Made the optimizer switches 'derived_merge' and 'derived_with_keys'

off by default.

44 files changed, 670 insertions, 295 deletions

diff --git a/mysql-test/include/ps_query.inc b/mysql-test/include/ps_query.inc
index ae6027a0e07..eafe651a2e7 100644
--- a/mysql-test/include/ps_query.inc
+++ b/mysql-test/include/ps_query.inc
@@ -528,6 +528,8 @@ drop table t5, t6, t7 ;
 --disable_warnings
 drop table if exists t2 ;
 --enable_warnings
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 ## unusual and complex SELECT without parameters
 set @stmt= ' SELECT
@@ -596,7 +598,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
                     @arg07, @arg08, @arg09 ;
 --enable_result_log
 drop table t2 ;
-
+set optimizer_switch=@save_optimizer_switch; 
 
 ##### test case derived from client_test.c: test_bug4079()
 --error 1242
diff --git a/mysql-test/r/derived.result b/mysql-test/r/derived.result
index 5ea398a6c09..b1225c31575 100644
--- a/mysql-test/r/derived.result
+++ b/mysql-test/r/derived.result
@@ -57,8 +57,9 @@ a	b	a	b
 3	c	3	c
 explain select * from t1 as x1, (select * from t1) as x2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	x1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
+1	PRIMARY	x1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	4	
 drop table if exists  t2,t3;
 select * from (select 1) as a;
 1
@@ -112,8 +113,9 @@ a	b
 3	c
 explain select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	
+2	DERIVED	t2	system	NULL	NULL	NULL	NULL	1	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
 drop table t1, t2;
 create table t1(a int not null, t char(8), index(a));
 SELECT * FROM (SELECT * FROM t1) as b ORDER BY a  ASC LIMIT 0,20;
@@ -140,7 +142,9 @@ a	t
 20	20
 explain select count(*) from t1 as tt1, (select * from t1) as tt2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+1	PRIMARY	tt1	index	NULL	a	4	NULL	10000	Using index
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10000	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	10000	
 drop table t1;
 SELECT * FROM (SELECT (SELECT * FROM (SELECT 1 as a) as a )) as b;
 (SELECT * FROM (SELECT 1 as a) as a )
@@ -169,30 +173,30 @@ insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd'
 insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
 SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 pla_id	mat_id
-102	1
-101	1
 100	1
-104	2
+101	1
+102	1
 103	2
+104	2
 105	3
 SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 pla_id	test
-102	1
-101	1
 100	1
-104	2
+101	1
+102	1
 103	2
+104	2
 105	3
 explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
-1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
+1	PRIMARY	<derived2>	ALL	NULL	$hj	7	test.m2.matintnum	9	Using where
 2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
 2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
 explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
-1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
+1	PRIMARY	<derived2>	ALL	NULL	$hj	7	test.m2.matintnum	9	Using where
 2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
 2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
 drop table t1,t2;
@@ -227,8 +231,9 @@ count(*)
 2
 explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	2	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.A.E2	1	Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t1	eq_ref	PRIMARY	PRIMARY	4	THEMAX.E2	1	Using where
+2	DERIVED	A	ALL	NULL	NULL	NULL	NULL	2	Using where
 3	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	2	Using where
 drop table t1;
 create table t1 (a int);
@@ -318,7 +323,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
 explain select a from (select a from t2 where a>1) tt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+2	DERIVED	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
 drop table t2;
 CREATE TABLE `t1` ( `itemid` int(11) NOT NULL default '0', `grpid` varchar(15) NOT NULL default '', `vendor` int(11) NOT NULL default '0', `date_` date NOT NULL default '0000-00-00', `price` decimal(12,2) NOT NULL default '0.00', PRIMARY KEY  (`itemid`,`grpid`,`vendor`,`date_`), KEY `itemid` (`itemid`,`vendor`), KEY `itemid_2` (`itemid`,`date_`));
 insert into t1 values (128, 'rozn', 2, curdate(), 10),
@@ -407,73 +413,3 @@ MIN(i)
 1
 DROP TABLE t1;
 # End of 5.0 tests
-#
-#  LP bug #793436: query with a derived table for which optimizer proves
-#                  that it contains not more than 1 row
-#
-CREATE TABLE t1 (a int, KEY (a)) ;
-INSERT INTO t1 VALUES (3), (1);
-CREATE TABLE t2 (a int);
-INSERT INTO t2 VALUES (3);
-EXPLAIN
-SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
-1	PRIMARY	t1	ref	a	a	5	const	1	Using index
-2	DERIVED	t2	system	NULL	NULL	NULL	NULL	1	
-SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
-a	a
-3	3
-DROP TABLE t1,t2;
-#
-#  LP bug #800518: crash with a query over a derived table
-#                  when a min/max optimization is applied
-#
-CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
-INSERT INTO t1 VALUES 
-(100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
-(200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
-EXPLAIN
-SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
-SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
-MAX(b)
-5
-DROP TABLE t1;
-#
-#  LP bug #799499: query over a materialized view 
-#                  accessed by a key
-#
-CREATE TABLE t1 (a int) ;
-INSERT INTO t1 VALUES (8);
-CREATE TABLE t2 (a int, b int) ;
-INSERT INTO t2 VALUES
-(262, NULL), (253, 190), (260, NULL), (250, 163), (188, 8),
-(257,200), (256, NULL), (255, 8), (249, NULL), (259, 7);
-CREATE VIEW v1 AS SELECT a, MIN(b) AS b FROM t2 GROUP BY a;
-EXPLAIN
-SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	Using filesort
-1	PRIMARY	<derived2>	ref	key0	key0	5	const	1	Using where
-2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	10	Using temporary; Using filesort
-SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
-a	b	a
-188	8	8
-255	8	8
-DROP VIEW v1;
-DROP TABLE t1,t2;
-#
-#  LP bug #800085: crash with a query using a simple derived table 
-#                  (fixed by the patch for bug 798621)
-#
-CREATE TABLE t1 (f1 int, f2 varchar(32)) ;
-INSERT INTO t1 VALUES (NULL,'j'), (8,'c');
-CREATE TABLE t2 (f1 int);
-INSERT INTO t2 VALUES (1), (5);
-SELECT DISTINCT t.f1 FROM (SELECT * FROM t1) AS t, t2
-WHERE t.f2='s' AND t.f2 LIKE '%a%' OR t.f1<>0 ORDER BY t.f2;
-f1
-8
-DROP TABLE t1, t2;
diff --git a/mysql-test/r/derived_opt.result b/mysql-test/r/derived_opt.result
new file mode 100644
index 00000000000..38f9edbbb2d
--- /dev/null
+++ b/mysql-test/r/derived_opt.result
@@ -0,0 +1,255 @@
+drop table if exists t1,t2,t3;
+set @exit_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on,derived_with_keys=on';
+set @save_optimizer_switch=@@optimizer_switch;
+CREATE TABLE t1 (a int not null, b char (10) not null);
+insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
+CREATE TABLE t2 (a int not null, b char (10) not null);
+insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
+CREATE TABLE t3 (a int not null, b char (10) not null);
+insert into t3 values (3,'f'),(4,'y'),(5,'z'),(6,'c');
+select * from t1 as x1, (select * from t1) as x2;
+a	b	a	b
+1	a	1	a
+2	b	1	a
+3	c	1	a
+3	c	1	a
+1	a	2	b
+2	b	2	b
+3	c	2	b
+3	c	2	b
+1	a	3	c
+2	b	3	c
+3	c	3	c
+3	c	3	c
+1	a	3	c
+2	b	3	c
+3	c	3	c
+3	c	3	c
+explain select * from t1 as x1, (select * from t1) as x2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	x1	ALL	NULL	NULL	NULL	NULL	4	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
+drop table if exists  t2,t3;
+CREATE TABLE t2 (a int not null);
+insert into t2 values(1);
+select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
+a	b	t2a
+1	a	1
+explain select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	system	NULL	NULL	NULL	NULL	1	
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where
+drop table t1, t2;
+create table t1(a int not null, t char(8), index(a));
+SELECT * FROM (SELECT * FROM t1) as b ORDER BY a  ASC LIMIT 0,20;
+a	t
+1	1
+2	2
+3	3
+4	4
+5	5
+6	6
+7	7
+8	8
+9	9
+10	10
+11	11
+12	12
+13	13
+14	14
+15	15
+16	16
+17	17
+18	18
+19	19
+20	20
+explain select count(*) from t1 as tt1, (select * from t1) as tt2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+drop table t1;
+create table t1 (mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, matintnum CHAR(6) NOT NULL, test MEDIUMINT UNSIGNED NULL);
+create table t2 (mat_id MEDIUMINT UNSIGNED NOT NULL, pla_id MEDIUMINT UNSIGNED NOT NULL);
+insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4), (NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8), (NULL, 'i', 9);
+insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
+SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+pla_id	mat_id
+102	1
+101	1
+100	1
+104	2
+103	2
+105	3
+SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+pla_id	test
+102	1
+101	1
+100	1
+104	2
+103	2
+105	3
+explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
+1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
+2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
+explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
+1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
+2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
+2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
+drop table t1,t2;
+create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
+);
+insert into t1 VALUES(1,1,1), (2,2,1);
+select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
+count(*)
+2
+explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	2	Using where
+1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.A.E2	1	Using where
+3	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	2	Using where
+drop table t1;
+create table t1 (a int);
+insert into t1 values (1),(2);
+select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
+a	a
+1	1
+2	1
+1	2
+2	2
+explain select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<derived4>	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
+4	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
+5	UNION	t1	ALL	NULL	NULL	NULL	NULL	2	
+NULL	UNION RESULT	<union4,5>	ALL	NULL	NULL	NULL	NULL	NULL	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
+3	UNION	t1	ALL	NULL	NULL	NULL	NULL	2	
+NULL	UNION RESULT	<union2,3>	ALL	NULL	NULL	NULL	NULL	NULL	
+drop table t1;
+create table t2 (a int, b int, primary key (a));
+insert into t2 values (1,7),(2,7);
+explain select a from t2 where a>1;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
+explain select a from (select a from t2 where a>1) tt;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
+drop table t2;
+create table t1 
+(
+c1  tinyint, c2  smallint, c3  mediumint, c4  int,
+c5  integer, c6  bigint, c7  float, c8  double,
+c9  double precision, c10 real, c11 decimal(7, 4), c12 numeric(8, 4),
+c13 date, c14 datetime, c15 timestamp, c16 time,
+c17 year, c18 bit, c19 bool, c20 char,
+c21 char(10), c22 varchar(30), c23 tinyblob, c24 tinytext,
+c25 blob, c26 text, c27 mediumblob, c28 mediumtext,
+c29 longblob, c30 longtext, c31 enum('one', 'two', 'three'),
+c32 set('monday', 'tuesday', 'wednesday')
+) engine = MYISAM ;
+create table t2 like t1;
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch="partial_match_rowid_merge=off,partial_match_table_scan=off";
+set @stmt= ' explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25 ' ;
+prepare stmt1 from @stmt ;
