session: enable foreign_key_checks/tidb_enable_foreign_key by default when upgrade

session/bootstrap.go

@@ -794,11 +794,15 @@ const (
 	version111 = 111
 	// version112 modifies the view tidb_mdl_view
 	version112 = 112
+	// version113 modifies the following global variables default value:
+	// - foreign_key_checks: off -> on
+	// - tidb_enable_foreign_key: off -> on
+	version113 = 113
 )
 
 // currentBootstrapVersion is defined as a variable, so we can modify its value for testing.
 // please make sure this is the largest version
-var currentBootstrapVersion int64 = version112
+var currentBootstrapVersion int64 = version113
 
 // DDL owner key's expired time is ManagerSessionTTL seconds, we should wait the time and give more time to have a chance to finish it.
 var internalSQLTimeout = owner.ManagerSessionTTL + 15
@@ -918,6 +922,7 @@ var (
 		upgradeToVer110,
 		upgradeToVer111,
 		upgradeToVer112,
+		upgradeToVer113,
 	}
 )
 
@@ -2285,6 +2290,15 @@ func upgradeToVer112(s Session, ver int64) {
 	doReentrantDDL(s, CreateMDLView)
 }
 
+func upgradeToVer113(s Session, ver int64) {
+	if ver >= version113 {
+		return
+	}
+
+	mustExecute(s, "REPLACE HIGH_PRIORITY INTO %n.%n VALUES (%?, %?);", mysql.SystemDB, mysql.GlobalVariablesTable, variable.ForeignKeyChecks, variable.On)
+	mustExecute(s, "REPLACE HIGH_PRIORITY INTO %n.%n VALUES (%?, %?);", mysql.SystemDB, mysql.GlobalVariablesTable, variable.TiDBEnableForeignKey, variable.On)
+}
+
 func writeOOMAction(s Session) {
 	comment := "oom-action is `log` by default in v3.0.x, `cancel` by default in v4.0.11+"
 	mustExecute(s, `INSERT HIGH_PRIORITY INTO %n.%n VALUES (%?, %?, %?) ON DUPLICATE KEY UPDATE VARIABLE_VALUE= %?`,

session/bootstrap_test.go

@@ -1417,3 +1417,64 @@ func TestTiDBGCAwareUpgradeFrom630To650(t *testing.T) {
 	require.Equal(t, 2, row.Len())
 	require.Equal(t, "0", row.GetString(1))
 }
+
+func TestTiDBGlobalVariablesDefaultValueUpgradeFrom630To660(t *testing.T) {
+	ctx := context.Background()
+	store, _ := createStoreAndBootstrap(t)
+	defer func() { require.NoError(t, store.Close()) }()
+
+	// upgrade from 6.3.0 to 6.6.0.
+	ver630 := version93
+	seV630 := createSessionAndSetID(t, store)
+	txn, err := store.Begin()
+	require.NoError(t, err)
+	m := meta.NewMeta(txn)
+	err = m.FinishBootstrap(int64(ver630))
+	require.NoError(t, err)
+	err = txn.Commit(context.Background())
+	require.NoError(t, err)
+	mustExec(t, seV630, fmt.Sprintf("update mysql.tidb set variable_value=%d where variable_name='tidb_server_version'", ver630))
+	mustExec(t, seV630, fmt.Sprintf("update mysql.GLOBAL_VARIABLES set variable_value='%s' where variable_name='%s'", "OFF", variable.TiDBEnableForeignKey))
+	mustExec(t, seV630, fmt.Sprintf("update mysql.GLOBAL_VARIABLES set variable_value='%s' where variable_name='%s'", "OFF", variable.ForeignKeyChecks))
+	mustExec(t, seV630, "commit")
+	unsetStoreBootstrapped(store.UUID())
+	ver, err := getBootstrapVersion(seV630)
+	require.NoError(t, err)
+	require.Equal(t, int64(ver630), ver)
+
+	// We are now in 6.3.0.
+	upgradeVars := []string{variable.TiDBEnableForeignKey, variable.ForeignKeyChecks}
+	varsValueList := []string{"OFF", "OFF"}
+	for i := range upgradeVars {
+		res := mustExecToRecodeSet(t, seV630, fmt.Sprintf("select * from mysql.GLOBAL_VARIABLES where variable_name='%s'", upgradeVars[i]))
+		chk := res.NewChunk(nil)
+		err = res.Next(ctx, chk)
+		require.NoError(t, err)
+		require.Equal(t, 1, chk.NumRows())
+		row := chk.GetRow(0)
+		require.Equal(t, 2, row.Len())
+		require.Equal(t, varsValueList[i], row.GetString(1))
+	}
+
+	// Upgrade to 6.6.0.
+	domCurVer, err := BootstrapSession(store)
+	require.NoError(t, err)
+	defer domCurVer.Close()
+	seV660 := createSessionAndSetID(t, store)
+	ver, err = getBootstrapVersion(seV660)
+	require.NoError(t, err)
+	require.Equal(t, currentBootstrapVersion, ver)
+
+	// We are now in 6.6.0.
+	varsValueList = []string{"ON", "ON"}
+	for i := range upgradeVars {
+		res := mustExecToRecodeSet(t, seV660, fmt.Sprintf("select * from mysql.GLOBAL_VARIABLES where variable_name='%s'", upgradeVars[i]))
+		chk := res.NewChunk(nil)
+		err = res.Next(ctx, chk)
+		require.NoError(t, err)
+		require.Equal(t, 1, chk.NumRows())
+		row := chk.GetRow(0)
+		require.Equal(t, 2, row.Len())
+		require.Equal(t, varsValueList[i], row.GetString(1))
+	}
+}