From 72a4ef2b45df781f4c214515e576d46427d272ea 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/importer/import.go       | 7 +++----
 br/pkg/lightning/importer/table_import.go | 2 --
 2 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/br/pkg/lightning/importer/import.go b/br/pkg/lightning/importer/import.go
index 0fbb7f74205c4..b5cd1262fa98b 100644
--- a/br/pkg/lightning/importer/import.go
+++ b/br/pkg/lightning/importer/import.go
@@ -208,10 +208,9 @@ type Controller struct {
 	db            *sql.DB
 	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/importer/table_import.go b/br/pkg/lightning/importer/table_import.go
index c1da1972b8c1f..4371dacd1ce29 100644
--- a/br/pkg/lightning/importer/table_import.go
+++ b/br/pkg/lightning/importer/table_import.go
@@ -896,7 +896,6 @@ func (tr *TableImporter) postProcess(
 
 	// alter table set auto_increment
 	if cp.Status < checkpoints.CheckpointStatusAlteredAutoInc {
-		rc.alterTableLock.Lock()
 		tblInfo := tr.tableInfo.Core
 		var err error
 		if tblInfo.ContainsAutoRandomBits() {
@@ -921,7 +920,6 @@ func (tr *TableImporter) postProcess(
 				err = common.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