Fix commit status index problem (#17061)

* Fix commit status index problem

* remove unused functions

* Add fixture and test for migration

* Fix lint

* Fix fixture

* Fix lint

* Fix test

* Fix bug

* Fix bug

3 files changed, 111 insertions, 0 deletions

diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index fb6958f2da..3f90e5e74a 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -342,6 +342,8 @@ var migrations = []Migration{
 	NewMigration("Add repo id column for attachment table", addRepoIDForAttachment),
 	// v194 -> v195
 	NewMigration("Add Branch Protection Unprotected Files Column", addBranchProtectionUnprotectedFilesColumn),
+	// v196 -> v197
+	NewMigration("Add table commit_status_index", addTableCommitStatusIndex),
 }
 
 // GetCurrentDBVersion returns the current db version
diff --git a/models/migrations/v195.go b/models/migrations/v195.go
new file mode 100644
index 0000000000..06694eb57d
--- /dev/null
+++ b/models/migrations/v195.go
@@ -0,0 +1,47 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"fmt"
+
+	"xorm.io/xorm"
+)
+
+func addTableCommitStatusIndex(x *xorm.Engine) error {
+	// CommitStatusIndex represents a table for commit status index
+	type CommitStatusIndex struct {
+		ID       int64
+		RepoID   int64  `xorm:"unique(repo_sha)"`
+		SHA      string `xorm:"unique(repo_sha)"`
+		MaxIndex int64  `xorm:"index"`
+	}
+
+	if err := x.Sync2(new(CommitStatusIndex)); err != nil {
+		return fmt.Errorf("Sync2: %v", err)
+	}
+
+	sess := x.NewSession()
+	defer sess.Close()
+
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	// Remove data we're goint to rebuild
+	if _, err := sess.Table("commit_status_index").Where("1=1").Delete(&CommitStatusIndex{}); err != nil {
+		return err
+	}
+
+	// Create current data for all repositories with issues and PRs
+	if _, err := sess.Exec("INSERT INTO commit_status_index (repo_id, sha, max_index) " +
+		"SELECT max_data.repo_id, max_data.sha, max_data.max_index " +
+		"FROM ( SELECT commit_status.repo_id AS repo_id, commit_status.sha AS sha, max(commit_status.`index`) AS max_index " +
+		"FROM commit_status GROUP BY commit_status.repo_id, commit_status.sha) AS max_data"); err != nil {
+		return err
+	}
+
+	return sess.Commit()
+}
diff --git a/models/migrations/v195_test.go b/models/migrations/v195_test.go
new file mode 100644
index 0000000000..baf9cb61c2
--- /dev/null
+++ b/models/migrations/v195_test.go
@@ -0,0 +1,62 @@
+// Copyright 2021 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package migrations
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_addTableCommitStatusIndex(t *testing.T) {
+	// Create the models used in the migration
+	type CommitStatus struct {
+		ID     int64  `xorm:"pk autoincr"`
+		Index  int64  `xorm:"INDEX UNIQUE(repo_sha_index)"`
+		RepoID int64  `xorm:"INDEX UNIQUE(repo_sha_index)"`
+		SHA    string `xorm:"VARCHAR(64) NOT NULL INDEX UNIQUE(repo_sha_index)"`
+	}
+
+	// Prepare and load the testing database
+	x, deferable := prepareTestEnv(t, 0, new(CommitStatus))
+	if x == nil || t.Failed() {
+		defer deferable()
+		return
+	}
+	defer deferable()
+
+	// Run the migration
+	if err := addTableCommitStatusIndex(x); err != nil {
+		assert.NoError(t, err)
+		return
+	}
+
+	type CommitStatusIndex struct {
+		ID       int64
+		RepoID   int64  `xorm:"unique(repo_sha)"`
+		SHA      string `xorm:"unique(repo_sha)"`
+		MaxIndex int64  `xorm:"index"`
+	}
+
+	var start = 0
+	const batchSize = 1000
+	for {
+		var indexes = make([]CommitStatusIndex, 0, batchSize)
+		err := x.Table("commit_status_index").Limit(batchSize, start).Find(&indexes)
+		assert.NoError(t, err)
+
+		for _, idx := range indexes {
+			var maxIndex int
+			has, err := x.SQL("SELECT max(`index`) FROM commit_status WHERE repo_id = ? AND sha = ?", idx.RepoID, idx.SHA).Get(&maxIndex)
+			assert.NoError(t, err)
+			assert.True(t, has)
+			assert.EqualValues(t, maxIndex, idx.MaxIndex)
+		}
+		if len(indexes) < batchSize {
+			break
+		}
+		start += len(indexes)
+	}
+}