planner: rebuild range when the range is empty

executor/prepared_serial_test.go

@@ -169,6 +169,102 @@ func TestPreparePlanCache4Blacklist(t *testing.T) {
 	tk.MustExec("ADMIN reload expr_pushdown_blacklist;")
 }
 
+func TestIssue29993(t *testing.T) {
+	store, dom, err := newStoreWithBootstrap()
+	require.NoError(t, err)
+	orgEnable := plannercore.PreparedPlanCacheEnabled()
+	defer func() {
+		plannercore.SetPreparedPlanCache(orgEnable)
+	}()
+	plannercore.SetPreparedPlanCache(true)
+	tk := testkit.NewTestKit(t, store)
+	defer func() {
+		dom.Close()
+		require.NoError(t, store.Close())
+	}()
+	tk.MustExec("use test")
+
+	// test PointGet + cluster index
+	tk.MustExec("set tidb_enable_clustered_index=on;")
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("CREATE TABLE `t` (`COL1` enum('a', 'b') NOT NULL PRIMARY KEY, col2 int) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;")
+	tk.MustExec("insert into t values('a', 1), ('b', 2);")
+	tk.MustExec("set @a='a', @b='b', @z='z';")
+	tk.MustExec(`prepare stmt from 'select col1 from t where col1 = ? and col2 in (1, 2);';`)
+	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("a"))
+	tk.MustQuery("execute stmt using @b").Check(testkit.Rows("b"))
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	// The length of range have been changed, so the plan can not be cached.
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	tkProcess := tk.Session().ShowProcess()
+	ps := []*util.ProcessInfo{tkProcess}
+	tk.Session().SetSessionManager(&mockSessionManager1{PS: ps})
+	// The plan should be tableDual.
+	tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).Check(testkit.Rows(
+		"Projection_4 0.00 root  test.t.col1",
+		"└─TableDual_5 0.00 root  rows:0"))
+
+	// test batchPointGet + cluster index
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("CREATE TABLE `t` (`COL1` enum('a', 'b') NOT NULL, col2 int, PRIMARY KEY(col1, col2)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;")
+	tk.MustExec("insert into t values('a', 1), ('b', 2);")
+	tk.MustExec("set @a='a', @b='b', @z='z';")
+	tk.MustExec(`prepare stmt from 'select col1 from t where (col1, col2) in ((?, 1));';`)
+	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("a"))
+	tk.MustQuery("execute stmt using @b").Check(testkit.Rows())
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	tkProcess = tk.Session().ShowProcess()
+	ps = []*util.ProcessInfo{tkProcess}
+	tk.Session().SetSessionManager(&mockSessionManager1{PS: ps})
+	tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).Check(testkit.Rows(
+		"Batch_Point_Get_1 1.00 root table:t, clustered index:PRIMARY(COL1, col2) keep order:false, desc:false"))
+
+	// test PointGet + non cluster index
+	tk.MustExec("set tidb_enable_clustered_index=off;")
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("CREATE TABLE `t` (`COL1` enum('a', 'b') NOT NULL PRIMARY KEY, col2 int) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;")
+	tk.MustExec("insert into t values('a', 1), ('b', 2);")
+	tk.MustExec("set @a='a', @b='b', @z='z';")
+	tk.MustExec(`prepare stmt from 'select col1 from t where col1 = ? and col2 in (1, 2);';`)
+	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("a"))
+	tk.MustQuery("execute stmt using @b").Check(testkit.Rows("b"))
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	// The length of range have been changed, so the plan can not be cached.
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	tkProcess = tk.Session().ShowProcess()
+	ps = []*util.ProcessInfo{tkProcess}
+	tk.Session().SetSessionManager(&mockSessionManager1{PS: ps})
+	// The plan should be tableDual.
+	tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).Check(testkit.Rows(
+		"Projection_4 0.00 root  test.t.col1",
+		"└─TableDual_5 0.00 root  rows:0"))
+
+	// test batchPointGet + non cluster index
+	tk.MustExec("drop table if exists t;")
+	tk.MustExec("CREATE TABLE `t` (`COL1` enum('a', 'b') NOT NULL, col2 int, PRIMARY KEY(col1, col2)) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;")
+	tk.MustExec("insert into t values('a', 1), ('b', 2);")
+	tk.MustExec("set @a='a', @b='b', @z='z';")
+	tk.MustExec(`prepare stmt from 'select col1 from t where (col1, col2) in ((?, 1));';`)
+	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("a"))
+	tk.MustQuery("execute stmt using @b").Check(testkit.Rows())
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("execute stmt using @z").Check(testkit.Rows())
+	tkProcess = tk.Session().ShowProcess()
+	ps = []*util.ProcessInfo{tkProcess}
+	tk.Session().SetSessionManager(&mockSessionManager1{PS: ps})
+	tk.MustQuery(fmt.Sprintf("explain for connection %d", tkProcess.ID)).Check(testkit.Rows(
+		"Batch_Point_Get_1 1.00 root table:t, index:PRIMARY(COL1, col2) keep order:false, desc:false"))
+}
+
 func TestPlanCacheClusterIndex(t *testing.T) {
 	store, dom, err := newStoreWithBootstrap()
 	require.NoError(t, err)

