
+)
+
+// New returns an error with the supplied message.
+// New also records the stack trace at the point it was called.
+func New(message string) error {
+	return &fundamental{
+		msg:   message,
+		stack: callers(),
+	}
+}
+
+// Errorf formats according to a format specifier and returns the string
+// as a value that satisfies error.
+// Errorf also records the stack trace at the point it was called.
+func Errorf(format string, args ...interface{}) error {
+	return &fundamental{
+		msg:   fmt.Sprintf(format, args...),
+		stack: callers(),
+	}
+}
+
+// fundamental is an error that has a message and a stack, but no caller.
+type fundamental struct {
+	msg string
+	*stack
+}
+
+func (f *fundamental) Error() string { return f.msg }
+
+func (f *fundamental) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		if s.Flag('+') {
+			io.WriteString(s, f.msg)
+			f.stack.Format(s, verb)
+			return
+		}
+		fallthrough
+	case 's':
+		io.WriteString(s, f.msg)
+	case 'q':
+		fmt.Fprintf(s, "%q", f.msg)
+	}
+}
+
+// WithStack annotates err with a stack trace at the point WithStack was called.
+// If err is nil, WithStack returns nil.
+func WithStack(err error) error {
+	if err == nil {
+		return nil
+	}
+	return &withStack{
+		err,
+		callers(),
+	}
+}
+
+type withStack struct {
+	error
+	*stack
+}
+
+func (w *withStack) Cause() error { return w.error }
+
+func (w *withStack) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		if s.Flag('+') {
+			fmt.Fprintf(s, "%+v", w.Cause())
+			w.stack.Format(s, verb)
+			return
+		}
+		fallthrough
+	case 's':
+		io.WriteString(s, w.Error())
+	case 'q':
+		fmt.Fprintf(s, "%q", w.Error())
+	}
+}
+
+// Wrap returns an error annotating err with a stack trace
+// at the point Wrap is called, and the supplied message.
+// If err is nil, Wrap returns nil.
+func Wrap(err error, message string) error {
+	if err == nil {
+		return nil
+	}
+	err = &withMessage{
+		cause: err,
+		msg:   message,
+	}
+	return &withStack{
+		err,
+		callers(),
+	}
+}
+
+// Wrapf returns an error annotating err with a stack trace
+// at the point Wrapf is called, and the format specifier.
+// If err is nil, Wrapf returns nil.
+func Wrapf(err error, format string, args ...interface{}) error {
+	if err == nil {
+		return nil
+	}
+	err = &withMessage{
+		cause: err,
+		msg:   fmt.Sprintf(format, args...),
+	}
+	return &withStack{
+		err,
+		callers(),
+	}
+}
+
+// WithMessage annotates err with a new message.
+// If err is nil, WithMessage returns nil.
+func WithMessage(err error, message string) error {
+	if err == nil {
+		return nil
+	}
+	return &withMessage{
+		cause: err,
+		msg:   message,
+	}
+}
+
+// WithMessagef annotates err with the format specifier.
+// If err is nil, WithMessagef returns nil.
+func WithMessagef(err error, format string, args ...interface{}) error {
+	if err == nil {
+		return nil
+	}
+	return &withMessage{
+		cause: err,
+		msg:   fmt.Sprintf(format, args...),
+	}
+}
+
+type withMessage struct {
+	cause error
+	msg   string
+}
+
+func (w *withMessage) Error() string { return w.msg + ": " + w.cause.Error() }
+func (w *withMessage) Cause() error  { return w.cause }
+
+func (w *withMessage) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		if s.Flag('+') {
+			fmt.Fprintf(s, "%+v\n", w.Cause())
+			io.WriteString(s, w.msg)
+			return
+		}
+		fallthrough
+	case 's', 'q':
+		io.WriteString(s, w.Error())
+	}
+}
+
+// Cause returns the underlying cause of the error, if possible.
+// An error value has a cause if it implements the following
+// interface:
+//
+//     type causer interface {
+//            Cause() error
+//     }
+//
+// If the error does not implement Cause, the original error will
+// be returned. If the error is nil, nil will be returned without further
+// investigation.
+func Cause(err error) error {
+	type causer interface {
+		Cause() error
+	}
+
+	for err != nil {
+		cause, ok := err.(causer)
+		if !ok {
+			break
+		}
+		err = cause.Cause()
+	}
+	return err
+}
diff --git a/vendor/github.com/pkg/errors/stack.go b/vendor/github.com/pkg/errors/stack.go
new file mode 100644
index 0000000000..2874a048cf
--- /dev/null
+++ b/vendor/github.com/pkg/errors/stack.go
@@ -0,0 +1,147 @@
+package errors
+
+import (
+	"fmt"
+	"io"
+	"path"
+	"runtime"
+	"strings"
+)
+
+// Frame represents a program counter inside a stack frame.
+type Frame uintptr
+
+// pc returns the program counter for this frame;
+// multiple frames may have the same PC value.
+func (f Frame) pc() uintptr { return uintptr(f) - 1 }
+
+// file returns the full path to the file that contains the
+// function for this Frame's pc.
+func (f Frame) file() string {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return "unknown"
+	}
+	file, _ := fn.FileLine(f.pc())
+	return file
+}
+
+// line returns the line number of source code of the
+// function for this Frame's pc.
+func (f Frame) line() int {
+	fn := runtime.FuncForPC(f.pc())
+	if fn == nil {
+		return 0
+	}
+	_, line := fn.FileLine(f.pc())
+	return line
+}
+
+// Format formats the frame according to the fmt.Formatter interface.
+//
+//    %s    source file
+//    %d    source line
+//    %n    function name
+//    %v    equivalent to %s:%d
+//
+// Format accepts flags that alter the printing of some verbs, as follows:
+//
+//    %+s   function name and path of source file relative to the compile time
+//          GOPATH separated by \n\t (<funcname>\n\t<path>)
+//    %+v   equivalent to %+s:%d
+func (f Frame) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 's':
+		switch {
+		case s.Flag('+'):
+			pc := f.pc()
+			fn := runtime.FuncForPC(pc)
+			if fn == nil {
+				io.WriteString(s, "unknown")
+			} else {
+				file, _ := fn.FileLine(pc)
+				fmt.Fprintf(s, "%s\n\t%s", fn.Name(), file)
+			}
+		default:
+			io.WriteString(s, path.Base(f.file()))
+		}
+	case 'd':
+		fmt.Fprintf(s, "%d", f.line())
+	case 'n':
+		name := runtime.FuncForPC(f.pc()).Name()
+		io.WriteString(s, funcname(name))
+	case 'v':
+		f.Format(s, 's')
+		io.WriteString(s, ":")
+		f.Format(s, 'd')
+	}
+}
+
+// StackTrace is stack of Frames from innermost (newest) to outermost (oldest).
+type StackTrace []Frame
+
+// Format formats the stack of Frames according to the fmt.Formatter interface.
+//
+//    %s	lists source files for each Frame in the stack
+//    %v	lists the source file and line number for each Frame in the stack
+//
+// Format accepts flags that alter the printing of some verbs, as follows:
+//
+//    %+v   Prints filename, function, and line number for each Frame in the stack.
+func (st StackTrace) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case s.Flag('+'):
+			for _, f := range st {
+				fmt.Fprintf(s, "\n%+v", f)
+			}
+		case s.Flag('#'):
+			fmt.Fprintf(s, "%#v", []Frame(st))
+		default:
+			fmt.Fprintf(s, "%v", []Frame(st))
+		}
+	case 's':
+		fmt.Fprintf(s, "%s", []Frame(st))
+	}
+}
+
+// stack represents a stack of program counters.
+type stack []uintptr
+
+func (s *stack) Format(st fmt.State, verb rune) {
+	switch verb {
+	case 'v':
+		switch {
+		case st.Flag('+'):
+			for _, pc := range *s {
+				f := Frame(pc)
+				fmt.Fprintf(st, "\n%+v", f)
+			}
+		}
+	}
+}
+
+func (s *stack) StackTrace() StackTrace {
+	f := make([]Frame, len(*s))
+	for i := 0; i < len(f); i++ {
+		f[i] = Frame((*s)[i])
+	}
+	return f
+}
+
+func callers() *stack {
+	const depth = 32
+	var pcs [depth]uintptr
+	n := runtime.Callers(3, pcs[:])
+	var st stack = pcs[0:n]
+	return &st
+}
+
+// funcname removes the path prefix component of a function's name reported by func.Name().
+func funcname(name string) string {
+	i := strings.LastIndex(name, "/")
+	name = name[i+1:]
+	i = strings.Index(name, ".")
+	return name[i+1:]
+}
diff --git a/vendor/github.com/siddontang/go-snappy/AUTHORS b/vendor/github.com/siddontang/go-snappy/AUTHORS
new file mode 100644
index 0000000000..8ddb5b7a2b
--- /dev/null
+++ b/vendor/github.com/siddontang/go-snappy/AUTHORS
@@ -0,0 +1,12 @@
+# This is the official list of Snappy-Go authors for copyright purposes.
+# This file is distinct from the CONTRIBUTORS files.
+# See the latter for an explanation.
+
+# Names should be added to this file as
+#	Name or Organization <email address>
+# The email address is not required for organizations.
+
+# Please keep the list sorted.
+
+Google Inc.
+Jan Mercl <0xjnml@gmail.com>
diff --git a/vendor/github.com/siddontang/go-snappy/CONTRIBUTORS b/vendor/github.com/siddontang/go-snappy/CONTRIBUTORS
new file mode 100644
index 0000000000..50b69c80ea
--- /dev/null
+++ b/vendor/github.com/siddontang/go-snappy/CONTRIBUTORS
@@ -0,0 +1,34 @@
+# This is the official list of people who can contribute
+# (and typically have contributed) code to the Snappy-Go repository.
+# The AUTHORS file lists the copyright holders; this file
+# lists people.  For example, Google employees are listed here
+# but not in AUTHORS, because Google holds the copyright.
+#
+# The submission process automatically checks to make sure
+# that people submitting code are listed in this file (by email address).
+#
+# Names should be added to this file only after verifying that
+# the individual or the individual's organization has agreed to
+# the appropriate Contributor License Agreement, found here:
+#
+#     http://code.google.com/legal/individual-cla-v1.0.html
+#     http://code.google.com/legal/corporate-cla-v1.0.html
+#
+# The agreement for individuals can be filled out on the web.
+#
+# When adding J Random Contributor's name to this file,
+# either J's name or J's organization's name should be
+# added to the AUTHORS file, depending on whether the
+# individual or corporate CLA was used.
+
+# Names should be added to this file like so:
+#     Name <email address>
+
+# Please keep the list sorted.
+
+Jan Mercl <0xjnml@gmail.com>
+Kai Backman <kaib@golang.org>
+Marc-Antoine Ruel <maruel@chromium.org>
+Nigel Tao <nigeltao@golang.org>
+Rob Pike <r@golang.org>
+Russ Cox <rsc@golang.org>
diff --git a/vendor/github.com/siddontang/go-snappy/LICENSE b/vendor/github.com/siddontang/go-snappy/LICENSE
new file mode 100644
index 0000000000..6050c10f4c
--- /dev/null
+++ b/vendor/github.com/siddontang/go-snappy/LICENSE
@@ -0,0 +1,27 @@
+Copyright (c) 2011 The Snappy-Go Authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+   * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+   * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+   * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/siddontang/go-snappy/snappy/decode.go b/vendor/github.com/siddontang/go-snappy/snappy/decode.go
new file mode 100644
index 0000000000..d93c1b9dbf
--- /dev/null
+++ b/vendor/github.com/siddontang/go-snappy/snappy/decode.go
@@ -0,0 +1,124 @@
+// Copyright 2011 The Snappy-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package snappy
+
+import (
+	"encoding/binary"
+	"errors"
+)
+
+// ErrCorrupt reports that the input is invalid.
+var ErrCorrupt = errors.New("snappy: corrupt input")
+
+// DecodedLen returns the length of the decoded block.
+func DecodedLen(src []byte) (int, error) {
+	v, _, err := decodedLen(src)
+	return v, err
+}
+
+// decodedLen returns the length of the decoded block and the number of bytes
+// that the length header occupied.
+func decodedLen(src []byte) (blockLen, headerLen int, err error) {
+	v, n := binary.Uvarint(src)
+	if n == 0 {
+		return 0, 0, ErrCorrupt
+	}
+	if uint64(int(v)) != v {
+		return 0, 0, errors.New("snappy: decoded block is too large")
+	}
+	return int(v), n, nil
+}
+
+// Decode returns the decoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire decoded block.
+// Otherwise, a newly allocated slice will be returned.
+// It is valid to pass a nil dst.
+func Decode(dst, src []byte) ([]byte, error) {
+	dLen, s, err := decodedLen(src)
+	if err != nil {
+		return nil, err
+	}
+	if len(dst) < dLen {
+		dst = make([]byte, dLen)
+	}
+
+	var d, offset, length int
+	for s < len(src) {
+		switch src[s] & 0x03 {
+		case tagLiteral:
+			x := uint(src[s] >> 2)
+			switch {
+			case x < 60:
+				s += 1
+			case x == 60:
+				s += 2
+				if s > len(src) {
+					return nil, ErrCorrupt
+				}
+				x = uint(src[s-1])
+			case x == 61:
+				s += 3
+				if s > len(src) {
+					return nil, ErrCorrupt
+				}
+				x = uint(src[s-2]) | uint(src[s-1])<<8
+			case x == 62:
+				s += 4
+				if s > len(src) {
+					return nil, ErrCorrupt
+				}
+				x = uint(src[s-3]) | uint(src[s-2])<<8 | uint(src[s-1])<<16
+			case x == 63:
+				s += 5
+				if s > len(src) {
+					return nil, ErrCorrupt
+				}
+				x = uint(src[s-4]) | uint(src[s-3])<<8 | uint(src[s-2])<<16 | uint(src[s-1])<<24
+			}
+			length = int(x + 1)
+			if length <= 0 {
+				return nil, errors.New("snappy: unsupported literal length")
+			}
+			if length > len(dst)-d || length > len(src)-s {
+				return nil, ErrCorrupt
+			}
+			copy(dst[d:], src[s:s+length])
+			d += length
+			s += length
+			continue
+
+		case tagCopy1:
+			s += 2
+			if s > len(src) {
+				return nil, ErrCorrupt
+			}
+			length = 4 + int(src[s-2])>>2&0x7
+			offset = int(src[s-2])&0xe0<<3 | int(src[s-1])
+
+		case tagCopy2:
+			s += 3
+			if s > len(src) {
+				return nil, ErrCorrupt
+			}
+			length = 1 + int(src[s-3])>>2
+			offset = int(src[s-2]) | int(src[s-1])<<8
+
+		case tagCopy4:
+			return nil, errors.New("snappy: unsupported COPY_4 tag")
+		}
+
+		end := d + length
+		if offset > d || end > len(dst) {
+			return nil, ErrCorrupt
+		}
+		for ; d < end; d++ {
+			dst[d] = dst[d-offset]
+		}
+	}
+	if d != dLen {
+		return nil, ErrCorrupt
+	}
+	return dst[:d], nil
+}
diff --git a/vendor/github.com/siddontang/go-snappy/snappy/encode.go b/vendor/github.com/siddontang/go-snappy/snappy/encode.go
new file mode 100644
index 0000000000..b2371db11c
--- /dev/null
+++ b/vendor/github.com/siddontang/go-snappy/snappy/encode.go
@@ -0,0 +1,174 @@
+// Copyright 2011 The Snappy-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package snappy
+
+import (
+	"encoding/binary"
+)
+
+// We limit how far copy back-references can go, the same as the C++ code.
+const maxOffset = 1 << 15
+
+// emitLiteral writes a literal chunk and returns the number of bytes written.
+func emitLiteral(dst, lit []byte) int {
+	i, n := 0, uint(len(lit)-1)
+	switch {
+	case n < 60:
+		dst[0] = uint8(n)<<2 | tagLiteral
+		i = 1
+	case n < 1<<8:
+		dst[0] = 60<<2 | tagLiteral
+		dst[1] = uint8(n)
+		i = 2
+	case n < 1<<16:
+		dst[0] = 61<<2 | tagLiteral
+		dst[1] = uint8(n)
+		dst[2] = uint8(n >> 8)
+		i = 3
+	case n < 1<<24:
+		dst[0] = 62<<2 | tagLiteral
+		dst[1] = uint8(n)
+		dst[2] = uint8(n >> 8)
+		dst[3] = uint8(n >> 16)
+		i = 4
+	case int64(n) < 1<<32:
+		dst[0] = 63<<2 | tagLiteral
+		dst[1] = uint8(n)
+		dst[2] = uint8(n >> 8)
+		dst[3] = uint8(n >> 16)
+		dst[4] = uint8(n >> 24)
+		i = 5
+	default:
+		panic("snappy: source buffer is too long")
+	}
+	if copy(dst[i:], lit) != len(lit) {
+		panic("snappy: destination buffer is too short")
+	}
+	return i + len(lit)
+}
+
+// emitCopy writes a copy chunk and returns the number of bytes written.
+func emitCopy(dst []byte, offset, length int) int {
+	i := 0
+	for length > 0 {
+		x := length - 4
+		if 0 <= x && x < 1<<3 && offset < 1<<11 {
+			dst[i+0] = uint8(offset>>8)&0x07<<5 | uint8(x)<<2 | tagCopy1
+			dst[i+1] = uint8(offset)
+			i += 2
+			break
+		}
+
+		x = length
+		if x > 1<<6 {
+			x = 1 << 6
+		}
+		dst[i+0] = uint8(x-1)<<2 | tagCopy2
+		dst[i+1] = uint8(offset)
+		dst[i+2] = uint8(offset >> 8)
+		i += 3
+		length -= x
+	}
+	return i
+}
+
+// Encode returns the encoded form of src. The returned slice may be a sub-
+// slice of dst if dst was large enough to hold the entire encoded block.
+// Otherwise, a newly allocated slice will be returned.
+// It is valid to pass a nil dst.
+func Encode(dst, src []byte) ([]byte, error) {
+	if n := MaxEncodedLen(len(src)); len(dst) < n {
+		dst = make([]byte, n)
+	}
+
+	// The block starts with the varint-encoded length of the decompressed bytes.
+	d := binary.PutUvarint(dst, uint64(len(src)))
+
+	// Return early if src is short.
+	if len(src) <= 4 {
+		if len(src) != 0 {
+			d += emitLiteral(dst[d:], src)
+		}
+		return dst[:d], nil
+	}
+
+	// Initialize the hash table. Its size ranges from 1<<8 to 1<<14 inclusive.
+	const maxTableSize = 1 << 14
+	shift, tableSize := uint(32-8), 1<<8
+	for tableSize < maxTableSize && tableSize < len(src) {
+		shift--
+		tableSize *= 2
+	}
+	var table [maxTableSize]int
+
+	// Iterate over the source bytes.
+	var (
+		s   int // The iterator position.
+		t   int // The last position with the same hash as s.
+		lit int // The start position of any pending literal bytes.
+	)
+	for s+3 < len(src) {
+		// Update the hash table.
+		b0, b1, b2, b3 := src[s], src[s+1], src[s+2], src[s+3]
+		h := uint32(b0) | uint32(b1)<<8 | uint32(b2)<<16 | uint32(b3)<<24
+		p := &table[(h*0x1e35a7bd)>>shift]
+		// We need to to store values in [-1, inf) in table. To save
+		// some initialization time, (re)use the table's zero value
+		// and shift the values against this zero: add 1 on writes,
+		// subtract 1 on reads.
+		t, *p = *p-1, s+1
+		// If t is invalid or src[s:s+4] differs from src[t:t+4], accumulate a literal byte.
+		if t < 0 || s-t >= maxOffset || b0 != src[t] || b1 != src[t+1] || b2 != src[t+2] || b3 != src[t+3] {
+			s++
+			continue
+		}
+		// Otherwise, we have a match. First, emit any pending literal bytes.
+		if lit != s {
+			d += emitLiteral(dst[d:], src[lit:s])
+		}
+		// Extend the match to be as long as possible.
+		s0 := s
+		s, t = s+4, t+4
+		for s < len(src) && src[s] == src[t] {
+			s++
+			t++
+		}
+		// Emit the copied bytes.
+		d += emitCopy(dst[d:], s-t, s-s0)
+		lit = s
+	}
+
+	// Emit any final pending literal bytes and return.
+	if lit != len(src) {
+		d += emitLiteral(dst[d:], src[lit:])
+	}
+	return dst[:d], nil
+}
+
+// MaxEncodedLen returns the maximum length of a snappy block, given its
+// uncompressed length.
+func MaxEncodedLen(srcLen int) int {
+	// Compressed data can be defined as:
+	//    compressed := item* literal*
+	//    item       := literal* copy
+	//
+	// The trailing literal sequence has a space blowup of at most 62/60
+	// since a literal of length 60 needs one tag byte + one extra byte
+	// for length information.
+	//
+	// Item blowup is trickier to measure. Suppose the "copy" op copies
+	// 4 bytes of data. Because of a special check in the encoding code,
+	// we produce a 4-byte copy only if the offset is < 65536. Therefore
+	// the copy op takes 3 bytes to encode, and this type of item leads
+	// to at most the 62/60 blowup for representing literals.
+	//
+	// Suppose the "copy" op copies 5 bytes of data. If the offset is big
+	// enough, it will take 5 bytes to encode the copy op. Therefore the
+	// worst case here is a one-byte literal followed by a five-byte copy.
+	// That is, 6 bytes of input turn into 7 bytes of "compressed" data.
+	//
+	// This last factor dominates the blowup, so the final estimate is:
+	return 32 + srcLen + srcLen/6
+}
diff --git a/vendor/github.com/siddontang/go-snappy/snappy/snappy.go b/vendor/github.com/siddontang/go-snappy/snappy/snappy.go
new file mode 100644
index 0000000000..2f1b790d0b
--- /dev/null
+++ b/vendor/github.com/siddontang/go-snappy/snappy/snappy.go
@@ -0,0 +1,38 @@
+// Copyright 2011 The Snappy-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package snappy implements the snappy block-based compression format.
+// It aims for very high speeds and reasonable compression.
+//
+// The C++ snappy implementation is at http://code.google.com/p/snappy/
+package snappy
+
+/*
+Each encoded block begins with the varint-encoded length of the decoded data,
+followed by a sequence of chunks. Chunks begin and end on byte boundaries. The
+first byte of each chunk is broken into its 2 least and 6 most significant bits
+called l and m: l ranges in [0, 4) and m ranges in [0, 64). l is the chunk tag.
+Zero means a literal tag. All other values mean a copy tag.
+
+For literal tags:
+  - If m < 60, the next 1 + m bytes are literal bytes.
+  - Otherwise, let n be the little-endian unsigned integer denoted by the next
+    m - 59 bytes. The next 1 + n bytes after that are literal bytes.
+
+For copy tags, length bytes are copied from offset bytes ago, in the style of
+Lempel-Ziv compression algorithms. In particular:
+  - For l == 1, the offset ranges in [0, 1<<11) and the length in [4, 12).
+    The length is 4 + the low 3 bits of m. The high 3 bits of m form bits 8-10
+    of the offset. The next byte is bits 0-7 of the offset.
+  - For l == 2, the offset ranges in [0, 1<<16) and the length in [1, 65).
+    The length is 1 + m. The offset is the little-endian unsigned integer
+    denoted by the next 2 bytes.
+  - For l == 3, this tag is a legacy format that is no longer supported.
+*/
+const (
+	tagLiteral = 0x00
+	tagCopy1   = 0x01
+	tagCopy2   = 0x02
+	tagCopy4   = 0x03
+)
diff --git a/vendor/github.com/syndtr/goleveldb/LICENSE b/vendor/github.com/syndtr/goleveldb/LICENSE
new file mode 100644
index 0000000000..4a772d1ab3
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/LICENSE
@@ -0,0 +1,24 @@
+Copyright 2012 Suryandaru Triandana <syndtr@gmail.com>
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+notice, this list of conditions and the following disclaimer in the
+documentation and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/batch.go b/vendor/github.com/syndtr/goleveldb/leveldb/batch.go
new file mode 100644
index 0000000000..225920002d
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/batch.go
@@ -0,0 +1,349 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/memdb"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+// ErrBatchCorrupted records reason of batch corruption. This error will be
+// wrapped with errors.ErrCorrupted.
+type ErrBatchCorrupted struct {
+	Reason string
+}
+
+func (e *ErrBatchCorrupted) Error() string {
+	return fmt.Sprintf("leveldb: batch corrupted: %s", e.Reason)
+}
+
+func newErrBatchCorrupted(reason string) error {
+	return errors.NewErrCorrupted(storage.FileDesc{}, &ErrBatchCorrupted{reason})
+}
+
+const (
+	batchHeaderLen = 8 + 4
+	batchGrowRec   = 3000
+	batchBufioSize = 16
+)
+
+// BatchReplay wraps basic batch operations.
+type BatchReplay interface {
+	Put(key, value []byte)
+	Delete(key []byte)
+}
+
+type batchIndex struct {
+	keyType            keyType
+	keyPos, keyLen     int
+	valuePos, valueLen int
+}
+
+func (index batchIndex) k(data []byte) []byte {
+	return data[index.keyPos : index.keyPos+index.keyLen]
+}
+
+func (index batchIndex) v(data []byte) []byte {
+	if index.valueLen != 0 {
+		return data[index.valuePos : index.valuePos+index.valueLen]
+	}
+	return nil
+}
+
+func (index batchIndex) kv(data []byte) (key, value []byte) {
+	return index.k(data), index.v(data)
+}
+
+// Batch is a write batch.
+type Batch struct {
+	data  []byte
+	index []batchIndex
+
+	// internalLen is sums of key/value pair length plus 8-bytes internal key.
+	internalLen int
+}
+
+func (b *Batch) grow(n int) {
+	o := len(b.data)
+	if cap(b.data)-o < n {
+		div := 1
+		if len(b.index) > batchGrowRec {
+			div = len(b.index) / batchGrowRec
+		}
+		ndata := make([]byte, o, o+n+o/div)
+		copy(ndata, b.data)
+		b.data = ndata
+	}
+}
+
+func (b *Batch) appendRec(kt keyType, key, value []byte) {
+	n := 1 + binary.MaxVarintLen32 + len(key)
+	if kt == keyTypeVal {
+		n += binary.MaxVarintLen32 + len(value)
+	}
+	b.grow(n)
+	index := batchIndex{keyType: kt}
+	o := len(b.data)
+	data := b.data[:o+n]
+	data[o] = byte(kt)
+	o++
+	o += binary.PutUvarint(data[o:], uint64(len(key)))
+	index.keyPos = o
+	index.keyLen = len(key)
+	o += copy(data[o:], key)
+	if kt == keyTypeVal {
+		o += binary.PutUvarint(data[o:], uint64(len(value)))
+		index.valuePos = o
+		index.valueLen = len(value)
+		o += copy(data[o:], value)
+	}
+	b.data = data[:o]
+	b.index = append(b.index, index)
+	b.internalLen += index.keyLen + index.valueLen + 8
+}
+
+// Put appends 'put operation' of the given key/value pair to the batch.
+// It is safe to modify the contents of the argument after Put returns but not
+// before.
+func (b *Batch) Put(key, value []byte) {
+	b.appendRec(keyTypeVal, key, value)
+}
+
+// Delete appends 'delete operation' of the given key to the batch.
+// It is safe to modify the contents of the argument after Delete returns but
+// not before.
+func (b *Batch) Delete(key []byte) {
+	b.appendRec(keyTypeDel, key, nil)
+}
+
+// Dump dumps batch contents. The returned slice can be loaded into the
+// batch using Load method.
+// The returned slice is not its own copy, so the contents should not be
+// modified.
+func (b *Batch) Dump() []byte {
+	return b.data
+}
+
+// Load loads given slice into the batch. Previous contents of the batch
+// will be discarded.
+// The given slice will not be copied and will be used as batch buffer, so
+// it is not safe to modify the contents of the slice.
+func (b *Batch) Load(data []byte) error {
+	return b.decode(data, -1)
+}
+
+// Replay replays batch contents.
+func (b *Batch) Replay(r BatchReplay) error {
+	for _, index := range b.index {
+		switch index.keyType {
+		case keyTypeVal:
+			r.Put(index.k(b.data), index.v(b.data))
+		case keyTypeDel:
+			r.Delete(index.k(b.data))
+		}
+	}
+	return nil
+}
+
+// Len returns number of records in the batch.
+func (b *Batch) Len() int {
+	return len(b.index)
+}
+
+// Reset resets the batch.
+func (b *Batch) Reset() {
+	b.data = b.data[:0]
+	b.index = b.index[:0]
+	b.internalLen = 0
+}
+
+func (b *Batch) replayInternal(fn func(i int, kt keyType, k, v []byte) error) error {
+	for i, index := range b.index {
+		if err := fn(i, index.keyType, index.k(b.data), index.v(b.data)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (b *Batch) append(p *Batch) {
+	ob := len(b.data)
+	oi := len(b.index)
+	b.data = append(b.data, p.data...)
+	b.index = append(b.index, p.index...)
+	b.internalLen += p.internalLen
+
+	// Updating index offset.
+	if ob != 0 {
+		for ; oi < len(b.index); oi++ {
+			index := &b.index[oi]
+			index.keyPos += ob
+			if index.valueLen != 0 {
+				index.valuePos += ob
+			}
+		}
+	}
+}
+
+func (b *Batch) decode(data []byte, expectedLen int) error {
+	b.data = data
+	b.index = b.index[:0]
+	b.internalLen = 0
+	err := decodeBatch(data, func(i int, index batchIndex) error {
+		b.index = append(b.index, index)
+		b.internalLen += index.keyLen + index.valueLen + 8
+		return nil
+	})
+	if err != nil {
+		return err
+	}
+	if expectedLen >= 0 && len(b.index) != expectedLen {
+		return newErrBatchCorrupted(fmt.Sprintf("invalid records length: %d vs %d", expectedLen, len(b.index)))
+	}
+	return nil
+}
+
+func (b *Batch) putMem(seq uint64, mdb *memdb.DB) error {
+	var ik []byte
+	for i, index := range b.index {
+		ik = makeInternalKey(ik, index.k(b.data), seq+uint64(i), index.keyType)
+		if err := mdb.Put(ik, index.v(b.data)); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (b *Batch) revertMem(seq uint64, mdb *memdb.DB) error {
+	var ik []byte
+	for i, index := range b.index {
+		ik = makeInternalKey(ik, index.k(b.data), seq+uint64(i), index.keyType)
+		if err := mdb.Delete(ik); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func newBatch() interface{} {
+	return &Batch{}
+}
+
+func decodeBatch(data []byte, fn func(i int, index batchIndex) error) error {
+	var index batchIndex
+	for i, o := 0, 0; o < len(data); i++ {
+		// Key type.
+		index.keyType = keyType(data[o])
+		if index.keyType > keyTypeVal {
+			return newErrBatchCorrupted(fmt.Sprintf("bad record: invalid type %#x", uint(index.keyType)))
+		}
+		o++
+
+		// Key.
+		x, n := binary.Uvarint(data[o:])
+		o += n
+		if n <= 0 || o+int(x) > len(data) {
+			return newErrBatchCorrupted("bad record: invalid key length")
+		}
+		index.keyPos = o
+		index.keyLen = int(x)
+		o += index.keyLen
+
+		// Value.
+		if index.keyType == keyTypeVal {
+			x, n = binary.Uvarint(data[o:])
+			o += n
+			if n <= 0 || o+int(x) > len(data) {
+				return newErrBatchCorrupted("bad record: invalid value length")
+			}
+			index.valuePos = o
+			index.valueLen = int(x)
+			o += index.valueLen
+		} else {
+			index.valuePos = 0
+			index.valueLen = 0
+		}
+
+		if err := fn(i, index); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func decodeBatchToMem(data []byte, expectSeq uint64, mdb *memdb.DB) (seq uint64, batchLen int, err error) {
+	seq, batchLen, err = decodeBatchHeader(data)
+	if err != nil {
+		return 0, 0, err
+	}
+	if seq < expectSeq {
+		return 0, 0, newErrBatchCorrupted("invalid sequence number")
+	}
+	data = data[batchHeaderLen:]
+	var ik []byte
+	var decodedLen int
+	err = decodeBatch(data, func(i int, index batchIndex) error {
+		if i >= batchLen {
+			return newErrBatchCorrupted("invalid records length")
+		}
+		ik = makeInternalKey(ik, index.k(data), seq+uint64(i), index.keyType)
+		if err := mdb.Put(ik, index.v(data)); err != nil {
+			return err
+		}
+		decodedLen++
+		return nil
+	})
+	if err == nil && decodedLen != batchLen {
+		err = newErrBatchCorrupted(fmt.Sprintf("invalid records length: %d vs %d", batchLen, decodedLen))
+	}
+	return
+}
+
+func encodeBatchHeader(dst []byte, seq uint64, batchLen int) []byte {
+	dst = ensureBuffer(dst, batchHeaderLen)
+	binary.LittleEndian.PutUint64(dst, seq)
+	binary.LittleEndian.PutUint32(dst[8:], uint32(batchLen))
+	return dst
+}
+
+func decodeBatchHeader(data []byte) (seq uint64, batchLen int, err error) {
+	if len(data) < batchHeaderLen {
+		return 0, 0, newErrBatchCorrupted("too short")
+	}
+
+	seq = binary.LittleEndian.Uint64(data)
+	batchLen = int(binary.LittleEndian.Uint32(data[8:]))
+	if batchLen < 0 {
+		return 0, 0, newErrBatchCorrupted("invalid records length")
+	}
+	return
+}
+
+func batchesLen(batches []*Batch) int {
+	batchLen := 0
+	for _, batch := range batches {
+		batchLen += batch.Len()
+	}
+	return batchLen
+}
+
+func writeBatchesWithHeader(wr io.Writer, batches []*Batch, seq uint64) error {
+	if _, err := wr.Write(encodeBatchHeader(nil, seq, batchesLen(batches))); err != nil {
+		return err
+	}
+	for _, batch := range batches {
+		if _, err := wr.Write(batch.data); err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/cache/cache.go b/vendor/github.com/syndtr/goleveldb/leveldb/cache/cache.go
new file mode 100644
index 0000000000..c36ad32359
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/cache/cache.go
@@ -0,0 +1,704 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package cache provides interface and implementation of a cache algorithms.
+package cache
+
+import (
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// Cacher provides interface to implements a caching functionality.
+// An implementation must be safe for concurrent use.
+type Cacher interface {
+	// Capacity returns cache capacity.
+	Capacity() int
+
+	// SetCapacity sets cache capacity.
+	SetCapacity(capacity int)
+
+	// Promote promotes the 'cache node'.
+	Promote(n *Node)
+
+	// Ban evicts the 'cache node' and prevent subsequent 'promote'.
+	Ban(n *Node)
+
+	// Evict evicts the 'cache node'.
+	Evict(n *Node)
+
+	// EvictNS evicts 'cache node' with the given namespace.
+	EvictNS(ns uint64)
+
+	// EvictAll evicts all 'cache node'.
+	EvictAll()
+
+	// Close closes the 'cache tree'
+	Close() error
+}
+
+// Value is a 'cacheable object'. It may implements util.Releaser, if
+// so the the Release method will be called once object is released.
+type Value interface{}
+
+// NamespaceGetter provides convenient wrapper for namespace.
+type NamespaceGetter struct {
+	Cache *Cache
+	NS    uint64
+}
+
+// Get simply calls Cache.Get() method.
+func (g *NamespaceGetter) Get(key uint64, setFunc func() (size int, value Value)) *Handle {
+	return g.Cache.Get(g.NS, key, setFunc)
+}
+
+// The hash tables implementation is based on:
+// "Dynamic-Sized Nonblocking Hash Tables", by Yujie Liu,
+// Kunlong Zhang, and Michael Spear.
+// ACM Symposium on Principles of Distributed Computing, Jul 2014.
+
+const (
+	mInitialSize           = 1 << 4
+	mOverflowThreshold     = 1 << 5
+	mOverflowGrowThreshold = 1 << 7
+)
+
+type mBucket struct {
+	mu     sync.Mutex
+	node   []*Node
+	frozen bool
+}
+
+func (b *mBucket) freeze() []*Node {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	if !b.frozen {
+		b.frozen = true
+	}
+	return b.node
+}
+
+func (b *mBucket) get(r *Cache, h *mNode, hash uint32, ns, key uint64, noset bool) (done, added bool, n *Node) {
+	b.mu.Lock()
+
+	if b.frozen {
+		b.mu.Unlock()
+		return
+	}
+
+	// Scan the node.
+	for _, n := range b.node {
+		if n.hash == hash && n.ns == ns && n.key == key {
+			atomic.AddInt32(&n.ref, 1)
+			b.mu.Unlock()
+			return true, false, n
+		}
+	}
+
+	// Get only.
+	if noset {
+		b.mu.Unlock()
+		return true, false, nil
+	}
+
+	// Create node.
+	n = &Node{
+		r:    r,
+		hash: hash,
+		ns:   ns,
+		key:  key,
+		ref:  1,
+	}
+	// Add node to bucket.
+	b.node = append(b.node, n)
+	bLen := len(b.node)
+	b.mu.Unlock()
+
+	// Update counter.
+	grow := atomic.AddInt32(&r.nodes, 1) >= h.growThreshold
+	if bLen > mOverflowThreshold {
+		grow = grow || atomic.AddInt32(&h.overflow, 1) >= mOverflowGrowThreshold
+	}
+
+	// Grow.
+	if grow && atomic.CompareAndSwapInt32(&h.resizeInProgess, 0, 1) {
+		nhLen := len(h.buckets) << 1
+		nh := &mNode{
+			buckets:         make([]unsafe.Pointer, nhLen),
+			mask:            uint32(nhLen) - 1,
+			pred:            unsafe.Pointer(h),
+			growThreshold:   int32(nhLen * mOverflowThreshold),
+			shrinkThreshold: int32(nhLen >> 1),
+		}
+		ok := atomic.CompareAndSwapPointer(&r.mHead, unsafe.Pointer(h), unsafe.Pointer(nh))
+		if !ok {
+			panic("BUG: failed swapping head")
+		}
+		go nh.initBuckets()
+	}
+
+	return true, true, n
+}
+
+func (b *mBucket) delete(r *Cache, h *mNode, hash uint32, ns, key uint64) (done, deleted bool) {
+	b.mu.Lock()
+
+	if b.frozen {
+		b.mu.Unlock()
+		return
+	}
+
+	// Scan the node.
+	var (
+		n    *Node
+		bLen int
+	)
+	for i := range b.node {
+		n = b.node[i]
+		if n.ns == ns && n.key == key {
+			if atomic.LoadInt32(&n.ref) == 0 {
+				deleted = true
+
+				// Call releaser.
+				if n.value != nil {
+					if r, ok := n.value.(util.Releaser); ok {
+						r.Release()
+					}
+					n.value = nil
+				}
+
+				// Remove node from bucket.
+				b.node = append(b.node[:i], b.node[i+1:]...)
+				bLen = len(b.node)
+			}
+			break
+		}
+	}
+	b.mu.Unlock()
+
+	if deleted {
+		// Call OnDel.
+		for _, f := range n.onDel {
+			f()
+		}
+
+		// Update counter.
+		atomic.AddInt32(&r.size, int32(n.size)*-1)
+		shrink := atomic.AddInt32(&r.nodes, -1) < h.shrinkThreshold
+		if bLen >= mOverflowThreshold {
+			atomic.AddInt32(&h.overflow, -1)
+		}
+
+		// Shrink.
+		if shrink && len(h.buckets) > mInitialSize && atomic.CompareAndSwapInt32(&h.resizeInProgess, 0, 1) {
+			nhLen := len(h.buckets) >> 1
+			nh := &mNode{
+				buckets:         make([]unsafe.Pointer, nhLen),
+				mask:            uint32(nhLen) - 1,
+				pred:            unsafe.Pointer(h),
+				growThreshold:   int32(nhLen * mOverflowThreshold),
+				shrinkThreshold: int32(nhLen >> 1),
+			}
+			ok := atomic.CompareAndSwapPointer(&r.mHead, unsafe.Pointer(h), unsafe.Pointer(nh))
+			if !ok {
+				panic("BUG: failed swapping head")
+			}
+			go nh.initBuckets()
+		}
+	}
+
+	return true, deleted
+}
+
+type mNode struct {
+	buckets         []unsafe.Pointer // []*mBucket
+	mask            uint32
+	pred            unsafe.Pointer // *mNode
+	resizeInProgess int32
+
+	overflow        int32
+	growThreshold   int32
+	shrinkThreshold int32
+}
+
+func (n *mNode) initBucket(i uint32) *mBucket {
+	if b := (*mBucket)(atomic.LoadPointer(&n.buckets[i])); b != nil {
+		return b
+	}
+
+	p := (*mNode)(atomic.LoadPointer(&n.pred))
+	if p != nil {
+		var node []*Node
+		if n.mask > p.mask {
+			// Grow.
+			pb := (*mBucket)(atomic.LoadPointer(&p.buckets[i&p.mask]))
+			if pb == nil {
+				pb = p.initBucket(i & p.mask)
+			}
+			m := pb.freeze()
+			// Split nodes.
+			for _, x := range m {
+				if x.hash&n.mask == i {
+					node = append(node, x)
+				}
+			}
+		} else {
+			// Shrink.
+			pb0 := (*mBucket)(atomic.LoadPointer(&p.buckets[i]))
+			if pb0 == nil {
+				pb0 = p.initBucket(i)
+			}
+			pb1 := (*mBucket)(atomic.LoadPointer(&p.buckets[i+uint32(len(n.buckets))]))
+			if pb1 == nil {
+				pb1 = p.initBucket(i + uint32(len(n.buckets)))
+			}
+			m0 := pb0.freeze()
+			m1 := pb1.freeze()
+			// Merge nodes.
+			node = make([]*Node, 0, len(m0)+len(m1))
+			node = append(node, m0...)
+			node = append(node, m1...)
+		}
+		b := &mBucket{node: node}
+		if atomic.CompareAndSwapPointer(&n.buckets[i], nil, unsafe.Pointer(b)) {
+			if len(node) > mOverflowThreshold {
+				atomic.AddInt32(&n.overflow, int32(len(node)-mOverflowThreshold))
+			}
+			return b
+		}
+	}
+
+	return (*mBucket)(atomic.LoadPointer(&n.buckets[i]))
+}
+
+func (n *mNode) initBuckets() {
+	for i := range n.buckets {
+		n.initBucket(uint32(i))
+	}
+	atomic.StorePointer(&n.pred, nil)
+}
+
+// Cache is a 'cache map'.
+type Cache struct {
+	mu     sync.RWMutex
+	mHead  unsafe.Pointer // *mNode
+	nodes  int32
+	size   int32
+	cacher Cacher
+	closed bool
+}
+
+// NewCache creates a new 'cache map'. The cacher is optional and
+// may be nil.
+func NewCache(cacher Cacher) *Cache {
+	h := &mNode{
+		buckets:         make([]unsafe.Pointer, mInitialSize),
+		mask:            mInitialSize - 1,
+		growThreshold:   int32(mInitialSize * mOverflowThreshold),
+		shrinkThreshold: 0,
+	}
+	for i := range h.buckets {
+		h.buckets[i] = unsafe.Pointer(&mBucket{})
+	}
+	r := &Cache{
+		mHead:  unsafe.Pointer(h),
+		cacher: cacher,
+	}
+	return r
+}
+
+func (r *Cache) getBucket(hash uint32) (*mNode, *mBucket) {
+	h := (*mNode)(atomic.LoadPointer(&r.mHead))
+	i := hash & h.mask
+	b := (*mBucket)(atomic.LoadPointer(&h.buckets[i]))
+	if b == nil {
+		b = h.initBucket(i)
+	}
+	return h, b
+}
+
+func (r *Cache) delete(n *Node) bool {
+	for {
+		h, b := r.getBucket(n.hash)
+		done, deleted := b.delete(r, h, n.hash, n.ns, n.key)
+		if done {
+			return deleted
+		}
+	}
+}
+
+// Nodes returns number of 'cache node' in the map.
+func (r *Cache) Nodes() int {
+	return int(atomic.LoadInt32(&r.nodes))
+}
+
+// Size returns sums of 'cache node' size in the map.
+func (r *Cache) Size() int {
+	return int(atomic.LoadInt32(&r.size))
+}
+
+// Capacity returns cache capacity.
+func (r *Cache) Capacity() int {
+	if r.cacher == nil {
+		return 0
+	}
+	return r.cacher.Capacity()
+}
+
+// SetCapacity sets cache capacity.
+func (r *Cache) SetCapacity(capacity int) {
+	if r.cacher != nil {
+		r.cacher.SetCapacity(capacity)
+	}
+}
+
+// Get gets 'cache node' with the given namespace and key.
+// If cache node is not found and setFunc is not nil, Get will atomically creates
+// the 'cache node' by calling setFunc. Otherwise Get will returns nil.
+//
+// The returned 'cache handle' should be released after use by calling Release
+// method.
+func (r *Cache) Get(ns, key uint64, setFunc func() (size int, value Value)) *Handle {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return nil
+	}
+
+	hash := murmur32(ns, key, 0xf00)
+	for {
+		h, b := r.getBucket(hash)
+		done, _, n := b.get(r, h, hash, ns, key, setFunc == nil)
+		if done {
+			if n != nil {
+				n.mu.Lock()
+				if n.value == nil {
+					if setFunc == nil {
+						n.mu.Unlock()
+						n.unref()
+						return nil
+					}
+
+					n.size, n.value = setFunc()
+					if n.value == nil {
+						n.size = 0
+						n.mu.Unlock()
+						n.unref()
+						return nil
+					}
+					atomic.AddInt32(&r.size, int32(n.size))
+				}
+				n.mu.Unlock()
+				if r.cacher != nil {
+					r.cacher.Promote(n)
+				}
+				return &Handle{unsafe.Pointer(n)}
+			}
+
+			break
+		}
+	}
+	return nil
+}
+
+// Delete removes and ban 'cache node' with the given namespace and key.
+// A banned 'cache node' will never inserted into the 'cache tree'. Ban
+// only attributed to the particular 'cache node', so when a 'cache node'
+// is recreated it will not be banned.
+//
+// If onDel is not nil, then it will be executed if such 'cache node'
+// doesn't exist or once the 'cache node' is released.
+//
+// Delete return true is such 'cache node' exist.
+func (r *Cache) Delete(ns, key uint64, onDel func()) bool {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return false
+	}
+
+	hash := murmur32(ns, key, 0xf00)
+	for {
+		h, b := r.getBucket(hash)
+		done, _, n := b.get(r, h, hash, ns, key, true)
+		if done {
+			if n != nil {
+				if onDel != nil {
+					n.mu.Lock()
+					n.onDel = append(n.onDel, onDel)
+					n.mu.Unlock()
+				}
+				if r.cacher != nil {
+					r.cacher.Ban(n)
+				}
+				n.unref()
+				return true
+			}
+
+			break
+		}
+	}
+
+	if onDel != nil {
+		onDel()
+	}
+
+	return false
+}
+
+// Evict evicts 'cache node' with the given namespace and key. This will
+// simply call Cacher.Evict.
+//
+// Evict return true is such 'cache node' exist.
+func (r *Cache) Evict(ns, key uint64) bool {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return false
+	}
+
+	hash := murmur32(ns, key, 0xf00)
+	for {
+		h, b := r.getBucket(hash)
+		done, _, n := b.get(r, h, hash, ns, key, true)
+		if done {
+			if n != nil {
+				if r.cacher != nil {
+					r.cacher.Evict(n)
+				}
+				n.unref()
+				return true
+			}
+
+			break
+		}
+	}
+
+	return false
+}
+
+// EvictNS evicts 'cache node' with the given namespace. This will
+// simply call Cacher.EvictNS.
+func (r *Cache) EvictNS(ns uint64) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return
+	}
+
+	if r.cacher != nil {
+		r.cacher.EvictNS(ns)
+	}
+}
+
+// EvictAll evicts all 'cache node'. This will simply call Cacher.EvictAll.
+func (r *Cache) EvictAll() {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	if r.closed {
+		return
+	}
+
+	if r.cacher != nil {
+		r.cacher.EvictAll()
+	}
+}
+
+// Close closes the 'cache map' and forcefully releases all 'cache node'.
+func (r *Cache) Close() error {
+	r.mu.Lock()
+	if !r.closed {
+		r.closed = true
+
+		h := (*mNode)(r.mHead)
+		h.initBuckets()
+
+		for i := range h.buckets {
+			b := (*mBucket)(h.buckets[i])
+			for _, n := range b.node {
+				// Call releaser.
+				if n.value != nil {
+					if r, ok := n.value.(util.Releaser); ok {
+						r.Release()
+					}
+					n.value = nil
+				}
+
+				// Call OnDel.
+				for _, f := range n.onDel {
+					f()
+				}
+				n.onDel = nil
+			}
+		}
+	}
+	r.mu.Unlock()
+
+	// Avoid deadlock.
+	if r.cacher != nil {
+		if err := r.cacher.Close(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// CloseWeak closes the 'cache map' and evict all 'cache node' from cacher, but
+// unlike Close it doesn't forcefully releases 'cache node'.
+func (r *Cache) CloseWeak() error {
+	r.mu.Lock()
+	if !r.closed {
+		r.closed = true
+	}
+	r.mu.Unlock()
+
+	// Avoid deadlock.
+	if r.cacher != nil {
+		r.cacher.EvictAll()
+		if err := r.cacher.Close(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Node is a 'cache node'.
+type Node struct {
+	r *Cache
+
+	hash    uint32
+	ns, key uint64
+
+	mu    sync.Mutex
+	size  int
+	value Value
+
+	ref   int32
+	onDel []func()
+
+	CacheData unsafe.Pointer
+}
+
+// NS returns this 'cache node' namespace.
+func (n *Node) NS() uint64 {
+	return n.ns
+}
+
+// Key returns this 'cache node' key.
+func (n *Node) Key() uint64 {
+	return n.key
+}
+
+// Size returns this 'cache node' size.
+func (n *Node) Size() int {
+	return n.size
+}
+
+// Value returns this 'cache node' value.
+func (n *Node) Value() Value {
+	return n.value
+}
+
+// Ref returns this 'cache node' ref counter.
+func (n *Node) Ref() int32 {
+	return atomic.LoadInt32(&n.ref)
+}
+
+// GetHandle returns an handle for this 'cache node'.
+func (n *Node) GetHandle() *Handle {
+	if atomic.AddInt32(&n.ref, 1) <= 1 {
+		panic("BUG: Node.GetHandle on zero ref")
+	}
+	return &Handle{unsafe.Pointer(n)}
+}
+
+func (n *Node) unref() {
+	if atomic.AddInt32(&n.ref, -1) == 0 {
+		n.r.delete(n)
+	}
+}
+
+func (n *Node) unrefLocked() {
+	if atomic.AddInt32(&n.ref, -1) == 0 {
+		n.r.mu.RLock()
+		if !n.r.closed {
+			n.r.delete(n)
+		}
+		n.r.mu.RUnlock()
+	}
+}
+
+// Handle is a 'cache handle' of a 'cache node'.
+type Handle struct {
+	n unsafe.Pointer // *Node
+}
+
+// Value returns the value of the 'cache node'.
+func (h *Handle) Value() Value {
+	n := (*Node)(atomic.LoadPointer(&h.n))
+	if n != nil {
+		return n.value
+	}
+	return nil
+}
+
+// Release releases this 'cache handle'.
+// It is safe to call release multiple times.
+func (h *Handle) Release() {
+	nPtr := atomic.LoadPointer(&h.n)
+	if nPtr != nil && atomic.CompareAndSwapPointer(&h.n, nPtr, nil) {
+		n := (*Node)(nPtr)
+		n.unrefLocked()
+	}
+}
+
+func murmur32(ns, key uint64, seed uint32) uint32 {
+	const (
+		m = uint32(0x5bd1e995)
+		r = 24
+	)
+
+	k1 := uint32(ns >> 32)
+	k2 := uint32(ns)
+	k3 := uint32(key >> 32)
+	k4 := uint32(key)
+
+	k1 *= m
+	k1 ^= k1 >> r
+	k1 *= m
+
+	k2 *= m
+	k2 ^= k2 >> r
+	k2 *= m
+
+	k3 *= m
+	k3 ^= k3 >> r
+	k3 *= m
+
+	k4 *= m
+	k4 ^= k4 >> r
+	k4 *= m
+
+	h := seed
+
+	h *= m
+	h ^= k1
+	h *= m
+	h ^= k2
+	h *= m
+	h ^= k3
+	h *= m
+	h ^= k4
+
+	h ^= h >> 13
+	h *= m
+	h ^= h >> 15
+
+	return h
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/cache/lru.go b/vendor/github.com/syndtr/goleveldb/leveldb/cache/lru.go
new file mode 100644
index 0000000000..d9a84cde15
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/cache/lru.go
@@ -0,0 +1,195 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package cache
+
+import (
+	"sync"
+	"unsafe"
+)
+
+type lruNode struct {
+	n   *Node
+	h   *Handle
+	ban bool
+
+	next, prev *lruNode
+}
+
+func (n *lruNode) insert(at *lruNode) {
+	x := at.next
+	at.next = n
+	n.prev = at
+	n.next = x
+	x.prev = n
+}
+
+func (n *lruNode) remove() {
+	if n.prev != nil {
+		n.prev.next = n.next
+		n.next.prev = n.prev
+		n.prev = nil
+		n.next = nil
+	} else {
+		panic("BUG: removing removed node")
+	}
+}
+
+type lru struct {
+	mu       sync.Mutex
+	capacity int
+	used     int
+	recent   lruNode
+}
+
+func (r *lru) reset() {
+	r.recent.next = &r.recent
+	r.recent.prev = &r.recent
+	r.used = 0
+}
+
+func (r *lru) Capacity() int {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	return r.capacity
+}
+
+func (r *lru) SetCapacity(capacity int) {
+	var evicted []*lruNode
+
+	r.mu.Lock()
+	r.capacity = capacity
+	for r.used > r.capacity {
+		rn := r.recent.prev
+		if rn == nil {
+			panic("BUG: invalid LRU used or capacity counter")
+		}
+		rn.remove()
+		rn.n.CacheData = nil
+		r.used -= rn.n.Size()
+		evicted = append(evicted, rn)
+	}
+	r.mu.Unlock()
+
+	for _, rn := range evicted {
+		rn.h.Release()
+	}
+}
+
+func (r *lru) Promote(n *Node) {
+	var evicted []*lruNode
+
+	r.mu.Lock()
+	if n.CacheData == nil {
+		if n.Size() <= r.capacity {
+			rn := &lruNode{n: n, h: n.GetHandle()}
+			rn.insert(&r.recent)
+			n.CacheData = unsafe.Pointer(rn)
+			r.used += n.Size()
+
+			for r.used > r.capacity {
+				rn := r.recent.prev
+				if rn == nil {
+					panic("BUG: invalid LRU used or capacity counter")
+				}
+				rn.remove()
+				rn.n.CacheData = nil
+				r.used -= rn.n.Size()
+				evicted = append(evicted, rn)
+			}
+		}
+	} else {
+		rn := (*lruNode)(n.CacheData)
+		if !rn.ban {
+			rn.remove()
+			rn.insert(&r.recent)
+		}
+	}
+	r.mu.Unlock()
+
+	for _, rn := range evicted {
+		rn.h.Release()
+	}
+}
+
+func (r *lru) Ban(n *Node) {
+	r.mu.Lock()
+	if n.CacheData == nil {
+		n.CacheData = unsafe.Pointer(&lruNode{n: n, ban: true})
+	} else {
+		rn := (*lruNode)(n.CacheData)
+		if !rn.ban {
+			rn.remove()
+			rn.ban = true
+			r.used -= rn.n.Size()
+			r.mu.Unlock()
+
+			rn.h.Release()
+			rn.h = nil
+			return
+		}
+	}
+	r.mu.Unlock()
+}
+
+func (r *lru) Evict(n *Node) {
+	r.mu.Lock()
+	rn := (*lruNode)(n.CacheData)
+	if rn == nil || rn.ban {
+		r.mu.Unlock()
+		return
+	}
+	n.CacheData = nil
+	r.mu.Unlock()
+
+	rn.h.Release()
+}
+
+func (r *lru) EvictNS(ns uint64) {
+	var evicted []*lruNode
+
+	r.mu.Lock()
+	for e := r.recent.prev; e != &r.recent; {
+		rn := e
+		e = e.prev
+		if rn.n.NS() == ns {
+			rn.remove()
+			rn.n.CacheData = nil
+			r.used -= rn.n.Size()
+			evicted = append(evicted, rn)
+		}
+	}
+	r.mu.Unlock()
+
+	for _, rn := range evicted {
+		rn.h.Release()
+	}
+}
+
+func (r *lru) EvictAll() {
+	r.mu.Lock()
+	back := r.recent.prev
+	for rn := back; rn != &r.recent; rn = rn.prev {
+		rn.n.CacheData = nil
+	}
+	r.reset()
+	r.mu.Unlock()
+
+	for rn := back; rn != &r.recent; rn = rn.prev {
+		rn.h.Release()
+	}
+}
+
+func (r *lru) Close() error {
+	return nil
+}
+
+// NewLRU create a new LRU-cache.
