planner: check the ignore-plan-cache hint in insert-stmt (#40080) (#4…

…2712)

ref #39717, close #40079

executor/prepared_test.go

@@ -1204,6 +1204,29 @@ func TestPlanCacheOperators(t *testing.T) {
 	}
 }
 
+func TestIgnoreInsertStmt(t *testing.T) {
+	store, clean := testkit.CreateMockStore(t)
+	defer clean()
+	orgEnable := plannercore.PreparedPlanCacheEnabled()
+	defer func() {
+		plannercore.SetPreparedPlanCache(orgEnable)
+	}()
+	plannercore.SetPreparedPlanCache(true)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t (a int)")
+
+	// ignore-hint in insert-stmt can work
+	tk.MustExec("prepare st from 'insert into t select * from t'")
+	tk.MustExec("execute st")
+	tk.MustExec("execute st")
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustExec("prepare st from 'insert /*+ ignore_plan_cache() */ into t select * from t'")
+	tk.MustExec("execute st")
+	tk.MustExec("execute st")
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
+}
+
 func TestIssue28782(t *testing.T) {
 	store, clean := testkit.CreateMockStore(t)
 	defer clean()

planner/core/cacheable_checker.go

@@ -87,6 +87,24 @@ func (checker *cacheableChecker) Enter(in ast.Node) (out ast.Node, skipChildren
 				return in, true
 			}
 		}
+	case *ast.InsertStmt:
+		if node.Select == nil {
+			nRows := len(node.Lists)
+			nCols := 0
+			if len(node.Lists) > 0 { // avoid index-out-of-range
+				nCols = len(node.Lists[0])
+			}
+			if nRows*nCols > 200 { // to save memory
+				checker.cacheable = false
+				return in, true
+			}
+		}
+		for _, hints := range node.TableHints {
+			if hints.HintName.L == HintIgnorePlanCache {
+				checker.cacheable = false
+				return in, true
+			}
+		}
 	case *ast.VariableExpr, *ast.ExistsSubqueryExpr, *ast.SubqueryExpr:
 		checker.cacheable = false
 		return in, true