+execute stmt1 ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+5	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+4	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+execute stmt1 ;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+5	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+4	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+5	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+4	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+deallocate prepare stmt1;
+drop tables t1,t2;
+set @@optimizer_switch=@save_optimizer_switch;
+#
+#  LP bug #793436: query with a derived table for which optimizer proves
+#                  that it contains not more than 1 row
+#
+CREATE TABLE t1 (a int, KEY (a)) ;
+INSERT INTO t1 VALUES (3), (1);
+CREATE TABLE t2 (a int);
+INSERT INTO t2 VALUES (3);
+EXPLAIN
+SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	1	
+1	PRIMARY	t1	ref	a	a	5	const	1	Using index
+2	DERIVED	t2	system	NULL	NULL	NULL	NULL	1	
+SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
+a	a
+3	3
+DROP TABLE t1,t2;
+#
+#  LP bug #800518: crash with a query over a derived table
+#                  when a min/max optimization is applied
+#
+CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
+INSERT INTO t1 VALUES 
+(100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
+(200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
+EXPLAIN
+SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
+SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
+MAX(b)
+5
+DROP TABLE t1;
+#
+#  LP bug #799499: query over a materialized view 
+#                  accessed by a key
+#
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (8);
+CREATE TABLE t2 (a int, b int) ;
+INSERT INTO t2 VALUES
+(262, NULL), (253, 190), (260, NULL), (250, 163), (188, 8),
+(257,200), (256, NULL), (255, 8), (249, NULL), (259, 7);
+CREATE VIEW v1 AS SELECT a, MIN(b) AS b FROM t2 GROUP BY a;
+EXPLAIN
+SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	PRIMARY	t1	system	NULL	NULL	NULL	NULL	1	Using filesort
+1	PRIMARY	<derived2>	ref	key0	key0	5	const	1	Using where
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	10	Using temporary; Using filesort
+SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
+a	b	a
+188	8	8
+255	8	8
+DROP VIEW v1;
+DROP TABLE t1,t2;
+#
+#  LP bug #800085: crash with a query using a simple derived table 
+#                  (fixed by the patch for bug 798621)
+#
+CREATE TABLE t1 (f1 int, f2 varchar(32)) ;
+INSERT INTO t1 VALUES (NULL,'j'), (8,'c');
+CREATE TABLE t2 (f1 int);
+INSERT INTO t2 VALUES (1), (5);
+SELECT DISTINCT t.f1 FROM (SELECT * FROM t1) AS t, t2
+WHERE t.f2='s' AND t.f2 LIKE '%a%' OR t.f1<>0 ORDER BY t.f2;
+f1
+8
+DROP TABLE t1, t2;
+set optimizer_switch=@exit_optimizer_switch;
diff --git a/mysql-test/r/derived_view.result b/mysql-test/r/derived_view.result
index 5a53f560a46..4e9d979804b 100644
--- a/mysql-test/r/derived_view.result
+++ b/mysql-test/r/derived_view.result
@@ -1,5 +1,8 @@
 drop table if exists t1,t2;
 drop view if exists v1,v2,v3,v4;
+set @exit_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on,derived_with_keys=on';
+set @save_optimizer_switch=@@optimizer_switch;
 create table t1(f1 int, f11 int);
 create table t2(f2 int, f22 int);
 insert into t1 values(1,1),(2,2),(3,3),(5,5),(9,9),(7,7);
@@ -787,7 +790,7 @@ a
 1
 2
 1
-SET SESSION optimizer_switch=default;
+SET SESSION optimizer_switch=@save_optimizer_switch;
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
 #
@@ -843,7 +846,7 @@ a	b	a	b
 0	0	1	0
 0	0	3	0
 0	0	0	0
-SET SESSION optimizer_switch=default;
+SET SESSION optimizer_switch=@save_optimizer_switch;
 DROP VIEW v1;
 DROP TABLE t1;
 #
@@ -1166,3 +1169,35 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 NULL	UNION RESULT	<union3,4>	ALL	NULL	NULL	NULL	NULL	NULL	
 DROP VIEW v1,v2;
 DROP TABLE t1,t2,t3;
+#
+# LP bug #804686: query over a derived table using a view 
+#                 with a degenerated where condition
+#
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (0,0), (1,0), (0,0), (1,1), (1,0);
+CREATE VIEW v1 AS SELECT a,b FROM t1;
+CREATE VIEW v2 AS SELECT a, MAX(b) AS b FROM t1 GROUP BY a;
+SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b<>0;
+b
+SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b<>0;
+b
+SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
+b
+SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
+b
+EXPLAIN EXTENDED
+SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+Warnings:
+Note	1003	select `test`.`t1`.`b` AS `b` from `test`.`t1` where 0
+EXPLAIN EXTENDED
+SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
+1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
+3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using temporary; Using filesort
+Warnings:
+Note	1003	select `v2`.`b` AS `b` from `test`.`v2` where 0
+DROP VIEW v1,v2;
+DROP TABLE t1;
+set optimizer_switch=@exit_optimizer_switch;
diff --git a/mysql-test/r/explain.result b/mysql-test/r/explain.result
index 7bfb090f659..dbd0967da20 100644
--- a/mysql-test/r/explain.result
+++ b/mysql-test/r/explain.result
@@ -312,7 +312,8 @@ INSERT INTO t2 VALUES (8);
 EXPLAIN EXTENDED
 SELECT * FROM ( SELECT t1.a FROM t1,t2 WHERE t2.a = t1.a ) AS t;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	0	0.00	const row not found
+2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 Warnings:
-Note	1003	select NULL AS `a` from `test`.`t1` join `test`.`t2` where 0
+Note	1003	select NULL AS `a` from (select NULL AS `a` from `test`.`t1` join `test`.`t2` where 0) `t`
 DROP TABLE t1,t2;
diff --git a/mysql-test/r/func_group.result b/mysql-test/r/func_group.result
index 24e146159ea..4c81cf63b6e 100644
--- a/mysql-test/r/func_group.result
+++ b/mysql-test/r/func_group.result
@@ -1928,8 +1928,9 @@ HAVING ('m') IN (
 SELECT v
 FROM t2);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	empty1	system	NULL	NULL	NULL	NULL	0	const row not found
+1	PRIMARY	<derived2>	system	NULL	NULL	NULL	NULL	0	const row not found
 3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
+2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 
 #
 # 5) Test that subquery materialization is setup for query with
diff --git a/mysql-test/r/func_str.result b/mysql-test/r/func_str.result
index 6c84ebaa18b..f23026096a5 100644
--- a/mysql-test/r/func_str.result
+++ b/mysql-test/r/func_str.result
@@ -2549,12 +2549,14 @@ create table t1(f1 tinyint default null)engine=myisam;
 insert into t1 values (-1),(null);
 explain select 1 as a from t1,(select decode(f1,f1) as b from t1) a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
 explain select 1 as a from t1,(select encode(f1,f1) as b from t1) a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	
 drop table t1;
 #
 # Bug#49141: Encode function is significantly slower in 5.1 compared to 5.0
diff --git a/mysql-test/r/index_merge_innodb.result b/mysql-test/r/index_merge_innodb.result
index d935cdbddbc..b484afca73b 100644
--- a/mysql-test/r/index_merge_innodb.result
+++ b/mysql-test/r/index_merge_innodb.result
@@ -691,7 +691,8 @@ SELECT COUNT(*) FROM
 (SELECT * FROM t1 FORCE INDEX(primary,idx)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index_merge	PRIMARY,idx	idx,PRIMARY	5,4	NULL	11419	Using sort_union(idx,PRIMARY); Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11419	
+2	DERIVED	t1	index_merge	PRIMARY,idx	idx,PRIMARY	5,4	NULL	11419	Using sort_union(idx,PRIMARY); Using where
 SELECT COUNT(*) FROM 
 (SELECT * FROM t1 FORCE INDEX(primary,idx)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
@@ -702,7 +703,8 @@ SELECT COUNT(*) FROM
 (SELECT * FROM t1 IGNORE INDEX(idx)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	#	Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	#	
+2	DERIVED	t1	ALL	PRIMARY	NULL	NULL	NULL	#	Using where
 SELECT COUNT(*) FROM 
 (SELECT * FROM t1 IGNORE INDEX(idx)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
diff --git a/mysql-test/r/index_merge_myisam.result b/mysql-test/r/index_merge_myisam.result
index 7566c94bc2d..2ed58245b54 100644
--- a/mysql-test/r/index_merge_myisam.result
+++ b/mysql-test/r/index_merge_myisam.result
@@ -287,7 +287,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 NULL	UNION RESULT	<union1,2>	ALL	NULL	NULL	NULL	NULL	NULL	
 explain select * from (select * from t1 where key1 = 3 or key2 =3) as Z where key8 >5;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index_merge	i1,i2,i8	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	DERIVED	t1	index_merge	i1,i2	i1,i2	4,4	NULL	2	Using union(i1,i2); Using where
 create table t3 like t0;
 insert into t3 select * from t0;
 alter table t3 add key9 int not null, add index i9(key9);
diff --git a/mysql-test/r/information_schema.result b/mysql-test/r/information_schema.result
index 87675143853..1f56ee4d53b 100644
--- a/mysql-test/r/information_schema.result
+++ b/mysql-test/r/information_schema.result
@@ -1288,7 +1288,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	tables	ALL	NULL	NULL	NULL	NULL	NULL	Open_frm_only; Scanned all databases; Using filesort
 explain select * from (select table_name from information_schema.tables) as a;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	tables	ALL	NULL	NULL	NULL	NULL	NULL	Skip_open_table; Scanned all databases
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+2	DERIVED	tables	ALL	NULL	NULL	NULL	NULL	NULL	Skip_open_table; Scanned all databases
 drop view v1;
 create table t1 (f1 int(11));
 create table t2 (f1 int(11), f2 int(11));
diff --git a/mysql-test/r/join_cache.result b/mysql-test/r/join_cache.result
index 1dbefde79e8..b544772f383 100644
--- a/mysql-test/r/join_cache.result
+++ b/mysql-test/r/join_cache.result
@@ -4972,7 +4972,7 @@ DROP TABLE t1,t2;
 # Bug #802860: crash on join cache + derived + duplicate_weedout 
 #
 SET SESSION optimizer_switch=
-'semijoin=on,materialization=off,firstmatch=off,loosescan=off';
+'semijoin=on,materialization=off,firstmatch=off,loosescan=off,derived_with_keys=on';
 CREATE TABLE t1 (a int) ;
 INSERT IGNORE INTO t1 VALUES (0), (1), (0);
 CREATE TABLE t2 (a int) ;
diff --git a/mysql-test/r/optimizer_switch.result b/mysql-test/r/optimizer_switch.result
index 62cfd32d94c..342f28243ad 100644
--- a/mysql-test/r/optimizer_switch.result
+++ b/mysql-test/r/optimizer_switch.result
@@ -4,19 +4,19 @@
 #
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='index_merge=off,index_merge_union=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='index_merge_union=on';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,index_merge_sort_union=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=off,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch=4;
 ERROR 42000: Variable 'optimizer_switch' can't be set to the value of '4'
 set optimizer_switch=NULL;
@@ -43,60 +43,60 @@ set optimizer_switch=default;
 set optimizer_switch='index_merge=off,index_merge_union=off,default';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=off,index_merge_union=off,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch=default;
 select @@global.optimizer_switch;
 @@global.optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set @@global.optimizer_switch=default;
 select @@global.optimizer_switch;
 @@global.optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 #
 # Check index_merge's @@optimizer_switch flags
 #
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 
 BUG#37120 optimizer_switch allowable values not according to specification
 
