planner: do not convert update to point get if the expr has sub-query (#47454) (#50719)

close #47445

Author: ti-chi-bot

parser/ast/expressions.go

@@ -960,7 +960,7 @@ type ParamMarkerExpr interface {
 	SetOrder(int)
 }
 
-// ParenthesesExpr is the parentheses expression.
+// ParenthesesExpr is the parentheses' expression.
 type ParenthesesExpr struct {
 	exprNode
 	// Expr is the expression in parentheses.

planner/core/plan_test.go

@@ -884,6 +884,22 @@ func TestTableDualAsSubQuery(t *testing.T) {
 	tk.MustQuery("SELECT v0.c0 FROM v0 WHERE (v0.c0 IS NULL) LIKE(NULL);").Check(testkit.Rows())
 	tk.MustQuery("SELECT v0.c0 FROM (SELECT null as c0) v0 WHERE (v0.c0 IS NULL) like (NULL);").Check(testkit.Rows())
 }
+func TestIssue47445(t *testing.T) {
+	store, clean := testkit.CreateMockStore(t)
+	defer clean()
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test;")
+	tk.MustExec("CREATE TABLE golang1 ( `fcbpdt` CHAR (8) COLLATE utf8_general_ci NOT NULL, `fcbpsq` VARCHAR (20) COLLATE utf8_general_ci NOT NULL, `procst` char (4) COLLATE utf8_general_ci DEFAULT NULL,`cipstx` VARCHAR (105) COLLATE utf8_general_ci DEFAULT NULL, `cipsst` CHAR (4) COLLATE utf8_general_ci DEFAULT NULL, `dyngtg` VARCHAR(4) COLLATE utf8_general_ci DEFAULT NULL, `blncdt` VARCHAR (8) COLLATE utf8_general_ci DEFAULT NULL, PRIMARY KEY ( fcbpdt, fcbpsq ))")
+	tk.MustExec("insert into golang1 values('20230925','12023092502158016','abc','','','','')")
+	tk.MustExec("create table golang2 (`sysgrp` varchar(20) NOT NULL,`procst` varchar(8) NOT NULL,`levlid` int(11) NOT NULL,PRIMARY key (procst));")
+	tk.MustExec("insert into golang2 VALUES('COMMON','ACSC',90)")
+	tk.MustExec("insert into golang2 VALUES('COMMON','abc',8)")
+	tk.MustExec("insert into golang2 VALUES('COMMON','CH02',6)")
+	tk.MustExec("UPDATE golang1 a SET procst =(CASE WHEN ( SELECT levlid FROM golang2 b WHERE b.sysgrp = 'COMMON' AND b.procst = 'ACSC' ) > ( SELECT levlid FROM golang2 c WHERE c.sysgrp = 'COMMON' AND c.procst = a.procst ) THEN 'ACSC' ELSE a.procst END ), cipstx = 'CI010000', cipsst = 'ACSC', dyngtg = 'EAYT', blncdt= '20230925' WHERE fcbpdt = '20230925' AND fcbpsq = '12023092502158016'")
+	tk.MustQuery("select * from golang1").Check(testkit.Rows("20230925 12023092502158016 ACSC CI010000 ACSC EAYT 20230925"))
+	tk.MustExec("UPDATE golang1 a SET procst= (SELECT 1 FROM golang2 c WHERE c.procst = a.procst) WHERE fcbpdt = '20230925' AND fcbpsq = '12023092502158016'")
+	tk.MustQuery("select * from golang1").Check(testkit.Rows("20230925 12023092502158016 1 CI010000 ACSC EAYT 20230925"))
+}
 
 // https://github.com/pingcap/tidb/issues/38310
 func TestNullEQConditionPlan(t *testing.T) {

planner/core/point_get_plan.go

@@ -19,6 +19,7 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/pingcap/errors"
 	"github.com/pingcap/tidb/config"
@@ -1365,13 +1366,57 @@ func findInPairs(colName string, pairs []nameValuePair) int {
 	return -1
 }
 
-func tryUpdatePointPlan(ctx sessionctx.Context, updateStmt *ast.UpdateStmt) Plan {
-	// avoid using the point_get when assignment_list contains the subquery in the UPDATE.
-	for _, list := range updateStmt.List {
-		if _, ok := list.Expr.(*ast.SubqueryExpr); ok {
-			return nil
+// Use cache to avoid allocating memory every time.
+var subQueryCheckerPool = &sync.Pool{New: func() any { return &subQueryChecker{} }}
+
+type subQueryChecker struct {
+	hasSubQuery bool
+}
+
+func (s *subQueryChecker) Enter(in ast.Node) (node ast.Node, skipChildren bool) {
+	if s.hasSubQuery {
+		return in, true
+	}
+
+	if _, ok := in.(*ast.SubqueryExpr); ok {
+		s.hasSubQuery = true
+		return in, true
+	}
+
+	return in, false
+}
+
+func (s *subQueryChecker) Leave(in ast.Node) (ast.Node, bool) {
+	// Before we enter the sub-query, we should keep visiting its children.
+	return in, !s.hasSubQuery
+}
+
+func isExprHasSubQuery(expr ast.Node) bool {
+	checker := subQueryCheckerPool.Get().(*subQueryChecker)
+	defer func() {
+		// Do not forget to reset the flag.
+		checker.hasSubQuery = false
+		subQueryCheckerPool.Put(checker)
+	}()
+	expr.Accept(checker)
+	return checker.hasSubQuery
+}
+
+func checkIfAssignmentListHasSubQuery(list []*ast.Assignment) bool {
+	for _, a := range list {
+		if isExprHasSubQuery(a) {
+			return true
 		}
 	}
+	return false
+}
+
+func tryUpdatePointPlan(ctx sessionctx.Context, updateStmt *ast.UpdateStmt) Plan {
+	// Avoid using the point_get when assignment_list contains the sub-query in the UPDATE.
+	if checkIfAssignmentListHasSubQuery(updateStmt.List) {
+		return nil
+	}
+
 	selStmt := &ast.SelectStmt{
 		Fields:  &ast.FieldList{},
 		From:    updateStmt.TableRefs,