Enable subquery materialization=ON by default.

mysql-test/r/derived_view.result

@@ -768,7 +768,7 @@ DROP TABLE t1;
 #
 # LP bug #803851: materialized view + IN->EXISTS                       
 #                 
-SET SESSION optimizer_switch='semijoin=off,derived_with_keys=on';
+SET SESSION optimizer_switch='semijoin=off,derived_with_keys=on,materialization=off';
 CREATE TABLE t1 (a int, b int);
 INSERT INTO t1 VALUES (2,2), (3,3), (1,1);
 CREATE TABLE t2 (a int);
@@ -1438,7 +1438,7 @@ KEY (c,a) , PRIMARY KEY (a)
 INSERT INTO t3 VALUES
 (14,4,'a'), (15,7,'b'), (16,4,'c'), (17,1,'d'), (18,9,'e'),
 (19,4,'f'), (20,8,'g');
-SET SESSION optimizer_switch='derived_merge=on,subquery_cache=off';
+SET SESSION optimizer_switch='derived_merge=on,subquery_cache=off,materialization=off';
 # The following two EXPLAINs must return the same execution plan
 EXPLAIN
 SELECT * FROM t1 , t2

mysql-test/r/group_by.result

@@ -1543,7 +1543,8 @@ EXPLAIN SELECT 1 FROM t1 WHERE a IN
 (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	PRIMARY,i2	PRIMARY	4	NULL	144	Using index
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where; FirstMatch(t1)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	4	func	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	
 CREATE TABLE t2 (a INT, b INT, KEY(a));
 INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
 EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2;

mysql-test/r/group_min_max.result

@@ -2401,8 +2401,9 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 EXPLAIN SELECT 1 FROM t1 AS t1_outer WHERE 
 a IN (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1_outer	index	NULL	a	10	NULL	15	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	10	NULL	1	Using index
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	8	Using where
+1	PRIMARY	t1_outer	ref	a	a	5	<subquery2>.max(b)	2	Using index
+2	SUBQUERY	t1	range	NULL	a	5	NULL	8	Using index for group-by
 EXPLAIN SELECT 1 FROM t1 AS t1_outer GROUP BY a HAVING 
 a > (SELECT max(b) FROM t1 GROUP BY a HAVING a < 2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra

mysql-test/r/subselect.result

@@ -2967,9 +2967,10 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cac
 explain extended SELECT one,two from t1 where ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = 'N');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; FirstMatch(t1)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	100.00	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`two` = `test`.`t1`.`two`) and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N'))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
@@ -3555,7 +3556,8 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	23	test.t1.a,test.t1.b	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3565,8 +3567,9 @@ AAA	8
 EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
+1	PRIMARY	t1	ALL	a	NULL	NULL	NULL	9	Using where
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	23	test.t1.a,test.t1.b	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4456,15 +4459,17 @@ INSERT INTO t1 VALUES (1),(2);
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
+1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	100.00	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having (1 = <ref_null_helper>(1)))))
+Note	1003	select 1 AS `1` from  <materialize> (select 1 from `test`.`t1` group by `test`.`t1`.`a`) join `test`.`t1` where (`<subquery2>`.`1` = 1)
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
+1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	100.00	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (1 = <ref_null_helper>(1)))))
+Note	1003	select 1 AS `1` from  <materialize> (select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a`) join `test`.`t1` where (`<subquery2>`.`1` = 1)
 DROP TABLE t1;
 #
 # Bug#45061: Incorrectly market field caused wrong result.
@@ -5146,10 +5151,11 @@ explain SELECT * FROM ot1,ot4
 WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
 FROM it2,it3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	Start temporary
-1	PRIMARY	it2	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
-1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	24	Using where
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	
+2	SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
 DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 #
 # Bug#729039: NULL keys used to evaluate subquery

mysql-test/r/subselect3.result

@@ -977,7 +977,7 @@ i1	i2
 # Baseline:
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	17
+Handler_read_rnd_next	18
 
 INSERT INTO t1 VALUES (NULL, NULL);
 FLUSH STATUS;
@@ -994,7 +994,7 @@ i1	i2
 # (read record from t1, but do not read from t2)
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	18
+Handler_read_rnd_next	19
 set @@optimizer_switch=@save_optimizer_switch2;
 DROP TABLE t1,t2;
 End of 5.1 tests
@@ -1025,6 +1025,8 @@ create table t11 select * from t1 where b = 67 AND (c IS NULL OR c > NOW()) orde
 create table t12 select * from t1 where b = 67 AND (c IS NULL OR c > NOW()) order by 3 desc;
 create table t21 select * from t1 where b = 67 AND (c IS NULL OR c > '2005-12-08') order by 3 asc;
 create table t22 select * from t1 where b = 67 AND (c IS NULL OR c > '2005-12-08') order by 3 desc;
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
 update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
@@ -1037,10 +1039,11 @@ select t21.* from t21,t22 where t21.a = t22.a and
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 a	b	c
 256	67	NULL
+set @@optimizer_switch=@save_optimizer_switch;
 drop table t1, t11, t12, t21, t22;
 create table t1(a int);
 insert into t1 values (0),(1);
-set @@optimizer_switch='firstmatch=off';
+set @@optimizer_switch='firstmatch=off,materialization=off';
 explain 
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -1114,6 +1117,8 @@ a
 18
 19
 set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
 explain select * from (select a from t0) X where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
@@ -1140,6 +1145,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index; FirstMatch(t1)
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t1, t3, t4;
+set @@optimizer_switch=@save_optimizer_switch;
 create table t1 (a int) as select * from t0 where a < 5;
 set @save_max_heap_table_size=@@max_heap_table_size;
 set @@optimizer_switch='firstmatch=off,materialization=off';
@@ -1169,8 +1175,9 @@ create table t3 ( a int , filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	End temporary
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 select * from t3 where a in (select a from t2);
 a	filler
 1	filler
@@ -1209,6 +1216,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
 drop table t1;
 set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
 create table t1 (a int);
 insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
 create table t2 as select * from t1;
@@ -1269,11 +1278,12 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	range	a	a	5	NULL	8	Using where; Using index; LooseScan
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t1,t2;
+set @@optimizer_switch=@save_optimizer_switch;
 create table t1 (a int, b int);
 insert into t1 select a,a from t0;
 create table t2 (a int, b int);
 insert into t2 select A.a + 10*B.a, A.a + 10*B.a from t0 A, t0 B;
-set @@optimizer_switch='firstmatch=off';
+set @@optimizer_switch='firstmatch=off,materialization=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Start temporary
@@ -1287,6 +1297,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 set @@optimizer_search_depth=@save_optimizer_search_depth;
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t0, t1, t2;
+set @@optimizer_switch='materialization=off';
 create table t0 (a decimal(4,2));
 insert into t0 values (10.24), (22.11);
 create table t1 as select * from t0;
@@ -1325,6 +1336,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	Y	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer (flat, BNL join)
 1	PRIMARY	Z	ALL	NULL	NULL	NULL	NULL	6	Using where; End temporary; Using join buffer (flat, BNL join)
 drop table t0,t1,t2;
+set @@optimizer_switch=@save_optimizer_switch;
 