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,materialization=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,semijoin=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,semijoin=off,materialization=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,materialization=off,semijoin=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,semijoin=off,materialization=off,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,semijoin=off,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch='default,materialization=off,loosescan=off';
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
 set optimizer_switch=default;
 select @@optimizer_switch;
 @@optimizer_switch
-index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=on,derived_with_keys=on,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
+index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,index_condition_pushdown=off,derived_merge=off,derived_with_keys=off,firstmatch=off,loosescan=off,materialization=off,in_to_exists=on,semijoin=off,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=off,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=off,semijoin_with_cache=off,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off
diff --git a/mysql-test/r/ps.result b/mysql-test/r/ps.result
index 5197aea9e87..ca847188ce9 100644
--- a/mysql-test/r/ps.result
+++ b/mysql-test/r/ps.result
@@ -156,6 +156,7 @@ prepare stmt1 from @stmt ;
 execute stmt1 ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+6	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 5	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 4	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -163,6 +164,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 execute stmt1 ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+6	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 5	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 4	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
@@ -170,6 +172,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+6	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 5	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 4	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
diff --git a/mysql-test/r/ps_2myisam.result b/mysql-test/r/ps_2myisam.result
index 2a9d08a70f4..2de0c0bfd73 100644
--- a/mysql-test/r/ps_2myisam.result
+++ b/mysql-test/r/ps_2myisam.result
@@ -902,6 +902,8 @@ a	(select count(distinct t5.b) as sum from t5, t6
 1	2
 drop table t5, t6, t7 ;
 drop table if exists t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 set @stmt= ' SELECT
    (SELECT SUM(c1 + c12 + 0.0) FROM t2 
@@ -951,6 +953,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 @arg07, @arg08, @arg09 ;
 drop table t2 ;
+set optimizer_switch=@save_optimizer_switch;
 select 1 < (select a from t1) ;
 ERROR 21000: Subquery returns more than 1 row
 prepare stmt1 from ' select 1 < (select a from t1) ' ;
diff --git a/mysql-test/r/ps_3innodb.result b/mysql-test/r/ps_3innodb.result
index 6b7434390af..701c7528cca 100644
--- a/mysql-test/r/ps_3innodb.result
+++ b/mysql-test/r/ps_3innodb.result
@@ -902,6 +902,8 @@ a	(select count(distinct t5.b) as sum from t5, t6
 1	2
 drop table t5, t6, t7 ;
 drop table if exists t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 set @stmt= ' SELECT
    (SELECT SUM(c1 + c12 + 0.0) FROM t2 
@@ -951,6 +953,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 @arg07, @arg08, @arg09 ;
 drop table t2 ;
+set optimizer_switch=@save_optimizer_switch;
 select 1 < (select a from t1) ;
 ERROR 21000: Subquery returns more than 1 row
 prepare stmt1 from ' select 1 < (select a from t1) ' ;
diff --git a/mysql-test/r/ps_4heap.result b/mysql-test/r/ps_4heap.result
index 58acc19124a..91be8c59493 100644
--- a/mysql-test/r/ps_4heap.result
+++ b/mysql-test/r/ps_4heap.result
@@ -903,6 +903,8 @@ a	(select count(distinct t5.b) as sum from t5, t6
 1	2
 drop table t5, t6, t7 ;
 drop table if exists t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 set @stmt= ' SELECT
    (SELECT SUM(c1 + c12 + 0.0) FROM t2 
@@ -952,6 +954,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 @arg07, @arg08, @arg09 ;
 drop table t2 ;
+set optimizer_switch=@save_optimizer_switch;
 select 1 < (select a from t1) ;
 ERROR 21000: Subquery returns more than 1 row
 prepare stmt1 from ' select 1 < (select a from t1) ' ;
diff --git a/mysql-test/r/ps_5merge.result b/mysql-test/r/ps_5merge.result
index 654e641deeb..e851127b7bd 100644
--- a/mysql-test/r/ps_5merge.result
+++ b/mysql-test/r/ps_5merge.result
@@ -945,6 +945,8 @@ a	(select count(distinct t5.b) as sum from t5, t6
 1	2
 drop table t5, t6, t7 ;
 drop table if exists t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 set @stmt= ' SELECT
    (SELECT SUM(c1 + c12 + 0.0) FROM t2 
@@ -994,6 +996,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 @arg07, @arg08, @arg09 ;
 drop table t2 ;
+set optimizer_switch=@save_optimizer_switch;
 select 1 < (select a from t1) ;
 ERROR 21000: Subquery returns more than 1 row
 prepare stmt1 from ' select 1 < (select a from t1) ' ;
@@ -4299,6 +4302,8 @@ a	(select count(distinct t5.b) as sum from t5, t6
 1	2
 drop table t5, t6, t7 ;
 drop table if exists t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 set @stmt= ' SELECT
    (SELECT SUM(c1 + c12 + 0.0) FROM t2 
@@ -4348,6 +4353,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 @arg07, @arg08, @arg09 ;
 drop table t2 ;
+set optimizer_switch=@save_optimizer_switch;
 select 1 < (select a from t1) ;
 ERROR 21000: Subquery returns more than 1 row
 prepare stmt1 from ' select 1 < (select a from t1) ' ;
diff --git a/mysql-test/r/subselect.result b/mysql-test/r/subselect.result
index 57cdb069934..331f4baa5be 100644
--- a/mysql-test/r/subselect.result
+++ b/mysql-test/r/subselect.result
@@ -204,10 +204,11 @@ select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 (select * from t2 where a>1) as tt;
 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
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using filesort
 Warnings:
-Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`test`.`t2`.`a` AS `a` from `test`.`t2` where (`test`.`t2`.`a` > 1)
+Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`tt`.`a` AS `a` from (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` > 1)) `tt`
 select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
 a
 2
diff --git a/mysql-test/r/subselect3.result b/mysql-test/r/subselect3.result
index da60eb16802..4bb2e524861 100644
--- a/mysql-test/r/subselect3.result
+++ b/mysql-test/r/subselect3.result
@@ -1115,8 +1115,9 @@ a
 set @@optimizer_switch=@save_optimizer_switch;
 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	t0	ALL	NULL	NULL	NULL	NULL	11	
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(t0)
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(<derived2>)
+2	DERIVED	t0	ALL	NULL	NULL	NULL	NULL	11	
 drop table t0, t1;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
diff --git a/mysql-test/r/subselect3_jcl6.result b/mysql-test/r/subselect3_jcl6.result
index 2d2c0b342ba..6e739ee983a 100644
--- a/mysql-test/r/subselect3_jcl6.result
+++ b/mysql-test/r/subselect3_jcl6.result
@@ -1124,8 +1124,9 @@ a
 set @@optimizer_switch=@save_optimizer_switch;
 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	t0	ALL	NULL	NULL	NULL	NULL	11	
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(t0); Using join buffer (flat, BNL join)
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
+1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(<derived2>); Using join buffer (flat, BNL join)
+2	DERIVED	t0	ALL	NULL	NULL	NULL	NULL	11	
 drop table t0, t1;
 create table t0 (a int);
 insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
diff --git a/mysql-test/r/subselect_mat_cost_bugs.result b/mysql-test/r/subselect_mat_cost_bugs.result
index ed86ae5c7b9..f49d2f182ef 100644
--- a/mysql-test/r/subselect_mat_cost_bugs.result
+++ b/mysql-test/r/subselect_mat_cost_bugs.result
@@ -156,13 +156,15 @@ WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 3	SUBQUERY	t1	index	NULL	f3	5	NULL	2	Using index
+2	DERIVED	NULL	NULL	NULL	NULL	NULL	NULL	NULL	no matching row in const table
 insert into t2 values (1),(2);
 EXPLAIN
 SELECT * FROM (SELECT * FROM t2) AS a2
 WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
