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5.3 merge

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This commit is contained in:
Sergei Golubchik
2014-09-12 16:51:41 +02:00
parent 32360bb728 5023bb899d
commit c799d65baf
11 changed files with 560 additions and 11 deletions
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88
mysql-test/r/derived_view.result
View File

@ -2406,6 +2406,94 @@ deallocate prepare stmt;
drop table t1,t2;
set optimizer_switch=@save_optimizer_switch5740;
#
# Bug mdev-5721: possible long key access to a materialized derived table
# (see also the test case for Bug#13261277 that is actually the same bug)
#
CREATE TABLE t1 (
id varchar(255) NOT NULL DEFAULT '',
familyid int(11) DEFAULT NULL,
withdrawndate date DEFAULT NULL,
KEY index_td_familyid_id (familyid,id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE t2 (
id int(11) NOT NULL AUTO_INCREMENT,
activefromts datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
shortdescription text,
useraccessfamily varchar(512) DEFAULT NULL,
serialized longtext,
PRIMARY KEY (id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
insert into t1 values ('picture/89/1369722032695.pmd',89,NULL);
insert into t1 values ('picture/90/1369832057370.pmd',90,NULL);
insert into t2 values (38,'2013-03-04 07:49:22','desc','CODE','string');
EXPLAIN
SELECT * FROM t2 x,
(SELECT t2.useraccessfamily, t2.serialized AS picturesubuser, COUNT(*)
FROM t2, t1 GROUP BY t2.useraccessfamily, picturesubuser) y
WHERE x.useraccessfamily = y.useraccessfamily;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY x system NULL NULL NULL NULL 1
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 Using where
2 DERIVED t2 system NULL NULL NULL NULL 1
2 DERIVED t1 index NULL index_td_familyid_id 772 NULL 2 Using index
SELECT * FROM t2 x,
(SELECT t2.useraccessfamily, t2.serialized AS picturesubuser, COUNT(*)
FROM t2, t1 GROUP BY t2.useraccessfamily, picturesubuser) y
WHERE x.useraccessfamily = y.useraccessfamily;
id activefromts shortdescription useraccessfamily serialized useraccessfamily picturesubuser COUNT(*)
38 2013-03-04 07:49:22 desc CODE string CODE string 2
DROP TABLE t1,t2;
#
# Bug#13261277: Unchecked key length caused missing records.
#
CREATE TABLE t1 (
col_varchar varchar(1024) CHARACTER SET utf8 DEFAULT NULL,
stub1 varchar(1024) CHARACTER SET utf8 DEFAULT NULL,
stub2 varchar(1024) CHARACTER SET utf8 DEFAULT NULL,
stub3 varchar(1024) CHARACTER SET utf8 DEFAULT NULL
);
INSERT INTO t1 VALUES
('d','d','l','ther'),
(NULL,'s','NJBIQ','trzetuchv'),
(-715390976,'coul','MYWFB','cfhtrzetu'),
(1696792576,'f','i\'s','c'),
(1,'i','ltpemcfhtr','gsltpemcf'),
(-663027712,'mgsltpemcf','sa','amgsltpem'),
(-1686700032,'JPRVK','i','vamgsltpe'),
(NULL,'STUNB','UNVJV','u'),
(5,'oka','qyihvamgsl','AXSMD'),
(NULL,'tqwmqyihva','h','yntqwmqyi'),
(3,'EGMJN','e','e');
CREATE TABLE t2 (
col_varchar varchar(10) DEFAULT NULL,
col_int INT DEFAULT NULL
);
INSERT INTO t2 VALUES ('d',9);
set optimizer_switch='derived_merge=off,derived_with_keys=on';
SET @save_heap_size= @@max_heap_table_size;
SET @@max_heap_table_size= 16384;
SELECT t2.col_int
FROM t2
RIGHT JOIN ( SELECT * FROM t1 ) AS dt
ON t2.col_varchar = dt.col_varchar
WHERE t2.col_int IS NOT NULL ;
col_int
9
# Shouldn't use auto_key0 for derived table
EXPLAIN
SELECT t2.col_int
FROM t2
RIGHT JOIN ( SELECT * FROM t1 ) AS dt
ON t2.col_varchar = dt.col_varchar
WHERE t2.col_int IS NOT NULL ;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 system NULL NULL NULL NULL 1