+func NewLRU(capacity int) Cacher {
+	r := &lru{capacity: capacity}
+	r.reset()
+	return r
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/comparer.go b/vendor/github.com/syndtr/goleveldb/leveldb/comparer.go
new file mode 100644
index 0000000000..448402b826
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/comparer.go
@@ -0,0 +1,67 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/comparer"
+)
+
+type iComparer struct {
+	ucmp comparer.Comparer
+}
+
+func (icmp *iComparer) uName() string {
+	return icmp.ucmp.Name()
+}
+
+func (icmp *iComparer) uCompare(a, b []byte) int {
+	return icmp.ucmp.Compare(a, b)
+}
+
+func (icmp *iComparer) uSeparator(dst, a, b []byte) []byte {
+	return icmp.ucmp.Separator(dst, a, b)
+}
+
+func (icmp *iComparer) uSuccessor(dst, b []byte) []byte {
+	return icmp.ucmp.Successor(dst, b)
+}
+
+func (icmp *iComparer) Name() string {
+	return icmp.uName()
+}
+
+func (icmp *iComparer) Compare(a, b []byte) int {
+	x := icmp.uCompare(internalKey(a).ukey(), internalKey(b).ukey())
+	if x == 0 {
+		if m, n := internalKey(a).num(), internalKey(b).num(); m > n {
+			return -1
+		} else if m < n {
+			return 1
+		}
+	}
+	return x
+}
+
+func (icmp *iComparer) Separator(dst, a, b []byte) []byte {
+	ua, ub := internalKey(a).ukey(), internalKey(b).ukey()
+	dst = icmp.uSeparator(dst, ua, ub)
+	if dst != nil && len(dst) < len(ua) && icmp.uCompare(ua, dst) < 0 {
+		// Append earliest possible number.
+		return append(dst, keyMaxNumBytes...)
+	}
+	return nil
+}
+
+func (icmp *iComparer) Successor(dst, b []byte) []byte {
+	ub := internalKey(b).ukey()
+	dst = icmp.uSuccessor(dst, ub)
+	if dst != nil && len(dst) < len(ub) && icmp.uCompare(ub, dst) < 0 {
+		// Append earliest possible number.
+		return append(dst, keyMaxNumBytes...)
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/comparer/bytes_comparer.go b/vendor/github.com/syndtr/goleveldb/leveldb/comparer/bytes_comparer.go
new file mode 100644
index 0000000000..abf9fb65c7
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/comparer/bytes_comparer.go
@@ -0,0 +1,51 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package comparer
+
+import "bytes"
+
+type bytesComparer struct{}
+
+func (bytesComparer) Compare(a, b []byte) int {
+	return bytes.Compare(a, b)
+}
+
+func (bytesComparer) Name() string {
+	return "leveldb.BytewiseComparator"
+}
+
+func (bytesComparer) Separator(dst, a, b []byte) []byte {
+	i, n := 0, len(a)
+	if n > len(b) {
+		n = len(b)
+	}
+	for ; i < n && a[i] == b[i]; i++ {
+	}
+	if i >= n {
+		// Do not shorten if one string is a prefix of the other
+	} else if c := a[i]; c < 0xff && c+1 < b[i] {
+		dst = append(dst, a[:i+1]...)
+		dst[len(dst)-1]++
+		return dst
+	}
+	return nil
+}
+
+func (bytesComparer) Successor(dst, b []byte) []byte {
+	for i, c := range b {
+		if c != 0xff {
+			dst = append(dst, b[:i+1]...)
+			dst[len(dst)-1]++
+			return dst
+		}
+	}
+	return nil
+}
+
+// DefaultComparer are default implementation of the Comparer interface.
+// It uses the natural ordering, consistent with bytes.Compare.
+var DefaultComparer = bytesComparer{}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/comparer/comparer.go b/vendor/github.com/syndtr/goleveldb/leveldb/comparer/comparer.go
new file mode 100644
index 0000000000..2c522db23b
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/comparer/comparer.go
@@ -0,0 +1,57 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package comparer provides interface and implementation for ordering
+// sets of data.
+package comparer
+
+// BasicComparer is the interface that wraps the basic Compare method.
+type BasicComparer interface {
+	// Compare returns -1, 0, or +1 depending on whether a is 'less than',
+	// 'equal to' or 'greater than' b. The two arguments can only be 'equal'
+	// if their contents are exactly equal. Furthermore, the empty slice
+	// must be 'less than' any non-empty slice.
+	Compare(a, b []byte) int
+}
+
+// Comparer defines a total ordering over the space of []byte keys: a 'less
+// than' relationship.
+type Comparer interface {
+	BasicComparer
+
+	// Name returns name of the comparer.
+	//
+	// The Level-DB on-disk format stores the comparer name, and opening a
+	// database with a different comparer from the one it was created with
+	// will result in an error.
+	//
+	// An implementation to a new name whenever the comparer implementation
+	// changes in a way that will cause the relative ordering of any two keys
+	// to change.
+	//
+	// Names starting with "leveldb." are reserved and should not be used
+	// by any users of this package.
+	Name() string
+
+	// Bellow are advanced functions used to reduce the space requirements
+	// for internal data structures such as index blocks.
+
+	// Separator appends a sequence of bytes x to dst such that a <= x && x < b,
+	// where 'less than' is consistent with Compare. An implementation should
+	// return nil if x equal to a.
+	//
+	// Either contents of a or b should not by any means modified. Doing so
+	// may cause corruption on the internal state.
+	Separator(dst, a, b []byte) []byte
+
+	// Successor appends a sequence of bytes x to dst such that x >= b, where
+	// 'less than' is consistent with Compare. An implementation should return
+	// nil if x equal to b.
+	//
+	// Contents of b should not by any means modified. Doing so may cause
+	// corruption on the internal state.
+	Successor(dst, b []byte) []byte
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db.go b/vendor/github.com/syndtr/goleveldb/leveldb/db.go
new file mode 100644
index 0000000000..b27c38d37e
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db.go
@@ -0,0 +1,1175 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"container/list"
+	"fmt"
+	"io"
+	"os"
+	"runtime"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/journal"
+	"github.com/syndtr/goleveldb/leveldb/memdb"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"github.com/syndtr/goleveldb/leveldb/table"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// DB is a LevelDB database.
+type DB struct {
+	// Need 64-bit alignment.
+	seq uint64
+
+	// Stats. Need 64-bit alignment.
+	cWriteDelay            int64 // The cumulative duration of write delays
+	cWriteDelayN           int32 // The cumulative number of write delays
+	inWritePaused          int32 // The indicator whether write operation is paused by compaction
+	aliveSnaps, aliveIters int32
+
+	// Session.
+	s *session
+
+	// MemDB.
+	memMu           sync.RWMutex
+	memPool         chan *memdb.DB
+	mem, frozenMem  *memDB
+	journal         *journal.Writer
+	journalWriter   storage.Writer
+	journalFd       storage.FileDesc
+	frozenJournalFd storage.FileDesc
+	frozenSeq       uint64
+
+	// Snapshot.
+	snapsMu   sync.Mutex
+	snapsList *list.List
+
+	// Write.
+	batchPool    sync.Pool
+	writeMergeC  chan writeMerge
+	writeMergedC chan bool
+	writeLockC   chan struct{}
+	writeAckC    chan error
+	writeDelay   time.Duration
+	writeDelayN  int
+	tr           *Transaction
+
+	// Compaction.
+	compCommitLk     sync.Mutex
+	tcompCmdC        chan cCmd
+	tcompPauseC      chan chan<- struct{}
+	mcompCmdC        chan cCmd
+	compErrC         chan error
+	compPerErrC      chan error
+	compErrSetC      chan error
+	compWriteLocking bool
+	compStats        cStats
+	memdbMaxLevel    int // For testing.
+
+	// Close.
+	closeW sync.WaitGroup
+	closeC chan struct{}
+	closed uint32
+	closer io.Closer
+}
+
+func openDB(s *session) (*DB, error) {
+	s.log("db@open opening")
+	start := time.Now()
+	db := &DB{
+		s: s,
+		// Initial sequence
+		seq: s.stSeqNum,
+		// MemDB
+		memPool: make(chan *memdb.DB, 1),
+		// Snapshot
+		snapsList: list.New(),
+		// Write
+		batchPool:    sync.Pool{New: newBatch},
+		writeMergeC:  make(chan writeMerge),
+		writeMergedC: make(chan bool),
+		writeLockC:   make(chan struct{}, 1),
+		writeAckC:    make(chan error),
+		// Compaction
+		tcompCmdC:   make(chan cCmd),
+		tcompPauseC: make(chan chan<- struct{}),
+		mcompCmdC:   make(chan cCmd),
+		compErrC:    make(chan error),
+		compPerErrC: make(chan error),
+		compErrSetC: make(chan error),
+		// Close
+		closeC: make(chan struct{}),
+	}
+
+	// Read-only mode.
+	readOnly := s.o.GetReadOnly()
+
+	if readOnly {
+		// Recover journals (read-only mode).
+		if err := db.recoverJournalRO(); err != nil {
+			return nil, err
+		}
+	} else {
+		// Recover journals.
+		if err := db.recoverJournal(); err != nil {
+			return nil, err
+		}
+
+		// Remove any obsolete files.
+		if err := db.checkAndCleanFiles(); err != nil {
+			// Close journal.
+			if db.journal != nil {
+				db.journal.Close()
+				db.journalWriter.Close()
+			}
+			return nil, err
+		}
+
+	}
+
+	// Doesn't need to be included in the wait group.
+	go db.compactionError()
+	go db.mpoolDrain()
+
+	if readOnly {
+		db.SetReadOnly()
+	} else {
+		db.closeW.Add(2)
+		go db.tCompaction()
+		go db.mCompaction()
+		// go db.jWriter()
+	}
+
+	s.logf("db@open done T·%v", time.Since(start))
+
+	runtime.SetFinalizer(db, (*DB).Close)
+	return db, nil
+}
+
+// Open opens or creates a DB for the given storage.
+// The DB will be created if not exist, unless ErrorIfMissing is true.
+// Also, if ErrorIfExist is true and the DB exist Open will returns
+// os.ErrExist error.
+//
+// Open will return an error with type of ErrCorrupted if corruption
+// detected in the DB. Use errors.IsCorrupted to test whether an error is
+// due to corruption. Corrupted DB can be recovered with Recover function.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func Open(stor storage.Storage, o *opt.Options) (db *DB, err error) {
+	s, err := newSession(stor, o)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err != nil {
+			s.close()
+			s.release()
+		}
+	}()
+
+	err = s.recover()
+	if err != nil {
+		if !os.IsNotExist(err) || s.o.GetErrorIfMissing() || s.o.GetReadOnly() {
+			return
+		}
+		err = s.create()
+		if err != nil {
+			return
+		}
+	} else if s.o.GetErrorIfExist() {
+		err = os.ErrExist
+		return
+	}
+
+	return openDB(s)
+}
+
+// OpenFile opens or creates a DB for the given path.
+// The DB will be created if not exist, unless ErrorIfMissing is true.
+// Also, if ErrorIfExist is true and the DB exist OpenFile will returns
+// os.ErrExist error.
+//
+// OpenFile uses standard file-system backed storage implementation as
+// described in the leveldb/storage package.
+//
+// OpenFile will return an error with type of ErrCorrupted if corruption
+// detected in the DB. Use errors.IsCorrupted to test whether an error is
+// due to corruption. Corrupted DB can be recovered with Recover function.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func OpenFile(path string, o *opt.Options) (db *DB, err error) {
+	stor, err := storage.OpenFile(path, o.GetReadOnly())
+	if err != nil {
+		return
+	}
+	db, err = Open(stor, o)
+	if err != nil {
+		stor.Close()
+	} else {
+		db.closer = stor
+	}
+	return
+}
+
+// Recover recovers and opens a DB with missing or corrupted manifest files
+// for the given storage. It will ignore any manifest files, valid or not.
+// The DB must already exist or it will returns an error.
+// Also, Recover will ignore ErrorIfMissing and ErrorIfExist options.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func Recover(stor storage.Storage, o *opt.Options) (db *DB, err error) {
+	s, err := newSession(stor, o)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err != nil {
+			s.close()
+			s.release()
+		}
+	}()
+
+	err = recoverTable(s, o)
+	if err != nil {
+		return
+	}
+	return openDB(s)
+}
+
+// RecoverFile recovers and opens a DB with missing or corrupted manifest files
+// for the given path. It will ignore any manifest files, valid or not.
+// The DB must already exist or it will returns an error.
+// Also, Recover will ignore ErrorIfMissing and ErrorIfExist options.
+//
+// RecoverFile uses standard file-system backed storage implementation as described
+// in the leveldb/storage package.
+//
+// The returned DB instance is safe for concurrent use.
+// The DB must be closed after use, by calling Close method.
+func RecoverFile(path string, o *opt.Options) (db *DB, err error) {
+	stor, err := storage.OpenFile(path, false)
+	if err != nil {
+		return
+	}
+	db, err = Recover(stor, o)
+	if err != nil {
+		stor.Close()
+	} else {
+		db.closer = stor
+	}
+	return
+}
+
+func recoverTable(s *session, o *opt.Options) error {
+	o = dupOptions(o)
+	// Mask StrictReader, lets StrictRecovery doing its job.
+	o.Strict &= ^opt.StrictReader
+
+	// Get all tables and sort it by file number.
+	fds, err := s.stor.List(storage.TypeTable)
+	if err != nil {
+		return err
+	}
+	sortFds(fds)
+
+	var (
+		maxSeq                                                            uint64
+		recoveredKey, goodKey, corruptedKey, corruptedBlock, droppedTable int
+
+		// We will drop corrupted table.
+		strict = o.GetStrict(opt.StrictRecovery)
+		noSync = o.GetNoSync()
+
+		rec   = &sessionRecord{}
+		bpool = util.NewBufferPool(o.GetBlockSize() + 5)
+	)
+	buildTable := func(iter iterator.Iterator) (tmpFd storage.FileDesc, size int64, err error) {
+		tmpFd = s.newTemp()
+		writer, err := s.stor.Create(tmpFd)
+		if err != nil {
+			return
+		}
+		defer func() {
+			writer.Close()
+			if err != nil {
+				s.stor.Remove(tmpFd)
+				tmpFd = storage.FileDesc{}
+			}
+		}()
+
+		// Copy entries.
+		tw := table.NewWriter(writer, o)
+		for iter.Next() {
+			key := iter.Key()
+			if validInternalKey(key) {
+				err = tw.Append(key, iter.Value())
+				if err != nil {
+					return
+				}
+			}
+		}
+		err = iter.Error()
+		if err != nil && !errors.IsCorrupted(err) {
+			return
+		}
+		err = tw.Close()
+		if err != nil {
+			return
+		}
+		if !noSync {
+			err = writer.Sync()
+			if err != nil {
+				return
+			}
+		}
+		size = int64(tw.BytesLen())
+		return
+	}
+	recoverTable := func(fd storage.FileDesc) error {
+		s.logf("table@recovery recovering @%d", fd.Num)
+		reader, err := s.stor.Open(fd)
+		if err != nil {
+			return err
+		}
+		var closed bool
+		defer func() {
+			if !closed {
+				reader.Close()
+			}
+		}()
+
+		// Get file size.
+		size, err := reader.Seek(0, 2)
+		if err != nil {
+			return err
+		}
+
+		var (
+			tSeq                                     uint64
+			tgoodKey, tcorruptedKey, tcorruptedBlock int
+			imin, imax                               []byte
+		)
+		tr, err := table.NewReader(reader, size, fd, nil, bpool, o)
+		if err != nil {
+			return err
+		}
+		iter := tr.NewIterator(nil, nil)
+		if itererr, ok := iter.(iterator.ErrorCallbackSetter); ok {
+			itererr.SetErrorCallback(func(err error) {
+				if errors.IsCorrupted(err) {
+					s.logf("table@recovery block corruption @%d %q", fd.Num, err)
+					tcorruptedBlock++
+				}
+			})
+		}
+
+		// Scan the table.
+		for iter.Next() {
+			key := iter.Key()
+			_, seq, _, kerr := parseInternalKey(key)
+			if kerr != nil {
+				tcorruptedKey++
+				continue
+			}
+			tgoodKey++
+			if seq > tSeq {
+				tSeq = seq
+			}
+			if imin == nil {
+				imin = append([]byte{}, key...)
+			}
+			imax = append(imax[:0], key...)
+		}
+		if err := iter.Error(); err != nil && !errors.IsCorrupted(err) {
+			iter.Release()
+			return err
+		}
+		iter.Release()
+
+		goodKey += tgoodKey
+		corruptedKey += tcorruptedKey
+		corruptedBlock += tcorruptedBlock
+
+		if strict && (tcorruptedKey > 0 || tcorruptedBlock > 0) {
+			droppedTable++
+			s.logf("table@recovery dropped @%d Gk·%d Ck·%d Cb·%d S·%d Q·%d", fd.Num, tgoodKey, tcorruptedKey, tcorruptedBlock, size, tSeq)
+			return nil
+		}
+
+		if tgoodKey > 0 {
+			if tcorruptedKey > 0 || tcorruptedBlock > 0 {
+				// Rebuild the table.
+				s.logf("table@recovery rebuilding @%d", fd.Num)
+				iter := tr.NewIterator(nil, nil)
+				tmpFd, newSize, err := buildTable(iter)
+				iter.Release()
+				if err != nil {
+					return err
+				}
+				closed = true
+				reader.Close()
+				if err := s.stor.Rename(tmpFd, fd); err != nil {
+					return err
+				}
+				size = newSize
+			}
+			if tSeq > maxSeq {
+				maxSeq = tSeq
+			}
+			recoveredKey += tgoodKey
+			// Add table to level 0.
+			rec.addTable(0, fd.Num, size, imin, imax)
+			s.logf("table@recovery recovered @%d Gk·%d Ck·%d Cb·%d S·%d Q·%d", fd.Num, tgoodKey, tcorruptedKey, tcorruptedBlock, size, tSeq)
+		} else {
+			droppedTable++
+			s.logf("table@recovery unrecoverable @%d Ck·%d Cb·%d S·%d", fd.Num, tcorruptedKey, tcorruptedBlock, size)
+		}
+
+		return nil
+	}
+
+	// Recover all tables.
+	if len(fds) > 0 {
+		s.logf("table@recovery F·%d", len(fds))
+
+		// Mark file number as used.
+		s.markFileNum(fds[len(fds)-1].Num)
+
+		for _, fd := range fds {
+			if err := recoverTable(fd); err != nil {
+				return err
+			}
+		}
+
+		s.logf("table@recovery recovered F·%d N·%d Gk·%d Ck·%d Q·%d", len(fds), recoveredKey, goodKey, corruptedKey, maxSeq)
+	}
+
+	// Set sequence number.
+	rec.setSeqNum(maxSeq)
+
+	// Create new manifest.
+	if err := s.create(); err != nil {
+		return err
+	}
+
+	// Commit.
+	return s.commit(rec)
+}
+
+func (db *DB) recoverJournal() error {
+	// Get all journals and sort it by file number.
+	rawFds, err := db.s.stor.List(storage.TypeJournal)
+	if err != nil {
+		return err
+	}
+	sortFds(rawFds)
+
+	// Journals that will be recovered.
+	var fds []storage.FileDesc
+	for _, fd := range rawFds {
+		if fd.Num >= db.s.stJournalNum || fd.Num == db.s.stPrevJournalNum {
+			fds = append(fds, fd)
+		}
+	}
+
+	var (
+		ofd storage.FileDesc // Obsolete file.
+		rec = &sessionRecord{}
+	)
+
+	// Recover journals.
+	if len(fds) > 0 {
+		db.logf("journal@recovery F·%d", len(fds))
+
+		// Mark file number as used.
+		db.s.markFileNum(fds[len(fds)-1].Num)
+
+		var (
+			// Options.
+			strict      = db.s.o.GetStrict(opt.StrictJournal)
+			checksum    = db.s.o.GetStrict(opt.StrictJournalChecksum)
+			writeBuffer = db.s.o.GetWriteBuffer()
+
+			jr       *journal.Reader
+			mdb      = memdb.New(db.s.icmp, writeBuffer)
+			buf      = &util.Buffer{}
+			batchSeq uint64
+			batchLen int
+		)
+
+		for _, fd := range fds {
+			db.logf("journal@recovery recovering @%d", fd.Num)
+
+			fr, err := db.s.stor.Open(fd)
+			if err != nil {
+				return err
+			}
+
+			// Create or reset journal reader instance.
+			if jr == nil {
+				jr = journal.NewReader(fr, dropper{db.s, fd}, strict, checksum)
+			} else {
+				jr.Reset(fr, dropper{db.s, fd}, strict, checksum)
+			}
+
+			// Flush memdb and remove obsolete journal file.
+			if !ofd.Zero() {
+				if mdb.Len() > 0 {
+					if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
+						fr.Close()
+						return err
+					}
+				}
+
+				rec.setJournalNum(fd.Num)
+				rec.setSeqNum(db.seq)
+				if err := db.s.commit(rec); err != nil {
+					fr.Close()
+					return err
+				}
+				rec.resetAddedTables()
+
+				db.s.stor.Remove(ofd)
+				ofd = storage.FileDesc{}
+			}
+
+			// Replay journal to memdb.
+			mdb.Reset()
+			for {
+				r, err := jr.Next()
+				if err != nil {
+					if err == io.EOF {
+						break
+					}
+
+					fr.Close()
+					return errors.SetFd(err, fd)
+				}
+
+				buf.Reset()
+				if _, err := buf.ReadFrom(r); err != nil {
+					if err == io.ErrUnexpectedEOF {
+						// This is error returned due to corruption, with strict == false.
+						continue
+					}
+
+					fr.Close()
+					return errors.SetFd(err, fd)
+				}
+				batchSeq, batchLen, err = decodeBatchToMem(buf.Bytes(), db.seq, mdb)
+				if err != nil {
+					if !strict && errors.IsCorrupted(err) {
+						db.s.logf("journal error: %v (skipped)", err)
+						// We won't apply sequence number as it might be corrupted.
+						continue
+					}
+
+					fr.Close()
+					return errors.SetFd(err, fd)
+				}
+
+				// Save sequence number.
+				db.seq = batchSeq + uint64(batchLen)
+
+				// Flush it if large enough.
+				if mdb.Size() >= writeBuffer {
+					if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
+						fr.Close()
+						return err
+					}
+
+					mdb.Reset()
+				}
+			}
+
+			fr.Close()
+			ofd = fd
+		}
+
+		// Flush the last memdb.
+		if mdb.Len() > 0 {
+			if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
+				return err
+			}
+		}
+	}
+
+	// Create a new journal.
+	if _, err := db.newMem(0); err != nil {
+		return err
+	}
+
+	// Commit.
+	rec.setJournalNum(db.journalFd.Num)
+	rec.setSeqNum(db.seq)
+	if err := db.s.commit(rec); err != nil {
+		// Close journal on error.
+		if db.journal != nil {
+			db.journal.Close()
+			db.journalWriter.Close()
+		}
+		return err
+	}
+
+	// Remove the last obsolete journal file.
+	if !ofd.Zero() {
+		db.s.stor.Remove(ofd)
+	}
+
+	return nil
+}
+
+func (db *DB) recoverJournalRO() error {
+	// Get all journals and sort it by file number.
+	rawFds, err := db.s.stor.List(storage.TypeJournal)
+	if err != nil {
+		return err
+	}
+	sortFds(rawFds)
+
+	// Journals that will be recovered.
+	var fds []storage.FileDesc
+	for _, fd := range rawFds {
+		if fd.Num >= db.s.stJournalNum || fd.Num == db.s.stPrevJournalNum {
+			fds = append(fds, fd)
+		}
+	}
+
+	var (
+		// Options.
+		strict      = db.s.o.GetStrict(opt.StrictJournal)
+		checksum    = db.s.o.GetStrict(opt.StrictJournalChecksum)
+		writeBuffer = db.s.o.GetWriteBuffer()
+
+		mdb = memdb.New(db.s.icmp, writeBuffer)
+	)
+
+	// Recover journals.
+	if len(fds) > 0 {
+		db.logf("journal@recovery RO·Mode F·%d", len(fds))
+
+		var (
+			jr       *journal.Reader
+			buf      = &util.Buffer{}
+			batchSeq uint64
+			batchLen int
+		)
+
+		for _, fd := range fds {
+			db.logf("journal@recovery recovering @%d", fd.Num)
+
+			fr, err := db.s.stor.Open(fd)
+			if err != nil {
+				return err
+			}
+
+			// Create or reset journal reader instance.
+			if jr == nil {
+				jr = journal.NewReader(fr, dropper{db.s, fd}, strict, checksum)
+			} else {
+				jr.Reset(fr, dropper{db.s, fd}, strict, checksum)
+			}
+
+			// Replay journal to memdb.
+			for {
+				r, err := jr.Next()
+				if err != nil {
+					if err == io.EOF {
+						break
+					}
+
+					fr.Close()
+					return errors.SetFd(err, fd)
+				}
+
+				buf.Reset()
+				if _, err := buf.ReadFrom(r); err != nil {
+					if err == io.ErrUnexpectedEOF {
+						// This is error returned due to corruption, with strict == false.
+						continue
+					}
+
+					fr.Close()
+					return errors.SetFd(err, fd)
+				}
+				batchSeq, batchLen, err = decodeBatchToMem(buf.Bytes(), db.seq, mdb)
+				if err != nil {
+					if !strict && errors.IsCorrupted(err) {
+						db.s.logf("journal error: %v (skipped)", err)
+						// We won't apply sequence number as it might be corrupted.
+						continue
+					}
+
+					fr.Close()
+					return errors.SetFd(err, fd)
+				}
+
+				// Save sequence number.
+				db.seq = batchSeq + uint64(batchLen)
+			}
+
+			fr.Close()
+		}
+	}
+
+	// Set memDB.
+	db.mem = &memDB{db: db, DB: mdb, ref: 1}
+
+	return nil
+}
+
+func memGet(mdb *memdb.DB, ikey internalKey, icmp *iComparer) (ok bool, mv []byte, err error) {
+	mk, mv, err := mdb.Find(ikey)
+	if err == nil {
+		ukey, _, kt, kerr := parseInternalKey(mk)
+		if kerr != nil {
+			// Shouldn't have had happen.
+			panic(kerr)
+		}
+		if icmp.uCompare(ukey, ikey.ukey()) == 0 {
+			if kt == keyTypeDel {
+				return true, nil, ErrNotFound
+			}
+			return true, mv, nil
+
+		}
+	} else if err != ErrNotFound {
+		return true, nil, err
+	}
+	return
+}
+
+func (db *DB) get(auxm *memdb.DB, auxt tFiles, key []byte, seq uint64, ro *opt.ReadOptions) (value []byte, err error) {
+	ikey := makeInternalKey(nil, key, seq, keyTypeSeek)
+
+	if auxm != nil {
+		if ok, mv, me := memGet(auxm, ikey, db.s.icmp); ok {
+			return append([]byte{}, mv...), me
+		}
+	}
+
+	em, fm := db.getMems()
+	for _, m := range [...]*memDB{em, fm} {
+		if m == nil {
+			continue
+		}
+		defer m.decref()
+
+		if ok, mv, me := memGet(m.DB, ikey, db.s.icmp); ok {
+			return append([]byte{}, mv...), me
+		}
+	}
+
+	v := db.s.version()
+	value, cSched, err := v.get(auxt, ikey, ro, false)
+	v.release()
+	if cSched {
+		// Trigger table compaction.
+		db.compTrigger(db.tcompCmdC)
+	}
+	return
+}
+
+func nilIfNotFound(err error) error {
+	if err == ErrNotFound {
+		return nil
+	}
+	return err
+}
+
+func (db *DB) has(auxm *memdb.DB, auxt tFiles, key []byte, seq uint64, ro *opt.ReadOptions) (ret bool, err error) {
+	ikey := makeInternalKey(nil, key, seq, keyTypeSeek)
+
+	if auxm != nil {
+		if ok, _, me := memGet(auxm, ikey, db.s.icmp); ok {
+			return me == nil, nilIfNotFound(me)
+		}
+	}
+
+	em, fm := db.getMems()
+	for _, m := range [...]*memDB{em, fm} {
+		if m == nil {
+			continue
+		}
+		defer m.decref()
+
+		if ok, _, me := memGet(m.DB, ikey, db.s.icmp); ok {
+			return me == nil, nilIfNotFound(me)
+		}
+	}
+
+	v := db.s.version()
+	_, cSched, err := v.get(auxt, ikey, ro, true)
+	v.release()
+	if cSched {
+		// Trigger table compaction.
+		db.compTrigger(db.tcompCmdC)
+	}
+	if err == nil {
+		ret = true
+	} else if err == ErrNotFound {
+		err = nil
+	}
+	return
+}
+
+// Get gets the value for the given key. It returns ErrNotFound if the
+// DB does not contains the key.
+//
+// The returned slice is its own copy, it is safe to modify the contents
+// of the returned slice.
+// It is safe to modify the contents of the argument after Get returns.
+func (db *DB) Get(key []byte, ro *opt.ReadOptions) (value []byte, err error) {
+	err = db.ok()
+	if err != nil {
+		return
+	}
+
+	se := db.acquireSnapshot()
+	defer db.releaseSnapshot(se)
+	return db.get(nil, nil, key, se.seq, ro)
+}
+
+// Has returns true if the DB does contains the given key.
+//
+// It is safe to modify the contents of the argument after Has returns.
+func (db *DB) Has(key []byte, ro *opt.ReadOptions) (ret bool, err error) {
+	err = db.ok()
+	if err != nil {
+		return
+	}
+
+	se := db.acquireSnapshot()
+	defer db.releaseSnapshot(se)
+	return db.has(nil, nil, key, se.seq, ro)
+}
+
+// NewIterator returns an iterator for the latest snapshot of the
+// underlying DB.
+// The returned iterator is not safe for concurrent use, but it is safe to use
+// multiple iterators concurrently, with each in a dedicated goroutine.
+// It is also safe to use an iterator concurrently with modifying its
+// underlying DB. The resultant key/value pairs are guaranteed to be
+// consistent.
+//
+// Slice allows slicing the iterator to only contains keys in the given
+// range. A nil Range.Start is treated as a key before all keys in the
+// DB. And a nil Range.Limit is treated as a key after all keys in
+// the DB.
+//
+// The iterator must be released after use, by calling Release method.
+//
+// Also read Iterator documentation of the leveldb/iterator package.
+func (db *DB) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+	if err := db.ok(); err != nil {
+		return iterator.NewEmptyIterator(err)
+	}
+
+	se := db.acquireSnapshot()
+	defer db.releaseSnapshot(se)
+	// Iterator holds 'version' lock, 'version' is immutable so snapshot
+	// can be released after iterator created.
+	return db.newIterator(nil, nil, se.seq, slice, ro)
+}
+
+// GetSnapshot returns a latest snapshot of the underlying DB. A snapshot
+// is a frozen snapshot of a DB state at a particular point in time. The
+// content of snapshot are guaranteed to be consistent.
+//
+// The snapshot must be released after use, by calling Release method.
+func (db *DB) GetSnapshot() (*Snapshot, error) {
+	if err := db.ok(); err != nil {
+		return nil, err
+	}
+
+	return db.newSnapshot(), nil
+}
+
+// GetProperty returns value of the given property name.
+//
+// Property names:
+//	leveldb.num-files-at-level{n}
+//		Returns the number of files at level 'n'.
+//	leveldb.stats
+//		Returns statistics of the underlying DB.
+//	leveldb.iostats
+//		Returns statistics of effective disk read and write.
+//	leveldb.writedelay
+//		Returns cumulative write delay caused by compaction.
+//	leveldb.sstables
+//		Returns sstables list for each level.
+//	leveldb.blockpool
+//		Returns block pool stats.
+//	leveldb.cachedblock
+//		Returns size of cached block.
+//	leveldb.openedtables
+//		Returns number of opened tables.
+//	leveldb.alivesnaps
+//		Returns number of alive snapshots.
+//	leveldb.aliveiters
+//		Returns number of alive iterators.
+func (db *DB) GetProperty(name string) (value string, err error) {
+	err = db.ok()
+	if err != nil {
+		return
+	}
+
+	const prefix = "leveldb."
+	if !strings.HasPrefix(name, prefix) {
+		return "", ErrNotFound
+	}
+	p := name[len(prefix):]
+
+	v := db.s.version()
+	defer v.release()
+
+	numFilesPrefix := "num-files-at-level"
+	switch {
+	case strings.HasPrefix(p, numFilesPrefix):
+		var level uint
+		var rest string
+		n, _ := fmt.Sscanf(p[len(numFilesPrefix):], "%d%s", &level, &rest)
+		if n != 1 {
+			err = ErrNotFound
+		} else {
+			value = fmt.Sprint(v.tLen(int(level)))
+		}
+	case p == "stats":
+		value = "Compactions\n" +
+			" Level |   Tables   |    Size(MB)   |    Time(sec)  |    Read(MB)   |   Write(MB)\n" +
+			"-------+------------+---------------+---------------+---------------+---------------\n"
+		for level, tables := range v.levels {
+			duration, read, write := db.compStats.getStat(level)
+			if len(tables) == 0 && duration == 0 {
+				continue
+			}
+			value += fmt.Sprintf(" %3d   | %10d | %13.5f | %13.5f | %13.5f | %13.5f\n",
+				level, len(tables), float64(tables.size())/1048576.0, duration.Seconds(),
+				float64(read)/1048576.0, float64(write)/1048576.0)
+		}
+	case p == "iostats":
+		value = fmt.Sprintf("Read(MB):%.5f Write(MB):%.5f",
+			float64(db.s.stor.reads())/1048576.0,
+			float64(db.s.stor.writes())/1048576.0)
+	case p == "writedelay":
+		writeDelayN, writeDelay := atomic.LoadInt32(&db.cWriteDelayN), time.Duration(atomic.LoadInt64(&db.cWriteDelay))
+		paused := atomic.LoadInt32(&db.inWritePaused) == 1
+		value = fmt.Sprintf("DelayN:%d Delay:%s Paused:%t", writeDelayN, writeDelay, paused)
+	case p == "sstables":
+		for level, tables := range v.levels {
+			value += fmt.Sprintf("--- level %d ---\n", level)
+			for _, t := range tables {
+				value += fmt.Sprintf("%d:%d[%q .. %q]\n", t.fd.Num, t.size, t.imin, t.imax)
+			}
+		}
+	case p == "blockpool":
+		value = fmt.Sprintf("%v", db.s.tops.bpool)
+	case p == "cachedblock":
+		if db.s.tops.bcache != nil {
+			value = fmt.Sprintf("%d", db.s.tops.bcache.Size())
+		} else {
+			value = "<nil>"
+		}
+	case p == "openedtables":
+		value = fmt.Sprintf("%d", db.s.tops.cache.Size())
+	case p == "alivesnaps":
+		value = fmt.Sprintf("%d", atomic.LoadInt32(&db.aliveSnaps))
+	case p == "aliveiters":
+		value = fmt.Sprintf("%d", atomic.LoadInt32(&db.aliveIters))
+	default:
+		err = ErrNotFound
+	}
+
+	return
+}
+
+// DBStats is database statistics.
+type DBStats struct {
+	WriteDelayCount    int32
+	WriteDelayDuration time.Duration
+	WritePaused        bool
+
+	AliveSnapshots int32
+	AliveIterators int32
+
+	IOWrite uint64
+	IORead  uint64
+
+	BlockCacheSize    int
+	OpenedTablesCount int
+
+	LevelSizes        []int64
+	LevelTablesCounts []int
+	LevelRead         []int64
+	LevelWrite        []int64
+	LevelDurations    []time.Duration
+}
+
+// Stats populates s with database statistics.
+func (db *DB) Stats(s *DBStats) error {
+	err := db.ok()
+	if err != nil {
+		return err
+	}
+
+	s.IORead = db.s.stor.reads()
+	s.IOWrite = db.s.stor.writes()
+	s.WriteDelayCount = atomic.LoadInt32(&db.cWriteDelayN)
+	s.WriteDelayDuration = time.Duration(atomic.LoadInt64(&db.cWriteDelay))
+	s.WritePaused = atomic.LoadInt32(&db.inWritePaused) == 1
+
+	s.OpenedTablesCount = db.s.tops.cache.Size()
+	if db.s.tops.bcache != nil {
+		s.BlockCacheSize = db.s.tops.bcache.Size()
+	} else {
+		s.BlockCacheSize = 0
+	}
+
+	s.AliveIterators = atomic.LoadInt32(&db.aliveIters)
+	s.AliveSnapshots = atomic.LoadInt32(&db.aliveSnaps)
+
+	s.LevelDurations = s.LevelDurations[:0]
+	s.LevelRead = s.LevelRead[:0]
+	s.LevelWrite = s.LevelWrite[:0]
+	s.LevelSizes = s.LevelSizes[:0]
+	s.LevelTablesCounts = s.LevelTablesCounts[:0]
+
+	v := db.s.version()
+	defer v.release()
+
+	for level, tables := range v.levels {
+		duration, read, write := db.compStats.getStat(level)
+		if len(tables) == 0 && duration == 0 {
+			continue
+		}
+		s.LevelDurations = append(s.LevelDurations, duration)
+		s.LevelRead = append(s.LevelRead, read)
+		s.LevelWrite = append(s.LevelWrite, write)
+		s.LevelSizes = append(s.LevelSizes, tables.size())
+		s.LevelTablesCounts = append(s.LevelTablesCounts, len(tables))
+	}
+
+	return nil
+}
+
+// SizeOf calculates approximate sizes of the given key ranges.
+// The length of the returned sizes are equal with the length of the given
+// ranges. The returned sizes measure storage space usage, so if the user
+// data compresses by a factor of ten, the returned sizes will be one-tenth
+// the size of the corresponding user data size.
+// The results may not include the sizes of recently written data.
+func (db *DB) SizeOf(ranges []util.Range) (Sizes, error) {
+	if err := db.ok(); err != nil {
+		return nil, err
+	}
+
+	v := db.s.version()
+	defer v.release()
+
+	sizes := make(Sizes, 0, len(ranges))
+	for _, r := range ranges {
+		imin := makeInternalKey(nil, r.Start, keyMaxSeq, keyTypeSeek)
+		imax := makeInternalKey(nil, r.Limit, keyMaxSeq, keyTypeSeek)
+		start, err := v.offsetOf(imin)
+		if err != nil {
+			return nil, err
+		}
+		limit, err := v.offsetOf(imax)
+		if err != nil {
+			return nil, err
+		}
+		var size int64
+		if limit >= start {
+			size = limit - start
+		}
+		sizes = append(sizes, size)
+	}
+
+	return sizes, nil
+}
+
+// Close closes the DB. This will also releases any outstanding snapshot,
+// abort any in-flight compaction and discard open transaction.
+//
+// It is not safe to close a DB until all outstanding iterators are released.
+// It is valid to call Close multiple times. Other methods should not be
+// called after the DB has been closed.
+func (db *DB) Close() error {
+	if !db.setClosed() {
+		return ErrClosed
+	}
+
+	start := time.Now()
+	db.log("db@close closing")
+
+	// Clear the finalizer.
+	runtime.SetFinalizer(db, nil)
+
+	// Get compaction error.
+	var err error
+	select {
+	case err = <-db.compErrC:
+		if err == ErrReadOnly {
+			err = nil
+		}
+	default:
+	}
+
+	// Signal all goroutines.
+	close(db.closeC)
+
+	// Discard open transaction.
+	if db.tr != nil {
+		db.tr.Discard()
+	}
+
+	// Acquire writer lock.
+	db.writeLockC <- struct{}{}
+
+	// Wait for all gorotines to exit.
+	db.closeW.Wait()
+
+	// Closes journal.
+	if db.journal != nil {
+		db.journal.Close()
+		db.journalWriter.Close()
+		db.journal = nil
+		db.journalWriter = nil
+	}
+
+	if db.writeDelayN > 0 {
+		db.logf("db@write was delayed N·%d T·%v", db.writeDelayN, db.writeDelay)
+	}
+
+	// Close session.
+	db.s.close()
+	db.logf("db@close done T·%v", time.Since(start))
+	db.s.release()
+
+	if db.closer != nil {
+		if err1 := db.closer.Close(); err == nil {
+			err = err1
+		}
+		db.closer = nil
+	}
+
+	// Clear memdbs.
+	db.clearMems()
+
+	return err
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_compaction.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_compaction.go
new file mode 100644
index 0000000000..0c1b9a53b8
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_compaction.go
@@ -0,0 +1,854 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"sync"
+	"time"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+var (
+	errCompactionTransactExiting = errors.New("leveldb: compaction transact exiting")
+)
+
+type cStat struct {
+	duration time.Duration
+	read     int64
+	write    int64
+}
+
+func (p *cStat) add(n *cStatStaging) {
+	p.duration += n.duration
+	p.read += n.read
+	p.write += n.write
+}
+
+func (p *cStat) get() (duration time.Duration, read, write int64) {
+	return p.duration, p.read, p.write
+}
+
+type cStatStaging struct {
+	start    time.Time
+	duration time.Duration
+	on       bool
+	read     int64
+	write    int64
+}
+
+func (p *cStatStaging) startTimer() {
+	if !p.on {
+		p.start = time.Now()
+		p.on = true
+	}
+}
+
+func (p *cStatStaging) stopTimer() {
+	if p.on {
+		p.duration += time.Since(p.start)
+		p.on = false
+	}
+}
+
+type cStats struct {
+	lk    sync.Mutex
+	stats []cStat
+}
+
+func (p *cStats) addStat(level int, n *cStatStaging) {
+	p.lk.Lock()
+	if level >= len(p.stats) {
+		newStats := make([]cStat, level+1)
+		copy(newStats, p.stats)
+		p.stats = newStats
+	}
+	p.stats[level].add(n)
+	p.lk.Unlock()
+}
+
+func (p *cStats) getStat(level int) (duration time.Duration, read, write int64) {
+	p.lk.Lock()
+	defer p.lk.Unlock()
+	if level < len(p.stats) {
+		return p.stats[level].get()
+	}
+	return
+}
+
+func (db *DB) compactionError() {
+	var err error
+noerr:
+	// No error.
+	for {
+		select {
+		case err = <-db.compErrSetC:
+			switch {
+			case err == nil:
+			case err == ErrReadOnly, errors.IsCorrupted(err):
+				goto hasperr
+			default:
+				goto haserr
+			}
+		case <-db.closeC:
+			return
+		}
+	}
+haserr:
+	// Transient error.
+	for {
+		select {
+		case db.compErrC <- err:
+		case err = <-db.compErrSetC:
+			switch {
+			case err == nil:
+				goto noerr
+			case err == ErrReadOnly, errors.IsCorrupted(err):
+				goto hasperr
+			default:
+			}
+		case <-db.closeC:
+			return
+		}
+	}
+hasperr:
+	// Persistent error.
+	for {
+		select {
+		case db.compErrC <- err:
+		case db.compPerErrC <- err:
+		case db.writeLockC <- struct{}{}:
+			// Hold write lock, so that write won't pass-through.
+			db.compWriteLocking = true
+		case <-db.closeC:
+			if db.compWriteLocking {
+				// We should release the lock or Close will hang.
+				<-db.writeLockC
+			}
+			return
+		}
+	}
+}
+
+type compactionTransactCounter int
+
+func (cnt *compactionTransactCounter) incr() {
+	*cnt++
+}
+
+type compactionTransactInterface interface {
+	run(cnt *compactionTransactCounter) error
+	revert() error
+}
+
+func (db *DB) compactionTransact(name string, t compactionTransactInterface) {
+	defer func() {
+		if x := recover(); x != nil {
+			if x == errCompactionTransactExiting {
+				if err := t.revert(); err != nil {
+					db.logf("%s revert error %q", name, err)
+				}
+			}
+			panic(x)
+		}
+	}()
+
+	const (
+		backoffMin = 1 * time.Second
+		backoffMax = 8 * time.Second
+		backoffMul = 2 * time.Second
+	)
+	var (
+		backoff  = backoffMin
+		backoffT = time.NewTimer(backoff)
+		lastCnt  = compactionTransactCounter(0)
+
+		disableBackoff = db.s.o.GetDisableCompactionBackoff()
+	)
+	for n := 0; ; n++ {
+		// Check whether the DB is closed.
+		if db.isClosed() {
+			db.logf("%s exiting", name)
+			db.compactionExitTransact()
+		} else if n > 0 {
+			db.logf("%s retrying N·%d", name, n)
+		}
+
+		// Execute.
+		cnt := compactionTransactCounter(0)
+		err := t.run(&cnt)
+		if err != nil {
+			db.logf("%s error I·%d %q", name, cnt, err)
+		}
+
+		// Set compaction error status.
+		select {
+		case db.compErrSetC <- err:
+		case perr := <-db.compPerErrC:
+			if err != nil {
+				db.logf("%s exiting (persistent error %q)", name, perr)
+				db.compactionExitTransact()
+			}
+		case <-db.closeC:
+			db.logf("%s exiting", name)
+			db.compactionExitTransact()
+		}
+		if err == nil {
+			return
+		}
+		if errors.IsCorrupted(err) {
+			db.logf("%s exiting (corruption detected)", name)
+			db.compactionExitTransact()
+		}
+
+		if !disableBackoff {
+			// Reset backoff duration if counter is advancing.
+			if cnt > lastCnt {
+				backoff = backoffMin
+				lastCnt = cnt
+			}
+
+			// Backoff.
+			backoffT.Reset(backoff)
+			if backoff < backoffMax {
+				backoff *= backoffMul
+				if backoff > backoffMax {
+					backoff = backoffMax
+				}
+			}
+			select {
+			case <-backoffT.C:
+			case <-db.closeC:
+				db.logf("%s exiting", name)
+				db.compactionExitTransact()
+			}
+		}
+	}
+}
+
+type compactionTransactFunc struct {
+	runFunc    func(cnt *compactionTransactCounter) error
+	revertFunc func() error
+}
+
+func (t *compactionTransactFunc) run(cnt *compactionTransactCounter) error {
+	return t.runFunc(cnt)
+}
+
+func (t *compactionTransactFunc) revert() error {
+	if t.revertFunc != nil {
+		return t.revertFunc()
+	}
+	return nil
+}
+
+func (db *DB) compactionTransactFunc(name string, run func(cnt *compactionTransactCounter) error, revert func() error) {
+	db.compactionTransact(name, &compactionTransactFunc{run, revert})
+}
+
+func (db *DB) compactionExitTransact() {
+	panic(errCompactionTransactExiting)
+}
+
+func (db *DB) compactionCommit(name string, rec *sessionRecord) {
+	db.compCommitLk.Lock()
+	defer db.compCommitLk.Unlock() // Defer is necessary.
+	db.compactionTransactFunc(name+"@commit", func(cnt *compactionTransactCounter) error {
+		return db.s.commit(rec)
+	}, nil)
+}
+
+func (db *DB) memCompaction() {
+	mdb := db.getFrozenMem()
+	if mdb == nil {
+		return
+	}
+	defer mdb.decref()
+
+	db.logf("memdb@flush N·%d S·%s", mdb.Len(), shortenb(mdb.Size()))
+
+	// Don't compact empty memdb.
+	if mdb.Len() == 0 {
+		db.logf("memdb@flush skipping")
+		// drop frozen memdb
+		db.dropFrozenMem()
+		return
+	}
+
+	// Pause table compaction.
+	resumeC := make(chan struct{})
+	select {
+	case db.tcompPauseC <- (chan<- struct{})(resumeC):
+	case <-db.compPerErrC:
+		close(resumeC)
+		resumeC = nil
+	case <-db.closeC:
+		db.compactionExitTransact()
+	}
+
+	var (
+		rec        = &sessionRecord{}
+		stats      = &cStatStaging{}
+		flushLevel int
+	)
+
+	// Generate tables.
+	db.compactionTransactFunc("memdb@flush", func(cnt *compactionTransactCounter) (err error) {
+		stats.startTimer()
+		flushLevel, err = db.s.flushMemdb(rec, mdb.DB, db.memdbMaxLevel)
+		stats.stopTimer()
+		return
+	}, func() error {
+		for _, r := range rec.addedTables {
+			db.logf("memdb@flush revert @%d", r.num)
+			if err := db.s.stor.Remove(storage.FileDesc{Type: storage.TypeTable, Num: r.num}); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+
+	rec.setJournalNum(db.journalFd.Num)
+	rec.setSeqNum(db.frozenSeq)
+
+	// Commit.
+	stats.startTimer()
+	db.compactionCommit("memdb", rec)
+	stats.stopTimer()
+
+	db.logf("memdb@flush committed F·%d T·%v", len(rec.addedTables), stats.duration)
+
+	for _, r := range rec.addedTables {
+		stats.write += r.size
+	}
+	db.compStats.addStat(flushLevel, stats)
+
+	// Drop frozen memdb.
+	db.dropFrozenMem()
+
+	// Resume table compaction.
+	if resumeC != nil {
+		select {
+		case <-resumeC:
+			close(resumeC)
+		case <-db.closeC:
+			db.compactionExitTransact()
+		}
+	}
+
+	// Trigger table compaction.
+	db.compTrigger(db.tcompCmdC)
+}
+
+type tableCompactionBuilder struct {
+	db           *DB
+	s            *session
+	c            *compaction
+	rec          *sessionRecord
+	stat0, stat1 *cStatStaging
+
+	snapHasLastUkey bool
+	snapLastUkey    []byte
+	snapLastSeq     uint64
+	snapIter        int
+	snapKerrCnt     int
+	snapDropCnt     int
+
+	kerrCnt int
+	dropCnt int
+
+	minSeq    uint64
+	strict    bool
+	tableSize int
+
+	tw *tWriter
+}
+
+func (b *tableCompactionBuilder) appendKV(key, value []byte) error {
+	// Create new table if not already.
+	if b.tw == nil {
+		// Check for pause event.
+		if b.db != nil {
+			select {
+			case ch := <-b.db.tcompPauseC:
+				b.db.pauseCompaction(ch)
+			case <-b.db.closeC:
+				b.db.compactionExitTransact()
+			default:
+			}
+		}
+
+		// Create new table.
+		var err error
+		b.tw, err = b.s.tops.create()
+		if err != nil {
+			return err
+		}
+	}
+
+	// Write key/value into table.
+	return b.tw.append(key, value)
+}
+
+func (b *tableCompactionBuilder) needFlush() bool {
+	return b.tw.tw.BytesLen() >= b.tableSize
+}
+
+func (b *tableCompactionBuilder) flush() error {
+	t, err := b.tw.finish()
+	if err != nil {
+		return err
+	}
+	b.rec.addTableFile(b.c.sourceLevel+1, t)
+	b.stat1.write += t.size
+	b.s.logf("table@build created L%d@%d N·%d S·%s %q:%q", b.c.sourceLevel+1, t.fd.Num, b.tw.tw.EntriesLen(), shortenb(int(t.size)), t.imin, t.imax)
+	b.tw = nil
+	return nil
+}
+
+func (b *tableCompactionBuilder) cleanup() {
+	if b.tw != nil {
+		b.tw.drop()
+		b.tw = nil
+	}
+}
+
+func (b *tableCompactionBuilder) run(cnt *compactionTransactCounter) error {
+	snapResumed := b.snapIter > 0
+	hasLastUkey := b.snapHasLastUkey // The key might has zero length, so this is necessary.
+	lastUkey := append([]byte{}, b.snapLastUkey...)
+	lastSeq := b.snapLastSeq
+	b.kerrCnt = b.snapKerrCnt
+	b.dropCnt = b.snapDropCnt
+	// Restore compaction state.
+	b.c.restore()
+
+	defer b.cleanup()
+
+	b.stat1.startTimer()
+	defer b.stat1.stopTimer()
+
+	iter := b.c.newIterator()
+	defer iter.Release()
+	for i := 0; iter.Next(); i++ {
+		// Incr transact counter.
+		cnt.incr()
+
+		// Skip until last state.
+		if i < b.snapIter {
+			continue
+		}
+
+		resumed := false
+		if snapResumed {
+			resumed = true
+			snapResumed = false
+		}
+
+		ikey := iter.Key()
+		ukey, seq, kt, kerr := parseInternalKey(ikey)
+
+		if kerr == nil {
+			shouldStop := !resumed && b.c.shouldStopBefore(ikey)
+
+			if !hasLastUkey || b.s.icmp.uCompare(lastUkey, ukey) != 0 {
+				// First occurrence of this user key.