 3	SUBQUERY	t1	index	NULL	f3	5	NULL	2	Using index
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	
 drop table t1,t2;
 #
 # LP BUG#715027 Assertion `!table || (!table->read_set || bitmap_is_set(table->read_set, field_index))' failed
@@ -181,10 +183,11 @@ WHERE t1.f1 AND alias2.f10
 )
 ORDER BY field1 ;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	Using where; Using filesort
-1	PRIMARY	alias1	eq_ref	PRIMARY	PRIMARY	4	test.t2.f3	1	Using index
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	Using where; Using filesort
+1	PRIMARY	alias1	eq_ref	PRIMARY	PRIMARY	4	alias2.f3	1	Using index
 3	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	
 3	DEPENDENT SUBQUERY	t1	index	NULL	PRIMARY	4	NULL	2	Using where; Using index; Using join buffer (flat, BNL join)
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	
 SELECT alias2.f2 AS field1
 FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
 WHERE (
diff --git a/mysql-test/r/subselect_no_mat.result b/mysql-test/r/subselect_no_mat.result
index b0f9be93580..a22b7e74e17 100644
--- a/mysql-test/r/subselect_no_mat.result
+++ b/mysql-test/r/subselect_no_mat.result
@@ -209,10 +209,11 @@ select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 (select * from t2 where a>1) as tt;
 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
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using filesort
 Warnings:
-Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`test`.`t2`.`a` AS `a` from `test`.`t2` where (`test`.`t2`.`a` > 1)
+Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`tt`.`a` AS `a` from (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` > 1)) `tt`
 select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
 a
 2
diff --git a/mysql-test/r/subselect_no_opts.result b/mysql-test/r/subselect_no_opts.result
index b03998c0e94..0ce023c6137 100644
--- a/mysql-test/r/subselect_no_opts.result
+++ b/mysql-test/r/subselect_no_opts.result
@@ -205,10 +205,11 @@ select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 (select * from t2 where a>1) as tt;
 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
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using filesort
 Warnings:
-Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`test`.`t2`.`a` AS `a` from `test`.`t2` where (`test`.`t2`.`a` > 1)
+Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`tt`.`a` AS `a` from (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` > 1)) `tt`
 select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
 a
 2
diff --git a/mysql-test/r/subselect_no_semijoin.result b/mysql-test/r/subselect_no_semijoin.result
index 3c30e6d9954..bf380cf88e5 100644
--- a/mysql-test/r/subselect_no_semijoin.result
+++ b/mysql-test/r/subselect_no_semijoin.result
@@ -205,10 +205,11 @@ select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 (select * from t2 where a>1) as tt;
 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
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using filesort
 Warnings:
-Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`test`.`t2`.`a` AS `a` from `test`.`t2` where (`test`.`t2`.`a` > 1)
+Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`tt`.`a` AS `a` from (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` > 1)) `tt`
 select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
 a
 2
diff --git a/mysql-test/r/subselect_partial_match.result b/mysql-test/r/subselect_partial_match.result
index ed30fcfc95a..85aa96df714 100644
--- a/mysql-test/r/subselect_partial_match.result
+++ b/mysql-test/r/subselect_partial_match.result
@@ -226,10 +226,11 @@ set @@optimizer_switch='materialization=on,semijoin=off,partial_match_rowid_merg
 EXPLAIN EXTENDED
 SELECT * FROM (SELECT * FROM t1 WHERE a1 NOT IN (SELECT b2 FROM t2)) table1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 3	SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	
 Warnings:
-Note	1003	select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (not(<in_optimizer>(`test`.`t1`.`a1`,`test`.`t1`.`a1` in ( <materialize> (select `test`.`t2`.`b2` from `test`.`t2` ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `<subquery3>`.`b2`)))))))
+Note	1003	select `table1`.`a1` AS `a1`,`table1`.`a2` AS `a2` from (select `test`.`t1`.`a1` AS `a1`,`test`.`t1`.`a2` AS `a2` from `test`.`t1` where (not(<in_optimizer>(`test`.`t1`.`a1`,`test`.`t1`.`a1` in ( <materialize> (select `test`.`t2`.`b2` from `test`.`t2` ), <primary_index_lookup>(`test`.`t1`.`a1` in <temporary table> on distinct_key where ((`test`.`t1`.`a1` = `<subquery3>`.`b2`)))))))) `table1`
 DROP TABLE t1, t2;
 #
 # LP BUG#613009 Crash in Ordered_key::get_field_idx
diff --git a/mysql-test/r/subselect_scache.result b/mysql-test/r/subselect_scache.result
index 615e10a4947..907b65abfed 100644
--- a/mysql-test/r/subselect_scache.result
+++ b/mysql-test/r/subselect_scache.result
@@ -208,10 +208,11 @@ select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 (select * from t2 where a>1) as tt;
 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
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using filesort
 Warnings:
-Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`test`.`t2`.`a` AS `a` from `test`.`t2` where (`test`.`t2`.`a` > 1)
+Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`tt`.`a` AS `a` from (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` > 1)) `tt`
 select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
 a
 2
diff --git a/mysql-test/r/view.result b/mysql-test/r/view.result
index b09c00a883c..67329370020 100644
--- a/mysql-test/r/view.result
+++ b/mysql-test/r/view.result
@@ -4247,37 +4247,6 @@ a	MIN(b)
 DROP VIEW v1;
 DROP TABLE t1,t2;
 #
-# LP bug #804686: query over a derived table using a view 
-#                 with a degenerated where condition
-#
-CREATE TABLE t1 (a int, b int);
-INSERT INTO t1 VALUES (0,0), (1,0), (0,0), (1,1), (1,0);
-CREATE VIEW v1 AS SELECT a,b FROM t1;
-CREATE VIEW v2 AS SELECT a, MAX(b) AS b FROM t1 GROUP BY a;
-SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b<>0;
-b
-SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b<>0;
-b
-SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
-b
-SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
-b
-EXPLAIN EXTENDED
-SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
-Warnings:
-Note	1003	select `test`.`t1`.`b` AS `b` from `test`.`t1` where 0
-EXPLAIN EXTENDED
-SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
-id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
-1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
-3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	100.00	Using temporary; Using filesort
-Warnings:
-Note	1003	select `v2`.`b` AS `b` from `test`.`v2` where 0
-DROP VIEW v1,v2;
-DROP TABLE t1;
-#
 # LP bug #793386: unexpected 'Duplicate column name ''' error
 #                 at the second execution of a PS using a view 
 #
diff --git a/mysql-test/suite/innodb/r/innodb_lock_wait_timeout_1.result b/mysql-test/suite/innodb/r/innodb_lock_wait_timeout_1.result
index 051266c526e..bd8760b8f79 100644
--- a/mysql-test/suite/innodb/r/innodb_lock_wait_timeout_1.result
+++ b/mysql-test/suite/innodb/r/innodb_lock_wait_timeout_1.result
@@ -104,7 +104,7 @@ id	1
 select_type	PRIMARY
 table	<derived2>
 type	ALL
-possible_keys	key0
+possible_keys	NULL
 key	NULL
 key_len	NULL
 ref	NULL
@@ -308,7 +308,7 @@ id	1
 select_type	PRIMARY
 table	<derived2>
 type	ALL
-possible_keys	key0
+possible_keys	NULL
 key	NULL
 key_len	NULL
 ref	NULL
diff --git a/mysql-test/suite/innodb/r/innodb_mysql.result b/mysql-test/suite/innodb/r/innodb_mysql.result
index 9acc1f424d4..971ff59e106 100644
--- a/mysql-test/suite/innodb/r/innodb_mysql.result
+++ b/mysql-test/suite/innodb/r/innodb_mysql.result
@@ -2656,7 +2656,8 @@ SELECT COUNT(*) FROM
 (SELECT * FROM t1 FORCE INDEX (idx,PRIMARY)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index_merge	PRIMARY,idx	idx,PRIMARY	5,4	NULL	3537	Using sort_union(idx,PRIMARY); Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	3537	
+2	DERIVED	t1	index_merge	PRIMARY,idx	idx,PRIMARY	5,4	NULL	3537	Using sort_union(idx,PRIMARY); Using where
 SELECT COUNT(*) FROM
 (SELECT * FROM t1 FORCE INDEX (idx,PRIMARY)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