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 11 Using where
2 DERIVED t1 ALL NULL NULL NULL NULL 11
SET @@max_heap_table_size= @save_heap_size;
SET optimizer_switch=@save_optimizer_switch;
DROP TABLE t1,t2;
#
# end of 5.3 tests
#
set optimizer_switch=@exit_optimizer_switch;

149
mysql-test/r/join_cache.result
View File

@ -5656,4 +5656,153 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 10
1 SIMPLE t2 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
drop table t0,t1,t2;
#
# mdev-6292: huge performance degradation for a sequence
# of LEFT JOIN operations when using join buffer
#
CREATE TABLE t1 (
id int(11) NOT NULL AUTO_INCREMENT,
col1 varchar(255) NOT NULL DEFAULT '',
PRIMARY KEY (id)
) ENGINE=INNODB;
CREATE TABLE t2 (
id int(11) NOT NULL AUTO_INCREMENT,
parent_id smallint(3) NOT NULL DEFAULT '0',
col2 varchar(25) NOT NULL DEFAULT '',
PRIMARY KEY (id)
) ENGINE=INNODB;
set join_buffer_size=8192;
set join_cache_level=0;
set @init_time:=now();
SELECT t.*
FROM
t1 t
LEFT JOIN t2 c1 ON c1.parent_id = t.id AND c1.col2 = "val"
LEFT JOIN t2 c2 ON c2.parent_id = t.id AND c2.col2 = "val"
LEFT JOIN t2 c3 ON c3.parent_id = t.id AND c3.col2 = "val"
LEFT JOIN t2 c4 ON c4.parent_id = t.id AND c4.col2 = "val"
LEFT JOIN t2 c5 ON c5.parent_id = t.id AND c5.col2 = "val"
LEFT JOIN t2 c6 ON c6.parent_id = t.id AND c6.col2 = "val"
LEFT JOIN t2 c7 ON c7.parent_id = t.id AND c7.col2 = "val"
LEFT JOIN t2 c8 ON c8.parent_id = t.id AND c8.col2 = "val"
LEFT JOIN t2 c9 ON c9.parent_id = t.id AND c9.col2 = "val"
LEFT JOIN t2 c10 ON c10.parent_id = t.id AND c10.col2 = "val"
LEFT JOIN t2 c11 ON c11.parent_id = t.id AND c11.col2 = "val"
LEFT JOIN t2 c12 ON c12.parent_id = t.id AND c12.col2 = "val"
LEFT JOIN t2 c13 ON c13.parent_id = t.id AND c13.col2 = "val"
LEFT JOIN t2 c14 ON c14.parent_id = t.id AND c14.col2 = "val"
LEFT JOIN t2 c15 ON c15.parent_id = t.id AND c15.col2 = "val"
LEFT JOIN t2 c16 ON c16.parent_id = t.id AND c16.col2 = "val"
LEFT JOIN t2 c17 ON c17.parent_id = t.id AND c17.col2 = "val"
LEFT JOIN t2 c18 ON c18.parent_id = t.id AND c18.col2 = "val"
LEFT JOIN t2 c19 ON c19.parent_id = t.id AND c19.col2 = "val"
LEFT JOIN t2 c20 ON c20.parent_id = t.id AND c20.col2 = "val"
LEFT JOIN t2 c21 ON c21.parent_id = t.id AND c21.col2 = "val"
LEFT JOIN t2 c22 ON c22.parent_id = t.id AND c22.col2 = "val"
LEFT JOIN t2 c23 ON c23.parent_id = t.id AND c23.col2 = "val"
LEFT JOIN t2 c24 ON c24.parent_id = t.id AND c24.col2 = "val"
LEFT JOIN t2 c25 ON c25.parent_id = t.id AND c25.col2 = "val"
ORDER BY
col1;
id col1
select timestampdiff(second, @init_time, now()) <= 1;
timestampdiff(second, @init_time, now()) <= 1
1
set join_cache_level=2;
set @init_time:=now();
SELECT t.*
FROM
t1 t
LEFT JOIN t2 c1 ON c1.parent_id = t.id AND c1.col2 = "val"
LEFT JOIN t2 c2 ON c2.parent_id = t.id AND c2.col2 = "val"
LEFT JOIN t2 c3 ON c3.parent_id = t.id AND c3.col2 = "val"
LEFT JOIN t2 c4 ON c4.parent_id = t.id AND c4.col2 = "val"
LEFT JOIN t2 c5 ON c5.parent_id = t.id AND c5.col2 = "val"
LEFT JOIN t2 c6 ON c6.parent_id = t.id AND c6.col2 = "val"
LEFT JOIN t2 c7 ON c7.parent_id = t.id AND c7.col2 = "val"
LEFT JOIN t2 c8 ON c8.parent_id = t.id AND c8.col2 = "val"
LEFT JOIN t2 c9 ON c9.parent_id = t.id AND c9.col2 = "val"
LEFT JOIN t2 c10 ON c10.parent_id = t.id AND c10.col2 = "val"
LEFT JOIN t2 c11 ON c11.parent_id = t.id AND c11.col2 = "val"
LEFT JOIN t2 c12 ON c12.parent_id = t.id AND c12.col2 = "val"
LEFT JOIN t2 c13 ON c13.parent_id = t.id AND c13.col2 = "val"
