planner: add more test cases for non-prep plan cache (#42716)

ref #36598

planner/core/plan_cache_param.go

@@ -58,14 +58,21 @@ type paramReplacer struct {
 	// This is to make the output field names be corresponding to these values.
 	// Use int instead of bool to support nested SelectField.
 	selFieldsCnt int
+
+	// Skip all values in GroupByClause since them can affect the full_group_by check, e.g.
+	// `select a*2 from t group by a*?` cannot pass the full_group_by check.
+	groupByCnt int
 }
 
 func (pr *paramReplacer) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
 	switch n := in.(type) {
 	case *ast.SelectField:
 		pr.selFieldsCnt++
+	case *ast.GroupByClause:
+		pr.groupByCnt++
 	case *driver.ValueExpr:
-		if pr.selFieldsCnt == 0 { // not in SelectField
+		if pr.selFieldsCnt == 0 && // not in SelectField
+			pr.groupByCnt == 0 { // not in GroupBy
 			pr.params = append(pr.params, n)
 			param := ast.NewParamMarkerExpr(len(pr.params) - 1)      // offset is used as order in non-prepared plan cache.
 			param.(*driver.ParamMarkerExpr).Datum = *n.Datum.Clone() // init the ParamMakerExpr's Datum
@@ -76,13 +83,16 @@ func (pr *paramReplacer) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
 }
 
 func (pr *paramReplacer) Leave(in ast.Node) (out ast.Node, ok bool) {
-	if _, ok := in.(*ast.SelectField); ok {
+	switch in.(type) {
+	case *ast.SelectField:
 		pr.selFieldsCnt--
+	case *ast.GroupByClause:
+		pr.groupByCnt--
 	}
 	return in, true
 }
 
-func (pr *paramReplacer) Reset() { pr.params = nil }
+func (pr *paramReplacer) Reset() { pr.params, pr.selFieldsCnt, pr.groupByCnt = nil, 0, 0 }
 
 // ParameterizeAST parameterizes this StmtNode.
 // e.g. `select * from t where a<10 and b<23` --> `select * from t where a<? and b<?`, [10, 23].

planner/core/plan_cache_param_test.go

@@ -68,6 +68,12 @@ func TestParameterize(t *testing.T) {
 			[]interface{}{int64(10)},
 			"SELECT `a`+1 FROM `t` WHERE `a`<10",
 		},
+		{
+			"select a+1, sum(b) from t where a<10 group by a+1",
+			"SELECT `a`+1,SUM(`b`) FROM `t` WHERE `a`<? GROUP BY `a`+1",
+			[]interface{}{int64(10)},
+			"SELECT `a`+1,SUM(`b`) FROM `t` WHERE `a`<10 GROUP BY `a`+1",
+		},
 		// TODO: more test cases
 	}
 

planner/core/plan_cache_test.go

@@ -1440,6 +1440,22 @@ func TestPlanCacheSubquerySPMEffective(t *testing.T) {
 	}
 }
 
+func TestNonPreparedPlanCacheGroupBy(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec("create table t(a int, b int, index(a))")
+	tk.MustExec("set tidb_enable_non_prepared_plan_cache=1")
+
+	tk.MustExec(`select sum(b) from t group by a+1`)
+	tk.MustExec(`select sum(b) from t group by a+1`)
+	tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("1"))
+	tk.MustExec(`select sum(b) from t group by a+2`)
+	tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("0"))
+	tk.MustExec(`select sum(b) from t group by a+2`)
+	tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("1"))
+}
+
 func TestNonPreparedPlanCacheFieldNames(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)