lightning/backend/local: fix buildIndexDupTasks (#44442) (#47894)

close #44439

Author: ti-chi-bot

br/pkg/lightning/backend/local/duplicate.go

@@ -635,8 +635,9 @@ func (m *DupeDetector) buildIndexDupTasks() ([]dupTask, error) {
 			tid := tablecodec.DecodeTableID(ranges[0].StartKey)
 			for _, r := range ranges {
 				tasks = append(tasks, dupTask{
-					KeyRange: r,
-					tableID:  tid,
+					KeyRange:  r,
+					tableID:   tid,
+					indexInfo: indexInfo,
 				})
 			}
 		})

ddl/ingest/backend.go

@@ -224,8 +224,11 @@ func (bc *litBackendCtx) Flush(indexID int64, mode FlushMode) (flushed, imported
 	return true, true, nil
 }
 
+// ForceSyncFlagForTest is a flag to force sync only for test.
+var ForceSyncFlagForTest = false
+
 func (bc *litBackendCtx) ShouldSync(mode FlushMode) (shouldFlush bool, shouldImport bool) {
-	if mode == FlushModeForceGlobal {
+	if mode == FlushModeForceGlobal || ForceSyncFlagForTest {
 		return true, true
 	}
 	if mode == FlushModeForceLocal {

tests/realtikvtest/addindextest/integration_test.go

@@ -536,3 +536,22 @@ func TestAddIndexPreCheckFailed(t *testing.T) {
 	tk.MustGetErrMsg("alter table t add index idx(b);", "[ddl:8256]Check ingest environment failed: mock error")
 	require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/ddl/ingest/mockIngestCheckEnvFailed"))
 }
+
+func TestAddIndexRemoteDuplicateCheck(t *testing.T) {
+	store := realtikvtest.CreateMockStoreAndSetup(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("drop database if exists addindexlit;")
+	tk.MustExec("create database addindexlit;")
+	tk.MustExec("use addindexlit;")
+	tk.MustExec(`set global tidb_ddl_enable_fast_reorg=on;`)
+	tk.MustExec("set global tidb_ddl_reorg_worker_cnt=1;")
+
+	tk.MustExec("create table t(id int primary key, b int, k int);")
+	tk.MustQuery("split table t by (30000);").Check(testkit.Rows("1 1"))
+	tk.MustExec("insert into t values(1, 1, 1);")
+	tk.MustExec("insert into t values(100000, 1, 1);")
+
+	ingest.ForceSyncFlagForTest = true
+	tk.MustGetErrCode("alter table t add unique index idx(b);", errno.ErrDupEntry)
+	ingest.ForceSyncFlagForTest = false
+}