fix: the insert count is zero after set the pointer to nil (#29870)

this leads to the EntitiesNum metric would be never reduced

fix: #29766

Signed-off-by: yah01 <yang.cen@zilliz.com>

internal/querynodev2/segments/segment.go

@@ -250,10 +250,6 @@ func (s *LocalSegment) InsertCount() int64 {
 	s.ptrLock.RLock()
 	defer s.ptrLock.RUnlock()
 
-	if !s.isValid() {
-		return 0
-	}
-
 	return s.insertCount.Load()
 }
 
@@ -1012,5 +1008,6 @@ func (s *LocalSegment) Release() {
 		zap.Int64("partitionID", s.partitionID),
 		zap.Int64("segmentID", s.ID()),
 		zap.String("segmentType", s.typ.String()),
+		zap.Int64("insertCount", s.InsertCount()),
 	)
 }

internal/querynodev2/segments/segment_test.go

@@ -171,7 +171,6 @@ func (suite *SegmentSuite) TestSegmentReleased() {
 	sealed.ptrLock.RLock()
 	suite.False(sealed.isValid())
 	sealed.ptrLock.RUnlock()
-	suite.EqualValues(0, sealed.InsertCount())
 	suite.EqualValues(0, sealed.RowNum())
 	suite.EqualValues(0, sealed.MemSize())
 	suite.False(sealed.HasRawData(101))