address comment

ddl/db_test.go

@@ -3076,17 +3076,32 @@ func (s *testDBSuite) TestAlterTableTruncatePartition(c *C) {
 
 	s.testErrorCode(c, "alter table employees truncate partition xxx", tmysql.ErrUnknownPartition)
 
+	ctx := s.tk.Se.(sessionctx.Context)
+	is := domain.GetDomain(ctx).InfoSchema()
+	oldTblInfo, err := is.TableByName(model.NewCIStr("test"), model.NewCIStr("employees"))
+	c.Assert(err, IsNil)
+	oldPID := oldTblInfo.Meta().Partition.Definitions[0].ID
+
 	s.tk.MustExec("alter table employees truncate partition p1")
 	result = s.tk.MustQuery("select * from employees order by id")
 	result.Check(testkit.Rows(`2 1995`, `3 2000`))
 
+	is = domain.GetDomain(ctx).InfoSchema()
+	oldTblInfo, err = is.TableByName(model.NewCIStr("test"), model.NewCIStr("employees"))
+	c.Assert(err, IsNil)
+	newPID := oldTblInfo.Meta().Partition.Definitions[0].ID
+	c.Assert(oldPID != newPID, IsTrue)
+
 	s.tk.MustExec("alter table employees truncate partition p3")
 	result = s.tk.MustQuery("select * from employees")
 	result.Check(testkit.Rows(`2 1995`))
 
 	s.tk.MustExec("insert into employees values (1, 1984)")
 	result = s.tk.MustQuery("select * from employees order by id")
 	result.Check(testkit.Rows(`1 1984`, `2 1995`))
+	s.tk.MustExec("insert into employees values (3, 2000)")
+	result = s.tk.MustQuery("select * from employees order by id")
+	result.Check(testkit.Rows(`1 1984`, `2 1995`, `3 2000`))
 
 	s.tk.MustExec(`create table non_partition (id int)`)
 	s.testErrorCode(c, "alter table non_partition truncate partition p0", tmysql.ErrPartitionMgmtOnNonpartitioned)

ddl/ddl_api.go

@@ -1435,7 +1435,9 @@ func (d *ddl) TruncateTablePartition(ctx sessionctx.Context, ident ast.Ident, sp
 		return errors.Trace(ErrPartitionMgmtOnNonpartitioned)
 	}
 
-	if err = checkPartitionExist(meta, spec.Name); err != nil {
+	var pid int64
+	pid, err = findPartitionByName(meta, spec.Name)
+	if err != nil {
 		return errors.Trace(err)
 	}
 
@@ -1444,7 +1446,7 @@ func (d *ddl) TruncateTablePartition(ctx sessionctx.Context, ident ast.Ident, sp
 		TableID:    meta.ID,
 		Type:       model.ActionTruncateTablePartition,
 		BinlogInfo: &model.HistoryInfo{},
-		Args:       []interface{}{spec.Name},
+		Args:       []interface{}{pid},
 	}
 
 	err = d.doDDLJob(ctx, job)

ddl/ddl_worker.go

@@ -285,7 +285,7 @@ func (w *worker) finishDDLJob(t *meta.Meta, job *model.Job) (err error) {
 
 			// After rolling back an AddIndex operation, we need to use delete-range to delete the half-done index data.
 			err = w.deleteRange(job)
-		case model.ActionDropSchema, model.ActionDropTable, model.ActionTruncateTable, model.ActionDropIndex, model.ActionDropTablePartition:
+		case model.ActionDropSchema, model.ActionDropTable, model.ActionTruncateTable, model.ActionDropIndex, model.ActionDropTablePartition, model.ActionTruncateTablePartition:
 			err = w.deleteRange(job)
 		}
 		if err != nil {

ddl/partition.go

@@ -318,15 +318,16 @@ func checkDropTablePartition(meta *model.TableInfo, partName string) error {
 	return errors.Trace(ErrDropPartitionNonExistent.GenWithStackByArgs(partName))
 }
 
