Decrease the num_stars when deleting a repo (#11954)

* Decrease the  num_stars when deleting a repo

fix #11949

Signed-off-by: a1012112796 <1012112796@qq.com>

* Add migration

* use batch

* Apply suggestions from code review

Co-authored-by: Lauris BH <lauris@nix.lv>

* fix lint

* fix lint

* fix ci

* fix ci2

* add doctor

* duplicate code

* fix migration

* fix some nits

* add start

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: zeripath <art27@cantab.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

2 files changed, 54 insertions, 0 deletions

diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 6cc80249a3..d205794e1f 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -218,6 +218,8 @@ var migrations = []Migration{
 	NewMigration("Add KeepActivityPrivate to User table", addKeepActivityPrivateUserColumn),
 	// v142 -> v143
 	NewMigration("Ensure Repository.IsArchived is not null", setIsArchivedToFalse),
+	// v143 -> v144
+	NewMigration("recalculate Stars number for all user", recalculateStars),
 }
 
 // GetCurrentDBVersion returns the current db version
diff --git a/models/migrations/v143.go b/models/migrations/v143.go
new file mode 100644
index 0000000000..93237ebfcd
--- /dev/null
+++ b/models/migrations/v143.go
@@ -0,0 +1,52 @@
+// Copyright 2020 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 (
+	"code.gitea.io/gitea/modules/log"
+
+	"xorm.io/xorm"
+)
+
+func recalculateStars(x *xorm.Engine) (err error) {
+	// because of issue https://github.com/go-gitea/gitea/issues/11949,
+	// recalculate Stars number for all users to fully fix it.
+
+	type User struct {
+		ID int64 `xorm:"pk autoincr"`
+	}
+
+	const batchSize = 100
+	sess := x.NewSession()
+	defer sess.Close()
+
+	for start := 0; ; start += batchSize {
+		users := make([]User, 0, batchSize)
+		if err = sess.Limit(batchSize, start).Where("type = ?", 0).Cols("id").Find(&users); err != nil {
+			return
+		}
+		if len(users) == 0 {
+			break
+		}
+
+		if err = sess.Begin(); err != nil {
+			return
+		}
+
+		for _, user := range users {
+			if _, err = sess.Exec("UPDATE `user` SET num_stars=(SELECT COUNT(*) FROM `star` WHERE uid=?) WHERE id=?", user.ID, user.ID); err != nil {
+				return
+			}
+		}
+
+		if err = sess.Commit(); err != nil {
+			return
+		}
+	}
+
+	log.Debug("recalculate Stars number for all user finished")
+
+	return
+}