Cache segment row num, size, and insert count to reduce CGO calls (#28007)

Signed-off-by: yah01 <yah2er0ne@outlook.com>

internal/querynodev2/segments/segment.go

@@ -144,8 +144,11 @@ type LocalSegment struct {
 	ptrLock sync.RWMutex // protects segmentPtr
 	ptr     C.CSegmentInterface
 
-	size               int64
-	row                int64
+	// cached results, to avoid too many CGO calls
+	memSize     *atomic.Int64
+	rowNum      *atomic.Int64
+	insertCount *atomic.Int64
+
 	lastDeltaTimestamp *atomic.Uint64
 	fieldIndexes       *typeutil.ConcurrentMap[int64, *IndexedFieldInfo]
 }
@@ -185,6 +188,10 @@ func NewSegment(collection *Collection,
 		ptr:                segmentPtr,
 		lastDeltaTimestamp: atomic.NewUint64(0),
 		fieldIndexes:       typeutil.NewConcurrentMap[int64, *IndexedFieldInfo](),
+
+		memSize:     atomic.NewInt64(-1),
+		rowNum:      atomic.NewInt64(-1),
+		insertCount: atomic.NewInt64(0),
 	}
 
 	return segment, nil
@@ -217,13 +224,8 @@ func (s *LocalSegment) InsertCount() int64 {
 	if !s.isValid() {
 		return 0
 	}
-	var rowCount C.int64_t
-	GetDynamicPool().Submit(func() (any, error) {
-		rowCount = C.GetRowCount(s.ptr)
-		return nil, nil
-	}).Await()
 
-	return int64(rowCount)
+	return s.insertCount.Load()
 }
 
 func (s *LocalSegment) RowNum() int64 {
@@ -233,13 +235,19 @@ func (s *LocalSegment) RowNum() int64 {
 	if !s.isValid() {
 		return 0
 	}
-	var rowCount C.int64_t
-	GetDynamicPool().Submit(func() (any, error) {
-		rowCount = C.GetRealCount(s.ptr)
-		return nil, nil
-	}).Await()
 
-	return int64(rowCount)
+	rowNum := s.rowNum.Load()
+	if rowNum < 0 {
+		var rowCount C.int64_t
+		GetDynamicPool().Submit(func() (any, error) {
+			rowCount = C.GetRealCount(s.ptr)
+			s.rowNum.Store(int64(rowCount))
+			return nil, nil
+		}).Await()
+		rowNum = int64(rowCount)
+	}
+
+	return rowNum
 }
 
 func (s *LocalSegment) MemSize() int64 {
@@ -249,13 +257,19 @@ func (s *LocalSegment) MemSize() int64 {
 	if !s.isValid() {
 		return 0
 	}
-	var memoryUsageInBytes C.int64_t
-	GetDynamicPool().Submit(func() (any, error) {
-		memoryUsageInBytes = C.GetMemoryUsageInBytes(s.ptr)
-		return nil, nil
-	}).Await()
 
-	return int64(memoryUsageInBytes)
+	memSize := s.memSize.Load()
+	if memSize < 0 {
+		var cMemSize C.int64_t
+		GetDynamicPool().Submit(func() (any, error) {
+			cMemSize = C.GetMemoryUsageInBytes(s.ptr)
+			s.memSize.Store(int64(cMemSize))
+			return nil, nil
+		}).Await()
+
+		memSize = int64(cMemSize)
+	}
+	return memSize
 }
 
 func (s *LocalSegment) LastDeltaTimestamp() uint64 {
@@ -498,6 +512,10 @@ func (s *LocalSegment) Insert(rowIDs []int64, timestamps []typeutil.Timestamp, r
 	if err := HandleCStatus(&status, "Insert failed"); err != nil {
 		return err
 	}
+
+	s.insertCount.Add(int64(numOfRow))
+	s.rowNum.Store(-1)
+	s.memSize.Store(-1)
 	metrics.QueryNodeNumEntities.WithLabelValues(
 		fmt.Sprint(paramtable.GetNodeID()),
 		fmt.Sprint(s.collectionID),
@@ -576,6 +594,7 @@ func (s *LocalSegment) Delete(primaryKeys []storage.PrimaryKey, timestamps []typ
 		return err
 	}
 
+	s.rowNum.Store(-1)
 	s.lastDeltaTimestamp.Store(timestamps[len(timestamps)-1])
 
 	return nil
@@ -628,6 +647,7 @@ func (s *LocalSegment) LoadMultiFieldData(rowCount int64, fields []*datapb.Field
 		return err
 	}
 
+	s.insertCount.Store(rowCount)
 	log.Info("load mutil field done",
 		zap.Int64("row count", rowCount),
 		zap.Int64("segmentID", s.ID()))
@@ -681,6 +701,7 @@ func (s *LocalSegment) LoadFieldData(fieldID int64, rowCount int64, field *datap
 		return err
 	}
 
+	s.insertCount.Store(rowCount)
 	log.Info("load field done")
 
 	return nil
@@ -804,6 +825,7 @@ func (s *LocalSegment) LoadDeltaData(deltaData *storage.DeleteData) error {
 		return err
 	}
 
+	s.rowNum.Store(-1)
 	s.lastDeltaTimestamp.Store(tss[len(tss)-1])
 
 	log.Info("load deleted record done",