 BUG#37842: Assertion in DsMrr_impl::dsmrr_init, at handler.cc:4307
 
@@ -1386,6 +1398,8 @@ postalStripped varchar(100)
 );
 insert into t3 values (1,1, 'foo'), (2,2,'bar');
 The following must be converted to a semi-join:
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=off';
 explain extended SELECT a.idIndividual FROM t1 a 
 WHERE a.idIndividual IN 
 (	SELECT c.idObj FROM t3 cona 
@@ -1398,6 +1412,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	a	eq_ref	PRIMARY	PRIMARY	4	test.c.idObj	1	100.00	Using index; End temporary
 Warnings:
 Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
+set @@optimizer_switch=@save_optimizer_switch;
 drop table t1,t2,t3;
 #
 # BUG#47367 Crash in Name_resolution_context::process_error

mysql-test/r/subselect3_jcl6.result

@@ -986,7 +986,7 @@ i1	i2
 # Baseline:
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	17
+Handler_read_rnd_next	18
 
 INSERT INTO t1 VALUES (NULL, NULL);
 FLUSH STATUS;
@@ -1003,7 +1003,7 @@ i1	i2
 # (read record from t1, but do not read from t2)
 SHOW STATUS LIKE '%Handler_read_rnd_next';
 Variable_name	Value
-Handler_read_rnd_next	18
+Handler_read_rnd_next	19
 set @@optimizer_switch=@save_optimizer_switch2;
 DROP TABLE t1,t2;
 End of 5.1 tests
@@ -1034,6 +1034,8 @@ create table t11 select * from t1 where b = 67 AND (c IS NULL OR c > NOW()) orde
 create table t12 select * from t1 where b = 67 AND (c IS NULL OR c > NOW()) order by 3 desc;
 create table t21 select * from t1 where b = 67 AND (c IS NULL OR c > '2005-12-08') order by 3 asc;
 create table t22 select * from t1 where b = 67 AND (c IS NULL OR c > '2005-12-08') order by 3 desc;
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
 update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
@@ -1046,10 +1048,11 @@ select t21.* from t21,t22 where t21.a = t22.a and
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 a	b	c
 256	67	NULL
+set @@optimizer_switch=@save_optimizer_switch;
 drop table t1, t11, t12, t21, t22;
 create table t1(a int);
 insert into t1 values (0),(1);
-set @@optimizer_switch='firstmatch=off';
+set @@optimizer_switch='firstmatch=off,materialization=off';
 explain 
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -1123,6 +1126,8 @@ a
 18
 19
 set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
 explain select * from (select a from t0) X where a in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
@@ -1149,6 +1154,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t1.c	1	Using index; FirstMatch(t1)
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t1, t3, t4;
+set @@optimizer_switch=@save_optimizer_switch;
 create table t1 (a int) as select * from t0 where a < 5;
 set @save_max_heap_table_size=@@max_heap_table_size;
 set @@optimizer_switch='firstmatch=off,materialization=off';
@@ -1178,8 +1184,9 @@ create table t3 ( a int , filler char(100), key(a));
 insert into t3 select A.a + 10*B.a, 'filler' from t0 A, t0 B;
 explain select * from t3 where a in (select a from t2) and (a > 5 or a < 10);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
+1	PRIMARY	t3	ref	a	a	5	test.t2.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 select * from t3 where a in (select a from t2);
 a	filler
 1	filler
@@ -1218,6 +1225,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	hash_ALL	NULL	#hash#$hj	6	test.t1.a	2	Using where; End temporary; Using join buffer (flat, BNLH join)
 drop table t1;
 set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
 create table t1 (a int);
 insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
 create table t2 as select * from t1;
@@ -1278,11 +1287,12 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	range	a	a	5	NULL	8	Using where; Using index; LooseScan
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	100	Using where; Using join buffer (flat, BNL join)
 drop table t1,t2;
+set @@optimizer_switch=@save_optimizer_switch;
 create table t1 (a int, b int);
 insert into t1 select a,a from t0;
 create table t2 (a int, b int);
 insert into t2 select A.a + 10*B.a, A.a + 10*B.a from t0 A, t0 B;
-set @@optimizer_switch='firstmatch=off';
+set @@optimizer_switch='firstmatch=off,materialization=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
@@ -1296,6 +1306,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 set @@optimizer_search_depth=@save_optimizer_search_depth;
 set @@optimizer_switch=@save_optimizer_switch;
 drop table t0, t1, t2;
+set @@optimizer_switch='materialization=off';
 create table t0 (a decimal(4,2));
 insert into t0 values (10.24), (22.11);
 create table t1 as select * from t0;
@@ -1334,6 +1345,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	Y	hash_ALL	NULL	#hash#$hj	5	test.t1.b	6	Using where; Using join buffer (incremental, BNLH join)
 1	PRIMARY	Z	hash_ALL	NULL	#hash#$hj	5	test.t1.c	6	Using where; End temporary; Using join buffer (incremental, BNLH join)
 drop table t0,t1,t2;
+set @@optimizer_switch=@save_optimizer_switch;
 
 BUG#37842: Assertion in DsMrr_impl::dsmrr_init, at handler.cc:4307
 
@@ -1395,6 +1407,8 @@ postalStripped varchar(100)
 );
 insert into t3 values (1,1, 'foo'), (2,2,'bar');
 The following must be converted to a semi-join:
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=off';
 explain extended SELECT a.idIndividual FROM t1 a 
 WHERE a.idIndividual IN 
 (	SELECT c.idObj FROM t3 cona 
@@ -1407,6 +1421,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	a	eq_ref	PRIMARY	PRIMARY	4	test.c.idObj	1	100.00	Using index; End temporary
 Warnings:
 Note	1003	select `test`.`a`.`idIndividual` AS `idIndividual` from `test`.`t1` `a` semi join (`test`.`t3` `cona` join `test`.`t2` `c`) where ((`test`.`c`.`idContact` = `test`.`cona`.`idContact`) and (`test`.`a`.`idIndividual` = `test`.`c`.`idObj`) and (`test`.`cona`.`postalStripped` = 'T2H3B2'))
+set @@optimizer_switch=@save_optimizer_switch;
 drop table t1,t2,t3;
 #
 # BUG#47367 Crash in Name_resolution_context::process_error

mysql-test/r/subselect4.result

@@ -117,6 +117,8 @@ CREATE TABLE t4 ( a INT );
 INSERT INTO t4 VALUES (1), (2), (3);
 CREATE TABLE t5 ( a INT );
 INSERT INTO t5 VALUES (NULL), (2);
+SET @old_optimizer_switch = @@session.optimizer_switch;
+SET SESSION optimizer_switch = 'materialization=off,in_to_exists=on,semijoin=off';
 EXPLAIN
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT c, d FROM t2 );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
@@ -188,6 +190,7 @@ SELECT * FROM t1 WHERE NULL NOT IN ( SELECT c FROM t2 WHERE c = 1 AND c <> 1 );
 a	b
 1	NULL
 2	NULL
+SET SESSION optimizer_switch = @old_optimizer_switch;
 DROP TABLE t1, t2, t3, t4, t5;
 #
 # Bug#58207: invalid memory reads when using default column value and 
@@ -1242,17 +1245,19 @@ EXPLAIN
 SELECT * FROM (t2 LEFT JOIN t1 ON t1.c1) LEFT JOIN t3 on t3.c1 WHERE 's' IN (SELECT c1 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	0	const row not found
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary; End temporary
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
 1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	3	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 SELECT * FROM (t2 LEFT JOIN t1 ON t1.c1) LEFT JOIN t3 on t3.c1 WHERE 's' IN (SELECT c1 FROM t2);
 c1	c1	c1
 EXPLAIN
 SELECT * FROM t4 LEFT JOIN t2 ON t4.c1 WHERE 's' IN (SELECT c1 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary; End temporary
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 1	PRIMARY	t4	index	NULL	PRIMARY	3	NULL	2	Using index; Using join buffer (flat, BNL join)
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where
 SELECT * FROM t4 LEFT JOIN t2 ON t4.c1 WHERE 's' IN (SELECT c1 FROM t2);
 c1	c1
 drop table t1, t2, t3, t4;