diff --git a/mysql-test/suite/innodb_plugin/r/innodb_lock_wait_timeout_1.result b/mysql-test/suite/innodb_plugin/r/innodb_lock_wait_timeout_1.result
index 051266c526e..bd8760b8f79 100644
--- a/mysql-test/suite/innodb_plugin/r/innodb_lock_wait_timeout_1.result
+++ b/mysql-test/suite/innodb_plugin/r/innodb_lock_wait_timeout_1.result
@@ -104,7 +104,7 @@ id	1
 select_type	PRIMARY
 table	<derived2>
 type	ALL
-possible_keys	key0
+possible_keys	NULL
 key	NULL
 key_len	NULL
 ref	NULL
@@ -308,7 +308,7 @@ id	1
 select_type	PRIMARY
 table	<derived2>
 type	ALL
-possible_keys	key0
+possible_keys	NULL
 key	NULL
 key_len	NULL
 ref	NULL
diff --git a/mysql-test/suite/innodb_plugin/r/innodb_mysql.result b/mysql-test/suite/innodb_plugin/r/innodb_mysql.result
index df23048f834..27deb87ebef 100644
--- a/mysql-test/suite/innodb_plugin/r/innodb_mysql.result
+++ b/mysql-test/suite/innodb_plugin/r/innodb_mysql.result
@@ -2440,7 +2440,8 @@ SELECT COUNT(*) FROM
 (SELECT * FROM t1 FORCE INDEX (idx,PRIMARY)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	index_merge	PRIMARY,idx	idx,PRIMARY	5,4	NULL	3537	Using sort_union(idx,PRIMARY); Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	3537	
+2	DERIVED	t1	index_merge	PRIMARY,idx	idx,PRIMARY	5,4	NULL	3537	Using sort_union(idx,PRIMARY); Using where
 SELECT COUNT(*) FROM
 (SELECT * FROM t1 FORCE INDEX (idx,PRIMARY)
 WHERE a BETWEEN 2 AND 7 OR pk=1000000) AS t;
diff --git a/mysql-test/suite/maria/r/ps_maria.result b/mysql-test/suite/maria/r/ps_maria.result
index 8ac0fee6f50..6d0af4596de 100644
--- a/mysql-test/suite/maria/r/ps_maria.result
+++ b/mysql-test/suite/maria/r/ps_maria.result
@@ -902,6 +902,8 @@ a	(select count(distinct t5.b) as sum from t5, t6
 1	2
 drop table t5, t6, t7 ;
 drop table if exists t2 ;
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 create table t2 as select * from t9;
 set @stmt= ' SELECT
    (SELECT SUM(c1 + c12 + 0.0) FROM t2 
@@ -951,6 +953,7 @@ execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 execute stmt1 using @arg00, @arg01, @arg02, @arg03, @arg04, @arg05, @arg06,
 @arg07, @arg08, @arg09 ;
 drop table t2 ;
+set optimizer_switch=@save_optimizer_switch;
 select 1 < (select a from t1) ;
 ERROR 21000: Subquery returns more than 1 row
 prepare stmt1 from ' select 1 < (select a from t1) ' ;
diff --git a/mysql-test/suite/pbxt/r/derived.result b/mysql-test/suite/pbxt/r/derived.result
index b4c1762e81a..75d5fcf8b16 100644
--- a/mysql-test/suite/pbxt/r/derived.result
+++ b/mysql-test/suite/pbxt/r/derived.result
@@ -57,8 +57,9 @@ a	b	a	b
 3	c	3	c
 explain select * from t1 as x1, (select * from t1) as x2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	x1	ALL	NULL	NULL	NULL	NULL	4	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
+1	PRIMARY	x1	ALL	NULL	NULL	NULL	NULL	4	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	4	
 drop table if exists  t2,t3;
 select * from (select 1) as a;
 1
@@ -112,8 +113,9 @@ a	b
 3	c
 explain select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	1	
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	4	
+2	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	1	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	4	Using where; Using join buffer (flat, BNL join)
 drop table t1, t2;
 create table t1(a int not null, t char(8), index(a));
 SELECT * FROM (SELECT * FROM t1) as b ORDER BY a  ASC LIMIT 0,20;
@@ -140,8 +142,9 @@ a	t
 20	20
 explain select count(*) from t1 as tt1, (select * from t1) as tt2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	tt1	index	NULL	a	4	NULL	10000	Using index
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10000	Using join buffer (flat, BNL join)
+1	PRIMARY	tt1	index	NULL	a	4	NULL	10000	Using index
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	10000	Using join buffer (flat, BNL join)
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	10000	
 drop table t1;
 SELECT * FROM (SELECT (SELECT * FROM (SELECT 1 as a) as a )) as b;
 (SELECT * FROM (SELECT 1 as a) as a )
@@ -170,30 +173,30 @@ insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd'
 insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
 SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 pla_id	mat_id
-102	1
-101	1
 100	1
-104	2
+101	1
+102	1
 103	2
+104	2
 105	3
 SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 pla_id	test
-102	1
-101	1
 100	1
-104	2
+101	1
+102	1
 103	2
+104	2
 105	3
 explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
-1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
+1	PRIMARY	<derived2>	ALL	NULL	$hj	7	test.m2.matintnum	9	Using where
 2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
 2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
 explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	m2	ALL	NULL	NULL	NULL	NULL	9	
-1	PRIMARY	<derived2>	ref	key0	key0	7	test.m2.matintnum	2	
+1	PRIMARY	<derived2>	ALL	NULL	$hj	7	test.m2.matintnum	9	Using where
 2	DERIVED	mp	ALL	NULL	NULL	NULL	NULL	9	Using temporary; Using filesort
 2	DERIVED	m1	eq_ref	PRIMARY	PRIMARY	3	test.mp.mat_id	1	
 drop table t1,t2;
@@ -231,8 +234,9 @@ count(*)
 2
 explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	A	ALL	NULL	NULL	NULL	NULL	2	Using where
-1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.A.E2	1	Using where
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+1	PRIMARY	t1	eq_ref	PRIMARY	PRIMARY	4	THEMAX.E2	1	Using where
+2	DERIVED	A	ALL	NULL	NULL	NULL	NULL	2	Using where
 3	DEPENDENT SUBQUERY	B	ALL	NULL	NULL	NULL	NULL	2	Using where
 drop table t1;
 create table t1 (a int);
@@ -322,7 +326,8 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
 explain select a from (select a from t2 where a>1) tt;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	2	
+2	DERIVED	t2	index	PRIMARY	PRIMARY	4	NULL	2	Using where; Using index
 drop table t2;
 CREATE TABLE `t1` ( `itemid` int(11) NOT NULL default '0', `grpid` varchar(15) NOT NULL default '', `vendor` int(11) NOT NULL default '0', `date_` date NOT NULL default '0000-00-00', `price` decimal(12,2) NOT NULL default '0.00', PRIMARY KEY  (`itemid`,`grpid`,`vendor`,`date_`), KEY `itemid` (`itemid`,`vendor`), KEY `itemid_2` (`itemid`,`date_`));
 insert into t1 values (128, 'rozn', 2, now(), 10),(128, 'rozn', 1, now(), 10);
diff --git a/mysql-test/suite/pbxt/r/subselect.result b/mysql-test/suite/pbxt/r/subselect.result
index 1e0bbe65586..9b2db63a4b9 100644
--- a/mysql-test/suite/pbxt/r/subselect.result
+++ b/mysql-test/suite/pbxt/r/subselect.result
@@ -199,10 +199,11 @@ select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from
 explain extended select (select t3.a from t3 where a<8 order by 1 desc limit 1), a from 
 (select * from t2 where a>1) as tt;
 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
+1	PRIMARY	<derived3>	ALL	NULL	NULL	NULL	NULL	2	100.00	
+3	DERIVED	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using filesort
 Warnings:
-Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`test`.`t2`.`a` AS `a` from `test`.`t2` where (`test`.`t2`.`a` > 1)
+Note	1003	select (select `test`.`t3`.`a` from `test`.`t3` where (`test`.`t3`.`a` < 8) order by 1 desc limit 1) AS `(select t3.a from t3 where a<8 order by 1 desc limit 1)`,`tt`.`a` AS `a` from (select `test`.`t2`.`a` AS `a`,`test`.`t2`.`b` AS `b` from `test`.`t2` where (`test`.`t2`.`a` > 1)) `tt`
 select * from t1 where t1.a=(select t2.a from t2 where t2.b=(select max(a) from t3) order by 1 desc limit 1);
 a
 2
@@ -2626,6 +2627,8 @@ createDate datetime NOT NULL,
 modifyDate timestamp NOT NULL
 );
 INSERT INTO t5 VALUES (5141,12,'2004-08-06','2004-08-06');
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
 select
 count(distinct t2.userid) pass,
 groupstuff.*,
@@ -2667,6 +2670,7 @@ pass	userid	parentid	parentgroup	childid	groupname	grouptypeid	crse	categoryid	c
 1	5141	12	group2	12	group2	5	1	1	87	Oct04
 1	5141	12	group2	12	group2	5	1	2	88	Oct04
 1	5141	12	group2	12	group2	5	1	2	89	Oct04
+set optimizer_switch=@save_optimizer_switch;
 drop table t1, t2, t3, t4, t5;
 create table t1 (a int);
 insert into t1 values (1), (2), (3);
diff --git a/mysql-test/suite/pbxt/t/subselect.test b/mysql-test/suite/pbxt/t/subselect.test
index 3f4d6a9a870..4c78d2f805b 100644
--- a/mysql-test/suite/pbxt/t/subselect.test
+++ b/mysql-test/suite/pbxt/t/subselect.test
@@ -1674,6 +1674,9 @@ CREATE TABLE t5 (
 );
 INSERT INTO t5 VALUES (5141,12,'2004-08-06','2004-08-06');
 
