add debug information

Signed-off-by: Yang Keao <[email protected]>

Author: YangKeao

ddl/db_partition_test.go

@@ -2514,19 +2514,22 @@ func TestExchangePartitionTableCompatiable(t *testing.T) {
 }
 
 func TestExchangePartitionMultiTable(t *testing.T) {
+	logutil.BgLogger().Info("mdl related variable status before bootstrap", zap.Bool("EnableMDL", variable.EnableMDL.Load()), zap.Bool("EnableConcurrentDDL", variable.EnableConcurrentDDL.Load()))
 	store := testkit.CreateMockStore(t)
 	tk1 := testkit.NewTestKit(t, store)
+	logutil.BgLogger().Info("mdl related variable status after bootstrap", zap.Bool("EnableMDL", variable.EnableMDL.Load()), zap.Bool("EnableConcurrentDDL", variable.EnableConcurrentDDL.Load()))
 
 	dbName := "ExchangeMultiTable"
 	tk1.MustExec(`create schema ` + dbName)
 	tk1.MustExec(`use ` + dbName)
-	tk1.MustExec(`set @@global.tidb_enable_metadata_lock = 1`)
+	tk1.MustExec(`set global tidb_enable_metadata_lock = 'ON'`)
 	tk1.MustExec(`CREATE TABLE t1 (a int)`)
 	tk1.MustExec(`CREATE TABLE t2 (a int)`)
 	tk1.MustExec(`CREATE TABLE tp (a int) partition by hash(a) partitions 3`)
 	tk1.MustExec(`insert into t1 values (0)`)
 	tk1.MustExec(`insert into t2 values (3)`)
 	tk1.MustExec(`insert into tp values (6)`)
+	logutil.BgLogger().Info("mdl related variable status after inserting rows", zap.Bool("EnableMDL", variable.EnableMDL.Load()), zap.Bool("EnableConcurrentDDL", variable.EnableConcurrentDDL.Load()))
 
 	tk2 := testkit.NewTestKit(t, store)
 	tk2.MustExec(`use ` + dbName)

ddl/ddl.go

@@ -1229,6 +1229,7 @@ func (d *ddl) SwitchMDL(enable bool) error {
 	ctx, cancel := context.WithTimeout(context.Background(), time.Second*30)
 	defer cancel()
 
+	logutil.BgLogger().Info("Switch EnableMDL 1", zap.Bool("arg", enable), zap.Bool("value", variable.EnableMDL.Load()))
 	// Disable MDL for test.
 	if enable && !variable.DefTiDBEnableConcurrentDDL {
 		sql := fmt.Sprintf("UPDATE HIGH_PRIORITY %[1]s.%[2]s SET VARIABLE_VALUE = %[4]d WHERE VARIABLE_NAME = '%[3]s'",
@@ -1247,6 +1248,7 @@ func (d *ddl) SwitchMDL(enable bool) error {
 		return nil
 	}
 
+	logutil.BgLogger().Info("Switch EnableMDL 2", zap.Bool("arg", enable), zap.Bool("value", variable.EnableMDL.Load()))
 	isEnableBefore := variable.EnableMDL.Load()
 	if isEnableBefore == enable {
 		return nil
@@ -1268,7 +1270,10 @@ func (d *ddl) SwitchMDL(enable bool) error {
 		return errors.New("please wait for all jobs done")
 	}
 
+	logutil.BgLogger().Info("Switch EnableMDL 3", zap.Bool("arg", enable), zap.Bool("value", variable.EnableMDL.Load()))
 	variable.EnableMDL.Store(enable)
+	logutil.BgLogger().Info("Switch EnableMDL 4", zap.Bool("arg", enable), zap.Bool("value", variable.EnableMDL.Load()))
+
 	err = kv.RunInNewTxn(kv.WithInternalSourceType(context.Background(), kv.InternalTxnDDL), d.store, true, func(ctx context.Context, txn kv.Transaction) error {
 		m := meta.NewMeta(txn)
 		oldEnable, _, err := m.GetMetadataLock()

sessionctx/variable/BUILD.bazel

@@ -67,6 +67,7 @@ go_library(
         "@org_golang_x_exp//maps",
         "@org_golang_x_exp//slices",
         "@org_uber_go_atomic//:atomic",
+        "@org_uber_go_zap//:zap",
     ],
 )
 

sessionctx/variable/sysvar.go

@@ -48,6 +48,7 @@ import (
 	tikvcfg "github.com/tikv/client-go/v2/config"
 	tikvstore "github.com/tikv/client-go/v2/kv"
 	atomic2 "go.uber.org/atomic"
+	"go.uber.org/zap"
 )
 
 // All system variables declared here are ordered by their scopes, which follow the order of scopes below:
@@ -1114,7 +1115,9 @@ var defaultSysVars = []*SysVar{
 		return BoolToOnOff(EnableConcurrentDDL.Load()), nil
 	}},
 	{Scope: ScopeGlobal, Name: TiDBEnableMDL, Value: BoolToOnOff(DefTiDBEnableMDL), Type: TypeBool, SetGlobal: func(_ context.Context, vars *SessionVars, val string) error {
+		logutil.BgLogger().Info("mdl related variable status in setting status", zap.Bool("EnableMDL", EnableMDL.Load()), zap.Bool("EnableConcurrentDDL", EnableConcurrentDDL.Load()))
 		if EnableMDL.Load() != TiDBOptOn(val) {
+			logutil.BgLogger().Info("Switch EnableMDL", zap.Bool("val", TiDBOptOn(val)))
 			err := SwitchMDL(TiDBOptOn(val))
 			if err != nil {
 				return err