mysql-test/r/subselect_cache.result

@@ -1338,11 +1338,11 @@ Subquery_cache_miss	0
 show status like '%Handler_read%';
 Variable_name	Value
 Handler_read_first	0
-Handler_read_key	0
+Handler_read_key	11
 Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	0
-Handler_read_rnd_next	188
+Handler_read_rnd_next	145
 set optimizer_switch='subquery_cache=on';
 flush status;
 select a, b , exists (select * from t2 where b=d) as SUBSE, b in (select d from t2) as SUBSI, (select d from t2 where b=c) SUBSR from t1;
@@ -1366,11 +1366,11 @@ Subquery_cache_miss	18
 show status like '%Handler_read%';
 Variable_name	Value
 Handler_read_first	0
-Handler_read_key	27
+Handler_read_key	32
 Handler_read_next	0
 Handler_read_prev	0
 Handler_read_rnd	0
-Handler_read_rnd_next	102
+Handler_read_rnd_next	84
 #several subqueries (several levels)
 set optimizer_switch='subquery_cache=off';
 flush status;

mysql-test/r/subselect_extra.result

@@ -304,7 +304,8 @@ EXPLAIN SELECT 1 FROM t1 WHERE a IN
 (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	PRIMARY,i2	PRIMARY	4	NULL	144	Using index
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where; FirstMatch(t1)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	4	func	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	
 CREATE TABLE t2 (a INT, b INT, KEY(a));
 INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
 EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2;

mysql-test/r/subselect_extra_no_semijoin.result

@@ -308,7 +308,7 @@ EXPLAIN SELECT 1 FROM t1 WHERE a IN
 (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	NULL	PRIMARY	4	NULL	144	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	
 CREATE TABLE t2 (a INT, b INT, KEY(a));
 INSERT INTO t2 VALUES (1, 1), (2, 2), (3,3), (4,4);
 EXPLAIN SELECT a, SUM(b) FROM t2 GROUP BY a LIMIT 2;
@@ -321,7 +321,7 @@ EXPLAIN SELECT 1 FROM t2 WHERE a IN
 (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	index	NULL	a	5	NULL	4	Using where; Using index
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	144	
 DROP TABLE t1, t2;
 # 
 # From derived_view.test
@@ -346,9 +346,9 @@ WHERE t.a IN (SELECT b FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-3	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
+3	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0))))
+Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,0 in ( <materialize> (select 0 from `test`.`t1` ), <primary_index_lookup>(0 in <temporary table> on distinct_key where ((0 = `<subquery3>`.`b`))))))
 SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
 WHERE t.a IN (SELECT b FROM t1);
 a	a	b
@@ -359,9 +359,9 @@ WHERE t.a IN (SELECT b FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
+2	SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0))))
+Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,0 in ( <materialize> (select 0 from `test`.`t1` ), <primary_index_lookup>(0 in <temporary table> on distinct_key where ((0 = `<subquery2>`.`b`))))))
 DROP VIEW v1;
 DROP TABLE t1,t2;
 #

mysql-test/r/subselect_mat_cost_bugs.result

@@ -292,7 +292,7 @@ insert into t2 values (0,0,0,'filler'),(0,1,1,'filler'),(0,2,2,'filler'),(0,3,3,
 create index key1 on t2 (kp1, kp2);
 create index key2 on t2 (kp1);
 create index key3 on t2 (kp2);
-set session optimizer_switch='default';
+SET @@optimizer_switch='materialization=off,semijoin=off,in_to_exists=on';
 analyze table t2;
 Table	Op	Msg_type	Msg_text
 test.t2	analyze	status	OK
@@ -303,6 +303,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 2	DEPENDENT SUBQUERY	t2	index_subquery	key1,key2,key3	key1	10	func,const	1	Using where
 select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
 c1
+set @@optimizer_switch='default';
 drop table t1, t2;
 #
 # LP BUG#800679: Assertion `outer_join->table_count > 0' failed in

mysql-test/r/subselect_no_mat.result

 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'
-0
+1
 set optimizer_switch='materialization=off';
 set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t11,t12;
@@ -5645,4 +5645,4 @@ set optimizer_switch=@subselect_tmp;
 set optimizer_switch=default;
 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'
-0
+1

mysql-test/r/subselect_no_scache.result

@@ -2971,9 +2971,10 @@ Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<in_optim
 explain extended SELECT one,two from t1 where ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = 'N');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where; FirstMatch(t1)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	10	func,func	1	100.00	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	9	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`two` = `test`.`t1`.`two`) and (`test`.`t2`.`one` = `test`.`t1`.`one`) and (`test`.`t2`.`flag` = 'N'))
+Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`flag` = 'N'))
 explain extended SELECT one,two,ROW(one,two) IN (SELECT one,two FROM t2 WHERE flag = '0' group by one,two) as 'test' from t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	8	100.00	
@@ -3559,7 +3560,8 @@ EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	23	test.t1.a,test.t1.b	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 ALTER TABLE t1 ADD INDEX(a);
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 a	b
@@ -3569,8 +3571,9 @@ AAA	8
 EXPLAIN
 SELECT * FROM t1 WHERE (a,b) = ANY (SELECT a, max(b) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	9	Using where
-2	DEPENDENT SUBQUERY	t1	index	NULL	a	8	NULL	1	
+1	PRIMARY	t1	ALL	a	NULL	NULL	NULL	9	Using where
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	23	test.t1.a,test.t1.b	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	9	Using temporary
 DROP TABLE t1;
 create table t1( f1 int,f2 int);
 insert into t1 values (1,1),(2,2);
@@ -4460,15 +4463,17 @@ INSERT INTO t1 VALUES (1),(2);
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
+1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	100.00	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <in_optimizer>(1,<exists>(select 1 from `test`.`t1` group by `test`.`t1`.`a` having (1 = <ref_null_helper>(1))))
+Note	1003	select 1 AS `1` from  <materialize> (select 1 from `test`.`t1` group by `test`.`t1`.`a`) join `test`.`t1` where (`<subquery2>`.`1` = 1)
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT 1 FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
+1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	100.00	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
-Note	1003	select 1 AS `1` from `test`.`t1` where <in_optimizer>(1,<exists>(select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (1 = <ref_null_helper>(1))))
+Note	1003	select 1 AS `1` from  <materialize> (select 1 from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a`) join `test`.`t1` where (`<subquery2>`.`1` = 1)
 DROP TABLE t1;
 #
 # Bug#45061: Incorrectly market field caused wrong result.
@@ -5150,10 +5155,11 @@ explain SELECT * FROM ot1,ot4
 WHERE (ot1.a,ot4.a) IN (SELECT it2.a,it3.a
 FROM it2,it3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	Start temporary
-1	PRIMARY	it2	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
-1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	24	Using where
+1	PRIMARY	ot4	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it2	ALL	NULL	NULL	NULL	NULL	4	
+2	SUBQUERY	it3	ALL	NULL	NULL	NULL	NULL	6	Using join buffer (flat, BNL join)
 DROP TABLE IF EXISTS ot1, ot4, it2, it3;
 #
 # Bug#729039: NULL keys used to evaluate subquery

