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, 1 deletions

diff --git a/mysql-test/r/subselect_no_semijoin.result b/mysql-test/r/subselect_no_semijoin.result
index 7f9e3185d2e..bb1ffa6942a 100644
--- a/mysql-test/r/subselect_no_semijoin.result
+++ b/mysql-test/r/subselect_no_semijoin.result
@@ -3,7 +3,7 @@ drop table if exists t1,t2,t3,t4,t5,t6,t7,t8,t11,t12;
 drop view if exists v2;
 set @subselect_tmp=@@optimizer_switch;
 set @@optimizer_switch=ifnull(@optimizer_switch_for_subselect_test,
-"semijoin=on,firstmatch=on,loosescan=on,partial_match_rowid_merge=off,partial_match_table_scan=off");
+"semijoin=on,firstmatch=on,loosescan=on,semijoin_with_cache=on,partial_match_rowid_merge=off,partial_match_table_scan=off");
 set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
 select (select 2);
 (select 2)
@@ -2894,6 +2894,8 @@ select * from (select max(fld) from t1) as foo;
 max(fld)
 1
 drop table t1;
+set @tmp11867_optimizer_switch=@@optimizer_switch;
+set optimizer_switch='semijoin_with_cache=off';
 CREATE TABLE t1 (one int, two int, flag char(1));
 CREATE TABLE t2 (one int, two int, flag char(1));
 INSERT INTO t1 VALUES(1,2,'Y'),(2,3,'Y'),(3,4,'Y'),(5,6,'N'),(7,8,'N');
@@ -2978,6 +2980,7 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 Warnings:
 Note	1003	select `test`.`t1`.`one` AS `one`,`test`.`t1`.`two` AS `two`,<expr_cache><`test`.`t1`.`one`,`test`.`t1`.`two`>(<in_optimizer>((`test`.`t1`.`one`,`test`.`t1`.`two`),<exists>(select `test`.`t2`.`one`,`test`.`t2`.`two` from `test`.`t2` where (`test`.`t2`.`flag` = '0') group by `test`.`t2`.`one`,`test`.`t2`.`two` having (trigcond(((<cache>(`test`.`t1`.`one`) = `test`.`t2`.`one`) or isnull(`test`.`t2`.`one`))) and trigcond(((<cache>(`test`.`t1`.`two`) = `test`.`t2`.`two`) or isnull(`test`.`t2`.`two`))) and trigcond(<is_not_null_test>(`test`.`t2`.`one`)) and trigcond(<is_not_null_test>(`test`.`t2`.`two`)))))) AS `test` from `test`.`t1`
 DROP TABLE t1,t2;
+set optimizer_switch=@tmp11867_optimizer_switch;
 CREATE TABLE t1 (a char(5), b char(5));
 INSERT INTO t1 VALUES (NULL,'aaa'), ('aaa','aaa');
 SELECT * FROM t1 WHERE (a,b) IN (('aaa','aaa'), ('aaa','bbb'));