LEFT JOIN t2 c14 ON c14.parent_id = t.id AND c14.col2 = "val"
LEFT JOIN t2 c15 ON c15.parent_id = t.id AND c15.col2 = "val"
LEFT JOIN t2 c16 ON c16.parent_id = t.id AND c16.col2 = "val"
LEFT JOIN t2 c17 ON c17.parent_id = t.id AND c17.col2 = "val"
LEFT JOIN t2 c18 ON c18.parent_id = t.id AND c18.col2 = "val"
LEFT JOIN t2 c19 ON c19.parent_id = t.id AND c19.col2 = "val"
LEFT JOIN t2 c20 ON c20.parent_id = t.id AND c20.col2 = "val"
LEFT JOIN t2 c21 ON c21.parent_id = t.id AND c21.col2 = "val"
LEFT JOIN t2 c22 ON c22.parent_id = t.id AND c22.col2 = "val"
LEFT JOIN t2 c23 ON c23.parent_id = t.id AND c23.col2 = "val"
LEFT JOIN t2 c24 ON c24.parent_id = t.id AND c24.col2 = "val"
LEFT JOIN t2 c25 ON c25.parent_id = t.id AND c25.col2 = "val"
ORDER BY
col1;
id col1
select timestampdiff(second, @init_time, now()) <= 1;
timestampdiff(second, @init_time, now()) <= 1
1
EXPLAIN
SELECT t.*
FROM
t1 t
LEFT JOIN t2 c1 ON c1.parent_id = t.id AND c1.col2 = "val"
LEFT JOIN t2 c2 ON c2.parent_id = t.id AND c2.col2 = "val"
LEFT JOIN t2 c3 ON c3.parent_id = t.id AND c3.col2 = "val"
LEFT JOIN t2 c4 ON c4.parent_id = t.id AND c4.col2 = "val"
LEFT JOIN t2 c5 ON c5.parent_id = t.id AND c5.col2 = "val"
LEFT JOIN t2 c6 ON c6.parent_id = t.id AND c6.col2 = "val"
LEFT JOIN t2 c7 ON c7.parent_id = t.id AND c7.col2 = "val"
LEFT JOIN t2 c8 ON c8.parent_id = t.id AND c8.col2 = "val"
LEFT JOIN t2 c9 ON c9.parent_id = t.id AND c9.col2 = "val"
LEFT JOIN t2 c10 ON c10.parent_id = t.id AND c10.col2 = "val"
LEFT JOIN t2 c11 ON c11.parent_id = t.id AND c11.col2 = "val"
LEFT JOIN t2 c12 ON c12.parent_id = t.id AND c12.col2 = "val"
LEFT JOIN t2 c13 ON c13.parent_id = t.id AND c13.col2 = "val"
LEFT JOIN t2 c14 ON c14.parent_id = t.id AND c14.col2 = "val"
LEFT JOIN t2 c15 ON c15.parent_id = t.id AND c15.col2 = "val"
LEFT JOIN t2 c16 ON c16.parent_id = t.id AND c16.col2 = "val"
LEFT JOIN t2 c17 ON c17.parent_id = t.id AND c17.col2 = "val"
LEFT JOIN t2 c18 ON c18.parent_id = t.id AND c18.col2 = "val"
LEFT JOIN t2 c19 ON c19.parent_id = t.id AND c19.col2 = "val"
LEFT JOIN t2 c20 ON c20.parent_id = t.id AND c20.col2 = "val"
LEFT JOIN t2 c21 ON c21.parent_id = t.id AND c21.col2 = "val"
LEFT JOIN t2 c22 ON c22.parent_id = t.id AND c22.col2 = "val"
LEFT JOIN t2 c23 ON c23.parent_id = t.id AND c23.col2 = "val"
LEFT JOIN t2 c24 ON c24.parent_id = t.id AND c24.col2 = "val"
LEFT JOIN t2 c25 ON c25.parent_id = t.id AND c25.col2 = "val"
ORDER BY
col1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t ALL NULL NULL NULL NULL 1 Using temporary; Using filesort
1 SIMPLE c1 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (flat, BNL join)
1 SIMPLE c2 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c3 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c4 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c5 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c6 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c7 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c8 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c9 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c10 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c11 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c12 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c13 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c14 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c15 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c16 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c17 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c18 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c19 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c20 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c21 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c22 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c23 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c24 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