mysql-test/r/subselect_sj.result

@@ -79,18 +79,18 @@ id	select_type	tABle	type	possiBle_keys	key	key_len	ref	rows	filtered	ExtrA
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	DEPENDENT SUBQUERY	t10	unique_suBquery	PRIMARY	PRIMARY	4	func	1	100.00	Using index
+2	SUBQUERY	t10	index	PRIMARY	PRIMARY	4	NULL	10	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`A`.`A` AS `A`,`test`.`A`.`B` AS `B`,`test`.`B`.`A` AS `A`,`test`.`B`.`B` AS `B` from `test`.`t1` left join (`test`.`t2` `A` join `test`.`t2` `B`) on((<in_optimizer>(`test`.`B`.`A`,<exists>(<primAry_index_lookup>(<cAche>(`test`.`B`.`A`) in t10 on PRIMARY))) And (`test`.`A`.`A` = `test`.`t1`.`A`))) where 1
+Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`A`.`A` AS `A`,`test`.`A`.`B` AS `B`,`test`.`B`.`A` AS `A`,`test`.`B`.`B` AS `B` from `test`.`t1` left join (`test`.`t2` `A` join `test`.`t2` `B`) on((<in_optimizer>(`test`.`B`.`A`,`test`.`B`.`A` in ( <mAteriAlize> (select `test`.`t10`.`pk` from `test`.`t10` ), <primAry_index_lookup>(`test`.`B`.`A` in <temporAry tABle> on distinct_key where ((`test`.`B`.`A` = `<suBquery2>`.`pk`))))) And (`test`.`A`.`A` = `test`.`t1`.`A`))) where 1
 t2 should be wrapped into OJ-nest, so we have "t1 LJ (t2 J t10)"
 explAin extended
 select * from t1 left join t2 on (t2.A= t1.A And t2.A in (select pk from t10));
 id	select_type	tABle	type	possiBle_keys	key	key_len	ref	rows	filtered	ExtrA
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where
-2	DEPENDENT SUBQUERY	t10	unique_suBquery	PRIMARY	PRIMARY	4	func	1	100.00	Using index
+2	SUBQUERY	t10	index	PRIMARY	PRIMARY	4	NULL	10	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`t2`.`A` AS `A`,`test`.`t2`.`B` AS `B` from `test`.`t1` left join `test`.`t2` on((<in_optimizer>(`test`.`t2`.`A`,<exists>(<primAry_index_lookup>(<cAche>(`test`.`t2`.`A`) in t10 on PRIMARY))) And (`test`.`t2`.`A` = `test`.`t1`.`A`))) where 1
+Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`t2`.`A` AS `A`,`test`.`t2`.`B` AS `B` from `test`.`t1` left join `test`.`t2` on((<in_optimizer>(`test`.`t2`.`A`,`test`.`t2`.`A` in ( <mAteriAlize> (select `test`.`t10`.`pk` from `test`.`t10` ), <primAry_index_lookup>(`test`.`t2`.`A` in <temporAry tABle> on distinct_key where ((`test`.`t2`.`A` = `<suBquery2>`.`pk`))))) And (`test`.`t2`.`A` = `test`.`t1`.`A`))) where 1
 we shouldn't flatten if we're going to get a join of > MAX_TABLES.
 explain select * from 
 t1 s00, t1 s01,  t1 s02, t1 s03, t1 s04,t1 s05,t1 s06,t1 s07,t1 s08,t1 s09,
@@ -724,9 +724,10 @@ SELECT int_key FROM ot1
 WHERE int_nokey IN (SELECT it2.int_key
 FROM it1 LEFT JOIN it2 ON it2.datetime_key);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	it1	index	NULL	int_key	4	NULL	2	Using index; Start temporary
-1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	20	Using join buffer (flat, BNL join)
-1	PRIMARY	it2	ALL	int_key,datetime_key	NULL	NULL	NULL	20	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	11	
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	20	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it1	index	NULL	int_key	4	NULL	2	Using index
+2	SUBQUERY	it2	ALL	int_key,datetime_key	NULL	NULL	NULL	20	Using where; Using join buffer (flat, BNL join)
 DROP TABLE ot1, it1, it2;
 # End of BUG#38075
 #
@@ -798,9 +799,10 @@ INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii','iiii','ffff','ffff','ffff','f
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	13	func,func	1	100.00	
+2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Rowid-ordered scan
 Warnings:
-Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`pk` > 0))
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 pk
 2
@@ -966,9 +968,10 @@ FROM t1
 WHERE `varchar_nokey`  < 'n' XOR `pk`  )   ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	18	100.00	
-1	PRIMARY	t1	ref	varchar_key	varchar_key	3	test.t2.varchar_nokey	2	100.00	Using where; FirstMatch(t2)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	8	func,func	1	100.00	
+2	SUBQUERY	t1	ALL	varchar_key	NULL	NULL	NULL	15	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_key` = `test`.`t2`.`varchar_nokey`) and (`test`.`t1`.`varchar_nokey` = `test`.`t2`.`varchar_nokey`) and ((`test`.`t2`.`varchar_nokey` < 'n') xor `test`.`t1`.`pk`))
+Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_nokey` = `test`.`t1`.`varchar_key`) and ((`test`.`t1`.`varchar_key` < 'n') xor `test`.`t1`.`pk`))
 SELECT varchar_nokey
 FROM t2  
 WHERE ( `varchar_nokey`  , `varchar_nokey`  )  IN (  
@@ -1046,9 +1049,11 @@ WHERE  t2.val LIKE 'a%' OR t2.val LIKE 'e%')
 AND t1.val IN (SELECT t3.val FROM t3
 WHERE  t3.val LIKE 'a%' OR t3.val LIKE 'e%');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	Start temporary
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	
+1	PRIMARY	<subquery3>	eq_ref	distinct_key	distinct_key	14	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	14	func	1	
+3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 SELECT *
 FROM t1
 WHERE t1.val IN (SELECT t2.val FROM t2
@@ -1266,10 +1271,12 @@ explain
 select * from t1 A, t1 B
 where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	Start temporary
+1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery3>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	C	ALL	NULL	NULL	NULL	NULL	3	
+3	SUBQUERY	D	ALL	NULL	NULL	NULL	NULL	3	
 drop table t1, t2;
 # 
 # BUG#784441: Abort on semijoin with a view as the inner table
@@ -1284,7 +1291,7 @@ SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
-2	DEPENDENT SUBQUERY	<derived3>	system	NULL	NULL	NULL	NULL	1	
+2	SUBQUERY	<derived3>	system	NULL	NULL	NULL	NULL	1	
 3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
 a	a
@@ -1377,9 +1384,10 @@ insert into t3 values('three'),( 'four');
 insert into t3 values('three'),( 'four');
 explain select * from t3 where t3.b in (select t2.b from t1 left join t2 on t1.a=t2.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Start temporary
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	8	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
 select * from t3 where t3.b in (select t2.b from t1 left join t2 on t1.a=t2.a);
 b
 drop table t1, t2, t3;