+
+				// Only rotate tables if ukey doesn't hop across.
+				if b.tw != nil && (shouldStop || b.needFlush()) {
+					if err := b.flush(); err != nil {
+						return err
+					}
+
+					// Creates snapshot of the state.
+					b.c.save()
+					b.snapHasLastUkey = hasLastUkey
+					b.snapLastUkey = append(b.snapLastUkey[:0], lastUkey...)
+					b.snapLastSeq = lastSeq
+					b.snapIter = i
+					b.snapKerrCnt = b.kerrCnt
+					b.snapDropCnt = b.dropCnt
+				}
+
+				hasLastUkey = true
+				lastUkey = append(lastUkey[:0], ukey...)
+				lastSeq = keyMaxSeq
+			}
+
+			switch {
+			case lastSeq <= b.minSeq:
+				// Dropped because newer entry for same user key exist
+				fallthrough // (A)
+			case kt == keyTypeDel && seq <= b.minSeq && b.c.baseLevelForKey(lastUkey):
+				// For this user key:
+				// (1) there is no data in higher levels
+				// (2) data in lower levels will have larger seq numbers
+				// (3) data in layers that are being compacted here and have
+				//     smaller seq numbers will be dropped in the next
+				//     few iterations of this loop (by rule (A) above).
+				// Therefore this deletion marker is obsolete and can be dropped.
+				lastSeq = seq
+				b.dropCnt++
+				continue
+			default:
+				lastSeq = seq
+			}
+		} else {
+			if b.strict {
+				return kerr
+			}
+
+			// Don't drop corrupted keys.
+			hasLastUkey = false
+			lastUkey = lastUkey[:0]
+			lastSeq = keyMaxSeq
+			b.kerrCnt++
+		}
+
+		if err := b.appendKV(ikey, iter.Value()); err != nil {
+			return err
+		}
+	}
+
+	if err := iter.Error(); err != nil {
+		return err
+	}
+
+	// Finish last table.
+	if b.tw != nil && !b.tw.empty() {
+		return b.flush()
+	}
+	return nil
+}
+
+func (b *tableCompactionBuilder) revert() error {
+	for _, at := range b.rec.addedTables {
+		b.s.logf("table@build revert @%d", at.num)
+		if err := b.s.stor.Remove(storage.FileDesc{Type: storage.TypeTable, Num: at.num}); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (db *DB) tableCompaction(c *compaction, noTrivial bool) {
+	defer c.release()
+
+	rec := &sessionRecord{}
+	rec.addCompPtr(c.sourceLevel, c.imax)
+
+	if !noTrivial && c.trivial() {
+		t := c.levels[0][0]
+		db.logf("table@move L%d@%d -> L%d", c.sourceLevel, t.fd.Num, c.sourceLevel+1)
+		rec.delTable(c.sourceLevel, t.fd.Num)
+		rec.addTableFile(c.sourceLevel+1, t)
+		db.compactionCommit("table-move", rec)
+		return
+	}
+
+	var stats [2]cStatStaging
+	for i, tables := range c.levels {
+		for _, t := range tables {
+			stats[i].read += t.size
+			// Insert deleted tables into record
+			rec.delTable(c.sourceLevel+i, t.fd.Num)
+		}
+	}
+	sourceSize := int(stats[0].read + stats[1].read)
+	minSeq := db.minSeq()
+	db.logf("table@compaction L%d·%d -> L%d·%d S·%s Q·%d", c.sourceLevel, len(c.levels[0]), c.sourceLevel+1, len(c.levels[1]), shortenb(sourceSize), minSeq)
+
+	b := &tableCompactionBuilder{
+		db:        db,
+		s:         db.s,
+		c:         c,
+		rec:       rec,
+		stat1:     &stats[1],
+		minSeq:    minSeq,
+		strict:    db.s.o.GetStrict(opt.StrictCompaction),
+		tableSize: db.s.o.GetCompactionTableSize(c.sourceLevel + 1),
+	}
+	db.compactionTransact("table@build", b)
+
+	// Commit.
+	stats[1].startTimer()
+	db.compactionCommit("table", rec)
+	stats[1].stopTimer()
+
+	resultSize := int(stats[1].write)
+	db.logf("table@compaction committed F%s S%s Ke·%d D·%d T·%v", sint(len(rec.addedTables)-len(rec.deletedTables)), sshortenb(resultSize-sourceSize), b.kerrCnt, b.dropCnt, stats[1].duration)
+
+	// Save compaction stats
+	for i := range stats {
+		db.compStats.addStat(c.sourceLevel+1, &stats[i])
+	}
+}
+
+func (db *DB) tableRangeCompaction(level int, umin, umax []byte) error {
+	db.logf("table@compaction range L%d %q:%q", level, umin, umax)
+	if level >= 0 {
+		if c := db.s.getCompactionRange(level, umin, umax, true); c != nil {
+			db.tableCompaction(c, true)
+		}
+	} else {
+		// Retry until nothing to compact.
+		for {
+			compacted := false
+
+			// Scan for maximum level with overlapped tables.
+			v := db.s.version()
+			m := 1
+			for i := m; i < len(v.levels); i++ {
+				tables := v.levels[i]
+				if tables.overlaps(db.s.icmp, umin, umax, false) {
+					m = i
+				}
+			}
+			v.release()
+
+			for level := 0; level < m; level++ {
+				if c := db.s.getCompactionRange(level, umin, umax, false); c != nil {
+					db.tableCompaction(c, true)
+					compacted = true
+				}
+			}
+
+			if !compacted {
+				break
+			}
+		}
+	}
+
+	return nil
+}
+
+func (db *DB) tableAutoCompaction() {
+	if c := db.s.pickCompaction(); c != nil {
+		db.tableCompaction(c, false)
+	}
+}
+
+func (db *DB) tableNeedCompaction() bool {
+	v := db.s.version()
+	defer v.release()
+	return v.needCompaction()
+}
+
+// resumeWrite returns an indicator whether we should resume write operation if enough level0 files are compacted.
+func (db *DB) resumeWrite() bool {
+	v := db.s.version()
+	defer v.release()
+	if v.tLen(0) < db.s.o.GetWriteL0PauseTrigger() {
+		return true
+	}
+	return false
+}
+
+func (db *DB) pauseCompaction(ch chan<- struct{}) {
+	select {
+	case ch <- struct{}{}:
+	case <-db.closeC:
+		db.compactionExitTransact()
+	}
+}
+
+type cCmd interface {
+	ack(err error)
+}
+
+type cAuto struct {
+	// Note for table compaction, an non-empty ackC represents it's a compaction waiting command.
+	ackC chan<- error
+}
+
+func (r cAuto) ack(err error) {
+	if r.ackC != nil {
+		defer func() {
+			recover()
+		}()
+		r.ackC <- err
+	}
+}
+
+type cRange struct {
+	level    int
+	min, max []byte
+	ackC     chan<- error
+}
+
+func (r cRange) ack(err error) {
+	if r.ackC != nil {
+		defer func() {
+			recover()
+		}()
+		r.ackC <- err
+	}
+}
+
+// This will trigger auto compaction but will not wait for it.
+func (db *DB) compTrigger(compC chan<- cCmd) {
+	select {
+	case compC <- cAuto{}:
+	default:
+	}
+}
+
+// This will trigger auto compaction and/or wait for all compaction to be done.
+func (db *DB) compTriggerWait(compC chan<- cCmd) (err error) {
+	ch := make(chan error)
+	defer close(ch)
+	// Send cmd.
+	select {
+	case compC <- cAuto{ch}:
+	case err = <-db.compErrC:
+		return
+	case <-db.closeC:
+		return ErrClosed
+	}
+	// Wait cmd.
+	select {
+	case err = <-ch:
+	case err = <-db.compErrC:
+	case <-db.closeC:
+		return ErrClosed
+	}
+	return err
+}
+
+// Send range compaction request.
+func (db *DB) compTriggerRange(compC chan<- cCmd, level int, min, max []byte) (err error) {
+	ch := make(chan error)
+	defer close(ch)
+	// Send cmd.
+	select {
+	case compC <- cRange{level, min, max, ch}:
+	case err := <-db.compErrC:
+		return err
+	case <-db.closeC:
+		return ErrClosed
+	}
+	// Wait cmd.
+	select {
+	case err = <-ch:
+	case err = <-db.compErrC:
+	case <-db.closeC:
+		return ErrClosed
+	}
+	return err
+}
+
+func (db *DB) mCompaction() {
+	var x cCmd
+
+	defer func() {
+		if x := recover(); x != nil {
+			if x != errCompactionTransactExiting {
+				panic(x)
+			}
+		}
+		if x != nil {
+			x.ack(ErrClosed)
+		}
+		db.closeW.Done()
+	}()
+
+	for {
+		select {
+		case x = <-db.mcompCmdC:
+			switch x.(type) {
+			case cAuto:
+				db.memCompaction()
+				x.ack(nil)
+				x = nil
+			default:
+				panic("leveldb: unknown command")
+			}
+		case <-db.closeC:
+			return
+		}
+	}
+}
+
+func (db *DB) tCompaction() {
+	var (
+		x     cCmd
+		waitQ []cCmd
+	)
+
+	defer func() {
+		if x := recover(); x != nil {
+			if x != errCompactionTransactExiting {
+				panic(x)
+			}
+		}
+		for i := range waitQ {
+			waitQ[i].ack(ErrClosed)
+			waitQ[i] = nil
+		}
+		if x != nil {
+			x.ack(ErrClosed)
+		}
+		db.closeW.Done()
+	}()
+
+	for {
+		if db.tableNeedCompaction() {
+			select {
+			case x = <-db.tcompCmdC:
+			case ch := <-db.tcompPauseC:
+				db.pauseCompaction(ch)
+				continue
+			case <-db.closeC:
+				return
+			default:
+			}
+			// Resume write operation as soon as possible.
+			if len(waitQ) > 0 && db.resumeWrite() {
+				for i := range waitQ {
+					waitQ[i].ack(nil)
+					waitQ[i] = nil
+				}
+				waitQ = waitQ[:0]
+			}
+		} else {
+			for i := range waitQ {
+				waitQ[i].ack(nil)
+				waitQ[i] = nil
+			}
+			waitQ = waitQ[:0]
+			select {
+			case x = <-db.tcompCmdC:
+			case ch := <-db.tcompPauseC:
+				db.pauseCompaction(ch)
+				continue
+			case <-db.closeC:
+				return
+			}
+		}
+		if x != nil {
+			switch cmd := x.(type) {
+			case cAuto:
+				if cmd.ackC != nil {
+					// Check the write pause state before caching it.
+					if db.resumeWrite() {
+						x.ack(nil)
+					} else {
+						waitQ = append(waitQ, x)
+					}
+				}
+			case cRange:
+				x.ack(db.tableRangeCompaction(cmd.level, cmd.min, cmd.max))
+			default:
+				panic("leveldb: unknown command")
+			}
+			x = nil
+		}
+		db.tableAutoCompaction()
+	}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_iter.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_iter.go
new file mode 100644
index 0000000000..03c24cdab5
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_iter.go
@@ -0,0 +1,360 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"errors"
+	"math/rand"
+	"runtime"
+	"sync"
+	"sync/atomic"
+
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+var (
+	errInvalidInternalKey = errors.New("leveldb: Iterator: invalid internal key")
+)
+
+type memdbReleaser struct {
+	once sync.Once
+	m    *memDB
+}
+
+func (mr *memdbReleaser) Release() {
+	mr.once.Do(func() {
+		mr.m.decref()
+	})
+}
+
+func (db *DB) newRawIterator(auxm *memDB, auxt tFiles, slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+	strict := opt.GetStrict(db.s.o.Options, ro, opt.StrictReader)
+	em, fm := db.getMems()
+	v := db.s.version()
+
+	tableIts := v.getIterators(slice, ro)
+	n := len(tableIts) + len(auxt) + 3
+	its := make([]iterator.Iterator, 0, n)
+
+	if auxm != nil {
+		ami := auxm.NewIterator(slice)
+		ami.SetReleaser(&memdbReleaser{m: auxm})
+		its = append(its, ami)
+	}
+	for _, t := range auxt {
+		its = append(its, v.s.tops.newIterator(t, slice, ro))
+	}
+
+	emi := em.NewIterator(slice)
+	emi.SetReleaser(&memdbReleaser{m: em})
+	its = append(its, emi)
+	if fm != nil {
+		fmi := fm.NewIterator(slice)
+		fmi.SetReleaser(&memdbReleaser{m: fm})
+		its = append(its, fmi)
+	}
+	its = append(its, tableIts...)
+	mi := iterator.NewMergedIterator(its, db.s.icmp, strict)
+	mi.SetReleaser(&versionReleaser{v: v})
+	return mi
+}
+
+func (db *DB) newIterator(auxm *memDB, auxt tFiles, seq uint64, slice *util.Range, ro *opt.ReadOptions) *dbIter {
+	var islice *util.Range
+	if slice != nil {
+		islice = &util.Range{}
+		if slice.Start != nil {
+			islice.Start = makeInternalKey(nil, slice.Start, keyMaxSeq, keyTypeSeek)
+		}
+		if slice.Limit != nil {
+			islice.Limit = makeInternalKey(nil, slice.Limit, keyMaxSeq, keyTypeSeek)
+		}
+	}
+	rawIter := db.newRawIterator(auxm, auxt, islice, ro)
+	iter := &dbIter{
+		db:     db,
+		icmp:   db.s.icmp,
+		iter:   rawIter,
+		seq:    seq,
+		strict: opt.GetStrict(db.s.o.Options, ro, opt.StrictReader),
+		key:    make([]byte, 0),
+		value:  make([]byte, 0),
+	}
+	atomic.AddInt32(&db.aliveIters, 1)
+	runtime.SetFinalizer(iter, (*dbIter).Release)
+	return iter
+}
+
+func (db *DB) iterSamplingRate() int {
+	return rand.Intn(2 * db.s.o.GetIteratorSamplingRate())
+}
+
+type dir int
+
+const (
+	dirReleased dir = iota - 1
+	dirSOI
+	dirEOI
+	dirBackward
+	dirForward
+)
+
+// dbIter represent an interator states over a database session.
+type dbIter struct {
+	db     *DB
+	icmp   *iComparer
+	iter   iterator.Iterator
+	seq    uint64
+	strict bool
+
+	smaplingGap int
+	dir         dir
+	key         []byte
+	value       []byte
+	err         error
+	releaser    util.Releaser
+}
+
+func (i *dbIter) sampleSeek() {
+	ikey := i.iter.Key()
+	i.smaplingGap -= len(ikey) + len(i.iter.Value())
+	for i.smaplingGap < 0 {
+		i.smaplingGap += i.db.iterSamplingRate()
+		i.db.sampleSeek(ikey)
+	}
+}
+
+func (i *dbIter) setErr(err error) {
+	i.err = err
+	i.key = nil
+	i.value = nil
+}
+
+func (i *dbIter) iterErr() {
+	if err := i.iter.Error(); err != nil {
+		i.setErr(err)
+	}
+}
+
+func (i *dbIter) Valid() bool {
+	return i.err == nil && i.dir > dirEOI
+}
+
+func (i *dbIter) First() bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.iter.First() {
+		i.dir = dirSOI
+		return i.next()
+	}
+	i.dir = dirEOI
+	i.iterErr()
+	return false
+}
+
+func (i *dbIter) Last() bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.iter.Last() {
+		return i.prev()
+	}
+	i.dir = dirSOI
+	i.iterErr()
+	return false
+}
+
+func (i *dbIter) Seek(key []byte) bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	ikey := makeInternalKey(nil, key, i.seq, keyTypeSeek)
+	if i.iter.Seek(ikey) {
+		i.dir = dirSOI
+		return i.next()
+	}
+	i.dir = dirEOI
+	i.iterErr()
+	return false
+}
+
+func (i *dbIter) next() bool {
+	for {
+		if ukey, seq, kt, kerr := parseInternalKey(i.iter.Key()); kerr == nil {
+			i.sampleSeek()
+			if seq <= i.seq {
+				switch kt {
+				case keyTypeDel:
+					// Skip deleted key.
+					i.key = append(i.key[:0], ukey...)
+					i.dir = dirForward
+				case keyTypeVal:
+					if i.dir == dirSOI || i.icmp.uCompare(ukey, i.key) > 0 {
+						i.key = append(i.key[:0], ukey...)
+						i.value = append(i.value[:0], i.iter.Value()...)
+						i.dir = dirForward
+						return true
+					}
+				}
+			}
+		} else if i.strict {
+			i.setErr(kerr)
+			break
+		}
+		if !i.iter.Next() {
+			i.dir = dirEOI
+			i.iterErr()
+			break
+		}
+	}
+	return false
+}
+
+func (i *dbIter) Next() bool {
+	if i.dir == dirEOI || i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if !i.iter.Next() || (i.dir == dirBackward && !i.iter.Next()) {
+		i.dir = dirEOI
+		i.iterErr()
+		return false
+	}
+	return i.next()
+}
+
+func (i *dbIter) prev() bool {
+	i.dir = dirBackward
+	del := true
+	if i.iter.Valid() {
+		for {
+			if ukey, seq, kt, kerr := parseInternalKey(i.iter.Key()); kerr == nil {
+				i.sampleSeek()
+				if seq <= i.seq {
+					if !del && i.icmp.uCompare(ukey, i.key) < 0 {
+						return true
+					}
+					del = (kt == keyTypeDel)
+					if !del {
+						i.key = append(i.key[:0], ukey...)
+						i.value = append(i.value[:0], i.iter.Value()...)
+					}
+				}
+			} else if i.strict {
+				i.setErr(kerr)
+				return false
+			}
+			if !i.iter.Prev() {
+				break
+			}
+		}
+	}
+	if del {
+		i.dir = dirSOI
+		i.iterErr()
+		return false
+	}
+	return true
+}
+
+func (i *dbIter) Prev() bool {
+	if i.dir == dirSOI || i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	switch i.dir {
+	case dirEOI:
+		return i.Last()
+	case dirForward:
+		for i.iter.Prev() {
+			if ukey, _, _, kerr := parseInternalKey(i.iter.Key()); kerr == nil {
+				i.sampleSeek()
+				if i.icmp.uCompare(ukey, i.key) < 0 {
+					goto cont
+				}
+			} else if i.strict {
+				i.setErr(kerr)
+				return false
+			}
+		}
+		i.dir = dirSOI
+		i.iterErr()
+		return false
+	}
+
+cont:
+	return i.prev()
+}
+
+func (i *dbIter) Key() []byte {
+	if i.err != nil || i.dir <= dirEOI {
+		return nil
+	}
+	return i.key
+}
+
+func (i *dbIter) Value() []byte {
+	if i.err != nil || i.dir <= dirEOI {
+		return nil
+	}
+	return i.value
+}
+
+func (i *dbIter) Release() {
+	if i.dir != dirReleased {
+		// Clear the finalizer.
+		runtime.SetFinalizer(i, nil)
+
+		if i.releaser != nil {
+			i.releaser.Release()
+			i.releaser = nil
+		}
+
+		i.dir = dirReleased
+		i.key = nil
+		i.value = nil
+		i.iter.Release()
+		i.iter = nil
+		atomic.AddInt32(&i.db.aliveIters, -1)
+		i.db = nil
+	}
+}
+
+func (i *dbIter) SetReleaser(releaser util.Releaser) {
+	if i.dir == dirReleased {
+		panic(util.ErrReleased)
+	}
+	if i.releaser != nil && releaser != nil {
+		panic(util.ErrHasReleaser)
+	}
+	i.releaser = releaser
+}
+
+func (i *dbIter) Error() error {
+	return i.err
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_snapshot.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_snapshot.go
new file mode 100644
index 0000000000..2c69d2e531
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_snapshot.go
@@ -0,0 +1,183 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"container/list"
+	"fmt"
+	"runtime"
+	"sync"
+	"sync/atomic"
+
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+type snapshotElement struct {
+	seq uint64
+	ref int
+	e   *list.Element
+}
+
+// Acquires a snapshot, based on latest sequence.
+func (db *DB) acquireSnapshot() *snapshotElement {
+	db.snapsMu.Lock()
+	defer db.snapsMu.Unlock()
+
+	seq := db.getSeq()
+
+	if e := db.snapsList.Back(); e != nil {
+		se := e.Value.(*snapshotElement)
+		if se.seq == seq {
+			se.ref++
+			return se
+		} else if seq < se.seq {
+			panic("leveldb: sequence number is not increasing")
+		}
+	}
+	se := &snapshotElement{seq: seq, ref: 1}
+	se.e = db.snapsList.PushBack(se)
+	return se
+}
+
+// Releases given snapshot element.
+func (db *DB) releaseSnapshot(se *snapshotElement) {
+	db.snapsMu.Lock()
+	defer db.snapsMu.Unlock()
+
+	se.ref--
+	if se.ref == 0 {
+		db.snapsList.Remove(se.e)
+		se.e = nil
+	} else if se.ref < 0 {
+		panic("leveldb: Snapshot: negative element reference")
+	}
+}
+
+// Gets minimum sequence that not being snapshotted.
+func (db *DB) minSeq() uint64 {
+	db.snapsMu.Lock()
+	defer db.snapsMu.Unlock()
+
+	if e := db.snapsList.Front(); e != nil {
+		return e.Value.(*snapshotElement).seq
+	}
+
+	return db.getSeq()
+}
+
+// Snapshot is a DB snapshot.
+type Snapshot struct {
+	db       *DB
+	elem     *snapshotElement
+	mu       sync.RWMutex
+	released bool
+}
+
+// Creates new snapshot object.
+func (db *DB) newSnapshot() *Snapshot {
+	snap := &Snapshot{
+		db:   db,
+		elem: db.acquireSnapshot(),
+	}
+	atomic.AddInt32(&db.aliveSnaps, 1)
+	runtime.SetFinalizer(snap, (*Snapshot).Release)
+	return snap
+}
+
+func (snap *Snapshot) String() string {
+	return fmt.Sprintf("leveldb.Snapshot{%d}", snap.elem.seq)
+}
+
+// Get gets the value for the given key. It returns ErrNotFound if
+// the DB does not contains the key.
+//
+// The caller should not modify the contents of the returned slice, but
+// it is safe to modify the contents of the argument after Get returns.
+func (snap *Snapshot) Get(key []byte, ro *opt.ReadOptions) (value []byte, err error) {
+	err = snap.db.ok()
+	if err != nil {
+		return
+	}
+	snap.mu.RLock()
+	defer snap.mu.RUnlock()
+	if snap.released {
+		err = ErrSnapshotReleased
+		return
+	}
+	return snap.db.get(nil, nil, key, snap.elem.seq, ro)
+}
+
+// Has returns true if the DB does contains the given key.
+//
+// It is safe to modify the contents of the argument after Get returns.
+func (snap *Snapshot) Has(key []byte, ro *opt.ReadOptions) (ret bool, err error) {
+	err = snap.db.ok()
+	if err != nil {
+		return
+	}
+	snap.mu.RLock()
+	defer snap.mu.RUnlock()
+	if snap.released {
+		err = ErrSnapshotReleased
+		return
+	}
+	return snap.db.has(nil, nil, key, snap.elem.seq, ro)
+}
+
+// NewIterator returns an iterator for the snapshot of the underlying DB.
+// The returned iterator is not safe for concurrent use, but it is safe to use
+// multiple iterators concurrently, with each in a dedicated goroutine.
+// It is also safe to use an iterator concurrently with modifying its
+// underlying DB. The resultant key/value pairs are guaranteed to be
+// consistent.
+//
+// Slice allows slicing the iterator to only contains keys in the given
+// range. A nil Range.Start is treated as a key before all keys in the
+// DB. And a nil Range.Limit is treated as a key after all keys in
+// the DB.
+//
+// The iterator must be released after use, by calling Release method.
+// Releasing the snapshot doesn't mean releasing the iterator too, the
+// iterator would be still valid until released.
+//
+// Also read Iterator documentation of the leveldb/iterator package.
+func (snap *Snapshot) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+	if err := snap.db.ok(); err != nil {
+		return iterator.NewEmptyIterator(err)
+	}
+	snap.mu.Lock()
+	defer snap.mu.Unlock()
+	if snap.released {
+		return iterator.NewEmptyIterator(ErrSnapshotReleased)
+	}
+	// Since iterator already hold version ref, it doesn't need to
+	// hold snapshot ref.
+	return snap.db.newIterator(nil, nil, snap.elem.seq, slice, ro)
+}
+
+// Release releases the snapshot. This will not release any returned
+// iterators, the iterators would still be valid until released or the
+// underlying DB is closed.
+//
+// Other methods should not be called after the snapshot has been released.
+func (snap *Snapshot) Release() {
+	snap.mu.Lock()
+	defer snap.mu.Unlock()
+
+	if !snap.released {
+		// Clear the finalizer.
+		runtime.SetFinalizer(snap, nil)
+
+		snap.released = true
+		snap.db.releaseSnapshot(snap.elem)
+		atomic.AddInt32(&snap.db.aliveSnaps, -1)
+		snap.db = nil
+		snap.elem = nil
+	}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_state.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_state.go
new file mode 100644
index 0000000000..65e1c54bb4
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_state.go
@@ -0,0 +1,239 @@
+// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"errors"
+	"sync/atomic"
+	"time"
+
+	"github.com/syndtr/goleveldb/leveldb/journal"
+	"github.com/syndtr/goleveldb/leveldb/memdb"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+var (
+	errHasFrozenMem = errors.New("has frozen mem")
+)
+
+type memDB struct {
+	db *DB
+	*memdb.DB
+	ref int32
+}
+
+func (m *memDB) getref() int32 {
+	return atomic.LoadInt32(&m.ref)
+}
+
+func (m *memDB) incref() {
+	atomic.AddInt32(&m.ref, 1)
+}
+
+func (m *memDB) decref() {
+	if ref := atomic.AddInt32(&m.ref, -1); ref == 0 {
+		// Only put back memdb with std capacity.
+		if m.Capacity() == m.db.s.o.GetWriteBuffer() {
+			m.Reset()
+			m.db.mpoolPut(m.DB)
+		}
+		m.db = nil
+		m.DB = nil
+	} else if ref < 0 {
+		panic("negative memdb ref")
+	}
+}
+
+// Get latest sequence number.
+func (db *DB) getSeq() uint64 {
+	return atomic.LoadUint64(&db.seq)
+}
+
+// Atomically adds delta to seq.
+func (db *DB) addSeq(delta uint64) {
+	atomic.AddUint64(&db.seq, delta)
+}
+
+func (db *DB) setSeq(seq uint64) {
+	atomic.StoreUint64(&db.seq, seq)
+}
+
+func (db *DB) sampleSeek(ikey internalKey) {
+	v := db.s.version()
+	if v.sampleSeek(ikey) {
+		// Trigger table compaction.
+		db.compTrigger(db.tcompCmdC)
+	}
+	v.release()
+}
+
+func (db *DB) mpoolPut(mem *memdb.DB) {
+	if !db.isClosed() {
+		select {
+		case db.memPool <- mem:
+		default:
+		}
+	}
+}
+
+func (db *DB) mpoolGet(n int) *memDB {
+	var mdb *memdb.DB
+	select {
+	case mdb = <-db.memPool:
+	default:
+	}
+	if mdb == nil || mdb.Capacity() < n {
+		mdb = memdb.New(db.s.icmp, maxInt(db.s.o.GetWriteBuffer(), n))
+	}
+	return &memDB{
+		db: db,
+		DB: mdb,
+	}
+}
+
+func (db *DB) mpoolDrain() {
+	ticker := time.NewTicker(30 * time.Second)
+	for {
+		select {
+		case <-ticker.C:
+			select {
+			case <-db.memPool:
+			default:
+			}
+		case <-db.closeC:
+			ticker.Stop()
+			// Make sure the pool is drained.
+			select {
+			case <-db.memPool:
+			case <-time.After(time.Second):
+			}
+			close(db.memPool)
+			return
+		}
+	}
+}
+
+// Create new memdb and froze the old one; need external synchronization.
+// newMem only called synchronously by the writer.
+func (db *DB) newMem(n int) (mem *memDB, err error) {
+	fd := storage.FileDesc{Type: storage.TypeJournal, Num: db.s.allocFileNum()}
+	w, err := db.s.stor.Create(fd)
+	if err != nil {
+		db.s.reuseFileNum(fd.Num)
+		return
+	}
+
+	db.memMu.Lock()
+	defer db.memMu.Unlock()
+
+	if db.frozenMem != nil {
+		return nil, errHasFrozenMem
+	}
+
+	if db.journal == nil {
+		db.journal = journal.NewWriter(w)
+	} else {
+		db.journal.Reset(w)
+		db.journalWriter.Close()
+		db.frozenJournalFd = db.journalFd
+	}
+	db.journalWriter = w
+	db.journalFd = fd
+	db.frozenMem = db.mem
+	mem = db.mpoolGet(n)
+	mem.incref() // for self
+	mem.incref() // for caller
+	db.mem = mem
+	// The seq only incremented by the writer. And whoever called newMem
+	// should hold write lock, so no need additional synchronization here.
+	db.frozenSeq = db.seq
+	return
+}
+
+// Get all memdbs.
+func (db *DB) getMems() (e, f *memDB) {
+	db.memMu.RLock()
+	defer db.memMu.RUnlock()
+	if db.mem != nil {
+		db.mem.incref()
+	} else if !db.isClosed() {
+		panic("nil effective mem")
+	}
+	if db.frozenMem != nil {
+		db.frozenMem.incref()
+	}
+	return db.mem, db.frozenMem
+}
+
+// Get effective memdb.
+func (db *DB) getEffectiveMem() *memDB {
+	db.memMu.RLock()
+	defer db.memMu.RUnlock()
+	if db.mem != nil {
+		db.mem.incref()
+	} else if !db.isClosed() {
+		panic("nil effective mem")
+	}
+	return db.mem
+}
+
+// Check whether we has frozen memdb.
+func (db *DB) hasFrozenMem() bool {
+	db.memMu.RLock()
+	defer db.memMu.RUnlock()
+	return db.frozenMem != nil
+}
+
+// Get frozen memdb.
+func (db *DB) getFrozenMem() *memDB {
+	db.memMu.RLock()
+	defer db.memMu.RUnlock()
+	if db.frozenMem != nil {
+		db.frozenMem.incref()
+	}
+	return db.frozenMem
+}
+
+// Drop frozen memdb; assume that frozen memdb isn't nil.
+func (db *DB) dropFrozenMem() {
+	db.memMu.Lock()
+	if err := db.s.stor.Remove(db.frozenJournalFd); err != nil {
+		db.logf("journal@remove removing @%d %q", db.frozenJournalFd.Num, err)
+	} else {
+		db.logf("journal@remove removed @%d", db.frozenJournalFd.Num)
+	}
+	db.frozenJournalFd = storage.FileDesc{}
+	db.frozenMem.decref()
+	db.frozenMem = nil
+	db.memMu.Unlock()
+}
+
+// Clear mems ptr; used by DB.Close().
+func (db *DB) clearMems() {
+	db.memMu.Lock()
+	db.mem = nil
+	db.frozenMem = nil
+	db.memMu.Unlock()
+}
+
+// Set closed flag; return true if not already closed.
+func (db *DB) setClosed() bool {
+	return atomic.CompareAndSwapUint32(&db.closed, 0, 1)
+}
+
+// Check whether DB was closed.
+func (db *DB) isClosed() bool {
+	return atomic.LoadUint32(&db.closed) != 0
+}
+
+// Check read ok status.
+func (db *DB) ok() error {
+	if db.isClosed() {
+		return ErrClosed
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go
new file mode 100644
index 0000000000..b8f7e7d21d
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_transaction.go
@@ -0,0 +1,325 @@
+// Copyright (c) 2016, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+var errTransactionDone = errors.New("leveldb: transaction already closed")
+
+// Transaction is the transaction handle.
+type Transaction struct {
+	db        *DB
+	lk        sync.RWMutex
+	seq       uint64
+	mem       *memDB
+	tables    tFiles
+	ikScratch []byte
+	rec       sessionRecord
+	stats     cStatStaging
+	closed    bool
+}
+
+// Get gets the value for the given key. It returns ErrNotFound if the
+// DB does not contains the key.
+//
+// The returned slice is its own copy, it is safe to modify the contents
+// of the returned slice.
+// It is safe to modify the contents of the argument after Get returns.
+func (tr *Transaction) Get(key []byte, ro *opt.ReadOptions) ([]byte, error) {
+	tr.lk.RLock()
+	defer tr.lk.RUnlock()
+	if tr.closed {
+		return nil, errTransactionDone
+	}
+	return tr.db.get(tr.mem.DB, tr.tables, key, tr.seq, ro)
+}
+
+// Has returns true if the DB does contains the given key.
+//
+// It is safe to modify the contents of the argument after Has returns.
+func (tr *Transaction) Has(key []byte, ro *opt.ReadOptions) (bool, error) {
+	tr.lk.RLock()
+	defer tr.lk.RUnlock()
+	if tr.closed {
+		return false, errTransactionDone
+	}
+	return tr.db.has(tr.mem.DB, tr.tables, key, tr.seq, ro)
+}
+
+// NewIterator returns an iterator for the latest snapshot of the transaction.
+// The returned iterator is not safe for concurrent use, but it is safe to use
+// multiple iterators concurrently, with each in a dedicated goroutine.
+// It is also safe to use an iterator concurrently while writes to the
+// transaction. The resultant key/value pairs are guaranteed to be consistent.
+//
+// Slice allows slicing the iterator to only contains keys in the given
+// range. A nil Range.Start is treated as a key before all keys in the
+// DB. And a nil Range.Limit is treated as a key after all keys in
+// the DB.
+//
+// The iterator must be released after use, by calling Release method.
+//
+// Also read Iterator documentation of the leveldb/iterator package.
+func (tr *Transaction) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+	tr.lk.RLock()
+	defer tr.lk.RUnlock()
+	if tr.closed {
+		return iterator.NewEmptyIterator(errTransactionDone)
+	}
+	tr.mem.incref()
+	return tr.db.newIterator(tr.mem, tr.tables, tr.seq, slice, ro)
+}
+
+func (tr *Transaction) flush() error {
+	// Flush memdb.
+	if tr.mem.Len() != 0 {
+		tr.stats.startTimer()
+		iter := tr.mem.NewIterator(nil)
+		t, n, err := tr.db.s.tops.createFrom(iter)
+		iter.Release()
+		tr.stats.stopTimer()
+		if err != nil {
+			return err
+		}
+		if tr.mem.getref() == 1 {
+			tr.mem.Reset()
+		} else {
+			tr.mem.decref()
+			tr.mem = tr.db.mpoolGet(0)
+			tr.mem.incref()
+		}
+		tr.tables = append(tr.tables, t)
+		tr.rec.addTableFile(0, t)
+		tr.stats.write += t.size
+		tr.db.logf("transaction@flush created L0@%d N·%d S·%s %q:%q", t.fd.Num, n, shortenb(int(t.size)), t.imin, t.imax)
+	}
+	return nil
+}
+
+func (tr *Transaction) put(kt keyType, key, value []byte) error {
+	tr.ikScratch = makeInternalKey(tr.ikScratch, key, tr.seq+1, kt)
+	if tr.mem.Free() < len(tr.ikScratch)+len(value) {
+		if err := tr.flush(); err != nil {
+			return err
+		}
+	}
+	if err := tr.mem.Put(tr.ikScratch, value); err != nil {
+		return err
+	}
+	tr.seq++
+	return nil
+}
+
+// Put sets the value for the given key. It overwrites any previous value
+// for that key; a DB is not a multi-map.
+// Please note that the transaction is not compacted until committed, so if you
+// writes 10 same keys, then those 10 same keys are in the transaction.
+//
+// It is safe to modify the contents of the arguments after Put returns.
+func (tr *Transaction) Put(key, value []byte, wo *opt.WriteOptions) error {
+	tr.lk.Lock()
+	defer tr.lk.Unlock()
+	if tr.closed {
+		return errTransactionDone
+	}
+	return tr.put(keyTypeVal, key, value)
+}
+
+// Delete deletes the value for the given key.
+// Please note that the transaction is not compacted until committed, so if you
+// writes 10 same keys, then those 10 same keys are in the transaction.
+//
+// It is safe to modify the contents of the arguments after Delete returns.
+func (tr *Transaction) Delete(key []byte, wo *opt.WriteOptions) error {
+	tr.lk.Lock()
+	defer tr.lk.Unlock()
+	if tr.closed {
+		return errTransactionDone
+	}
+	return tr.put(keyTypeDel, key, nil)
+}
+
+// Write apply the given batch to the transaction. The batch will be applied
+// sequentially.
+// Please note that the transaction is not compacted until committed, so if you
+// writes 10 same keys, then those 10 same keys are in the transaction.
+//
+// It is safe to modify the contents of the arguments after Write returns.
+func (tr *Transaction) Write(b *Batch, wo *opt.WriteOptions) error {
+	if b == nil || b.Len() == 0 {
+		return nil
+	}
+
+	tr.lk.Lock()
+	defer tr.lk.Unlock()
+	if tr.closed {
+		return errTransactionDone
+	}
+	return b.replayInternal(func(i int, kt keyType, k, v []byte) error {
+		return tr.put(kt, k, v)
+	})
+}
+
+func (tr *Transaction) setDone() {
+	tr.closed = true
+	tr.db.tr = nil
+	tr.mem.decref()
+	<-tr.db.writeLockC
+}
+
+// Commit commits the transaction. If error is not nil, then the transaction is
+// not committed, it can then either be retried or discarded.
+//
+// Other methods should not be called after transaction has been committed.
+func (tr *Transaction) Commit() error {
+	if err := tr.db.ok(); err != nil {
+		return err
+	}
+
+	tr.lk.Lock()
+	defer tr.lk.Unlock()
+	if tr.closed {
+		return errTransactionDone
+	}
+	if err := tr.flush(); err != nil {
+		// Return error, lets user decide either to retry or discard
+		// transaction.
+		return err
+	}
+	if len(tr.tables) != 0 {
+		// Committing transaction.
+		tr.rec.setSeqNum(tr.seq)
+		tr.db.compCommitLk.Lock()
+		tr.stats.startTimer()
+		var cerr error
+		for retry := 0; retry < 3; retry++ {
+			cerr = tr.db.s.commit(&tr.rec)
+			if cerr != nil {
+				tr.db.logf("transaction@commit error R·%d %q", retry, cerr)
+				select {
+				case <-time.After(time.Second):
+				case <-tr.db.closeC:
+					tr.db.logf("transaction@commit exiting")
+					tr.db.compCommitLk.Unlock()
+					return cerr
+				}
+			} else {
+				// Success. Set db.seq.
+				tr.db.setSeq(tr.seq)
+				break
+			}
+		}
+		tr.stats.stopTimer()
+		if cerr != nil {
+			// Return error, lets user decide either to retry or discard
+			// transaction.
+			return cerr
+		}
+
+		// Update compaction stats. This is safe as long as we hold compCommitLk.
+		tr.db.compStats.addStat(0, &tr.stats)
+
+		// Trigger table auto-compaction.
+		tr.db.compTrigger(tr.db.tcompCmdC)
+		tr.db.compCommitLk.Unlock()
+
+		// Additionally, wait compaction when certain threshold reached.
+		// Ignore error, returns error only if transaction can't be committed.
+		tr.db.waitCompaction()
+	}
+	// Only mark as done if transaction committed successfully.
+	tr.setDone()
+	return nil
+}
+
+func (tr *Transaction) discard() {
+	// Discard transaction.
+	for _, t := range tr.tables {
+		tr.db.logf("transaction@discard @%d", t.fd.Num)
+		if err1 := tr.db.s.stor.Remove(t.fd); err1 == nil {
+			tr.db.s.reuseFileNum(t.fd.Num)
+		}
+	}
+}
+
+// Discard discards the transaction.
+//
+// Other methods should not be called after transaction has been discarded.
+func (tr *Transaction) Discard() {
+	tr.lk.Lock()
+	if !tr.closed {
+		tr.discard()
+		tr.setDone()
+	}
+	tr.lk.Unlock()
+}
+
+func (db *DB) waitCompaction() error {
+	if db.s.tLen(0) >= db.s.o.GetWriteL0PauseTrigger() {
+		return db.compTriggerWait(db.tcompCmdC)
+	}
+	return nil
+}
+
+// OpenTransaction opens an atomic DB transaction. Only one transaction can be
+// opened at a time. Subsequent call to Write and OpenTransaction will be blocked
+// until in-flight transaction is committed or discarded.
+// The returned transaction handle is safe for concurrent use.
+//
+// Transaction is expensive and can overwhelm compaction, especially if
+// transaction size is small. Use with caution.
+//
+// The transaction must be closed once done, either by committing or discarding
+// the transaction.
+// Closing the DB will discard open transaction.
+func (db *DB) OpenTransaction() (*Transaction, error) {
+	if err := db.ok(); err != nil {
+		return nil, err
+	}
+
+	// The write happen synchronously.
+	select {
+	case db.writeLockC <- struct{}{}:
+	case err := <-db.compPerErrC:
+		return nil, err
+	case <-db.closeC:
+		return nil, ErrClosed
+	}
+
+	if db.tr != nil {
+		panic("leveldb: has open transaction")
+	}
+
+	// Flush current memdb.
+	if db.mem != nil && db.mem.Len() != 0 {
+		if _, err := db.rotateMem(0, true); err != nil {
+			return nil, err
+		}
+	}
+
+	// Wait compaction when certain threshold reached.
+	if err := db.waitCompaction(); err != nil {
+		return nil, err
+	}
+
+	tr := &Transaction{
+		db:  db,
+		seq: db.seq,
+		mem: db.mpoolGet(0),
+	}
+	tr.mem.incref()
+	db.tr = tr
+	return tr, nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_util.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_util.go
new file mode 100644
index 0000000000..3f0654894b
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_util.go
@@ -0,0 +1,102 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// Reader is the interface that wraps basic Get and NewIterator methods.
+// This interface implemented by both DB and Snapshot.
+type Reader interface {
+	Get(key []byte, ro *opt.ReadOptions) (value []byte, err error)
+	NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator
+}
+
+// Sizes is list of size.
+type Sizes []int64
+
+// Sum returns sum of the sizes.
+func (sizes Sizes) Sum() int64 {
+	var sum int64
+	for _, size := range sizes {
+		sum += size
+	}
+	return sum
+}
+
+// Logging.
+func (db *DB) log(v ...interface{})                 { db.s.log(v...) }
+func (db *DB) logf(format string, v ...interface{}) { db.s.logf(format, v...) }
+
+// Check and clean files.
+func (db *DB) checkAndCleanFiles() error {
+	v := db.s.version()
+	defer v.release()
+
+	tmap := make(map[int64]bool)
+	for _, tables := range v.levels {
+		for _, t := range tables {
+			tmap[t.fd.Num] = false
+		}
+	}
+
+	fds, err := db.s.stor.List(storage.TypeAll)
+	if err != nil {
+		return err
+	}
+
+	var nt int
+	var rem []storage.FileDesc
+	for _, fd := range fds {
+		keep := true
+		switch fd.Type {
+		case storage.TypeManifest:
+			keep = fd.Num >= db.s.manifestFd.Num
+		case storage.TypeJournal:
+			if !db.frozenJournalFd.Zero() {
+				keep = fd.Num >= db.frozenJournalFd.Num
+			} else {
+				keep = fd.Num >= db.journalFd.Num
+			}
+		case storage.TypeTable:
+			_, keep = tmap[fd.Num]
+			if keep {
+				tmap[fd.Num] = true
+				nt++
+			}
+		}
+
+		if !keep {
+			rem = append(rem, fd)
+		}
+	}
+
+	if nt != len(tmap) {
+		var mfds []storage.FileDesc
+		for num, present := range tmap {
+			if !present {
+				mfds = append(mfds, storage.FileDesc{Type: storage.TypeTable, Num: num})
+				db.logf("db@janitor table missing @%d", num)
+			}
+		}
+		return errors.NewErrCorrupted(storage.FileDesc{}, &errors.ErrMissingFiles{Fds: mfds})
+	}
+
+	db.logf("db@janitor F·%d G·%d", len(fds), len(rem))
+	for _, fd := range rem {
+		db.logf("db@janitor removing %s-%d", fd.Type, fd.Num)
+		if err := db.s.stor.Remove(fd); err != nil {
+			return err
+		}
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/db_write.go b/vendor/github.com/syndtr/goleveldb/leveldb/db_write.go
new file mode 100644
index 0000000000..db0c1bece1
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/db_write.go
@@ -0,0 +1,464 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"sync/atomic"
+	"time"
+
+	"github.com/syndtr/goleveldb/leveldb/memdb"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+func (db *DB) writeJournal(batches []*Batch, seq uint64, sync bool) error {
+	wr, err := db.journal.Next()
+	if err != nil {
+		return err
+	}
+	if err := writeBatchesWithHeader(wr, batches, seq); err != nil {
+		return err
+	}
+	if err := db.journal.Flush(); err != nil {
+		return err
+	}
+	if sync {
+		return db.journalWriter.Sync()
+	}
+	return nil
+}
+
+func (db *DB) rotateMem(n int, wait bool) (mem *memDB, err error) {
+	retryLimit := 3
+retry:
+	// Wait for pending memdb compaction.
+	err = db.compTriggerWait(db.mcompCmdC)
+	if err != nil {
+		return
+	}
+	retryLimit--
+
+	// Create new memdb and journal.
+	mem, err = db.newMem(n)
+	if err != nil {
+		if err == errHasFrozenMem {
+			if retryLimit <= 0 {
+				panic("BUG: still has frozen memdb")
+			}
+			goto retry
+		}
+		return
+	}
+
+	// Schedule memdb compaction.
+	if wait {
+		err = db.compTriggerWait(db.mcompCmdC)
+	} else {
+		db.compTrigger(db.mcompCmdC)
+	}
+	return
+}
+
+func (db *DB) flush(n int) (mdb *memDB, mdbFree int, err error) {
+	delayed := false
+	slowdownTrigger := db.s.o.GetWriteL0SlowdownTrigger()
+	pauseTrigger := db.s.o.GetWriteL0PauseTrigger()
+	flush := func() (retry bool) {
+		mdb = db.getEffectiveMem()
+		if mdb == nil {
+			err = ErrClosed
+			return false
+		}
+		defer func() {
+			if retry {
+				mdb.decref()
+				mdb = nil
+			}
+		}()
+		tLen := db.s.tLen(0)
+		mdbFree = mdb.Free()
+		switch {
+		case tLen >= slowdownTrigger && !delayed:
+			delayed = true
+			time.Sleep(time.Millisecond)
+		case mdbFree >= n:
+			return false
+		case tLen >= pauseTrigger:
+			delayed = true
+			// Set the write paused flag explicitly.
+			atomic.StoreInt32(&db.inWritePaused, 1)
+			err = db.compTriggerWait(db.tcompCmdC)
+			// Unset the write paused flag.
+			atomic.StoreInt32(&db.inWritePaused, 0)
+			if err != nil {
+				return false
+			}
+		default:
+			// Allow memdb to grow if it has no entry.
+			if mdb.Len() == 0 {
+				mdbFree = n
+			} else {
+				mdb.decref()
+				mdb, err = db.rotateMem(n, false)
+				if err == nil {
+					mdbFree = mdb.Free()
+				} else {
+					mdbFree = 0
+				}
+			}
+			return false
+		}
+		return true
+	}
+	start := time.Now()
+	for flush() {
+	}
+	if delayed {
+		db.writeDelay += time.Since(start)
+		db.writeDelayN++
+	} else if db.writeDelayN > 0 {
+		db.logf("db@write was delayed N·%d T·%v", db.writeDelayN, db.writeDelay)
+		atomic.AddInt32(&db.cWriteDelayN, int32(db.writeDelayN))
+		atomic.AddInt64(&db.cWriteDelay, int64(db.writeDelay))
+		db.writeDelay = 0
+		db.writeDelayN = 0
+	}
+	return
+}
+
+type writeMerge struct {
+	sync       bool
+	batch      *Batch
+	keyType    keyType
+	key, value []byte
+}
+
+func (db *DB) unlockWrite(overflow bool, merged int, err error) {
+	for i := 0; i < merged; i++ {
+		db.writeAckC <- err
+	}
+	if overflow {
+		// Pass lock to the next write (that failed to merge).
+		db.writeMergedC <- false
+	} else {
+		// Release lock.
+		<-db.writeLockC
+	}
+}
+
+// ourBatch is batch that we can modify.
+func (db *DB) writeLocked(batch, ourBatch *Batch, merge, sync bool) error {
+	// Try to flush memdb. This method would also trying to throttle writes
+	// if it is too fast and compaction cannot catch-up.
+	mdb, mdbFree, err := db.flush(batch.internalLen)
+	if err != nil {
+		db.unlockWrite(false, 0, err)
+		return err
+	}
+	defer mdb.decref()
+
+	var (
+		overflow bool
+		merged   int
+		batches  = []*Batch{batch}
+	)
+
+	if merge {
+		// Merge limit.
+		var mergeLimit int
+		if batch.internalLen > 128<<10 {
+			mergeLimit = (1 << 20) - batch.internalLen
+		} else {
+			mergeLimit = 128 << 10
+		}
+		mergeCap := mdbFree - batch.internalLen
+		if mergeLimit > mergeCap {
+			mergeLimit = mergeCap
+		}
+
+	merge:
+		for mergeLimit > 0 {
+			select {
+			case incoming := <-db.writeMergeC:
+				if incoming.batch != nil {
+					// Merge batch.
+					if incoming.batch.internalLen > mergeLimit {
+						overflow = true
+						break merge
+					}
+					batches = append(batches, incoming.batch)
+					mergeLimit -= incoming.batch.internalLen
+				} else {
+					// Merge put.
+					internalLen := len(incoming.key) + len(incoming.value) + 8
+					if internalLen > mergeLimit {
+						overflow = true
+						break merge
+					}
+					if ourBatch == nil {
+						ourBatch = db.batchPool.Get().(*Batch)
+						ourBatch.Reset()
+						batches = append(batches, ourBatch)
+					}
+					// We can use same batch since concurrent write doesn't
+					// guarantee write order.
+					ourBatch.appendRec(incoming.keyType, incoming.key, incoming.value)
+					mergeLimit -= internalLen
+				}
+				sync = sync || incoming.sync
+				merged++
+				db.writeMergedC <- true
+
+			default:
+				break merge
+			}
+		}
+	}
+
+	// Release ourBatch if any.
+	if ourBatch != nil {
+		defer db.batchPool.Put(ourBatch)
+	}
+
+	// Seq number.
+	seq := db.seq + 1
+
+	// Write journal.
+	if err := db.writeJournal(batches, seq, sync); err != nil {
+		db.unlockWrite(overflow, merged, err)
+		return err
+	}
+
+	// Put batches.
+	for _, batch := range batches {
+		if err := batch.putMem(seq, mdb.DB); err != nil {
+			panic(err)
+		}
+		seq += uint64(batch.Len())
+	}
+
+	// Incr seq number.
+	db.addSeq(uint64(batchesLen(batches)))
+
+	// Rotate memdb if it's reach the threshold.
+	if batch.internalLen >= mdbFree {
+		db.rotateMem(0, false)
+	}
+
+	db.unlockWrite(overflow, merged, nil)
+	return nil
+}
+
+// Write apply the given batch to the DB. The batch records will be applied
+// sequentially. Write might be used concurrently, when used concurrently and
+// batch is small enough, write will try to merge the batches. Set NoWriteMerge
+// option to true to disable write merge.
+//
+// It is safe to modify the contents of the arguments after Write returns but
+// not before. Write will not modify content of the batch.
+func (db *DB) Write(batch *Batch, wo *opt.WriteOptions) error {
+	if err := db.ok(); err != nil || batch == nil || batch.Len() == 0 {
+		return err
+	}
+
+	// If the batch size is larger than write buffer, it may justified to write
+	// using transaction instead. Using transaction the batch will be written
+	// into tables directly, skipping the journaling.
+	if batch.internalLen > db.s.o.GetWriteBuffer() && !db.s.o.GetDisableLargeBatchTransaction() {
+		tr, err := db.OpenTransaction()
+		if err != nil {
+			return err
+		}
+		if err := tr.Write(batch, wo); err != nil {
+			tr.Discard()
+			return err
+		}
+		return tr.Commit()
+	}
+
+	merge := !wo.GetNoWriteMerge() && !db.s.o.GetNoWriteMerge()
+	sync := wo.GetSync() && !db.s.o.GetNoSync()
+
+	// Acquire write lock.
+	if merge {
+		select {
+		case db.writeMergeC <- writeMerge{sync: sync, batch: batch}:
+			if <-db.writeMergedC {
+				// Write is merged.
+				return <-db.writeAckC
+			}
+			// Write is not merged, the write lock is handed to us. Continue.
+		case db.writeLockC <- struct{}{}:
+			// Write lock acquired.
+		case err := <-db.compPerErrC:
+			// Compaction error.
+			return err
+		case <-db.closeC:
+			// Closed
+			return ErrClosed
+		}
+	} else {
+		select {
+		case db.writeLockC <- struct{}{}:
+			// Write lock acquired.
+		case err := <-db.compPerErrC:
+			// Compaction error.
+			return err
+		case <-db.closeC:
+			// Closed
+			return ErrClosed
+		}
+	}
+
+	return db.writeLocked(batch, nil, merge, sync)
+}
+
+func (db *DB) putRec(kt keyType, key, value []byte, wo *opt.WriteOptions) error {
+	if err := db.ok(); err != nil {
+		return err
+	}
+
+	merge := !wo.GetNoWriteMerge() && !db.s.o.GetNoWriteMerge()
+	sync := wo.GetSync() && !db.s.o.GetNoSync()
+
+	// Acquire write lock.
+	if merge {
+		select {
+		case db.writeMergeC <- writeMerge{sync: sync, keyType: kt, key: key, value: value}:
+			if <-db.writeMergedC {
+				// Write is merged.
+				return <-db.writeAckC
+			}
+			// Write is not merged, the write lock is handed to us. Continue.
+		case db.writeLockC <- struct{}{}:
+			// Write lock acquired.
+		case err := <-db.compPerErrC:
+			// Compaction error.
+			return err
+		case <-db.closeC:
+			// Closed
+			return ErrClosed
+		}
+	} else {
+		select {
+		case db.writeLockC <- struct{}{}:
+			// Write lock acquired.
+		case err := <-db.compPerErrC:
+			// Compaction error.
