ddl: use the correct timezone to encode record for adding index (#46055)

close #46033

Author: tangenta

ddl/index_cop.go

@@ -484,7 +484,7 @@ func getRestoreData(tblInfo *model.TableInfo, targetIdx, pkIdx *model.IndexInfo,
 
 func buildDAGPB(sCtx sessionctx.Context, tblInfo *model.TableInfo, colInfos []*model.ColumnInfo) (*tipb.DAGRequest, error) {
 	dagReq := &tipb.DAGRequest{}
-	dagReq.TimeZoneName, dagReq.TimeZoneOffset = timeutil.Zone(sCtx.GetSessionVars().Location())
+	_, dagReq.TimeZoneOffset = timeutil.Zone(sCtx.GetSessionVars().Location())
 	sc := sCtx.GetSessionVars().StmtCtx
 	dagReq.Flags = sc.PushDownFlags()
 	for i := range colInfos {

ddl/ingest/BUILD.bazel

@@ -65,7 +65,7 @@ go_test(
     embed = [":ingest"],
     flaky = True,
     race = "on",
-    shard_count = 14,
+    shard_count = 15,
     deps = [
         "//config",
         "//ddl",

ddl/ingest/integration_test.go

@@ -323,3 +323,22 @@ func TestAddIndexIngestRecoverPartition(t *testing.T) {
 	tk.MustExec("alter table t add index idx(b);")
 	tk.MustExec("admin check table t;")
 }
+
+func TestAddIndexIngestTimezone(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test;")
+	defer injectMockBackendMgr(t, store)()
+
+	tk.MustExec("SET time_zone = '-06:00';")
+	tk.MustExec("create table t (`src` varchar(48),`t` timestamp,`timezone` varchar(100));")
+	tk.MustExec("insert into t values('2000-07-29 23:15:30','2000-07-29 23:15:30','-6:00');")
+	tk.MustExec("alter table t add index idx(t);")
+	tk.MustExec("admin check table t;")
+
+	tk.MustExec("alter table t drop index idx;")
+	tk.MustExec("SET time_zone = 'Asia/Shanghai';")
+	tk.MustExec("insert into t values('2000-07-29 23:15:30','2000-07-29 23:15:30', '+8:00');")
+	tk.MustExec("alter table t add index idx(t);")
+	tk.MustExec("admin check table t;")
+}