mysql-test/r/subselect_sj2.result

@@ -46,8 +46,9 @@ a	b
 19	14
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
-1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	End temporary
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	3	
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
 select * from t2 where b in (select a from t1);
 a	b
 1	1
@@ -65,8 +66,9 @@ insert into t3 select a,a, a,a,a from t0;
 insert into t3 select a,a, a+100,a+100,a+100 from t0;
 explain select * from t3 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
-1	PRIMARY	t3	ref	b	b	5	test.t1.a	1	End temporary
+1	PRIMARY	t3	ALL	b	NULL	NULL	NULL	20	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
 select * from t3 where b in (select a from t1);
 a	b	pk1	pk2	pk3
 1	1	1	1	1
@@ -90,8 +92,9 @@ A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a
 from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
-1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	End temporary
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
+1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	
+2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
 set @save_ecp= @@engine_condition_pushdown;
 set engine_condition_pushdown=0;
 select * from t3 where b in (select A.a+B.a from t0 A, t0 B where B.a<5);
@@ -143,8 +146,9 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Start temporary
-1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	32	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -176,7 +180,8 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	32	Using where; FirstMatch(ot)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -209,8 +214,9 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Start temporary
-1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
+1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	52	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -242,7 +248,8 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	52	Using where; FirstMatch(ot)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -282,9 +289,10 @@ from t0 where a in
 (select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	t1	index	a	a	5	NULL	10	Using where; Using index
-1	PRIMARY	t2	ref	a	a	5	test.t1.a	1	Using index
-1	PRIMARY	t3	ref	a	a	5	test.t1.a	1	Using index; FirstMatch(t0)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	9	func	1	Using where
+2	SUBQUERY	t1	index	a	a	5	NULL	10	Using where; Using index
+2	SUBQUERY	t2	ref	a	a	5	test.t1.a	1	Using index
+2	SUBQUERY	t3	ref	a	a	5	test.t1.a	1	Using index
 drop table t0, t1,t2,t3;
 CREATE TABLE t1 (
 ID int(11) NOT NULL auto_increment,
@@ -361,7 +369,8 @@ WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
-1	PRIMARY	t2	ref	CountryCode	CountryCode	3	test.t1.Code	18	Using where; FirstMatch(t1)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
+2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
 SELECT Name FROM t1 
 WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
@@ -596,7 +605,7 @@ select * from t1 left join t2 on (t2.a= t1.a and t2.a in (select pk from t3));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	Using where
-2	DEPENDENT SUBQUERY	t3	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index
+2	SUBQUERY	t3	index	PRIMARY	PRIMARY	4	NULL	10	Using index
 drop table t0, t1, t2, t3;
 create table t1 (a int);
 insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
@@ -708,8 +717,9 @@ alter table t3 add primary key(id), add key(a);
 The following must use loose index scan over t3, key a:
 explain select count(a) from t2 where a in ( SELECT  a FROM t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	index	a	a	5	NULL	1000	Using where; Using index
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	30	Using index; FirstMatch(t2)
+1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
 select count(a) from t2 where a in ( SELECT  a FROM t3);
 count(a)
 1000
@@ -864,10 +874,11 @@ EXPLAIN
 SELECT * FROM t3 LEFT JOIN (v1,t2) ON t3.a = t2.a
 WHERE t3.b IN (SELECT b FROM t4);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	1	Start temporary
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	1	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	1	Using where
 1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	
-1	PRIMARY	t4	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	2	
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	1	
 SELECT * FROM t3 LEFT JOIN (v1,t2) ON t3.a = t2.a
 WHERE t3.b IN (SELECT b FROM t4);

