Change the default @@optimizer_switch settings:

- semijoin=on
- firstmatch=on
- loosescan=on

mysql-test/r/derived_view.result

@@ -989,10 +989,10 @@ SELECT * FROM t2 RIGHT JOIN (SELECT * FROM t1) AS t ON t.a != 0
 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	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	
 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` semi join (`test`.`t1`) left join `test`.`t2` on((0 <> 0)) where 1
 SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
 WHERE t.a IN (SELECT b FROM t1);
 a	a	b
@@ -1002,10 +1002,10 @@ SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
 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	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	
 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` semi join (`test`.`t1`) left join `test`.`t2` on((0 <> 0)) where 1
 DROP VIEW v1;
 DROP TABLE t1,t2;
 #
@@ -1147,7 +1147,7 @@ EXPLAIN
 SELECT a FROM t1 WHERE (a,b) 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	Using where
-2	DEPENDENT SUBQUERY	<derived3>	index_subquery	key0	key0	10	func,func	2	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	10	test.t1.a,test.t1.b	2	FirstMatch(t1)
 3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	6	Using temporary; Using filesort
 SELECT * FROM v2;
 a	b
@@ -1167,7 +1167,7 @@ EXPLAIN
 SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	<derived3>	index_subquery	key0	key0	10	func,func	2	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	10	test.t1.a,test.t1.b	2	FirstMatch(t1)
 3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	6	
 4	UNION	t3	ALL	NULL	NULL	NULL	NULL	4	
 NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
@@ -1478,9 +1478,9 @@ SELECT * FROM t3
 WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
 WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	t2	system	NULL	NULL	NULL	NULL	1	
-2	DEPENDENT SUBQUERY	<derived3>	ALL	NULL	NULL	NULL	NULL	3	Using where
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (flat, BNL join)
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	3	
 SELECT * FROM t3 
 WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
@@ -1493,9 +1493,9 @@ SELECT * FROM t3
 WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
 WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	t2	system	NULL	NULL	NULL	NULL	1	
-2	DEPENDENT SUBQUERY	<derived3>	ref	key1	key1	10	const,const	0	Using where
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	<derived3>	ref	key1	key1	10	const,const	0	Start temporary
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	3	
 SELECT * FROM t3 
 WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
@@ -1517,7 +1517,7 @@ EXPLAIN
 SELECT * FROM t1 WHERE t1.b IN (SELECT v2.a FROM v2 WHERE v2.b = t1.a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	<derived3>	ref	key0	key0	5	test.t1.a	2	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	10	test.t1.b,test.t1.a	2	FirstMatch(t1)
 3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	
 SELECT * FROM t1 WHERE t1.b IN (SELECT v2.a FROM v2 WHERE v2.b = t1.a);
 a	b

mysql-test/r/explain.result

@@ -199,16 +199,16 @@ insert into t2 values ('2001-01-01 1:1:1'), ('2001-01-01 1:1:1');
 flush tables;
 EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	OUTR	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	INNR	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	OUTR	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	INNR	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
 flush tables;
 SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN (SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.dt IS NULL );
 dt
 flush tables;
 EXPLAIN SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	OUTR	ALL	NULL	NULL	NULL	NULL	2	Using where
-2	DEPENDENT SUBQUERY	INNR	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	OUTR	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	INNR	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
 flush tables;
 SELECT OUTR.dt FROM t1 AS OUTR WHERE OUTR.dt IN ( SELECT INNR.dt FROM t2 AS INNR WHERE OUTR.t < '2005-11-13 7:41:31' );
 dt

mysql-test/r/group_by.result

@@ -1542,8 +1542,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 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
+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)
 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;
@@ -1555,8 +1555,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 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
+1	PRIMARY	t2	index	a	a	5	NULL	4	Using index
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where; FirstMatch(t2)
 SHOW VARIABLES LIKE 'old';
 Variable_name	Value
 old	OFF

