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mariadb/mysql-test/r/subselect_innodb.result
Sergey Petrunya 244d4b532a MDEV-6081: ORDER BY+ref(const): selectivity is very incorrect (MySQL Bug#14338686) 
Add a testcase and backport this fix:

Bug#14338686: MYSQL IS GENERATING DIFFERENT AND SLOWER
              (IN NEWER VERSIONS) EXECUTION PLAN
PROBLEM:
While checking for an index to sort for the order by clause
in this query
"SELECT datestamp FROM contractStatusHistory WHERE
contract_id = contracts.id ORDER BY datestamp asc limit 1;"

we do not calculate the number of rows to be examined correctly.
As a result we choose index 'idx_contractStatusHistory_datestamp'
defined on the 'datestamp' field, rather than choosing index
'contract_id'. And hence the lower performance.

ANALYSIS:
While checking if an index is present to give the records in
sorted order(datestamp), we consider the selectivity of the
'ref_key'(contract_id here) using 'table->quick_condition_rows'.
'ref_key' here can be an index from 'REF_ACCESS' or from 'RANGE'.

As this is a 'REF_ACCESS', 'table->quick_condition_rows' is not
set to the actual value which is 2. Instead is set to the number
of tuples present in the table indicating that every row that
is selected would be satisfying the condition present in the query.

Hence, the selectivity becomes 1 even when we choose the index
on the order by column instead of the join_condition.

But, in reality as only 2 rows satisy the condition, we need to
examine half of the entire data set to get one tuple when we
choose index on the order by column.
Had we chosen the 'REF_ACCESS' we would have examined only 2 tuples.
Hence the delay in executing the query specified.
  
FIX:
While calculating the selectivity of the ref_key:
For REF_ACCESS consider quick_rows[ref_key] if range 
optimizer has an estimate for this key. Else consider 
'rec_per_key' statistic.
For RANGE ACCESS consider 'table->quick_condition_rows'.
2014-04-12 01:01:32 +04:00