mysql-test/r/subselect_sj2_jcl6.result

@@ -55,8 +55,9 @@ a	b
 19	14
 explain select * from t2 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
-1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	3	
+1	PRIMARY	t2	ref	b	b	5	test.t1.a	2	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where
 select * from t2 where b in (select a from t1);
 a	b
 1	1
@@ -74,8 +75,9 @@ insert into t3 select a,a, a,a,a from t0;
 insert into t3 select a,a, a+100,a+100,a+100 from t0;
 explain select * from t3 where b in (select a from t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	Using where; Start temporary
-1	PRIMARY	t3	ref	b	b	5	test.t1.a	1	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	t3	ALL	b	NULL	NULL	NULL	20	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	3	
 select * from t3 where b in (select a from t1);
 a	b	pk1	pk2	pk3
 1	1	1	1	1
@@ -99,8 +101,9 @@ A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a, A.a + 10*B.a
 from t0 A, t0 B where B.a <5;
 explain select * from t3 where b in (select a from t0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where; Start temporary
-1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	End temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	10	
+1	PRIMARY	t3	ref	b	b	5	test.t0.a	1	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+2	SUBQUERY	t0	ALL	NULL	NULL	NULL	NULL	10	Using where
 set @save_ecp= @@engine_condition_pushdown;
 set engine_condition_pushdown=0;
 select * from t3 where b in (select A.a+B.a from t0 A, t0 B where B.a<5);
@@ -152,8 +155,9 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Using where; Start temporary
-1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	32	Using where; End temporary; Using join buffer (flat, BNLH join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
+1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	32	Using where; Using join buffer (flat, BNLH join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	Using where
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -185,7 +189,8 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	32	Using where; FirstMatch(ot); Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	32	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -209,8 +214,8 @@ a	mid(filler1, 1,10)	length(filler1)=length(filler2)
 16	filler1234	1
 17	filler1234	1
 18	filler1234	1
-3	duplicate 	1
 19	filler1234	1
+3	duplicate 	1
 19	duplicate 	1
 insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
 insert into t1 select a+20, 'filler123456', 'filler123456' from t0;
@@ -218,8 +223,9 @@ explain select
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	22	Using where; Start temporary
-1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	52	Using where; End temporary; Using join buffer (flat, BNLH join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	22	
+1	PRIMARY	ot	hash_ALL	NULL	#hash#$hj	5	test.it.a	52	Using where; Using join buffer (flat, BNLH join)
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	22	Using where
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) as Z 
 from t1 ot where a in (select a from t2 it);
@@ -251,7 +257,8 @@ a, mid(filler1, 1,10), length(filler1)=length(filler2)
 from t2 ot where a in (select a from t1 it);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	ot	ALL	NULL	NULL	NULL	NULL	22	
-1	PRIMARY	it	ALL	NULL	NULL	NULL	NULL	52	Using where; FirstMatch(ot); Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	it	ALL	NULL	NULL	NULL	NULL	52	
 select 
 a, mid(filler1, 1,10), length(filler1)=length(filler2) 
 from t2 ot where a in (select a from t1 it);
@@ -275,8 +282,8 @@ a	mid(filler1, 1,10)	length(filler1)=length(filler2)
 16	filler1234	1
 17	filler1234	1
 18	filler1234	1
-3	duplicate 	1
 19	filler1234	1
+3	duplicate 	1
 19	duplicate 	1
 drop table t1, t2;
 create table t1 (a int, b int, key(a));
@@ -291,9 +298,10 @@ from t0 where a in
 (select t2.a+t3.a from t1 left join (t2 join t3) on t2.a=t1.a and t3.a=t1.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	10	
-1	PRIMARY	t1	index	a	a	5	NULL	10	Using where; Using index
-1	PRIMARY	t2	ref	a	a	5	test.t1.a	1	Using index
-1	PRIMARY	t3	ref	a	a	5	test.t1.a	1	Using index; FirstMatch(t0)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	9	func	1	Using where
+2	SUBQUERY	t1	index	a	a	5	NULL	10	Using where; Using index
+2	SUBQUERY	t2	ref	a	a	5	test.t1.a	1	Using index
+2	SUBQUERY	t3	ref	a	a	5	test.t1.a	1	Using index
 drop table t0, t1,t2,t3;
 CREATE TABLE t1 (
 ID int(11) NOT NULL auto_increment,
@@ -370,7 +378,8 @@ WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	PRIMARY	NULL	NULL	NULL	31	
-1	PRIMARY	t2	ref	CountryCode	CountryCode	3	test.t1.Code	18	Using where; FirstMatch(t1); Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	3	func	1	
+2	SUBQUERY	t2	ALL	CountryCode	NULL	NULL	NULL	545	Using where
 SELECT Name FROM t1 
 WHERE t1.Code IN (
 SELECT t2.CountryCode FROM t2 WHERE Population > 5000000);
@@ -607,7 +616,7 @@ select * from t1 left join t2 on (t2.a= t1.a and t2.a in (select pk from t3));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	
 1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	3	Using where; Using join buffer (flat, BNLH join)
-2	DEPENDENT SUBQUERY	t3	unique_subquery	PRIMARY	PRIMARY	4	func	1	Using index
+2	SUBQUERY	t3	index	PRIMARY	PRIMARY	4	NULL	10	Using index
 drop table t0, t1, t2, t3;
 create table t1 (a int);
 insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
@@ -719,8 +728,9 @@ alter table t3 add primary key(id), add key(a);
 The following must use loose index scan over t3, key a:
 explain select count(a) from t2 where a in ( SELECT  a FROM t3);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	index	a	a	5	NULL	1000	Using where; Using index
-1	PRIMARY	t3	ref	a	a	5	test.t2.a	30	Using index; FirstMatch(t2)
+1	PRIMARY	t2	index	a	a	5	NULL	1000	Using index
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	t3	index	a	a	5	NULL	30000	Using index
 select count(a) from t2 where a in ( SELECT  a FROM t3);
 count(a)
 1000
@@ -875,10 +885,11 @@ EXPLAIN
 SELECT * FROM t3 LEFT JOIN (v1,t2) ON t3.a = t2.a
 WHERE t3.b IN (SELECT b FROM t4);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	1	Using where; Start temporary
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	1	
 1	PRIMARY	t2	hash_ALL	NULL	#hash#$hj	5	test.t3.a	1	Using where; Using join buffer (flat, BNLH join)
 1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (incremental, BNL join)
-1	PRIMARY	t4	hash_ALL	NULL	#hash#$hj	5	test.t3.b	2	Using where; End temporary; Using join buffer (incremental, BNLH join)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	2	
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	1	
 SELECT * FROM t3 LEFT JOIN (v1,t2) ON t3.a = t2.a
 WHERE t3.b IN (SELECT b FROM t4);

mysql-test/r/subselect_sj2_mat.result

@@ -893,4 +893,4 @@ set optimizer_switch=@subselect_sj2_tmp;
 set optimizer_switch=default;
 select @@optimizer_switch like '%materialization=on%';
 @@optimizer_switch like '%materialization=on%'
-0
+1

