fix: l0RowCount metrics value always empty (#37306)

See also: #36953

---------

Signed-off-by: yangxuan <xuan.yang@zilliz.com>

internal/datacoord/meta.go

@@ -727,17 +727,14 @@ func CreateL0Operator(collectionID, partitionID, segmentID int64, channel string
 				zap.Int64("partitionID", partitionID),
 				zap.Int64("segmentID", segmentID))
 
-			modPack.segments[segmentID] = &SegmentInfo{
-				SegmentInfo: &datapb.SegmentInfo{
+			modPack.segments[segmentID] = NewSegmentInfo(&datapb.SegmentInfo{
 				ID:            segmentID,
 				CollectionID:  collectionID,
 				PartitionID:   partitionID,
 				InsertChannel: channel,
-					NumOfRows:     0,
 				State:         commonpb.SegmentState_Flushed,
 				Level:         datapb.SegmentLevel_L0,
-				},
-			}
+			})
 			modPack.metricMutation.addNewSeg(commonpb.SegmentState_Flushed, datapb.SegmentLevel_L0, false, 0)
 		}
 		return true
@@ -882,6 +879,10 @@ func AddBinlogsOperator(segmentID int64, binlogs, statslogs, deltalogs, bm25logs
 		segment.Binlogs = mergeFieldBinlogs(segment.GetBinlogs(), binlogs)
 		segment.Statslogs = mergeFieldBinlogs(segment.GetStatslogs(), statslogs)
 		segment.Deltalogs = mergeFieldBinlogs(segment.GetDeltalogs(), deltalogs)
+		if len(deltalogs) > 0 {
+			segment.deltaRowcount.Store(-1)
+		}
+
 		segment.Bm25Statslogs = mergeFieldBinlogs(segment.GetBm25Statslogs(), bm25logs)
 		modPack.increments[segmentID] = metastore.BinlogsIncrement{
 			Segment: segment.SegmentInfo,

internal/datacoord/meta_test.go

@@ -25,6 +25,7 @@ import (
 	"github.com/samber/lo"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/require"
 	"github.com/stretchr/testify/suite"
 	"golang.org/x/exp/slices"
 	"google.golang.org/protobuf/proto"
@@ -736,13 +737,15 @@ func TestUpdateSegmentsInfo(t *testing.T) {
 		meta, err := newMemoryMeta()
 		assert.NoError(t, err)
 
-		segment1 := &SegmentInfo{SegmentInfo: &datapb.SegmentInfo{
+		segment1 := NewSegmentInfo(&datapb.SegmentInfo{
 			ID: 1, State: commonpb.SegmentState_Growing,
 			Binlogs:   []*datapb.FieldBinlog{getFieldBinlogIDs(1, 2)},
 			Statslogs: []*datapb.FieldBinlog{getFieldBinlogIDs(1, 2)},
-		}}
+		})
 		err = meta.AddSegment(context.TODO(), segment1)
 		assert.NoError(t, err)
+		require.EqualValues(t, -1, segment1.deltaRowcount.Load())
+		assert.EqualValues(t, 0, segment1.getDeltaCount())
 
 		err = meta.UpdateSegmentsInfo(
 			UpdateStatusOperator(1, commonpb.SegmentState_Flushing),
@@ -758,6 +761,9 @@ func TestUpdateSegmentsInfo(t *testing.T) {
 		assert.NoError(t, err)
 
 		updated := meta.GetHealthySegment(1)
+		assert.EqualValues(t, -1, updated.deltaRowcount.Load())
+		assert.EqualValues(t, 1, updated.getDeltaCount())
+
 		expected := &SegmentInfo{SegmentInfo: &datapb.SegmentInfo{
 			ID: 1, State: commonpb.SegmentState_Flushing, NumOfRows: 10,
 			StartPosition: &msgpb.MsgPosition{MsgID: []byte{1, 2, 3}},

internal/datacoord/segment_info.go

@@ -508,9 +508,9 @@ func (s *SegmentInfo) getSegmentSize() int64 {
 	return s.size.Load()
 }
 
-// getDeltaCount use cached value when segment is immutable
+// Any edits on deltalogs of flushed segments will reset deltaRowcount to -1
 func (s *SegmentInfo) getDeltaCount() int64 {
-	if s.deltaRowcount.Load() < 0 || s.State != commonpb.SegmentState_Flushed {
+	if s.deltaRowcount.Load() < 0 || s.GetState() != commonpb.SegmentState_Flushed {
 		var rc int64
 		for _, deltaLogs := range s.GetDeltalogs() {
 			for _, l := range deltaLogs.GetBinlogs() {