planner: update the non-prep cacheable checker

planner/core/plan_cache_test.go

@@ -82,6 +82,25 @@ func TestInitLRUWithSystemVar(t *testing.T) {
 	require.NotNil(t, lru)
 }
 
+func TestIssue40296(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec(`CREATE TABLE IDT_MULTI15880STROBJSTROBJ (
+  COL1 enum('aa','bb','cc','dd','ff','gg','kk','ll','mm','ee') DEFAULT NULL,
+  COL2 decimal(20,0) DEFAULT NULL,
+  COL3 date DEFAULT NULL,
+  KEY U_M_COL4 (COL1,COL2),
+  KEY U_M_COL5 (COL3,COL2))`)
+	tk.MustExec(`insert into IDT_MULTI15880STROBJSTROBJ values("ee", -9605492323393070105, "0850-03-15")`)
+	tk.MustExec(`set tidb_enable_non_prepared_plan_cache=on`)
+	tk.MustQuery(`select * from IDT_MULTI15880STROBJSTROBJ where col1 in ("dd", "dd") or col2 = 9923875910817805958 or col3 = "9994-11-11"`).Check(
+		testkit.Rows())
+	tk.MustQuery(`select * from IDT_MULTI15880STROBJSTROBJ where col1 in ("aa", "aa") or col2 = -9605492323393070105 or col3 = "0005-06-22"`).Check(
+		testkit.Rows("ee -9605492323393070105 0850-03-15"))
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0")) // unary operator '-' is not supported now.
+}
+
 func TestNonPreparedPlanCacheWithExplain(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)

planner/core/plan_cacheable_checker.go

@@ -252,31 +252,30 @@ type nonPreparedPlanCacheableChecker struct {
 // Enter implements Visitor interface.
 func (checker *nonPreparedPlanCacheableChecker) Enter(in ast.Node) (out ast.Node, skipChildren bool) {
 	switch node := in.(type) {
+	case *ast.SelectStmt, *ast.FieldList, *ast.SelectField, *ast.TableRefsClause, *ast.Join,
+		*ast.TableSource, *ast.ColumnNameExpr, *ast.ColumnName, *driver.ValueExpr, *ast.PatternInExpr:
+		return in, !checker.cacheable // skip child if un-cacheable
 	case *ast.BinaryOperationExpr:
 		if _, found := expression.NonPreparedPlanCacheableOp[node.Op.String()]; !found {
 			checker.cacheable = false
-			return in, true
 		}
-	case *ast.FuncCallExpr:
-		checker.cacheable = false
-		return in, true
+		return in, !checker.cacheable
 	case *ast.TableName:
 		if checker.schema != nil {
 			if isPartitionTable(checker.schema, node) {
 				checker.cacheable = false
-				return in, true
 			}
 			if hasGeneratedCol(checker.schema, node) {
 				checker.cacheable = false
-				return in, true
 			}
 			if isTempTable(checker.schema, node) {
 				checker.cacheable = false
-				return in, true
 			}
 		}
+		return in, !checker.cacheable
 	}
-	return in, false
+	checker.cacheable = false // unexpected cases
+	return in, !checker.cacheable
 }
 
 // Leave implements Visitor interface.