Making subquery cache on by default.

mysql-test/r/compare.result

@@ -88,7 +88,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 Warnings:
 Note	1276	Field or reference 'test.t2.a' of SELECT #2 was resolved in SELECT #1
 Note	1276	Field or reference 'test.t2.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`a` AS `a`,(select count(0) from `test`.`t1` where ((`test`.`t1`.`b` = `test`.`t2`.`a`) and (concat(`test`.`t1`.`b`,`test`.`t1`.`c`) = concat('0',`test`.`t2`.`a`,'01')))) AS `x` from `test`.`t2` order by `test`.`t2`.`a`
+Note	1003	select `test`.`t2`.`a` AS `a`,<expr_cache><`test`.`t2`.`a`>((select count(0) from `test`.`t1` where ((`test`.`t1`.`b` = `test`.`t2`.`a`) and (concat(`test`.`t1`.`b`,`test`.`t1`.`c`) = concat('0',`test`.`t2`.`a`,'01'))))) AS `x` from `test`.`t2` order by `test`.`t2`.`a`
 DROP TABLE t1,t2;
 CREATE TABLE t1 (a TIMESTAMP);
 INSERT INTO t1 VALUES (NOW()),(NOW()),(NOW());

mysql-test/r/derived_view.result

@@ -785,7 +785,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	3	100.00	Using where; Using join buffer (flat, BNL join)
 3	DERIVED	t1	ALL	NULL	NULL	NULL	NULL	3	100.00	Using temporary; Using filesort
 Warnings:
-Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <in_optimizer>(`test`.`t3`.`a`,<exists>(select `v1`.`a` from `test`.`v1` join `test`.`t2` where ((`test`.`t2`.`a` = `v1`.`b`) and (<cache>(`test`.`t3`.`a`) = `v1`.`a`))))
+Note	1003	select `test`.`t3`.`a` AS `a` from `test`.`t3` where <expr_cache><`test`.`t3`.`a`>(<in_optimizer>(`test`.`t3`.`a`,<exists>(select `v1`.`a` from `test`.`v1` join `test`.`t2` where ((`test`.`t2`.`a` = `v1`.`b`) and (<cache>(`test`.`t3`.`a`) = `v1`.`a`)))))
 SELECT * FROM t3
 WHERE t3.a IN (SELECT v1.a FROM v1, t2 WHERE t2.a = v1.b);
 a
@@ -992,7 +992,7 @@ 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
 3	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0)))
+Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0))))
 SELECT * FROM t2 RIGHT JOIN v1 AS t ON t.a != 0
 WHERE t.a IN (SELECT b FROM t1);
 a	a	b
@@ -1005,7 +1005,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 2	DEPENDENT SUBQUERY	t1	system	NULL	NULL	NULL	NULL	1	100.00	
 Warnings:
-Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0)))
+Note	1003	select `test`.`t2`.`a` AS `a`,0 AS `a`,0 AS `b` from `test`.`t1` left join `test`.`t2` on((0 <> 0)) where <expr_cache><0>(<in_optimizer>(0,<exists>(select 0 from `test`.`t1` where (<cache>(0) = 0))))
 DROP VIEW v1;
 DROP TABLE t1,t2;
 #
@@ -1079,7 +1079,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	system	NULL	NULL	NULL	NULL	1	100.00	
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select 6 AS `a`,5 AS `b` from `test`.`t1` `t` join `test`.`t2` left join `test`.`t3` on((0 <> 0)) where (not(<in_optimizer>((6,5),<exists>(select 7,5 having (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5) or isnull(5))) and trigcond(<is_not_null_test>(7)) and trigcond(<is_not_null_test>(5)))))))
