planner: enable cost model2 by default

executor/index_lookup_join_test.go

@@ -401,6 +401,7 @@ func TestIssue27138(t *testing.T) {
 
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
+	tk.MustExec("set tidb_cost_model_version=1")
 	tk.MustExec("drop table if exists t1,t2")
 
 	tk.MustExec("set @old_tidb_partition_prune_mode=@@tidb_partition_prune_mode")

executor/tiflashtest/tiflash_test.go

@@ -462,6 +462,7 @@ func TestPartitionTable(t *testing.T) {
 	store := testkit.CreateMockStore(t, withMockTiFlash(2))
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
+	tk.MustExec("set tidb_cost_model_version=1")
 	tk.MustExec("drop table if exists t")
 	tk.MustExec("drop table if exists t1")
 	tk.MustExec("drop table if exists t2")

planner/core/integration_test.go

@@ -6816,6 +6816,7 @@ func TestTiFlashPartitionTableScan(t *testing.T) {
 	store, dom := testkit.CreateMockStoreAndDomain(t)
 	tk := testkit.NewTestKit(t, store)
 	tk.MustExec("use test")
+	tk.MustExec("set tidb_cost_model_version=1")
 	tk.MustExec("set @@tidb_partition_prune_mode = 'dynamic'")
 	tk.MustExec("set @@tidb_isolation_read_engines = 'tiflash'")
 	tk.MustExec("set @@tidb_enforce_mpp = on")

planner/core/physical_plan_test.go

@@ -2476,6 +2476,7 @@ func TestCountStarForTikv(t *testing.T) {
 	tk := testkit.NewTestKit(t, store)
 
 	tk.MustExec("use test")
+	tk.MustExec("set tidb_cost_model_version=1")
 	tk.MustExec("create table t (a int(11) not null, b varchar(10) not null, c date not null, d char(1) not null, e bigint not null, f datetime not null, g bool not null, h bool )")
 	tk.MustExec("create table t_pick_row_id (a char(20) not null)")
 
@@ -2504,6 +2505,7 @@ func TestCountStarForTiFlash(t *testing.T) {
 	tk := testkit.NewTestKit(t, store)
 
 	tk.MustExec("use test")
+	tk.MustExec("set tidb_cost_model_version=1")
 	tk.MustExec("create table t (a int(11) not null, b varchar(10) not null, c date not null, d char(1) not null, e bigint not null, f datetime not null, g bool not null, h bool )")
 	tk.MustExec("create table t_pick_row_id (a char(20) not null)")
 

sessionctx/variable/tidb_vars.go

@@ -1094,7 +1094,7 @@ const (
 	DefTiDBForeignKeyChecks                      = false
 	DefTiDBAnalyzePartitionConcurrency           = 1
 	DefTiDBOptRangeMaxSize                       = 64 * int64(size.MB) // 64 MB
-	DefTiDBCostModelVer                          = 1
+	DefTiDBCostModelVer                          = 2
 	DefTiDBServerMemoryLimitSessMinSize          = 128 << 20
 	DefTiDBMergePartitionStatsConcurrency        = 1
 	DefTiDBServerMemoryLimitGCTrigger            = 0.7