+set @save_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on';
+
 select
   count(distinct t2.userid) pass,
   groupstuff.*,
@@ -1706,6 +1709,8 @@ join
 group by 
   groupstuff.groupname, colhead , t2.courseid;
 
+set optimizer_switch=@save_optimizer_switch; 
+
 drop table t1, t2, t3, t4, t5;
 
 #
diff --git a/mysql-test/suite/vcol/r/vcol_select_innodb.result b/mysql-test/suite/vcol/r/vcol_select_innodb.result
index 7f7b1e40269..3e6a95caef1 100644
--- a/mysql-test/suite/vcol/r/vcol_select_innodb.result
+++ b/mysql-test/suite/vcol/r/vcol_select_innodb.result
@@ -98,7 +98,8 @@ a	b	c
 NULL	NULL	NULL
 explain select * from (select a,b,c from t1) as t11;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	5	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	
 ###
 ### Using aggregate functions with/without DISTINCT
 ###
diff --git a/mysql-test/suite/vcol/r/vcol_select_myisam.result b/mysql-test/suite/vcol/r/vcol_select_myisam.result
index cc327a818b4..657b79dc582 100644
--- a/mysql-test/suite/vcol/r/vcol_select_myisam.result
+++ b/mysql-test/suite/vcol/r/vcol_select_myisam.result
@@ -98,7 +98,8 @@ a	b	c
 NULL	NULL	NULL
 explain select * from (select a,b,c from t1) as t11;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
-1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	5	
+1	PRIMARY	<derived2>	ALL	NULL	NULL	NULL	NULL	5	
+2	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	5	
 ###
 ### Using aggregate functions with/without DISTINCT
 ###
diff --git a/mysql-test/t/derived.test b/mysql-test/t/derived.test
index 3cf8bd92512..962cec95add 100644
--- a/mysql-test/t/derived.test
+++ b/mysql-test/t/derived.test
@@ -315,73 +315,3 @@ WHERE j = SUBSTRING('12', (SELECT * FROM (SELECT MIN(j) FROM t1) t2))) t3;
 DROP TABLE t1;
 