+Note	1003	select 6 AS `a`,5 AS `b` from `test`.`t1` `t` join `test`.`t2` left join `test`.`t3` on((0 <> 0)) where (not(<expr_cache><6,5>(<in_optimizer>((6,5),<exists>(select 7,5 having (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5) or isnull(5))) and trigcond(<is_not_null_test>(7)) and trigcond(<is_not_null_test>(5))))))))
 SELECT t.a,t.b FROM t3 RIGHT JOIN ((SELECT * FROM t1) AS t, t2) ON t2.b != 0 
 WHERE (t.a,t.b) NOT IN (SELECT 7, 5);
 a	b
@@ -1093,7 +1093,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	system	NULL	NULL	NULL	NULL	1	100.00	
 3	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select 6 AS `a`,5 AS `b` from `test`.`t1` join `test`.`t2` left join `test`.`t3` on((0 <> 0)) where (not(<in_optimizer>((6,5),<exists>(select 7,5 having (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5) or isnull(5))) and trigcond(<is_not_null_test>(7)) and trigcond(<is_not_null_test>(5)))))))
+Note	1003	select 6 AS `a`,5 AS `b` from `test`.`t1` join `test`.`t2` left join `test`.`t3` on((0 <> 0)) where (not(<expr_cache><6,5>(<in_optimizer>((6,5),<exists>(select 7,5 having (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5) or isnull(5))) and trigcond(<is_not_null_test>(7)) and trigcond(<is_not_null_test>(5))))))))
 SELECT t.a,t.b FROM t3 RIGHT JOIN (v1 AS t, t2) ON t2.b != 0 
 WHERE (t.a,t.b) NOT IN (SELECT 7, 5);
 a	b
@@ -1107,7 +1107,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t3	system	NULL	NULL	NULL	NULL	1	100.00	
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
-Note	1003	select 6 AS `a`,5 AS `b` from `test`.`t1` join `test`.`t2` left join `test`.`t3` on((0 <> 0)) where (not(<in_optimizer>((6,5),<exists>(select 7,5 having (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5) or isnull(5))) and trigcond(<is_not_null_test>(7)) and trigcond(<is_not_null_test>(5)))))))
+Note	1003	select 6 AS `a`,5 AS `b` from `test`.`t1` join `test`.`t2` left join `test`.`t3` on((0 <> 0)) where (not(<expr_cache><6,5>(<in_optimizer>((6,5),<exists>(select 7,5 having (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5) or isnull(5))) and trigcond(<is_not_null_test>(7)) and trigcond(<is_not_null_test>(5))))))))
 DROP VIEW v1;
 DROP TABLE t1,t2,t3;
 #
@@ -1266,7 +1266,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
 Note	1276	Field or reference 't.a' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where exists(select 28 from `test`.`t2` left join `test`.`t3` on((`test`.`t3`.`a` = 28)) where ('j' < `test`.`t1`.`a`))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` where <expr_cache><`test`.`t1`.`a`>(exists(select 28 from `test`.`t2` left join `test`.`t3` on((`test`.`t3`.`a` = 28)) where ('j' < `test`.`t1`.`a`)))
 SELECT * FROM (SELECT * FROM t1) AS t
 WHERE EXISTS (SELECT t2.a FROM t3 RIGHT JOIN t2 ON (t3.a = t2.a)
 WHERE t2.b < t.a);

mysql-test/r/explain.result

@@ -228,7 +228,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
-Note	1003	select (select 1 from `test`.`t2` where (`test`.`t2`.`d` = NULL)) AS `(SELECT 1 FROM t2 WHERE d = c)` from `test`.`t1`
+Note	1003	select <expr_cache><NULL>((select 1 from `test`.`t2` where (`test`.`t2`.`d` = NULL))) AS `(SELECT 1 FROM t2 WHERE d = c)` from `test`.`t1`
 DROP TABLE t1, t2;
 #
 # Bug #48419: another explain crash..

