From bc52ce07398ba5698be41fd68f34cdb59a059ff6 Mon Sep 17 00:00:00 2001
From: Yuanjia Zhang <zhangyuanjia@pingcap.com>
Date: Mon, 20 Feb 2023 22:09:13 +0800
Subject: [PATCH] planner: add more test cases for non-prep plan cache (#41608)

ref pingcap/tidb#36598
---
 planner/core/plan_cache_test.go        | 65 ++++++++++++++++++++++++++
 planner/core/plan_cacheable_checker.go |  7 +++
 2 files changed, 72 insertions(+)

diff --git a/planner/core/plan_cache_test.go b/planner/core/plan_cache_test.go
index 640bb2ee3b..261f2a099e 100644
--- a/planner/core/plan_cache_test.go
+++ b/planner/core/plan_cache_test.go
@@ -290,6 +290,71 @@ func TestNonPreparedPlanCacheFallback(t *testing.T) {
 	require.NotNil(t, err)
 }
 
+func TestNonPreparedPlanCacheFastPointGet(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec(`create table t (a int primary key, b int, unique key(b))`)
+	tk.MustExec(`set tidb_enable_non_prepared_plan_cache=1`)
+
+	// fast plans have a higher priority than non-prep cache plan
+	tk.MustQuery(`explain format='brief' select a from t where a in (1, 2)`).Check(testkit.Rows(
+		`Batch_Point_Get 2.00 root table:t handle:[1 2], keep order:false, desc:false`))
+	tk.MustQuery(`select a from t where a in (1, 2)`).Check(testkit.Rows())
+	tk.MustQuery(`select a from t where a in (1, 2)`).Check(testkit.Rows())
+	tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("0"))
+
+	tk.MustQuery(`explain format='brief' select b from t where b = 1`).Check(testkit.Rows(
+		`Point_Get 1.00 root table:t, index:b(b) `))
+	tk.MustQuery(`select b from t where b = 1`).Check(testkit.Rows())
+	tk.MustQuery(`select b from t where b = 1`).Check(testkit.Rows())
+	tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("0"))
+}
+
+func TestNonPreparedPlanCacheSetOperations(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec(`create table t (a int)`)
+	tk.MustExec(`set tidb_enable_non_prepared_plan_cache=1`)
+
+	// queries with set operations cannot hit the cache
+	for _, q := range []string{
+		`select * from t union select * from t`,
+		`select * from t union distinct select * from t`,
+		`select * from t union all select * from t`,
+		`select * from t except select * from t`,
+		`select * from t intersect select * from t`,
+	} {
+		tk.MustQuery(q).Check(testkit.Rows())
+		tk.MustQuery(q).Check(testkit.Rows())
+		tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("0"))
+	}
+}
+
+func TestNonPreparedPlanCacheSpecialTables(t *testing.T) {
+	store := testkit.CreateMockStore(t)
+	tk := testkit.NewTestKit(t, store)
+	tk.MustExec(`use test`)
+	tk.MustExec(`create table t (a int)`)
+	tk.MustExec(`create definer='root'@'localhost' view t_v as select * from t`)
+	tk.MustExec(`create table t_p (a int) partition by hash(a) partitions 4`)
+	tk.MustExec(`create temporary table t_t (a int)`)
+	tk.MustExec(`set tidb_enable_non_prepared_plan_cache=1`)
+
+	// queries that access partitioning tables, view, temporary tables or contain CTE cannot hit the cache.
+	for _, q := range []string{
+		`select * from t_v`,
+		`select * from t_p`,
+		`select * from t_t`,
+		`with t_cte as (select * from t) select * from t_cte`,
+	} {
+		tk.MustQuery(q).Check(testkit.Rows())
+		tk.MustQuery(q).Check(testkit.Rows())
+		tk.MustQuery(`select @@last_plan_from_cache`).Check(testkit.Rows("0"))
+	}
+}
+
 func TestNonPreparedPlanCacheBasically(t *testing.T) {
 	store := testkit.CreateMockStore(t)
 	tk := testkit.NewTestKit(t, store)
diff --git a/planner/core/plan_cacheable_checker.go b/planner/core/plan_cacheable_checker.go
index aee19c96a9..cfb38c2882 100644
--- a/planner/core/plan_cacheable_checker.go
+++ b/planner/core/plan_cacheable_checker.go
@@ -275,6 +275,9 @@ func (checker *nonPreparedPlanCacheableChecker) Enter(in ast.Node) (out ast.Node
 			if isTempTable(checker.schema, node) {
 				checker.cacheable = false
 			}
+			if isView(checker.schema, node) {
+				checker.cacheable = false
+			}
 		}
 		return in, !checker.cacheable
 	}
@@ -301,6 +304,10 @@ func hasGeneratedCol(schema infoschema.InfoSchema, tn *ast.TableName) bool {
 	return false
 }
 
+func isView(schema infoschema.InfoSchema, tn *ast.TableName) bool {
+	return schema.TableIsView(tn.Schema, tn.Name)
+}
+
 func isTempTable(schema infoschema.InfoSchema, tn *ast.TableName) bool {
 	tb, err := schema.TableByName(tn.Schema, tn.Name)
 	if err != nil {