mysql-test/r/group_min_max.result

@@ -1432,7 +1432,7 @@ group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	range	NULL	idx_t1_1	147	NULL	17	Using where; Using index for group-by
 2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
-3	DEPENDENT SUBQUERY	t3	index	NULL	idx_t3_1	10	NULL	192	Using where; Using index
+2	DEPENDENT SUBQUERY	t3	index	NULL	idx_t3_1	10	NULL	192	Using where; Using index; FirstMatch(t2)
 select a1,a2,b,c,min(c), max(c) from t1
 where exists ( select * from t2
 where t2.c in (select c from t3 where t3.c > t1.b) and
@@ -1489,7 +1489,7 @@ group by a1,a2,b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	index	NULL	idx_t1_1	163	NULL	128	Using where; Using index
 2	DEPENDENT SUBQUERY	t2	index	NULL	idx_t2_1	163	NULL	164	Using where; Using index
-3	DEPENDENT SUBQUERY	t3	index	NULL	idx_t3_1	10	NULL	192	Using where; Using index
+2	DEPENDENT SUBQUERY	t3	index	NULL	idx_t3_1	10	NULL	192	Using where; Using index; FirstMatch(t2)
 select a1,a2,b,c,min(c), max(c) from t1
 where exists ( select * from t2
 where t2.c in (select c from t3 where t3.c > t1.c) and

mysql-test/r/subselect4.result

@@ -2113,7 +2113,7 @@ CREATE TABLE t3 (a int, b int) ;
 INSERT INTO t3 VALUES (5,0),(7,0);
 CREATE TABLE t4 (a int);
 INSERT INTO t4 VALUES (2),(8);
-set @@optimizer_switch='in_to_exists=on,materialization=off,subquery_cache=off';
+set @@optimizer_switch='semijoin=off,in_to_exists=on,materialization=off,subquery_cache=off';
 SELECT * FROM t2
 WHERE t2.b IN (SELECT b FROM t3 WHERE t3.a = t2.a AND a < SOME (SELECT * FROM t4))
 OR ( t2.c > 242 );