mysql-test/r/group_by.result

@@ -1742,7 +1742,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1276	Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select (select `test`.`t1`.`a`) AS `aa`,count(distinct `test`.`t1`.`b`) AS `COUNT(DISTINCT b)` from `test`.`t1` group by ((select `test`.`t1`.`a`) + 0)
+Note	1003	select <expr_cache><`test`.`t1`.`a`>((select `test`.`t1`.`a`)) AS `aa`,count(distinct `test`.`t1`.`b`) AS `COUNT(DISTINCT b)` from `test`.`t1` group by (<expr_cache><`test`.`t1`.`a`>((select `test`.`t1`.`a`)) + 0)
 EXPLAIN EXTENDED
 SELECT (SELECT t1.a) aa, COUNT(DISTINCT b) FROM t1 GROUP BY -aa;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
@@ -1750,7 +1750,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
 Warnings:
 Note	1276	Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select (select `test`.`t1`.`a`) AS `aa`,count(distinct `test`.`t1`.`b`) AS `COUNT(DISTINCT b)` from `test`.`t1` group by -((select `test`.`t1`.`a`))
+Note	1003	select <expr_cache><`test`.`t1`.`a`>((select `test`.`t1`.`a`)) AS `aa`,count(distinct `test`.`t1`.`b`) AS `COUNT(DISTINCT b)` from `test`.`t1` group by -(<expr_cache><`test`.`t1`.`a`>((select `test`.`t1`.`a`)))
 # should return only one record
 SELECT (SELECT tt.a FROM t1 tt LIMIT 1) aa, COUNT(DISTINCT b) FROM t1
 GROUP BY aa;

mysql-test/r/join_outer.result

@@ -1438,7 +1438,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t3.pk	1	100.00	Using where; Using index
 Warnings:
 Note	1276	Field or reference 'test.t2.pk' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`pk` AS `pk`,(select (`test`.`t3`.`pk` + if(isnull(`test`.`t4`.`pk`),0,`test`.`t4`.`pk`)) from `test`.`t3` left join `test`.`t4` on((`test`.`t4`.`pk` = `test`.`t3`.`pk`)) where (`test`.`t3`.`pk` = (`test`.`t2`.`pk` + 1000)) limit 1) AS `t` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`pk` = (`test`.`t1`.`pk` + 1000)) and (`test`.`t1`.`pk` > 1000)) group by `test`.`t2`.`pk`
+Note	1003	select `test`.`t2`.`pk` AS `pk`,<expr_cache><`test`.`t2`.`pk`>((select (`test`.`t3`.`pk` + if(isnull(`test`.`t4`.`pk`),0,`test`.`t4`.`pk`)) from `test`.`t3` left join `test`.`t4` on((`test`.`t4`.`pk` = `test`.`t3`.`pk`)) where (`test`.`t3`.`pk` = (`test`.`t2`.`pk` + 1000)) limit 1)) AS `t` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`pk` = (`test`.`t1`.`pk` + 1000)) and (`test`.`t1`.`pk` > 1000)) group by `test`.`t2`.`pk`
 select t2.pk, 
 (select t3.pk+if(isnull(t4.pk),0,t4.pk)
 from t3 left join t4 on t4.pk=t3.pk 

mysql-test/r/join_outer_jcl6.result

@@ -1447,7 +1447,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t4	eq_ref	PRIMARY	PRIMARY	4	test.t3.pk	1	100.00	Using where; Using index
 Warnings:
 Note	1276	Field or reference 'test.t2.pk' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`pk` AS `pk`,(select (`test`.`t3`.`pk` + if(isnull(`test`.`t4`.`pk`),0,`test`.`t4`.`pk`)) from `test`.`t3` left join `test`.`t4` on((`test`.`t4`.`pk` = `test`.`t3`.`pk`)) where (`test`.`t3`.`pk` = (`test`.`t2`.`pk` + 1000)) limit 1) AS `t` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`pk` = (`test`.`t1`.`pk` + 1000)) and (`test`.`t1`.`pk` > 1000)) group by `test`.`t2`.`pk`
+Note	1003	select `test`.`t2`.`pk` AS `pk`,<expr_cache><`test`.`t2`.`pk`>((select (`test`.`t3`.`pk` + if(isnull(`test`.`t4`.`pk`),0,`test`.`t4`.`pk`)) from `test`.`t3` left join `test`.`t4` on((`test`.`t4`.`pk` = `test`.`t3`.`pk`)) where (`test`.`t3`.`pk` = (`test`.`t2`.`pk` + 1000)) limit 1)) AS `t` from `test`.`t1` join `test`.`t2` where ((`test`.`t2`.`pk` = (`test`.`t1`.`pk` + 1000)) and (`test`.`t1`.`pk` > 1000)) group by `test`.`t2`.`pk`
 select t2.pk, 
 (select t3.pk+if(isnull(t4.pk),0,t4.pk)
 from t3 left join t4 on t4.pk=t3.pk 