planner/core/common_plans.go

@@ -610,6 +610,9 @@ func (e *Execute) rebuildRange(p Plan) error {
 				if err != nil {
 					return err
 				}
+				if len(ranges.Ranges) == 0 || len(ranges.AccessConds) != len(x.AccessConditions) {
+					return errors.New("failed to rebuild range: the length of the range has changed")
+				}
 				for i := range x.IndexValues {
 					x.IndexValues[i] = ranges.Ranges[0].LowVal[i]
 				}
@@ -625,6 +628,9 @@ func (e *Execute) rebuildRange(p Plan) error {
 					if err != nil {
 						return err
 					}
+					if len(ranges) == 0 {
+						return errors.New("failed to rebuild range: the length of the range has changed")
+					}
 					x.Handle = kv.IntHandle(ranges[0].LowVal[0].GetInt64())
 				}
 			}
@@ -658,6 +664,9 @@ func (e *Execute) rebuildRange(p Plan) error {
 				if err != nil {
 					return err
 				}
+				if len(ranges.Ranges) != len(x.IndexValues) || len(ranges.AccessConds) != len(x.AccessConditions) {
+					return errors.New("failed to rebuild range: the length of the range has changed")
+				}
 				for i := range x.IndexValues {
 					for j := range ranges.Ranges[i].LowVal {
 						x.IndexValues[i][j] = ranges.Ranges[i].LowVal[j]
@@ -675,6 +684,9 @@ func (e *Execute) rebuildRange(p Plan) error {
 					if err != nil {
 						return err
 					}
+					if len(ranges) != len(x.Handles) {
+						return errors.New("failed to rebuild range: the length of the range has changed")
+					}
 					for i := range ranges {
 						x.Handles[i] = kv.IntHandle(ranges[i].LowVal[0].GetInt64())
 					}

planner/core/find_best_task.go

@@ -803,7 +803,11 @@ func (ds *DataSource) findBestTask(prop *property.PhysicalProperty, planCounter
 			continue
 		}
 		// if we already know the range of the scan is empty, just return a TableDual
-		if len(path.Ranges) == 0 && !ds.ctx.GetSessionVars().StmtCtx.UseCache {
+		if len(path.Ranges) == 0 {
+			// We should uncache the tableDual plan.
+			if expression.MaybeOverOptimized4PlanCache(ds.ctx, path.AccessConds) {
+				ds.ctx.GetSessionVars().StmtCtx.MaybeOverOptimized4PlanCache = true
+			}
 			dual := PhysicalTableDual{}.Init(ds.ctx, ds.stats, ds.blockOffset)
 			dual.SetSchema(ds.schema)
 			cntPlan += 1

planner/core/prepare_test.go

@@ -1850,8 +1850,11 @@ func (s *testPrepareSerialSuite) TestIssue28246(c *C) {
 	tk.MustExec("set @a=9223372036854775807, @b=1")
 	tk.MustExec(`prepare stmt from 'select min(col1) from PK_AUTO_RANDOM9111 where col1 > ?;';`)
 	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("<nil>"))
+	// The plan contains the tableDual, so it will not be cached.
+	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("<nil>"))
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
 	tk.MustQuery("execute stmt using @b").Check(testkit.Rows("9223372036854775807"))
-	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
+	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("0"))
 	tk.MustQuery("execute stmt using @a").Check(testkit.Rows("<nil>"))
 	tk.MustQuery("select @@last_plan_from_cache").Check(testkit.Rows("1"))
 }