limit the count of getting ddlhistory jobs

Signed-off-by: joccau <[email protected]>

pkg/ddl/ddl_history.go

@@ -37,6 +37,8 @@ import (
 const (
 	DefNumHistoryJobs   = 10
 	batchNumHistoryJobs = 128
+	// GetDDLHistoryCountMax is the max count for getting the ddl history once.
+	GetDDLHistoryCountMax = 1024
 )
 
 // AddHistoryDDLJob record the history job.
@@ -150,9 +152,15 @@ func GetAllHistoryDDLJobs(m *meta.Meta) ([]*model.Job, error) {
 func ScanHistoryDDLJobs(m *meta.Meta, startJobID int64, limit int) ([]*model.Job, error) {
 	var iter meta.LastJobIterator
 	var err error
+
 	if startJobID == 0 {
+		// if 'start_job_id' == 0 and 'limit' == 0(default value), get the 1024 ddl history job by defaultly.
+		if limit == 0 {
+			limit = GetDDLHistoryCountMax
+		}
 		iter, err = m.GetLastHistoryDDLJobsIterator()
 	} else {
+		// if 'start_job_id' > 0, it must set value to 'limit'
 		if limit == 0 {
 			return nil, errors.New("when 'start_job_id' is specified, it must work with a 'limit'")
 		}

pkg/ddl/ddl_history_test.go

@@ -97,3 +97,14 @@ func TestDDLHistoryBasic(t *testing.T) {
 
 	require.NoError(t, err)
 }
+
+func TestScanHistoryDDLJobsWithErrorLimit(t *testing.T) {
+	var (
+		m                = &meta.Meta{}
+		startJobID int64 = 10
+		limit            = 0
+	)
+
+	_, err := ddl.ScanHistoryDDLJobs(m, startJobID, limit)
+	require.ErrorContains(t, err, "when 'start_job_id' is specified, it must work with a 'limit'")
+}

pkg/server/handler/tikvhandler/tikv_handler.go

@@ -1125,8 +1125,11 @@ func (h *TableHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 
 // ServeHTTP handles request of ddl jobs history.
 func (h DDLHistoryJobHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
-	var jobID, limitID int
-	var err error
+	var (
+		jobID   = 0
+		limitID = 0
+		err     error
+	)
 	if jobValue := req.FormValue(handler.JobID); len(jobValue) > 0 {
 		jobID, err = strconv.Atoi(jobValue)
 		if err != nil {
@@ -1144,8 +1147,9 @@ func (h DDLHistoryJobHandler) ServeHTTP(w http.ResponseWriter, req *http.Request
 			handler.WriteError(w, err)
 			return
 		}
-		if limitID < 1 {
-			handler.WriteError(w, errors.New("ddl history limit must be greater than 0"))
+		if limitID < 1 || limitID > ddl.GetDDLHistoryCountMax {
+			handler.WriteError(w,
+				errors.Errorf("ddl history limit must be greater than 0 and less than or equal to %v", ddl.GetDDLHistoryCountMax))
 			return
 		}
 	}
@@ -1165,11 +1169,7 @@ func (h DDLHistoryJobHandler) getHistoryDDL(jobID, limit int) (jobs []*model.Job
 	}
 	txnMeta := meta.NewMeta(txn)
 
-	if jobID == 0 && limit == 0 {
-		jobs, err = ddl.GetAllHistoryDDLJobs(txnMeta)
-	} else {
-		jobs, err = ddl.ScanHistoryDDLJobs(txnMeta, int64(jobID), limit)
-	}
+	jobs, err = ddl.ScanHistoryDDLJobs(txnMeta, int64(jobID), limit)
 	if err != nil {
 		return nil, errors.Trace(err)
 	}