fix: Fix incorrect segment num rows (#34441)

Repeated calls to UpdateStatistics, this PR correct it.

issue: https://github.com/milvus-io/milvus/issues/34440

---------

Signed-off-by: bigsheeper <yihao.dai@zilliz.com>

internal/datanode/writebuffer/insert_buffer.go

@@ -107,7 +107,6 @@ func (ib *InsertBuffer) buffer(inData *storage.InsertData, tr TimeRange, startPo
 	// buffer := ib.currentBuffer()
 	// storage.MergeInsertData(buffer.buffer, inData)
 	ib.buffers = append(ib.buffers, inData)
-	ib.UpdateStatistics(int64(inData.GetRowNum()), int64(inData.GetMemorySize()), tr, startPos, endPos)
 }
 
 func (ib *InsertBuffer) Yield() []*storage.InsertData {

internal/datanode/writebuffer/write_buffer.go

@@ -597,7 +597,7 @@ func (wb *writeBufferBase) getSyncTask(ctx context.Context, segmentID int64) (sy
 	actions := []metacache.SegmentAction{}
 
 	for _, chunk := range insert {
-		batchSize = int64(chunk.GetRowNum())
+		batchSize += int64(chunk.GetRowNum())
 		totalMemSize += float64(chunk.GetMemorySize())
 	}