mysql-test/r/subselect4.result

@@ -224,7 +224,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1276	Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
-Note	1003	select (select 1 from `test`.`t2` where 0) AS `RESULT` from `test`.`t1`
+Note	1003	select <expr_cache><>((select 1 from `test`.`t2` where 0)) AS `RESULT` from `test`.`t1`
 first equivalent variant
 SELECT (SELECT 1 FROM t2 WHERE d = IFNULL(c,NULL)) AS RESULT FROM t1 GROUP BY c ;
 RESULT
@@ -235,7 +235,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1276	Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
-Note	1003	select (select 1 from `test`.`t2` where 0) AS `RESULT` from `test`.`t1` group by NULL
+Note	1003	select <expr_cache><>((select 1 from `test`.`t2` where 0)) AS `RESULT` from `test`.`t1` group by NULL
 second equivalent variant
 SELECT (SELECT 1 FROM t2 WHERE d = c) AS RESULT FROM t1 GROUP BY c ;
 RESULT
@@ -246,7 +246,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1276	Field or reference 'test.t1.c' of SELECT #2 was resolved in SELECT #1
-Note	1003	select (select 1 from `test`.`t2` where 0) AS `RESULT` from `test`.`t1` group by NULL
+Note	1003	select <expr_cache><>((select 1 from `test`.`t2` where 0)) AS `RESULT` from `test`.`t1` group by NULL
 DROP TABLE t1,t2;
 #
 # BUG#45928 "Differing query results depending on MRR and

mysql-test/r/subselect_mat_cost_bugs.result

@@ -100,7 +100,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t2	index	c3	c3	9	NULL	2	100.00	Using where; Using index; Using join buffer (flat, BNL join)
 Warnings:
 Note	1276	Field or reference 'test.t1.pk' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on((2 and (`test`.`t1a`.`c2` = `test`.`t1b`.`pk`))) where ((`test`.`t1`.`pk` <> 0) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`) and (`test`.`t2`.`c3` = `test`.`t1b`.`c4`))))
+Note	1003	select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <expr_cache><`test`.`t1`.`c1`,`test`.`t1`.`pk`>(<in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on((2 and (`test`.`t1a`.`c2` = `test`.`t1b`.`pk`))) where ((`test`.`t1`.`pk` <> 0) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`) and (`test`.`t2`.`c3` = `test`.`t1b`.`c4`)))))
 SELECT pk
 FROM t1
 WHERE c1 IN

mysql-test/r/subselect_no_opts.result

-set @optimizer_switch_for_subselect_test='materialization=off,semijoin=off,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
+set @optimizer_switch_for_subselect_test='materialization=off,semijoin=off,subquery_cache=off,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
 drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t11,t12;
 drop view if exists v2;
 set @subselect_tmp=@@optimizer_switch;

mysql-test/r/subselect_sj.result

@@ -761,11 +761,11 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 show warnings;
 Level	Code	Message
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 select a from t1
 where a in (select c from t2 where d >= some(select e from t3 where b=e));
 a

mysql-test/r/subselect_sj_jcl6.result

@@ -772,11 +772,11 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 3	DEPENDENT SUBQUERY	t3	ALL	NULL	NULL	NULL	NULL	4	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 show warnings;
 Level	Code	Message
 Note	1276	Field or reference 'test.t1.b' of SELECT #3 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`))))))
+Note	1003	select `test`.`t1`.`a` AS `a` from `test`.`t1` semi join (`test`.`t2`) where ((`test`.`t1`.`a` = `test`.`t2`.`c`) and <nop>(<expr_cache><`test`.`t2`.`d`,`test`.`t1`.`b`>(<in_optimizer>(`test`.`t2`.`d`,<exists>(select `test`.`t3`.`e` from `test`.`t3` where ((`test`.`t1`.`b` = `test`.`t3`.`e`) and (<cache>(`test`.`t2`.`d`) >= `test`.`t3`.`e`)))))))
 select a from t1
 where a in (select c from t2 where d >= some(select e from t3 where b=e));
 a