1 SIMPLE c25 ALL NULL NULL NULL NULL 1 Using where; Using join buffer (incremental, BNL join)
set join_buffer_size=default;
set join_cache_level = default;
DROP TABLE t1,t2;
set @@optimizer_switch=@save_optimizer_switch;

6
mysql-test/r/join_nested_jcl6.result
View File

@ -705,18 +705,18 @@ t0.b=t1.b AND
(t8.b=t9.b OR t8.c IS NULL) AND
(t9.a=1);
a b a b a b a b a b a b a b a b a b a b
1 2 3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 4 2 1 2 3 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 4 2 2 2 6 2 2 2 0 2 1 2
1 2 3 2 4 2 1 2 3 2 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 4 2 1 2 4 2 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 4 2 1 2 3 2 3 3 NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 4 2 1 2 4 2 3 3 NULL NULL NULL NULL NULL NULL 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL 1 1
1 2 3 2 5 3 NULL NULL NULL NULL 2 2 6 2 2 2 0 2 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 1 6 2 1 1 NULL NULL 1 2
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL 1 1
1 2 3 2 5 3 NULL NULL NULL NULL 3 3 NULL NULL NULL NULL NULL NULL 1 2

2
mysql-test/r/join_outer_jcl6.result
View File

@ -696,9 +696,9 @@ insert into t2 values (1,3), (2,3);
insert into t3 values (2,4), (3,4);
select * from t1 left join t2 on b1 = a1 left join t3 on c1 = a1 and b1 is null;
a1 a2 b1 b2 c1 c2
3 2 NULL NULL 3 4
1 2 1 3 NULL NULL
2 2 2 3 NULL NULL
3 2 NULL NULL 3 4
explain select * from t1 left join t2 on b1 = a1 left join t3 on c1 = a1 and b1 is null;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL 3

93
mysql-test/t/derived_view.test
View File

@ -1730,6 +1730,99 @@ deallocate prepare stmt;
drop table t1,t2;
set optimizer_switch=@save_optimizer_switch5740;
--echo #
--echo # Bug mdev-5721: possible long key access to a materialized derived table
--echo # (see also the test case for Bug#13261277 that is actually the same bug)
--echo #
CREATE TABLE t1 (
id varchar(255) NOT NULL DEFAULT '',
familyid int(11) DEFAULT NULL,
withdrawndate date DEFAULT NULL,
KEY index_td_familyid_id (familyid,id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
CREATE TABLE t2 (
id int(11) NOT NULL AUTO_INCREMENT,
activefromts datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
shortdescription text,
useraccessfamily varchar(512) DEFAULT NULL,
serialized longtext,
PRIMARY KEY (id)
) ENGINE=MyISAM DEFAULT CHARSET=utf8;
insert into t1 values ('picture/89/1369722032695.pmd',89,NULL);
insert into t1 values ('picture/90/1369832057370.pmd',90,NULL);
insert into t2 values (38,'2013-03-04 07:49:22','desc','CODE','string');
EXPLAIN
SELECT * FROM t2 x,
(SELECT t2.useraccessfamily, t2.serialized AS picturesubuser, COUNT(*)
FROM t2, t1 GROUP BY t2.useraccessfamily, picturesubuser) y
WHERE x.useraccessfamily = y.useraccessfamily;
SELECT * FROM t2 x,
(SELECT t2.useraccessfamily, t2.serialized AS picturesubuser, COUNT(*)
FROM t2, t1 GROUP BY t2.useraccessfamily, picturesubuser) y
WHERE x.useraccessfamily = y.useraccessfamily;
DROP TABLE t1,t2;
--echo #
--echo # Bug#13261277: Unchecked key length caused missing records.