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set @subselect_innodb_tmp=@@optimizer_switch;
set optimizer_switch='mrr=on,mrr_sort_keys=on,index_condition_pushdown=on';
drop table if exists t1,t2,t3;
CREATE TABLE t1
(
FOLDERID VARCHAR(32)BINARY NOT NULL
, FOLDERNAME VARCHAR(255)BINARY NOT NULL
, CREATOR VARCHAR(255)BINARY
, CREATED TIMESTAMP NOT NULL
, DESCRIPTION VARCHAR(255)BINARY
, FOLDERTYPE INTEGER NOT NULL
, MODIFIED TIMESTAMP
, MODIFIER VARCHAR(255)BINARY
, FOLDERSIZE INTEGER NOT NULL
, PARENTID VARCHAR(32)BINARY
, REPID VARCHAR(32)BINARY
, ORIGINATOR INTEGER
, PRIMARY KEY ( FOLDERID )
) ENGINE=InnoDB;
CREATE INDEX FFOLDERID_IDX ON t1 (FOLDERID);
CREATE INDEX CMFLDRPARNT_IDX ON t1 (PARENTID);
INSERT INTO t1 VALUES("0c9aab05b15048c59bc35c8461507deb", "System", "System", "2003-06-05 16:30:00", "The system content repository folder.", "3", "2003-06-05 16:30:00", "System", "0", NULL, "9c9aab05b15048c59bc35c8461507deb", "1");
INSERT INTO t1 VALUES("2f6161e879db43c1a5b82c21ddc49089", "Default", "System", "2003-06-09 10:52:02", "The default content repository folder.", "3", "2003-06-05 16:30:00", "System", "0", NULL, "03eea05112b845949f3fd03278b5fe43", "1");
INSERT INTO t1 VALUES("c373e9f5ad0791724315444553544200", "AddDocumentTest", "admin", "2003-06-09 10:51:25", "Movie Reviews", "0", "2003-06-09 10:51:25", "admin", "0", "2f6161e879db43c1a5b82c21ddc49089", "03eea05112b845949f3fd03278b5fe43", NULL);
SELECT 'c373e9f5ad0791a0dab5444553544200' IN(SELECT t1.FOLDERID FROM t1 WHERE t1.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t1.FOLDERNAME = 'Level1');
'c373e9f5ad0791a0dab5444553544200' IN(SELECT t1.FOLDERID FROM t1 WHERE t1.PARENTID='2f6161e879db43c1a5b82c21ddc49089' AND t1.FOLDERNAME = 'Level1')
0
drop table t1;
create table t1 (a int) engine=innodb;
create table t2 (a int) engine=innodb;
create table t3 (a int) engine=innodb;
insert into t1 values (1),(2),(3),(4);
insert into t2 values (10),(20),(30),(40);
insert into t3 values (1),(2),(10),(50);
select a from t3 where t3.a in (select a from t1 where a <= 3 union select * from t2 where a <= 30);
a
1
2
10
drop table t1,t2,t3;
CREATE TABLE t1 (
processor_id INTEGER NOT NULL,
PRIMARY KEY (processor_id)
) ENGINE=InnoDB;
CREATE TABLE t3 (
yod_id BIGINT UNSIGNED AUTO_INCREMENT NOT NULL,
login_processor INTEGER UNSIGNED ,
PRIMARY KEY (yod_id)
) ENGINE=InnoDB;
CREATE TABLE t2 (
processor_id INTEGER NOT NULL,
yod_id BIGINT UNSIGNED NOT NULL,
PRIMARY KEY (processor_id, yod_id),
INDEX (processor_id),
INDEX (yod_id),
FOREIGN KEY (processor_id) REFERENCES t1(processor_id),
FOREIGN KEY (yod_id) REFERENCES t3(yod_id)
) ENGINE=InnoDB;
INSERT INTO t1 VALUES (1),(2),(3);
INSERT INTO t3 VALUES (1,1),(2,2),(3,3);
INSERT INTO t2 VALUES (1,1),(2,2),(3,3);
SELECT distinct p1.processor_id, (SELECT y.yod_id FROM t1 p2, t2 y WHERE p2.processor_id = p1.processor_id and p2.processor_id = y.processor_id) FROM t1 p1;
processor_id (SELECT y.yod_id FROM t1 p2, t2 y WHERE p2.processor_id = p1.processor_id and p2.processor_id = y.processor_id)
1 1
2 2
3 3
drop table t2,t1,t3;
CREATE TABLE t1 (
id int(11) NOT NULL default '0',
b int(11) default NULL,
c char(3) default NULL,
PRIMARY KEY (id),
KEY t2i1 (b)
) ENGINE=innodb DEFAULT CHARSET=latin1;
INSERT INTO t1 VALUES (0,0,'GPL'),(1,0,'GPL'),(2,1,'GPL'),(3,2,'GPL');
CREATE TABLE t2 (
id int(11) NOT NULL default '0',
b int(11) default NULL,
c char(3) default NULL,
PRIMARY KEY (id),
KEY t2i (b)
) ENGINE=innodb DEFAULT CHARSET=latin1;
INSERT INTO t2 VALUES (0,0,'GPL'),(1,0,'GPL'),(2,1,'GPL'),(3,2,'GPL');
select (select max(id) from t2 where b=1 group by b) as x,b from t1 where b=1;
x b
2 1
drop table t1,t2;
create table t1 (id int not null, value char(255), primary key(id)) engine=innodb;
create table t2 (id int not null, value char(255)) engine=innodb;
insert into t1 values (1,'a'),(2,'b');
insert into t2 values (1,'z'),(2,'x');
select t2.id,t2.value,(select t1.value from t1 where t1.id=t2.id) from t2;
id value (select t1.value from t1 where t1.id=t2.id)
