database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

Fixed LP bug #899696.

Browse Source 
If has been decided that the first match strategy is to be used to join table T
from a semi-join nest while no buffer can be employed to join this table
then no join buffer can be used to join any table in the join sequence between
the first one belonging to the semi-join nest and table T.
This commit is contained in:
Igor Babaev
2011-12-04 07:43:33 -08:00
parent 921004e79d
commit b5a05df61e
3 changed files with 56 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
mysql-test/r/subselect_sj2_jcl6.result
View File

@ -928,6 +928,33 @@ x x
set optimizer_switch=@tmp_optimizer_switch;
set join_cache_level=default;
DROP TABLE t1,t2,t3,t4;
#
# Bug #899696: potential incremental join cache for semijoin
#
CREATE TABLE t1 (pk int PRIMARY KEY, a int);
INSERT INTO t1 VALUES (1, 6), (2, 8);
CREATE TABLE t2 (b int) ENGINE=InnoDB;
INSERT INTO t2 VALUES (8);
CREATE TABLE t3 (pk int PRIMARY KEY, a int);
INSERT INTO t3 VALUES (1, 6), (2, 8);
CREATE TABLE t4 (b int) ENGINE=InnoDB;
INSERT INTO t4 VALUES (2);
set @tmp_optimizer_switch=@@optimizer_switch;
SET optimizer_switch = 'semijoin_with_cache=on';
SET join_cache_level = 2;
EXPLAIN
SELECT * FROM t1, t2 WHERE b IN (SELECT a FROM t3, t4 WHERE b = pk);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 1
1 PRIMARY t4 ALL NULL NULL NULL NULL 1 Using where
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
1 PRIMARY t3 eq_ref PRIMARY PRIMARY 4 test.t4.b 1 Using where; FirstMatch(t4)
SELECT * FROM t1, t2 WHERE b IN (SELECT a FROM t3, t4 WHERE b = pk);
pk a b
1 6 8
set optimizer_switch=@tmp_optimizer_switch;
set join_cache_level=default;
DROP TABLE t1,t2,t3,t4;
set join_cache_level=default;
show variables like 'join_cache_level';
Variable_name Value

28
mysql-test/t/subselect_sj2_jcl6.test
View File

@ -45,6 +45,34 @@ set join_cache_level=default;
DROP TABLE t1,t2,t3,t4;
--echo #
--echo # Bug #899696: potential incremental join cache for semijoin
--echo #
CREATE TABLE t1 (pk int PRIMARY KEY, a int);
INSERT INTO t1 VALUES (1, 6), (2, 8);
CREATE TABLE t2 (b int) ENGINE=InnoDB;
INSERT INTO t2 VALUES (8);
CREATE TABLE t3 (pk int PRIMARY KEY, a int);
INSERT INTO t3 VALUES (1, 6), (2, 8);
CREATE TABLE t4 (b int) ENGINE=InnoDB;
INSERT INTO t4 VALUES (2);
set @tmp_optimizer_switch=@@optimizer_switch;
SET optimizer_switch = 'semijoin_with_cache=on';
SET join_cache_level = 2;
EXPLAIN
SELECT * FROM t1, t2 WHERE b IN (SELECT a FROM t3, t4 WHERE b = pk);
SELECT * FROM t1, t2 WHERE b IN (SELECT a FROM t3, t4 WHERE b = pk);
set optimizer_switch=@tmp_optimizer_switch;
set join_cache_level=default;
DROP TABLE t1,t2,t3,t4;
set join_cache_level=default;
show variables like 'join_cache_level';

3
sql/sql_select.cc
View File

@ -8767,8 +8767,7 @@ void revise_cache_usage(JOIN_TAB *join_tab)
first_inner= join_tab->first_sj_inner_tab;
for (tab= join_tab-1; tab >= first_inner; tab--)
{
if (tab->first_sj_inner_tab == first_inner)
set_join_cache_denial(tab);
set_join_cache_denial(tab);
}
}
else set_join_cache_denial(join_tab);