--echo #
CREATE TABLE t1 (
col_varchar varchar(1024) CHARACTER SET utf8 DEFAULT NULL,
stub1 varchar(1024) CHARACTER SET utf8 DEFAULT NULL,
stub2 varchar(1024) CHARACTER SET utf8 DEFAULT NULL,
stub3 varchar(1024) CHARACTER SET utf8 DEFAULT NULL
);
INSERT INTO t1 VALUES
('d','d','l','ther'),
(NULL,'s','NJBIQ','trzetuchv'),
(-715390976,'coul','MYWFB','cfhtrzetu'),
(1696792576,'f','i\'s','c'),
(1,'i','ltpemcfhtr','gsltpemcf'),
(-663027712,'mgsltpemcf','sa','amgsltpem'),
(-1686700032,'JPRVK','i','vamgsltpe'),
(NULL,'STUNB','UNVJV','u'),
(5,'oka','qyihvamgsl','AXSMD'),
(NULL,'tqwmqyihva','h','yntqwmqyi'),
(3,'EGMJN','e','e');
CREATE TABLE t2 (
col_varchar varchar(10) DEFAULT NULL,
col_int INT DEFAULT NULL
);
INSERT INTO t2 VALUES ('d',9);
set optimizer_switch='derived_merge=off,derived_with_keys=on';
SET @save_heap_size= @@max_heap_table_size;
SET @@max_heap_table_size= 16384;
SELECT t2.col_int
FROM t2
RIGHT JOIN ( SELECT * FROM t1 ) AS dt
ON t2.col_varchar = dt.col_varchar
WHERE t2.col_int IS NOT NULL ;
--echo # Shouldn't use auto_key0 for derived table
EXPLAIN
SELECT t2.col_int
FROM t2
RIGHT JOIN ( SELECT * FROM t1 ) AS dt
ON t2.col_varchar = dt.col_varchar
WHERE t2.col_int IS NOT NULL ;
SET @@max_heap_table_size= @save_heap_size;
SET optimizer_switch=@save_optimizer_switch;
DROP TABLE t1,t2;
--echo #
--echo # end of 5.3 tests
--echo #

129
mysql-test/t/join_cache.test
View File

@ -3656,5 +3656,134 @@ explain select * from t0,t1 left join t2 on t1.b=t2.b order by t0.a, t1.a;
drop table t0,t1,t2;
--echo #
--echo # mdev-6292: huge performance degradation for a sequence
--echo # of LEFT JOIN operations when using join buffer
--echo #
--source include/have_innodb.inc
CREATE TABLE t1 (
id int(11) NOT NULL AUTO_INCREMENT,
col1 varchar(255) NOT NULL DEFAULT '',
PRIMARY KEY (id)
) ENGINE=INNODB;
CREATE TABLE t2 (
id int(11) NOT NULL AUTO_INCREMENT,
parent_id smallint(3) NOT NULL DEFAULT '0',
col2 varchar(25) NOT NULL DEFAULT '',
PRIMARY KEY (id)
) ENGINE=INNODB;
set join_buffer_size=8192;
set join_cache_level=0;
set @init_time:=now();
SELECT t.*
FROM
t1 t
LEFT JOIN t2 c1 ON c1.parent_id = t.id AND c1.col2 = "val"
LEFT JOIN t2 c2 ON c2.parent_id = t.id AND c2.col2 = "val"
LEFT JOIN t2 c3 ON c3.parent_id = t.id AND c3.col2 = "val"
LEFT JOIN t2 c4 ON c4.parent_id = t.id AND c4.col2 = "val"
LEFT JOIN t2 c5 ON c5.parent_id = t.id AND c5.col2 = "val"