mysql-test/r/subselect_extra.result

 drop table if exists t1,t2,t3,t4;
-set @subselect_extra_tmp=@@optimizer_switch;
-set optimizer_switch='semijoin=on,firstmatch=on,loosescan=on';
+drop view if exists v1,v2,v3;
 # From explain.test:
 #
 # Bug#37870: Usage of uninitialized value caused failed assertion.
@@ -320,4 +319,157 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t2	index	a	a	5	NULL	4	Using index
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	144	Using where; FirstMatch(t2)
 DROP TABLE t1, t2;
-set optimizer_switch= @subselect_extra_tmp;
+# 
+# From derived_view.test
+#
+set @tmp_subselect_extra_derived=@@optimizer_switch;
+set optimizer_switch='derived_merge=on,derived_with_keys=on';
+#
+# LP bug #806504: right join over a view/derived table           
+#
+CREATE TABLE t1 (a int, b int) ;
+INSERT INTO t1 VALUES (0,0);
+CREATE TABLE t2 (a int) ;
+INSERT INTO t2 VALUES (0), (0);
+CREATE VIEW v1 AS SELECT * FROM t1;
+SELECT * FROM t2 RIGHT JOIN (SELECT * FROM t1) AS t ON t.a != 0
+WHERE t.a IN (SELECT b FROM t1);
+a	a	b
+NULL	0	0
+EXPLAIN EXTENDED
+SELECT * FROM t2 RIGHT JOIN (SELECT * FROM t1) AS t ON t.a != 0
+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	t1	system	NULL	NULL	NULL	NULL	1	100.00	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` semi join (`test`.`t1`) left join `test`.`t2` on((0 <> 0)) where 1
+SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
+WHERE t.a IN (SELECT b FROM t1);
+a	a	b
+NULL	0	0
+EXPLAIN EXTENDED
+SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
+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	t1	system	NULL	NULL	NULL	NULL	1	100.00	
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+Warnings:
+Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` semi join (`test`.`t1`) left join `test`.`t2` on((0 <> 0)) where 1
+DROP VIEW v1;
+DROP TABLE t1,t2;
+#
+# LP bug #793448: materialized view accessed by two-component key           
+#
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (9,3), (2,5);
+CREATE TABLE t2 (a int, b int);
+INSERT INTO t2 VALUES (9,3), (3,7), (9,1), (2,5), (2,4), (3,8);
+CREATE TABLE t3 (a int, b int);
+INSERT INTO t3 VALUES (10,3), (9,7), (9,1), (2,4);
+CREATE VIEW v1(a,b) AS SELECT a, MAX(b) FROM t2 GROUP BY a;
+CREATE VIEW v2(a,b) AS SELECT a,b FROM t2 UNION SELECT a,b FROM t3;
+SELECT * FROM v1;
+a	b
+2	5
+3	8
+9	3
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v1);
+a
+9
+2
+EXPLAIN 
+SELECT a FROM t1 WHERE (a,b) 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	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	10	test.t1.a,test.t1.b	2	FirstMatch(t1)
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	6	Using temporary; Using filesort
+SELECT * FROM v2;
+a	b
+9	3
+3	7
+9	1
+2	5
+2	4
+3	8
+10	3
+9	7
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v2);
+a
+9
+2
+EXPLAIN 
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v2);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	10	test.t1.a,test.t1.b	2	FirstMatch(t1)
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	6	
+4	UNION	t3	ALL	NULL	NULL	NULL	NULL	4	
+NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
+DROP VIEW v1,v2;
+DROP TABLE t1,t2,t3;
+#
+# LP bug #874006: materialized view used in IN subquery
+#
+CREATE TABLE t3 (a int NOT NULL, b varchar(1), c varchar(1));
+INSERT INTO t3 VALUES (19,NULL,NULL), (20,'r','r');
+CREATE TABLE t1 (a int, b varchar(1) , c varchar(1));
+INSERT INTO t1 VALUES (1,NULL,NULL), (5,'r','r'), (7,'y','y');
+CREATE TABLE t2 (a int NOT NULL , b int, c varchar(1));
+INSERT INTO t2 VALUES (4,3,'r');
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+SET SESSION optimizer_switch='derived_with_keys=off';
+EXPLAIN
+SELECT * FROM t3 
+WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; Start temporary
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	3	Using where; End temporary; Using join buffer (flat, BNL join)
+3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	3	
+SELECT * FROM t3 
+WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+a	b	c
+20	r	r
+SET SESSION optimizer_switch='derived_with_keys=on';
+EXPLAIN
+SELECT * FROM t3 
+WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	<derived3>	ref	key1	key1	10	const,const	0	Start temporary
+1	PRIMARY	t3	ALL	NULL	NULL	NULL	NULL	2	Using where; End temporary; Using join buffer (flat, BNL join)
+3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	3	
+SELECT * FROM t3 
+WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+a	b	c
+20	r	r
+DROP VIEW v1;
+DROP TABLE t1,t2,t3;
+#
+# LP bug #873263: materialized view used in correlated IN subquery
+#
+CREATE TABLE t1 (a int, b int) ;
+INSERT INTO t1 VALUES (5,4), (9,8);
+CREATE TABLE t2 (a int, b int) ;
+INSERT INTO t2 VALUES (4,5), (5,1);
+CREATE ALGORITHM=TEMPTABLE VIEW v2 AS SELECT * FROM t2;
+SET SESSION optimizer_switch='derived_with_keys=on';
+EXPLAIN
+SELECT * FROM t1 WHERE t1.b IN (SELECT v2.a FROM v2 WHERE v2.b = t1.a);
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	PRIMARY	<derived3>	ref	key0	key0	10	test.t1.b,test.t1.a	2	FirstMatch(t1)
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	
+SELECT * FROM t1 WHERE t1.b IN (SELECT v2.a FROM v2 WHERE v2.b = t1.a);
+a	b
+5	4
+DROP VIEW v2;
+DROP TABLE t1,t2;
+set optimizer_switch= @tmp_subselect_extra_derived;

mysql-test/r/subselect_nulls.result

 drop table if exists x1;
 drop table if exists x2;
+set @tmp_subselect_nulls=@@optimizer_switch;
+set optimizer_switch='semijoin=off';
 create table x1(k int primary key, d1 int, d2 int);
 create table x2(k int primary key, d1 int, d2 int);
 insert into x1 values
@@ -110,5 +112,6 @@ where x1.d1=x2.d1 and x1.d2=x2.d2);
 k	d1	d2
 10	10	10
 20	20	20
+set optimizer_switch= @tmp_subselect_nulls;
 drop table x1;
 drop table x2;

