session: fix the problem that lost connection in t ... (#18567) (#18724)

session/txn.go

@@ -545,17 +545,10 @@ func (s *session) HasDirtyContent(tid int64) bool {
 // StmtCommit implements the sessionctx.Context interface.
 func (s *session) StmtCommit(memTracker *memory.Tracker) error {
 	defer func() {
-		// If StmtCommit is called in batch mode, we need to clear the txn size
-		// in memTracker to avoid double-counting. If it's not batch mode, this
-		// work has no effect because that no more data will be appended into
-		// s.txn.
-		if memTracker != nil {
-			memTracker.Consume(int64(-s.txn.Size()))
-		}
 		s.txn.cleanup()
 	}()
+
 	st := &s.txn
-	txnSize := st.Transaction.Size()
 
 	if _, err := st.Flush(); err != nil {
 		return err
@@ -571,9 +564,6 @@ func (s *session) StmtCommit(memTracker *memory.Tracker) error {
 		st.doNotCommit = err
 		return err
 	}
-	if memTracker != nil {
-		memTracker.Consume(int64(st.Transaction.Size() - txnSize))
-	}
 
 	// Need to flush binlog.
 	for tableID, delta := range st.mutations {