LEFT JOIN t2 c6 ON c6.parent_id = t.id AND c6.col2 = "val"
LEFT JOIN t2 c7 ON c7.parent_id = t.id AND c7.col2 = "val"
LEFT JOIN t2 c8 ON c8.parent_id = t.id AND c8.col2 = "val"
LEFT JOIN t2 c9 ON c9.parent_id = t.id AND c9.col2 = "val"
LEFT JOIN t2 c10 ON c10.parent_id = t.id AND c10.col2 = "val"
LEFT JOIN t2 c11 ON c11.parent_id = t.id AND c11.col2 = "val"
LEFT JOIN t2 c12 ON c12.parent_id = t.id AND c12.col2 = "val"
LEFT JOIN t2 c13 ON c13.parent_id = t.id AND c13.col2 = "val"
LEFT JOIN t2 c14 ON c14.parent_id = t.id AND c14.col2 = "val"
LEFT JOIN t2 c15 ON c15.parent_id = t.id AND c15.col2 = "val"
LEFT JOIN t2 c16 ON c16.parent_id = t.id AND c16.col2 = "val"
LEFT JOIN t2 c17 ON c17.parent_id = t.id AND c17.col2 = "val"
LEFT JOIN t2 c18 ON c18.parent_id = t.id AND c18.col2 = "val"
LEFT JOIN t2 c19 ON c19.parent_id = t.id AND c19.col2 = "val"
LEFT JOIN t2 c20 ON c20.parent_id = t.id AND c20.col2 = "val"
LEFT JOIN t2 c21 ON c21.parent_id = t.id AND c21.col2 = "val"
LEFT JOIN t2 c22 ON c22.parent_id = t.id AND c22.col2 = "val"
LEFT JOIN t2 c23 ON c23.parent_id = t.id AND c23.col2 = "val"
LEFT JOIN t2 c24 ON c24.parent_id = t.id AND c24.col2 = "val"
LEFT JOIN t2 c25 ON c25.parent_id = t.id AND c25.col2 = "val"
ORDER BY
col1;
select timestampdiff(second, @init_time, now()) <= 1;
set join_cache_level=2;
set @init_time:=now();
SELECT t.*
FROM
t1 t
LEFT JOIN t2 c1 ON c1.parent_id = t.id AND c1.col2 = "val"
LEFT JOIN t2 c2 ON c2.parent_id = t.id AND c2.col2 = "val"
LEFT JOIN t2 c3 ON c3.parent_id = t.id AND c3.col2 = "val"
LEFT JOIN t2 c4 ON c4.parent_id = t.id AND c4.col2 = "val"
LEFT JOIN t2 c5 ON c5.parent_id = t.id AND c5.col2 = "val"
LEFT JOIN t2 c6 ON c6.parent_id = t.id AND c6.col2 = "val"
LEFT JOIN t2 c7 ON c7.parent_id = t.id AND c7.col2 = "val"
LEFT JOIN t2 c8 ON c8.parent_id = t.id AND c8.col2 = "val"
LEFT JOIN t2 c9 ON c9.parent_id = t.id AND c9.col2 = "val"
LEFT JOIN t2 c10 ON c10.parent_id = t.id AND c10.col2 = "val"
LEFT JOIN t2 c11 ON c11.parent_id = t.id AND c11.col2 = "val"
LEFT JOIN t2 c12 ON c12.parent_id = t.id AND c12.col2 = "val"
LEFT JOIN t2 c13 ON c13.parent_id = t.id AND c13.col2 = "val"
LEFT JOIN t2 c14 ON c14.parent_id = t.id AND c14.col2 = "val"
LEFT JOIN t2 c15 ON c15.parent_id = t.id AND c15.col2 = "val"
LEFT JOIN t2 c16 ON c16.parent_id = t.id AND c16.col2 = "val"