mysql-test/r/type_datetime.result

@@ -514,11 +514,10 @@ explain extended
 select * from t1
 where id in (select id from t1 as x1 where (t1.cur_date is null));
 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	
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1276	Field or reference 'test.t1.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select 1 AS `id`,'2007-04-25 18:30:22' AS `cur_date` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select `test`.`x1`.`id` from `test`.`t1` `x1` where 0)))
+Note	1003	select 1 AS `id`,'2007-04-25 18:30:22' AS `cur_date` from `test`.`t1` semi join (`test`.`t1` `x1`) where (('2007-04-25 18:30:22' = 0))
 select * from t1
 where id in (select id from t1 as x1 where (t1.cur_date is null));
 id	cur_date
@@ -526,11 +525,10 @@ explain extended
 select * from t2
 where id in (select id from t2 as x1 where (t2.cur_date is null));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	system	NULL	NULL	NULL	NULL	1	100.00	
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1276	Field or reference 'test.t2.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select 1 AS `id`,'2007-04-25' AS `cur_date` from `test`.`t2` where <expr_cache><1>(<in_optimizer>(1,<exists>(select `test`.`x1`.`id` from `test`.`t2` `x1` where 0)))
+Note	1003	select 1 AS `id`,'2007-04-25' AS `cur_date` from `test`.`t2` semi join (`test`.`t2` `x1`) where (('2007-04-25' = 0))
 select * from t2
 where id in (select id from t2 as x1 where (t2.cur_date is null));
 id	cur_date
@@ -540,11 +538,11 @@ explain extended
 select * from t1
 where id in (select id from t1 as x1 where (t1.cur_date is null));
 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	Using where
-2	DEPENDENT SUBQUERY	x1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Start temporary
+1	PRIMARY	x1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; End temporary; Using join buffer (flat, BNL join)
 Warnings:
 Note	1276	Field or reference 'test.t1.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`id` AS `id`,`test`.`t1`.`cur_date` AS `cur_date` from `test`.`t1` where <expr_cache><`test`.`t1`.`id`,`test`.`t1`.`cur_date`>(<in_optimizer>(`test`.`t1`.`id`,<exists>(select `test`.`x1`.`id` from `test`.`t1` `x1` where ((`test`.`t1`.`cur_date` = 0) and (<cache>(`test`.`t1`.`id`) = `test`.`x1`.`id`)))))
+Note	1003	select `test`.`t1`.`id` AS `id`,`test`.`t1`.`cur_date` AS `cur_date` from `test`.`t1` semi join (`test`.`t1` `x1`) where ((`test`.`x1`.`id` = `test`.`t1`.`id`) and (`test`.`t1`.`cur_date` = 0))
 select * from t1
 where id in (select id from t1 as x1 where (t1.cur_date is null));
 id	cur_date
@@ -552,11 +550,11 @@ explain extended
 select * from t2
 where id in (select id from t2 as x1 where (t2.cur_date is null));
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
-2	DEPENDENT SUBQUERY	x1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Start temporary
+1	PRIMARY	x1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; End temporary; Using join buffer (flat, BNL join)
 Warnings:
 Note	1276	Field or reference 'test.t2.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`id` AS `id`,`test`.`t2`.`cur_date` AS `cur_date` from `test`.`t2` where <expr_cache><`test`.`t2`.`id`,`test`.`t2`.`cur_date`>(<in_optimizer>(`test`.`t2`.`id`,<exists>(select `test`.`x1`.`id` from `test`.`t2` `x1` where ((`test`.`t2`.`cur_date` = 0) and (<cache>(`test`.`t2`.`id`) = `test`.`x1`.`id`)))))
+Note	1003	select `test`.`t2`.`id` AS `id`,`test`.`t2`.`cur_date` AS `cur_date` from `test`.`t2` semi join (`test`.`t2` `x1`) where ((`test`.`x1`.`id` = `test`.`t2`.`id`) and (`test`.`t2`.`cur_date` = 0))
 select * from t2
 where id in (select id from t2 as x1 where (t2.cur_date is null));
 id	cur_date

mysql-test/t/subselect4.test

@@ -1749,7 +1749,7 @@ INSERT INTO t3 VALUES (5,0),(7,0);
 CREATE TABLE t4 (a int);
 INSERT INTO t4 VALUES (2),(8);
 