+			return err
+		case <-db.closeC:
+			// Closed
+			return ErrClosed
+		}
+	}
+
+	batch := db.batchPool.Get().(*Batch)
+	batch.Reset()
+	batch.appendRec(kt, key, value)
+	return db.writeLocked(batch, batch, merge, sync)
+}
+
+// Put sets the value for the given key. It overwrites any previous value
+// for that key; a DB is not a multi-map. Write merge also applies for Put, see
+// Write.
+//
+// It is safe to modify the contents of the arguments after Put returns but not
+// before.
+func (db *DB) Put(key, value []byte, wo *opt.WriteOptions) error {
+	return db.putRec(keyTypeVal, key, value, wo)
+}
+
+// Delete deletes the value for the given key. Delete will not returns error if
+// key doesn't exist. Write merge also applies for Delete, see Write.
+//
+// It is safe to modify the contents of the arguments after Delete returns but
+// not before.
+func (db *DB) Delete(key []byte, wo *opt.WriteOptions) error {
+	return db.putRec(keyTypeDel, key, nil, wo)
+}
+
+func isMemOverlaps(icmp *iComparer, mem *memdb.DB, min, max []byte) bool {
+	iter := mem.NewIterator(nil)
+	defer iter.Release()
+	return (max == nil || (iter.First() && icmp.uCompare(max, internalKey(iter.Key()).ukey()) >= 0)) &&
+		(min == nil || (iter.Last() && icmp.uCompare(min, internalKey(iter.Key()).ukey()) <= 0))
+}
+
+// CompactRange compacts the underlying DB for the given key range.
+// In particular, deleted and overwritten versions are discarded,
+// and the data is rearranged to reduce the cost of operations
+// needed to access the data. This operation should typically only
+// be invoked by users who understand the underlying implementation.
+//
+// A nil Range.Start is treated as a key before all keys in the DB.
+// And a nil Range.Limit is treated as a key after all keys in the DB.
+// Therefore if both is nil then it will compact entire DB.
+func (db *DB) CompactRange(r util.Range) error {
+	if err := db.ok(); err != nil {
+		return err
+	}
+
+	// Lock writer.
+	select {
+	case db.writeLockC <- struct{}{}:
+	case err := <-db.compPerErrC:
+		return err
+	case <-db.closeC:
+		return ErrClosed
+	}
+
+	// Check for overlaps in memdb.
+	mdb := db.getEffectiveMem()
+	if mdb == nil {
+		return ErrClosed
+	}
+	defer mdb.decref()
+	if isMemOverlaps(db.s.icmp, mdb.DB, r.Start, r.Limit) {
+		// Memdb compaction.
+		if _, err := db.rotateMem(0, false); err != nil {
+			<-db.writeLockC
+			return err
+		}
+		<-db.writeLockC
+		if err := db.compTriggerWait(db.mcompCmdC); err != nil {
+			return err
+		}
+	} else {
+		<-db.writeLockC
+	}
+
+	// Table compaction.
+	return db.compTriggerRange(db.tcompCmdC, -1, r.Start, r.Limit)
+}
+
+// SetReadOnly makes DB read-only. It will stay read-only until reopened.
+func (db *DB) SetReadOnly() error {
+	if err := db.ok(); err != nil {
+		return err
+	}
+
+	// Lock writer.
+	select {
+	case db.writeLockC <- struct{}{}:
+		db.compWriteLocking = true
+	case err := <-db.compPerErrC:
+		return err
+	case <-db.closeC:
+		return ErrClosed
+	}
+
+	// Set compaction read-only.
+	select {
+	case db.compErrSetC <- ErrReadOnly:
+	case perr := <-db.compPerErrC:
+		return perr
+	case <-db.closeC:
+		return ErrClosed
+	}
+
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/doc.go b/vendor/github.com/syndtr/goleveldb/leveldb/doc.go
new file mode 100644
index 0000000000..be768e5739
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/doc.go
@@ -0,0 +1,92 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package leveldb provides implementation of LevelDB key/value database.
+//
+// Create or open a database:
+//
+//	// The returned DB instance is safe for concurrent use. Which mean that all
+//	// DB's methods may be called concurrently from multiple goroutine.
+//	db, err := leveldb.OpenFile("path/to/db", nil)
+//	...
+//	defer db.Close()
+//	...
+//
+// Read or modify the database content:
+//
+//	// Remember that the contents of the returned slice should not be modified.
+//	data, err := db.Get([]byte("key"), nil)
+//	...
+//	err = db.Put([]byte("key"), []byte("value"), nil)
+//	...
+//	err = db.Delete([]byte("key"), nil)
+//	...
+//
+// Iterate over database content:
+//
+//	iter := db.NewIterator(nil, nil)
+//	for iter.Next() {
+//		// Remember that the contents of the returned slice should not be modified, and
+//		// only valid until the next call to Next.
+//		key := iter.Key()
+//		value := iter.Value()
+//		...
+//	}
+//	iter.Release()
+//	err = iter.Error()
+//	...
+//
+// Iterate over subset of database content with a particular prefix:
+//	iter := db.NewIterator(util.BytesPrefix([]byte("foo-")), nil)
+//	for iter.Next() {
+//		// Use key/value.
+//		...
+//	}
+//	iter.Release()
+//	err = iter.Error()
+//	...
+//
+// Seek-then-Iterate:
+//
+// 	iter := db.NewIterator(nil, nil)
+// 	for ok := iter.Seek(key); ok; ok = iter.Next() {
+// 		// Use key/value.
+// 		...
+// 	}
+// 	iter.Release()
+// 	err = iter.Error()
+// 	...
+//
+// Iterate over subset of database content:
+//
+// 	iter := db.NewIterator(&util.Range{Start: []byte("foo"), Limit: []byte("xoo")}, nil)
+// 	for iter.Next() {
+// 		// Use key/value.
+// 		...
+// 	}
+// 	iter.Release()
+// 	err = iter.Error()
+// 	...
+//
+// Batch writes:
+//
+//	batch := new(leveldb.Batch)
+//	batch.Put([]byte("foo"), []byte("value"))
+//	batch.Put([]byte("bar"), []byte("another value"))
+//	batch.Delete([]byte("baz"))
+//	err = db.Write(batch, nil)
+//	...
+//
+// Use bloom filter:
+//
+//	o := &opt.Options{
+//		Filter: filter.NewBloomFilter(10),
+//	}
+//	db, err := leveldb.OpenFile("path/to/db", o)
+//	...
+//	defer db.Close()
+//	...
+package leveldb
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/errors.go b/vendor/github.com/syndtr/goleveldb/leveldb/errors.go
new file mode 100644
index 0000000000..de2649812c
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/errors.go
@@ -0,0 +1,20 @@
+// Copyright (c) 2014, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/errors"
+)
+
+// Common errors.
+var (
+	ErrNotFound         = errors.ErrNotFound
+	ErrReadOnly         = errors.New("leveldb: read-only mode")
+	ErrSnapshotReleased = errors.New("leveldb: snapshot released")
+	ErrIterReleased     = errors.New("leveldb: iterator released")
+	ErrClosed           = errors.New("leveldb: closed")
+)
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/errors/errors.go b/vendor/github.com/syndtr/goleveldb/leveldb/errors/errors.go
new file mode 100644
index 0000000000..8d6146b6f5
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/errors/errors.go
@@ -0,0 +1,78 @@
+// Copyright (c) 2014, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package errors provides common error types used throughout leveldb.
+package errors
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// Common errors.
+var (
+	ErrNotFound    = New("leveldb: not found")
+	ErrReleased    = util.ErrReleased
+	ErrHasReleaser = util.ErrHasReleaser
+)
+
+// New returns an error that formats as the given text.
+func New(text string) error {
+	return errors.New(text)
+}
+
+// ErrCorrupted is the type that wraps errors that indicate corruption in
+// the database.
+type ErrCorrupted struct {
+	Fd  storage.FileDesc
+	Err error
+}
+
+func (e *ErrCorrupted) Error() string {
+	if !e.Fd.Zero() {
+		return fmt.Sprintf("%v [file=%v]", e.Err, e.Fd)
+	}
+	return e.Err.Error()
+}
+
+// NewErrCorrupted creates new ErrCorrupted error.
+func NewErrCorrupted(fd storage.FileDesc, err error) error {
+	return &ErrCorrupted{fd, err}
+}
+
+// IsCorrupted returns a boolean indicating whether the error is indicating
+// a corruption.
+func IsCorrupted(err error) bool {
+	switch err.(type) {
+	case *ErrCorrupted:
+		return true
+	case *storage.ErrCorrupted:
+		return true
+	}
+	return false
+}
+
+// ErrMissingFiles is the type that indicating a corruption due to missing
+// files. ErrMissingFiles always wrapped with ErrCorrupted.
+type ErrMissingFiles struct {
+	Fds []storage.FileDesc
+}
+
+func (e *ErrMissingFiles) Error() string { return "file missing" }
+
+// SetFd sets 'file info' of the given error with the given file.
+// Currently only ErrCorrupted is supported, otherwise will do nothing.
+func SetFd(err error, fd storage.FileDesc) error {
+	switch x := err.(type) {
+	case *ErrCorrupted:
+		x.Fd = fd
+		return x
+	}
+	return err
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/filter.go b/vendor/github.com/syndtr/goleveldb/leveldb/filter.go
new file mode 100644
index 0000000000..e961e420d3
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/filter.go
@@ -0,0 +1,31 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/filter"
+)
+
+type iFilter struct {
+	filter.Filter
+}
+
+func (f iFilter) Contains(filter, key []byte) bool {
+	return f.Filter.Contains(filter, internalKey(key).ukey())
+}
+
+func (f iFilter) NewGenerator() filter.FilterGenerator {
+	return iFilterGenerator{f.Filter.NewGenerator()}
+}
+
+type iFilterGenerator struct {
+	filter.FilterGenerator
+}
+
+func (g iFilterGenerator) Add(key []byte) {
+	g.FilterGenerator.Add(internalKey(key).ukey())
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/filter/bloom.go b/vendor/github.com/syndtr/goleveldb/leveldb/filter/bloom.go
new file mode 100644
index 0000000000..bab0e99705
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/filter/bloom.go
@@ -0,0 +1,116 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package filter
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+func bloomHash(key []byte) uint32 {
+	return util.Hash(key, 0xbc9f1d34)
+}
+
+type bloomFilter int
+
+// The bloom filter serializes its parameters and is backward compatible
+// with respect to them. Therefor, its parameters are not added to its
+// name.
+func (bloomFilter) Name() string {
+	return "leveldb.BuiltinBloomFilter"
+}
+
+func (f bloomFilter) Contains(filter, key []byte) bool {
+	nBytes := len(filter) - 1
+	if nBytes < 1 {
+		return false
+	}
+	nBits := uint32(nBytes * 8)
+
+	// Use the encoded k so that we can read filters generated by
+	// bloom filters created using different parameters.
+	k := filter[nBytes]
+	if k > 30 {
+		// Reserved for potentially new encodings for short bloom filters.
+		// Consider it a match.
+		return true
+	}
+
+	kh := bloomHash(key)
+	delta := (kh >> 17) | (kh << 15) // Rotate right 17 bits
+	for j := uint8(0); j < k; j++ {
+		bitpos := kh % nBits
+		if (uint32(filter[bitpos/8]) & (1 << (bitpos % 8))) == 0 {
+			return false
+		}
+		kh += delta
+	}
+	return true
+}
+
+func (f bloomFilter) NewGenerator() FilterGenerator {
+	// Round down to reduce probing cost a little bit.
+	k := uint8(f * 69 / 100) // 0.69 =~ ln(2)
+	if k < 1 {
+		k = 1
+	} else if k > 30 {
+		k = 30
+	}
+	return &bloomFilterGenerator{
+		n: int(f),
+		k: k,
+	}
+}
+
+type bloomFilterGenerator struct {
+	n int
+	k uint8
+
+	keyHashes []uint32
+}
+
+func (g *bloomFilterGenerator) Add(key []byte) {
+	// Use double-hashing to generate a sequence of hash values.
+	// See analysis in [Kirsch,Mitzenmacher 2006].
+	g.keyHashes = append(g.keyHashes, bloomHash(key))
+}
+
+func (g *bloomFilterGenerator) Generate(b Buffer) {
+	// Compute bloom filter size (in both bits and bytes)
+	nBits := uint32(len(g.keyHashes) * g.n)
+	// For small n, we can see a very high false positive rate.  Fix it
+	// by enforcing a minimum bloom filter length.
+	if nBits < 64 {
+		nBits = 64
+	}
+	nBytes := (nBits + 7) / 8
+	nBits = nBytes * 8
+
+	dest := b.Alloc(int(nBytes) + 1)
+	dest[nBytes] = g.k
+	for _, kh := range g.keyHashes {
+		delta := (kh >> 17) | (kh << 15) // Rotate right 17 bits
+		for j := uint8(0); j < g.k; j++ {
+			bitpos := kh % nBits
+			dest[bitpos/8] |= (1 << (bitpos % 8))
+			kh += delta
+		}
+	}
+
+	g.keyHashes = g.keyHashes[:0]
+}
+
+// NewBloomFilter creates a new initialized bloom filter for given
+// bitsPerKey.
+//
+// Since bitsPerKey is persisted individually for each bloom filter
+// serialization, bloom filters are backwards compatible with respect to
+// changing bitsPerKey. This means that no big performance penalty will
+// be experienced when changing the parameter. See documentation for
+// opt.Options.Filter for more information.
+func NewBloomFilter(bitsPerKey int) Filter {
+	return bloomFilter(bitsPerKey)
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/filter/filter.go b/vendor/github.com/syndtr/goleveldb/leveldb/filter/filter.go
new file mode 100644
index 0000000000..7a925c5a86
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/filter/filter.go
@@ -0,0 +1,60 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package filter provides interface and implementation of probabilistic
+// data structure.
+//
+// The filter is resposible for creating small filter from a set of keys.
+// These filter will then used to test whether a key is a member of the set.
+// In many cases, a filter can cut down the number of disk seeks from a
+// handful to a single disk seek per DB.Get call.
+package filter
+
+// Buffer is the interface that wraps basic Alloc, Write and WriteByte methods.
+type Buffer interface {
+	// Alloc allocs n bytes of slice from the buffer. This also advancing
+	// write offset.
+	Alloc(n int) []byte
+
+	// Write appends the contents of p to the buffer.
+	Write(p []byte) (n int, err error)
+
+	// WriteByte appends the byte c to the buffer.
+	WriteByte(c byte) error
+}
+
+// Filter is the filter.
+type Filter interface {
+	// Name returns the name of this policy.
+	//
+	// Note that if the filter encoding changes in an incompatible way,
+	// the name returned by this method must be changed. Otherwise, old
+	// incompatible filters may be passed to methods of this type.
+	Name() string
+
+	// NewGenerator creates a new filter generator.
+	NewGenerator() FilterGenerator
+
+	// Contains returns true if the filter contains the given key.
+	//
+	// The filter are filters generated by the filter generator.
+	Contains(filter, key []byte) bool
+}
+
+// FilterGenerator is the filter generator.
+type FilterGenerator interface {
+	// Add adds a key to the filter generator.
+	//
+	// The key may become invalid after call to this method end, therefor
+	// key must be copied if implementation require keeping key for later
+	// use. The key should not modified directly, doing so may cause
+	// undefined results.
+	Add(key []byte)
+
+	// Generate generates filters based on keys passed so far. After call
+	// to Generate the filter generator maybe resetted, depends on implementation.
+	Generate(b Buffer)
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go
new file mode 100644
index 0000000000..a23ab05f70
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/array_iter.go
@@ -0,0 +1,184 @@
+// Copyright (c) 2014, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package iterator
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// BasicArray is the interface that wraps basic Len and Search method.
+type BasicArray interface {
+	// Len returns length of the array.
+	Len() int
+
+	// Search finds smallest index that point to a key that is greater
+	// than or equal to the given key.
+	Search(key []byte) int
+}
+
+// Array is the interface that wraps BasicArray and basic Index method.
+type Array interface {
+	BasicArray
+
+	// Index returns key/value pair with index of i.
+	Index(i int) (key, value []byte)
+}
+
+// Array is the interface that wraps BasicArray and basic Get method.
+type ArrayIndexer interface {
+	BasicArray
+
+	// Get returns a new data iterator with index of i.
+	Get(i int) Iterator
+}
+
+type basicArrayIterator struct {
+	util.BasicReleaser
+	array BasicArray
+	pos   int
+	err   error
+}
+
+func (i *basicArrayIterator) Valid() bool {
+	return i.pos >= 0 && i.pos < i.array.Len() && !i.Released()
+}
+
+func (i *basicArrayIterator) First() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.array.Len() == 0 {
+		i.pos = -1
+		return false
+	}
+	i.pos = 0
+	return true
+}
+
+func (i *basicArrayIterator) Last() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	n := i.array.Len()
+	if n == 0 {
+		i.pos = 0
+		return false
+	}
+	i.pos = n - 1
+	return true
+}
+
+func (i *basicArrayIterator) Seek(key []byte) bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	n := i.array.Len()
+	if n == 0 {
+		i.pos = 0
+		return false
+	}
+	i.pos = i.array.Search(key)
+	if i.pos >= n {
+		return false
+	}
+	return true
+}
+
+func (i *basicArrayIterator) Next() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	i.pos++
+	if n := i.array.Len(); i.pos >= n {
+		i.pos = n
+		return false
+	}
+	return true
+}
+
+func (i *basicArrayIterator) Prev() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	i.pos--
+	if i.pos < 0 {
+		i.pos = -1
+		return false
+	}
+	return true
+}
+
+func (i *basicArrayIterator) Error() error { return i.err }
+
+type arrayIterator struct {
+	basicArrayIterator
+	array      Array
+	pos        int
+	key, value []byte
+}
+
+func (i *arrayIterator) updateKV() {
+	if i.pos == i.basicArrayIterator.pos {
+		return
+	}
+	i.pos = i.basicArrayIterator.pos
+	if i.Valid() {
+		i.key, i.value = i.array.Index(i.pos)
+	} else {
+		i.key = nil
+		i.value = nil
+	}
+}
+
+func (i *arrayIterator) Key() []byte {
+	i.updateKV()
+	return i.key
+}
+
+func (i *arrayIterator) Value() []byte {
+	i.updateKV()
+	return i.value
+}
+
+type arrayIteratorIndexer struct {
+	basicArrayIterator
+	array ArrayIndexer
+}
+
+func (i *arrayIteratorIndexer) Get() Iterator {
+	if i.Valid() {
+		return i.array.Get(i.basicArrayIterator.pos)
+	}
+	return nil
+}
+
+// NewArrayIterator returns an iterator from the given array.
+func NewArrayIterator(array Array) Iterator {
+	return &arrayIterator{
+		basicArrayIterator: basicArrayIterator{array: array, pos: -1},
+		array:              array,
+		pos:                -1,
+	}
+}
+
+// NewArrayIndexer returns an index iterator from the given array.
+func NewArrayIndexer(array ArrayIndexer) IteratorIndexer {
+	return &arrayIteratorIndexer{
+		basicArrayIterator: basicArrayIterator{array: array, pos: -1},
+		array:              array,
+	}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/iterator/indexed_iter.go b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/indexed_iter.go
new file mode 100644
index 0000000000..939adbb933
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/indexed_iter.go
@@ -0,0 +1,242 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package iterator
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// IteratorIndexer is the interface that wraps CommonIterator and basic Get
+// method. IteratorIndexer provides index for indexed iterator.
+type IteratorIndexer interface {
+	CommonIterator
+
+	// Get returns a new data iterator for the current position, or nil if
+	// done.
+	Get() Iterator
+}
+
+type indexedIterator struct {
+	util.BasicReleaser
+	index  IteratorIndexer
+	strict bool
+
+	data   Iterator
+	err    error
+	errf   func(err error)
+	closed bool
+}
+
+func (i *indexedIterator) setData() {
+	if i.data != nil {
+		i.data.Release()
+	}
+	i.data = i.index.Get()
+}
+
+func (i *indexedIterator) clearData() {
+	if i.data != nil {
+		i.data.Release()
+	}
+	i.data = nil
+}
+
+func (i *indexedIterator) indexErr() {
+	if err := i.index.Error(); err != nil {
+		if i.errf != nil {
+			i.errf(err)
+		}
+		i.err = err
+	}
+}
+
+func (i *indexedIterator) dataErr() bool {
+	if err := i.data.Error(); err != nil {
+		if i.errf != nil {
+			i.errf(err)
+		}
+		if i.strict || !errors.IsCorrupted(err) {
+			i.err = err
+			return true
+		}
+	}
+	return false
+}
+
+func (i *indexedIterator) Valid() bool {
+	return i.data != nil && i.data.Valid()
+}
+
+func (i *indexedIterator) First() bool {
+	if i.err != nil {
+		return false
+	} else if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if !i.index.First() {
+		i.indexErr()
+		i.clearData()
+		return false
+	}
+	i.setData()
+	return i.Next()
+}
+
+func (i *indexedIterator) Last() bool {
+	if i.err != nil {
+		return false
+	} else if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if !i.index.Last() {
+		i.indexErr()
+		i.clearData()
+		return false
+	}
+	i.setData()
+	if !i.data.Last() {
+		if i.dataErr() {
+			return false
+		}
+		i.clearData()
+		return i.Prev()
+	}
+	return true
+}
+
+func (i *indexedIterator) Seek(key []byte) bool {
+	if i.err != nil {
+		return false
+	} else if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if !i.index.Seek(key) {
+		i.indexErr()
+		i.clearData()
+		return false
+	}
+	i.setData()
+	if !i.data.Seek(key) {
+		if i.dataErr() {
+			return false
+		}
+		i.clearData()
+		return i.Next()
+	}
+	return true
+}
+
+func (i *indexedIterator) Next() bool {
+	if i.err != nil {
+		return false
+	} else if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	switch {
+	case i.data != nil && !i.data.Next():
+		if i.dataErr() {
+			return false
+		}
+		i.clearData()
+		fallthrough
+	case i.data == nil:
+		if !i.index.Next() {
+			i.indexErr()
+			return false
+		}
+		i.setData()
+		return i.Next()
+	}
+	return true
+}
+
+func (i *indexedIterator) Prev() bool {
+	if i.err != nil {
+		return false
+	} else if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	switch {
+	case i.data != nil && !i.data.Prev():
+		if i.dataErr() {
+			return false
+		}
+		i.clearData()
+		fallthrough
+	case i.data == nil:
+		if !i.index.Prev() {
+			i.indexErr()
+			return false
+		}
+		i.setData()
+		if !i.data.Last() {
+			if i.dataErr() {
+				return false
+			}
+			i.clearData()
+			return i.Prev()
+		}
+	}
+	return true
+}
+
+func (i *indexedIterator) Key() []byte {
+	if i.data == nil {
+		return nil
+	}
+	return i.data.Key()
+}
+
+func (i *indexedIterator) Value() []byte {
+	if i.data == nil {
+		return nil
+	}
+	return i.data.Value()
+}
+
+func (i *indexedIterator) Release() {
+	i.clearData()
+	i.index.Release()
+	i.BasicReleaser.Release()
+}
+
+func (i *indexedIterator) Error() error {
+	if i.err != nil {
+		return i.err
+	}
+	if err := i.index.Error(); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (i *indexedIterator) SetErrorCallback(f func(err error)) {
+	i.errf = f
+}
+
+// NewIndexedIterator returns an 'indexed iterator'. An index is iterator
+// that returns another iterator, a 'data iterator'. A 'data iterator' is the
+// iterator that contains actual key/value pairs.
+//
+// If strict is true the any 'corruption errors' (i.e errors.IsCorrupted(err) == true)
+// won't be ignored and will halt 'indexed iterator', otherwise the iterator will
+// continue to the next 'data iterator'. Corruption on 'index iterator' will not be
+// ignored and will halt the iterator.
+func NewIndexedIterator(index IteratorIndexer, strict bool) Iterator {
+	return &indexedIterator{index: index, strict: strict}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/iterator/iter.go b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/iter.go
new file mode 100644
index 0000000000..96fb0f6859
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/iter.go
@@ -0,0 +1,132 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package iterator provides interface and implementation to traverse over
+// contents of a database.
+package iterator
+
+import (
+	"errors"
+
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+var (
+	ErrIterReleased = errors.New("leveldb/iterator: iterator released")
+)
+
+// IteratorSeeker is the interface that wraps the 'seeks method'.
+type IteratorSeeker interface {
+	// First moves the iterator to the first key/value pair. If the iterator
+	// only contains one key/value pair then First and Last would moves
+	// to the same key/value pair.
+	// It returns whether such pair exist.
+	First() bool
+
+	// Last moves the iterator to the last key/value pair. If the iterator
+	// only contains one key/value pair then First and Last would moves
+	// to the same key/value pair.
+	// It returns whether such pair exist.
+	Last() bool
+
+	// Seek moves the iterator to the first key/value pair whose key is greater
+	// than or equal to the given key.
+	// It returns whether such pair exist.
+	//
+	// It is safe to modify the contents of the argument after Seek returns.
+	Seek(key []byte) bool
+
+	// Next moves the iterator to the next key/value pair.
+	// It returns false if the iterator is exhausted.
+	Next() bool
+
+	// Prev moves the iterator to the previous key/value pair.
+	// It returns false if the iterator is exhausted.
+	Prev() bool
+}
+
+// CommonIterator is the interface that wraps common iterator methods.
+type CommonIterator interface {
+	IteratorSeeker
+
+	// util.Releaser is the interface that wraps basic Release method.
+	// When called Release will releases any resources associated with the
+	// iterator.
+	util.Releaser
+
+	// util.ReleaseSetter is the interface that wraps the basic SetReleaser
+	// method.
+	util.ReleaseSetter
+
+	// TODO: Remove this when ready.
+	Valid() bool
+
+	// Error returns any accumulated error. Exhausting all the key/value pairs
+	// is not considered to be an error.
+	Error() error
+}
+
+// Iterator iterates over a DB's key/value pairs in key order.
+//
+// When encounter an error any 'seeks method' will return false and will
+// yield no key/value pairs. The error can be queried by calling the Error
+// method. Calling Release is still necessary.
+//
+// An iterator must be released after use, but it is not necessary to read
+// an iterator until exhaustion.
+// Also, an iterator is not necessarily safe for concurrent use, but it is
+// safe to use multiple iterators concurrently, with each in a dedicated
+// goroutine.
+type Iterator interface {
+	CommonIterator
+
+	// Key returns the key of the current key/value pair, or nil if done.
+	// The caller should not modify the contents of the returned slice, and
+	// its contents may change on the next call to any 'seeks method'.
+	Key() []byte
+
+	// Value returns the value of the current key/value pair, or nil if done.
+	// The caller should not modify the contents of the returned slice, and
+	// its contents may change on the next call to any 'seeks method'.
+	Value() []byte
+}
+
+// ErrorCallbackSetter is the interface that wraps basic SetErrorCallback
+// method.
+//
+// ErrorCallbackSetter implemented by indexed and merged iterator.
+type ErrorCallbackSetter interface {
+	// SetErrorCallback allows set an error callback of the corresponding
+	// iterator. Use nil to clear the callback.
+	SetErrorCallback(f func(err error))
+}
+
+type emptyIterator struct {
+	util.BasicReleaser
+	err error
+}
+
+func (i *emptyIterator) rErr() {
+	if i.err == nil && i.Released() {
+		i.err = ErrIterReleased
+	}
+}
+
+func (*emptyIterator) Valid() bool            { return false }
+func (i *emptyIterator) First() bool          { i.rErr(); return false }
+func (i *emptyIterator) Last() bool           { i.rErr(); return false }
+func (i *emptyIterator) Seek(key []byte) bool { i.rErr(); return false }
+func (i *emptyIterator) Next() bool           { i.rErr(); return false }
+func (i *emptyIterator) Prev() bool           { i.rErr(); return false }
+func (*emptyIterator) Key() []byte            { return nil }
+func (*emptyIterator) Value() []byte          { return nil }
+func (i *emptyIterator) Error() error         { return i.err }
+
+// NewEmptyIterator creates an empty iterator. The err parameter can be
+// nil, but if not nil the given err will be returned by Error method.
+func NewEmptyIterator(err error) Iterator {
+	return &emptyIterator{err: err}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/iterator/merged_iter.go b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/merged_iter.go
new file mode 100644
index 0000000000..1a7e29df8f
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/iterator/merged_iter.go
@@ -0,0 +1,304 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package iterator
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/comparer"
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+type dir int
+
+const (
+	dirReleased dir = iota - 1
+	dirSOI
+	dirEOI
+	dirBackward
+	dirForward
+)
+
+type mergedIterator struct {
+	cmp    comparer.Comparer
+	iters  []Iterator
+	strict bool
+
+	keys     [][]byte
+	index    int
+	dir      dir
+	err      error
+	errf     func(err error)
+	releaser util.Releaser
+}
+
+func assertKey(key []byte) []byte {
+	if key == nil {
+		panic("leveldb/iterator: nil key")
+	}
+	return key
+}
+
+func (i *mergedIterator) iterErr(iter Iterator) bool {
+	if err := iter.Error(); err != nil {
+		if i.errf != nil {
+			i.errf(err)
+		}
+		if i.strict || !errors.IsCorrupted(err) {
+			i.err = err
+			return true
+		}
+	}
+	return false
+}
+
+func (i *mergedIterator) Valid() bool {
+	return i.err == nil && i.dir > dirEOI
+}
+
+func (i *mergedIterator) First() bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	for x, iter := range i.iters {
+		switch {
+		case iter.First():
+			i.keys[x] = assertKey(iter.Key())
+		case i.iterErr(iter):
+			return false
+		default:
+			i.keys[x] = nil
+		}
+	}
+	i.dir = dirSOI
+	return i.next()
+}
+
+func (i *mergedIterator) Last() bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	for x, iter := range i.iters {
+		switch {
+		case iter.Last():
+			i.keys[x] = assertKey(iter.Key())
+		case i.iterErr(iter):
+			return false
+		default:
+			i.keys[x] = nil
+		}
+	}
+	i.dir = dirEOI
+	return i.prev()
+}
+
+func (i *mergedIterator) Seek(key []byte) bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	for x, iter := range i.iters {
+		switch {
+		case iter.Seek(key):
+			i.keys[x] = assertKey(iter.Key())
+		case i.iterErr(iter):
+			return false
+		default:
+			i.keys[x] = nil
+		}
+	}
+	i.dir = dirSOI
+	return i.next()
+}
+
+func (i *mergedIterator) next() bool {
+	var key []byte
+	if i.dir == dirForward {
+		key = i.keys[i.index]
+	}
+	for x, tkey := range i.keys {
+		if tkey != nil && (key == nil || i.cmp.Compare(tkey, key) < 0) {
+			key = tkey
+			i.index = x
+		}
+	}
+	if key == nil {
+		i.dir = dirEOI
+		return false
+	}
+	i.dir = dirForward
+	return true
+}
+
+func (i *mergedIterator) Next() bool {
+	if i.dir == dirEOI || i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	switch i.dir {
+	case dirSOI:
+		return i.First()
+	case dirBackward:
+		key := append([]byte{}, i.keys[i.index]...)
+		if !i.Seek(key) {
+			return false
+		}
+		return i.Next()
+	}
+
+	x := i.index
+	iter := i.iters[x]
+	switch {
+	case iter.Next():
+		i.keys[x] = assertKey(iter.Key())
+	case i.iterErr(iter):
+		return false
+	default:
+		i.keys[x] = nil
+	}
+	return i.next()
+}
+
+func (i *mergedIterator) prev() bool {
+	var key []byte
+	if i.dir == dirBackward {
+		key = i.keys[i.index]
+	}
+	for x, tkey := range i.keys {
+		if tkey != nil && (key == nil || i.cmp.Compare(tkey, key) > 0) {
+			key = tkey
+			i.index = x
+		}
+	}
+	if key == nil {
+		i.dir = dirSOI
+		return false
+	}
+	i.dir = dirBackward
+	return true
+}
+
+func (i *mergedIterator) Prev() bool {
+	if i.dir == dirSOI || i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	switch i.dir {
+	case dirEOI:
+		return i.Last()
+	case dirForward:
+		key := append([]byte{}, i.keys[i.index]...)
+		for x, iter := range i.iters {
+			if x == i.index {
+				continue
+			}
+			seek := iter.Seek(key)
+			switch {
+			case seek && iter.Prev(), !seek && iter.Last():
+				i.keys[x] = assertKey(iter.Key())
+			case i.iterErr(iter):
+				return false
+			default:
+				i.keys[x] = nil
+			}
+		}
+	}
+
+	x := i.index
+	iter := i.iters[x]
+	switch {
+	case iter.Prev():
+		i.keys[x] = assertKey(iter.Key())
+	case i.iterErr(iter):
+		return false
+	default:
+		i.keys[x] = nil
+	}
+	return i.prev()
+}
+
+func (i *mergedIterator) Key() []byte {
+	if i.err != nil || i.dir <= dirEOI {
+		return nil
+	}
+	return i.keys[i.index]
+}
+
+func (i *mergedIterator) Value() []byte {
+	if i.err != nil || i.dir <= dirEOI {
+		return nil
+	}
+	return i.iters[i.index].Value()
+}
+
+func (i *mergedIterator) Release() {
+	if i.dir != dirReleased {
+		i.dir = dirReleased
+		for _, iter := range i.iters {
+			iter.Release()
+		}
+		i.iters = nil
+		i.keys = nil
+		if i.releaser != nil {
+			i.releaser.Release()
+			i.releaser = nil
+		}
+	}
+}
+
+func (i *mergedIterator) SetReleaser(releaser util.Releaser) {
+	if i.dir == dirReleased {
+		panic(util.ErrReleased)
+	}
+	if i.releaser != nil && releaser != nil {
+		panic(util.ErrHasReleaser)
+	}
+	i.releaser = releaser
+}
+
+func (i *mergedIterator) Error() error {
+	return i.err
+}
+
+func (i *mergedIterator) SetErrorCallback(f func(err error)) {
+	i.errf = f
+}
+
+// NewMergedIterator returns an iterator that merges its input. Walking the
+// resultant iterator will return all key/value pairs of all input iterators
+// in strictly increasing key order, as defined by cmp.
+// The input's key ranges may overlap, but there are assumed to be no duplicate
+// keys: if iters[i] contains a key k then iters[j] will not contain that key k.
+// None of the iters may be nil.
+//
+// If strict is true the any 'corruption errors' (i.e errors.IsCorrupted(err) == true)
+// won't be ignored and will halt 'merged iterator', otherwise the iterator will
+// continue to the next 'input iterator'.
+func NewMergedIterator(iters []Iterator, cmp comparer.Comparer, strict bool) Iterator {
+	return &mergedIterator{
+		iters:  iters,
+		cmp:    cmp,
+		strict: strict,
+		keys:   make([][]byte, len(iters)),
+	}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/journal/journal.go b/vendor/github.com/syndtr/goleveldb/leveldb/journal/journal.go
new file mode 100644
index 0000000000..d094c3d0f8
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/journal/journal.go
@@ -0,0 +1,524 @@
+// Copyright 2011 The LevelDB-Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Taken from: https://code.google.com/p/leveldb-go/source/browse/leveldb/record/record.go?r=1d5ccbe03246da926391ee12d1c6caae054ff4b0
+// License, authors and contributors informations can be found at bellow URLs respectively:
+// 	https://code.google.com/p/leveldb-go/source/browse/LICENSE
+//	https://code.google.com/p/leveldb-go/source/browse/AUTHORS
+//  https://code.google.com/p/leveldb-go/source/browse/CONTRIBUTORS
+
+// Package journal reads and writes sequences of journals. Each journal is a stream
+// of bytes that completes before the next journal starts.
+//
+// When reading, call Next to obtain an io.Reader for the next journal. Next will
+// return io.EOF when there are no more journals. It is valid to call Next
+// without reading the current journal to exhaustion.
+//
+// When writing, call Next to obtain an io.Writer for the next journal. Calling
+// Next finishes the current journal. Call Close to finish the final journal.
+//
+// Optionally, call Flush to finish the current journal and flush the underlying
+// writer without starting a new journal. To start a new journal after flushing,
+// call Next.
+//
+// Neither Readers or Writers are safe to use concurrently.
+//
+// Example code:
+//	func read(r io.Reader) ([]string, error) {
+//		var ss []string
+//		journals := journal.NewReader(r, nil, true, true)
+//		for {
+//			j, err := journals.Next()
+//			if err == io.EOF {
+//				break
+//			}
+//			if err != nil {
+//				return nil, err
+//			}
+//			s, err := ioutil.ReadAll(j)
+//			if err != nil {
+//				return nil, err
+//			}
+//			ss = append(ss, string(s))
+//		}
+//		return ss, nil
+//	}
+//
+//	func write(w io.Writer, ss []string) error {
+//		journals := journal.NewWriter(w)
+//		for _, s := range ss {
+//			j, err := journals.Next()
+//			if err != nil {
+//				return err
+//			}
+//			if _, err := j.Write([]byte(s)), err != nil {
+//				return err
+//			}
+//		}
+//		return journals.Close()
+//	}
+//
+// The wire format is that the stream is divided into 32KiB blocks, and each
+// block contains a number of tightly packed chunks. Chunks cannot cross block
+// boundaries. The last block may be shorter than 32 KiB. Any unused bytes in a
+// block must be zero.
+//
+// A journal maps to one or more chunks. Each chunk has a 7 byte header (a 4
+// byte checksum, a 2 byte little-endian uint16 length, and a 1 byte chunk type)
+// followed by a payload. The checksum is over the chunk type and the payload.
+//
+// There are four chunk types: whether the chunk is the full journal, or the
+// first, middle or last chunk of a multi-chunk journal. A multi-chunk journal
+// has one first chunk, zero or more middle chunks, and one last chunk.
+//
+// The wire format allows for limited recovery in the face of data corruption:
+// on a format error (such as a checksum mismatch), the reader moves to the
+// next block and looks for the next full or first chunk.
+package journal
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// These constants are part of the wire format and should not be changed.
+const (
+	fullChunkType   = 1
+	firstChunkType  = 2
+	middleChunkType = 3
+	lastChunkType   = 4
+)
+
+const (
+	blockSize  = 32 * 1024
+	headerSize = 7
+)
+
+type flusher interface {
+	Flush() error
+}
+
+// ErrCorrupted is the error type that generated by corrupted block or chunk.
+type ErrCorrupted struct {
+	Size   int
+	Reason string
+}
+
+func (e *ErrCorrupted) Error() string {
+	return fmt.Sprintf("leveldb/journal: block/chunk corrupted: %s (%d bytes)", e.Reason, e.Size)
+}
+
+// Dropper is the interface that wrap simple Drop method. The Drop
+// method will be called when the journal reader dropping a block or chunk.
+type Dropper interface {
+	Drop(err error)
+}
+
+// Reader reads journals from an underlying io.Reader.
+type Reader struct {
+	// r is the underlying reader.
+	r io.Reader
+	// the dropper.
+	dropper Dropper
+	// strict flag.
+	strict bool
+	// checksum flag.
+	checksum bool
+	// seq is the sequence number of the current journal.
+	seq int
+	// buf[i:j] is the unread portion of the current chunk's payload.
+	// The low bound, i, excludes the chunk header.
+	i, j int
+	// n is the number of bytes of buf that are valid. Once reading has started,
+	// only the final block can have n < blockSize.
+	n int
+	// last is whether the current chunk is the last chunk of the journal.
+	last bool
+	// err is any accumulated error.
+	err error
+	// buf is the buffer.
+	buf [blockSize]byte
+}
+
+// NewReader returns a new reader. The dropper may be nil, and if
+// strict is true then corrupted or invalid chunk will halt the journal
+// reader entirely.
+func NewReader(r io.Reader, dropper Dropper, strict, checksum bool) *Reader {
+	return &Reader{
+		r:        r,
+		dropper:  dropper,
+		strict:   strict,
+		checksum: checksum,
+		last:     true,
+	}
+}
+
+var errSkip = errors.New("leveldb/journal: skipped")
+
+func (r *Reader) corrupt(n int, reason string, skip bool) error {
+	if r.dropper != nil {
+		r.dropper.Drop(&ErrCorrupted{n, reason})
+	}
+	if r.strict && !skip {
+		r.err = errors.NewErrCorrupted(storage.FileDesc{}, &ErrCorrupted{n, reason})
+		return r.err
+	}
+	return errSkip
+}
+
+// nextChunk sets r.buf[r.i:r.j] to hold the next chunk's payload, reading the
+// next block into the buffer if necessary.
+func (r *Reader) nextChunk(first bool) error {
+	for {
+		if r.j+headerSize <= r.n {
+			checksum := binary.LittleEndian.Uint32(r.buf[r.j+0 : r.j+4])
+			length := binary.LittleEndian.Uint16(r.buf[r.j+4 : r.j+6])
+			chunkType := r.buf[r.j+6]
+			unprocBlock := r.n - r.j
+			if checksum == 0 && length == 0 && chunkType == 0 {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, "zero header", false)
+			}
+			if chunkType < fullChunkType || chunkType > lastChunkType {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, fmt.Sprintf("invalid chunk type %#x", chunkType), false)
+			}
+			r.i = r.j + headerSize
+			r.j = r.j + headerSize + int(length)
+			if r.j > r.n {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, "chunk length overflows block", false)
+			} else if r.checksum && checksum != util.NewCRC(r.buf[r.i-1:r.j]).Value() {
+				// Drop entire block.
+				r.i = r.n
+				r.j = r.n
+				return r.corrupt(unprocBlock, "checksum mismatch", false)
+			}
+			if first && chunkType != fullChunkType && chunkType != firstChunkType {
+				chunkLength := (r.j - r.i) + headerSize
+				r.i = r.j
+				// Report the error, but skip it.
+				return r.corrupt(chunkLength, "orphan chunk", true)
+			}
+			r.last = chunkType == fullChunkType || chunkType == lastChunkType
+			return nil
+		}
+
+		// The last block.
+		if r.n < blockSize && r.n > 0 {
+			if !first {
+				return r.corrupt(0, "missing chunk part", false)
+			}
+			r.err = io.EOF
+			return r.err
+		}
+
+		// Read block.
+		n, err := io.ReadFull(r.r, r.buf[:])
+		if err != nil && err != io.EOF && err != io.ErrUnexpectedEOF {
+			return err
+		}
+		if n == 0 {
+			if !first {
+				return r.corrupt(0, "missing chunk part", false)
+			}
+			r.err = io.EOF
+			return r.err
+		}
+		r.i, r.j, r.n = 0, 0, n
+	}
+}
+
+// Next returns a reader for the next journal. It returns io.EOF if there are no
+// more journals. The reader returned becomes stale after the next Next call,
+// and should no longer be used. If strict is false, the reader will returns
+// io.ErrUnexpectedEOF error when found corrupted journal.
+func (r *Reader) Next() (io.Reader, error) {
+	r.seq++
+	if r.err != nil {
+		return nil, r.err
+	}
+	r.i = r.j
+	for {
+		if err := r.nextChunk(true); err == nil {
+			break
+		} else if err != errSkip {
+			return nil, err
+		}
+	}
+	return &singleReader{r, r.seq, nil}, nil
+}
+
+// Reset resets the journal reader, allows reuse of the journal reader. Reset returns
+// last accumulated error.
+func (r *Reader) Reset(reader io.Reader, dropper Dropper, strict, checksum bool) error {
+	r.seq++
+	err := r.err
+	r.r = reader
+	r.dropper = dropper
+	r.strict = strict
+	r.checksum = checksum
+	r.i = 0
+	r.j = 0
+	r.n = 0
+	r.last = true
+	r.err = nil
+	return err
+}
+
+type singleReader struct {
+	r   *Reader
+	seq int
+	err error
+}
+
+func (x *singleReader) Read(p []byte) (int, error) {
+	r := x.r
+	if r.seq != x.seq {
+		return 0, errors.New("leveldb/journal: stale reader")
+	}
+	if x.err != nil {
+		return 0, x.err
+	}
+	if r.err != nil {
+		return 0, r.err
+	}
+	for r.i == r.j {
+		if r.last {
+			return 0, io.EOF
+		}
+		x.err = r.nextChunk(false)
+		if x.err != nil {
+			if x.err == errSkip {
+				x.err = io.ErrUnexpectedEOF
+			}
+			return 0, x.err
+		}
+	}
+	n := copy(p, r.buf[r.i:r.j])
+	r.i += n
+	return n, nil
+}
+
+func (x *singleReader) ReadByte() (byte, error) {
+	r := x.r
+	if r.seq != x.seq {
+		return 0, errors.New("leveldb/journal: stale reader")
+	}
+	if x.err != nil {
+		return 0, x.err
+	}
+	if r.err != nil {
+		return 0, r.err
+	}
+	for r.i == r.j {
+		if r.last {
+			return 0, io.EOF
+		}
+		x.err = r.nextChunk(false)
+		if x.err != nil {
+			if x.err == errSkip {
+				x.err = io.ErrUnexpectedEOF
+			}
+			return 0, x.err
+		}
+	}
+	c := r.buf[r.i]
+	r.i++
+	return c, nil
+}
+
+// Writer writes journals to an underlying io.Writer.
+type Writer struct {
+	// w is the underlying writer.
+	w io.Writer
+	// seq is the sequence number of the current journal.
+	seq int
+	// f is w as a flusher.
+	f flusher
+	// buf[i:j] is the bytes that will become the current chunk.
+	// The low bound, i, includes the chunk header.
+	i, j int
+	// buf[:written] has already been written to w.
+	// written is zero unless Flush has been called.
+	written int
+	// first is whether the current chunk is the first chunk of the journal.
+	first bool
+	// pending is whether a chunk is buffered but not yet written.
+	pending bool
+	// err is any accumulated error.
+	err error
+	// buf is the buffer.
+	buf [blockSize]byte
+}
+
+// NewWriter returns a new Writer.
+func NewWriter(w io.Writer) *Writer {
+	f, _ := w.(flusher)
+	return &Writer{
+		w: w,
+		f: f,
+	}
+}
+
+// fillHeader fills in the header for the pending chunk.
+func (w *Writer) fillHeader(last bool) {
+	if w.i+headerSize > w.j || w.j > blockSize {
+		panic("leveldb/journal: bad writer state")
+	}
+	if last {
+		if w.first {
+			w.buf[w.i+6] = fullChunkType
+		} else {
+			w.buf[w.i+6] = lastChunkType
+		}
+	} else {
+		if w.first {
+			w.buf[w.i+6] = firstChunkType
+		} else {
+			w.buf[w.i+6] = middleChunkType
+		}
+	}
+	binary.LittleEndian.PutUint32(w.buf[w.i+0:w.i+4], util.NewCRC(w.buf[w.i+6:w.j]).Value())
+	binary.LittleEndian.PutUint16(w.buf[w.i+4:w.i+6], uint16(w.j-w.i-headerSize))
+}
+
+// writeBlock writes the buffered block to the underlying writer, and reserves
+// space for the next chunk's header.
+func (w *Writer) writeBlock() {
+	_, w.err = w.w.Write(w.buf[w.written:])
+	w.i = 0
+	w.j = headerSize
+	w.written = 0
+}
+
+// writePending finishes the current journal and writes the buffer to the
+// underlying writer.
+func (w *Writer) writePending() {
+	if w.err != nil {
+		return
+	}
+	if w.pending {
+		w.fillHeader(true)
+		w.pending = false
+	}
+	_, w.err = w.w.Write(w.buf[w.written:w.j])
+	w.written = w.j
+}
+
+// Close finishes the current journal and closes the writer.
+func (w *Writer) Close() error {
+	w.seq++
+	w.writePending()
+	if w.err != nil {
+		return w.err
+	}
+	w.err = errors.New("leveldb/journal: closed Writer")
+	return nil
+}
+
+// Flush finishes the current journal, writes to the underlying writer, and
+// flushes it if that writer implements interface{ Flush() error }.
+func (w *Writer) Flush() error {
+	w.seq++
+	w.writePending()
+	if w.err != nil {
+		return w.err
+	}
+	if w.f != nil {
+		w.err = w.f.Flush()
+		return w.err
+	}
+	return nil
+}
+
+// Reset resets the journal writer, allows reuse of the journal writer. Reset
+// will also closes the journal writer if not already.
+func (w *Writer) Reset(writer io.Writer) (err error) {
+	w.seq++
+	if w.err == nil {
+		w.writePending()
+		err = w.err
+	}
+	w.w = writer
+	w.f, _ = writer.(flusher)
+	w.i = 0
+	w.j = 0
+	w.written = 0
+	w.first = false
+	w.pending = false
+	w.err = nil
+	return
+}
+
+// Next returns a writer for the next journal. The writer returned becomes stale
+// after the next Close, Flush or Next call, and should no longer be used.
+func (w *Writer) Next() (io.Writer, error) {
+	w.seq++
+	if w.err != nil {
+		return nil, w.err
+	}
+	if w.pending {
+		w.fillHeader(true)
+	}
+	w.i = w.j
+	w.j = w.j + headerSize
+	// Check if there is room in the block for the header.
+	if w.j > blockSize {
+		// Fill in the rest of the block with zeroes.
+		for k := w.i; k < blockSize; k++ {
+			w.buf[k] = 0
+		}
+		w.writeBlock()
+		if w.err != nil {
+			return nil, w.err
+		}
+	}
+	w.first = true
+	w.pending = true
+	return singleWriter{w, w.seq}, nil
+}
+
+type singleWriter struct {
+	w   *Writer
+	seq int
+}
+
+func (x singleWriter) Write(p []byte) (int, error) {
+	w := x.w
+	if w.seq != x.seq {
+		return 0, errors.New("leveldb/journal: stale writer")
+	}
+	if w.err != nil {
+		return 0, w.err
+	}
+	n0 := len(p)
+	for len(p) > 0 {
+		// Write a block, if it is full.
+		if w.j == blockSize {
+			w.fillHeader(false)
+			w.writeBlock()
+			if w.err != nil {
+				return 0, w.err
+			}
+			w.first = false
+		}
+		// Copy bytes into the buffer.
+		n := copy(w.buf[w.j:], p)
+		w.j += n
+		p = p[n:]
+	}
+	return n0, nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/key.go b/vendor/github.com/syndtr/goleveldb/leveldb/key.go
new file mode 100644
index 0000000000..ad8f51ec85
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/key.go
@@ -0,0 +1,143 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+// ErrInternalKeyCorrupted records internal key corruption.
+type ErrInternalKeyCorrupted struct {
+	Ikey   []byte
+	Reason string
+}
+
+func (e *ErrInternalKeyCorrupted) Error() string {
+	return fmt.Sprintf("leveldb: internal key %q corrupted: %s", e.Ikey, e.Reason)
+}
+
+func newErrInternalKeyCorrupted(ikey []byte, reason string) error {
+	return errors.NewErrCorrupted(storage.FileDesc{}, &ErrInternalKeyCorrupted{append([]byte{}, ikey...), reason})
+}
+
+type keyType uint
+
+func (kt keyType) String() string {
+	switch kt {
+	case keyTypeDel:
+		return "d"
+	case keyTypeVal:
+		return "v"
+	}
+	return fmt.Sprintf("<invalid:%#x>", uint(kt))
+}
+
+// Value types encoded as the last component of internal keys.
+// Don't modify; this value are saved to disk.
+const (
+	keyTypeDel = keyType(0)
+	keyTypeVal = keyType(1)
+)
+
+// keyTypeSeek defines the keyType that should be passed when constructing an
+// internal key for seeking to a particular sequence number (since we
+// sort sequence numbers in decreasing order and the value type is
+// embedded as the low 8 bits in the sequence number in internal keys,
+// we need to use the highest-numbered ValueType, not the lowest).
+const keyTypeSeek = keyTypeVal
+
+const (
+	// Maximum value possible for sequence number; the 8-bits are
+	// used by value type, so its can packed together in single
+	// 64-bit integer.
+	keyMaxSeq = (uint64(1) << 56) - 1
+	// Maximum value possible for packed sequence number and type.
+	keyMaxNum = (keyMaxSeq << 8) | uint64(keyTypeSeek)
+)
+
+// Maximum number encoded in bytes.
+var keyMaxNumBytes = make([]byte, 8)
+
+func init() {
+	binary.LittleEndian.PutUint64(keyMaxNumBytes, keyMaxNum)
+}
+
+type internalKey []byte
+
+func makeInternalKey(dst, ukey []byte, seq uint64, kt keyType) internalKey {
+	if seq > keyMaxSeq {
+		panic("leveldb: invalid sequence number")
+	} else if kt > keyTypeVal {
+		panic("leveldb: invalid type")
+	}
+
+	dst = ensureBuffer(dst, len(ukey)+8)
+	copy(dst, ukey)
+	binary.LittleEndian.PutUint64(dst[len(ukey):], (seq<<8)|uint64(kt))
+	return internalKey(dst)
+}
+
+func parseInternalKey(ik []byte) (ukey []byte, seq uint64, kt keyType, err error) {
+	if len(ik) < 8 {
+		return nil, 0, 0, newErrInternalKeyCorrupted(ik, "invalid length")
+	}
+	num := binary.LittleEndian.Uint64(ik[len(ik)-8:])
+	seq, kt = uint64(num>>8), keyType(num&0xff)
+	if kt > keyTypeVal {
+		return nil, 0, 0, newErrInternalKeyCorrupted(ik, "invalid type")
+	}
+	ukey = ik[:len(ik)-8]
+	return
+}
+
+func validInternalKey(ik []byte) bool {
+	_, _, _, err := parseInternalKey(ik)
+	return err == nil
+}
+
+func (ik internalKey) assert() {
+	if ik == nil {
+		panic("leveldb: nil internalKey")
+	}
+	if len(ik) < 8 {
+		panic(fmt.Sprintf("leveldb: internal key %q, len=%d: invalid length", []byte(ik), len(ik)))
+	}
+}
+
+func (ik internalKey) ukey() []byte {
+	ik.assert()
+	return ik[:len(ik)-8]
+}
+
+func (ik internalKey) num() uint64 {
+	ik.assert()
+	return binary.LittleEndian.Uint64(ik[len(ik)-8:])
+}
+
+func (ik internalKey) parseNum() (seq uint64, kt keyType) {
+	num := ik.num()
+	seq, kt = uint64(num>>8), keyType(num&0xff)
+	if kt > keyTypeVal {
+		panic(fmt.Sprintf("leveldb: internal key %q, len=%d: invalid type %#x", []byte(ik), len(ik), kt))
+	}
+	return
+}
+
+func (ik internalKey) String() string {
+	if ik == nil {
+		return "<nil>"
+	}
+
+	if ukey, seq, kt, err := parseInternalKey(ik); err == nil {
+		return fmt.Sprintf("%s,%s%d", shorten(string(ukey)), kt, seq)
+	}
+	return fmt.Sprintf("<invalid:%#x>", []byte(ik))
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/memdb/memdb.go b/vendor/github.com/syndtr/goleveldb/leveldb/memdb/memdb.go
new file mode 100644
index 0000000000..b661c08a93
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/memdb/memdb.go
@@ -0,0 +1,475 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package memdb provides in-memory key/value database implementation.
