Skip single compaction if there's no delta log in a segment (#11806)

Signed-off-by: sunby <bingyi.sun@zilliz.com>

Co-authored-by: sunby <bingyi.sun@zilliz.com>

internal/datacoord/compaction_policy.go

@@ -23,13 +23,17 @@ func (f singleCompactionFunc) generatePlan(segment *SegmentInfo, timetravel *tim
 }
 
 func chooseAllBinlogs(segment *SegmentInfo, timetravel *timetravel) *datapb.CompactionPlan {
-	deltaLogs := make([]*datapb.DeltaLogInfo, 0)
+	var deltaLogs []*datapb.DeltaLogInfo
 	for _, l := range segment.GetDeltalogs() {
 		if l.TimestampTo < timetravel.time {
 			deltaLogs = append(deltaLogs, l)
 		}
 	}
 
+	if len(deltaLogs) == 0 {
+		return nil
+	}
+
 	return &datapb.CompactionPlan{
 		SegmentBinlogs: []*datapb.CompactionSegmentBinlogs{
 			{

internal/datacoord/compaction_policy_test.go

@@ -108,3 +108,34 @@ func Test_greedyMergeCompaction(t *testing.T) {
 		})
 	}
 }
+
+func Test_chooseAllBinlogs(t *testing.T) {
+	type args struct {
+		segment    *SegmentInfo
+		timetravel *timetravel
+	}
+	tests := []struct {
+		name string
+		args args
+		want *datapb.CompactionPlan
+	}{
+		{
+			"test no delta logs",
+			args{
+				segment: &SegmentInfo{
+					SegmentInfo: &datapb.SegmentInfo{
+						ID:        1,
+						Deltalogs: nil,
+					},
+				},
+			},
+			nil,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := chooseAllBinlogs(tt.args.segment, tt.args.timetravel)
+			assert.EqualValues(t, tt.want, got)
+		})
+	}
+}