From 9876de8961277e45fe432b56bd46ff24733af059 Mon Sep 17 00:00:00 2001
From: Null not nil <67764674+nullnotnil@users.noreply.github.com>
Date: Fri, 18 Sep 2020 05:18:37 -0600
Subject: [PATCH] planner: disable SQL_CALC_FOUND_ROWS/LOCK IN SHARE MODE by
 default (#19506)

---
 expression/integration_test.go       | 17 +++++++++++++++++
 planner/core/logical_plan_builder.go | 11 +++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/expression/integration_test.go b/expression/integration_test.go
index 3418588e44..d43190ed2e 100755
--- a/expression/integration_test.go
+++ b/expression/integration_test.go
@@ -7226,6 +7226,23 @@ func (s *testIntegrationSerialSuite) TestIssue19116(c *C) {
 	tk.MustQuery("select coercibility(1=1);").Check(testkit.Rows("5"))
 }
 
+func (s *testIntegrationSerialSuite) TestIssue14448and19383(c *C) {
+	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("use test")
+	tk.MustExec("DROP TABLE IF EXISTS t1")
+	tk.MustExec("CREATE TABLE t1 (a INT NOT NULL PRIMARY KEY)")
+	tk.MustExec("INSERT INTO t1 VALUES (1),(2),(3)")
+	_, err := tk.Exec("SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1")
+	message := `function SQL_CALC_FOUND_ROWS has only noop implementation in tidb now, use tidb_enable_noop_functions to enable these functions`
+	c.Assert(strings.Contains(err.Error(), message), IsTrue)
+	_, err = tk.Exec("SELECT * FROM t1 LOCK IN SHARE MODE")
+	message = `function LOCK IN SHARE MODE has only noop implementation in tidb now, use tidb_enable_noop_functions to enable these functions`
+	c.Assert(strings.Contains(err.Error(), message), IsTrue)
+	tk.MustExec("SET tidb_enable_noop_functions=1")
+	tk.MustExec("SELECT SQL_CALC_FOUND_ROWS * FROM t1 LIMIT 1")
+	tk.MustExec("SELECT * FROM t1 LOCK IN SHARE MODE")
+}
+
 func (s *testIntegrationSerialSuite) TestIssue19315(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
diff --git a/planner/core/logical_plan_builder.go b/planner/core/logical_plan_builder.go
index 3d67b1201b..685be8d4ef 100644
--- a/planner/core/logical_plan_builder.go
+++ b/planner/core/logical_plan_builder.go
@@ -2604,8 +2604,12 @@ func (b *PlanBuilder) buildSelect(ctx context.Context, sel *ast.SelectStmt) (p L
 		// table hints are only visible in the current SELECT statement.
 		b.popTableHints()
 	}()
-
+	enableNoopFuncs := b.ctx.GetSessionVars().EnableNoopFuncs
 	if sel.SelectStmtOpts != nil {
+		if sel.SelectStmtOpts.CalcFoundRows && !enableNoopFuncs {
+			err = expression.ErrFunctionsNoopImpl.GenWithStackByArgs("SQL_CALC_FOUND_ROWS")
+			return nil, err
+		}
 		origin := b.inStraightJoin
 		b.inStraightJoin = sel.SelectStmtOpts.StraightJoin
 		defer func() { b.inStraightJoin = origin }()
@@ -2671,8 +2675,11 @@ func (b *PlanBuilder) buildSelect(ctx context.Context, sel *ast.SelectStmt) (p L
 			return nil, err
 		}
 	}
-
 	if sel.LockInfo != nil && sel.LockInfo.LockType != ast.SelectLockNone {
+		if sel.LockInfo.LockType == ast.SelectLockInShareMode && !enableNoopFuncs {
+			err = expression.ErrFunctionsNoopImpl.GenWithStackByArgs("LOCK IN SHARE MODE")
+			return nil, err
+		}
 		p = b.buildSelectLock(p, sel.LockInfo)
 	}
 	b.handleHelper.popMap()