+package memdb
+
+import (
+	"math/rand"
+	"sync"
+
+	"github.com/syndtr/goleveldb/leveldb/comparer"
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// Common errors.
+var (
+	ErrNotFound     = errors.ErrNotFound
+	ErrIterReleased = errors.New("leveldb/memdb: iterator released")
+)
+
+const tMaxHeight = 12
+
+type dbIter struct {
+	util.BasicReleaser
+	p          *DB
+	slice      *util.Range
+	node       int
+	forward    bool
+	key, value []byte
+	err        error
+}
+
+func (i *dbIter) fill(checkStart, checkLimit bool) bool {
+	if i.node != 0 {
+		n := i.p.nodeData[i.node]
+		m := n + i.p.nodeData[i.node+nKey]
+		i.key = i.p.kvData[n:m]
+		if i.slice != nil {
+			switch {
+			case checkLimit && i.slice.Limit != nil && i.p.cmp.Compare(i.key, i.slice.Limit) >= 0:
+				fallthrough
+			case checkStart && i.slice.Start != nil && i.p.cmp.Compare(i.key, i.slice.Start) < 0:
+				i.node = 0
+				goto bail
+			}
+		}
+		i.value = i.p.kvData[m : m+i.p.nodeData[i.node+nVal]]
+		return true
+	}
+bail:
+	i.key = nil
+	i.value = nil
+	return false
+}
+
+func (i *dbIter) Valid() bool {
+	return i.node != 0
+}
+
+func (i *dbIter) First() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	i.forward = true
+	i.p.mu.RLock()
+	defer i.p.mu.RUnlock()
+	if i.slice != nil && i.slice.Start != nil {
+		i.node, _ = i.p.findGE(i.slice.Start, false)
+	} else {
+		i.node = i.p.nodeData[nNext]
+	}
+	return i.fill(false, true)
+}
+
+func (i *dbIter) Last() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	i.forward = false
+	i.p.mu.RLock()
+	defer i.p.mu.RUnlock()
+	if i.slice != nil && i.slice.Limit != nil {
+		i.node = i.p.findLT(i.slice.Limit)
+	} else {
+		i.node = i.p.findLast()
+	}
+	return i.fill(true, false)
+}
+
+func (i *dbIter) Seek(key []byte) bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	i.forward = true
+	i.p.mu.RLock()
+	defer i.p.mu.RUnlock()
+	if i.slice != nil && i.slice.Start != nil && i.p.cmp.Compare(key, i.slice.Start) < 0 {
+		key = i.slice.Start
+	}
+	i.node, _ = i.p.findGE(key, false)
+	return i.fill(false, true)
+}
+
+func (i *dbIter) Next() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.node == 0 {
+		if !i.forward {
+			return i.First()
+		}
+		return false
+	}
+	i.forward = true
+	i.p.mu.RLock()
+	defer i.p.mu.RUnlock()
+	i.node = i.p.nodeData[i.node+nNext]
+	return i.fill(false, true)
+}
+
+func (i *dbIter) Prev() bool {
+	if i.Released() {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.node == 0 {
+		if i.forward {
+			return i.Last()
+		}
+		return false
+	}
+	i.forward = false
+	i.p.mu.RLock()
+	defer i.p.mu.RUnlock()
+	i.node = i.p.findLT(i.key)
+	return i.fill(true, false)
+}
+
+func (i *dbIter) Key() []byte {
+	return i.key
+}
+
+func (i *dbIter) Value() []byte {
+	return i.value
+}
+
+func (i *dbIter) Error() error { return i.err }
+
+func (i *dbIter) Release() {
+	if !i.Released() {
+		i.p = nil
+		i.node = 0
+		i.key = nil
+		i.value = nil
+		i.BasicReleaser.Release()
+	}
+}
+
+const (
+	nKV = iota
+	nKey
+	nVal
+	nHeight
+	nNext
+)
+
+// DB is an in-memory key/value database.
+type DB struct {
+	cmp comparer.BasicComparer
+	rnd *rand.Rand
+
+	mu     sync.RWMutex
+	kvData []byte
+	// Node data:
+	// [0]         : KV offset
+	// [1]         : Key length
+	// [2]         : Value length
+	// [3]         : Height
+	// [3..height] : Next nodes
+	nodeData  []int
+	prevNode  [tMaxHeight]int
+	maxHeight int
+	n         int
+	kvSize    int
+}
+
+func (p *DB) randHeight() (h int) {
+	const branching = 4
+	h = 1
+	for h < tMaxHeight && p.rnd.Int()%branching == 0 {
+		h++
+	}
+	return
+}
+
+// Must hold RW-lock if prev == true, as it use shared prevNode slice.
+func (p *DB) findGE(key []byte, prev bool) (int, bool) {
+	node := 0
+	h := p.maxHeight - 1
+	for {
+		next := p.nodeData[node+nNext+h]
+		cmp := 1
+		if next != 0 {
+			o := p.nodeData[next]
+			cmp = p.cmp.Compare(p.kvData[o:o+p.nodeData[next+nKey]], key)
+		}
+		if cmp < 0 {
+			// Keep searching in this list
+			node = next
+		} else {
+			if prev {
+				p.prevNode[h] = node
+			} else if cmp == 0 {
+				return next, true
+			}
+			if h == 0 {
+				return next, cmp == 0
+			}
+			h--
+		}
+	}
+}
+
+func (p *DB) findLT(key []byte) int {
+	node := 0
+	h := p.maxHeight - 1
+	for {
+		next := p.nodeData[node+nNext+h]
+		o := p.nodeData[next]
+		if next == 0 || p.cmp.Compare(p.kvData[o:o+p.nodeData[next+nKey]], key) >= 0 {
+			if h == 0 {
+				break
+			}
+			h--
+		} else {
+			node = next
+		}
+	}
+	return node
+}
+
+func (p *DB) findLast() int {
+	node := 0
+	h := p.maxHeight - 1
+	for {
+		next := p.nodeData[node+nNext+h]
+		if next == 0 {
+			if h == 0 {
+				break
+			}
+			h--
+		} else {
+			node = next
+		}
+	}
+	return node
+}
+
+// Put sets the value for the given key. It overwrites any previous value
+// for that key; a DB is not a multi-map.
+//
+// It is safe to modify the contents of the arguments after Put returns.
+func (p *DB) Put(key []byte, value []byte) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	if node, exact := p.findGE(key, true); exact {
+		kvOffset := len(p.kvData)
+		p.kvData = append(p.kvData, key...)
+		p.kvData = append(p.kvData, value...)
+		p.nodeData[node] = kvOffset
+		m := p.nodeData[node+nVal]
+		p.nodeData[node+nVal] = len(value)
+		p.kvSize += len(value) - m
+		return nil
+	}
+
+	h := p.randHeight()
+	if h > p.maxHeight {
+		for i := p.maxHeight; i < h; i++ {
+			p.prevNode[i] = 0
+		}
+		p.maxHeight = h
+	}
+
+	kvOffset := len(p.kvData)
+	p.kvData = append(p.kvData, key...)
+	p.kvData = append(p.kvData, value...)
+	// Node
+	node := len(p.nodeData)
+	p.nodeData = append(p.nodeData, kvOffset, len(key), len(value), h)
+	for i, n := range p.prevNode[:h] {
+		m := n + nNext + i
+		p.nodeData = append(p.nodeData, p.nodeData[m])
+		p.nodeData[m] = node
+	}
+
+	p.kvSize += len(key) + len(value)
+	p.n++
+	return nil
+}
+
+// Delete deletes the value for the given key. It returns ErrNotFound if
+// the DB does not contain the key.
+//
+// It is safe to modify the contents of the arguments after Delete returns.
+func (p *DB) Delete(key []byte) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+
+	node, exact := p.findGE(key, true)
+	if !exact {
+		return ErrNotFound
+	}
+
+	h := p.nodeData[node+nHeight]
+	for i, n := range p.prevNode[:h] {
+		m := n + nNext + i
+		p.nodeData[m] = p.nodeData[p.nodeData[m]+nNext+i]
+	}
+
+	p.kvSize -= p.nodeData[node+nKey] + p.nodeData[node+nVal]
+	p.n--
+	return nil
+}
+
+// Contains returns true if the given key are in the DB.
+//
+// It is safe to modify the contents of the arguments after Contains returns.
+func (p *DB) Contains(key []byte) bool {
+	p.mu.RLock()
+	_, exact := p.findGE(key, false)
+	p.mu.RUnlock()
+	return exact
+}
+
+// Get gets the value for the given key. It returns error.ErrNotFound if the
+// DB does not contain the key.
+//
+// The caller should not modify the contents of the returned slice, but
+// it is safe to modify the contents of the argument after Get returns.
+func (p *DB) Get(key []byte) (value []byte, err error) {
+	p.mu.RLock()
+	if node, exact := p.findGE(key, false); exact {
+		o := p.nodeData[node] + p.nodeData[node+nKey]
+		value = p.kvData[o : o+p.nodeData[node+nVal]]
+	} else {
+		err = ErrNotFound
+	}
+	p.mu.RUnlock()
+	return
+}
+
+// Find finds key/value pair whose key is greater than or equal to the
+// given key. It returns ErrNotFound if the table doesn't contain
+// such pair.
+//
+// The caller should not modify the contents of the returned slice, but
+// it is safe to modify the contents of the argument after Find returns.
+func (p *DB) Find(key []byte) (rkey, value []byte, err error) {
+	p.mu.RLock()
+	if node, _ := p.findGE(key, false); node != 0 {
+		n := p.nodeData[node]
+		m := n + p.nodeData[node+nKey]
+		rkey = p.kvData[n:m]
+		value = p.kvData[m : m+p.nodeData[node+nVal]]
+	} else {
+		err = ErrNotFound
+	}
+	p.mu.RUnlock()
+	return
+}
+
+// NewIterator returns an iterator of the DB.
+// The returned iterator is not safe for concurrent use, but it is safe to use
+// multiple iterators concurrently, with each in a dedicated goroutine.
+// It is also safe to use an iterator concurrently with modifying its
+// underlying DB. However, the resultant key/value pairs are not guaranteed
+// to be a consistent snapshot of the DB at a particular point in time.
+//
+// Slice allows slicing the iterator to only contains keys in the given
+// range. A nil Range.Start is treated as a key before all keys in the
+// DB. And a nil Range.Limit is treated as a key after all keys in
+// the DB.
+//
+// The iterator must be released after use, by calling Release method.
+//
+// Also read Iterator documentation of the leveldb/iterator package.
+func (p *DB) NewIterator(slice *util.Range) iterator.Iterator {
+	return &dbIter{p: p, slice: slice}
+}
+
+// Capacity returns keys/values buffer capacity.
+func (p *DB) Capacity() int {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return cap(p.kvData)
+}
+
+// Size returns sum of keys and values length. Note that deleted
+// key/value will not be accounted for, but it will still consume
+// the buffer, since the buffer is append only.
+func (p *DB) Size() int {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return p.kvSize
+}
+
+// Free returns keys/values free buffer before need to grow.
+func (p *DB) Free() int {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return cap(p.kvData) - len(p.kvData)
+}
+
+// Len returns the number of entries in the DB.
+func (p *DB) Len() int {
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+	return p.n
+}
+
+// Reset resets the DB to initial empty state. Allows reuse the buffer.
+func (p *DB) Reset() {
+	p.mu.Lock()
+	p.rnd = rand.New(rand.NewSource(0xdeadbeef))
+	p.maxHeight = 1
+	p.n = 0
+	p.kvSize = 0
+	p.kvData = p.kvData[:0]
+	p.nodeData = p.nodeData[:nNext+tMaxHeight]
+	p.nodeData[nKV] = 0
+	p.nodeData[nKey] = 0
+	p.nodeData[nVal] = 0
+	p.nodeData[nHeight] = tMaxHeight
+	for n := 0; n < tMaxHeight; n++ {
+		p.nodeData[nNext+n] = 0
+		p.prevNode[n] = 0
+	}
+	p.mu.Unlock()
+}
+
+// New creates a new initialized in-memory key/value DB. The capacity
+// is the initial key/value buffer capacity. The capacity is advisory,
+// not enforced.
+//
+// This DB is append-only, deleting an entry would remove entry node but not
+// reclaim KV buffer.
+//
+// The returned DB instance is safe for concurrent use.
+func New(cmp comparer.BasicComparer, capacity int) *DB {
+	p := &DB{
+		cmp:       cmp,
+		rnd:       rand.New(rand.NewSource(0xdeadbeef)),
+		maxHeight: 1,
+		kvData:    make([]byte, 0, capacity),
+		nodeData:  make([]int, 4+tMaxHeight),
+	}
+	p.nodeData[nHeight] = tMaxHeight
+	return p
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go b/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go
new file mode 100644
index 0000000000..528b164233
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/opt/options.go
@@ -0,0 +1,697 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package opt provides sets of options used by LevelDB.
+package opt
+
+import (
+	"math"
+
+	"github.com/syndtr/goleveldb/leveldb/cache"
+	"github.com/syndtr/goleveldb/leveldb/comparer"
+	"github.com/syndtr/goleveldb/leveldb/filter"
+)
+
+const (
+	KiB = 1024
+	MiB = KiB * 1024
+	GiB = MiB * 1024
+)
+
+var (
+	DefaultBlockCacher                   = LRUCacher
+	DefaultBlockCacheCapacity            = 8 * MiB
+	DefaultBlockRestartInterval          = 16
+	DefaultBlockSize                     = 4 * KiB
+	DefaultCompactionExpandLimitFactor   = 25
+	DefaultCompactionGPOverlapsFactor    = 10
+	DefaultCompactionL0Trigger           = 4
+	DefaultCompactionSourceLimitFactor   = 1
+	DefaultCompactionTableSize           = 2 * MiB
+	DefaultCompactionTableSizeMultiplier = 1.0
+	DefaultCompactionTotalSize           = 10 * MiB
+	DefaultCompactionTotalSizeMultiplier = 10.0
+	DefaultCompressionType               = SnappyCompression
+	DefaultIteratorSamplingRate          = 1 * MiB
+	DefaultOpenFilesCacher               = LRUCacher
+	DefaultOpenFilesCacheCapacity        = 500
+	DefaultWriteBuffer                   = 4 * MiB
+	DefaultWriteL0PauseTrigger           = 12
+	DefaultWriteL0SlowdownTrigger        = 8
+)
+
+// Cacher is a caching algorithm.
+type Cacher interface {
+	New(capacity int) cache.Cacher
+}
+
+type CacherFunc struct {
+	NewFunc func(capacity int) cache.Cacher
+}
+
+func (f *CacherFunc) New(capacity int) cache.Cacher {
+	if f.NewFunc != nil {
+		return f.NewFunc(capacity)
+	}
+	return nil
+}
+
+func noCacher(int) cache.Cacher { return nil }
+
+var (
+	// LRUCacher is the LRU-cache algorithm.
+	LRUCacher = &CacherFunc{cache.NewLRU}
+
+	// NoCacher is the value to disable caching algorithm.
+	NoCacher = &CacherFunc{}
+)
+
+// Compression is the 'sorted table' block compression algorithm to use.
+type Compression uint
+
+func (c Compression) String() string {
+	switch c {
+	case DefaultCompression:
+		return "default"
+	case NoCompression:
+		return "none"
+	case SnappyCompression:
+		return "snappy"
+	}
+	return "invalid"
+}
+
+const (
+	DefaultCompression Compression = iota
+	NoCompression
+	SnappyCompression
+	nCompression
+)
+
+// Strict is the DB 'strict level'.
+type Strict uint
+
+const (
+	// If present then a corrupted or invalid chunk or block in manifest
+	// journal will cause an error instead of being dropped.
+	// This will prevent database with corrupted manifest to be opened.
+	StrictManifest Strict = 1 << iota
+
+	// If present then journal chunk checksum will be verified.
+	StrictJournalChecksum
+
+	// If present then a corrupted or invalid chunk or block in journal
+	// will cause an error instead of being dropped.
+	// This will prevent database with corrupted journal to be opened.
+	StrictJournal
+
+	// If present then 'sorted table' block checksum will be verified.
+	// This has effect on both 'read operation' and compaction.
+	StrictBlockChecksum
+
+	// If present then a corrupted 'sorted table' will fails compaction.
+	// The database will enter read-only mode.
+	StrictCompaction
+
+	// If present then a corrupted 'sorted table' will halts 'read operation'.
+	StrictReader
+
+	// If present then leveldb.Recover will drop corrupted 'sorted table'.
+	StrictRecovery
+
+	// This only applicable for ReadOptions, if present then this ReadOptions
+	// 'strict level' will override global ones.
+	StrictOverride
+
+	// StrictAll enables all strict flags.
+	StrictAll = StrictManifest | StrictJournalChecksum | StrictJournal | StrictBlockChecksum | StrictCompaction | StrictReader | StrictRecovery
+
+	// DefaultStrict is the default strict flags. Specify any strict flags
+	// will override default strict flags as whole (i.e. not OR'ed).
+	DefaultStrict = StrictJournalChecksum | StrictBlockChecksum | StrictCompaction | StrictReader
+
+	// NoStrict disables all strict flags. Override default strict flags.
+	NoStrict = ^StrictAll
+)
+
+// Options holds the optional parameters for the DB at large.
+type Options struct {
+	// AltFilters defines one or more 'alternative filters'.
+	// 'alternative filters' will be used during reads if a filter block
+	// does not match with the 'effective filter'.
+	//
+	// The default value is nil
+	AltFilters []filter.Filter
+
+	// BlockCacher provides cache algorithm for LevelDB 'sorted table' block caching.
+	// Specify NoCacher to disable caching algorithm.
+	//
+	// The default value is LRUCacher.
+	BlockCacher Cacher
+
+	// BlockCacheCapacity defines the capacity of the 'sorted table' block caching.
+	// Use -1 for zero, this has same effect as specifying NoCacher to BlockCacher.
+	//
+	// The default value is 8MiB.
+	BlockCacheCapacity int
+
+	// BlockCacheEvictRemoved allows enable forced-eviction on cached block belonging
+	// to removed 'sorted table'.
+	//
+	// The default if false.
+	BlockCacheEvictRemoved bool
+
+	// BlockRestartInterval is the number of keys between restart points for
+	// delta encoding of keys.
+	//
+	// The default value is 16.
+	BlockRestartInterval int
+
+	// BlockSize is the minimum uncompressed size in bytes of each 'sorted table'
+	// block.
+	//
+	// The default value is 4KiB.
+	BlockSize int
+
+	// CompactionExpandLimitFactor limits compaction size after expanded.
+	// This will be multiplied by table size limit at compaction target level.
+	//
+	// The default value is 25.
+	CompactionExpandLimitFactor int
+
+	// CompactionGPOverlapsFactor limits overlaps in grandparent (Level + 2) that a
+	// single 'sorted table' generates.
+	// This will be multiplied by table size limit at grandparent level.
+	//
+	// The default value is 10.
+	CompactionGPOverlapsFactor int
+
+	// CompactionL0Trigger defines number of 'sorted table' at level-0 that will
+	// trigger compaction.
+	//
+	// The default value is 4.
+	CompactionL0Trigger int
+
+	// CompactionSourceLimitFactor limits compaction source size. This doesn't apply to
+	// level-0.
+	// This will be multiplied by table size limit at compaction target level.
+	//
+	// The default value is 1.
+	CompactionSourceLimitFactor int
+
+	// CompactionTableSize limits size of 'sorted table' that compaction generates.
+	// The limits for each level will be calculated as:
+	//   CompactionTableSize * (CompactionTableSizeMultiplier ^ Level)
+	// The multiplier for each level can also fine-tuned using CompactionTableSizeMultiplierPerLevel.
+	//
+	// The default value is 2MiB.
+	CompactionTableSize int
+
+	// CompactionTableSizeMultiplier defines multiplier for CompactionTableSize.
+	//
+	// The default value is 1.
+	CompactionTableSizeMultiplier float64
+
+	// CompactionTableSizeMultiplierPerLevel defines per-level multiplier for
+	// CompactionTableSize.
+	// Use zero to skip a level.
+	//
+	// The default value is nil.
+	CompactionTableSizeMultiplierPerLevel []float64
+
+	// CompactionTotalSize limits total size of 'sorted table' for each level.
+	// The limits for each level will be calculated as:
+	//   CompactionTotalSize * (CompactionTotalSizeMultiplier ^ Level)
+	// The multiplier for each level can also fine-tuned using
+	// CompactionTotalSizeMultiplierPerLevel.
+	//
+	// The default value is 10MiB.
+	CompactionTotalSize int
+
+	// CompactionTotalSizeMultiplier defines multiplier for CompactionTotalSize.
+	//
+	// The default value is 10.
+	CompactionTotalSizeMultiplier float64
+
+	// CompactionTotalSizeMultiplierPerLevel defines per-level multiplier for
+	// CompactionTotalSize.
+	// Use zero to skip a level.
+	//
+	// The default value is nil.
+	CompactionTotalSizeMultiplierPerLevel []float64
+
+	// Comparer defines a total ordering over the space of []byte keys: a 'less
+	// than' relationship. The same comparison algorithm must be used for reads
+	// and writes over the lifetime of the DB.
+	//
+	// The default value uses the same ordering as bytes.Compare.
+	Comparer comparer.Comparer
+
+	// Compression defines the 'sorted table' block compression to use.
+	//
+	// The default value (DefaultCompression) uses snappy compression.
+	Compression Compression
+
+	// DisableBufferPool allows disable use of util.BufferPool functionality.
+	//
+	// The default value is false.
+	DisableBufferPool bool
+
+	// DisableBlockCache allows disable use of cache.Cache functionality on
+	// 'sorted table' block.
+	//
+	// The default value is false.
+	DisableBlockCache bool
+
+	// DisableCompactionBackoff allows disable compaction retry backoff.
+	//
+	// The default value is false.
+	DisableCompactionBackoff bool
+
+	// DisableLargeBatchTransaction allows disabling switch-to-transaction mode
+	// on large batch write. If enable batch writes large than WriteBuffer will
+	// use transaction.
+	//
+	// The default is false.
+	DisableLargeBatchTransaction bool
+
+	// ErrorIfExist defines whether an error should returned if the DB already
+	// exist.
+	//
+	// The default value is false.
+	ErrorIfExist bool
+
+	// ErrorIfMissing defines whether an error should returned if the DB is
+	// missing. If false then the database will be created if missing, otherwise
+	// an error will be returned.
+	//
+	// The default value is false.
+	ErrorIfMissing bool
+
+	// Filter defines an 'effective filter' to use. An 'effective filter'
+	// if defined will be used to generate per-table filter block.
+	// The filter name will be stored on disk.
+	// During reads LevelDB will try to find matching filter from
+	// 'effective filter' and 'alternative filters'.
+	//
+	// Filter can be changed after a DB has been created. It is recommended
+	// to put old filter to the 'alternative filters' to mitigate lack of
+	// filter during transition period.
+	//
+	// A filter is used to reduce disk reads when looking for a specific key.
+	//
+	// The default value is nil.
+	Filter filter.Filter
+
+	// IteratorSamplingRate defines approximate gap (in bytes) between read
+	// sampling of an iterator. The samples will be used to determine when
+	// compaction should be triggered.
+	//
+	// The default is 1MiB.
+	IteratorSamplingRate int
+
+	// NoSync allows completely disable fsync.
+	//
+	// The default is false.
+	NoSync bool
+
+	// NoWriteMerge allows disabling write merge.
+	//
+	// The default is false.
+	NoWriteMerge bool
+
+	// OpenFilesCacher provides cache algorithm for open files caching.
+	// Specify NoCacher to disable caching algorithm.
+	//
+	// The default value is LRUCacher.
+	OpenFilesCacher Cacher
+
+	// OpenFilesCacheCapacity defines the capacity of the open files caching.
+	// Use -1 for zero, this has same effect as specifying NoCacher to OpenFilesCacher.
+	//
+	// The default value is 500.
+	OpenFilesCacheCapacity int
+
+	// If true then opens DB in read-only mode.
+	//
+	// The default value is false.
+	ReadOnly bool
+
+	// Strict defines the DB strict level.
+	Strict Strict
+
+	// WriteBuffer defines maximum size of a 'memdb' before flushed to
+	// 'sorted table'. 'memdb' is an in-memory DB backed by an on-disk
+	// unsorted journal.
+	//
+	// LevelDB may held up to two 'memdb' at the same time.
+	//
+	// The default value is 4MiB.
+	WriteBuffer int
+
+	// WriteL0StopTrigger defines number of 'sorted table' at level-0 that will
+	// pause write.
+	//
+	// The default value is 12.
+	WriteL0PauseTrigger int
+
+	// WriteL0SlowdownTrigger defines number of 'sorted table' at level-0 that
+	// will trigger write slowdown.
+	//
+	// The default value is 8.
+	WriteL0SlowdownTrigger int
+}
+
+func (o *Options) GetAltFilters() []filter.Filter {
+	if o == nil {
+		return nil
+	}
+	return o.AltFilters
+}
+
+func (o *Options) GetBlockCacher() Cacher {
+	if o == nil || o.BlockCacher == nil {
+		return DefaultBlockCacher
+	} else if o.BlockCacher == NoCacher {
+		return nil
+	}
+	return o.BlockCacher
+}
+
+func (o *Options) GetBlockCacheCapacity() int {
+	if o == nil || o.BlockCacheCapacity == 0 {
+		return DefaultBlockCacheCapacity
+	} else if o.BlockCacheCapacity < 0 {
+		return 0
+	}
+	return o.BlockCacheCapacity
+}
+
+func (o *Options) GetBlockCacheEvictRemoved() bool {
+	if o == nil {
+		return false
+	}
+	return o.BlockCacheEvictRemoved
+}
+
+func (o *Options) GetBlockRestartInterval() int {
+	if o == nil || o.BlockRestartInterval <= 0 {
+		return DefaultBlockRestartInterval
+	}
+	return o.BlockRestartInterval
+}
+
+func (o *Options) GetBlockSize() int {
+	if o == nil || o.BlockSize <= 0 {
+		return DefaultBlockSize
+	}
+	return o.BlockSize
+}
+
+func (o *Options) GetCompactionExpandLimit(level int) int {
+	factor := DefaultCompactionExpandLimitFactor
+	if o != nil && o.CompactionExpandLimitFactor > 0 {
+		factor = o.CompactionExpandLimitFactor
+	}
+	return o.GetCompactionTableSize(level+1) * factor
+}
+
+func (o *Options) GetCompactionGPOverlaps(level int) int {
+	factor := DefaultCompactionGPOverlapsFactor
+	if o != nil && o.CompactionGPOverlapsFactor > 0 {
+		factor = o.CompactionGPOverlapsFactor
+	}
+	return o.GetCompactionTableSize(level+2) * factor
+}
+
+func (o *Options) GetCompactionL0Trigger() int {
+	if o == nil || o.CompactionL0Trigger == 0 {
+		return DefaultCompactionL0Trigger
+	}
+	return o.CompactionL0Trigger
+}
+
+func (o *Options) GetCompactionSourceLimit(level int) int {
+	factor := DefaultCompactionSourceLimitFactor
+	if o != nil && o.CompactionSourceLimitFactor > 0 {
+		factor = o.CompactionSourceLimitFactor
+	}
+	return o.GetCompactionTableSize(level+1) * factor
+}
+
+func (o *Options) GetCompactionTableSize(level int) int {
+	var (
+		base = DefaultCompactionTableSize
+		mult float64
+	)
+	if o != nil {
+		if o.CompactionTableSize > 0 {
+			base = o.CompactionTableSize
+		}
+		if level < len(o.CompactionTableSizeMultiplierPerLevel) && o.CompactionTableSizeMultiplierPerLevel[level] > 0 {
+			mult = o.CompactionTableSizeMultiplierPerLevel[level]
+		} else if o.CompactionTableSizeMultiplier > 0 {
+			mult = math.Pow(o.CompactionTableSizeMultiplier, float64(level))
+		}
+	}
+	if mult == 0 {
+		mult = math.Pow(DefaultCompactionTableSizeMultiplier, float64(level))
+	}
+	return int(float64(base) * mult)
+}
+
+func (o *Options) GetCompactionTotalSize(level int) int64 {
+	var (
+		base = DefaultCompactionTotalSize
+		mult float64
+	)
+	if o != nil {
+		if o.CompactionTotalSize > 0 {
+			base = o.CompactionTotalSize
+		}
+		if level < len(o.CompactionTotalSizeMultiplierPerLevel) && o.CompactionTotalSizeMultiplierPerLevel[level] > 0 {
+			mult = o.CompactionTotalSizeMultiplierPerLevel[level]
+		} else if o.CompactionTotalSizeMultiplier > 0 {
+			mult = math.Pow(o.CompactionTotalSizeMultiplier, float64(level))
+		}
+	}
+	if mult == 0 {
+		mult = math.Pow(DefaultCompactionTotalSizeMultiplier, float64(level))
+	}
+	return int64(float64(base) * mult)
+}
+
+func (o *Options) GetComparer() comparer.Comparer {
+	if o == nil || o.Comparer == nil {
+		return comparer.DefaultComparer
+	}
+	return o.Comparer
+}
+
+func (o *Options) GetCompression() Compression {
+	if o == nil || o.Compression <= DefaultCompression || o.Compression >= nCompression {
+		return DefaultCompressionType
+	}
+	return o.Compression
+}
+
+func (o *Options) GetDisableBufferPool() bool {
+	if o == nil {
+		return false
+	}
+	return o.DisableBufferPool
+}
+
+func (o *Options) GetDisableBlockCache() bool {
+	if o == nil {
+		return false
+	}
+	return o.DisableBlockCache
+}
+
+func (o *Options) GetDisableCompactionBackoff() bool {
+	if o == nil {
+		return false
+	}
+	return o.DisableCompactionBackoff
+}
+
+func (o *Options) GetDisableLargeBatchTransaction() bool {
+	if o == nil {
+		return false
+	}
+	return o.DisableLargeBatchTransaction
+}
+
+func (o *Options) GetErrorIfExist() bool {
+	if o == nil {
+		return false
+	}
+	return o.ErrorIfExist
+}
+
+func (o *Options) GetErrorIfMissing() bool {
+	if o == nil {
+		return false
+	}
+	return o.ErrorIfMissing
+}
+
+func (o *Options) GetFilter() filter.Filter {
+	if o == nil {
+		return nil
+	}
+	return o.Filter
+}
+
+func (o *Options) GetIteratorSamplingRate() int {
+	if o == nil || o.IteratorSamplingRate <= 0 {
+		return DefaultIteratorSamplingRate
+	}
+	return o.IteratorSamplingRate
+}
+
+func (o *Options) GetNoSync() bool {
+	if o == nil {
+		return false
+	}
+	return o.NoSync
+}
+
+func (o *Options) GetNoWriteMerge() bool {
+	if o == nil {
+		return false
+	}
+	return o.NoWriteMerge
+}
+
+func (o *Options) GetOpenFilesCacher() Cacher {
+	if o == nil || o.OpenFilesCacher == nil {
+		return DefaultOpenFilesCacher
+	}
+	if o.OpenFilesCacher == NoCacher {
+		return nil
+	}
+	return o.OpenFilesCacher
+}
+
+func (o *Options) GetOpenFilesCacheCapacity() int {
+	if o == nil || o.OpenFilesCacheCapacity == 0 {
+		return DefaultOpenFilesCacheCapacity
+	} else if o.OpenFilesCacheCapacity < 0 {
+		return 0
+	}
+	return o.OpenFilesCacheCapacity
+}
+
+func (o *Options) GetReadOnly() bool {
+	if o == nil {
+		return false
+	}
+	return o.ReadOnly
+}
+
+func (o *Options) GetStrict(strict Strict) bool {
+	if o == nil || o.Strict == 0 {
+		return DefaultStrict&strict != 0
+	}
+	return o.Strict&strict != 0
+}
+
+func (o *Options) GetWriteBuffer() int {
+	if o == nil || o.WriteBuffer <= 0 {
+		return DefaultWriteBuffer
+	}
+	return o.WriteBuffer
+}
+
+func (o *Options) GetWriteL0PauseTrigger() int {
+	if o == nil || o.WriteL0PauseTrigger == 0 {
+		return DefaultWriteL0PauseTrigger
+	}
+	return o.WriteL0PauseTrigger
+}
+
+func (o *Options) GetWriteL0SlowdownTrigger() int {
+	if o == nil || o.WriteL0SlowdownTrigger == 0 {
+		return DefaultWriteL0SlowdownTrigger
+	}
+	return o.WriteL0SlowdownTrigger
+}
+
+// ReadOptions holds the optional parameters for 'read operation'. The
+// 'read operation' includes Get, Find and NewIterator.
+type ReadOptions struct {
+	// DontFillCache defines whether block reads for this 'read operation'
+	// should be cached. If false then the block will be cached. This does
+	// not affects already cached block.
+	//
+	// The default value is false.
+	DontFillCache bool
+
+	// Strict will be OR'ed with global DB 'strict level' unless StrictOverride
+	// is present. Currently only StrictReader that has effect here.
+	Strict Strict
+}
+
+func (ro *ReadOptions) GetDontFillCache() bool {
+	if ro == nil {
+		return false
+	}
+	return ro.DontFillCache
+}
+
+func (ro *ReadOptions) GetStrict(strict Strict) bool {
+	if ro == nil {
+		return false
+	}
+	return ro.Strict&strict != 0
+}
+
+// WriteOptions holds the optional parameters for 'write operation'. The
+// 'write operation' includes Write, Put and Delete.
+type WriteOptions struct {
+	// NoWriteMerge allows disabling write merge.
+	//
+	// The default is false.
+	NoWriteMerge bool
+
+	// Sync is whether to sync underlying writes from the OS buffer cache
+	// through to actual disk, if applicable. Setting Sync can result in
+	// slower writes.
+	//
+	// If false, and the machine crashes, then some recent writes may be lost.
+	// Note that if it is just the process that crashes (and the machine does
+	// not) then no writes will be lost.
+	//
+	// In other words, Sync being false has the same semantics as a write
+	// system call. Sync being true means write followed by fsync.
+	//
+	// The default value is false.
+	Sync bool
+}
+
+func (wo *WriteOptions) GetNoWriteMerge() bool {
+	if wo == nil {
+		return false
+	}
+	return wo.NoWriteMerge
+}
+
+func (wo *WriteOptions) GetSync() bool {
+	if wo == nil {
+		return false
+	}
+	return wo.Sync
+}
+
+func GetStrict(o *Options, ro *ReadOptions, strict Strict) bool {
+	if ro.GetStrict(StrictOverride) {
+		return ro.GetStrict(strict)
+	} else {
+		return o.GetStrict(strict) || ro.GetStrict(strict)
+	}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/options.go b/vendor/github.com/syndtr/goleveldb/leveldb/options.go
new file mode 100644
index 0000000000..b072b1ac4c
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/options.go
@@ -0,0 +1,107 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/filter"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+)
+
+func dupOptions(o *opt.Options) *opt.Options {
+	newo := &opt.Options{}
+	if o != nil {
+		*newo = *o
+	}
+	if newo.Strict == 0 {
+		newo.Strict = opt.DefaultStrict
+	}
+	return newo
+}
+
+func (s *session) setOptions(o *opt.Options) {
+	no := dupOptions(o)
+	// Alternative filters.
+	if filters := o.GetAltFilters(); len(filters) > 0 {
+		no.AltFilters = make([]filter.Filter, len(filters))
+		for i, filter := range filters {
+			no.AltFilters[i] = &iFilter{filter}
+		}
+	}
+	// Comparer.
+	s.icmp = &iComparer{o.GetComparer()}
+	no.Comparer = s.icmp
+	// Filter.
+	if filter := o.GetFilter(); filter != nil {
+		no.Filter = &iFilter{filter}
+	}
+
+	s.o = &cachedOptions{Options: no}
+	s.o.cache()
+}
+
+const optCachedLevel = 7
+
+type cachedOptions struct {
+	*opt.Options
+
+	compactionExpandLimit []int
+	compactionGPOverlaps  []int
+	compactionSourceLimit []int
+	compactionTableSize   []int
+	compactionTotalSize   []int64
+}
+
+func (co *cachedOptions) cache() {
+	co.compactionExpandLimit = make([]int, optCachedLevel)
+	co.compactionGPOverlaps = make([]int, optCachedLevel)
+	co.compactionSourceLimit = make([]int, optCachedLevel)
+	co.compactionTableSize = make([]int, optCachedLevel)
+	co.compactionTotalSize = make([]int64, optCachedLevel)
+
+	for level := 0; level < optCachedLevel; level++ {
+		co.compactionExpandLimit[level] = co.Options.GetCompactionExpandLimit(level)
+		co.compactionGPOverlaps[level] = co.Options.GetCompactionGPOverlaps(level)
+		co.compactionSourceLimit[level] = co.Options.GetCompactionSourceLimit(level)
+		co.compactionTableSize[level] = co.Options.GetCompactionTableSize(level)
+		co.compactionTotalSize[level] = co.Options.GetCompactionTotalSize(level)
+	}
+}
+
+func (co *cachedOptions) GetCompactionExpandLimit(level int) int {
+	if level < optCachedLevel {
+		return co.compactionExpandLimit[level]
+	}
+	return co.Options.GetCompactionExpandLimit(level)
+}
+
+func (co *cachedOptions) GetCompactionGPOverlaps(level int) int {
+	if level < optCachedLevel {
+		return co.compactionGPOverlaps[level]
+	}
+	return co.Options.GetCompactionGPOverlaps(level)
+}
+
+func (co *cachedOptions) GetCompactionSourceLimit(level int) int {
+	if level < optCachedLevel {
+		return co.compactionSourceLimit[level]
+	}
+	return co.Options.GetCompactionSourceLimit(level)
+}
+
+func (co *cachedOptions) GetCompactionTableSize(level int) int {
+	if level < optCachedLevel {
+		return co.compactionTableSize[level]
+	}
+	return co.Options.GetCompactionTableSize(level)
+}
+
+func (co *cachedOptions) GetCompactionTotalSize(level int) int64 {
+	if level < optCachedLevel {
+		return co.compactionTotalSize[level]
+	}
+	return co.Options.GetCompactionTotalSize(level)
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/session.go b/vendor/github.com/syndtr/goleveldb/leveldb/session.go
new file mode 100644
index 0000000000..3f391f9346
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/session.go
@@ -0,0 +1,210 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"fmt"
+	"io"
+	"os"
+	"sync"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/journal"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+// ErrManifestCorrupted records manifest corruption. This error will be
+// wrapped with errors.ErrCorrupted.
+type ErrManifestCorrupted struct {
+	Field  string
+	Reason string
+}
+
+func (e *ErrManifestCorrupted) Error() string {
+	return fmt.Sprintf("leveldb: manifest corrupted (field '%s'): %s", e.Field, e.Reason)
+}
+
+func newErrManifestCorrupted(fd storage.FileDesc, field, reason string) error {
+	return errors.NewErrCorrupted(fd, &ErrManifestCorrupted{field, reason})
+}
+
+// session represent a persistent database session.
+type session struct {
+	// Need 64-bit alignment.
+	stNextFileNum    int64 // current unused file number
+	stJournalNum     int64 // current journal file number; need external synchronization
+	stPrevJournalNum int64 // prev journal file number; no longer used; for compatibility with older version of leveldb
+	stTempFileNum    int64
+	stSeqNum         uint64 // last mem compacted seq; need external synchronization
+
+	stor     *iStorage
+	storLock storage.Locker
+	o        *cachedOptions
+	icmp     *iComparer
+	tops     *tOps
+	fileRef  map[int64]int
+
+	manifest       *journal.Writer
+	manifestWriter storage.Writer
+	manifestFd     storage.FileDesc
+
+	stCompPtrs []internalKey // compaction pointers; need external synchronization
+	stVersion  *version      // current version
+	vmu        sync.Mutex
+}
+
+// Creates new initialized session instance.
+func newSession(stor storage.Storage, o *opt.Options) (s *session, err error) {
+	if stor == nil {
+		return nil, os.ErrInvalid
+	}
+	storLock, err := stor.Lock()
+	if err != nil {
+		return
+	}
+	s = &session{
+		stor:     newIStorage(stor),
+		storLock: storLock,
+		fileRef:  make(map[int64]int),
+	}
+	s.setOptions(o)
+	s.tops = newTableOps(s)
+	s.setVersion(newVersion(s))
+	s.log("log@legend F·NumFile S·FileSize N·Entry C·BadEntry B·BadBlock Ke·KeyError D·DroppedEntry L·Level Q·SeqNum T·TimeElapsed")
+	return
+}
+
+// Close session.
+func (s *session) close() {
+	s.tops.close()
+	if s.manifest != nil {
+		s.manifest.Close()
+	}
+	if s.manifestWriter != nil {
+		s.manifestWriter.Close()
+	}
+	s.manifest = nil
+	s.manifestWriter = nil
+	s.setVersion(&version{s: s, closing: true})
+}
+
+// Release session lock.
+func (s *session) release() {
+	s.storLock.Unlock()
+}
+
+// Create a new database session; need external synchronization.
+func (s *session) create() error {
+	// create manifest
+	return s.newManifest(nil, nil)
+}
+
+// Recover a database session; need external synchronization.
+func (s *session) recover() (err error) {
+	defer func() {
+		if os.IsNotExist(err) {
+			// Don't return os.ErrNotExist if the underlying storage contains
+			// other files that belong to LevelDB. So the DB won't get trashed.
+			if fds, _ := s.stor.List(storage.TypeAll); len(fds) > 0 {
+				err = &errors.ErrCorrupted{Fd: storage.FileDesc{Type: storage.TypeManifest}, Err: &errors.ErrMissingFiles{}}
+			}
+		}
+	}()
+
+	fd, err := s.stor.GetMeta()
+	if err != nil {
+		return
+	}
+
+	reader, err := s.stor.Open(fd)
+	if err != nil {
+		return
+	}
+	defer reader.Close()
+
+	var (
+		// Options.
+		strict = s.o.GetStrict(opt.StrictManifest)
+
+		jr      = journal.NewReader(reader, dropper{s, fd}, strict, true)
+		rec     = &sessionRecord{}
+		staging = s.stVersion.newStaging()
+	)
+	for {
+		var r io.Reader
+		r, err = jr.Next()
+		if err != nil {
+			if err == io.EOF {
+				err = nil
+				break
+			}
+			return errors.SetFd(err, fd)
+		}
+
+		err = rec.decode(r)
+		if err == nil {
+			// save compact pointers
+			for _, r := range rec.compPtrs {
+				s.setCompPtr(r.level, internalKey(r.ikey))
+			}
+			// commit record to version staging
+			staging.commit(rec)
+		} else {
+			err = errors.SetFd(err, fd)
+			if strict || !errors.IsCorrupted(err) {
+				return
+			}
+			s.logf("manifest error: %v (skipped)", errors.SetFd(err, fd))
+		}
+		rec.resetCompPtrs()
+		rec.resetAddedTables()
+		rec.resetDeletedTables()
+	}
+
+	switch {
+	case !rec.has(recComparer):
+		return newErrManifestCorrupted(fd, "comparer", "missing")
+	case rec.comparer != s.icmp.uName():
+		return newErrManifestCorrupted(fd, "comparer", fmt.Sprintf("mismatch: want '%s', got '%s'", s.icmp.uName(), rec.comparer))
+	case !rec.has(recNextFileNum):
+		return newErrManifestCorrupted(fd, "next-file-num", "missing")
+	case !rec.has(recJournalNum):
+		return newErrManifestCorrupted(fd, "journal-file-num", "missing")
+	case !rec.has(recSeqNum):
+		return newErrManifestCorrupted(fd, "seq-num", "missing")
+	}
+
+	s.manifestFd = fd
+	s.setVersion(staging.finish())
+	s.setNextFileNum(rec.nextFileNum)
+	s.recordCommited(rec)
+	return nil
+}
+
+// Commit session; need external synchronization.
+func (s *session) commit(r *sessionRecord) (err error) {
+	v := s.version()
+	defer v.release()
+
+	// spawn new version based on current version
+	nv := v.spawn(r)
+
+	if s.manifest == nil {
+		// manifest journal writer not yet created, create one
+		err = s.newManifest(r, nv)
+	} else {
+		err = s.flushManifest(r)
+	}
+
+	// finally, apply new version if no error rise
+	if err == nil {
+		s.setVersion(nv)
+	}
+
+	return
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/session_compaction.go b/vendor/github.com/syndtr/goleveldb/leveldb/session_compaction.go
new file mode 100644
index 0000000000..089cd00b26
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/session_compaction.go
@@ -0,0 +1,302 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"sync/atomic"
+
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/memdb"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+)
+
+func (s *session) pickMemdbLevel(umin, umax []byte, maxLevel int) int {
+	v := s.version()
+	defer v.release()
+	return v.pickMemdbLevel(umin, umax, maxLevel)
+}
+
+func (s *session) flushMemdb(rec *sessionRecord, mdb *memdb.DB, maxLevel int) (int, error) {
+	// Create sorted table.
+	iter := mdb.NewIterator(nil)
+	defer iter.Release()
+	t, n, err := s.tops.createFrom(iter)
+	if err != nil {
+		return 0, err
+	}
+
+	// Pick level other than zero can cause compaction issue with large
+	// bulk insert and delete on strictly incrementing key-space. The
+	// problem is that the small deletion markers trapped at lower level,
+	// while key/value entries keep growing at higher level. Since the
+	// key-space is strictly incrementing it will not overlaps with
+	// higher level, thus maximum possible level is always picked, while
+	// overlapping deletion marker pushed into lower level.
+	// See: https://github.com/syndtr/goleveldb/issues/127.
+	flushLevel := s.pickMemdbLevel(t.imin.ukey(), t.imax.ukey(), maxLevel)
+	rec.addTableFile(flushLevel, t)
+
+	s.logf("memdb@flush created L%d@%d N·%d S·%s %q:%q", flushLevel, t.fd.Num, n, shortenb(int(t.size)), t.imin, t.imax)
+	return flushLevel, nil
+}
+
+// Pick a compaction based on current state; need external synchronization.
+func (s *session) pickCompaction() *compaction {
+	v := s.version()
+
+	var sourceLevel int
+	var t0 tFiles
+	if v.cScore >= 1 {
+		sourceLevel = v.cLevel
+		cptr := s.getCompPtr(sourceLevel)
+		tables := v.levels[sourceLevel]
+		for _, t := range tables {
+			if cptr == nil || s.icmp.Compare(t.imax, cptr) > 0 {
+				t0 = append(t0, t)
+				break
+			}
+		}
+		if len(t0) == 0 {
+			t0 = append(t0, tables[0])
+		}
+	} else {
+		if p := atomic.LoadPointer(&v.cSeek); p != nil {
+			ts := (*tSet)(p)
+			sourceLevel = ts.level
+			t0 = append(t0, ts.table)
+		} else {
+			v.release()
+			return nil
+		}
+	}
+
+	return newCompaction(s, v, sourceLevel, t0)
+}
+
+// Create compaction from given level and range; need external synchronization.
+func (s *session) getCompactionRange(sourceLevel int, umin, umax []byte, noLimit bool) *compaction {
+	v := s.version()
+
+	if sourceLevel >= len(v.levels) {
+		v.release()
+		return nil
+	}
+
+	t0 := v.levels[sourceLevel].getOverlaps(nil, s.icmp, umin, umax, sourceLevel == 0)
+	if len(t0) == 0 {
+		v.release()
+		return nil
+	}
+
+	// Avoid compacting too much in one shot in case the range is large.
+	// But we cannot do this for level-0 since level-0 files can overlap
+	// and we must not pick one file and drop another older file if the
+	// two files overlap.
+	if !noLimit && sourceLevel > 0 {
+		limit := int64(v.s.o.GetCompactionSourceLimit(sourceLevel))
+		total := int64(0)
+		for i, t := range t0 {
+			total += t.size
+			if total >= limit {
+				s.logf("table@compaction limiting F·%d -> F·%d", len(t0), i+1)
+				t0 = t0[:i+1]
+				break
+			}
+		}
+	}
+
+	return newCompaction(s, v, sourceLevel, t0)
+}
+
+func newCompaction(s *session, v *version, sourceLevel int, t0 tFiles) *compaction {
+	c := &compaction{
+		s:             s,
+		v:             v,
+		sourceLevel:   sourceLevel,
+		levels:        [2]tFiles{t0, nil},
+		maxGPOverlaps: int64(s.o.GetCompactionGPOverlaps(sourceLevel)),
+		tPtrs:         make([]int, len(v.levels)),
+	}
+	c.expand()
+	c.save()
+	return c
+}
+
+// compaction represent a compaction state.
+type compaction struct {
+	s *session
+	v *version
+
+	sourceLevel   int
+	levels        [2]tFiles
+	maxGPOverlaps int64
+
+	gp                tFiles
+	gpi               int
+	seenKey           bool
+	gpOverlappedBytes int64
+	imin, imax        internalKey
+	tPtrs             []int
+	released          bool
+
+	snapGPI               int
+	snapSeenKey           bool
+	snapGPOverlappedBytes int64
+	snapTPtrs             []int
+}
+
+func (c *compaction) save() {
+	c.snapGPI = c.gpi
+	c.snapSeenKey = c.seenKey
+	c.snapGPOverlappedBytes = c.gpOverlappedBytes
+	c.snapTPtrs = append(c.snapTPtrs[:0], c.tPtrs...)
+}
+
+func (c *compaction) restore() {
+	c.gpi = c.snapGPI
+	c.seenKey = c.snapSeenKey
+	c.gpOverlappedBytes = c.snapGPOverlappedBytes
+	c.tPtrs = append(c.tPtrs[:0], c.snapTPtrs...)
+}
+
+func (c *compaction) release() {
+	if !c.released {
+		c.released = true
+		c.v.release()
+	}
+}
+
+// Expand compacted tables; need external synchronization.
+func (c *compaction) expand() {
+	limit := int64(c.s.o.GetCompactionExpandLimit(c.sourceLevel))
+	vt0 := c.v.levels[c.sourceLevel]
+	vt1 := tFiles{}
+	if level := c.sourceLevel + 1; level < len(c.v.levels) {
+		vt1 = c.v.levels[level]
+	}
+
+	t0, t1 := c.levels[0], c.levels[1]
+	imin, imax := t0.getRange(c.s.icmp)
+	// We expand t0 here just incase ukey hop across tables.
+	t0 = vt0.getOverlaps(t0, c.s.icmp, imin.ukey(), imax.ukey(), c.sourceLevel == 0)
+	if len(t0) != len(c.levels[0]) {
+		imin, imax = t0.getRange(c.s.icmp)
+	}
+	t1 = vt1.getOverlaps(t1, c.s.icmp, imin.ukey(), imax.ukey(), false)
+	// Get entire range covered by compaction.
+	amin, amax := append(t0, t1...).getRange(c.s.icmp)
+
+	// See if we can grow the number of inputs in "sourceLevel" without
+	// changing the number of "sourceLevel+1" files we pick up.
+	if len(t1) > 0 {
+		exp0 := vt0.getOverlaps(nil, c.s.icmp, amin.ukey(), amax.ukey(), c.sourceLevel == 0)
+		if len(exp0) > len(t0) && t1.size()+exp0.size() < limit {
+			xmin, xmax := exp0.getRange(c.s.icmp)
+			exp1 := vt1.getOverlaps(nil, c.s.icmp, xmin.ukey(), xmax.ukey(), false)
+			if len(exp1) == len(t1) {
+				c.s.logf("table@compaction expanding L%d+L%d (F·%d S·%s)+(F·%d S·%s) -> (F·%d S·%s)+(F·%d S·%s)",
+					c.sourceLevel, c.sourceLevel+1, len(t0), shortenb(int(t0.size())), len(t1), shortenb(int(t1.size())),
+					len(exp0), shortenb(int(exp0.size())), len(exp1), shortenb(int(exp1.size())))
+				imin, imax = xmin, xmax
+				t0, t1 = exp0, exp1
+				amin, amax = append(t0, t1...).getRange(c.s.icmp)
+			}
+		}
+	}
+
+	// Compute the set of grandparent files that overlap this compaction
+	// (parent == sourceLevel+1; grandparent == sourceLevel+2)
+	if level := c.sourceLevel + 2; level < len(c.v.levels) {
+		c.gp = c.v.levels[level].getOverlaps(c.gp, c.s.icmp, amin.ukey(), amax.ukey(), false)
+	}
+
+	c.levels[0], c.levels[1] = t0, t1
+	c.imin, c.imax = imin, imax
+}
+
+// Check whether compaction is trivial.
+func (c *compaction) trivial() bool {
+	return len(c.levels[0]) == 1 && len(c.levels[1]) == 0 && c.gp.size() <= c.maxGPOverlaps
+}
+
+func (c *compaction) baseLevelForKey(ukey []byte) bool {
+	for level := c.sourceLevel + 2; level < len(c.v.levels); level++ {
+		tables := c.v.levels[level]
+		for c.tPtrs[level] < len(tables) {
+			t := tables[c.tPtrs[level]]
+			if c.s.icmp.uCompare(ukey, t.imax.ukey()) <= 0 {
+				// We've advanced far enough.
+				if c.s.icmp.uCompare(ukey, t.imin.ukey()) >= 0 {
+					// Key falls in this file's range, so definitely not base level.
+					return false
+				}
+				break
+			}
+			c.tPtrs[level]++
+		}
+	}
+	return true
+}
+
+func (c *compaction) shouldStopBefore(ikey internalKey) bool {
+	for ; c.gpi < len(c.gp); c.gpi++ {
+		gp := c.gp[c.gpi]
+		if c.s.icmp.Compare(ikey, gp.imax) <= 0 {
+			break
+		}
+		if c.seenKey {
+			c.gpOverlappedBytes += gp.size
+		}
+	}
+	c.seenKey = true
+
+	if c.gpOverlappedBytes > c.maxGPOverlaps {
+		// Too much overlap for current output; start new output.
+		c.gpOverlappedBytes = 0
+		return true
+	}
+	return false
+}
+
+// Creates an iterator.
+func (c *compaction) newIterator() iterator.Iterator {
+	// Creates iterator slice.
+	icap := len(c.levels)
+	if c.sourceLevel == 0 {
+		// Special case for level-0.
+		icap = len(c.levels[0]) + 1
+	}
+	its := make([]iterator.Iterator, 0, icap)
+
+	// Options.
+	ro := &opt.ReadOptions{
+		DontFillCache: true,
+		Strict:        opt.StrictOverride,
+	}
+	strict := c.s.o.GetStrict(opt.StrictCompaction)
+	if strict {
+		ro.Strict |= opt.StrictReader
+	}
+
+	for i, tables := range c.levels {
+		if len(tables) == 0 {
+			continue
+		}
+
+		// Level-0 is not sorted and may overlaps each other.