mysql-test/r/subselect_sj_jcl6.result

@@ -90,18 +90,18 @@ id	select_type	tABle	type	possiBle_keys	key	key_len	ref	rows	filtered	ExtrA
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join Buffer (flAt, BNL join)
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join Buffer (incrementAl, BNL join)
-2	DEPENDENT SUBQUERY	t10	unique_suBquery	PRIMARY	PRIMARY	4	func	1	100.00	Using index
+2	SUBQUERY	t10	index	PRIMARY	PRIMARY	4	NULL	10	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`A`.`A` AS `A`,`test`.`A`.`B` AS `B`,`test`.`B`.`A` AS `A`,`test`.`B`.`B` AS `B` from `test`.`t1` left join (`test`.`t2` `A` join `test`.`t2` `B`) on((<in_optimizer>(`test`.`B`.`A`,<exists>(<primAry_index_lookup>(<cAche>(`test`.`B`.`A`) in t10 on PRIMARY))) And (`test`.`A`.`A` = `test`.`t1`.`A`))) where 1
+Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`A`.`A` AS `A`,`test`.`A`.`B` AS `B`,`test`.`B`.`A` AS `A`,`test`.`B`.`B` AS `B` from `test`.`t1` left join (`test`.`t2` `A` join `test`.`t2` `B`) on((<in_optimizer>(`test`.`B`.`A`,`test`.`B`.`A` in ( <mAteriAlize> (select `test`.`t10`.`pk` from `test`.`t10` ), <primAry_index_lookup>(`test`.`B`.`A` in <temporAry tABle> on distinct_key where ((`test`.`B`.`A` = `<suBquery2>`.`pk`))))) And (`test`.`A`.`A` = `test`.`t1`.`A`))) where 1
 t2 should be wrapped into OJ-nest, so we have "t1 LJ (t2 J t10)"
 explAin extended
 select * from t1 left join t2 on (t2.A= t1.A And t2.A in (select pk from t10));
 id	select_type	tABle	type	possiBle_keys	key	key_len	ref	rows	filtered	ExtrA
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join Buffer (flAt, BNL join)
-2	DEPENDENT SUBQUERY	t10	unique_suBquery	PRIMARY	PRIMARY	4	func	1	100.00	Using index
+2	SUBQUERY	t10	index	PRIMARY	PRIMARY	4	NULL	10	100.00	Using index
 Warnings:
-Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`t2`.`A` AS `A`,`test`.`t2`.`B` AS `B` from `test`.`t1` left join `test`.`t2` on((<in_optimizer>(`test`.`t2`.`A`,<exists>(<primAry_index_lookup>(<cAche>(`test`.`t2`.`A`) in t10 on PRIMARY))) And (`test`.`t2`.`A` = `test`.`t1`.`A`))) where 1
+Note	1003	select `test`.`t1`.`A` AS `A`,`test`.`t1`.`B` AS `B`,`test`.`t2`.`A` AS `A`,`test`.`t2`.`B` AS `B` from `test`.`t1` left join `test`.`t2` on((<in_optimizer>(`test`.`t2`.`A`,`test`.`t2`.`A` in ( <mAteriAlize> (select `test`.`t10`.`pk` from `test`.`t10` ), <primAry_index_lookup>(`test`.`t2`.`A` in <temporAry tABle> on distinct_key where ((`test`.`t2`.`A` = `<suBquery2>`.`pk`))))) And (`test`.`t2`.`A` = `test`.`t1`.`A`))) where 1
 we shouldn't flatten if we're going to get a join of > MAX_TABLES.
 explain select * from 
 t1 s00, t1 s01,  t1 s02, t1 s03, t1 s04,t1 s05,t1 s06,t1 s07,t1 s08,t1 s09,
@@ -735,9 +735,10 @@ SELECT int_key FROM ot1
 WHERE int_nokey IN (SELECT it2.int_key
 FROM it1 LEFT JOIN it2 ON it2.datetime_key);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	it1	index	NULL	int_key	4	NULL	2	Using index; Start temporary
-1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	20	Using join buffer (flat, BNL join)
-1	PRIMARY	it2	ALL	int_key,datetime_key	NULL	NULL	NULL	20	Using where; End temporary; Using join buffer (incremental, BNL join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	11	
+1	PRIMARY	ot1	ALL	NULL	NULL	NULL	NULL	20	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	it1	index	NULL	int_key	4	NULL	2	Using index
+2	SUBQUERY	it2	ALL	int_key,datetime_key	NULL	NULL	NULL	20	Using where; Using join buffer (flat, BNL join)
 DROP TABLE ot1, it1, it2;
 # End of BUG#38075
 #
@@ -809,9 +810,10 @@ INSERT INTO t2 VALUES (1,'i','iiii','iiii','iiii','iiii','ffff','ffff','ffff','f
 EXPLAIN EXTENDED SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-1	PRIMARY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Using where; Rowid-ordered scan; FirstMatch(t1); Using join buffer (flat, BNL join)
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	13	func,func	1	100.00	
+2	SUBQUERY	t2	range	PRIMARY	PRIMARY	4	NULL	2	100.00	Using index condition; Rowid-ordered scan
 Warnings:
-Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`b` = `test`.`t1`.`b`) and (`test`.`t2`.`a` = `test`.`t1`.`a`) and (`test`.`t2`.`pk` > 0))
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t2`.`pk` > 0))
 SELECT pk FROM t1 WHERE (a, b) IN (SELECT a, b FROM t2 WHERE pk > 0);
 pk
 2
@@ -977,9 +979,10 @@ FROM t1
 WHERE `varchar_nokey`  < 'n' XOR `pk`  )   ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	18	100.00	
-1	PRIMARY	t1	ref	varchar_key	varchar_key	3	test.t2.varchar_nokey	2	100.00	Using where; FirstMatch(t2); Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	8	func,func	1	100.00	
+2	SUBQUERY	t1	ALL	varchar_key	NULL	NULL	NULL	15	100.00	Using where
 Warnings:
-Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_key` = `test`.`t2`.`varchar_nokey`) and (`test`.`t1`.`varchar_nokey` = `test`.`t2`.`varchar_nokey`) and ((`test`.`t2`.`varchar_nokey` < 'n') xor `test`.`t1`.`pk`))
+Note	1003	select `test`.`t2`.`varchar_nokey` AS `varchar_nokey` from `test`.`t2` semi join (`test`.`t1`) where ((`test`.`t1`.`varchar_nokey` = `test`.`t1`.`varchar_key`) and ((`test`.`t1`.`varchar_key` < 'n') xor `test`.`t1`.`pk`))
 SELECT varchar_nokey
 FROM t2  
 WHERE ( `varchar_nokey`  , `varchar_nokey`  )  IN (  
@@ -1057,9 +1060,11 @@ WHERE  t2.val LIKE 'a%' OR t2.val LIKE 'e%')
 AND t1.val IN (SELECT t3.val FROM t3
 WHERE  t3.val LIKE 'a%' OR t3.val LIKE 'e%');
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	Start temporary
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; End temporary; Using join buffer (incremental, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	5	
+1	PRIMARY	<subquery3>	eq_ref	distinct_key	distinct_key	14	func	1	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	14	func	1	
+3	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	5	Using where
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	6	Using where
 SELECT *
 FROM t1
 WHERE t1.val IN (SELECT t2.val FROM t2
@@ -1277,10 +1282,12 @@ explain
 select * from t1 A, t1 B
 where A.a = B.a and A.a in (select a from t2 C) and B.a in (select a from t2 D);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	Start temporary
+1	PRIMARY	A	ALL	NULL	NULL	NULL	NULL	3	
+1	PRIMARY	<subquery2>	eq_ref	distinct_key	distinct_key	5	func	1	
 1	PRIMARY	B	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	C	ALL	NULL	NULL	NULL	NULL	3	Using where; Using join buffer (incremental, BNL join)
-1	PRIMARY	D	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (incremental, BNL join)
+1	PRIMARY	<subquery3>	eq_ref	distinct_key	distinct_key	5	func	1	
+2	SUBQUERY	C	ALL	NULL	NULL	NULL	NULL	3	
+3	SUBQUERY	D	ALL	NULL	NULL	NULL	NULL	3	
 drop table t1, t2;
 # 
 # BUG#784441: Abort on semijoin with a view as the inner table
@@ -1295,7 +1302,7 @@ SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
-2	DEPENDENT SUBQUERY	<derived3>	system	NULL	NULL	NULL	NULL	1	
+2	SUBQUERY	<derived3>	system	NULL	NULL	NULL	NULL	1	
 3	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 SELECT * FROM t1 INNER JOIN t2 ON t2.a != 0 AND t2.a IN (SELECT * FROM v1);
 a	a
@@ -1388,9 +1395,10 @@ insert into t3 values('three'),( 'four');
 insert into t3 values('three'),( 'four');
 explain select * from t3 where t3.b in (select t2.b from t1 left join t2 on t1.a=t2.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Start temporary
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	8	Using where; End temporary; Using join buffer (incremental, BNL join)
+1	PRIMARY	<subquery2>	ALL	distinct_key	NULL	NULL	NULL	2	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	8	Using where; Using join buffer (flat, BNL join)
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	
+2	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using join buffer (flat, BNL join)
 select * from t3 where t3.b in (select t2.b from t1 left join t2 on t1.a=t2.a);
 b
 drop table t1, t2, t3;

mysql-test/t/derived_view.test

@@ -394,7 +394,7 @@ DROP TABLE t1;
 --echo # LP bug #803851: materialized view + IN->EXISTS                       
 --echo #                 
 
-SET SESSION optimizer_switch='semijoin=off,derived_with_keys=on';
+SET SESSION optimizer_switch='semijoin=off,derived_with_keys=on,materialization=off';
 
 CREATE TABLE t1 (a int, b int);
 INSERT INTO t1 VALUES (2,2), (3,3), (1,1);
@@ -895,7 +895,7 @@ INSERT INTO t3 VALUES
   (14,4,'a'), (15,7,'b'), (16,4,'c'), (17,1,'d'), (18,9,'e'),
   (19,4,'f'), (20,8,'g');
 
-SET SESSION optimizer_switch='derived_merge=on,subquery_cache=off';
+SET SESSION optimizer_switch='derived_merge=on,subquery_cache=off,materialization=off';
 
 --echo # The following two EXPLAINs must return the same execution plan
 EXPLAIN

mysql-test/t/subselect3.test

@@ -872,12 +872,17 @@ create table t12 select * from t1 where b = 67 AND (c IS NULL OR c > NOW()) orde
 create table t21 select * from t1 where b = 67 AND (c IS NULL OR c > '2005-12-08') order by 3 asc;
 create table t22 select * from t1 where b = 67 AND (c IS NULL OR c > '2005-12-08') order by 3 desc;
 