 --echo # End of 5.0 tests
-
---echo #
---echo #  LP bug #793436: query with a derived table for which optimizer proves
---echo #                  that it contains not more than 1 row
---echo #
-
-CREATE TABLE t1 (a int, KEY (a)) ;
-INSERT INTO t1 VALUES (3), (1);
-CREATE TABLE t2 (a int);
-INSERT INTO t2 VALUES (3);
-
-EXPLAIN
-SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
-SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
-
-DROP TABLE t1,t2;
-
---echo #
---echo #  LP bug #800518: crash with a query over a derived table
---echo #                  when a min/max optimization is applied
---echo #
-
-CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
-INSERT INTO t1 VALUES 
-  (100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
-  (200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
-
-EXPLAIN
-SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
-SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
-
-DROP TABLE t1;
-
---echo #
---echo #  LP bug #799499: query over a materialized view 
---echo #                  accessed by a key
---echo #
-
-CREATE TABLE t1 (a int) ;
-INSERT INTO t1 VALUES (8);
-
-CREATE TABLE t2 (a int, b int) ;
-INSERT INTO t2 VALUES
-  (262, NULL), (253, 190), (260, NULL), (250, 163), (188, 8),
-  (257,200), (256, NULL), (255, 8), (249, NULL), (259, 7);
-
-CREATE VIEW v1 AS SELECT a, MIN(b) AS b FROM t2 GROUP BY a;
-
-EXPLAIN
-SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
-SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
-
-DROP VIEW v1;
-DROP TABLE t1,t2;
-
---echo #
---echo #  LP bug #800085: crash with a query using a simple derived table 
---echo #                  (fixed by the patch for bug 798621)
---echo #
-
-CREATE TABLE t1 (f1 int, f2 varchar(32)) ;
-INSERT INTO t1 VALUES (NULL,'j'), (8,'c');
-
-CREATE TABLE t2 (f1 int);
-INSERT INTO t2 VALUES (1), (5);
-
-SELECT DISTINCT t.f1 FROM (SELECT * FROM t1) AS t, t2
-  WHERE t.f2='s' AND t.f2 LIKE '%a%' OR t.f1<>0 ORDER BY t.f2;
-
-DROP TABLE t1, t2;
diff --git a/mysql-test/t/derived_opt.test b/mysql-test/t/derived_opt.test
new file mode 100644
index 00000000000..c45766e68f8
--- /dev/null
+++ b/mysql-test/t/derived_opt.test
@@ -0,0 +1,183 @@
+# Initialize
+--disable_warnings
+drop table if exists t1,t2,t3;
+--enable_warnings
+
+set @exit_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on,derived_with_keys=on';
+# The 'default' value within the scope of this test:
+set @save_optimizer_switch=@@optimizer_switch;
+
+CREATE TABLE t1 (a int not null, b char (10) not null);
+insert into t1 values(1,'a'),(2,'b'),(3,'c'),(3,'c');
+CREATE TABLE t2 (a int not null, b char (10) not null);
+insert into t2 values (3,'c'),(4,'d'),(5,'f'),(6,'e');
+CREATE TABLE t3 (a int not null, b char (10) not null);
+insert into t3 values (3,'f'),(4,'y'),(5,'z'),(6,'c');
+select * from t1 as x1, (select * from t1) as x2;
+explain select * from t1 as x1, (select * from t1) as x2;
+drop table if exists  t2,t3;
+
+CREATE TABLE t2 (a int not null);
+insert into t2 values(1);
+select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
+explain select * from (select t1.*, t2.a as t2a from t1,t2 where t1.a=t2.a) t1;
+drop table t1, t2;
+
+create table t1(a int not null, t char(8), index(a));
+--disable_query_log
+begin;
+let $1 = 10000;
+while ($1)
+ {
+  eval insert into t1 values ($1,'$1'); 
+  dec $1;
+ }
+commit;
+--enable_query_log
+SELECT * FROM (SELECT * FROM t1) as b ORDER BY a  ASC LIMIT 0,20;
+explain select count(*) from t1 as tt1, (select * from t1) as tt2;
+drop table t1;
+
+#
+# test->used_keys test for derived tables
+#
+create table t1 (mat_id MEDIUMINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, matintnum CHAR(6) NOT NULL, test MEDIUMINT UNSIGNED NULL);
+create table t2 (mat_id MEDIUMINT UNSIGNED NOT NULL, pla_id MEDIUMINT UNSIGNED NOT NULL);
+insert into t1 values (NULL, 'a', 1), (NULL, 'b', 2), (NULL, 'c', 3), (NULL, 'd', 4), (NULL, 'e', 5), (NULL, 'f', 6), (NULL, 'g', 7), (NULL, 'h', 8), (NULL, 'i', 9);
+insert into t2 values (1, 100), (1, 101), (1, 102), (2, 100), (2, 103), (2, 104), (3, 101), (3, 102), (3, 105);
+
+SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+
+explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2  INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
+drop table t1,t2;
+
+#
+# deived tables with subquery inside all by one table
+#
+create table t1 (E1 INTEGER UNSIGNED NOT NULL, E2 INTEGER UNSIGNED NOT NULL, E3 INTEGER UNSIGNED NOT NULL, PRIMARY KEY(E1)
+);
+insert into t1 VALUES(1,1,1), (2,2,1);
+select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
+explain select count(*) from t1 INNER JOIN (SELECT A.E1, A.E2, A.E3 FROM t1 AS A WHERE A.E3 = (SELECT MAX(B.E3) FROM t1 AS B WHERE A.E2 = B.E2)) AS THEMAX ON t1.E1 = THEMAX.E2 AND t1.E1 = t1.E2;
+drop table t1;
+
+create table t1 (a int);
+insert into t1 values (1),(2);
+select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
+explain select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
+drop table t1;
+
+#
+# "Using index" in explain
+#
+create table t2 (a int, b int, primary key (a));
+insert into t2 values (1,7),(2,7);
+explain select a from t2 where a>1;
+explain select a from (select a from t2 where a>1) tt;
+drop table t2;
+
+#
+# prepared EXPLAIN
+#
+create table t1 
+(
+  c1  tinyint, c2  smallint, c3  mediumint, c4  int,
+  c5  integer, c6  bigint, c7  float, c8  double,
+  c9  double precision, c10 real, c11 decimal(7, 4), c12 numeric(8, 4),
+  c13 date, c14 datetime, c15 timestamp, c16 time,
+  c17 year, c18 bit, c19 bool, c20 char,
+  c21 char(10), c22 varchar(30), c23 tinyblob, c24 tinytext,
+  c25 blob, c26 text, c27 mediumblob, c28 mediumtext,
+  c29 longblob, c30 longtext, c31 enum('one', 'two', 'three'),
+  c32 set('monday', 'tuesday', 'wednesday')
+) engine = MYISAM ;
+create table t2 like t1;
+
+set @save_optimizer_switch=@@optimizer_switch;
+set @@optimizer_switch="partial_match_rowid_merge=off,partial_match_table_scan=off";
+
+set @stmt= ' explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25 ' ;
+prepare stmt1 from @stmt ;
+execute stmt1 ;
+execute stmt1 ;
+explain SELECT (SELECT SUM(c1 + c12 + 0.0) FROM t2 where (t1.c2 - 0e-3) = t2.c2 GROUP BY t1.c15 LIMIT 1) as scalar_s, exists (select 1.0e+0 from t2 where t2.c3 * 9.0000000000 = t1.c4) as exists_s, c5 * 4 in (select c6 + 0.3e+1 from t2) as in_s, (c7 - 4, c8 - 4) in (select c9 + 4.0, c10 + 40e-1 from t2) as in_row_s FROM t1, (select c25 x, c32 y from t2) tt WHERE x * 1 = c25;
+deallocate prepare stmt1;
+drop tables t1,t2;
+
+set @@optimizer_switch=@save_optimizer_switch;
+
+--echo #
+--echo #  LP bug #793436: query with a derived table for which optimizer proves
+--echo #                  that it contains not more than 1 row
+--echo #
+
+CREATE TABLE t1 (a int, KEY (a)) ;
+INSERT INTO t1 VALUES (3), (1);
+CREATE TABLE t2 (a int);
+INSERT INTO t2 VALUES (3);
+
+EXPLAIN
+SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
+SELECT * FROM (SELECT DISTINCT * FROM t2) t, t1  WHERE t1.a = t.a;
+
+DROP TABLE t1,t2;
+
+--echo #
+--echo #  LP bug #800518: crash with a query over a derived table
+--echo #                  when a min/max optimization is applied
+--echo #
+
+CREATE TABLE t1 (a int, b int, c varchar(10), INDEX idx(a,b)) ;
+INSERT INTO t1 VALUES 
+  (100, 3, 'xxx'), (200, 7, 'yyyyyyy'), (100, 1, 't'),
+  (200, 4, 'aaaa'), (100, 3, 'eee'), (100, 5, 'zzzzz');
+
+EXPLAIN
+SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
+SELECT MAX(b) FROM (SELECT * FROM t1) AS t WHERE a = 100;
+
+DROP TABLE t1;
+
+--echo #
+--echo #  LP bug #799499: query over a materialized view 
+--echo #                  accessed by a key
+--echo #
+
+CREATE TABLE t1 (a int) ;
+INSERT INTO t1 VALUES (8);
+
+CREATE TABLE t2 (a int, b int) ;
+INSERT INTO t2 VALUES
+  (262, NULL), (253, 190), (260, NULL), (250, 163), (188, 8),
+  (257,200), (256, NULL), (255, 8), (249, NULL), (259, 7);
+
+CREATE VIEW v1 AS SELECT a, MIN(b) AS b FROM t2 GROUP BY a;
+
+EXPLAIN
+SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
+SELECT * FROM v1, t1 WHERE v1.b=t1.a  ORDER BY v1.a;
+
+DROP VIEW v1;
+DROP TABLE t1,t2;
+
+--echo #
+--echo #  LP bug #800085: crash with a query using a simple derived table 
+--echo #                  (fixed by the patch for bug 798621)
+--echo #
+
+CREATE TABLE t1 (f1 int, f2 varchar(32)) ;
+INSERT INTO t1 VALUES (NULL,'j'), (8,'c');
+
+CREATE TABLE t2 (f1 int);
+INSERT INTO t2 VALUES (1), (5);
+
+SELECT DISTINCT t.f1 FROM (SELECT * FROM t1) AS t, t2
+  WHERE t.f2='s' AND t.f2 LIKE '%a%' OR t.f1<>0 ORDER BY t.f2;
+
+DROP TABLE t1, t2;
+
+# The following command must be the last one the file 
+set optimizer_switch=@exit_optimizer_switch;
diff --git a/mysql-test/t/derived_view.test b/mysql-test/t/derived_view.test
index fd51b9b3de2..41cf1444926 100644
--- a/mysql-test/t/derived_view.test
+++ b/mysql-test/t/derived_view.test
@@ -2,6 +2,12 @@
 drop table if exists t1,t2;
 drop view if exists v1,v2,v3,v4;
 --enable_warnings
+
+set @exit_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='derived_merge=on,derived_with_keys=on';
+# The 'default' value within the scope of this test:
+set @save_optimizer_switch=@@optimizer_switch;
+
 create table t1(f1 int, f11 int);
 create table t2(f2 int, f22 int);
 insert into t1 values(1,1),(2,2),(3,3),(5,5),(9,9),(7,7);
@@ -405,7 +411,7 @@ SELECT * FROM t3
 SELECT * FROM t3
   WHERE t3.a IN (SELECT v1.a FROM v1, t2 WHERE t2.a = v1.b);
 