-func checkPartitionExist(meta *model.TableInfo, parName string) error {
+func findPartitionByName(meta *model.TableInfo, parName string) (int64, error) {
 	// TODO: MySQL behavior for hash partition is weird, "create table .. partition by hash partition 4",
 	// it use p0, p1, p2, p3 as partition names automatically.
+	parName = strings.ToLower(parName)
 	for _, def := range meta.Partition.Definitions {
-		if strings.EqualFold(def.Name.L, strings.ToLower(parName)) {
-			return nil
+		if strings.EqualFold(def.Name.L, parName) {
+			return def.ID, nil
 		}
 	}
-	return errors.Trace(errUnknownPartition.GenWithStackByArgs(parName, meta.Name.O))
+	return -1, errors.Trace(errUnknownPartition.GenWithStackByArgs(parName, meta.Name.O))
 }
 
 // removePartitionInfo each ddl job deletes a partition.
@@ -379,8 +380,8 @@ func onDropTablePartition(t *meta.Meta, job *model.Job) (ver int64, _ error) {
 // onDropTablePartition truncates old partition meta.
 func onTruncateTablePartition(t *meta.Meta, job *model.Job) (int64, error) {
 	var ver int64
-	var partName string
-	if err := job.DecodeArgs(&partName); err != nil {
+	var oldID int64
+	if err := job.DecodeArgs(&oldID); err != nil {
 		job.State = model.JobStateCancelled
 		return ver, errors.Trace(err)
 	}
@@ -393,21 +394,21 @@ func onTruncateTablePartition(t *meta.Meta, job *model.Job) (int64, error) {
 		return ver, errors.Trace(ErrPartitionMgmtOnNonpartitioned)
 	}
 
-	oldID := int64(-1)
+	var find bool
 	for i := 0; i < len(pi.Definitions); i++ {
 		def := &pi.Definitions[i]
-		if strings.EqualFold(def.Name.L, strings.ToLower(partName)) {
+		if def.ID == oldID {
 			pid, err1 := t.GenGlobalID()
 			if err != nil {
 				return ver, errors.Trace(err1)
 			}
-			oldID = def.ID
 			def.ID = pid
+			find = true
 			break
 		}
 	}
-	if oldID == -1 {
-		return ver, errUnknownPartition.GenWithStackByArgs(partName, tblInfo.Name.O)
+	if !find {
+		return ver, errUnknownPartition.GenWithStackByArgs("drop?", tblInfo.Name.O)
 	}
 
 	ver, err = updateVersionAndTableInfo(t, job, tblInfo, true)

go.sum

@@ -146,6 +146,7 @@ github.com/struCoder/pidusage v0.1.2 h1:fFPTThlcWFQyizv3xKs5Lyq1lpG5lZ36arEGNhWz
 github.com/struCoder/pidusage v0.1.2/go.mod h1:pWBlW3YuSwRl6h7R5KbvA4N8oOqe9LjaKW5CwT1SPjI=
 github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2 h1:mbAskLJ0oJfDRtkanvQPiooDH8HvJ2FBh+iKT/OmiQQ=
 github.com/tiancaiamao/appdash v0.0.0-20181126055449-889f96f722a2/go.mod h1:2PfKggNGDuadAa0LElHrByyrz4JPZ9fFx6Gs7nx7ZZU=
+github.com/tiancaiamao/parser v0.0.0-20181208164110-006feb484d18 h1:RdlDWP22IHOuC6abVahq+4m9Fl9W+NakecOCTaGsG6g=
 github.com/tiancaiamao/parser v0.0.0-20181208164110-006feb484d18/go.mod h1:vqvanuOAAZ9O2rVI51fUrA9P3nV7HoILjLby0/OKOqA=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20171017195756-830351dc03c6 h1:lYIiVDtZnyTWlNwiAxLj0bbpTcx1BWCFhXjfsvmPdNc=
 github.com/tmc/grpc-websocket-proxy v0.0.0-20171017195756-830351dc03c6/go.mod h1:ncp9v5uamzpCO7NfCPTXjqaC+bZgJeR0sMTm6dMHP7U=