+		if c.sourceLevel+i == 0 {
+			for _, t := range tables {
+				its = append(its, c.s.tops.newIterator(t, nil, ro))
+			}
+		} else {
+			it := iterator.NewIndexedIterator(tables.newIndexIterator(c.s.tops, c.s.icmp, nil, ro), strict)
+			its = append(its, it)
+		}
+	}
+
+	return iterator.NewMergedIterator(its, c.s.icmp, strict)
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/session_record.go b/vendor/github.com/syndtr/goleveldb/leveldb/session_record.go
new file mode 100644
index 0000000000..854e1aa6f9
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/session_record.go
@@ -0,0 +1,323 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"bufio"
+	"encoding/binary"
+	"io"
+	"strings"
+
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+type byteReader interface {
+	io.Reader
+	io.ByteReader
+}
+
+// These numbers are written to disk and should not be changed.
+const (
+	recComparer    = 1
+	recJournalNum  = 2
+	recNextFileNum = 3
+	recSeqNum      = 4
+	recCompPtr     = 5
+	recDelTable    = 6
+	recAddTable    = 7
+	// 8 was used for large value refs
+	recPrevJournalNum = 9
+)
+
+type cpRecord struct {
+	level int
+	ikey  internalKey
+}
+
+type atRecord struct {
+	level int
+	num   int64
+	size  int64
+	imin  internalKey
+	imax  internalKey
+}
+
+type dtRecord struct {
+	level int
+	num   int64
+}
+
+type sessionRecord struct {
+	hasRec         int
+	comparer       string
+	journalNum     int64
+	prevJournalNum int64
+	nextFileNum    int64
+	seqNum         uint64
+	compPtrs       []cpRecord
+	addedTables    []atRecord
+	deletedTables  []dtRecord
+
+	scratch [binary.MaxVarintLen64]byte
+	err     error
+}
+
+func (p *sessionRecord) has(rec int) bool {
+	return p.hasRec&(1<<uint(rec)) != 0
+}
+
+func (p *sessionRecord) setComparer(name string) {
+	p.hasRec |= 1 << recComparer
+	p.comparer = name
+}
+
+func (p *sessionRecord) setJournalNum(num int64) {
+	p.hasRec |= 1 << recJournalNum
+	p.journalNum = num
+}
+
+func (p *sessionRecord) setPrevJournalNum(num int64) {
+	p.hasRec |= 1 << recPrevJournalNum
+	p.prevJournalNum = num
+}
+
+func (p *sessionRecord) setNextFileNum(num int64) {
+	p.hasRec |= 1 << recNextFileNum
+	p.nextFileNum = num
+}
+
+func (p *sessionRecord) setSeqNum(num uint64) {
+	p.hasRec |= 1 << recSeqNum
+	p.seqNum = num
+}
+
+func (p *sessionRecord) addCompPtr(level int, ikey internalKey) {
+	p.hasRec |= 1 << recCompPtr
+	p.compPtrs = append(p.compPtrs, cpRecord{level, ikey})
+}
+
+func (p *sessionRecord) resetCompPtrs() {
+	p.hasRec &= ^(1 << recCompPtr)
+	p.compPtrs = p.compPtrs[:0]
+}
+
+func (p *sessionRecord) addTable(level int, num, size int64, imin, imax internalKey) {
+	p.hasRec |= 1 << recAddTable
+	p.addedTables = append(p.addedTables, atRecord{level, num, size, imin, imax})
+}
+
+func (p *sessionRecord) addTableFile(level int, t *tFile) {
+	p.addTable(level, t.fd.Num, t.size, t.imin, t.imax)
+}
+
+func (p *sessionRecord) resetAddedTables() {
+	p.hasRec &= ^(1 << recAddTable)
+	p.addedTables = p.addedTables[:0]
+}
+
+func (p *sessionRecord) delTable(level int, num int64) {
+	p.hasRec |= 1 << recDelTable
+	p.deletedTables = append(p.deletedTables, dtRecord{level, num})
+}
+
+func (p *sessionRecord) resetDeletedTables() {
+	p.hasRec &= ^(1 << recDelTable)
+	p.deletedTables = p.deletedTables[:0]
+}
+
+func (p *sessionRecord) putUvarint(w io.Writer, x uint64) {
+	if p.err != nil {
+		return
+	}
+	n := binary.PutUvarint(p.scratch[:], x)
+	_, p.err = w.Write(p.scratch[:n])
+}
+
+func (p *sessionRecord) putVarint(w io.Writer, x int64) {
+	if x < 0 {
+		panic("invalid negative value")
+	}
+	p.putUvarint(w, uint64(x))
+}
+
+func (p *sessionRecord) putBytes(w io.Writer, x []byte) {
+	if p.err != nil {
+		return
+	}
+	p.putUvarint(w, uint64(len(x)))
+	if p.err != nil {
+		return
+	}
+	_, p.err = w.Write(x)
+}
+
+func (p *sessionRecord) encode(w io.Writer) error {
+	p.err = nil
+	if p.has(recComparer) {
+		p.putUvarint(w, recComparer)
+		p.putBytes(w, []byte(p.comparer))
+	}
+	if p.has(recJournalNum) {
+		p.putUvarint(w, recJournalNum)
+		p.putVarint(w, p.journalNum)
+	}
+	if p.has(recNextFileNum) {
+		p.putUvarint(w, recNextFileNum)
+		p.putVarint(w, p.nextFileNum)
+	}
+	if p.has(recSeqNum) {
+		p.putUvarint(w, recSeqNum)
+		p.putUvarint(w, p.seqNum)
+	}
+	for _, r := range p.compPtrs {
+		p.putUvarint(w, recCompPtr)
+		p.putUvarint(w, uint64(r.level))
+		p.putBytes(w, r.ikey)
+	}
+	for _, r := range p.deletedTables {
+		p.putUvarint(w, recDelTable)
+		p.putUvarint(w, uint64(r.level))
+		p.putVarint(w, r.num)
+	}
+	for _, r := range p.addedTables {
+		p.putUvarint(w, recAddTable)
+		p.putUvarint(w, uint64(r.level))
+		p.putVarint(w, r.num)
+		p.putVarint(w, r.size)
+		p.putBytes(w, r.imin)
+		p.putBytes(w, r.imax)
+	}
+	return p.err
+}
+
+func (p *sessionRecord) readUvarintMayEOF(field string, r io.ByteReader, mayEOF bool) uint64 {
+	if p.err != nil {
+		return 0
+	}
+	x, err := binary.ReadUvarint(r)
+	if err != nil {
+		if err == io.ErrUnexpectedEOF || (mayEOF == false && err == io.EOF) {
+			p.err = errors.NewErrCorrupted(storage.FileDesc{}, &ErrManifestCorrupted{field, "short read"})
+		} else if strings.HasPrefix(err.Error(), "binary:") {
+			p.err = errors.NewErrCorrupted(storage.FileDesc{}, &ErrManifestCorrupted{field, err.Error()})
+		} else {
+			p.err = err
+		}
+		return 0
+	}
+	return x
+}
+
+func (p *sessionRecord) readUvarint(field string, r io.ByteReader) uint64 {
+	return p.readUvarintMayEOF(field, r, false)
+}
+
+func (p *sessionRecord) readVarint(field string, r io.ByteReader) int64 {
+	x := int64(p.readUvarintMayEOF(field, r, false))
+	if x < 0 {
+		p.err = errors.NewErrCorrupted(storage.FileDesc{}, &ErrManifestCorrupted{field, "invalid negative value"})
+	}
+	return x
+}
+
+func (p *sessionRecord) readBytes(field string, r byteReader) []byte {
+	if p.err != nil {
+		return nil
+	}
+	n := p.readUvarint(field, r)
+	if p.err != nil {
+		return nil
+	}
+	x := make([]byte, n)
+	_, p.err = io.ReadFull(r, x)
+	if p.err != nil {
+		if p.err == io.ErrUnexpectedEOF {
+			p.err = errors.NewErrCorrupted(storage.FileDesc{}, &ErrManifestCorrupted{field, "short read"})
+		}
+		return nil
+	}
+	return x
+}
+
+func (p *sessionRecord) readLevel(field string, r io.ByteReader) int {
+	if p.err != nil {
+		return 0
+	}
+	x := p.readUvarint(field, r)
+	if p.err != nil {
+		return 0
+	}
+	return int(x)
+}
+
+func (p *sessionRecord) decode(r io.Reader) error {
+	br, ok := r.(byteReader)
+	if !ok {
+		br = bufio.NewReader(r)
+	}
+	p.err = nil
+	for p.err == nil {
+		rec := p.readUvarintMayEOF("field-header", br, true)
+		if p.err != nil {
+			if p.err == io.EOF {
+				return nil
+			}
+			return p.err
+		}
+		switch rec {
+		case recComparer:
+			x := p.readBytes("comparer", br)
+			if p.err == nil {
+				p.setComparer(string(x))
+			}
+		case recJournalNum:
+			x := p.readVarint("journal-num", br)
+			if p.err == nil {
+				p.setJournalNum(x)
+			}
+		case recPrevJournalNum:
+			x := p.readVarint("prev-journal-num", br)
+			if p.err == nil {
+				p.setPrevJournalNum(x)
+			}
+		case recNextFileNum:
+			x := p.readVarint("next-file-num", br)
+			if p.err == nil {
+				p.setNextFileNum(x)
+			}
+		case recSeqNum:
+			x := p.readUvarint("seq-num", br)
+			if p.err == nil {
+				p.setSeqNum(x)
+			}
+		case recCompPtr:
+			level := p.readLevel("comp-ptr.level", br)
+			ikey := p.readBytes("comp-ptr.ikey", br)
+			if p.err == nil {
+				p.addCompPtr(level, internalKey(ikey))
+			}
+		case recAddTable:
+			level := p.readLevel("add-table.level", br)
+			num := p.readVarint("add-table.num", br)
+			size := p.readVarint("add-table.size", br)
+			imin := p.readBytes("add-table.imin", br)
+			imax := p.readBytes("add-table.imax", br)
+			if p.err == nil {
+				p.addTable(level, num, size, imin, imax)
+			}
+		case recDelTable:
+			level := p.readLevel("del-table.level", br)
+			num := p.readVarint("del-table.num", br)
+			if p.err == nil {
+				p.delTable(level, num)
+			}
+		}
+	}
+
+	return p.err
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/session_util.go b/vendor/github.com/syndtr/goleveldb/leveldb/session_util.go
new file mode 100644
index 0000000000..40cb2cf957
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/session_util.go
@@ -0,0 +1,271 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"fmt"
+	"sync/atomic"
+
+	"github.com/syndtr/goleveldb/leveldb/journal"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+// Logging.
+
+type dropper struct {
+	s  *session
+	fd storage.FileDesc
+}
+
+func (d dropper) Drop(err error) {
+	if e, ok := err.(*journal.ErrCorrupted); ok {
+		d.s.logf("journal@drop %s-%d S·%s %q", d.fd.Type, d.fd.Num, shortenb(e.Size), e.Reason)
+	} else {
+		d.s.logf("journal@drop %s-%d %q", d.fd.Type, d.fd.Num, err)
+	}
+}
+
+func (s *session) log(v ...interface{})                 { s.stor.Log(fmt.Sprint(v...)) }
+func (s *session) logf(format string, v ...interface{}) { s.stor.Log(fmt.Sprintf(format, v...)) }
+
+// File utils.
+
+func (s *session) newTemp() storage.FileDesc {
+	num := atomic.AddInt64(&s.stTempFileNum, 1) - 1
+	return storage.FileDesc{Type: storage.TypeTemp, Num: num}
+}
+
+func (s *session) addFileRef(fd storage.FileDesc, ref int) int {
+	ref += s.fileRef[fd.Num]
+	if ref > 0 {
+		s.fileRef[fd.Num] = ref
+	} else if ref == 0 {
+		delete(s.fileRef, fd.Num)
+	} else {
+		panic(fmt.Sprintf("negative ref: %v", fd))
+	}
+	return ref
+}
+
+// Session state.
+
+// Get current version. This will incr version ref, must call
+// version.release (exactly once) after use.
+func (s *session) version() *version {
+	s.vmu.Lock()
+	defer s.vmu.Unlock()
+	s.stVersion.incref()
+	return s.stVersion
+}
+
+func (s *session) tLen(level int) int {
+	s.vmu.Lock()
+	defer s.vmu.Unlock()
+	return s.stVersion.tLen(level)
+}
+
+// Set current version to v.
+func (s *session) setVersion(v *version) {
+	s.vmu.Lock()
+	defer s.vmu.Unlock()
+	// Hold by session. It is important to call this first before releasing
+	// current version, otherwise the still used files might get released.
+	v.incref()
+	if s.stVersion != nil {
+		// Release current version.
+		s.stVersion.releaseNB()
+	}
+	s.stVersion = v
+}
+
+// Get current unused file number.
+func (s *session) nextFileNum() int64 {
+	return atomic.LoadInt64(&s.stNextFileNum)
+}
+
+// Set current unused file number to num.
+func (s *session) setNextFileNum(num int64) {
+	atomic.StoreInt64(&s.stNextFileNum, num)
+}
+
+// Mark file number as used.
+func (s *session) markFileNum(num int64) {
+	nextFileNum := num + 1
+	for {
+		old, x := s.stNextFileNum, nextFileNum
+		if old > x {
+			x = old
+		}
+		if atomic.CompareAndSwapInt64(&s.stNextFileNum, old, x) {
+			break
+		}
+	}
+}
+
+// Allocate a file number.
+func (s *session) allocFileNum() int64 {
+	return atomic.AddInt64(&s.stNextFileNum, 1) - 1
+}
+
+// Reuse given file number.
+func (s *session) reuseFileNum(num int64) {
+	for {
+		old, x := s.stNextFileNum, num
+		if old != x+1 {
+			x = old
+		}
+		if atomic.CompareAndSwapInt64(&s.stNextFileNum, old, x) {
+			break
+		}
+	}
+}
+
+// Set compaction ptr at given level; need external synchronization.
+func (s *session) setCompPtr(level int, ik internalKey) {
+	if level >= len(s.stCompPtrs) {
+		newCompPtrs := make([]internalKey, level+1)
+		copy(newCompPtrs, s.stCompPtrs)
+		s.stCompPtrs = newCompPtrs
+	}
+	s.stCompPtrs[level] = append(internalKey{}, ik...)
+}
+
+// Get compaction ptr at given level; need external synchronization.
+func (s *session) getCompPtr(level int) internalKey {
+	if level >= len(s.stCompPtrs) {
+		return nil
+	}
+	return s.stCompPtrs[level]
+}
+
+// Manifest related utils.
+
+// Fill given session record obj with current states; need external
+// synchronization.
+func (s *session) fillRecord(r *sessionRecord, snapshot bool) {
+	r.setNextFileNum(s.nextFileNum())
+
+	if snapshot {
+		if !r.has(recJournalNum) {
+			r.setJournalNum(s.stJournalNum)
+		}
+
+		if !r.has(recSeqNum) {
+			r.setSeqNum(s.stSeqNum)
+		}
+
+		for level, ik := range s.stCompPtrs {
+			if ik != nil {
+				r.addCompPtr(level, ik)
+			}
+		}
+
+		r.setComparer(s.icmp.uName())
+	}
+}
+
+// Mark if record has been committed, this will update session state;
+// need external synchronization.
+func (s *session) recordCommited(rec *sessionRecord) {
+	if rec.has(recJournalNum) {
+		s.stJournalNum = rec.journalNum
+	}
+
+	if rec.has(recPrevJournalNum) {
+		s.stPrevJournalNum = rec.prevJournalNum
+	}
+
+	if rec.has(recSeqNum) {
+		s.stSeqNum = rec.seqNum
+	}
+
+	for _, r := range rec.compPtrs {
+		s.setCompPtr(r.level, internalKey(r.ikey))
+	}
+}
+
+// Create a new manifest file; need external synchronization.
+func (s *session) newManifest(rec *sessionRecord, v *version) (err error) {
+	fd := storage.FileDesc{Type: storage.TypeManifest, Num: s.allocFileNum()}
+	writer, err := s.stor.Create(fd)
+	if err != nil {
+		return
+	}
+	jw := journal.NewWriter(writer)
+
+	if v == nil {
+		v = s.version()
+		defer v.release()
+	}
+	if rec == nil {
+		rec = &sessionRecord{}
+	}
+	s.fillRecord(rec, true)
+	v.fillRecord(rec)
+
+	defer func() {
+		if err == nil {
+			s.recordCommited(rec)
+			if s.manifest != nil {
+				s.manifest.Close()
+			}
+			if s.manifestWriter != nil {
+				s.manifestWriter.Close()
+			}
+			if !s.manifestFd.Zero() {
+				s.stor.Remove(s.manifestFd)
+			}
+			s.manifestFd = fd
+			s.manifestWriter = writer
+			s.manifest = jw
+		} else {
+			writer.Close()
+			s.stor.Remove(fd)
+			s.reuseFileNum(fd.Num)
+		}
+	}()
+
+	w, err := jw.Next()
+	if err != nil {
+		return
+	}
+	err = rec.encode(w)
+	if err != nil {
+		return
+	}
+	err = jw.Flush()
+	if err != nil {
+		return
+	}
+	err = s.stor.SetMeta(fd)
+	return
+}
+
+// Flush record to disk.
+func (s *session) flushManifest(rec *sessionRecord) (err error) {
+	s.fillRecord(rec, false)
+	w, err := s.manifest.Next()
+	if err != nil {
+		return
+	}
+	err = rec.encode(w)
+	if err != nil {
+		return
+	}
+	err = s.manifest.Flush()
+	if err != nil {
+		return
+	}
+	if !s.o.GetNoSync() {
+		err = s.manifestWriter.Sync()
+		if err != nil {
+			return
+		}
+	}
+	s.recordCommited(rec)
+	return
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage.go
new file mode 100644
index 0000000000..d45fb5dfeb
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage.go
@@ -0,0 +1,63 @@
+package leveldb
+
+import (
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"sync/atomic"
+)
+
+type iStorage struct {
+	storage.Storage
+	read  uint64
+	write uint64
+}
+
+func (c *iStorage) Open(fd storage.FileDesc) (storage.Reader, error) {
+	r, err := c.Storage.Open(fd)
+	return &iStorageReader{r, c}, err
+}
+
+func (c *iStorage) Create(fd storage.FileDesc) (storage.Writer, error) {
+	w, err := c.Storage.Create(fd)
+	return &iStorageWriter{w, c}, err
+}
+
+func (c *iStorage) reads() uint64 {
+	return atomic.LoadUint64(&c.read)
+}
+
+func (c *iStorage) writes() uint64 {
+	return atomic.LoadUint64(&c.write)
+}
+
+// newIStorage returns the given storage wrapped by iStorage.
+func newIStorage(s storage.Storage) *iStorage {
+	return &iStorage{s, 0, 0}
+}
+
+type iStorageReader struct {
+	storage.Reader
+	c *iStorage
+}
+
+func (r *iStorageReader) Read(p []byte) (n int, err error) {
+	n, err = r.Reader.Read(p)
+	atomic.AddUint64(&r.c.read, uint64(n))
+	return n, err
+}
+
+func (r *iStorageReader) ReadAt(p []byte, off int64) (n int, err error) {
+	n, err = r.Reader.ReadAt(p, off)
+	atomic.AddUint64(&r.c.read, uint64(n))
+	return n, err
+}
+
+type iStorageWriter struct {
+	storage.Writer
+	c *iStorage
+}
+
+func (w *iStorageWriter) Write(p []byte) (n int, err error) {
+	n, err = w.Writer.Write(p)
+	atomic.AddUint64(&w.c.write, uint64(n))
+	return n, err
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage.go
new file mode 100644
index 0000000000..9ba71fd6d1
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage.go
@@ -0,0 +1,671 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reservefs.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package storage
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"runtime"
+	"sort"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+var (
+	errFileOpen = errors.New("leveldb/storage: file still open")
+	errReadOnly = errors.New("leveldb/storage: storage is read-only")
+)
+
+type fileLock interface {
+	release() error
+}
+
+type fileStorageLock struct {
+	fs *fileStorage
+}
+
+func (lock *fileStorageLock) Unlock() {
+	if lock.fs != nil {
+		lock.fs.mu.Lock()
+		defer lock.fs.mu.Unlock()
+		if lock.fs.slock == lock {
+			lock.fs.slock = nil
+		}
+	}
+}
+
+type int64Slice []int64
+
+func (p int64Slice) Len() int           { return len(p) }
+func (p int64Slice) Less(i, j int) bool { return p[i] < p[j] }
+func (p int64Slice) Swap(i, j int)      { p[i], p[j] = p[j], p[i] }
+
+func writeFileSynced(filename string, data []byte, perm os.FileMode) error {
+	f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, perm)
+	if err != nil {
+		return err
+	}
+	n, err := f.Write(data)
+	if err == nil && n < len(data) {
+		err = io.ErrShortWrite
+	}
+	if err1 := f.Sync(); err == nil {
+		err = err1
+	}
+	if err1 := f.Close(); err == nil {
+		err = err1
+	}
+	return err
+}
+
+const logSizeThreshold = 1024 * 1024 // 1 MiB
+
+// fileStorage is a file-system backed storage.
+type fileStorage struct {
+	path     string
+	readOnly bool
+
+	mu      sync.Mutex
+	flock   fileLock
+	slock   *fileStorageLock
+	logw    *os.File
+	logSize int64
+	buf     []byte
+	// Opened file counter; if open < 0 means closed.
+	open int
+	day  int
+}
+
+// OpenFile returns a new filesystem-backed storage implementation with the given
+// path. This also acquire a file lock, so any subsequent attempt to open the
+// same path will fail.
+//
+// The storage must be closed after use, by calling Close method.
+func OpenFile(path string, readOnly bool) (Storage, error) {
+	if fi, err := os.Stat(path); err == nil {
+		if !fi.IsDir() {
+			return nil, fmt.Errorf("leveldb/storage: open %s: not a directory", path)
+		}
+	} else if os.IsNotExist(err) && !readOnly {
+		if err := os.MkdirAll(path, 0755); err != nil {
+			return nil, err
+		}
+	} else {
+		return nil, err
+	}
+
+	flock, err := newFileLock(filepath.Join(path, "LOCK"), readOnly)
+	if err != nil {
+		return nil, err
+	}
+
+	defer func() {
+		if err != nil {
+			flock.release()
+		}
+	}()
+
+	var (
+		logw    *os.File
+		logSize int64
+	)
+	if !readOnly {
+		logw, err = os.OpenFile(filepath.Join(path, "LOG"), os.O_WRONLY|os.O_CREATE, 0644)
+		if err != nil {
+			return nil, err
+		}
+		logSize, err = logw.Seek(0, os.SEEK_END)
+		if err != nil {
+			logw.Close()
+			return nil, err
+		}
+	}
+
+	fs := &fileStorage{
+		path:     path,
+		readOnly: readOnly,
+		flock:    flock,
+		logw:     logw,
+		logSize:  logSize,
+	}
+	runtime.SetFinalizer(fs, (*fileStorage).Close)
+	return fs, nil
+}
+
+func (fs *fileStorage) Lock() (Locker, error) {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return nil, ErrClosed
+	}
+	if fs.readOnly {
+		return &fileStorageLock{}, nil
+	}
+	if fs.slock != nil {
+		return nil, ErrLocked
+	}
+	fs.slock = &fileStorageLock{fs: fs}
+	return fs.slock, nil
+}
+
+func itoa(buf []byte, i int, wid int) []byte {
+	u := uint(i)
+	if u == 0 && wid <= 1 {
+		return append(buf, '0')
+	}
+
+	// Assemble decimal in reverse order.
+	var b [32]byte
+	bp := len(b)
+	for ; u > 0 || wid > 0; u /= 10 {
+		bp--
+		wid--
+		b[bp] = byte(u%10) + '0'
+	}
+	return append(buf, b[bp:]...)
+}
+
+func (fs *fileStorage) printDay(t time.Time) {
+	if fs.day == t.Day() {
+		return
+	}
+	fs.day = t.Day()
+	fs.logw.Write([]byte("=============== " + t.Format("Jan 2, 2006 (MST)") + " ===============\n"))
+}
+
+func (fs *fileStorage) doLog(t time.Time, str string) {
+	if fs.logSize > logSizeThreshold {
+		// Rotate log file.
+		fs.logw.Close()
+		fs.logw = nil
+		fs.logSize = 0
+		rename(filepath.Join(fs.path, "LOG"), filepath.Join(fs.path, "LOG.old"))
+	}
+	if fs.logw == nil {
+		var err error
+		fs.logw, err = os.OpenFile(filepath.Join(fs.path, "LOG"), os.O_WRONLY|os.O_CREATE, 0644)
+		if err != nil {
+			return
+		}
+		// Force printDay on new log file.
+		fs.day = 0
+	}
+	fs.printDay(t)
+	hour, min, sec := t.Clock()
+	msec := t.Nanosecond() / 1e3
+	// time
+	fs.buf = itoa(fs.buf[:0], hour, 2)
+	fs.buf = append(fs.buf, ':')
+	fs.buf = itoa(fs.buf, min, 2)
+	fs.buf = append(fs.buf, ':')
+	fs.buf = itoa(fs.buf, sec, 2)
+	fs.buf = append(fs.buf, '.')
+	fs.buf = itoa(fs.buf, msec, 6)
+	fs.buf = append(fs.buf, ' ')
+	// write
+	fs.buf = append(fs.buf, []byte(str)...)
+	fs.buf = append(fs.buf, '\n')
+	n, _ := fs.logw.Write(fs.buf)
+	fs.logSize += int64(n)
+}
+
+func (fs *fileStorage) Log(str string) {
+	if !fs.readOnly {
+		t := time.Now()
+		fs.mu.Lock()
+		defer fs.mu.Unlock()
+		if fs.open < 0 {
+			return
+		}
+		fs.doLog(t, str)
+	}
+}
+
+func (fs *fileStorage) log(str string) {
+	if !fs.readOnly {
+		fs.doLog(time.Now(), str)
+	}
+}
+
+func (fs *fileStorage) setMeta(fd FileDesc) error {
+	content := fsGenName(fd) + "\n"
+	// Check and backup old CURRENT file.
+	currentPath := filepath.Join(fs.path, "CURRENT")
+	if _, err := os.Stat(currentPath); err == nil {
+		b, err := ioutil.ReadFile(currentPath)
+		if err != nil {
+			fs.log(fmt.Sprintf("backup CURRENT: %v", err))
+			return err
+		}
+		if string(b) == content {
+			// Content not changed, do nothing.
+			return nil
+		}
+		if err := writeFileSynced(currentPath+".bak", b, 0644); err != nil {
+			fs.log(fmt.Sprintf("backup CURRENT: %v", err))
+			return err
+		}
+	} else if !os.IsNotExist(err) {
+		return err
+	}
+	path := fmt.Sprintf("%s.%d", filepath.Join(fs.path, "CURRENT"), fd.Num)
+	if err := writeFileSynced(path, []byte(content), 0644); err != nil {
+		fs.log(fmt.Sprintf("create CURRENT.%d: %v", fd.Num, err))
+		return err
+	}
+	// Replace CURRENT file.
+	if err := rename(path, currentPath); err != nil {
+		fs.log(fmt.Sprintf("rename CURRENT.%d: %v", fd.Num, err))
+		return err
+	}
+	// Sync root directory.
+	if err := syncDir(fs.path); err != nil {
+		fs.log(fmt.Sprintf("syncDir: %v", err))
+		return err
+	}
+	return nil
+}
+
+func (fs *fileStorage) SetMeta(fd FileDesc) error {
+	if !FileDescOk(fd) {
+		return ErrInvalidFile
+	}
+	if fs.readOnly {
+		return errReadOnly
+	}
+
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return ErrClosed
+	}
+	return fs.setMeta(fd)
+}
+
+func (fs *fileStorage) GetMeta() (FileDesc, error) {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return FileDesc{}, ErrClosed
+	}
+	dir, err := os.Open(fs.path)
+	if err != nil {
+		return FileDesc{}, err
+	}
+	names, err := dir.Readdirnames(0)
+	// Close the dir first before checking for Readdirnames error.
+	if ce := dir.Close(); ce != nil {
+		fs.log(fmt.Sprintf("close dir: %v", ce))
+	}
+	if err != nil {
+		return FileDesc{}, err
+	}
+	// Try this in order:
+	// - CURRENT.[0-9]+ ('pending rename' file, descending order)
+	// - CURRENT
+	// - CURRENT.bak
+	//
+	// Skip corrupted file or file that point to a missing target file.
+	type currentFile struct {
+		name string
+		fd   FileDesc
+	}
+	tryCurrent := func(name string) (*currentFile, error) {
+		b, err := ioutil.ReadFile(filepath.Join(fs.path, name))
+		if err != nil {
+			if os.IsNotExist(err) {
+				err = os.ErrNotExist
+			}
+			return nil, err
+		}
+		var fd FileDesc
+		if len(b) < 1 || b[len(b)-1] != '\n' || !fsParseNamePtr(string(b[:len(b)-1]), &fd) {
+			fs.log(fmt.Sprintf("%s: corrupted content: %q", name, b))
+			err := &ErrCorrupted{
+				Err: errors.New("leveldb/storage: corrupted or incomplete CURRENT file"),
+			}
+			return nil, err
+		}
+		if _, err := os.Stat(filepath.Join(fs.path, fsGenName(fd))); err != nil {
+			if os.IsNotExist(err) {
+				fs.log(fmt.Sprintf("%s: missing target file: %s", name, fd))
+				err = os.ErrNotExist
+			}
+			return nil, err
+		}
+		return &currentFile{name: name, fd: fd}, nil
+	}
+	tryCurrents := func(names []string) (*currentFile, error) {
+		var (
+			cur *currentFile
+			// Last corruption error.
+			lastCerr error
+		)
+		for _, name := range names {
+			var err error
+			cur, err = tryCurrent(name)
+			if err == nil {
+				break
+			} else if err == os.ErrNotExist {
+				// Fallback to the next file.
+			} else if isCorrupted(err) {
+				lastCerr = err
+				// Fallback to the next file.
+			} else {
+				// In case the error is due to permission, etc.
+				return nil, err
+			}
+		}
+		if cur == nil {
+			err := os.ErrNotExist
+			if lastCerr != nil {
+				err = lastCerr
+			}
+			return nil, err
+		}
+		return cur, nil
+	}
+
+	// Try 'pending rename' files.
+	var nums []int64
+	for _, name := range names {
+		if strings.HasPrefix(name, "CURRENT.") && name != "CURRENT.bak" {
+			i, err := strconv.ParseInt(name[8:], 10, 64)
+			if err == nil {
+				nums = append(nums, i)
+			}
+		}
+	}
+	var (
+		pendCur   *currentFile
+		pendErr   = os.ErrNotExist
+		pendNames []string
+	)
+	if len(nums) > 0 {
+		sort.Sort(sort.Reverse(int64Slice(nums)))
+		pendNames = make([]string, len(nums))
+		for i, num := range nums {
+			pendNames[i] = fmt.Sprintf("CURRENT.%d", num)
+		}
+		pendCur, pendErr = tryCurrents(pendNames)
+		if pendErr != nil && pendErr != os.ErrNotExist && !isCorrupted(pendErr) {
+			return FileDesc{}, pendErr
+		}
+	}
+
+	// Try CURRENT and CURRENT.bak.
+	curCur, curErr := tryCurrents([]string{"CURRENT", "CURRENT.bak"})
+	if curErr != nil && curErr != os.ErrNotExist && !isCorrupted(curErr) {
+		return FileDesc{}, curErr
+	}
+
+	// pendCur takes precedence, but guards against obsolete pendCur.
+	if pendCur != nil && (curCur == nil || pendCur.fd.Num > curCur.fd.Num) {
+		curCur = pendCur
+	}
+
+	if curCur != nil {
+		// Restore CURRENT file to proper state.
+		if !fs.readOnly && (curCur.name != "CURRENT" || len(pendNames) != 0) {
+			// Ignore setMeta errors, however don't delete obsolete files if we
+			// catch error.
+			if err := fs.setMeta(curCur.fd); err == nil {
+				// Remove 'pending rename' files.
+				for _, name := range pendNames {
+					if err := os.Remove(filepath.Join(fs.path, name)); err != nil {
+						fs.log(fmt.Sprintf("remove %s: %v", name, err))
+					}
+				}
+			}
+		}
+		return curCur.fd, nil
+	}
+
+	// Nothing found.
+	if isCorrupted(pendErr) {
+		return FileDesc{}, pendErr
+	}
+	return FileDesc{}, curErr
+}
+
+func (fs *fileStorage) List(ft FileType) (fds []FileDesc, err error) {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return nil, ErrClosed
+	}
+	dir, err := os.Open(fs.path)
+	if err != nil {
+		return
+	}
+	names, err := dir.Readdirnames(0)
+	// Close the dir first before checking for Readdirnames error.
+	if cerr := dir.Close(); cerr != nil {
+		fs.log(fmt.Sprintf("close dir: %v", cerr))
+	}
+	if err == nil {
+		for _, name := range names {
+			if fd, ok := fsParseName(name); ok && fd.Type&ft != 0 {
+				fds = append(fds, fd)
+			}
+		}
+	}
+	return
+}
+
+func (fs *fileStorage) Open(fd FileDesc) (Reader, error) {
+	if !FileDescOk(fd) {
+		return nil, ErrInvalidFile
+	}
+
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return nil, ErrClosed
+	}
+	of, err := os.OpenFile(filepath.Join(fs.path, fsGenName(fd)), os.O_RDONLY, 0)
+	if err != nil {
+		if fsHasOldName(fd) && os.IsNotExist(err) {
+			of, err = os.OpenFile(filepath.Join(fs.path, fsGenOldName(fd)), os.O_RDONLY, 0)
+			if err == nil {
+				goto ok
+			}
+		}
+		return nil, err
+	}
+ok:
+	fs.open++
+	return &fileWrap{File: of, fs: fs, fd: fd}, nil
+}
+
+func (fs *fileStorage) Create(fd FileDesc) (Writer, error) {
+	if !FileDescOk(fd) {
+		return nil, ErrInvalidFile
+	}
+	if fs.readOnly {
+		return nil, errReadOnly
+	}
+
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return nil, ErrClosed
+	}
+	of, err := os.OpenFile(filepath.Join(fs.path, fsGenName(fd)), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return nil, err
+	}
+	fs.open++
+	return &fileWrap{File: of, fs: fs, fd: fd}, nil
+}
+
+func (fs *fileStorage) Remove(fd FileDesc) error {
+	if !FileDescOk(fd) {
+		return ErrInvalidFile
+	}
+	if fs.readOnly {
+		return errReadOnly
+	}
+
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return ErrClosed
+	}
+	err := os.Remove(filepath.Join(fs.path, fsGenName(fd)))
+	if err != nil {
+		if fsHasOldName(fd) && os.IsNotExist(err) {
+			if e1 := os.Remove(filepath.Join(fs.path, fsGenOldName(fd))); !os.IsNotExist(e1) {
+				fs.log(fmt.Sprintf("remove %s: %v (old name)", fd, err))
+				err = e1
+			}
+		} else {
+			fs.log(fmt.Sprintf("remove %s: %v", fd, err))
+		}
+	}
+	return err
+}
+
+func (fs *fileStorage) Rename(oldfd, newfd FileDesc) error {
+	if !FileDescOk(oldfd) || !FileDescOk(newfd) {
+		return ErrInvalidFile
+	}
+	if oldfd == newfd {
+		return nil
+	}
+	if fs.readOnly {
+		return errReadOnly
+	}
+
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return ErrClosed
+	}
+	return rename(filepath.Join(fs.path, fsGenName(oldfd)), filepath.Join(fs.path, fsGenName(newfd)))
+}
+
+func (fs *fileStorage) Close() error {
+	fs.mu.Lock()
+	defer fs.mu.Unlock()
+	if fs.open < 0 {
+		return ErrClosed
+	}
+	// Clear the finalizer.
+	runtime.SetFinalizer(fs, nil)
+
+	if fs.open > 0 {
+		fs.log(fmt.Sprintf("close: warning, %d files still open", fs.open))
+	}
+	fs.open = -1
+	if fs.logw != nil {
+		fs.logw.Close()
+	}
+	return fs.flock.release()
+}
+
+type fileWrap struct {
+	*os.File
+	fs     *fileStorage
+	fd     FileDesc
+	closed bool
+}
+
+func (fw *fileWrap) Sync() error {
+	if err := fw.File.Sync(); err != nil {
+		return err
+	}
+	if fw.fd.Type == TypeManifest {
+		// Also sync parent directory if file type is manifest.
+		// See: https://code.google.com/p/leveldb/issues/detail?id=190.
+		if err := syncDir(fw.fs.path); err != nil {
+			fw.fs.log(fmt.Sprintf("syncDir: %v", err))
+			return err
+		}
+	}
+	return nil
+}
+
+func (fw *fileWrap) Close() error {
+	fw.fs.mu.Lock()
+	defer fw.fs.mu.Unlock()
+	if fw.closed {
+		return ErrClosed
+	}
+	fw.closed = true
+	fw.fs.open--
+	err := fw.File.Close()
+	if err != nil {
+		fw.fs.log(fmt.Sprintf("close %s: %v", fw.fd, err))
+	}
+	return err
+}
+
+func fsGenName(fd FileDesc) string {
+	switch fd.Type {
+	case TypeManifest:
+		return fmt.Sprintf("MANIFEST-%06d", fd.Num)
+	case TypeJournal:
+		return fmt.Sprintf("%06d.log", fd.Num)
+	case TypeTable:
+		return fmt.Sprintf("%06d.ldb", fd.Num)
+	case TypeTemp:
+		return fmt.Sprintf("%06d.tmp", fd.Num)
+	default:
+		panic("invalid file type")
+	}
+}
+
+func fsHasOldName(fd FileDesc) bool {
+	return fd.Type == TypeTable
+}
+
+func fsGenOldName(fd FileDesc) string {
+	switch fd.Type {
+	case TypeTable:
+		return fmt.Sprintf("%06d.sst", fd.Num)
+	}
+	return fsGenName(fd)
+}
+
+func fsParseName(name string) (fd FileDesc, ok bool) {
+	var tail string
+	_, err := fmt.Sscanf(name, "%d.%s", &fd.Num, &tail)
+	if err == nil {
+		switch tail {
+		case "log":
+			fd.Type = TypeJournal
+		case "ldb", "sst":
+			fd.Type = TypeTable
+		case "tmp":
+			fd.Type = TypeTemp
+		default:
+			return
+		}
+		return fd, true
+	}
+	n, _ := fmt.Sscanf(name, "MANIFEST-%d%s", &fd.Num, &tail)
+	if n == 1 {
+		fd.Type = TypeManifest
+		return fd, true
+	}
+	return
+}
+
+func fsParseNamePtr(name string, fd *FileDesc) bool {
+	_fd, ok := fsParseName(name)
+	if fd != nil {
+		*fd = _fd
+	}
+	return ok
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_nacl.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_nacl.go
new file mode 100644
index 0000000000..5545aeef2a
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_nacl.go
@@ -0,0 +1,34 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// +build nacl
+
+package storage
+
+import (
+	"os"
+	"syscall"
+)
+
+func newFileLock(path string, readOnly bool) (fl fileLock, err error) {
+	return nil, syscall.ENOTSUP
+}
+
+func setFileLock(f *os.File, readOnly, lock bool) error {
+	return syscall.ENOTSUP
+}
+
+func rename(oldpath, newpath string) error {
+	return syscall.ENOTSUP
+}
+
+func isErrInvalid(err error) bool {
+	return false
+}
+
+func syncDir(name string) error {
+	return syscall.ENOTSUP
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_plan9.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_plan9.go
new file mode 100644
index 0000000000..b829798012
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_plan9.go
@@ -0,0 +1,63 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package storage
+
+import (
+	"os"
+)
+
+type plan9FileLock struct {
+	f *os.File
+}
+
+func (fl *plan9FileLock) release() error {
+	return fl.f.Close()
+}
+
+func newFileLock(path string, readOnly bool) (fl fileLock, err error) {
+	var (
+		flag int
+		perm os.FileMode
+	)
+	if readOnly {
+		flag = os.O_RDONLY
+	} else {
+		flag = os.O_RDWR
+		perm = os.ModeExclusive
+	}
+	f, err := os.OpenFile(path, flag, perm)
+	if os.IsNotExist(err) {
+		f, err = os.OpenFile(path, flag|os.O_CREATE, perm|0644)
+	}
+	if err != nil {
+		return
+	}
+	fl = &plan9FileLock{f: f}
+	return
+}
+
+func rename(oldpath, newpath string) error {
+	if _, err := os.Stat(newpath); err == nil {
+		if err := os.Remove(newpath); err != nil {
+			return err
+		}
+	}
+
+	return os.Rename(oldpath, newpath)
+}
+
+func syncDir(name string) error {
+	f, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	if err := f.Sync(); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_solaris.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_solaris.go
new file mode 100644
index 0000000000..79901ee4a7
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_solaris.go
@@ -0,0 +1,81 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// +build solaris
+
+package storage
+
+import (
+	"os"
+	"syscall"
+)
+
+type unixFileLock struct {
+	f *os.File
+}
+
+func (fl *unixFileLock) release() error {
+	if err := setFileLock(fl.f, false, false); err != nil {
+		return err
+	}
+	return fl.f.Close()
+}
+
+func newFileLock(path string, readOnly bool) (fl fileLock, err error) {
+	var flag int
+	if readOnly {
+		flag = os.O_RDONLY
+	} else {
+		flag = os.O_RDWR
+	}
+	f, err := os.OpenFile(path, flag, 0)
+	if os.IsNotExist(err) {
+		f, err = os.OpenFile(path, flag|os.O_CREATE, 0644)
+	}
+	if err != nil {
+		return
+	}
+	err = setFileLock(f, readOnly, true)
+	if err != nil {
+		f.Close()
+		return
+	}
+	fl = &unixFileLock{f: f}
+	return
+}
+
+func setFileLock(f *os.File, readOnly, lock bool) error {
+	flock := syscall.Flock_t{
+		Type:   syscall.F_UNLCK,
+		Start:  0,
+		Len:    0,
+		Whence: 1,
+	}
+	if lock {
+		if readOnly {
+			flock.Type = syscall.F_RDLCK
+		} else {
+			flock.Type = syscall.F_WRLCK
+		}
+	}
+	return syscall.FcntlFlock(f.Fd(), syscall.F_SETLK, &flock)
+}
+
+func rename(oldpath, newpath string) error {
+	return os.Rename(oldpath, newpath)
+}
+
+func syncDir(name string) error {
+	f, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	if err := f.Sync(); err != nil {
+		return err
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_unix.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_unix.go
new file mode 100644
index 0000000000..d75f66a9ef
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_unix.go
@@ -0,0 +1,98 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// +build darwin dragonfly freebsd linux netbsd openbsd
+
+package storage
+
+import (
+	"os"
+	"syscall"
+)
+
+type unixFileLock struct {
+	f *os.File
+}
+
+func (fl *unixFileLock) release() error {
+	if err := setFileLock(fl.f, false, false); err != nil {
+		return err
+	}
+	return fl.f.Close()
+}
+
+func newFileLock(path string, readOnly bool) (fl fileLock, err error) {
+	var flag int
+	if readOnly {
+		flag = os.O_RDONLY
+	} else {
+		flag = os.O_RDWR
+	}
+	f, err := os.OpenFile(path, flag, 0)
+	if os.IsNotExist(err) {
+		f, err = os.OpenFile(path, flag|os.O_CREATE, 0644)
+	}
+	if err != nil {
+		return
+	}
+	err = setFileLock(f, readOnly, true)
+	if err != nil {
+		f.Close()
+		return
+	}
+	fl = &unixFileLock{f: f}
+	return
+}
+
+func setFileLock(f *os.File, readOnly, lock bool) error {
+	how := syscall.LOCK_UN
+	if lock {
+		if readOnly {
+			how = syscall.LOCK_SH
+		} else {
+			how = syscall.LOCK_EX
+		}
+	}
+	return syscall.Flock(int(f.Fd()), how|syscall.LOCK_NB)
+}
+
+func rename(oldpath, newpath string) error {
+	return os.Rename(oldpath, newpath)
+}
+
+func isErrInvalid(err error) bool {
+	if err == os.ErrInvalid {
+		return true
+	}
+	// Go < 1.8
+	if syserr, ok := err.(*os.SyscallError); ok && syserr.Err == syscall.EINVAL {
+		return true
+	}
+	// Go >= 1.8 returns *os.PathError instead
+	if patherr, ok := err.(*os.PathError); ok && patherr.Err == syscall.EINVAL {
+		return true
+	}
+	return false
+}
+
+func syncDir(name string) error {
+	// As per fsync manpage, Linux seems to expect fsync on directory, however
+	// some system don't support this, so we will ignore syscall.EINVAL.
+	//
+	// From fsync(2):
+	//   Calling fsync() does not necessarily ensure that the entry in the
+	//   directory containing the file has also reached disk. For that an
+	//   explicit fsync() on a file descriptor for the directory is also needed.
+	f, err := os.Open(name)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	if err := f.Sync(); err != nil && !isErrInvalid(err) {
+		return err
+	}
+	return nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_windows.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_windows.go
new file mode 100644
index 0000000000..899335fd7e
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/file_storage_windows.go
@@ -0,0 +1,78 @@
+// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package storage
+
+import (
+	"syscall"
+	"unsafe"
+)
+
+var (
+	modkernel32 = syscall.NewLazyDLL("kernel32.dll")
+
+	procMoveFileExW = modkernel32.NewProc("MoveFileExW")
+)
+
+const (
+	_MOVEFILE_REPLACE_EXISTING = 1
+)
+
+type windowsFileLock struct {
+	fd syscall.Handle
+}
+
+func (fl *windowsFileLock) release() error {
+	return syscall.Close(fl.fd)
+}
+
+func newFileLock(path string, readOnly bool) (fl fileLock, err error) {
+	pathp, err := syscall.UTF16PtrFromString(path)
+	if err != nil {
+		return
+	}
+	var access, shareMode uint32
+	if readOnly {
+		access = syscall.GENERIC_READ
+		shareMode = syscall.FILE_SHARE_READ
+	} else {
+		access = syscall.GENERIC_READ | syscall.GENERIC_WRITE
+	}
+	fd, err := syscall.CreateFile(pathp, access, shareMode, nil, syscall.OPEN_EXISTING, syscall.FILE_ATTRIBUTE_NORMAL, 0)
+	if err == syscall.ERROR_FILE_NOT_FOUND {
+		fd, err = syscall.CreateFile(pathp, access, shareMode, nil, syscall.OPEN_ALWAYS, syscall.FILE_ATTRIBUTE_NORMAL, 0)
+	}
+	if err != nil {
+		return
+	}
+	fl = &windowsFileLock{fd: fd}
+	return
+}
+
+func moveFileEx(from *uint16, to *uint16, flags uint32) error {
+	r1, _, e1 := syscall.Syscall(procMoveFileExW.Addr(), 3, uintptr(unsafe.Pointer(from)), uintptr(unsafe.Pointer(to)), uintptr(flags))
+	if r1 == 0 {
+		if e1 != 0 {
+			return error(e1)
+		}
+		return syscall.EINVAL
+	}
+	return nil
+}
+
+func rename(oldpath, newpath string) error {
+	from, err := syscall.UTF16PtrFromString(oldpath)
+	if err != nil {
+		return err
+	}
+	to, err := syscall.UTF16PtrFromString(newpath)
+	if err != nil {
+		return err
+	}
+	return moveFileEx(from, to, _MOVEFILE_REPLACE_EXISTING)
+}
+
+func syncDir(name string) error { return nil }
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go
new file mode 100644
index 0000000000..838f1bee1b
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/mem_storage.go
@@ -0,0 +1,222 @@
+// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package storage
+
+import (
+	"bytes"
+	"os"
+	"sync"
+)
+
+const typeShift = 4
+
+// Verify at compile-time that typeShift is large enough to cover all FileType
+// values by confirming that 0 == 0.
+var _ [0]struct{} = [TypeAll >> typeShift]struct{}{}
+
+type memStorageLock struct {
+	ms *memStorage
+}
+
+func (lock *memStorageLock) Unlock() {
+	ms := lock.ms
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	if ms.slock == lock {
+		ms.slock = nil
+	}
+	return
+}
+
+// memStorage is a memory-backed storage.
+type memStorage struct {
+	mu    sync.Mutex
+	slock *memStorageLock
+	files map[uint64]*memFile
+	meta  FileDesc
+}
+
+// NewMemStorage returns a new memory-backed storage implementation.
+func NewMemStorage() Storage {
+	return &memStorage{
+		files: make(map[uint64]*memFile),
+	}
+}
+
+func (ms *memStorage) Lock() (Locker, error) {
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	if ms.slock != nil {
+		return nil, ErrLocked
+	}
+	ms.slock = &memStorageLock{ms: ms}
+	return ms.slock, nil
+}
+
+func (*memStorage) Log(str string) {}
+
+func (ms *memStorage) SetMeta(fd FileDesc) error {
+	if !FileDescOk(fd) {
+		return ErrInvalidFile
+	}
+
+	ms.mu.Lock()
+	ms.meta = fd
+	ms.mu.Unlock()
+	return nil
+}
+
+func (ms *memStorage) GetMeta() (FileDesc, error) {
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	if ms.meta.Zero() {
+		return FileDesc{}, os.ErrNotExist
+	}
+	return ms.meta, nil
+}
+
+func (ms *memStorage) List(ft FileType) ([]FileDesc, error) {
+	ms.mu.Lock()
+	var fds []FileDesc
+	for x := range ms.files {
+		fd := unpackFile(x)
+		if fd.Type&ft != 0 {
+			fds = append(fds, fd)
+		}
+	}
+	ms.mu.Unlock()
+	return fds, nil
+}
+
+func (ms *memStorage) Open(fd FileDesc) (Reader, error) {
+	if !FileDescOk(fd) {
+		return nil, ErrInvalidFile
+	}
+
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	if m, exist := ms.files[packFile(fd)]; exist {
+		if m.open {
+			return nil, errFileOpen
+		}
+		m.open = true
+		return &memReader{Reader: bytes.NewReader(m.Bytes()), ms: ms, m: m}, nil
+	}
+	return nil, os.ErrNotExist
+}
+
+func (ms *memStorage) Create(fd FileDesc) (Writer, error) {
+	if !FileDescOk(fd) {
+		return nil, ErrInvalidFile
+	}
+
+	x := packFile(fd)
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	m, exist := ms.files[x]
+	if exist {
+		if m.open {
+			return nil, errFileOpen
+		}
+		m.Reset()
+	} else {
+		m = &memFile{}
+		ms.files[x] = m
+	}
+	m.open = true
+	return &memWriter{memFile: m, ms: ms}, nil
+}
+
+func (ms *memStorage) Remove(fd FileDesc) error {
+	if !FileDescOk(fd) {
+		return ErrInvalidFile
+	}
+
+	x := packFile(fd)
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	if _, exist := ms.files[x]; exist {
+		delete(ms.files, x)
+		return nil
+	}
+	return os.ErrNotExist
+}
+
+func (ms *memStorage) Rename(oldfd, newfd FileDesc) error {
+	if !FileDescOk(oldfd) || !FileDescOk(newfd) {
+		return ErrInvalidFile
+	}
+	if oldfd == newfd {
+		return nil
+	}
+
+	oldx := packFile(oldfd)
+	newx := packFile(newfd)
+	ms.mu.Lock()
+	defer ms.mu.Unlock()
+	oldm, exist := ms.files[oldx]
+	if !exist {
+		return os.ErrNotExist
+	}
+	newm, exist := ms.files[newx]
+	if (exist && newm.open) || oldm.open {
+		return errFileOpen
+	}
+	delete(ms.files, oldx)
+	ms.files[newx] = oldm
+	return nil
+}
+
+func (*memStorage) Close() error { return nil }
+
+type memFile struct {
+	bytes.Buffer
+	open bool
+}
+
+type memReader struct {
+	*bytes.Reader
+	ms     *memStorage
+	m      *memFile
+	closed bool
+}
+
+func (mr *memReader) Close() error {
+	mr.ms.mu.Lock()
+	defer mr.ms.mu.Unlock()
+	if mr.closed {
+		return ErrClosed
+	}
+	mr.m.open = false
+	return nil
+}
+
+type memWriter struct {
+	*memFile
+	ms     *memStorage
+	closed bool
+}
+
+func (*memWriter) Sync() error { return nil }
+
+func (mw *memWriter) Close() error {
+	mw.ms.mu.Lock()
+	defer mw.ms.mu.Unlock()
+	if mw.closed {
+		return ErrClosed
+	}
+	mw.memFile.open = false
+	return nil
+}
+
+func packFile(fd FileDesc) uint64 {
+	return uint64(fd.Num)<<typeShift | uint64(fd.Type)
+}
+
+func unpackFile(x uint64) FileDesc {
+	return FileDesc{FileType(x) & TypeAll, int64(x >> typeShift)}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/storage/storage.go b/vendor/github.com/syndtr/goleveldb/leveldb/storage/storage.go
new file mode 100644
index 0000000000..4e4a724258
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/storage/storage.go
@@ -0,0 +1,187 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package storage provides storage abstraction for LevelDB.
+package storage
+
+import (
+	"errors"
+	"fmt"
+	"io"
+)
+
+// FileType represent a file type.
+type FileType int
+
+// File types.
+const (
+	TypeManifest FileType = 1 << iota
+	TypeJournal
+	TypeTable
+	TypeTemp
+
+	TypeAll = TypeManifest | TypeJournal | TypeTable | TypeTemp
+)
+
+func (t FileType) String() string {
+	switch t {
+	case TypeManifest:
+		return "manifest"
+	case TypeJournal:
+		return "journal"
+	case TypeTable:
+		return "table"
+	case TypeTemp:
+		return "temp"
+	}
+	return fmt.Sprintf("<unknown:%d>", t)
+}
+
+// Common error.
+var (
+	ErrInvalidFile = errors.New("leveldb/storage: invalid file for argument")
+	ErrLocked      = errors.New("leveldb/storage: already locked")
+	ErrClosed      = errors.New("leveldb/storage: closed")
+)
+
+// ErrCorrupted is the type that wraps errors that indicate corruption of
+// a file. Package storage has its own type instead of using
+// errors.ErrCorrupted to prevent circular import.
