ddl: fix cleanup subtasks after cancel add index with dist-reorg

ddl/backfilling.go

@@ -109,6 +109,11 @@ type BackfillJob struct {
 	Meta            *model.BackfillMeta
 }
 
+// PrefixKeyString returns the BackfillJob's prefix key.
+func (bj *BackfillJob) PrefixKeyString() string {
+	return fmt.Sprintf("%d_%s_%d_%%", bj.JobID, hex.EncodeToString(bj.EleKey), bj.EleID)
+}
+
 // AbbrStr returns the BackfillJob's info without the Meta info.
 func (bj *BackfillJob) AbbrStr() string {
 	return fmt.Sprintf("ID:%d, JobID:%d, EleID:%d, Type:%s, State:%s, InstanceID:%s, InstanceLease:%s",

ddl/dist_owner.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/pingcap/errors"
+	"github.com/pingcap/failpoint"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/meta"
 	"github.com/pingcap/tidb/metrics"
@@ -323,7 +324,14 @@ func checkReorgJobFinished(ctx context.Context, sess *session, reorgCtxs *reorgC
 	ticker := time.NewTicker(CheckBackfillJobFinishInterval)
 	defer ticker.Stop()
 	for {
+		failpoint.Inject("MockCanceledErr", func() {
+			getReorgCtx(reorgCtxs, ddlJobID).notifyReorgCancel()
+		})
 		if getReorgCtx(reorgCtxs, ddlJobID).isReorgCanceled() {
+			err := cleanupBackfillJobs(sess, fmt.Sprintf("%d_%s_%d_%%", ddlJobID, hex.EncodeToString(currEle.TypeKey), currEle.ID))
+			if err != nil {
+				return err
+			}
 			// Job is cancelled. So it can't be done.
 			return dbterror.ErrCancelledDDLJob
 		}
@@ -366,6 +374,10 @@ func checkReorgJobFinished(ctx context.Context, sess *session, reorgCtxs *reorgC
 				}
 			}
 		case <-ctx.Done():
+			err := cleanupBackfillJobs(sess, fmt.Sprintf("%d_%s_%d_%%", ddlJobID, hex.EncodeToString(currEle.TypeKey), currEle.ID))
+			if err != nil {
+				return err
+			}
 			return ctx.Err()
 		}
 	}
@@ -428,15 +440,20 @@ func checkAndHandleInterruptedBackfillJobs(sess *session, ddlJobID, currEleID in
 		return nil
 	}
 
+	return cleanupBackfillJobs(sess, bJobs[0].PrefixKeyString())
+}
+
+func cleanupBackfillJobs(sess *session, prefixKey string) error {
+	var err error
 	for i := 0; i < retrySQLTimes; i++ {
-		err = MoveBackfillJobsToHistoryTable(sess, bJobs[0])
+		err = MoveBackfillJobsToHistoryTable(sess, prefixKey)
 		if err == nil {
-			return bJobs[0].Meta.Error
+			return nil
 		}
 		logutil.BgLogger().Info("[ddl] MoveBackfillJobsToHistoryTable failed", zap.Error(err))
 		time.Sleep(RetrySQLInterval)
 	}
-	return errors.Trace(err)
+	return err
 }
 
 func checkBackfillJobCount(sess *session, ddlJobID, currEleID int64, currEleKey []byte, pTblID int64) (backfillJobCnt int, err error) {
@@ -496,16 +513,15 @@ func GetPhysicalTableMetas(sess *session, ddlJobID, currEleID int64, currEleKey
 }
 
 // MoveBackfillJobsToHistoryTable moves backfill table jobs to the backfill history table.
-func MoveBackfillJobsToHistoryTable(sctx sessionctx.Context, bfJob *BackfillJob) error {
+func MoveBackfillJobsToHistoryTable(sctx sessionctx.Context, prefixKey string) error {
 	s, ok := sctx.(*session)
 	if !ok {
 		return errors.Errorf("sess ctx:%#v convert session failed", sctx)
 	}
 
 	return s.runInTxn(func(se *session) error {
 		// TODO: Consider batch by batch update backfill jobs and insert backfill history jobs.
-		bJobs, err := GetBackfillJobs(se, BackgroundSubtaskTable, fmt.Sprintf("task_key like \"%d_%s_%d_%%\"",
-			bfJob.JobID, hex.EncodeToString(bfJob.EleKey), bfJob.EleID), "update_backfill_job")
+		bJobs, err := GetBackfillJobs(se, BackgroundSubtaskTable, fmt.Sprintf("task_key like '%s'", prefixKey), "update_backfill_job")
 		if err != nil {
 			return errors.Trace(err)
 		}

