Fixed bug lp:1000649

Analysis:

When the method JOIN::choose_subquery_plan() decided to apply
the IN-TO-EXISTS strategy, it set the unit and select_lex
uncacheable flag to UNCACHEABLE_DEPENDENT_INJECTED unconditionally.
As result, even if IN-TO-EXISTS injected non-correlated predicates,
the subquery was still treated as correlated.

Solution:
Set the subquery as correlated only if the injected predicate(s) depend
on the outer query.

1 files changed, 5 insertions, 5 deletions

diff --git a/mysql-test/r/subselect_no_mat.result b/mysql-test/r/subselect_no_mat.result
index 7efda485e18..671a5df213b 100644
--- a/mysql-test/r/subselect_no_mat.result
+++ b/mysql-test/r/subselect_no_mat.result
@@ -1327,7 +1327,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 INSERT INTO t1 (pseudo) VALUES ('test1');
@@ -1337,7 +1337,7 @@ SELECT 0 IN (SELECT 1 FROM t1 a);
 EXPLAIN EXTENDED SELECT 0 IN (SELECT 1 FROM t1 a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	No tables used
-2	DEPENDENT SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
+2	SUBQUERY	NULL	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Impossible WHERE noticed after reading const tables
 Warnings:
 Note	1003	select <in_optimizer>(0,<exists>(select 1 from `test`.`t1` `a` where (0 = 1))) AS `0 IN (SELECT 1 FROM t1 a)`
 drop table t1;
@@ -4476,13 +4476,13 @@ SET join_cache_level=0;
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT min(a) FROM t1 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using temporary
 Warnings:
 Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select min(`test`.`t1`.`a`) from `test`.`t1` group by `test`.`t1`.`a` having (1 = <ref_null_helper>(min(`test`.`t1`.`a`))))))
 EXPLAIN EXTENDED SELECT 1 FROM t1 WHERE 1 IN (SELECT min(a) FROM t1 WHERE a > 3 GROUP BY a);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	100.00	Using where; Using temporary
 Warnings:
 Note	1003	select 1 AS `1` from `test`.`t1` where <expr_cache><1>(<in_optimizer>(1,<exists>(select min(`test`.`t1`.`a`) from `test`.`t1` where (`test`.`t1`.`a` > 3) group by `test`.`t1`.`a` having (1 = <ref_null_helper>(min(`test`.`t1`.`a`))))))
 SET join_cache_level=@save_join_cache_level;
@@ -5318,7 +5318,7 @@ WHERE ('0') IN ( SELECT a  FROM t1 GROUP BY a )
 GROUP BY b;
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
 1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using temporary; Using filesort
-2	DEPENDENT SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
+2	SUBQUERY	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
 SELECT b FROM t1
 WHERE ('0') IN ( SELECT a  FROM t1 GROUP BY a )
 GROUP BY b;