+type ErrCorrupted struct {
+	Fd  FileDesc
+	Err error
+}
+
+func isCorrupted(err error) bool {
+	switch err.(type) {
+	case *ErrCorrupted:
+		return true
+	}
+	return false
+}
+
+func (e *ErrCorrupted) Error() string {
+	if !e.Fd.Zero() {
+		return fmt.Sprintf("%v [file=%v]", e.Err, e.Fd)
+	}
+	return e.Err.Error()
+}
+
+// Syncer is the interface that wraps basic Sync method.
+type Syncer interface {
+	// Sync commits the current contents of the file to stable storage.
+	Sync() error
+}
+
+// Reader is the interface that groups the basic Read, Seek, ReadAt and Close
+// methods.
+type Reader interface {
+	io.ReadSeeker
+	io.ReaderAt
+	io.Closer
+}
+
+// Writer is the interface that groups the basic Write, Sync and Close
+// methods.
+type Writer interface {
+	io.WriteCloser
+	Syncer
+}
+
+// Locker is the interface that wraps Unlock method.
+type Locker interface {
+	Unlock()
+}
+
+// FileDesc is a 'file descriptor'.
+type FileDesc struct {
+	Type FileType
+	Num  int64
+}
+
+func (fd FileDesc) String() string {
+	switch fd.Type {
+	case TypeManifest:
+		return fmt.Sprintf("MANIFEST-%06d", fd.Num)
+	case TypeJournal:
+		return fmt.Sprintf("%06d.log", fd.Num)
+	case TypeTable:
+		return fmt.Sprintf("%06d.ldb", fd.Num)
+	case TypeTemp:
+		return fmt.Sprintf("%06d.tmp", fd.Num)
+	default:
+		return fmt.Sprintf("%#x-%d", fd.Type, fd.Num)
+	}
+}
+
+// Zero returns true if fd == (FileDesc{}).
+func (fd FileDesc) Zero() bool {
+	return fd == (FileDesc{})
+}
+
+// FileDescOk returns true if fd is a valid 'file descriptor'.
+func FileDescOk(fd FileDesc) bool {
+	switch fd.Type {
+	case TypeManifest:
+	case TypeJournal:
+	case TypeTable:
+	case TypeTemp:
+	default:
+		return false
+	}
+	return fd.Num >= 0
+}
+
+// Storage is the storage. A storage instance must be safe for concurrent use.
+type Storage interface {
+	// Lock locks the storage. Any subsequent attempt to call Lock will fail
+	// until the last lock released.
+	// Caller should call Unlock method after use.
+	Lock() (Locker, error)
+
+	// Log logs a string. This is used for logging.
+	// An implementation may write to a file, stdout or simply do nothing.
+	Log(str string)
+
+	// SetMeta store 'file descriptor' that can later be acquired using GetMeta
+	// method. The 'file descriptor' should point to a valid file.
+	// SetMeta should be implemented in such way that changes should happen
+	// atomically.
+	SetMeta(fd FileDesc) error
+
+	// GetMeta returns 'file descriptor' stored in meta. The 'file descriptor'
+	// can be updated using SetMeta method.
+	// Returns os.ErrNotExist if meta doesn't store any 'file descriptor', or
+	// 'file descriptor' point to nonexistent file.
+	GetMeta() (FileDesc, error)
+
+	// List returns file descriptors that match the given file types.
+	// The file types may be OR'ed together.
+	List(ft FileType) ([]FileDesc, error)
+
+	// Open opens file with the given 'file descriptor' read-only.
+	// Returns os.ErrNotExist error if the file does not exist.
+	// Returns ErrClosed if the underlying storage is closed.
+	Open(fd FileDesc) (Reader, error)
+
+	// Create creates file with the given 'file descriptor', truncate if already
+	// exist and opens write-only.
+	// Returns ErrClosed if the underlying storage is closed.
+	Create(fd FileDesc) (Writer, error)
+
+	// Remove removes file with the given 'file descriptor'.
+	// Returns ErrClosed if the underlying storage is closed.
+	Remove(fd FileDesc) error
+
+	// Rename renames file from oldfd to newfd.
+	// Returns ErrClosed if the underlying storage is closed.
+	Rename(oldfd, newfd FileDesc) error
+
+	// Close closes the storage.
+	// It is valid to call Close multiple times. Other methods should not be
+	// called after the storage has been closed.
+	Close() error
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/table.go b/vendor/github.com/syndtr/goleveldb/leveldb/table.go
new file mode 100644
index 0000000000..1fac60d050
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/table.go
@@ -0,0 +1,531 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"fmt"
+	"sort"
+	"sync/atomic"
+
+	"github.com/syndtr/goleveldb/leveldb/cache"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"github.com/syndtr/goleveldb/leveldb/table"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// tFile holds basic information about a table.
+type tFile struct {
+	fd         storage.FileDesc
+	seekLeft   int32
+	size       int64
+	imin, imax internalKey
+}
+
+// Returns true if given key is after largest key of this table.
+func (t *tFile) after(icmp *iComparer, ukey []byte) bool {
+	return ukey != nil && icmp.uCompare(ukey, t.imax.ukey()) > 0
+}
+
+// Returns true if given key is before smallest key of this table.
+func (t *tFile) before(icmp *iComparer, ukey []byte) bool {
+	return ukey != nil && icmp.uCompare(ukey, t.imin.ukey()) < 0
+}
+
+// Returns true if given key range overlaps with this table key range.
+func (t *tFile) overlaps(icmp *iComparer, umin, umax []byte) bool {
+	return !t.after(icmp, umin) && !t.before(icmp, umax)
+}
+
+// Cosumes one seek and return current seeks left.
+func (t *tFile) consumeSeek() int32 {
+	return atomic.AddInt32(&t.seekLeft, -1)
+}
+
+// Creates new tFile.
+func newTableFile(fd storage.FileDesc, size int64, imin, imax internalKey) *tFile {
+	f := &tFile{
+		fd:   fd,
+		size: size,
+		imin: imin,
+		imax: imax,
+	}
+
+	// We arrange to automatically compact this file after
+	// a certain number of seeks.  Let's assume:
+	//   (1) One seek costs 10ms
+	//   (2) Writing or reading 1MB costs 10ms (100MB/s)
+	//   (3) A compaction of 1MB does 25MB of IO:
+	//         1MB read from this level
+	//         10-12MB read from next level (boundaries may be misaligned)
+	//         10-12MB written to next level
+	// This implies that 25 seeks cost the same as the compaction
+	// of 1MB of data.  I.e., one seek costs approximately the
+	// same as the compaction of 40KB of data.  We are a little
+	// conservative and allow approximately one seek for every 16KB
+	// of data before triggering a compaction.
+	f.seekLeft = int32(size / 16384)
+	if f.seekLeft < 100 {
+		f.seekLeft = 100
+	}
+
+	return f
+}
+
+func tableFileFromRecord(r atRecord) *tFile {
+	return newTableFile(storage.FileDesc{Type: storage.TypeTable, Num: r.num}, r.size, r.imin, r.imax)
+}
+
+// tFiles hold multiple tFile.
+type tFiles []*tFile
+
+func (tf tFiles) Len() int      { return len(tf) }
+func (tf tFiles) Swap(i, j int) { tf[i], tf[j] = tf[j], tf[i] }
+
+func (tf tFiles) nums() string {
+	x := "[ "
+	for i, f := range tf {
+		if i != 0 {
+			x += ", "
+		}
+		x += fmt.Sprint(f.fd.Num)
+	}
+	x += " ]"
+	return x
+}
+
+// Returns true if i smallest key is less than j.
+// This used for sort by key in ascending order.
+func (tf tFiles) lessByKey(icmp *iComparer, i, j int) bool {
+	a, b := tf[i], tf[j]
+	n := icmp.Compare(a.imin, b.imin)
+	if n == 0 {
+		return a.fd.Num < b.fd.Num
+	}
+	return n < 0
+}
+
+// Returns true if i file number is greater than j.
+// This used for sort by file number in descending order.
+func (tf tFiles) lessByNum(i, j int) bool {
+	return tf[i].fd.Num > tf[j].fd.Num
+}
+
+// Sorts tables by key in ascending order.
+func (tf tFiles) sortByKey(icmp *iComparer) {
+	sort.Sort(&tFilesSortByKey{tFiles: tf, icmp: icmp})
+}
+
+// Sorts tables by file number in descending order.
+func (tf tFiles) sortByNum() {
+	sort.Sort(&tFilesSortByNum{tFiles: tf})
+}
+
+// Returns sum of all tables size.
+func (tf tFiles) size() (sum int64) {
+	for _, t := range tf {
+		sum += t.size
+	}
+	return sum
+}
+
+// Searches smallest index of tables whose its smallest
+// key is after or equal with given key.
+func (tf tFiles) searchMin(icmp *iComparer, ikey internalKey) int {
+	return sort.Search(len(tf), func(i int) bool {
+		return icmp.Compare(tf[i].imin, ikey) >= 0
+	})
+}
+
+// Searches smallest index of tables whose its largest
+// key is after or equal with given key.
+func (tf tFiles) searchMax(icmp *iComparer, ikey internalKey) int {
+	return sort.Search(len(tf), func(i int) bool {
+		return icmp.Compare(tf[i].imax, ikey) >= 0
+	})
+}
+
+// Returns true if given key range overlaps with one or more
+// tables key range. If unsorted is true then binary search will not be used.
+func (tf tFiles) overlaps(icmp *iComparer, umin, umax []byte, unsorted bool) bool {
+	if unsorted {
+		// Check against all files.
+		for _, t := range tf {
+			if t.overlaps(icmp, umin, umax) {
+				return true
+			}
+		}
+		return false
+	}
+
+	i := 0
+	if len(umin) > 0 {
+		// Find the earliest possible internal key for min.
+		i = tf.searchMax(icmp, makeInternalKey(nil, umin, keyMaxSeq, keyTypeSeek))
+	}
+	if i >= len(tf) {
+		// Beginning of range is after all files, so no overlap.
+		return false
+	}
+	return !tf[i].before(icmp, umax)
+}
+
+// Returns tables whose its key range overlaps with given key range.
+// Range will be expanded if ukey found hop across tables.
+// If overlapped is true then the search will be restarted if umax
+// expanded.
+// The dst content will be overwritten.
+func (tf tFiles) getOverlaps(dst tFiles, icmp *iComparer, umin, umax []byte, overlapped bool) tFiles {
+	dst = dst[:0]
+	for i := 0; i < len(tf); {
+		t := tf[i]
+		if t.overlaps(icmp, umin, umax) {
+			if umin != nil && icmp.uCompare(t.imin.ukey(), umin) < 0 {
+				umin = t.imin.ukey()
+				dst = dst[:0]
+				i = 0
+				continue
+			} else if umax != nil && icmp.uCompare(t.imax.ukey(), umax) > 0 {
+				umax = t.imax.ukey()
+				// Restart search if it is overlapped.
+				if overlapped {
+					dst = dst[:0]
+					i = 0
+					continue
+				}
+			}
+
+			dst = append(dst, t)
+		}
+		i++
+	}
+
+	return dst
+}
+
+// Returns tables key range.
+func (tf tFiles) getRange(icmp *iComparer) (imin, imax internalKey) {
+	for i, t := range tf {
+		if i == 0 {
+			imin, imax = t.imin, t.imax
+			continue
+		}
+		if icmp.Compare(t.imin, imin) < 0 {
+			imin = t.imin
+		}
+		if icmp.Compare(t.imax, imax) > 0 {
+			imax = t.imax
+		}
+	}
+
+	return
+}
+
+// Creates iterator index from tables.
+func (tf tFiles) newIndexIterator(tops *tOps, icmp *iComparer, slice *util.Range, ro *opt.ReadOptions) iterator.IteratorIndexer {
+	if slice != nil {
+		var start, limit int
+		if slice.Start != nil {
+			start = tf.searchMax(icmp, internalKey(slice.Start))
+		}
+		if slice.Limit != nil {
+			limit = tf.searchMin(icmp, internalKey(slice.Limit))
+		} else {
+			limit = tf.Len()
+		}
+		tf = tf[start:limit]
+	}
+	return iterator.NewArrayIndexer(&tFilesArrayIndexer{
+		tFiles: tf,
+		tops:   tops,
+		icmp:   icmp,
+		slice:  slice,
+		ro:     ro,
+	})
+}
+
+// Tables iterator index.
+type tFilesArrayIndexer struct {
+	tFiles
+	tops  *tOps
+	icmp  *iComparer
+	slice *util.Range
+	ro    *opt.ReadOptions
+}
+
+func (a *tFilesArrayIndexer) Search(key []byte) int {
+	return a.searchMax(a.icmp, internalKey(key))
+}
+
+func (a *tFilesArrayIndexer) Get(i int) iterator.Iterator {
+	if i == 0 || i == a.Len()-1 {
+		return a.tops.newIterator(a.tFiles[i], a.slice, a.ro)
+	}
+	return a.tops.newIterator(a.tFiles[i], nil, a.ro)
+}
+
+// Helper type for sortByKey.
+type tFilesSortByKey struct {
+	tFiles
+	icmp *iComparer
+}
+
+func (x *tFilesSortByKey) Less(i, j int) bool {
+	return x.lessByKey(x.icmp, i, j)
+}
+
+// Helper type for sortByNum.
+type tFilesSortByNum struct {
+	tFiles
+}
+
+func (x *tFilesSortByNum) Less(i, j int) bool {
+	return x.lessByNum(i, j)
+}
+
+// Table operations.
+type tOps struct {
+	s            *session
+	noSync       bool
+	evictRemoved bool
+	cache        *cache.Cache
+	bcache       *cache.Cache
+	bpool        *util.BufferPool
+}
+
+// Creates an empty table and returns table writer.
+func (t *tOps) create() (*tWriter, error) {
+	fd := storage.FileDesc{Type: storage.TypeTable, Num: t.s.allocFileNum()}
+	fw, err := t.s.stor.Create(fd)
+	if err != nil {
+		return nil, err
+	}
+	return &tWriter{
+		t:  t,
+		fd: fd,
+		w:  fw,
+		tw: table.NewWriter(fw, t.s.o.Options),
+	}, nil
+}
+
+// Builds table from src iterator.
+func (t *tOps) createFrom(src iterator.Iterator) (f *tFile, n int, err error) {
+	w, err := t.create()
+	if err != nil {
+		return
+	}
+
+	defer func() {
+		if err != nil {
+			w.drop()
+		}
+	}()
+
+	for src.Next() {
+		err = w.append(src.Key(), src.Value())
+		if err != nil {
+			return
+		}
+	}
+	err = src.Error()
+	if err != nil {
+		return
+	}
+
+	n = w.tw.EntriesLen()
+	f, err = w.finish()
+	return
+}
+
+// Opens table. It returns a cache handle, which should
+// be released after use.
+func (t *tOps) open(f *tFile) (ch *cache.Handle, err error) {
+	ch = t.cache.Get(0, uint64(f.fd.Num), func() (size int, value cache.Value) {
+		var r storage.Reader
+		r, err = t.s.stor.Open(f.fd)
+		if err != nil {
+			return 0, nil
+		}
+
+		var bcache *cache.NamespaceGetter
+		if t.bcache != nil {
+			bcache = &cache.NamespaceGetter{Cache: t.bcache, NS: uint64(f.fd.Num)}
+		}
+
+		var tr *table.Reader
+		tr, err = table.NewReader(r, f.size, f.fd, bcache, t.bpool, t.s.o.Options)
+		if err != nil {
+			r.Close()
+			return 0, nil
+		}
+		return 1, tr
+
+	})
+	if ch == nil && err == nil {
+		err = ErrClosed
+	}
+	return
+}
+
+// Finds key/value pair whose key is greater than or equal to the
+// given key.
+func (t *tOps) find(f *tFile, key []byte, ro *opt.ReadOptions) (rkey, rvalue []byte, err error) {
+	ch, err := t.open(f)
+	if err != nil {
+		return nil, nil, err
+	}
+	defer ch.Release()
+	return ch.Value().(*table.Reader).Find(key, true, ro)
+}
+
+// Finds key that is greater than or equal to the given key.
+func (t *tOps) findKey(f *tFile, key []byte, ro *opt.ReadOptions) (rkey []byte, err error) {
+	ch, err := t.open(f)
+	if err != nil {
+		return nil, err
+	}
+	defer ch.Release()
+	return ch.Value().(*table.Reader).FindKey(key, true, ro)
+}
+
+// Returns approximate offset of the given key.
+func (t *tOps) offsetOf(f *tFile, key []byte) (offset int64, err error) {
+	ch, err := t.open(f)
+	if err != nil {
+		return
+	}
+	defer ch.Release()
+	return ch.Value().(*table.Reader).OffsetOf(key)
+}
+
+// Creates an iterator from the given table.
+func (t *tOps) newIterator(f *tFile, slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+	ch, err := t.open(f)
+	if err != nil {
+		return iterator.NewEmptyIterator(err)
+	}
+	iter := ch.Value().(*table.Reader).NewIterator(slice, ro)
+	iter.SetReleaser(ch)
+	return iter
+}
+
+// Removes table from persistent storage. It waits until
+// no one use the the table.
+func (t *tOps) remove(f *tFile) {
+	t.cache.Delete(0, uint64(f.fd.Num), func() {
+		if err := t.s.stor.Remove(f.fd); err != nil {
+			t.s.logf("table@remove removing @%d %q", f.fd.Num, err)
+		} else {
+			t.s.logf("table@remove removed @%d", f.fd.Num)
+		}
+		if t.evictRemoved && t.bcache != nil {
+			t.bcache.EvictNS(uint64(f.fd.Num))
+		}
+	})
+}
+
+// Closes the table ops instance. It will close all tables,
+// regadless still used or not.
+func (t *tOps) close() {
+	t.bpool.Close()
+	t.cache.Close()
+	if t.bcache != nil {
+		t.bcache.CloseWeak()
+	}
+}
+
+// Creates new initialized table ops instance.
+func newTableOps(s *session) *tOps {
+	var (
+		cacher cache.Cacher
+		bcache *cache.Cache
+		bpool  *util.BufferPool
+	)
+	if s.o.GetOpenFilesCacheCapacity() > 0 {
+		cacher = cache.NewLRU(s.o.GetOpenFilesCacheCapacity())
+	}
+	if !s.o.GetDisableBlockCache() {
+		var bcacher cache.Cacher
+		if s.o.GetBlockCacheCapacity() > 0 {
+			bcacher = s.o.GetBlockCacher().New(s.o.GetBlockCacheCapacity())
+		}
+		bcache = cache.NewCache(bcacher)
+	}
+	if !s.o.GetDisableBufferPool() {
+		bpool = util.NewBufferPool(s.o.GetBlockSize() + 5)
+	}
+	return &tOps{
+		s:            s,
+		noSync:       s.o.GetNoSync(),
+		evictRemoved: s.o.GetBlockCacheEvictRemoved(),
+		cache:        cache.NewCache(cacher),
+		bcache:       bcache,
+		bpool:        bpool,
+	}
+}
+
+// tWriter wraps the table writer. It keep track of file descriptor
+// and added key range.
+type tWriter struct {
+	t *tOps
+
+	fd storage.FileDesc
+	w  storage.Writer
+	tw *table.Writer
+
+	first, last []byte
+}
+
+// Append key/value pair to the table.
+func (w *tWriter) append(key, value []byte) error {
+	if w.first == nil {
+		w.first = append([]byte{}, key...)
+	}
+	w.last = append(w.last[:0], key...)
+	return w.tw.Append(key, value)
+}
+
+// Returns true if the table is empty.
+func (w *tWriter) empty() bool {
+	return w.first == nil
+}
+
+// Closes the storage.Writer.
+func (w *tWriter) close() {
+	if w.w != nil {
+		w.w.Close()
+		w.w = nil
+	}
+}
+
+// Finalizes the table and returns table file.
+func (w *tWriter) finish() (f *tFile, err error) {
+	defer w.close()
+	err = w.tw.Close()
+	if err != nil {
+		return
+	}
+	if !w.t.noSync {
+		err = w.w.Sync()
+		if err != nil {
+			return
+		}
+	}
+	f = newTableFile(w.fd, int64(w.tw.BytesLen()), internalKey(w.first), internalKey(w.last))
+	return
+}
+
+// Drops the table.
+func (w *tWriter) drop() {
+	w.close()
+	w.t.s.stor.Remove(w.fd)
+	w.t.s.reuseFileNum(w.fd.Num)
+	w.tw = nil
+	w.first = nil
+	w.last = nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/table/reader.go b/vendor/github.com/syndtr/goleveldb/leveldb/table/reader.go
new file mode 100644
index 0000000000..16cfbaa006
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/table/reader.go
@@ -0,0 +1,1135 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package table
+
+import (
+	"encoding/binary"
+	"fmt"
+	"io"
+	"sort"
+	"strings"
+	"sync"
+
+	"github.com/golang/snappy"
+
+	"github.com/syndtr/goleveldb/leveldb/cache"
+	"github.com/syndtr/goleveldb/leveldb/comparer"
+	"github.com/syndtr/goleveldb/leveldb/errors"
+	"github.com/syndtr/goleveldb/leveldb/filter"
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+// Reader errors.
+var (
+	ErrNotFound       = errors.ErrNotFound
+	ErrReaderReleased = errors.New("leveldb/table: reader released")
+	ErrIterReleased   = errors.New("leveldb/table: iterator released")
+)
+
+// ErrCorrupted describes error due to corruption. This error will be wrapped
+// with errors.ErrCorrupted.
+type ErrCorrupted struct {
+	Pos    int64
+	Size   int64
+	Kind   string
+	Reason string
+}
+
+func (e *ErrCorrupted) Error() string {
+	return fmt.Sprintf("leveldb/table: corruption on %s (pos=%d): %s", e.Kind, e.Pos, e.Reason)
+}
+
+func max(x, y int) int {
+	if x > y {
+		return x
+	}
+	return y
+}
+
+type block struct {
+	bpool          *util.BufferPool
+	bh             blockHandle
+	data           []byte
+	restartsLen    int
+	restartsOffset int
+}
+
+func (b *block) seek(cmp comparer.Comparer, rstart, rlimit int, key []byte) (index, offset int, err error) {
+	index = sort.Search(b.restartsLen-rstart-(b.restartsLen-rlimit), func(i int) bool {
+		offset := int(binary.LittleEndian.Uint32(b.data[b.restartsOffset+4*(rstart+i):]))
+		offset++                                    // shared always zero, since this is a restart point
+		v1, n1 := binary.Uvarint(b.data[offset:])   // key length
+		_, n2 := binary.Uvarint(b.data[offset+n1:]) // value length
+		m := offset + n1 + n2
+		return cmp.Compare(b.data[m:m+int(v1)], key) > 0
+	}) + rstart - 1
+	if index < rstart {
+		// The smallest key is greater-than key sought.
+		index = rstart
+	}
+	offset = int(binary.LittleEndian.Uint32(b.data[b.restartsOffset+4*index:]))
+	return
+}
+
+func (b *block) restartIndex(rstart, rlimit, offset int) int {
+	return sort.Search(b.restartsLen-rstart-(b.restartsLen-rlimit), func(i int) bool {
+		return int(binary.LittleEndian.Uint32(b.data[b.restartsOffset+4*(rstart+i):])) > offset
+	}) + rstart - 1
+}
+
+func (b *block) restartOffset(index int) int {
+	return int(binary.LittleEndian.Uint32(b.data[b.restartsOffset+4*index:]))
+}
+
+func (b *block) entry(offset int) (key, value []byte, nShared, n int, err error) {
+	if offset >= b.restartsOffset {
+		if offset != b.restartsOffset {
+			err = &ErrCorrupted{Reason: "entries offset not aligned"}
+		}
+		return
+	}
+	v0, n0 := binary.Uvarint(b.data[offset:])       // Shared prefix length
+	v1, n1 := binary.Uvarint(b.data[offset+n0:])    // Key length
+	v2, n2 := binary.Uvarint(b.data[offset+n0+n1:]) // Value length
+	m := n0 + n1 + n2
+	n = m + int(v1) + int(v2)
+	if n0 <= 0 || n1 <= 0 || n2 <= 0 || offset+n > b.restartsOffset {
+		err = &ErrCorrupted{Reason: "entries corrupted"}
+		return
+	}
+	key = b.data[offset+m : offset+m+int(v1)]
+	value = b.data[offset+m+int(v1) : offset+n]
+	nShared = int(v0)
+	return
+}
+
+func (b *block) Release() {
+	b.bpool.Put(b.data)
+	b.bpool = nil
+	b.data = nil
+}
+
+type dir int
+
+const (
+	dirReleased dir = iota - 1
+	dirSOI
+	dirEOI
+	dirBackward
+	dirForward
+)
+
+type blockIter struct {
+	tr            *Reader
+	block         *block
+	blockReleaser util.Releaser
+	releaser      util.Releaser
+	key, value    []byte
+	offset        int
+	// Previous offset, only filled by Next.
+	prevOffset   int
+	prevNode     []int
+	prevKeys     []byte
+	restartIndex int
+	// Iterator direction.
+	dir dir
+	// Restart index slice range.
+	riStart int
+	riLimit int
+	// Offset slice range.
+	offsetStart     int
+	offsetRealStart int
+	offsetLimit     int
+	// Error.
+	err error
+}
+
+func (i *blockIter) sErr(err error) {
+	i.err = err
+	i.key = nil
+	i.value = nil
+	i.prevNode = nil
+	i.prevKeys = nil
+}
+
+func (i *blockIter) reset() {
+	if i.dir == dirBackward {
+		i.prevNode = i.prevNode[:0]
+		i.prevKeys = i.prevKeys[:0]
+	}
+	i.restartIndex = i.riStart
+	i.offset = i.offsetStart
+	i.dir = dirSOI
+	i.key = i.key[:0]
+	i.value = nil
+}
+
+func (i *blockIter) isFirst() bool {
+	switch i.dir {
+	case dirForward:
+		return i.prevOffset == i.offsetRealStart
+	case dirBackward:
+		return len(i.prevNode) == 1 && i.restartIndex == i.riStart
+	}
+	return false
+}
+
+func (i *blockIter) isLast() bool {
+	switch i.dir {
+	case dirForward, dirBackward:
+		return i.offset == i.offsetLimit
+	}
+	return false
+}
+
+func (i *blockIter) First() bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.dir == dirBackward {
+		i.prevNode = i.prevNode[:0]
+		i.prevKeys = i.prevKeys[:0]
+	}
+	i.dir = dirSOI
+	return i.Next()
+}
+
+func (i *blockIter) Last() bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.dir == dirBackward {
+		i.prevNode = i.prevNode[:0]
+		i.prevKeys = i.prevKeys[:0]
+	}
+	i.dir = dirEOI
+	return i.Prev()
+}
+
+func (i *blockIter) Seek(key []byte) bool {
+	if i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	ri, offset, err := i.block.seek(i.tr.cmp, i.riStart, i.riLimit, key)
+	if err != nil {
+		i.sErr(err)
+		return false
+	}
+	i.restartIndex = ri
+	i.offset = max(i.offsetStart, offset)
+	if i.dir == dirSOI || i.dir == dirEOI {
+		i.dir = dirForward
+	}
+	for i.Next() {
+		if i.tr.cmp.Compare(i.key, key) >= 0 {
+			return true
+		}
+	}
+	return false
+}
+
+func (i *blockIter) Next() bool {
+	if i.dir == dirEOI || i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	if i.dir == dirSOI {
+		i.restartIndex = i.riStart
+		i.offset = i.offsetStart
+	} else if i.dir == dirBackward {
+		i.prevNode = i.prevNode[:0]
+		i.prevKeys = i.prevKeys[:0]
+	}
+	for i.offset < i.offsetRealStart {
+		key, value, nShared, n, err := i.block.entry(i.offset)
+		if err != nil {
+			i.sErr(i.tr.fixErrCorruptedBH(i.block.bh, err))
+			return false
+		}
+		if n == 0 {
+			i.dir = dirEOI
+			return false
+		}
+		i.key = append(i.key[:nShared], key...)
+		i.value = value
+		i.offset += n
+	}
+	if i.offset >= i.offsetLimit {
+		i.dir = dirEOI
+		if i.offset != i.offsetLimit {
+			i.sErr(i.tr.newErrCorruptedBH(i.block.bh, "entries offset not aligned"))
+		}
+		return false
+	}
+	key, value, nShared, n, err := i.block.entry(i.offset)
+	if err != nil {
+		i.sErr(i.tr.fixErrCorruptedBH(i.block.bh, err))
+		return false
+	}
+	if n == 0 {
+		i.dir = dirEOI
+		return false
+	}
+	i.key = append(i.key[:nShared], key...)
+	i.value = value
+	i.prevOffset = i.offset
+	i.offset += n
+	i.dir = dirForward
+	return true
+}
+
+func (i *blockIter) Prev() bool {
+	if i.dir == dirSOI || i.err != nil {
+		return false
+	} else if i.dir == dirReleased {
+		i.err = ErrIterReleased
+		return false
+	}
+
+	var ri int
+	if i.dir == dirForward {
+		// Change direction.
+		i.offset = i.prevOffset
+		if i.offset == i.offsetRealStart {
+			i.dir = dirSOI
+			return false
+		}
+		ri = i.block.restartIndex(i.restartIndex, i.riLimit, i.offset)
+		i.dir = dirBackward
+	} else if i.dir == dirEOI {
+		// At the end of iterator.
+		i.restartIndex = i.riLimit
+		i.offset = i.offsetLimit
+		if i.offset == i.offsetRealStart {
+			i.dir = dirSOI
+			return false
+		}
+		ri = i.riLimit - 1
+		i.dir = dirBackward
+	} else if len(i.prevNode) == 1 {
+		// This is the end of a restart range.
+		i.offset = i.prevNode[0]
+		i.prevNode = i.prevNode[:0]
+		if i.restartIndex == i.riStart {
+			i.dir = dirSOI
+			return false
+		}
+		i.restartIndex--
+		ri = i.restartIndex
+	} else {
+		// In the middle of restart range, get from cache.
+		n := len(i.prevNode) - 3
+		node := i.prevNode[n:]
+		i.prevNode = i.prevNode[:n]
+		// Get the key.
+		ko := node[0]
+		i.key = append(i.key[:0], i.prevKeys[ko:]...)
+		i.prevKeys = i.prevKeys[:ko]
+		// Get the value.
+		vo := node[1]
+		vl := vo + node[2]
+		i.value = i.block.data[vo:vl]
+		i.offset = vl
+		return true
+	}
+	// Build entries cache.
+	i.key = i.key[:0]
+	i.value = nil
+	offset := i.block.restartOffset(ri)
+	if offset == i.offset {
+		ri--
+		if ri < 0 {
+			i.dir = dirSOI
+			return false
+		}
+		offset = i.block.restartOffset(ri)
+	}
+	i.prevNode = append(i.prevNode, offset)
+	for {
+		key, value, nShared, n, err := i.block.entry(offset)
+		if err != nil {
+			i.sErr(i.tr.fixErrCorruptedBH(i.block.bh, err))
+			return false
+		}
+		if offset >= i.offsetRealStart {
+			if i.value != nil {
+				// Appends 3 variables:
+				// 1. Previous keys offset
+				// 2. Value offset in the data block
+				// 3. Value length
+				i.prevNode = append(i.prevNode, len(i.prevKeys), offset-len(i.value), len(i.value))
+				i.prevKeys = append(i.prevKeys, i.key...)
+			}
+			i.value = value
+		}
+		i.key = append(i.key[:nShared], key...)
+		offset += n
+		// Stop if target offset reached.
+		if offset >= i.offset {
+			if offset != i.offset {
+				i.sErr(i.tr.newErrCorruptedBH(i.block.bh, "entries offset not aligned"))
+				return false
+			}
+
+			break
+		}
+	}
+	i.restartIndex = ri
+	i.offset = offset
+	return true
+}
+
+func (i *blockIter) Key() []byte {
+	if i.err != nil || i.dir <= dirEOI {
+		return nil
+	}
+	return i.key
+}
+
+func (i *blockIter) Value() []byte {
+	if i.err != nil || i.dir <= dirEOI {
+		return nil
+	}
+	return i.value
+}
+
+func (i *blockIter) Release() {
+	if i.dir != dirReleased {
+		i.tr = nil
+		i.block = nil
+		i.prevNode = nil
+		i.prevKeys = nil
+		i.key = nil
+		i.value = nil
+		i.dir = dirReleased
+		if i.blockReleaser != nil {
+			i.blockReleaser.Release()
+			i.blockReleaser = nil
+		}
+		if i.releaser != nil {
+			i.releaser.Release()
+			i.releaser = nil
+		}
+	}
+}
+
+func (i *blockIter) SetReleaser(releaser util.Releaser) {
+	if i.dir == dirReleased {
+		panic(util.ErrReleased)
+	}
+	if i.releaser != nil && releaser != nil {
+		panic(util.ErrHasReleaser)
+	}
+	i.releaser = releaser
+}
+
+func (i *blockIter) Valid() bool {
+	return i.err == nil && (i.dir == dirBackward || i.dir == dirForward)
+}
+
+func (i *blockIter) Error() error {
+	return i.err
+}
+
+type filterBlock struct {
+	bpool      *util.BufferPool
+	data       []byte
+	oOffset    int
+	baseLg     uint
+	filtersNum int
+}
+
+func (b *filterBlock) contains(filter filter.Filter, offset uint64, key []byte) bool {
+	i := int(offset >> b.baseLg)
+	if i < b.filtersNum {
+		o := b.data[b.oOffset+i*4:]
+		n := int(binary.LittleEndian.Uint32(o))
+		m := int(binary.LittleEndian.Uint32(o[4:]))
+		if n < m && m <= b.oOffset {
+			return filter.Contains(b.data[n:m], key)
+		} else if n == m {
+			return false
+		}
+	}
+	return true
+}
+
+func (b *filterBlock) Release() {
+	b.bpool.Put(b.data)
+	b.bpool = nil
+	b.data = nil
+}
+
+type indexIter struct {
+	*blockIter
+	tr    *Reader
+	slice *util.Range
+	// Options
+	fillCache bool
+}
+
+func (i *indexIter) Get() iterator.Iterator {
+	value := i.Value()
+	if value == nil {
+		return nil
+	}
+	dataBH, n := decodeBlockHandle(value)
+	if n == 0 {
+		return iterator.NewEmptyIterator(i.tr.newErrCorruptedBH(i.tr.indexBH, "bad data block handle"))
+	}
+
+	var slice *util.Range
+	if i.slice != nil && (i.blockIter.isFirst() || i.blockIter.isLast()) {
+		slice = i.slice
+	}
+	return i.tr.getDataIterErr(dataBH, slice, i.tr.verifyChecksum, i.fillCache)
+}
+
+// Reader is a table reader.
+type Reader struct {
+	mu     sync.RWMutex
+	fd     storage.FileDesc
+	reader io.ReaderAt
+	cache  *cache.NamespaceGetter
+	err    error
+	bpool  *util.BufferPool
+	// Options
+	o              *opt.Options
+	cmp            comparer.Comparer
+	filter         filter.Filter
+	verifyChecksum bool
+
+	dataEnd                   int64
+	metaBH, indexBH, filterBH blockHandle
+	indexBlock                *block
+	filterBlock               *filterBlock
+}
+
+func (r *Reader) blockKind(bh blockHandle) string {
+	switch bh.offset {
+	case r.metaBH.offset:
+		return "meta-block"
+	case r.indexBH.offset:
+		return "index-block"
+	case r.filterBH.offset:
+		if r.filterBH.length > 0 {
+			return "filter-block"
+		}
+	}
+	return "data-block"
+}
+
+func (r *Reader) newErrCorrupted(pos, size int64, kind, reason string) error {
+	return &errors.ErrCorrupted{Fd: r.fd, Err: &ErrCorrupted{Pos: pos, Size: size, Kind: kind, Reason: reason}}
+}
+
+func (r *Reader) newErrCorruptedBH(bh blockHandle, reason string) error {
+	return r.newErrCorrupted(int64(bh.offset), int64(bh.length), r.blockKind(bh), reason)
+}
+
+func (r *Reader) fixErrCorruptedBH(bh blockHandle, err error) error {
+	if cerr, ok := err.(*ErrCorrupted); ok {
+		cerr.Pos = int64(bh.offset)
+		cerr.Size = int64(bh.length)
+		cerr.Kind = r.blockKind(bh)
+		return &errors.ErrCorrupted{Fd: r.fd, Err: cerr}
+	}
+	return err
+}
+
+func (r *Reader) readRawBlock(bh blockHandle, verifyChecksum bool) ([]byte, error) {
+	data := r.bpool.Get(int(bh.length + blockTrailerLen))
+	if _, err := r.reader.ReadAt(data, int64(bh.offset)); err != nil && err != io.EOF {
+		return nil, err
+	}
+
+	if verifyChecksum {
+		n := bh.length + 1
+		checksum0 := binary.LittleEndian.Uint32(data[n:])
+		checksum1 := util.NewCRC(data[:n]).Value()
+		if checksum0 != checksum1 {
+			r.bpool.Put(data)
+			return nil, r.newErrCorruptedBH(bh, fmt.Sprintf("checksum mismatch, want=%#x got=%#x", checksum0, checksum1))
+		}
+	}
+
+	switch data[bh.length] {
+	case blockTypeNoCompression:
+		data = data[:bh.length]
+	case blockTypeSnappyCompression:
+		decLen, err := snappy.DecodedLen(data[:bh.length])
+		if err != nil {
+			r.bpool.Put(data)
+			return nil, r.newErrCorruptedBH(bh, err.Error())
+		}
+		decData := r.bpool.Get(decLen)
+		decData, err = snappy.Decode(decData, data[:bh.length])
+		r.bpool.Put(data)
+		if err != nil {
+			r.bpool.Put(decData)
+			return nil, r.newErrCorruptedBH(bh, err.Error())
+		}
+		data = decData
+	default:
+		r.bpool.Put(data)
+		return nil, r.newErrCorruptedBH(bh, fmt.Sprintf("unknown compression type %#x", data[bh.length]))
+	}
+	return data, nil
+}
+
+func (r *Reader) readBlock(bh blockHandle, verifyChecksum bool) (*block, error) {
+	data, err := r.readRawBlock(bh, verifyChecksum)
+	if err != nil {
+		return nil, err
+	}
+	restartsLen := int(binary.LittleEndian.Uint32(data[len(data)-4:]))
+	b := &block{
+		bpool:          r.bpool,
+		bh:             bh,
+		data:           data,
+		restartsLen:    restartsLen,
+		restartsOffset: len(data) - (restartsLen+1)*4,
+	}
+	return b, nil
+}
+
+func (r *Reader) readBlockCached(bh blockHandle, verifyChecksum, fillCache bool) (*block, util.Releaser, error) {
+	if r.cache != nil {
+		var (
+			err error
+			ch  *cache.Handle
+		)
+		if fillCache {
+			ch = r.cache.Get(bh.offset, func() (size int, value cache.Value) {
+				var b *block
+				b, err = r.readBlock(bh, verifyChecksum)
+				if err != nil {
+					return 0, nil
+				}
+				return cap(b.data), b
+			})
+		} else {
+			ch = r.cache.Get(bh.offset, nil)
+		}
+		if ch != nil {
+			b, ok := ch.Value().(*block)
+			if !ok {
+				ch.Release()
+				return nil, nil, errors.New("leveldb/table: inconsistent block type")
+			}
+			return b, ch, err
+		} else if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	b, err := r.readBlock(bh, verifyChecksum)
+	return b, b, err
+}
+
+func (r *Reader) readFilterBlock(bh blockHandle) (*filterBlock, error) {
+	data, err := r.readRawBlock(bh, true)
+	if err != nil {
+		return nil, err
+	}
+	n := len(data)
+	if n < 5 {
+		return nil, r.newErrCorruptedBH(bh, "too short")
+	}
+	m := n - 5
+	oOffset := int(binary.LittleEndian.Uint32(data[m:]))
+	if oOffset > m {
+		return nil, r.newErrCorruptedBH(bh, "invalid data-offsets offset")
+	}
+	b := &filterBlock{
+		bpool:      r.bpool,
+		data:       data,
+		oOffset:    oOffset,
+		baseLg:     uint(data[n-1]),
+		filtersNum: (m - oOffset) / 4,
+	}
+	return b, nil
+}
+
+func (r *Reader) readFilterBlockCached(bh blockHandle, fillCache bool) (*filterBlock, util.Releaser, error) {
+	if r.cache != nil {
+		var (
+			err error
+			ch  *cache.Handle
+		)
+		if fillCache {
+			ch = r.cache.Get(bh.offset, func() (size int, value cache.Value) {
+				var b *filterBlock
+				b, err = r.readFilterBlock(bh)
+				if err != nil {
+					return 0, nil
+				}
+				return cap(b.data), b
+			})
+		} else {
+			ch = r.cache.Get(bh.offset, nil)
+		}
+		if ch != nil {
+			b, ok := ch.Value().(*filterBlock)
+			if !ok {
+				ch.Release()
+				return nil, nil, errors.New("leveldb/table: inconsistent block type")
+			}
+			return b, ch, err
+		} else if err != nil {
+			return nil, nil, err
+		}
+	}
+
+	b, err := r.readFilterBlock(bh)
+	return b, b, err
+}
+
+func (r *Reader) getIndexBlock(fillCache bool) (b *block, rel util.Releaser, err error) {
+	if r.indexBlock == nil {
+		return r.readBlockCached(r.indexBH, true, fillCache)
+	}
+	return r.indexBlock, util.NoopReleaser{}, nil
+}
+
+func (r *Reader) getFilterBlock(fillCache bool) (*filterBlock, util.Releaser, error) {
+	if r.filterBlock == nil {
+		return r.readFilterBlockCached(r.filterBH, fillCache)
+	}
+	return r.filterBlock, util.NoopReleaser{}, nil
+}
+
+func (r *Reader) newBlockIter(b *block, bReleaser util.Releaser, slice *util.Range, inclLimit bool) *blockIter {
+	bi := &blockIter{
+		tr:            r,
+		block:         b,
+		blockReleaser: bReleaser,
+		// Valid key should never be nil.
+		key:             make([]byte, 0),
+		dir:             dirSOI,
+		riStart:         0,
+		riLimit:         b.restartsLen,
+		offsetStart:     0,
+		offsetRealStart: 0,
+		offsetLimit:     b.restartsOffset,
+	}
+	if slice != nil {
+		if slice.Start != nil {
+			if bi.Seek(slice.Start) {
+				bi.riStart = b.restartIndex(bi.restartIndex, b.restartsLen, bi.prevOffset)
+				bi.offsetStart = b.restartOffset(bi.riStart)
+				bi.offsetRealStart = bi.prevOffset
+			} else {
+				bi.riStart = b.restartsLen
+				bi.offsetStart = b.restartsOffset
+				bi.offsetRealStart = b.restartsOffset
+			}
+		}
+		if slice.Limit != nil {
+			if bi.Seek(slice.Limit) && (!inclLimit || bi.Next()) {
+				bi.offsetLimit = bi.prevOffset
+				bi.riLimit = bi.restartIndex + 1
+			}
+		}
+		bi.reset()
+		if bi.offsetStart > bi.offsetLimit {
+			bi.sErr(errors.New("leveldb/table: invalid slice range"))
+		}
+	}
+	return bi
+}
+
+func (r *Reader) getDataIter(dataBH blockHandle, slice *util.Range, verifyChecksum, fillCache bool) iterator.Iterator {
+	b, rel, err := r.readBlockCached(dataBH, verifyChecksum, fillCache)
+	if err != nil {
+		return iterator.NewEmptyIterator(err)
+	}
+	return r.newBlockIter(b, rel, slice, false)
+}
+
+func (r *Reader) getDataIterErr(dataBH blockHandle, slice *util.Range, verifyChecksum, fillCache bool) iterator.Iterator {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	if r.err != nil {
+		return iterator.NewEmptyIterator(r.err)
+	}
+
+	return r.getDataIter(dataBH, slice, verifyChecksum, fillCache)
+}
+
+// NewIterator creates an iterator from the table.
+//
+// Slice allows slicing the iterator to only contains keys in the given
+// range. A nil Range.Start is treated as a key before all keys in the
+// table. And a nil Range.Limit is treated as a key after all keys in
+// the table.
+//
+// The returned iterator is not safe for concurrent use and should be released
+// after use.
+//
+// Also read Iterator documentation of the leveldb/iterator package.
+func (r *Reader) NewIterator(slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	if r.err != nil {
+		return iterator.NewEmptyIterator(r.err)
+	}
+
+	fillCache := !ro.GetDontFillCache()
+	indexBlock, rel, err := r.getIndexBlock(fillCache)
+	if err != nil {
+		return iterator.NewEmptyIterator(err)
+	}
+	index := &indexIter{
+		blockIter: r.newBlockIter(indexBlock, rel, slice, true),
+		tr:        r,
+		slice:     slice,
+		fillCache: !ro.GetDontFillCache(),
+	}
+	return iterator.NewIndexedIterator(index, opt.GetStrict(r.o, ro, opt.StrictReader))
+}
+
+func (r *Reader) find(key []byte, filtered bool, ro *opt.ReadOptions, noValue bool) (rkey, value []byte, err error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	if r.err != nil {
+		err = r.err
+		return
+	}
+
+	indexBlock, rel, err := r.getIndexBlock(true)
+	if err != nil {
+		return
+	}
+	defer rel.Release()
+
+	index := r.newBlockIter(indexBlock, nil, nil, true)
+	defer index.Release()
+
+	if !index.Seek(key) {
+		if err = index.Error(); err == nil {
+			err = ErrNotFound
+		}
+		return
+	}
+
+	dataBH, n := decodeBlockHandle(index.Value())
+	if n == 0 {
+		r.err = r.newErrCorruptedBH(r.indexBH, "bad data block handle")
+		return nil, nil, r.err
+	}
+
+	// The filter should only used for exact match.
+	if filtered && r.filter != nil {
+		filterBlock, frel, ferr := r.getFilterBlock(true)
+		if ferr == nil {
+			if !filterBlock.contains(r.filter, dataBH.offset, key) {
+				frel.Release()
+				return nil, nil, ErrNotFound
+			}
+			frel.Release()
+		} else if !errors.IsCorrupted(ferr) {
+			return nil, nil, ferr
+		}
+	}
+
+	data := r.getDataIter(dataBH, nil, r.verifyChecksum, !ro.GetDontFillCache())
+	if !data.Seek(key) {
+		data.Release()
+		if err = data.Error(); err != nil {
+			return
+		}
+
+		// The nearest greater-than key is the first key of the next block.
+		if !index.Next() {
+			if err = index.Error(); err == nil {
+				err = ErrNotFound
+			}
+			return
+		}
+
+		dataBH, n = decodeBlockHandle(index.Value())
+		if n == 0 {
+			r.err = r.newErrCorruptedBH(r.indexBH, "bad data block handle")
+			return nil, nil, r.err
+		}
+
+		data = r.getDataIter(dataBH, nil, r.verifyChecksum, !ro.GetDontFillCache())
+		if !data.Next() {
+			data.Release()
+			if err = data.Error(); err == nil {
+				err = ErrNotFound
+			}
+			return
+		}
+	}
+
+	// Key doesn't use block buffer, no need to copy the buffer.
+	rkey = data.Key()
+	if !noValue {
+		if r.bpool == nil {
+			value = data.Value()
+		} else {
+			// Value does use block buffer, and since the buffer will be
+			// recycled, it need to be copied.
+			value = append([]byte{}, data.Value()...)
+		}
+	}
+	data.Release()
+	return
+}
+
+// Find finds key/value pair whose key is greater than or equal to the
+// given key. It returns ErrNotFound if the table doesn't contain
+// such pair.
+// If filtered is true then the nearest 'block' will be checked against
+// 'filter data' (if present) and will immediately return ErrNotFound if
+// 'filter data' indicates that such pair doesn't exist.
+//
+// The caller may modify the contents of the returned slice as it is its
+// own copy.
+// It is safe to modify the contents of the argument after Find returns.
+func (r *Reader) Find(key []byte, filtered bool, ro *opt.ReadOptions) (rkey, value []byte, err error) {
+	return r.find(key, filtered, ro, false)
+}
+
+// FindKey finds key that is greater than or equal to the given key.
+// It returns ErrNotFound if the table doesn't contain such key.
+// If filtered is true then the nearest 'block' will be checked against
+// 'filter data' (if present) and will immediately return ErrNotFound if
+// 'filter data' indicates that such key doesn't exist.
+//
+// The caller may modify the contents of the returned slice as it is its
+// own copy.
+// It is safe to modify the contents of the argument after Find returns.
+func (r *Reader) FindKey(key []byte, filtered bool, ro *opt.ReadOptions) (rkey []byte, err error) {
+	rkey, _, err = r.find(key, filtered, ro, true)
+	return
+}
+
+// Get gets the value for the given key. It returns errors.ErrNotFound
+// if the table does not contain the key.
+//
+// The caller may modify the contents of the returned slice as it is its
+// own copy.
+// It is safe to modify the contents of the argument after Find returns.
+func (r *Reader) Get(key []byte, ro *opt.ReadOptions) (value []byte, err error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	if r.err != nil {
+		err = r.err
+		return
+	}
+
+	rkey, value, err := r.find(key, false, ro, false)
+	if err == nil && r.cmp.Compare(rkey, key) != 0 {
+		value = nil
+		err = ErrNotFound
+	}
+	return
+}
+
+// OffsetOf returns approximate offset for the given key.
+//
+// It is safe to modify the contents of the argument after Get returns.
+func (r *Reader) OffsetOf(key []byte) (offset int64, err error) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	if r.err != nil {
+		err = r.err
+		return
+	}
+
+	indexBlock, rel, err := r.readBlockCached(r.indexBH, true, true)
+	if err != nil {
+		return
+	}
+	defer rel.Release()
+
+	index := r.newBlockIter(indexBlock, nil, nil, true)
+	defer index.Release()
+	if index.Seek(key) {
+		dataBH, n := decodeBlockHandle(index.Value())
+		if n == 0 {
+			r.err = r.newErrCorruptedBH(r.indexBH, "bad data block handle")
+			return
+		}
+		offset = int64(dataBH.offset)
+		return
+	}
+	err = index.Error()
+	if err == nil {
+		offset = r.dataEnd
+	}
+	return
+}
+
+// Release implements util.Releaser.
+// It also close the file if it is an io.Closer.
+func (r *Reader) Release() {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	if closer, ok := r.reader.(io.Closer); ok {
+		closer.Close()
+	}
+	if r.indexBlock != nil {
+		r.indexBlock.Release()
+		r.indexBlock = nil
+	}
+	if r.filterBlock != nil {
+		r.filterBlock.Release()
+		r.filterBlock = nil
+	}
+	r.reader = nil
+	r.cache = nil
+	r.bpool = nil
+	r.err = ErrReaderReleased
+}
+
+// NewReader creates a new initialized table reader for the file.
+// The fi, cache and bpool is optional and can be nil.
+//
+// The returned table reader instance is safe for concurrent use.
+func NewReader(f io.ReaderAt, size int64, fd storage.FileDesc, cache *cache.NamespaceGetter, bpool *util.BufferPool, o *opt.Options) (*Reader, error) {
+	if f == nil {
+		return nil, errors.New("leveldb/table: nil file")
+	}
+
+	r := &Reader{
+		fd:             fd,
+		reader:         f,
+		cache:          cache,
+		bpool:          bpool,
+		o:              o,
+		cmp:            o.GetComparer(),
+		verifyChecksum: o.GetStrict(opt.StrictBlockChecksum),
+	}
+
+	if size < footerLen {
+		r.err = r.newErrCorrupted(0, size, "table", "too small")
+		return r, nil
+	}
+
+	footerPos := size - footerLen
+	var footer [footerLen]byte
+	if _, err := r.reader.ReadAt(footer[:], footerPos); err != nil && err != io.EOF {
+		return nil, err
+	}
+	if string(footer[footerLen-len(magic):footerLen]) != magic {
+		r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad magic number")
+		return r, nil
+	}
+
+	var n int
+	// Decode the metaindex block handle.
+	r.metaBH, n = decodeBlockHandle(footer[:])
+	if n == 0 {
+		r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad metaindex block handle")
+		return r, nil
+	}
+
+	// Decode the index block handle.
+	r.indexBH, n = decodeBlockHandle(footer[n:])
+	if n == 0 {
+		r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad index block handle")
+		return r, nil
+	}
+
+	// Read metaindex block.
+	metaBlock, err := r.readBlock(r.metaBH, true)
+	if err != nil {
+		if errors.IsCorrupted(err) {
+			r.err = err
+			return r, nil
+		}
+		return nil, err
+	}
+
+	// Set data end.
+	r.dataEnd = int64(r.metaBH.offset)
+
+	// Read metaindex.
+	metaIter := r.newBlockIter(metaBlock, nil, nil, true)
+	for metaIter.Next() {
+		key := string(metaIter.Key())
+		if !strings.HasPrefix(key, "filter.") {
+			continue
+		}
+		fn := key[7:]
+		if f0 := o.GetFilter(); f0 != nil && f0.Name() == fn {
+			r.filter = f0
+		} else {
+			for _, f0 := range o.GetAltFilters() {
+				if f0.Name() == fn {
+					r.filter = f0
+					break
+				}
+			}
+		}
+		if r.filter != nil {
+			filterBH, n := decodeBlockHandle(metaIter.Value())
+			if n == 0 {
+				continue
+			}
+			r.filterBH = filterBH
+			// Update data end.
+			r.dataEnd = int64(filterBH.offset)
+			break
+		}
+	}
+	metaIter.Release()
+	metaBlock.Release()
+
+	// Cache index and filter block locally, since we don't have global cache.
+	if cache == nil {
+		r.indexBlock, err = r.readBlock(r.indexBH, true)
+		if err != nil {
+			if errors.IsCorrupted(err) {
+				r.err = err
+				return r, nil
+			}
+			return nil, err
+		}
+		if r.filter != nil {
+			r.filterBlock, err = r.readFilterBlock(r.filterBH)
+			if err != nil {
+				if !errors.IsCorrupted(err) {
+					return nil, err
+				}
+
+				// Don't use filter then.
+				r.filter = nil
+			}
+		}
+	}
+
+	return r, nil
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/table/table.go b/vendor/github.com/syndtr/goleveldb/leveldb/table/table.go
new file mode 100644
index 0000000000..beacdc1f02
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/table/table.go
@@ -0,0 +1,177 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package table allows read and write sorted key/value.
+package table
+
+import (
+	"encoding/binary"
+)
+
+/*
+Table:
+
+Table is consist of one or more data blocks, an optional filter block
+a metaindex block, an index block and a table footer. Metaindex block
+is a special block used to keep parameters of the table, such as filter
+block name and its block handle. Index block is a special block used to
+keep record of data blocks offset and length, index block use one as
+restart interval. The key used by index block are the last key of preceding
+block, shorter separator of adjacent blocks or shorter successor of the
+last key of the last block. Filter block is an optional block contains
+sequence of filter data generated by a filter generator.