-set @@optimizer_switch='in_to_exists=on,materialization=off,subquery_cache=off';
+set @@optimizer_switch='semijoin=off,in_to_exists=on,materialization=off,subquery_cache=off';
 
 SELECT * FROM t2
 WHERE t2.b IN (SELECT b FROM t3 WHERE t3.a = t2.a AND a < SOME (SELECT * FROM t4))

mysql-test/t/subselect_extra.test

@@ -9,11 +9,9 @@
 
 --disable_warnings
 drop table if exists t1,t2,t3,t4;
+drop view if exists v1,v2,v3;
 --enable_warnings
 
-set @subselect_extra_tmp=@@optimizer_switch;
-set optimizer_switch='semijoin=on,firstmatch=on,loosescan=on';
-
 
 --echo # From explain.test:
 --echo #
@@ -273,6 +271,123 @@ EXPLAIN SELECT 1 FROM t2 WHERE a IN
   (SELECT a FROM t1 USE INDEX (i2) IGNORE INDEX (i2));
 DROP TABLE t1, t2;
 
+--echo # 
+--echo # From derived_view.test
+--echo #
+set @tmp_subselect_extra_derived=@@optimizer_switch;
+set optimizer_switch='derived_merge=on,derived_with_keys=on';
+
+--echo #
+--echo # LP bug #806504: right join over a view/derived table           
+--echo #
+
+CREATE TABLE t1 (a int, b int) ;
+INSERT INTO t1 VALUES (0,0);
+
+CREATE TABLE t2 (a int) ;
+INSERT INTO t2 VALUES (0), (0);
+
+CREATE VIEW v1 AS SELECT * FROM t1;
+
+SELECT * FROM t2 RIGHT JOIN (SELECT * FROM t1) AS t ON t.a != 0
+  WHERE t.a IN (SELECT b FROM t1);
+EXPLAIN EXTENDED
+SELECT * FROM t2 RIGHT JOIN (SELECT * FROM t1) AS t ON t.a != 0
+  WHERE t.a IN (SELECT b FROM t1);
+
+SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
+  WHERE t.a IN (SELECT b FROM t1);
+EXPLAIN EXTENDED
+SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
+  WHERE t.a IN (SELECT b FROM t1);
+
+DROP VIEW v1;
+DROP TABLE t1,t2;
+
+--echo #
+--echo # LP bug #793448: materialized view accessed by two-component key           
+--echo #
+
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (9,3), (2,5);
+
+CREATE TABLE t2 (a int, b int);
+INSERT INTO t2 VALUES (9,3), (3,7), (9,1), (2,5), (2,4), (3,8);
+
+CREATE TABLE t3 (a int, b int);
+INSERT INTO t3 VALUES (10,3), (9,7), (9,1), (2,4);
+
+CREATE VIEW v1(a,b) AS SELECT a, MAX(b) FROM t2 GROUP BY a;
+CREATE VIEW v2(a,b) AS SELECT a,b FROM t2 UNION SELECT a,b FROM t3;
+
+SELECT * FROM v1;
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v1);
+EXPLAIN 
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v1);
+
+SELECT * FROM v2;
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v2);
+EXPLAIN 
+SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v2);
+
+DROP VIEW v1,v2;
+DROP TABLE t1,t2,t3;
+
+--echo #
+--echo # LP bug #874006: materialized view used in IN subquery
+--echo #
+
+CREATE TABLE t3 (a int NOT NULL, b varchar(1), c varchar(1));
+INSERT INTO t3 VALUES (19,NULL,NULL), (20,'r','r');
+
+CREATE TABLE t1 (a int, b varchar(1) , c varchar(1));
+INSERT INTO t1 VALUES (1,NULL,NULL), (5,'r','r'), (7,'y','y');
+
+CREATE TABLE t2 (a int NOT NULL , b int, c varchar(1));
+INSERT INTO t2 VALUES (4,3,'r');
+
+CREATE ALGORITHM=TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+
+SET SESSION optimizer_switch='derived_with_keys=off';
+EXPLAIN
+SELECT * FROM t3 
+  WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+                   WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+SELECT * FROM t3 
+  WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+                   WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+
+SET SESSION optimizer_switch='derived_with_keys=on';
+EXPLAIN
+SELECT * FROM t3 
+  WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+                   WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+SELECT * FROM t3 
+  WHERE t3.b IN (SELECT v1.b FROM  v1, t2 
+                   WHERE t2.c = v1.c AND t2.c = v1.b AND v1.b = t3.c);
+
+DROP VIEW v1;
+DROP TABLE t1,t2,t3;
+
+--echo #
+--echo # LP bug #873263: materialized view used in correlated IN subquery
+--echo #
+
+CREATE TABLE t1 (a int, b int) ;
+INSERT INTO t1 VALUES (5,4), (9,8);
+
+CREATE TABLE t2 (a int, b int) ;
+INSERT INTO t2 VALUES (4,5), (5,1);
+
+CREATE ALGORITHM=TEMPTABLE VIEW v2 AS SELECT * FROM t2;
+
+SET SESSION optimizer_switch='derived_with_keys=on';
+EXPLAIN
+SELECT * FROM t1 WHERE t1.b IN (SELECT v2.a FROM v2 WHERE v2.b = t1.a);
+SELECT * FROM t1 WHERE t1.b IN (SELECT v2.a FROM v2 WHERE v2.b = t1.a);
+
+DROP VIEW v2;
+DROP TABLE t1,t2;
 