1 z a
2 x b
select t2.id,t2.value,(select t1.value from t1 where t1.id=t2.id) from t2;
id value (select t1.value from t1 where t1.id=t2.id)
1 z a
2 x b
drop table t1,t2;
create table t1 (a int, b int) engine=innodb;
insert into t1 values (1,2), (1,3), (2,3), (2,4), (2,5), (3,4), (4,5), (4,100);
create table t2 (a int) engine=innodb;
insert into t2 values (1),(2),(3),(4);
select a, sum(b) as b from t1 group by a having b > (select max(a) from t2);
a b
1 5
2 12
4 105
drop table t1, t2;
CREATE TABLE `t1` ( `unit` varchar(50) NOT NULL default '', `ingredient` varchar(50) NOT NULL default '') ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE `t2` ( `ingredient` varchar(50) NOT NULL default '', `unit` varchar(50) NOT NULL default '', PRIMARY KEY (ingredient, unit)) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO `t1` VALUES ('xx','yy');
INSERT INTO `t2` VALUES ('yy','xx');
SELECT R.unit, R.ingredient FROM t1 R WHERE R.ingredient IN (SELECT N.ingredient FROM t2 N WHERE N.unit = R.unit);
unit ingredient
xx yy
drop table t1, t2;
CREATE TABLE t1 (
id INT NOT NULL auto_increment,
date1 DATE, coworkerid INT,
description VARCHAR(255),
sum_used DOUBLE,
sum_remaining DOUBLE,
comments VARCHAR(255),
PRIMARY KEY(id)
) engine=innodb;
insert into t1 values (NULL, '1999-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1999-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1999-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1998-01-01', 1,'test', 22, 33, 'comment'), (NULL, '1998-01-01', 1,'test', 22, 33, 'comment'), (NULL, '2004-01-01', 1,'test', 22, 33, 'comment'), (NULL, '2004-01-01', 1,'test', 22, 33, 'comment');
SELECT DISTINCT
(SELECT sum(sum_used) FROM t1 WHERE sum_used > 0 AND year(date1) <= '2004') as somallontvangsten,
(SELECT sum(sum_used) FROM t1 WHERE sum_used < 0 AND year(date1) <= '2004') as somalluitgaven
FROM t1;
somallontvangsten somalluitgaven
154 NULL
select * from t1;
id date1 coworkerid description sum_used sum_remaining comments
1 1999-01-01 1 test 22 33 comment
2 1999-01-01 1 test 22 33 comment
3 1999-01-01 1 test 22 33 comment
4 1998-01-01 1 test 22 33 comment
5 1998-01-01 1 test 22 33 comment
6 2004-01-01 1 test 22 33 comment
7 2004-01-01 1 test 22 33 comment
drop table t1;
CREATE TABLE `t1` ( `a` char(3) NOT NULL default '', `b` char(3) NOT NULL default '', `c` char(3) NOT NULL default '', PRIMARY KEY (`a`,`b`,`c`)) ENGINE=InnoDB;
CREATE TABLE t2 LIKE t1;
INSERT INTO t1 VALUES (1,1,1);
INSERT INTO t2 VALUES (1,1,1);
PREPARE my_stmt FROM "SELECT t1.b, count(*) FROM t1 group by t1.b having
count(*) > ALL (SELECT COUNT(*) FROM t2 WHERE t2.a=1 GROUP By t2.b)";
EXECUTE my_stmt;
b count(*)
EXECUTE my_stmt;
b count(*)
deallocate prepare my_stmt;
drop table t1,t2;
CREATE TABLE t1 (
school_name varchar(45) NOT NULL,
country varchar(45) NOT NULL,
funds_requested float NOT NULL,
schooltype varchar(45) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
insert into t1 values ("the school", "USA", 1200, "Human");
select count(country) as countrycount, sum(funds_requested) as smcnt,
country, (select sum(funds_requested) from t1) as total_funds
from t1
group by country;
countrycount smcnt country total_funds
1 1200 USA 1200
select count(country) as countrycount, sum(funds_requested) as smcnt,
country, (select sum(funds_requested) from t1) as total_funds
from t1
group by country;
countrycount smcnt country total_funds
1 1200 USA 1200
drop table t1;
CREATE TABLE `t1` (
`t3_id` int NOT NULL,
`t1_id` int NOT NULL,
PRIMARY KEY (`t1_id`)
);
CREATE TABLE `t2` (
`t2_id` int NOT NULL,
`t1_id` int NOT NULL,
`b` int NOT NULL,
PRIMARY KEY (`t2_id`),
UNIQUE KEY `idx_t2_t1_b` (`t1_id`,`b`)
) ENGINE=InnoDB;
CREATE TABLE `t3` (
`t3_id` int NOT NULL
);
INSERT INTO `t3` VALUES (3);
select
(SELECT rs.t2_id
FROM t2 rs
WHERE rs.t1_id=
(SELECT lt.t1_id
FROM t1 lt
WHERE lt.t3_id=a.t3_id)
ORDER BY b DESC LIMIT 1)
from t3 AS a;
(SELECT rs.t2_id
FROM t2 rs
WHERE rs.t1_id=
(SELECT lt.t1_id