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
+
 update t22 set c = '2005-12-08 15:58:27' where a = 255;
 explain select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 select t21.* from t21,t22 where t21.a = t22.a and 
 t22.a in (select t12.a from t11, t12 where t11.a in(255,256) and t11.a = t12.a and t11.c is null) and t22.c is null order by t21.a;
 
+set @@optimizer_switch=@save_optimizer_switch;
+
 drop table t1, t11, t12, t21, t22;
 
 #
@@ -888,7 +893,7 @@ drop table t1, t11, t12, t21, t22;
 create table t1(a int);
 insert into t1 values (0),(1);
 
-set @@optimizer_switch='firstmatch=off';
+set @@optimizer_switch='firstmatch=off,materialization=off';
 explain 
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
 select (select max(Y.a) from t1 Y where a in (select a from t1 Z) and a < X.a) as subq from t1 X;
@@ -914,6 +919,9 @@ select * from t1 where 2 in (select a from t0);
 set @@optimizer_switch=@save_optimizer_switch;
 
 
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
+
 # 
 # FirstMatch referring to a derived table
 #
@@ -943,6 +951,8 @@ and t4.pk=t1.c);
 
 drop table t1, t3, t4;
 
+set @@optimizer_switch=@save_optimizer_switch;
+
 #
 # Test if we handle duplicate elimination temptable overflowing to disk
 #
@@ -997,6 +1007,9 @@ explain select * from t1 where a in (select a from t1);
 drop table t1;
 set @@optimizer_switch=@save_optimizer_switch;
 
+set @@optimizer_switch=@save_optimizer_switch;
+set @@optimizer_switch='materialization=off';
+
 #
 # SJ-Materialization-scan for non-first table
 #
@@ -1040,6 +1053,8 @@ explain select * from t2 where (b,a) in (select a,b from t1 where a=3);
 
 drop table t1,t2;
 
+set @@optimizer_switch=@save_optimizer_switch;
+
 #
 # Multi-column sj-materialization with lookups
 #
@@ -1048,7 +1063,7 @@ insert into t1 select a,a from t0;
 create table t2 (a int, b int); 
 insert into t2 select A.a + 10*B.a, A.a + 10*B.a from t0 A, t0 B;
 
-set @@optimizer_switch='firstmatch=off';
+set @@optimizer_switch='firstmatch=off,materialization=off';
 explain select * from t1 where (a,b) in (select a,b from t2);
 
 # A smallish test if find_best() still works for semi-join optimization:
@@ -1060,6 +1075,7 @@ set @@optimizer_switch=@save_optimizer_switch;
 
 drop table t0, t1, t2;
 
+set @@optimizer_switch='materialization=off';
 
 #
 # Primitive SJ-Materialization tests for DECIMAL and DATE
@@ -1094,6 +1110,8 @@ explain select * from t1 where (a,b,c) in (select X.a, Y.a, Z.a from t2 X, t2 Y,
 
 drop table t0,t1,t2;
 
+set @@optimizer_switch=@save_optimizer_switch;
+
 --echo
 --echo BUG#37842: Assertion in DsMrr_impl::dsmrr_init, at handler.cc:4307
 --echo
@@ -1150,12 +1168,15 @@ create table t3 (
 insert into t3 values (1,1, 'foo'), (2,2,'bar');
 
 --echo The following must be converted to a semi-join:
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch='materialization=off';
 explain extended SELECT a.idIndividual FROM t1 a 
 WHERE a.idIndividual IN 
 	(	SELECT c.idObj FROM t3 cona 
 		INNER JOIN t2 c ON c.idContact=cona.idContact 
 		WHERE cona.postalStripped='T2H3B2'
 	);
+set @@optimizer_switch=@save_optimizer_switch;
 drop table t1,t2,t3;
 
 --echo #

mysql-test/t/subselect4.test

@@ -124,6 +124,9 @@ INSERT INTO t4 VALUES (1), (2), (3);
 CREATE TABLE t5 ( a INT );
 INSERT INTO t5 VALUES (NULL), (2);
 
+SET @old_optimizer_switch = @@session.optimizer_switch;
+SET SESSION optimizer_switch = 'materialization=off,in_to_exists=on,semijoin=off';
+
 --replace_column 1 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 x
 EXPLAIN
 SELECT * FROM t1 WHERE ( a, b ) NOT IN ( SELECT c, d FROM t2 );
@@ -165,6 +168,8 @@ SELECT * FROM t1 WHERE b NOT IN ( SELECT c FROM t2 WHERE c = 1 );
 
 SELECT * FROM t1 WHERE NULL NOT IN ( SELECT c FROM t2 WHERE c = 1 AND c <> 1 );
 
+SET SESSION optimizer_switch = @old_optimizer_switch;
+
 DROP TABLE t1, t2, t3, t4, t5;
 
 --echo #

mysql-test/t/subselect_mat_cost_bugs.test

@@ -323,7 +323,7 @@ create index key1 on t2 (kp1, kp2);
 create index key2 on t2 (kp1);
 create index key3 on t2 (kp2);
 
-set session optimizer_switch='default';
+SET @@optimizer_switch='materialization=off,semijoin=off,in_to_exists=on';
 
 analyze table t2;
 
@@ -331,6 +331,8 @@ explain
 select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
 select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
 
+set @@optimizer_switch='default';
+
 drop table t1, t2;
 
 --echo #

sql/item_subselect.cc

@@ -159,8 +159,6 @@ void Item_in_subselect::cleanup()
     left_expr_cache= NULL;
   }
   first_execution= TRUE;
-  if (in_strategy & SUBS_MATERIALIZATION)
-    in_strategy= 0;
   pushed_cond_guards= NULL;
   Item_subselect::cleanup();
   DBUG_VOID_RETURN;

sql/mysql_priv.h

@@ -593,17 +593,13 @@ protected:
 #define OPTIMIZER_SWITCH_LAST                      (1ULL << 26)
 
 /* The following must be kept in sync with optimizer_switch_str in mysqld.cc */
-/*
-TODO: Materialization is off by default to mimic 5.1/5.2 behavior.
-Once cost based choice between materialization and in-to-exists should be
-enabled by default, add OPTIMIZER_SWITCH_MATERIALIZATION
-*/
 #define OPTIMIZER_SWITCH_DEFAULT   (OPTIMIZER_SWITCH_INDEX_MERGE | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_UNION | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_INTERSECT | \
                                     OPTIMIZER_SWITCH_TABLE_ELIMINATION | \
                                     OPTIMIZER_SWITCH_IN_TO_EXISTS | \
+                                    OPTIMIZER_SWITCH_MATERIALIZATION | \
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE|\
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN|\
                                     OPTIMIZER_SWITCH_JOIN_CACHE_INCREMENTAL | \

sql/mysqld.cc

@@ -486,7 +486,7 @@ static const char *optimizer_switch_str="index_merge=on,index_merge_union=on,"
                                         "derived_with_keys=off,"
                                         "firstmatch=on,"
                                         "loosescan=on,"
-                                        "materialization=off,"
+                                        "materialization=on,"
                                         "in_to_exists=on,"
                                         "semijoin=on,"
                                         "partial_match_rowid_merge=on,"