+
+Table data structure:
+                                                         + optional
+                                                        /
+    +--------------+--------------+--------------+------+-------+-----------------+-------------+--------+
+    | data block 1 |      ...     | data block n | filter block | metaindex block | index block | footer |
+    +--------------+--------------+--------------+--------------+-----------------+-------------+--------+
+
+    Each block followed by a 5-bytes trailer contains compression type and checksum.
+
+Table block trailer:
+
+    +---------------------------+-------------------+
+    | compression type (1-byte) | checksum (4-byte) |
+    +---------------------------+-------------------+
+
+    The checksum is a CRC-32 computed using Castagnoli's polynomial. Compression
+    type also included in the checksum.
+
+Table footer:
+
+      +------------------- 40-bytes -------------------+
+     /                                                  \
+    +------------------------+--------------------+------+-----------------+
+    | metaindex block handle / index block handle / ---- | magic (8-bytes) |
+    +------------------------+--------------------+------+-----------------+
+
+    The magic are first 64-bit of SHA-1 sum of "http://code.google.com/p/leveldb/".
+
+NOTE: All fixed-length integer are little-endian.
+*/
+
+/*
+Block:
+
+Block is consist of one or more key/value entries and a block trailer.
+Block entry shares key prefix with its preceding key until a restart
+point reached. A block should contains at least one restart point.
+First restart point are always zero.
+
+Block data structure:
+
+      + restart point                 + restart point (depends on restart interval)
+     /                               /
+    +---------------+---------------+---------------+---------------+---------+
+    | block entry 1 | block entry 2 |      ...      | block entry n | trailer |
+    +---------------+---------------+---------------+---------------+---------+
+
+Key/value entry:
+
+              +---- key len ----+
+             /                   \
+    +-------+---------+-----------+---------+--------------------+--------------+----------------+
+    | shared (varint) | not shared (varint) | value len (varint) | key (varlen) | value (varlen) |
+    +-----------------+---------------------+--------------------+--------------+----------------+
+
+    Block entry shares key prefix with its preceding key:
+    Conditions:
+        restart_interval=2
+        entry one  : key=deck,value=v1
+        entry two  : key=dock,value=v2
+        entry three: key=duck,value=v3
+    The entries will be encoded as follow:
+
+      + restart point (offset=0)                                                 + restart point (offset=16)
+     /                                                                          /
+    +-----+-----+-----+----------+--------+-----+-----+-----+---------+--------+-----+-----+-----+----------+--------+
+    |  0  |  4  |  2  |  "deck"  |  "v1"  |  1  |  3  |  2  |  "ock"  |  "v2"  |  0  |  4  |  2  |  "duck"  |  "v3"  |
+    +-----+-----+-----+----------+--------+-----+-----+-----+---------+--------+-----+-----+-----+----------+--------+
+     \                                   / \                                  / \                                   /
+      +----------- entry one -----------+   +----------- entry two ----------+   +---------- entry three ----------+
+
+    The block trailer will contains two restart points:
+
+    +------------+-----------+--------+
+    |     0      |    16     |   2    |
+    +------------+-----------+---+----+
+     \                      /     \
+      +-- restart points --+       + restart points length
+
+Block trailer:
+
+      +-- 4-bytes --+
+     /               \
+    +-----------------+-----------------+-----------------+------------------------------+
+    | restart point 1 |       ....      | restart point n | restart points len (4-bytes) |
+    +-----------------+-----------------+-----------------+------------------------------+
+
+
+NOTE: All fixed-length integer are little-endian.
+*/
+
+/*
+Filter block:
+
+Filter block consist of one or more filter data and a filter block trailer.
+The trailer contains filter data offsets, a trailer offset and a 1-byte base Lg.
+
+Filter block data structure:
+
+      + offset 1      + offset 2      + offset n      + trailer offset
+     /               /               /               /
+    +---------------+---------------+---------------+---------+
+    | filter data 1 |      ...      | filter data n | trailer |
+    +---------------+---------------+---------------+---------+
+
+Filter block trailer:
+
+      +- 4-bytes -+
+     /             \
+    +---------------+---------------+---------------+-------------------------------+------------------+
+    | data 1 offset |      ....     | data n offset | data-offsets offset (4-bytes) | base Lg (1-byte) |
+    +-------------- +---------------+---------------+-------------------------------+------------------+
+
+
+NOTE: All fixed-length integer are little-endian.
+*/
+
+const (
+	blockTrailerLen = 5
+	footerLen       = 48
+
+	magic = "\x57\xfb\x80\x8b\x24\x75\x47\xdb"
+
+	// The block type gives the per-block compression format.
+	// These constants are part of the file format and should not be changed.
+	blockTypeNoCompression     = 0
+	blockTypeSnappyCompression = 1
+
+	// Generate new filter every 2KB of data
+	filterBaseLg = 11
+	filterBase   = 1 << filterBaseLg
+)
+
+type blockHandle struct {
+	offset, length uint64
+}
+
+func decodeBlockHandle(src []byte) (blockHandle, int) {
+	offset, n := binary.Uvarint(src)
+	length, m := binary.Uvarint(src[n:])
+	if n == 0 || m == 0 {
+		return blockHandle{}, 0
+	}
+	return blockHandle{offset, length}, n + m
+}
+
+func encodeBlockHandle(dst []byte, b blockHandle) int {
+	n := binary.PutUvarint(dst, b.offset)
+	m := binary.PutUvarint(dst[n:], b.length)
+	return n + m
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/table/writer.go b/vendor/github.com/syndtr/goleveldb/leveldb/table/writer.go
new file mode 100644
index 0000000000..b96b271d8d
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/table/writer.go
@@ -0,0 +1,375 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package table
+
+import (
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+
+	"github.com/golang/snappy"
+
+	"github.com/syndtr/goleveldb/leveldb/comparer"
+	"github.com/syndtr/goleveldb/leveldb/filter"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+func sharedPrefixLen(a, b []byte) int {
+	i, n := 0, len(a)
+	if n > len(b) {
+		n = len(b)
+	}
+	for i < n && a[i] == b[i] {
+		i++
+	}
+	return i
+}
+
+type blockWriter struct {
+	restartInterval int
+	buf             util.Buffer
+	nEntries        int
+	prevKey         []byte
+	restarts        []uint32
+	scratch         []byte
+}
+
+func (w *blockWriter) append(key, value []byte) {
+	nShared := 0
+	if w.nEntries%w.restartInterval == 0 {
+		w.restarts = append(w.restarts, uint32(w.buf.Len()))
+	} else {
+		nShared = sharedPrefixLen(w.prevKey, key)
+	}
+	n := binary.PutUvarint(w.scratch[0:], uint64(nShared))
+	n += binary.PutUvarint(w.scratch[n:], uint64(len(key)-nShared))
+	n += binary.PutUvarint(w.scratch[n:], uint64(len(value)))
+	w.buf.Write(w.scratch[:n])
+	w.buf.Write(key[nShared:])
+	w.buf.Write(value)
+	w.prevKey = append(w.prevKey[:0], key...)
+	w.nEntries++
+}
+
+func (w *blockWriter) finish() {
+	// Write restarts entry.
+	if w.nEntries == 0 {
+		// Must have at least one restart entry.
+		w.restarts = append(w.restarts, 0)
+	}
+	w.restarts = append(w.restarts, uint32(len(w.restarts)))
+	for _, x := range w.restarts {
+		buf4 := w.buf.Alloc(4)
+		binary.LittleEndian.PutUint32(buf4, x)
+	}
+}
+
+func (w *blockWriter) reset() {
+	w.buf.Reset()
+	w.nEntries = 0
+	w.restarts = w.restarts[:0]
+}
+
+func (w *blockWriter) bytesLen() int {
+	restartsLen := len(w.restarts)
+	if restartsLen == 0 {
+		restartsLen = 1
+	}
+	return w.buf.Len() + 4*restartsLen + 4
+}
+
+type filterWriter struct {
+	generator filter.FilterGenerator
+	buf       util.Buffer
+	nKeys     int
+	offsets   []uint32
+}
+
+func (w *filterWriter) add(key []byte) {
+	if w.generator == nil {
+		return
+	}
+	w.generator.Add(key)
+	w.nKeys++
+}
+
+func (w *filterWriter) flush(offset uint64) {
+	if w.generator == nil {
+		return
+	}
+	for x := int(offset / filterBase); x > len(w.offsets); {
+		w.generate()
+	}
+}
+
+func (w *filterWriter) finish() {
+	if w.generator == nil {
+		return
+	}
+	// Generate last keys.
+
+	if w.nKeys > 0 {
+		w.generate()
+	}
+	w.offsets = append(w.offsets, uint32(w.buf.Len()))
+	for _, x := range w.offsets {
+		buf4 := w.buf.Alloc(4)
+		binary.LittleEndian.PutUint32(buf4, x)
+	}
+	w.buf.WriteByte(filterBaseLg)
+}
+
+func (w *filterWriter) generate() {
+	// Record offset.
+	w.offsets = append(w.offsets, uint32(w.buf.Len()))
+	// Generate filters.
+	if w.nKeys > 0 {
+		w.generator.Generate(&w.buf)
+		w.nKeys = 0
+	}
+}
+
+// Writer is a table writer.
+type Writer struct {
+	writer io.Writer
+	err    error
+	// Options
+	cmp         comparer.Comparer
+	filter      filter.Filter
+	compression opt.Compression
+	blockSize   int
+
+	dataBlock   blockWriter
+	indexBlock  blockWriter
+	filterBlock filterWriter
+	pendingBH   blockHandle
+	offset      uint64
+	nEntries    int
+	// Scratch allocated enough for 5 uvarint. Block writer should not use
+	// first 20-bytes since it will be used to encode block handle, which
+	// then passed to the block writer itself.
+	scratch            [50]byte
+	comparerScratch    []byte
+	compressionScratch []byte
+}
+
+func (w *Writer) writeBlock(buf *util.Buffer, compression opt.Compression) (bh blockHandle, err error) {
+	// Compress the buffer if necessary.
+	var b []byte
+	if compression == opt.SnappyCompression {
+		// Allocate scratch enough for compression and block trailer.
+		if n := snappy.MaxEncodedLen(buf.Len()) + blockTrailerLen; len(w.compressionScratch) < n {
+			w.compressionScratch = make([]byte, n)
+		}
+		compressed := snappy.Encode(w.compressionScratch, buf.Bytes())
+		n := len(compressed)
+		b = compressed[:n+blockTrailerLen]
+		b[n] = blockTypeSnappyCompression
+	} else {
+		tmp := buf.Alloc(blockTrailerLen)
+		tmp[0] = blockTypeNoCompression
+		b = buf.Bytes()
+	}
+
+	// Calculate the checksum.
+	n := len(b) - 4
+	checksum := util.NewCRC(b[:n]).Value()
+	binary.LittleEndian.PutUint32(b[n:], checksum)
+
+	// Write the buffer to the file.
+	_, err = w.writer.Write(b)
+	if err != nil {
+		return
+	}
+	bh = blockHandle{w.offset, uint64(len(b) - blockTrailerLen)}
+	w.offset += uint64(len(b))
+	return
+}
+
+func (w *Writer) flushPendingBH(key []byte) {
+	if w.pendingBH.length == 0 {
+		return
+	}
+	var separator []byte
+	if len(key) == 0 {
+		separator = w.cmp.Successor(w.comparerScratch[:0], w.dataBlock.prevKey)
+	} else {
+		separator = w.cmp.Separator(w.comparerScratch[:0], w.dataBlock.prevKey, key)
+	}
+	if separator == nil {
+		separator = w.dataBlock.prevKey
+	} else {
+		w.comparerScratch = separator
+	}
+	n := encodeBlockHandle(w.scratch[:20], w.pendingBH)
+	// Append the block handle to the index block.
+	w.indexBlock.append(separator, w.scratch[:n])
+	// Reset prev key of the data block.
+	w.dataBlock.prevKey = w.dataBlock.prevKey[:0]
+	// Clear pending block handle.
+	w.pendingBH = blockHandle{}
+}
+
+func (w *Writer) finishBlock() error {
+	w.dataBlock.finish()
+	bh, err := w.writeBlock(&w.dataBlock.buf, w.compression)
+	if err != nil {
+		return err
+	}
+	w.pendingBH = bh
+	// Reset the data block.
+	w.dataBlock.reset()
+	// Flush the filter block.
+	w.filterBlock.flush(w.offset)
+	return nil
+}
+
+// Append appends key/value pair to the table. The keys passed must
+// be in increasing order.
+//
+// It is safe to modify the contents of the arguments after Append returns.
+func (w *Writer) Append(key, value []byte) error {
+	if w.err != nil {
+		return w.err
+	}
+	if w.nEntries > 0 && w.cmp.Compare(w.dataBlock.prevKey, key) >= 0 {
+		w.err = fmt.Errorf("leveldb/table: Writer: keys are not in increasing order: %q, %q", w.dataBlock.prevKey, key)
+		return w.err
+	}
+
+	w.flushPendingBH(key)
+	// Append key/value pair to the data block.
+	w.dataBlock.append(key, value)
+	// Add key to the filter block.
+	w.filterBlock.add(key)
+
+	// Finish the data block if block size target reached.
+	if w.dataBlock.bytesLen() >= w.blockSize {
+		if err := w.finishBlock(); err != nil {
+			w.err = err
+			return w.err
+		}
+	}
+	w.nEntries++
+	return nil
+}
+
+// BlocksLen returns number of blocks written so far.
+func (w *Writer) BlocksLen() int {
+	n := w.indexBlock.nEntries
+	if w.pendingBH.length > 0 {
+		// Includes the pending block.
+		n++
+	}
+	return n
+}
+
+// EntriesLen returns number of entries added so far.
+func (w *Writer) EntriesLen() int {
+	return w.nEntries
+}
+
+// BytesLen returns number of bytes written so far.
+func (w *Writer) BytesLen() int {
+	return int(w.offset)
+}
+
+// Close will finalize the table. Calling Append is not possible
+// after Close, but calling BlocksLen, EntriesLen and BytesLen
+// is still possible.
+func (w *Writer) Close() error {
+	if w.err != nil {
+		return w.err
+	}
+
+	// Write the last data block. Or empty data block if there
+	// aren't any data blocks at all.
+	if w.dataBlock.nEntries > 0 || w.nEntries == 0 {
+		if err := w.finishBlock(); err != nil {
+			w.err = err
+			return w.err
+		}
+	}
+	w.flushPendingBH(nil)
+
+	// Write the filter block.
+	var filterBH blockHandle
+	w.filterBlock.finish()
+	if buf := &w.filterBlock.buf; buf.Len() > 0 {
+		filterBH, w.err = w.writeBlock(buf, opt.NoCompression)
+		if w.err != nil {
+			return w.err
+		}
+	}
+
+	// Write the metaindex block.
+	if filterBH.length > 0 {
+		key := []byte("filter." + w.filter.Name())
+		n := encodeBlockHandle(w.scratch[:20], filterBH)
+		w.dataBlock.append(key, w.scratch[:n])
+	}
+	w.dataBlock.finish()
+	metaindexBH, err := w.writeBlock(&w.dataBlock.buf, w.compression)
+	if err != nil {
+		w.err = err
+		return w.err
+	}
+
+	// Write the index block.
+	w.indexBlock.finish()
+	indexBH, err := w.writeBlock(&w.indexBlock.buf, w.compression)
+	if err != nil {
+		w.err = err
+		return w.err
+	}
+
+	// Write the table footer.
+	footer := w.scratch[:footerLen]
+	for i := range footer {
+		footer[i] = 0
+	}
+	n := encodeBlockHandle(footer, metaindexBH)
+	encodeBlockHandle(footer[n:], indexBH)
+	copy(footer[footerLen-len(magic):], magic)
+	if _, err := w.writer.Write(footer); err != nil {
+		w.err = err
+		return w.err
+	}
+	w.offset += footerLen
+
+	w.err = errors.New("leveldb/table: writer is closed")
+	return nil
+}
+
+// NewWriter creates a new initialized table writer for the file.
+//
+// Table writer is not safe for concurrent use.
+func NewWriter(f io.Writer, o *opt.Options) *Writer {
+	w := &Writer{
+		writer:          f,
+		cmp:             o.GetComparer(),
+		filter:          o.GetFilter(),
+		compression:     o.GetCompression(),
+		blockSize:       o.GetBlockSize(),
+		comparerScratch: make([]byte, 0),
+	}
+	// data block
+	w.dataBlock.restartInterval = o.GetBlockRestartInterval()
+	// The first 20-bytes are used for encoding block handle.
+	w.dataBlock.scratch = w.scratch[20:]
+	// index block
+	w.indexBlock.restartInterval = 1
+	w.indexBlock.scratch = w.scratch[20:]
+	// filter block
+	if w.filter != nil {
+		w.filterBlock.generator = w.filter.NewGenerator()
+		w.filterBlock.flush(0)
+	}
+	return w
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util.go b/vendor/github.com/syndtr/goleveldb/leveldb/util.go
new file mode 100644
index 0000000000..0e2b519e5c
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util.go
@@ -0,0 +1,98 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"fmt"
+	"sort"
+
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+func shorten(str string) string {
+	if len(str) <= 8 {
+		return str
+	}
+	return str[:3] + ".." + str[len(str)-3:]
+}
+
+var bunits = [...]string{"", "Ki", "Mi", "Gi", "Ti"}
+
+func shortenb(bytes int) string {
+	i := 0
+	for ; bytes > 1024 && i < 4; i++ {
+		bytes /= 1024
+	}
+	return fmt.Sprintf("%d%sB", bytes, bunits[i])
+}
+
+func sshortenb(bytes int) string {
+	if bytes == 0 {
+		return "~"
+	}
+	sign := "+"
+	if bytes < 0 {
+		sign = "-"
+		bytes *= -1
+	}
+	i := 0
+	for ; bytes > 1024 && i < 4; i++ {
+		bytes /= 1024
+	}
+	return fmt.Sprintf("%s%d%sB", sign, bytes, bunits[i])
+}
+
+func sint(x int) string {
+	if x == 0 {
+		return "~"
+	}
+	sign := "+"
+	if x < 0 {
+		sign = "-"
+		x *= -1
+	}
+	return fmt.Sprintf("%s%d", sign, x)
+}
+
+func minInt(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func maxInt(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+type fdSorter []storage.FileDesc
+
+func (p fdSorter) Len() int {
+	return len(p)
+}
+
+func (p fdSorter) Less(i, j int) bool {
+	return p[i].Num < p[j].Num
+}
+
+func (p fdSorter) Swap(i, j int) {
+	p[i], p[j] = p[j], p[i]
+}
+
+func sortFds(fds []storage.FileDesc) {
+	sort.Sort(fdSorter(fds))
+}
+
+func ensureBuffer(b []byte, n int) []byte {
+	if cap(b) < n {
+		return make([]byte, n)
+	}
+	return b[:n]
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer.go
new file mode 100644
index 0000000000..21de242552
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer.go
@@ -0,0 +1,293 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package util
+
+// This a copy of Go std bytes.Buffer with some modification
+// and some features stripped.
+
+import (
+	"bytes"
+	"io"
+)
+
+// A Buffer is a variable-sized buffer of bytes with Read and Write methods.
+// The zero value for Buffer is an empty buffer ready to use.
+type Buffer struct {
+	buf       []byte   // contents are the bytes buf[off : len(buf)]
+	off       int      // read at &buf[off], write at &buf[len(buf)]
+	bootstrap [64]byte // memory to hold first slice; helps small buffers (Printf) avoid allocation.
+}
+
+// Bytes returns a slice of the contents of the unread portion of the buffer;
+// len(b.Bytes()) == b.Len().  If the caller changes the contents of the
+// returned slice, the contents of the buffer will change provided there
+// are no intervening method calls on the Buffer.
+func (b *Buffer) Bytes() []byte { return b.buf[b.off:] }
+
+// String returns the contents of the unread portion of the buffer
+// as a string.  If the Buffer is a nil pointer, it returns "<nil>".
+func (b *Buffer) String() string {
+	if b == nil {
+		// Special case, useful in debugging.
+		return "<nil>"
+	}
+	return string(b.buf[b.off:])
+}
+
+// Len returns the number of bytes of the unread portion of the buffer;
+// b.Len() == len(b.Bytes()).
+func (b *Buffer) Len() int { return len(b.buf) - b.off }
+
+// Truncate discards all but the first n unread bytes from the buffer.
+// It panics if n is negative or greater than the length of the buffer.
+func (b *Buffer) Truncate(n int) {
+	switch {
+	case n < 0 || n > b.Len():
+		panic("leveldb/util.Buffer: truncation out of range")
+	case n == 0:
+		// Reuse buffer space.
+		b.off = 0
+	}
+	b.buf = b.buf[0 : b.off+n]
+}
+
+// Reset resets the buffer so it has no content.
+// b.Reset() is the same as b.Truncate(0).
+func (b *Buffer) Reset() { b.Truncate(0) }
+
+// grow grows the buffer to guarantee space for n more bytes.
+// It returns the index where bytes should be written.
+// If the buffer can't grow it will panic with bytes.ErrTooLarge.
+func (b *Buffer) grow(n int) int {
+	m := b.Len()
+	// If buffer is empty, reset to recover space.
+	if m == 0 && b.off != 0 {
+		b.Truncate(0)
+	}
+	if len(b.buf)+n > cap(b.buf) {
+		var buf []byte
+		if b.buf == nil && n <= len(b.bootstrap) {
+			buf = b.bootstrap[0:]
+		} else if m+n <= cap(b.buf)/2 {
+			// We can slide things down instead of allocating a new
+			// slice. We only need m+n <= cap(b.buf) to slide, but
+			// we instead let capacity get twice as large so we
+			// don't spend all our time copying.
+			copy(b.buf[:], b.buf[b.off:])
+			buf = b.buf[:m]
+		} else {
+			// not enough space anywhere
+			buf = makeSlice(2*cap(b.buf) + n)
+			copy(buf, b.buf[b.off:])
+		}
+		b.buf = buf
+		b.off = 0
+	}
+	b.buf = b.buf[0 : b.off+m+n]
+	return b.off + m
+}
+
+// Alloc allocs n bytes of slice from the buffer, growing the buffer as
+// needed. If n is negative, Alloc will panic.
+// If the buffer can't grow it will panic with bytes.ErrTooLarge.
+func (b *Buffer) Alloc(n int) []byte {
+	if n < 0 {
+		panic("leveldb/util.Buffer.Alloc: negative count")
+	}
+	m := b.grow(n)
+	return b.buf[m:]
+}
+
+// Grow grows the buffer's capacity, if necessary, to guarantee space for
+// another n bytes. After Grow(n), at least n bytes can be written to the
+// buffer without another allocation.
+// If n is negative, Grow will panic.
+// If the buffer can't grow it will panic with bytes.ErrTooLarge.
+func (b *Buffer) Grow(n int) {
+	if n < 0 {
+		panic("leveldb/util.Buffer.Grow: negative count")
+	}
+	m := b.grow(n)
+	b.buf = b.buf[0:m]
+}
+
+// Write appends the contents of p to the buffer, growing the buffer as
+// needed. The return value n is the length of p; err is always nil. If the
+// buffer becomes too large, Write will panic with bytes.ErrTooLarge.
+func (b *Buffer) Write(p []byte) (n int, err error) {
+	m := b.grow(len(p))
+	return copy(b.buf[m:], p), nil
+}
+
+// MinRead is the minimum slice size passed to a Read call by
+// Buffer.ReadFrom.  As long as the Buffer has at least MinRead bytes beyond
+// what is required to hold the contents of r, ReadFrom will not grow the
+// underlying buffer.
+const MinRead = 512
+
+// ReadFrom reads data from r until EOF and appends it to the buffer, growing
+// the buffer as needed. The return value n is the number of bytes read. Any
+// error except io.EOF encountered during the read is also returned. If the
+// buffer becomes too large, ReadFrom will panic with bytes.ErrTooLarge.
+func (b *Buffer) ReadFrom(r io.Reader) (n int64, err error) {
+	// If buffer is empty, reset to recover space.
+	if b.off >= len(b.buf) {
+		b.Truncate(0)
+	}
+	for {
+		if free := cap(b.buf) - len(b.buf); free < MinRead {
+			// not enough space at end
+			newBuf := b.buf
+			if b.off+free < MinRead {
+				// not enough space using beginning of buffer;
+				// double buffer capacity
+				newBuf = makeSlice(2*cap(b.buf) + MinRead)
+			}
+			copy(newBuf, b.buf[b.off:])
+			b.buf = newBuf[:len(b.buf)-b.off]
+			b.off = 0
+		}
+		m, e := r.Read(b.buf[len(b.buf):cap(b.buf)])
+		b.buf = b.buf[0 : len(b.buf)+m]
+		n += int64(m)
+		if e == io.EOF {
+			break
+		}
+		if e != nil {
+			return n, e
+		}
+	}
+	return n, nil // err is EOF, so return nil explicitly
+}
+
+// makeSlice allocates a slice of size n. If the allocation fails, it panics
+// with bytes.ErrTooLarge.
+func makeSlice(n int) []byte {
+	// If the make fails, give a known error.
+	defer func() {
+		if recover() != nil {
+			panic(bytes.ErrTooLarge)
+		}
+	}()
+	return make([]byte, n)
+}
+
+// WriteTo writes data to w until the buffer is drained or an error occurs.
+// The return value n is the number of bytes written; it always fits into an
+// int, but it is int64 to match the io.WriterTo interface. Any error
+// encountered during the write is also returned.
+func (b *Buffer) WriteTo(w io.Writer) (n int64, err error) {
+	if b.off < len(b.buf) {
+		nBytes := b.Len()
+		m, e := w.Write(b.buf[b.off:])
+		if m > nBytes {
+			panic("leveldb/util.Buffer.WriteTo: invalid Write count")
+		}
+		b.off += m
+		n = int64(m)
+		if e != nil {
+			return n, e
+		}
+		// all bytes should have been written, by definition of
+		// Write method in io.Writer
+		if m != nBytes {
+			return n, io.ErrShortWrite
+		}
+	}
+	// Buffer is now empty; reset.
+	b.Truncate(0)
+	return
+}
+
+// WriteByte appends the byte c to the buffer, growing the buffer as needed.
+// The returned error is always nil, but is included to match bufio.Writer's
+// WriteByte. If the buffer becomes too large, WriteByte will panic with
+// bytes.ErrTooLarge.
+func (b *Buffer) WriteByte(c byte) error {
+	m := b.grow(1)
+	b.buf[m] = c
+	return nil
+}
+
+// Read reads the next len(p) bytes from the buffer or until the buffer
+// is drained.  The return value n is the number of bytes read.  If the
+// buffer has no data to return, err is io.EOF (unless len(p) is zero);
+// otherwise it is nil.
+func (b *Buffer) Read(p []byte) (n int, err error) {
+	if b.off >= len(b.buf) {
+		// Buffer is empty, reset to recover space.
+		b.Truncate(0)
+		if len(p) == 0 {
+			return
+		}
+		return 0, io.EOF
+	}
+	n = copy(p, b.buf[b.off:])
+	b.off += n
+	return
+}
+
+// Next returns a slice containing the next n bytes from the buffer,
+// advancing the buffer as if the bytes had been returned by Read.
+// If there are fewer than n bytes in the buffer, Next returns the entire buffer.
+// The slice is only valid until the next call to a read or write method.
+func (b *Buffer) Next(n int) []byte {
+	m := b.Len()
+	if n > m {
+		n = m
+	}
+	data := b.buf[b.off : b.off+n]
+	b.off += n
+	return data
+}
+
+// ReadByte reads and returns the next byte from the buffer.
+// If no byte is available, it returns error io.EOF.
+func (b *Buffer) ReadByte() (c byte, err error) {
+	if b.off >= len(b.buf) {
+		// Buffer is empty, reset to recover space.
+		b.Truncate(0)
+		return 0, io.EOF
+	}
+	c = b.buf[b.off]
+	b.off++
+	return c, nil
+}
+
+// ReadBytes reads until the first occurrence of delim in the input,
+// returning a slice containing the data up to and including the delimiter.
+// If ReadBytes encounters an error before finding a delimiter,
+// it returns the data read before the error and the error itself (often io.EOF).
+// ReadBytes returns err != nil if and only if the returned data does not end in
+// delim.
+func (b *Buffer) ReadBytes(delim byte) (line []byte, err error) {
+	slice, err := b.readSlice(delim)
+	// return a copy of slice. The buffer's backing array may
+	// be overwritten by later calls.
+	line = append(line, slice...)
+	return
+}
+
+// readSlice is like ReadBytes but returns a reference to internal buffer data.
+func (b *Buffer) readSlice(delim byte) (line []byte, err error) {
+	i := bytes.IndexByte(b.buf[b.off:], delim)
+	end := b.off + i + 1
+	if i < 0 {
+		end = len(b.buf)
+		err = io.EOF
+	}
+	line = b.buf[b.off:end]
+	b.off = end
+	return line, err
+}
+
+// NewBuffer creates and initializes a new Buffer using buf as its initial
+// contents.  It is intended to prepare a Buffer to read existing data.  It
+// can also be used to size the internal buffer for writing. To do that,
+// buf should have the desired capacity but a length of zero.
+//
+// In most cases, new(Buffer) (or just declaring a Buffer variable) is
+// sufficient to initialize a Buffer.
+func NewBuffer(buf []byte) *Buffer { return &Buffer{buf: buf} }
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer_pool.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer_pool.go
new file mode 100644
index 0000000000..2f3db974a7
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util/buffer_pool.go
@@ -0,0 +1,239 @@
+// Copyright (c) 2014, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package util
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type buffer struct {
+	b    []byte
+	miss int
+}
+
+// BufferPool is a 'buffer pool'.
+type BufferPool struct {
+	pool      [6]chan []byte
+	size      [5]uint32
+	sizeMiss  [5]uint32
+	sizeHalf  [5]uint32
+	baseline  [4]int
+	baseline0 int
+
+	mu     sync.RWMutex
+	closed bool
+	closeC chan struct{}
+
+	get     uint32
+	put     uint32
+	half    uint32
+	less    uint32
+	equal   uint32
+	greater uint32
+	miss    uint32
+}
+
+func (p *BufferPool) poolNum(n int) int {
+	if n <= p.baseline0 && n > p.baseline0/2 {
+		return 0
+	}
+	for i, x := range p.baseline {
+		if n <= x {
+			return i + 1
+		}
+	}
+	return len(p.baseline) + 1
+}
+
+// Get returns buffer with length of n.
+func (p *BufferPool) Get(n int) []byte {
+	if p == nil {
+		return make([]byte, n)
+	}
+
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+
+	if p.closed {
+		return make([]byte, n)
+	}
+
+	atomic.AddUint32(&p.get, 1)
+
+	poolNum := p.poolNum(n)
+	pool := p.pool[poolNum]
+	if poolNum == 0 {
+		// Fast path.
+		select {
+		case b := <-pool:
+			switch {
+			case cap(b) > n:
+				if cap(b)-n >= n {
+					atomic.AddUint32(&p.half, 1)
+					select {
+					case pool <- b:
+					default:
+					}
+					return make([]byte, n)
+				} else {
+					atomic.AddUint32(&p.less, 1)
+					return b[:n]
+				}
+			case cap(b) == n:
+				atomic.AddUint32(&p.equal, 1)
+				return b[:n]
+			default:
+				atomic.AddUint32(&p.greater, 1)
+			}
+		default:
+			atomic.AddUint32(&p.miss, 1)
+		}
+
+		return make([]byte, n, p.baseline0)
+	} else {
+		sizePtr := &p.size[poolNum-1]
+
+		select {
+		case b := <-pool:
+			switch {
+			case cap(b) > n:
+				if cap(b)-n >= n {
+					atomic.AddUint32(&p.half, 1)
+					sizeHalfPtr := &p.sizeHalf[poolNum-1]
+					if atomic.AddUint32(sizeHalfPtr, 1) == 20 {
+						atomic.StoreUint32(sizePtr, uint32(cap(b)/2))
+						atomic.StoreUint32(sizeHalfPtr, 0)
+					} else {
+						select {
+						case pool <- b:
+						default:
+						}
+					}
+					return make([]byte, n)
+				} else {
+					atomic.AddUint32(&p.less, 1)
+					return b[:n]
+				}
+			case cap(b) == n:
+				atomic.AddUint32(&p.equal, 1)
+				return b[:n]
+			default:
+				atomic.AddUint32(&p.greater, 1)
+				if uint32(cap(b)) >= atomic.LoadUint32(sizePtr) {
+					select {
+					case pool <- b:
+					default:
+					}
+				}
+			}
+		default:
+			atomic.AddUint32(&p.miss, 1)
+		}
+
+		if size := atomic.LoadUint32(sizePtr); uint32(n) > size {
+			if size == 0 {
+				atomic.CompareAndSwapUint32(sizePtr, 0, uint32(n))
+			} else {
+				sizeMissPtr := &p.sizeMiss[poolNum-1]
+				if atomic.AddUint32(sizeMissPtr, 1) == 20 {
+					atomic.StoreUint32(sizePtr, uint32(n))
+					atomic.StoreUint32(sizeMissPtr, 0)
+				}
+			}
+			return make([]byte, n)
+		} else {
+			return make([]byte, n, size)
+		}
+	}
+}
+
+// Put adds given buffer to the pool.
+func (p *BufferPool) Put(b []byte) {
+	if p == nil {
+		return
+	}
+
+	p.mu.RLock()
+	defer p.mu.RUnlock()
+
+	if p.closed {
+		return
+	}
+
+	atomic.AddUint32(&p.put, 1)
+
+	pool := p.pool[p.poolNum(cap(b))]
+	select {
+	case pool <- b:
+	default:
+	}
+
+}
+
+func (p *BufferPool) Close() {
+	if p == nil {
+		return
+	}
+
+	p.mu.Lock()
+	if !p.closed {
+		p.closed = true
+		p.closeC <- struct{}{}
+	}
+	p.mu.Unlock()
+}
+
+func (p *BufferPool) String() string {
+	if p == nil {
+		return "<nil>"
+	}
+
+	return fmt.Sprintf("BufferPool{B·%d Z·%v Zm·%v Zh·%v G·%d P·%d H·%d <·%d =·%d >·%d M·%d}",
+		p.baseline0, p.size, p.sizeMiss, p.sizeHalf, p.get, p.put, p.half, p.less, p.equal, p.greater, p.miss)
+}
+
+func (p *BufferPool) drain() {
+	ticker := time.NewTicker(2 * time.Second)
+	defer ticker.Stop()
+	for {
+		select {
+		case <-ticker.C:
+			for _, ch := range p.pool {
+				select {
+				case <-ch:
+				default:
+				}
+			}
+		case <-p.closeC:
+			close(p.closeC)
+			for _, ch := range p.pool {
+				close(ch)
+			}
+			return
+		}
+	}
+}
+
+// NewBufferPool creates a new initialized 'buffer pool'.
+func NewBufferPool(baseline int) *BufferPool {
+	if baseline <= 0 {
+		panic("baseline can't be <= 0")
+	}
+	p := &BufferPool{
+		baseline0: baseline,
+		baseline:  [...]int{baseline / 4, baseline / 2, baseline * 2, baseline * 4},
+		closeC:    make(chan struct{}, 1),
+	}
+	for i, cap := range []int{2, 2, 4, 4, 2, 1} {
+		p.pool[i] = make(chan []byte, cap)
+	}
+	go p.drain()
+	return p
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/crc32.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/crc32.go
new file mode 100644
index 0000000000..631c9d6109
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util/crc32.go
@@ -0,0 +1,30 @@
+// Copyright 2011 The LevelDB-Go Authors. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package util
+
+import (
+	"hash/crc32"
+)
+
+var table = crc32.MakeTable(crc32.Castagnoli)
+
+// CRC is a CRC-32 checksum computed using Castagnoli's polynomial.
+type CRC uint32
+
+// NewCRC creates a new crc based on the given bytes.
+func NewCRC(b []byte) CRC {
+	return CRC(0).Update(b)
+}
+
+// Update updates the crc with the given bytes.
+func (c CRC) Update(b []byte) CRC {
+	return CRC(crc32.Update(uint32(c), table, b))
+}
+
+// Value returns a masked crc.
+func (c CRC) Value() uint32 {
+	return uint32(c>>15|c<<17) + 0xa282ead8
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/hash.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/hash.go
new file mode 100644
index 0000000000..7f3fa4e2c7
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util/hash.go
@@ -0,0 +1,48 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package util
+
+import (
+	"encoding/binary"
+)
+
+// Hash return hash of the given data.
+func Hash(data []byte, seed uint32) uint32 {
+	// Similar to murmur hash
+	const (
+		m = uint32(0xc6a4a793)
+		r = uint32(24)
+	)
+	var (
+		h = seed ^ (uint32(len(data)) * m)
+		i int
+	)
+
+	for n := len(data) - len(data)%4; i < n; i += 4 {
+		h += binary.LittleEndian.Uint32(data[i:])
+		h *= m
+		h ^= (h >> 16)
+	}
+
+	switch len(data) - i {
+	default:
+		panic("not reached")
+	case 3:
+		h += uint32(data[i+2]) << 16
+		fallthrough
+	case 2:
+		h += uint32(data[i+1]) << 8
+		fallthrough
+	case 1:
+		h += uint32(data[i])
+		h *= m
+		h ^= (h >> r)
+	case 0:
+	}
+
+	return h
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/range.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/range.go
new file mode 100644
index 0000000000..85159583d2
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util/range.go
@@ -0,0 +1,32 @@
+// Copyright (c) 2014, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package util
+
+// Range is a key range.
+type Range struct {
+	// Start of the key range, include in the range.
+	Start []byte
+
+	// Limit of the key range, not include in the range.
+	Limit []byte
+}
+
+// BytesPrefix returns key range that satisfy the given prefix.
+// This only applicable for the standard 'bytes comparer'.
+func BytesPrefix(prefix []byte) *Range {
+	var limit []byte
+	for i := len(prefix) - 1; i >= 0; i-- {
+		c := prefix[i]
+		if c < 0xff {
+			limit = make([]byte, i+1)
+			copy(limit, prefix)
+			limit[i] = c + 1
+			break
+		}
+	}
+	return &Range{prefix, limit}
+}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/util/util.go b/vendor/github.com/syndtr/goleveldb/leveldb/util/util.go
new file mode 100644
index 0000000000..80614afc58
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/util/util.go
@@ -0,0 +1,73 @@
+// Copyright (c) 2013, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Package util provides utilities used throughout leveldb.
+package util
+
+import (
+	"errors"
+)
+
+var (
+	ErrReleased    = errors.New("leveldb: resource already relesed")
+	ErrHasReleaser = errors.New("leveldb: releaser already defined")
+)
+
+// Releaser is the interface that wraps the basic Release method.
+type Releaser interface {
+	// Release releases associated resources. Release should always success
+	// and can be called multiple times without causing error.
+	Release()
+}
+
+// ReleaseSetter is the interface that wraps the basic SetReleaser method.
+type ReleaseSetter interface {
+	// SetReleaser associates the given releaser to the resources. The
+	// releaser will be called once coresponding resources released.
+	// Calling SetReleaser with nil will clear the releaser.
+	//
+	// This will panic if a releaser already present or coresponding
+	// resource is already released. Releaser should be cleared first
+	// before assigned a new one.
+	SetReleaser(releaser Releaser)
+}
+
+// BasicReleaser provides basic implementation of Releaser and ReleaseSetter.
+type BasicReleaser struct {
+	releaser Releaser
+	released bool
+}
+
+// Released returns whether Release method already called.
+func (r *BasicReleaser) Released() bool {
+	return r.released
+}
+
+// Release implements Releaser.Release.
+func (r *BasicReleaser) Release() {
+	if !r.released {
+		if r.releaser != nil {
+			r.releaser.Release()
+			r.releaser = nil
+		}
+		r.released = true
+	}
+}
+
+// SetReleaser implements ReleaseSetter.SetReleaser.
+func (r *BasicReleaser) SetReleaser(releaser Releaser) {
+	if r.released {
+		panic(ErrReleased)
+	}
+	if r.releaser != nil && releaser != nil {
+		panic(ErrHasReleaser)
+	}
+	r.releaser = releaser
+}
+
+type NoopReleaser struct{}
+
+func (NoopReleaser) Release() {}
diff --git a/vendor/github.com/syndtr/goleveldb/leveldb/version.go b/vendor/github.com/syndtr/goleveldb/leveldb/version.go
new file mode 100644
index 0000000000..73f272af5f
--- /dev/null
+++ b/vendor/github.com/syndtr/goleveldb/leveldb/version.go
@@ -0,0 +1,528 @@
+// Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
+// All rights reserved.
+//
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package leveldb
+
+import (
+	"fmt"
+	"sync/atomic"
+	"unsafe"
+
+	"github.com/syndtr/goleveldb/leveldb/iterator"
+	"github.com/syndtr/goleveldb/leveldb/opt"
+	"github.com/syndtr/goleveldb/leveldb/util"
+)
+
+type tSet struct {
+	level int
+	table *tFile
+}
+
+type version struct {
+	s *session
+
+	levels []tFiles
+
+	// Level that should be compacted next and its compaction score.
+	// Score < 1 means compaction is not strictly needed. These fields
+	// are initialized by computeCompaction()
+	cLevel int
+	cScore float64
+
+	cSeek unsafe.Pointer
+
+	closing  bool
+	ref      int
+	released bool
+}
+
+func newVersion(s *session) *version {
+	return &version{s: s}
+}
+
+func (v *version) incref() {
+	if v.released {
+		panic("already released")
+	}
+
+	v.ref++
+	if v.ref == 1 {
+		// Incr file ref.
+		for _, tt := range v.levels {
+			for _, t := range tt {
+				v.s.addFileRef(t.fd, 1)
+			}
+		}
+	}
+}
+
+func (v *version) releaseNB() {
+	v.ref--
+	if v.ref > 0 {
+		return
+	} else if v.ref < 0 {
+		panic("negative version ref")
+	}
+
+	for _, tt := range v.levels {
+		for _, t := range tt {
+			if v.s.addFileRef(t.fd, -1) == 0 {
+				v.s.tops.remove(t)
+			}
+		}
+	}
+
+	v.released = true
+}
+
+func (v *version) release() {
+	v.s.vmu.Lock()
+	v.releaseNB()
+	v.s.vmu.Unlock()
+}
+
+func (v *version) walkOverlapping(aux tFiles, ikey internalKey, f func(level int, t *tFile) bool, lf func(level int) bool) {
+	ukey := ikey.ukey()
+
+	// Aux level.
+	if aux != nil {
+		for _, t := range aux {
+			if t.overlaps(v.s.icmp, ukey, ukey) {
+				if !f(-1, t) {
+					return
+				}
+			}
+		}
+
+		if lf != nil && !lf(-1) {
+			return
+		}
+	}
+
+	// Walk tables level-by-level.
+	for level, tables := range v.levels {
+		if len(tables) == 0 {
+			continue
+		}
+
+		if level == 0 {
+			// Level-0 files may overlap each other. Find all files that
+			// overlap ukey.
+			for _, t := range tables {
+				if t.overlaps(v.s.icmp, ukey, ukey) {
+					if !f(level, t) {
+						return
+					}
+				}
+			}
+		} else {
+			if i := tables.searchMax(v.s.icmp, ikey); i < len(tables) {
+				t := tables[i]
+				if v.s.icmp.uCompare(ukey, t.imin.ukey()) >= 0 {
+					if !f(level, t) {
+						return
+					}
+				}
+			}
+		}
+
+		if lf != nil && !lf(level) {
+			return
+		}
+	}
+}
+
+func (v *version) get(aux tFiles, ikey internalKey, ro *opt.ReadOptions, noValue bool) (value []byte, tcomp bool, err error) {
+	if v.closing {
+		return nil, false, ErrClosed
+	}
+
+	ukey := ikey.ukey()
+
+	var (
+		tset  *tSet
+		tseek bool
+
+		// Level-0.
+		zfound bool
+		zseq   uint64
+		zkt    keyType
+		zval   []byte
+	)
+
+	err = ErrNotFound
+
+	// Since entries never hop across level, finding key/value
+	// in smaller level make later levels irrelevant.
+	v.walkOverlapping(aux, ikey, func(level int, t *tFile) bool {
+		if level >= 0 && !tseek {
+			if tset == nil {
+				tset = &tSet{level, t}
+			} else {
+				tseek = true
+			}
+		}
+
+		var (
+			fikey, fval []byte
+			ferr        error
+		)
+		if noValue {
+			fikey, ferr = v.s.tops.findKey(t, ikey, ro)
+		} else {
+			fikey, fval, ferr = v.s.tops.find(t, ikey, ro)
+		}
+
+		switch ferr {
+		case nil:
+		case ErrNotFound:
+			return true
+		default:
+			err = ferr
+			return false
+		}
+
+		if fukey, fseq, fkt, fkerr := parseInternalKey(fikey); fkerr == nil {
+			if v.s.icmp.uCompare(ukey, fukey) == 0 {
+				// Level <= 0 may overlaps each-other.
+				if level <= 0 {
+					if fseq >= zseq {
+						zfound = true
+						zseq = fseq
+						zkt = fkt
+						zval = fval
+					}
+				} else {
+					switch fkt {
+					case keyTypeVal:
+						value = fval
+						err = nil
+					case keyTypeDel:
+					default:
+						panic("leveldb: invalid internalKey type")
+					}
+					return false
+				}
+			}
+		} else {
+			err = fkerr
+			return false
+		}
+
+		return true
+	}, func(level int) bool {
+		if zfound {
+			switch zkt {
+			case keyTypeVal:
+				value = zval
+				err = nil
+			case keyTypeDel:
+			default:
+				panic("leveldb: invalid internalKey type")
+			}
+			return false
+		}
+
+		return true
+	})
+
+	if tseek && tset.table.consumeSeek() <= 0 {
+		tcomp = atomic.CompareAndSwapPointer(&v.cSeek, nil, unsafe.Pointer(tset))
+	}
+
+	return
+}
+
+func (v *version) sampleSeek(ikey internalKey) (tcomp bool) {
+	var tset *tSet
+
+	v.walkOverlapping(nil, ikey, func(level int, t *tFile) bool {
+		if tset == nil {
+			tset = &tSet{level, t}
+			return true
+		}
+		if tset.table.consumeSeek() <= 0 {
+			tcomp = atomic.CompareAndSwapPointer(&v.cSeek, nil, unsafe.Pointer(tset))
+		}
+		return false
+	}, nil)
+
+	return
+}
+
+func (v *version) getIterators(slice *util.Range, ro *opt.ReadOptions) (its []iterator.Iterator) {
+	strict := opt.GetStrict(v.s.o.Options, ro, opt.StrictReader)
+	for level, tables := range v.levels {
+		if level == 0 {
+			// Merge all level zero files together since they may overlap.
+			for _, t := range tables {
+				its = append(its, v.s.tops.newIterator(t, slice, ro))
+			}
+		} else if len(tables) != 0 {
+			its = append(its, iterator.NewIndexedIterator(tables.newIndexIterator(v.s.tops, v.s.icmp, slice, ro), strict))
+		}
+	}
+	return
+}
+
+func (v *version) newStaging() *versionStaging {
+	return &versionStaging{base: v}
+}
+
+// Spawn a new version based on this version.
+func (v *version) spawn(r *sessionRecord) *version {
+	staging := v.newStaging()
+	staging.commit(r)
+	return staging.finish()
+}
+
+func (v *version) fillRecord(r *sessionRecord) {
+	for level, tables := range v.levels {
+		for _, t := range tables {
+			r.addTableFile(level, t)
+		}
+	}
+}
+
+func (v *version) tLen(level int) int {
+	if level < len(v.levels) {
+		return len(v.levels[level])
+	}
+	return 0
+}
+
+func (v *version) offsetOf(ikey internalKey) (n int64, err error) {
+	for level, tables := range v.levels {
+		for _, t := range tables {
+			if v.s.icmp.Compare(t.imax, ikey) <= 0 {
+				// Entire file is before "ikey", so just add the file size
+				n += t.size
+			} else if v.s.icmp.Compare(t.imin, ikey) > 0 {
+				// Entire file is after "ikey", so ignore
+				if level > 0 {
+					// Files other than level 0 are sorted by meta->min, so
+					// no further files in this level will contain data for
+					// "ikey".
+					break
+				}
+			} else {
+				// "ikey" falls in the range for this table. Add the
+				// approximate offset of "ikey" within the table.
+				if m, err := v.s.tops.offsetOf(t, ikey); err == nil {
+					n += m
+				} else {
+					return 0, err
+				}
+			}
+		}
+	}
+
+	return
+}
+
+func (v *version) pickMemdbLevel(umin, umax []byte, maxLevel int) (level int) {
+	if maxLevel > 0 {
+		if len(v.levels) == 0 {
+			return maxLevel
+		}
+		if !v.levels[0].overlaps(v.s.icmp, umin, umax, true) {
+			var overlaps tFiles
+			for ; level < maxLevel; level++ {
+				if pLevel := level + 1; pLevel >= len(v.levels) {
+					return maxLevel
+				} else if v.levels[pLevel].overlaps(v.s.icmp, umin, umax, false) {
+					break
+				}
+				if gpLevel := level + 2; gpLevel < len(v.levels) {
+					overlaps = v.levels[gpLevel].getOverlaps(overlaps, v.s.icmp, umin, umax, false)
+					if overlaps.size() > int64(v.s.o.GetCompactionGPOverlaps(level)) {
+						break
+					}
+				}
+			}
+		}
+	}
+	return
+}
+
+func (v *version) computeCompaction() {
+	// Precomputed best level for next compaction
+	bestLevel := int(-1)
+	bestScore := float64(-1)
+
+	statFiles := make([]int, len(v.levels))
+	statSizes := make([]string, len(v.levels))
+	statScore := make([]string, len(v.levels))
+	statTotSize := int64(0)
+
+	for level, tables := range v.levels {
+		var score float64
+		size := tables.size()
+		if level == 0 {
+			// We treat level-0 specially by bounding the number of files
+			// instead of number of bytes for two reasons:
+			//
+			// (1) With larger write-buffer sizes, it is nice not to do too
+			// many level-0 compaction.
+			//
+			// (2) The files in level-0 are merged on every read and
+			// therefore we wish to avoid too many files when the individual
+			// file size is small (perhaps because of a small write-buffer
+			// setting, or very high compression ratios, or lots of
+			// overwrites/deletions).
+			score = float64(len(tables)) / float64(v.s.o.GetCompactionL0Trigger())
+		} else {
+			score = float64(size) / float64(v.s.o.GetCompactionTotalSize(level))
+		}
+
+		if score > bestScore {
+			bestLevel = level
+			bestScore = score
+		}
+
+		statFiles[level] = len(tables)
+		statSizes[level] = shortenb(int(size))
+		statScore[level] = fmt.Sprintf("%.2f", score)
+		statTotSize += size
+	}
+
+	v.cLevel = bestLevel
+	v.cScore = bestScore
+
+	v.s.logf("version@stat F·%v S·%s%v Sc·%v", statFiles, shortenb(int(statTotSize)), statSizes, statScore)
+}
+
+func (v *version) needCompaction() bool {
+	return v.cScore >= 1 || atomic.LoadPointer(&v.cSeek) != nil
+}
+
+type tablesScratch struct {
+	added   map[int64]atRecord
+	deleted map[int64]struct{}
+}
+
+type versionStaging struct {
+	base   *version
+	levels []tablesScratch
+}
+
+func (p *versionStaging) getScratch(level int) *tablesScratch {
+	if level >= len(p.levels) {
+		newLevels := make([]tablesScratch, level+1)
+		copy(newLevels, p.levels)
+		p.levels = newLevels
+	}
+	return &(p.levels[level])
+}
+
+func (p *versionStaging) commit(r *sessionRecord) {
+	// Deleted tables.
+	for _, r := range r.deletedTables {
+		scratch := p.getScratch(r.level)
+		if r.level < len(p.base.levels) && len(p.base.levels[r.level]) > 0 {
+			if scratch.deleted == nil {
+				scratch.deleted = make(map[int64]struct{})
+			}
+			scratch.deleted[r.num] = struct{}{}
+		}
+		if scratch.added != nil {
+			delete(scratch.added, r.num)
+		}
+	}
+
+	// New tables.
+	for _, r := range r.addedTables {
+		scratch := p.getScratch(r.level)
+		if scratch.added == nil {
+			scratch.added = make(map[int64]atRecord)
+		}
+		scratch.added[r.num] = r
+		if scratch.deleted != nil {
+			delete(scratch.deleted, r.num)
+		}
+	}
+}
+
+func (p *versionStaging) finish() *version {
+	// Build new version.
+	nv := newVersion(p.base.s)
+	numLevel := len(p.levels)
+	if len(p.base.levels) > numLevel {
+		numLevel = len(p.base.levels)
+	}
+	nv.levels = make([]tFiles, numLevel)
+	for level := 0; level < numLevel; level++ {
+		var baseTabels tFiles
+		if level < len(p.base.levels) {
+			baseTabels = p.base.levels[level]
+		}
+
+		if level < len(p.levels) {
+			scratch := p.levels[level]
+
+			var nt tFiles
+			// Prealloc list if possible.
+			if n := len(baseTabels) + len(scratch.added) - len(scratch.deleted); n > 0 {
+				nt = make(tFiles, 0, n)
+			}
+
+			// Base tables.
+			for _, t := range baseTabels {
+				if _, ok := scratch.deleted[t.fd.Num]; ok {
+					continue
+				}
+				if _, ok := scratch.added[t.fd.Num]; ok {
+					continue
+				}
+				nt = append(nt, t)
+			}
+
+			// New tables.
+			for _, r := range scratch.added {
+				nt = append(nt, tableFileFromRecord(r))
+			}
+
+			if len(nt) != 0 {
+				// Sort tables.
+				if level == 0 {
+					nt.sortByNum()
+				} else {
+					nt.sortByKey(p.base.s.icmp)
+				}
+
+				nv.levels[level] = nt
+			}
+		} else {
+			nv.levels[level] = baseTabels
+		}
+	}
+
+	// Trim levels.
+	n := len(nv.levels)
+	for ; n > 0 && nv.levels[n-1] == nil; n-- {
+	}
+	nv.levels = nv.levels[:n]
+
+	// Compute compaction score for new version.
+	nv.computeCompaction()
+
+	return nv
+}
+
+type versionReleaser struct {
+	v    *version
+	once bool
+}
+
+func (vr *versionReleaser) Release() {
+	v := vr.v
+	v.s.vmu.Lock()
+	if !vr.once {
+		v.releaseNB()
+		vr.once = true
+	}
+	v.s.vmu.Unlock()
+}