*: fix the read-only check for the prepare/execute statement (pingcap…

…#9723)

executor/adapter.go

@@ -163,15 +163,18 @@ func (a *ExecStmt) IsPrepared() bool {
 }
 
 // IsReadOnly returns true if a statement is read only.
-// It will update readOnlyCheckStmt if current ExecStmt can be conveted to
-// a plannercore.Execute. Last step is using ast.IsReadOnly function to determine
-// a statement is read only or not.
-func (a *ExecStmt) IsReadOnly() bool {
-	readOnlyCheckStmt := a.StmtNode
-	if checkPlan, ok := a.Plan.(*plannercore.Execute); ok {
-		readOnlyCheckStmt = checkPlan.Stmt
-	}
-	return ast.IsReadOnly(readOnlyCheckStmt)
+// If current StmtNode is an ExecuteStmt, we can get its prepared stmt,
+// then using ast.IsReadOnly function to determine a statement is read only or not.
+func (a *ExecStmt) IsReadOnly(vars *variable.SessionVars) bool {
+	if execStmt, ok := a.StmtNode.(*ast.ExecuteStmt); ok {
+		s, err := getPreparedStmt(execStmt, vars)
+		if err != nil {
+			logutil.Logger(context.Background()).Error("getPreparedStmt failed", zap.Error(err))
+			return false
+		}
+		return ast.IsReadOnly(s)
+	}
+	return ast.IsReadOnly(a.StmtNode)
 }
 
 // RebuildPlan rebuilds current execute statement plan.

executor/executor.go

@@ -1260,6 +1260,9 @@ func ResetContextOfStmt(ctx sessionctx.Context, s ast.StmtNode) (err error) {
 
 	if execStmt, ok := s.(*ast.ExecuteStmt); ok {
 		s, err = getPreparedStmt(execStmt, vars)
+		if err != nil {
+			return
+		}
 	}
 	// TODO: Many same bool variables here.
 	// We should set only two variables (

session/session.go

@@ -523,9 +523,6 @@ func (s *session) retry(ctx context.Context, maxCnt uint) (err error) {
 		s.sessionVars.RetryInfo.ResetOffset()
 		for i, sr := range nh.history {
 			st := sr.st
-			if st.IsReadOnly() {
-				continue
-			}
 			s.sessionVars.StmtCtx = sr.stmtCtx
 			s.sessionVars.StmtCtx.ResetForRetry()
 			s.sessionVars.PreparedParams = s.sessionVars.PreparedParams[:0]

session/session_test.go

@@ -923,6 +923,25 @@ func (s *testSessionSuite) TestAutoIncrementWithRetry(c *C) {
 	c.Assert(lastInsertID+3, Equals, currLastInsertID)
 }
 
+func (s *testSessionSuite) TestBinaryReadOnly(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec("create table t (i int key)")
+	id, _, _, err := tk.Se.PrepareStmt("select i from t where i = ?")
+	c.Assert(err, IsNil)
+	id2, _, _, err := tk.Se.PrepareStmt("insert into t values (?)")
+	c.Assert(err, IsNil)
+	tk.MustExec("set autocommit = 0")
+	_, err = tk.Se.ExecutePreparedStmt(context.Background(), id, 1)
+	c.Assert(err, IsNil)
+	c.Assert(session.GetHistory(tk.Se).Count(), Equals, 0)
+	tk.MustExec("insert into t values (1)")
+	c.Assert(session.GetHistory(tk.Se).Count(), Equals, 1)
+	_, err = tk.Se.ExecutePreparedStmt(context.Background(), id2, 2)
+	c.Assert(err, IsNil)
+	c.Assert(session.GetHistory(tk.Se).Count(), Equals, 2)
+	tk.MustExec("commit")
+}
+
 func (s *testSessionSuite) TestPrepare(c *C) {
 	tk := testkit.NewTestKitWithInit(c, s.store)
 	tk.MustExec("create table t(id TEXT)")

session/tidb.go

@@ -193,7 +193,7 @@ func runStmt(ctx context.Context, sctx sessionctx.Context, s sqlexec.Statement)
 	sessVars := se.GetSessionVars()
 	// All the history should be added here.
 	sessVars.TxnCtx.StatementCount++
-	if !s.IsReadOnly() {
+	if !s.IsReadOnly(sessVars) {
 		if err == nil {
 			GetHistory(sctx).Add(0, s, se.sessionVars.StmtCtx)
 		}

util/sqlexec/restricted_sql_executor.go

@@ -16,6 +16,7 @@ package sqlexec
 import (
 	"github.com/pingcap/parser/ast"
 	"github.com/pingcap/tidb/sessionctx"
+	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/util/chunk"
 	"golang.org/x/net/context"
 )
@@ -69,7 +70,7 @@ type Statement interface {
 	IsPrepared() bool
 
 	// IsReadOnly returns if the statement is read only. For example: SelectStmt without lock.
-	IsReadOnly() bool
+	IsReadOnly(vars *variable.SessionVars) bool
 
 	// RebuildPlan rebuilds the plan of the statement.
 	RebuildPlan() (schemaVersion int64, err error)