From c45d1e95e91a6d15fb52648f6d40155025b2b9b2 Mon Sep 17 00:00:00 2001
From: D3Hunter <jujj603@gmail.com>
Date: Fri, 5 Jan 2024 13:47:17 +0800
Subject: [PATCH] lightning: remove alter table lock (#50074)

close pingcap/tidb#50105
---
 br/pkg/lightning/restore/restore.go       | 7 +++----
 br/pkg/lightning/restore/table_restore.go | 2 --
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/br/pkg/lightning/restore/restore.go b/br/pkg/lightning/restore/restore.go
index 6665bbecf0a4b..be5446f66d1f2 100644
--- a/br/pkg/lightning/restore/restore.go
+++ b/br/pkg/lightning/restore/restore.go
@@ -209,10 +209,9 @@ type Controller struct {
 	tidbGlue      glue.Glue
 	pdCli         pd.Client
 
-	alterTableLock sync.Mutex
-	sysVars        map[string]string
-	tls            *common.TLS
-	checkTemplate  Template
+	sysVars       map[string]string
+	tls           *common.TLS
+	checkTemplate Template
 
 	errorSummaries errorSummaries
 
diff --git a/br/pkg/lightning/restore/table_restore.go b/br/pkg/lightning/restore/table_restore.go
index d0afbc4cfac04..3d0c2a8602b76 100644
--- a/br/pkg/lightning/restore/table_restore.go
+++ b/br/pkg/lightning/restore/table_restore.go
@@ -752,7 +752,6 @@ func (tr *TableRestore) postProcess(
 
 	// 3. alter table set auto_increment
 	if cp.Status < checkpoints.CheckpointStatusAlteredAutoInc {
-		rc.alterTableLock.Lock()
 		tblInfo := tr.tableInfo.Core
 		var err error
 		if tblInfo.ContainsAutoRandomBits() {
@@ -777,7 +776,6 @@ func (tr *TableRestore) postProcess(
 				err = rebaseGlobalAutoID(ctx, adjustIDBase(newBase), tr, tr.dbInfo.ID, tr.tableInfo.Core)
 			}
 		}
-		rc.alterTableLock.Unlock()
 		saveCpErr := rc.saveStatusCheckpoint(ctx, tr.tableName, checkpoints.WholeTableEngineID, err, checkpoints.CheckpointStatusAlteredAutoInc)
 		if err = firstErr(err, saveCpErr); err != nil {
 			return false, err