Fixed LP bug #889750.

If the optimizer switch 'semijoin_with_cache' is set to 'off' then 
join cache cannot be used to join inner tables of a semijoin.

Also fixed a bug in the function check_join_cache_usage() that led
to wrong output of the EXPLAIN commands for some test cases.

1 files changed, 4 insertions, 4 deletions

diff --git a/mysql-test/r/subselect3.result b/mysql-test/r/subselect3.result
index 1279fc6b8f4..9ce3c8dfbe3 100644
--- a/mysql-test/r/subselect3.result
+++ b/mysql-test/r/subselect3.result
@@ -1,6 +1,6 @@
 drop table if exists t0, t1, t2, t3, t4, t5, t11, t12, t21, t22;
 set @subselect3_tmp= @@optimizer_switch;
-set optimizer_switch='semijoin=on,firstmatch=on,loosescan=on';
+set optimizer_switch='semijoin=on,firstmatch=on,loosescan=on,semijoin_with_cache=on';
 create table t1 (oref int, grp int, ie int) ;
 insert into t1 (oref, grp, ie) values
 (1, 1, 1),
@@ -345,8 +345,8 @@ dd	NULL	0
 bb	NULL	NULL
 select oref, a from t2 where a in (select ie from t1 where oref=t2.oref);
 oref	a
-ff	2
 aa	1
+ff	2
 select oref, a from t2 where a not in (select ie from t1 where oref=t2.oref);
 oref	a
 bb	2
@@ -523,8 +523,8 @@ aa	1	1	1
 dd	1	NULL	0
 select oref, a, b from t2 where (a,b) in (select ie1,ie2 from t1 where oref=t2.oref);
 oref	a	b
-ff	2	2
 aa	1	1
+ff	2	2
 select oref, a, b from t2 where (a,b) not in (select ie1,ie2 from t1 where oref=t2.oref);
 oref	a	b
 bb	2	1
@@ -1117,7 +1117,7 @@ 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	<derived2>	ALL	NULL	NULL	NULL	NULL	11	
-1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	20	Using where; FirstMatch(<derived2>)
+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);