-SET SESSION optimizer_switch=default;
+SET SESSION optimizer_switch=@save_optimizer_switch;
 
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
@@ -454,7 +460,7 @@ EXPLAIN
 SELECT * FROM t1 AS t JOIN v1 AS v WHERE t.a = v.b AND t.b = v.b;
 SELECT * FROM t1 AS t JOIN v1 AS v WHERE t.a = v.b AND t.b = v.b;
 
-SET SESSION optimizer_switch=default;
+SET SESSION optimizer_switch=@save_optimizer_switch;
 
 DROP VIEW v1;
 DROP TABLE t1;
@@ -697,3 +703,28 @@ SELECT a FROM t1 WHERE (a,b) IN (SELECT * FROM v2);
 
 DROP VIEW v1,v2;
 DROP TABLE t1,t2,t3;
+
+--echo #
+--echo # LP bug #804686: query over a derived table using a view 
+--echo #                 with a degenerated where condition
+--echo #
+
+CREATE TABLE t1 (a int, b int);
+INSERT INTO t1 VALUES (0,0), (1,0), (0,0), (1,1), (1,0);
+CREATE VIEW v1 AS SELECT a,b FROM t1;
+CREATE VIEW v2 AS SELECT a, MAX(b) AS b FROM t1 GROUP BY a;
+
+SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b<>0;
+SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b<>0;
+SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
+SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
+EXPLAIN EXTENDED
+SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
+EXPLAIN EXTENDED
+SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
+
+DROP VIEW v1,v2;
+DROP TABLE t1;
+
+# The following command must be the last one the file 
+set optimizer_switch=@exit_optimizer_switch;
diff --git a/mysql-test/t/join_cache.test b/mysql-test/t/join_cache.test
index 873fab045df..925cec81854 100644
--- a/mysql-test/t/join_cache.test
+++ b/mysql-test/t/join_cache.test
@@ -3109,7 +3109,7 @@ DROP TABLE t1,t2;
 --echo #
 
 SET SESSION optimizer_switch=
-  'semijoin=on,materialization=off,firstmatch=off,loosescan=off';
+  'semijoin=on,materialization=off,firstmatch=off,loosescan=off,derived_with_keys=on';
 
 CREATE TABLE t1 (a int) ;
 INSERT IGNORE INTO t1 VALUES (0), (1), (0);
diff --git a/mysql-test/t/view.test b/mysql-test/t/view.test
index 9eafae1729f..5b83c89e7bb 100644
--- a/mysql-test/t/view.test
+++ b/mysql-test/t/view.test
@@ -4193,28 +4193,6 @@ DROP VIEW v1;
 DROP TABLE t1,t2;
 
 --echo #
---echo # LP bug #804686: query over a derived table using a view 
---echo #                 with a degenerated where condition
---echo #
-
-CREATE TABLE t1 (a int, b int);
-INSERT INTO t1 VALUES (0,0), (1,0), (0,0), (1,1), (1,0);
-CREATE VIEW v1 AS SELECT a,b FROM t1;
-CREATE VIEW v2 AS SELECT a, MAX(b) AS b FROM t1 GROUP BY a;
-
-SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b<>0;
-SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b<>0;
-SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
-SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
-EXPLAIN EXTENDED
-SELECT * FROM (SELECT b FROM v1 WHERE b = 0) t WHERE b;
-EXPLAIN EXTENDED
-SELECT * FROM (SELECT b FROM v2 WHERE b = 0) t WHERE b;
-
-DROP VIEW v1,v2;
-DROP TABLE t1;
-
---echo #
 --echo # LP bug #793386: unexpected 'Duplicate column name ''' error
 --echo #                 at the second execution of a PS using a view 
 --echo #
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 68184a94666..98f5d6a727d 100644
--- a/sql/mysql_priv.h
+++ b/sql/mysql_priv.h
@@ -604,8 +604,6 @@ enabled by default, add OPTIMIZER_SWITCH_MATERIALIZATION
                                     OPTIMIZER_SWITCH_INDEX_MERGE_UNION | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION | \
                                     OPTIMIZER_SWITCH_INDEX_MERGE_INTERSECT | \
-                                    OPTIMIZER_SWITCH_DERIVED_MERGE | \
-                                    OPTIMIZER_SWITCH_DERIVED_WITH_KEYS | \
                                     OPTIMIZER_SWITCH_TABLE_ELIMINATION | \
                                     OPTIMIZER_SWITCH_IN_TO_EXISTS | \
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_ROWID_MERGE|\
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index f6cbf581627..2e9089400e5 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -482,8 +482,8 @@ static const char *optimizer_switch_str="index_merge=on,index_merge_union=on,"
                                         "index_merge_intersection=on,"
                                         "index_merge_sort_intersection=off,"
                                         "index_condition_pushdown=on,"
-                                        "derived_merge=on,"
-                                        "derived_with_keys=on,"
+                                        "derived_merge=off,"
+                                        "derived_with_keys=off,"
                                         "firstmatch=off,"
                                         "loosescan=off,"
                                         "materialization=off,"