LEFT JOIN t2 c17 ON c17.parent_id = t.id AND c17.col2 = "val"
LEFT JOIN t2 c18 ON c18.parent_id = t.id AND c18.col2 = "val"
LEFT JOIN t2 c19 ON c19.parent_id = t.id AND c19.col2 = "val"
LEFT JOIN t2 c20 ON c20.parent_id = t.id AND c20.col2 = "val"
LEFT JOIN t2 c21 ON c21.parent_id = t.id AND c21.col2 = "val"
LEFT JOIN t2 c22 ON c22.parent_id = t.id AND c22.col2 = "val"
LEFT JOIN t2 c23 ON c23.parent_id = t.id AND c23.col2 = "val"
LEFT JOIN t2 c24 ON c24.parent_id = t.id AND c24.col2 = "val"
LEFT JOIN t2 c25 ON c25.parent_id = t.id AND c25.col2 = "val"
ORDER BY
col1;
select timestampdiff(second, @init_time, now()) <= 1;
EXPLAIN
SELECT t.*
FROM
t1 t
LEFT JOIN t2 c1 ON c1.parent_id = t.id AND c1.col2 = "val"
LEFT JOIN t2 c2 ON c2.parent_id = t.id AND c2.col2 = "val"
LEFT JOIN t2 c3 ON c3.parent_id = t.id AND c3.col2 = "val"
LEFT JOIN t2 c4 ON c4.parent_id = t.id AND c4.col2 = "val"
LEFT JOIN t2 c5 ON c5.parent_id = t.id AND c5.col2 = "val"
LEFT JOIN t2 c6 ON c6.parent_id = t.id AND c6.col2 = "val"
LEFT JOIN t2 c7 ON c7.parent_id = t.id AND c7.col2 = "val"
LEFT JOIN t2 c8 ON c8.parent_id = t.id AND c8.col2 = "val"
LEFT JOIN t2 c9 ON c9.parent_id = t.id AND c9.col2 = "val"
LEFT JOIN t2 c10 ON c10.parent_id = t.id AND c10.col2 = "val"
LEFT JOIN t2 c11 ON c11.parent_id = t.id AND c11.col2 = "val"
LEFT JOIN t2 c12 ON c12.parent_id = t.id AND c12.col2 = "val"
LEFT JOIN t2 c13 ON c13.parent_id = t.id AND c13.col2 = "val"
LEFT JOIN t2 c14 ON c14.parent_id = t.id AND c14.col2 = "val"
LEFT JOIN t2 c15 ON c15.parent_id = t.id AND c15.col2 = "val"
LEFT JOIN t2 c16 ON c16.parent_id = t.id AND c16.col2 = "val"
LEFT JOIN t2 c17 ON c17.parent_id = t.id AND c17.col2 = "val"
LEFT JOIN t2 c18 ON c18.parent_id = t.id AND c18.col2 = "val"
LEFT JOIN t2 c19 ON c19.parent_id = t.id AND c19.col2 = "val"
LEFT JOIN t2 c20 ON c20.parent_id = t.id AND c20.col2 = "val"
LEFT JOIN t2 c21 ON c21.parent_id = t.id AND c21.col2 = "val"
LEFT JOIN t2 c22 ON c22.parent_id = t.id AND c22.col2 = "val"
LEFT JOIN t2 c23 ON c23.parent_id = t.id AND c23.col2 = "val"
LEFT JOIN t2 c24 ON c24.parent_id = t.id AND c24.col2 = "val"
LEFT JOIN t2 c25 ON c25.parent_id = t.id AND c25.col2 = "val"
ORDER BY
col1;
set join_buffer_size=default;
set join_cache_level = default;
DROP TABLE t1,t2;
# this must be the last command in the file
set @@optimizer_switch=@save_optimizer_switch;