From f0fd7957f219fa7e7e3008029fa935989e9dee04 Mon Sep 17 00:00:00 2001
From: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
Date: Tue, 15 Jun 2021 15:20:37 +0800
Subject: [PATCH] planner: forbid prepared stale select in txn (#25375)
 (#25413)

---
 errno/errcode.go             | 1 +
 errno/errname.go             | 1 +
 errors.toml                  | 5 +++++
 executor/stale_txn_test.go   | 4 ++--
 planner/core/common_plans.go | 3 +++
 planner/core/errors.go       | 3 +--
 planner/core/preprocess.go   | 2 +-
 7 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/errno/errcode.go b/errno/errcode.go
index 2a3fe2733b5bf..d6b7c912a15d9 100644
--- a/errno/errcode.go
+++ b/errno/errcode.go
@@ -1005,6 +1005,7 @@ const (
 	ErrNotSupportedWithSem                 = 8132
 	ErrDataInConsistentExtraIndex          = 8133
 	ErrDataInConsistentMisMatchIndex       = 8134
+	ErrAsOf                                = 8135
 
 	// Error codes used by TiDB ddl package
 	ErrUnsupportedDDLOperation            = 8200
diff --git a/errno/errname.go b/errno/errname.go
index 05a8f476f835b..6ab983acc3f29 100644
--- a/errno/errname.go
+++ b/errno/errname.go
@@ -1051,6 +1051,7 @@ var MySQLErrName = map[uint16]*mysql.ErrMessage{
 	ErrInvalidPlacementSpec:   mysql.Message("Invalid placement policy '%s': %s", nil),
 	ErrPlacementPolicyCheck:   mysql.Message("Placement policy didn't meet the constraint, reason: %s", nil),
 	ErrMultiStatementDisabled: mysql.Message("client has multi-statement capability disabled. Run SET GLOBAL tidb_multi_statement_mode='ON' after you understand the security risk", nil),
+	ErrAsOf:                   mysql.Message("invalid as of timestamp: %s", nil),
 
 	// TiKV/PD errors.
 	ErrPDServerTimeout:           mysql.Message("PD server timeout", nil),
diff --git a/errors.toml b/errors.toml
index ce6ce2e58206c..3ef2ba977a86e 100644
--- a/errors.toml
+++ b/errors.toml
@@ -1206,6 +1206,11 @@ error = '''
 Feature '%s' is not supported when security enhanced mode is enabled
 '''
 
+["planner:8135"]
+error = '''
+invalid as of timestamp: %s
+'''
+
 ["privilege:1141"]
 error = '''
 There is no such grant defined for user '%-.48s' on host '%-.64s'
diff --git a/executor/stale_txn_test.go b/executor/stale_txn_test.go
index cd4741fe98db1..ea6982f8aec31 100644
--- a/executor/stale_txn_test.go
+++ b/executor/stale_txn_test.go
@@ -815,7 +815,7 @@ func (s *testStaleTxnSuite) TestStaleSelect(c *C) {
 
 	// test prepared stale select in txn
 	tk.MustExec("begin")
-	tk.MustQuery("execute s").Check(staleRows)
+	c.Assert(tk.ExecToErr(staleSQL), NotNil)
 	tk.MustExec("commit")
 
 	// test stale select in stale txn
@@ -825,7 +825,7 @@ func (s *testStaleTxnSuite) TestStaleSelect(c *C) {
 
 	// test prepared stale select in stale txn
 	tk.MustExec(fmt.Sprintf(`start transaction read only as of timestamp '%s'`, time2.Format("2006-1-2 15:04:05.000")))
-	tk.MustQuery("execute s").Check(staleRows)
+	c.Assert(tk.ExecToErr(staleSQL), NotNil)
 	tk.MustExec("commit")
 
 	// test prepared stale select with schema change
diff --git a/planner/core/common_plans.go b/planner/core/common_plans.go
index 0fdb48169fd4e..ec5833be9973c 100644
--- a/planner/core/common_plans.go
+++ b/planner/core/common_plans.go
@@ -260,6 +260,9 @@ func (e *Execute) OptimizePreparedPlan(ctx context.Context, sctx sessionctx.Cont
 
 	var snapshotTS uint64
 	if preparedObj.SnapshotTSEvaluator != nil {
+		if vars.InTxn() {
+			return ErrAsOf.FastGenWithCause("as of timestamp can't be set in transaction.")
+		}
 		// if preparedObj.SnapshotTSEvaluator != nil, it is a stale read SQL:
 		// which means its infoschema is specified by the SQL, not the current/latest infoschema
 		var err error
diff --git a/planner/core/errors.go b/planner/core/errors.go
index dd457e0ca4efe..04fa1797d95bd 100644
--- a/planner/core/errors.go
+++ b/planner/core/errors.go
@@ -97,7 +97,6 @@ var (
 	ErrAccessDenied        = dbterror.ClassOptimizer.NewStdErr(mysql.ErrAccessDenied, mysql.MySQLErrName[mysql.ErrAccessDeniedNoPassword])
 	ErrBadNull             = dbterror.ClassOptimizer.NewStd(mysql.ErrBadNull)
 	ErrNotSupportedWithSem = dbterror.ClassOptimizer.NewStd(mysql.ErrNotSupportedWithSem)
-	ErrDifferentAsOf       = dbterror.ClassOptimizer.NewStd(mysql.ErrUnknown)
-	ErrAsOf                = dbterror.ClassOptimizer.NewStd(mysql.ErrUnknown)
+	ErrAsOf                = dbterror.ClassOptimizer.NewStd(mysql.ErrAsOf)
 	ErrOptOnTemporaryTable = dbterror.ClassOptimizer.NewStd(mysql.ErrOptOnTemporaryTable)
 )
diff --git a/planner/core/preprocess.go b/planner/core/preprocess.go
index e8cab1bf1551f..e1d0012323f7e 100644
--- a/planner/core/preprocess.go
+++ b/planner/core/preprocess.go
@@ -1425,7 +1425,7 @@ func (p *preprocessor) handleAsOfAndReadTS(node *ast.AsOfClause) {
 		}
 	}
 	if p.LastSnapshotTS != ts {
-		p.err = ErrDifferentAsOf.GenWithStack("can not set different time in the as of")
+		p.err = ErrAsOf.GenWithStack("can not set different time in the as of")
 		return
 	}
 	if p.LastSnapshotTS != 0 {