ddl/failtest/fail_db_test.go

@@ -29,6 +29,7 @@ import (
 	"github.com/pingcap/tidb/ddl/testutil"
 	ddlutil "github.com/pingcap/tidb/ddl/util"
 	"github.com/pingcap/tidb/domain"
+	"github.com/pingcap/tidb/errno"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/parser/model"
 	"github.com/pingcap/tidb/session"
@@ -220,6 +221,43 @@ func TestAddIndexFailed(t *testing.T) {
 	tk.MustExec("admin check table t")
 }
 
+func TestAddIndexCanceledInDistReorg(t *testing.T) {
+	if !variable.DDLEnableDistributeReorg.Load() {
+		// Non-dist-reorg hasn't this fail-point.
+		return
+	}
+	s := createFailDBSuite(t)
+	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/ddl/MockCanceledErr", `1*return`))
+	defer func() {
+		require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/ddl/MockCanceledErr"))
+	}()
+	tk := testkit.NewTestKit(t, s.store)
+	tk.MustExec("create database if not exists test_add_index_cancel")
+	defer tk.MustExec("drop database test_add_index_cancel")
+	tk.MustExec("use test_add_index_cancel")
+
+	tk.MustExec("create table t(a bigint PRIMARY KEY, b int)")
+	for i := 0; i < 1000; i++ {
+		tk.MustExec(fmt.Sprintf("insert into t values(%v, %v)", i, i))
+	}
+
+	// Get table ID for split.
+	dom := domain.GetDomain(tk.Session())
+	is := dom.InfoSchema()
+	tbl, err := is.TableByName(model.NewCIStr("test_add_index_cancel"), model.NewCIStr("t"))
+	require.NoError(t, err)
+	tblID := tbl.Meta().ID
+
+	// Split the table.
+	tableStart := tablecodec.GenTableRecordPrefix(tblID)
+	s.cluster.SplitKeys(tableStart, tableStart.PrefixNext(), 100)
+
+	tk.MustGetErrCode("alter table t add index idx_b(b)", errno.ErrCancelledDDLJob)
+	tk.MustQuery(fmt.Sprintf("select count(1) from mysql.%s", ddl.BackgroundSubtaskTable)).Check(testkit.Rows("0"))
+	tk.MustQuery(fmt.Sprintf("select count(1) from mysql.%s", ddl.BackgroundSubtaskHistoryTable)).Check(testkit.Rows("100"))
+	tk.MustExec("admin check table t")
+}
+
 // TestFailSchemaSyncer test when the schema syncer is done,
 // should prohibit DML executing until the syncer is restartd by loadSchemaInLoop.
 func TestFailSchemaSyncer(t *testing.T) {

ddl/job_table_test.go

@@ -657,7 +657,7 @@ func TestSimpleExecBackfillJobs(t *testing.T) {
 	allCnt, err = ddl.GetBackfillJobCount(se, ddl.BackgroundSubtaskTable, getIdxConditionStr(jobID2, eleID3), "test_get_bj")
 	require.NoError(t, err)
 	require.Equal(t, allCnt, 2)
-	err = ddl.MoveBackfillJobsToHistoryTable(se, bJobs3[0])
+	err = ddl.MoveBackfillJobsToHistoryTable(se, bJobs3[0].PrefixKeyString())
 	require.NoError(t, err)
 	allCnt, err = ddl.GetBackfillJobCount(se, ddl.BackgroundSubtaskTable, getIdxConditionStr(jobID2, eleID3), "test_get_bj")
 	require.NoError(t, err)
@@ -690,7 +690,7 @@ func TestSimpleExecBackfillJobs(t *testing.T) {
 	allCnt, err = ddl.GetBackfillJobCount(se, ddl.BackgroundSubtaskTable, getIdxConditionStr(jobID1, eleID1), "test_get_bj")
 	require.NoError(t, err)
 	require.Equal(t, allCnt, 6)
-	err = ddl.MoveBackfillJobsToHistoryTable(se, bJobs1[0])
+	err = ddl.MoveBackfillJobsToHistoryTable(se, bJobs1[0].PrefixKeyString())
 	require.NoError(t, err)
 	allCnt, err = ddl.GetBackfillJobCount(se, ddl.BackgroundSubtaskTable, getIdxConditionStr(jobID1, eleID1), "test_get_bj")
 	require.NoError(t, err)