mysql-test/r/type_datetime.result

@@ -518,7 +518,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 Warnings:
 Note	1276	Field or reference 'test.t1.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select 1 AS `id`,'2007-04-25 18:30:22' AS `cur_date` from `test`.`t1` where <in_optimizer>(1,<exists>(select `test`.`x1`.`id` from `test`.`t1` `x1` where 0))
+Note	1003	select 1 AS `id`,'2007-04-25 18:30:22' AS `cur_date` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select `test`.`x1`.`id` from `test`.`t1` `x1` where 0)))
 select * from t1
 where id in (select id from t1 as x1 where (t1.cur_date is null));
 id	cur_date
@@ -530,7 +530,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE
 Warnings:
 Note	1276	Field or reference 'test.t2.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select 1 AS `id`,'2007-04-25' AS `cur_date` from `test`.`t2` where <in_optimizer>(1,<exists>(select `test`.`x1`.`id` from `test`.`t2` `x1` where 0))
+Note	1003	select 1 AS `id`,'2007-04-25' AS `cur_date` from `test`.`t2` where <expr_cache><1>(<in_optimizer>(1,<exists>(select `test`.`x1`.`id` from `test`.`t2` `x1` where 0)))
 select * from t2
 where id in (select id from t2 as x1 where (t2.cur_date is null));
 id	cur_date
@@ -544,7 +544,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	x1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`id` AS `id`,`test`.`t1`.`cur_date` AS `cur_date` from `test`.`t1` where <in_optimizer>(`test`.`t1`.`id`,<exists>(select `test`.`x1`.`id` from `test`.`t1` `x1` where ((`test`.`t1`.`cur_date` = 0) and (<cache>(`test`.`t1`.`id`) = `test`.`x1`.`id`))))
+Note	1003	select `test`.`t1`.`id` AS `id`,`test`.`t1`.`cur_date` AS `cur_date` from `test`.`t1` where <expr_cache><`test`.`t1`.`id`,`test`.`t1`.`cur_date`>(<in_optimizer>(`test`.`t1`.`id`,<exists>(select `test`.`x1`.`id` from `test`.`t1` `x1` where ((`test`.`t1`.`cur_date` = 0) and (<cache>(`test`.`t1`.`id`) = `test`.`x1`.`id`)))))
 select * from t1
 where id in (select id from t1 as x1 where (t1.cur_date is null));
 id	cur_date
@@ -556,7 +556,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	x1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t2.cur_date' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t2`.`id` AS `id`,`test`.`t2`.`cur_date` AS `cur_date` from `test`.`t2` where <in_optimizer>(`test`.`t2`.`id`,<exists>(select `test`.`x1`.`id` from `test`.`t2` `x1` where ((`test`.`t2`.`cur_date` = 0) and (<cache>(`test`.`t2`.`id`) = `test`.`x1`.`id`))))
+Note	1003	select `test`.`t2`.`id` AS `id`,`test`.`t2`.`cur_date` AS `cur_date` from `test`.`t2` where <expr_cache><`test`.`t2`.`id`,`test`.`t2`.`cur_date`>(<in_optimizer>(`test`.`t2`.`id`,<exists>(select `test`.`x1`.`id` from `test`.`t2` `x1` where ((`test`.`t2`.`cur_date` = 0) and (<cache>(`test`.`t2`.`id`) = `test`.`x1`.`id`)))))
 select * from t2
 where id in (select id from t2 as x1 where (t2.cur_date is null));
 id	cur_date

