From 5ac97e0cab77f1d4d0c07d65e4e4fed793d15a2c Mon Sep 17 00:00:00 2001
From: ywqzzy <592838129@qq.com>
Date: Fri, 9 Jun 2023 10:25:46 +0800
Subject: [PATCH 1/2] fix

---
 ddl/ddl.go | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/ddl/ddl.go b/ddl/ddl.go
index c9ba3a768a577..e4e84ca1958e3 100644
--- a/ddl/ddl.go
+++ b/ddl/ddl.go
@@ -826,6 +826,8 @@ func (d *ddl) DisableDDL() error {
 
 // GetNextDDLSeqNum return the next DDL seq num.
 func (d *ddl) GetNextDDLSeqNum() (uint64, error) {
+	d.ddlSeqNumMu.Lock()
+	defer d.ddlSeqNumMu.Unlock()
 	var count uint64
 	ctx := kv.WithInternalSourceType(d.ctx, kv.InternalTxnDDL)
 	err := kv.RunInNewTxn(ctx, d.store, true, func(ctx context.Context, txn kv.Transaction) error {

From 77528feb0606b8a91fde4dcd3e61a4775970bc71 Mon Sep 17 00:00:00 2001
From: ywqzzy <592838129@qq.com>
Date: Fri, 9 Jun 2023 10:34:21 +0800
Subject: [PATCH 2/2] refine

---
 ddl/ddl.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/ddl/ddl.go b/ddl/ddl.go
index e4e84ca1958e3..28d15245ab3d8 100644
--- a/ddl/ddl.go
+++ b/ddl/ddl.go
@@ -755,6 +755,8 @@ func (d *ddl) Start(ctxPool *pools.ResourcePool) error {
 	d.sessPool = sess.NewSessionPool(ctxPool, d.store)
 	d.ownerManager.SetBeOwnerHook(func() {
 		var err error
+		d.ddlSeqNumMu.Lock()
+		defer d.ddlSeqNumMu.Unlock()
 		d.ddlSeqNumMu.seqNum, err = d.GetNextDDLSeqNum()
 		if err != nil {
 			logutil.BgLogger().Error("error when getting the ddl history count", zap.Error(err))
@@ -826,8 +828,6 @@ func (d *ddl) DisableDDL() error {
 
 // GetNextDDLSeqNum return the next DDL seq num.
 func (d *ddl) GetNextDDLSeqNum() (uint64, error) {
-	d.ddlSeqNumMu.Lock()
-	defer d.ddlSeqNumMu.Unlock()
 	var count uint64
 	ctx := kv.WithInternalSourceType(d.ctx, kv.InternalTxnDDL)
 	err := kv.RunInNewTxn(ctx, d.store, true, func(ctx context.Context, txn kv.Transaction) error {