Merge branch 'cherrypick/2.0-uservar' of https://github.com/zz-jason/…

…tidb into cherrypick/2.0-uservar

parser/opcode/opcode.go

@@ -134,5 +134,5 @@ var opsLiteral = map[Op]string{
 
 // Format the ExprNode into a Writer.
 func (o Op) Format(w io.Writer) {
-	fmt.Fprintf(w, opsLiteral[o])
+	fmt.Fprintf(w, "%s", opsLiteral[o])
 }

parser/opcode/opcode_test.go

@@ -13,14 +13,29 @@
 
 package opcode
 
-import "testing"
+import (
+	"bytes"
+	"testing"
+)
 
 func TestT(t *testing.T) {
 	op := Plus
 	if op.String() != "plus" {
 		t.Fatalf("invalid op code")
 	}
 
+	if len(Ops) != len(opsLiteral) {
+		t.Error("inconsistent count ops and opsliteral")
+	}
+	var buf bytes.Buffer
+	for op := range Ops {
+		op.Format(&buf)
+		if buf.String() != opsLiteral[op] {
+			t.Error("format op fail", op)
+		}
+		buf.Reset()
+	}
+
 	// Test invalid opcode
 	defer func() {
 		recover()

session/session.go

@@ -401,6 +401,7 @@ func (s *session) CommitTxn(ctx context.Context) error {
 	if err != nil {
 		label = metrics.LblError
 	}
+	s.sessionVars.TxnCtx.Cleanup()
 	metrics.TransactionCounter.WithLabelValues(label).Inc()
 	return errors.Trace(err)
 }
@@ -418,6 +419,7 @@ func (s *session) RollbackTxn(ctx context.Context) error {
 	}
 	s.cleanRetryInfo()
 	s.txn.changeToInvalid()
+	s.sessionVars.TxnCtx.Cleanup()
 	s.sessionVars.SetStatusFlag(mysql.ServerStatusInTrans, false)
 	return errors.Trace(err)
 }

session/txn.go

@@ -195,6 +195,10 @@ func (st *TxnState) cleanup() {
 		delete(st.mutations, key)
 	}
 	if st.dirtyTableOP != nil {
+		empty := dirtyTableOperation{}
+		for i := 0; i < len(st.dirtyTableOP); i++ {
+			st.dirtyTableOP[i] = empty
+		}
 		st.dirtyTableOP = st.dirtyTableOP[:0]
 	}
 }

sessionctx/variable/session.go

@@ -118,6 +118,15 @@ func (tc *TransactionContext) UpdateDeltaForTable(tableID int64, delta int64, co
 	tc.TableDeltaMap[tableID] = item
 }
 
+// Cleanup clears up transaction info that no longer use.
+func (tc *TransactionContext) Cleanup() {
+	//tc.InfoSchema = nil; we cannot do it now, because some operation like handleFieldList depend on this.
+	tc.DirtyDB = nil
+	tc.Binlog = nil
+	tc.Histroy = nil
+	tc.TableDeltaMap = nil
+}
+
 // ClearDelta clears the delta map.
 func (tc *TransactionContext) ClearDelta() {
 	tc.TableDeltaMap = nil