-set optimizer_switch= @subselect_extra_tmp;
+set optimizer_switch= @tmp_subselect_extra_derived;
 

mysql-test/t/subselect_extra_no_semijoin.test

+set @subselect_extra_no_sj_tmp=@@optimizer_switch;
+set optimizer_switch='semijoin=on,firstmatch=on,loosescan=on';
+
+--source t/subselect_extra.test
+
+set optimizer_switch= @subselect_extra_no_sj_tmp;
+

mysql-test/t/subselect_innodb.test

 -- source include/have_innodb.inc
 
+# Note: the tests uses only non-semijoin subqueries so semi-join switch
+#       settings are not relevant.
 set @subselect_innodb_tmp=@@optimizer_switch;
 set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
 --disable_warnings

mysql-test/t/subselect_nulls.test

@@ -5,6 +5,9 @@ drop table if exists x1;
 drop table if exists x2;
 --enable_warnings
 
+set @tmp_subselect_nulls=@@optimizer_switch;
+set optimizer_switch='semijoin=off';
+
 create table x1(k int primary key, d1 int, d2 int);
 create table x2(k int primary key, d1 int, d2 int);
 
@@ -90,5 +93,7 @@ where exists (select *
               from x2
               where x1.d1=x2.d1 and x1.d2=x2.d2);
 
+set optimizer_switch= @tmp_subselect_nulls;
+
 drop table x1;
 drop table x2;

sql/mysql_priv.h

@@ -609,7 +609,10 @@ enabled by default, add OPTIMIZER_SWITCH_MATERIALIZATION
                                     OPTIMIZER_SWITCH_JOIN_CACHE_INCREMENTAL | \
                                     OPTIMIZER_SWITCH_JOIN_CACHE_HASHED | \
                                     OPTIMIZER_SWITCH_JOIN_CACHE_BKA | \
-                                    OPTIMIZER_SWITCH_SUBQUERY_CACHE)
+                                    OPTIMIZER_SWITCH_SUBQUERY_CACHE |\
+                                    OPTIMIZER_SWITCH_SEMIJOIN | \
+                                    OPTIMIZER_SWITCH_FIRSTMATCH | \
+                                    OPTIMIZER_SWITCH_LOOSE_SCAN )
 
 /*
   Replication uses 8 bytes to store SQL_MODE in the binary log. The day you

sql/mysqld.cc

@@ -484,11 +484,11 @@ static const char *optimizer_switch_str="index_merge=on,index_merge_union=on,"
                                         "index_condition_pushdown=off,"
                                         "derived_merge=off,"
                                         "derived_with_keys=off,"
-                                        "firstmatch=off,"
-                                        "loosescan=off,"
+                                        "firstmatch=on,"
+                                        "loosescan=on,"
                                         "materialization=off,"
                                         "in_to_exists=on,"
-                                        "semijoin=off,"
+                                        "semijoin=on,"
                                         "partial_match_rowid_merge=on,"
                                         "partial_match_table_scan=on,"
                                         "subquery_cache=on,"