mysql-test/r/view.result

@@ -4329,7 +4329,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'test.t1.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` join `test`.`t2` where (not(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` left join `test`.`t3` on(multiple equal(NULL, `test`.`t4`.`a`)) where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or isnull(NULL)))) having trigcond(<is_not_null_test>(NULL))))))
+Note	1003	select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` join `test`.`t2` where (not(<expr_cache><10,`test`.`t1`.`a`>(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` left join `test`.`t3` on(multiple equal(NULL, `test`.`t4`.`a`)) where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or isnull(NULL)))) having trigcond(<is_not_null_test>(NULL)))))))
 SELECT * FROM t1, t2
 WHERE t2.a NOT IN (SELECT t3.b FROM t3 RIGHT JOIN t4 ON (t4.a = t3.a)
 WHERE t4.a >= t1.a);
@@ -4345,7 +4345,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 2	DEPENDENT SUBQUERY	t4	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where
 Warnings:
 Note	1276	Field or reference 'v1.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` join `test`.`t2` where (not(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` left join `test`.`t3` on(multiple equal(NULL, `test`.`t4`.`a`)) where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or isnull(NULL)))) having trigcond(<is_not_null_test>(NULL))))))
+Note	1003	select `test`.`t1`.`a` AS `a`,10 AS `a` from `test`.`t1` join `test`.`t2` where (not(<expr_cache><10,`test`.`t1`.`a`>(<in_optimizer>(10,<exists>(select NULL from `test`.`t4` left join `test`.`t3` on(multiple equal(NULL, `test`.`t4`.`a`)) where ((`test`.`t4`.`a` >= `test`.`t1`.`a`) and trigcond(((<cache>(10) = NULL) or isnull(NULL)))) having trigcond(<is_not_null_test>(NULL)))))))
 SELECT * FROM v1, t2
 WHERE t2.a NOT IN (SELECT t3.b FROM t3 RIGHT JOIN t4 ON (t4.a = t3.a)
 WHERE t4.a >= v1.a);

mysql-test/t/subselect_no_opts.test

@@ -3,7 +3,7 @@
 #  (test in-to-exists)
 
 
-set @optimizer_switch_for_subselect_test='materialization=off,semijoin=off,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on'; 
+set @optimizer_switch_for_subselect_test='materialization=off,semijoin=off,subquery_cache=off,mrr=on,mrr_sort_keys=on,index_condition_pushdown=on'; 
 --source t/subselect.test
 
 set @optimizer_switch_for_subselect_test=null; 

mysql-test/t/subselect_scache.test → mysql-test/t/subselect_no_scache.test

@@ -2,7 +2,7 @@
 # Run subselect.test without semi-join optimization (test materialize)
 #
 select @@optimizer_switch like '%subquery_cache=on%';
-set optimizer_switch='subquery_cache=on';
+set optimizer_switch='subquery_cache=off';
 
 --source t/subselect.test
 

sql/mysql_priv.h

@@ -608,7 +608,8 @@ enabled by default, add OPTIMIZER_SWITCH_MATERIALIZATION
                                     OPTIMIZER_SWITCH_PARTIAL_MATCH_TABLE_SCAN|\
                                     OPTIMIZER_SWITCH_JOIN_CACHE_INCREMENTAL | \
                                     OPTIMIZER_SWITCH_JOIN_CACHE_HASHED | \
-                                    OPTIMIZER_SWITCH_JOIN_CACHE_BKA)
+                                    OPTIMIZER_SWITCH_JOIN_CACHE_BKA | \
+                                    OPTIMIZER_SWITCH_SUBQUERY_CACHE)
 
 /*
   Replication uses 8 bytes to store SQL_MODE in the binary log. The day you

sql/mysqld.cc

@@ -491,7 +491,7 @@ static const char *optimizer_switch_str="index_merge=on,index_merge_union=on,"
                                         "semijoin=off,"
                                         "partial_match_rowid_merge=on,"
                                         "partial_match_table_scan=on,"
-                                        "subquery_cache=off,"
+                                        "subquery_cache=on,"
                                         "mrr=off,"
                                         "mrr_cost_based=off,"
                                         "mrr_sort_keys=off,"