FROM t1 lt
WHERE lt.t3_id=a.t3_id)
ORDER BY b DESC LIMIT 1)
NULL
DROP PROCEDURE IF EXISTS p1;
create procedure p1()
begin
declare done int default 3;
repeat
select
(SELECT rs.t2_id
FROM t2 rs
WHERE rs.t1_id=
(SELECT lt.t1_id
FROM t1 lt
WHERE lt.t3_id=a.t3_id)
ORDER BY b DESC LIMIT 1) as x
from t3 AS a;
set done= done-1;
until done <= 0 end repeat;
end//
call p1();
x
NULL
x
NULL
x
NULL
call p1();
x
NULL
x
NULL
x
NULL
call p1();
x
NULL
x
NULL
x
NULL
drop procedure p1;
drop tables t1,t2,t3;
#
# Bug #58756
# Crash in heap_rrnd on query with HAVING ... IN (subquery) + LIMIT
#
CREATE TABLE t1 (
col_time_key time DEFAULT NULL,
col_datetime_key datetime DEFAULT NULL,
col_varchar_nokey varchar(1) DEFAULT NULL,
KEY col_time_key (col_time_key),
KEY col_datetime_key (col_datetime_key)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t1 VALUES ('17:53:30','2005-11-10 12:40:29','h');
INSERT INTO t1 VALUES ('11:35:49','2009-04-25 00:00:00','b');
INSERT INTO t1 VALUES (NULL,'2002-11-27 00:00:00','s');
INSERT INTO t1 VALUES ('06:01:40','2004-01-26 20:32:32','e');
INSERT INTO t1 VALUES ('05:45:11','2007-10-26 11:41:40','j');
INSERT INTO t1 VALUES ('00:00:00','2005-10-07 00:00:00','e');
INSERT INTO t1 VALUES ('00:00:00','2000-07-15 05:00:34','f');
INSERT INTO t1 VALUES ('06:11:01','2000-04-03 16:33:32','v');
INSERT INTO t1 VALUES ('13:02:46',NULL,'x');
INSERT INTO t1 VALUES ('21:44:25','2001-04-25 01:26:12','m');
INSERT INTO t1 VALUES ('22:43:58','2000-12-27 00:00:00','c');
CREATE TABLE t2 (
col_time_key time DEFAULT NULL,
col_datetime_key datetime DEFAULT NULL,
col_varchar_nokey varchar(1) DEFAULT NULL,
KEY col_time_key (col_time_key),
KEY col_datetime_key (col_datetime_key)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t2 VALUES ('11:28:45','2004-10-11 18:13:16','w');
SELECT col_time_key, col_datetime_key
FROM
( SELECT * FROM t1 ) AS table1
HAVING ( 'r' , 'e' ) IN
( SELECT col_varchar_nokey , col_varchar_nokey FROM t2 )
ORDER BY col_datetime_key
LIMIT 10;
col_time_key col_datetime_key
DROP TABLE t1;
DROP TABLE t2;
# End of Bug #58756
#
# Bug#60085 crash in Item::save_in_field() with time data type
#
CREATE TABLE t1(a date, b int, unique(b), unique(a), key(b)) engine=innodb;
INSERT INTO t1 VALUES ('2011-05-13', 0);
SELECT * FROM t1 WHERE b < (SELECT CAST(a as date) FROM t1 GROUP BY a);
a b
2011-05-13 0
Warnings:
Warning 1292 Incorrect datetime value: '0'
DROP TABLE t1;
#
# Bug #11766300 59387: FAILING ASSERTION: CURSOR->POS_STATE == 1997660512 (BTR_PCUR_IS_POSITIONE
#
CREATE TABLE t1 (a INT) ENGINE=INNODB;
INSERT INTO t1 VALUES (0);
CREATE TABLE t2 (d BINARY(2), PRIMARY KEY (d(1)), UNIQUE KEY (d)) ENGINE=INNODB;
SELECT 1 FROM t1 WHERE NOT EXISTS
(SELECT 1 FROM t2 WHERE d = (SELECT d FROM t2 WHERE a >= 1) ORDER BY d);
1
1
EXPLAIN SELECT 1 FROM t1 WHERE NOT EXISTS
(SELECT 1 FROM t2 WHERE d = (SELECT d FROM t2 WHERE a >= 1) ORDER BY d);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 1 Using where
2 DEPENDENT SUBQUERY t2 eq_ref PRIMARY,d PRIMARY 1 func 1 Using where
3 DEPENDENT SUBQUERY t2 index NULL d 2 NULL 1 Using where; Using index
DROP TABLE t2;
CREATE TABLE t2 (b INT, c INT, UNIQUE KEY (b), UNIQUE KEY (b, c )) ENGINE=INNODB;
INSERT INTO t2 VALUES (1, 1);
SELECT 1 FROM t1
WHERE a != (SELECT 1 FROM t2 WHERE a <=> b OR a > '' AND 6 = 7 ORDER BY b, c);
1
DROP TABLE t1, t2;
#
# Bug #13639204 64111: CRASH ON SELECT SUBQUERY WITH NON UNIQUE
# INDEX
#
CREATE TABLE t1 (
id int
) ENGINE=InnoDB;
INSERT INTO t1 (id) VALUES (11);
CREATE TABLE t2 (
t1_id int,
position int,
KEY t1_id (t1_id),
KEY t1_id_position (t1_id,position)
) ENGINE=InnoDB;
EXPLAIN SELECT
(SELECT position FROM t2
WHERE t2.t1_id = t1.id
ORDER BY t2.t1_id , t2.position
LIMIT 10,1
) AS maxkey
FROM t1
LIMIT 1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 1
2 DEPENDENT SUBQUERY t2 ref t1_id,t1_id_position t1_id_position 5 test.t1.id 1 Using where; Using index
SELECT
(SELECT position FROM t2
WHERE t2.t1_id = t1.id
ORDER BY t2.t1_id , t2.position
LIMIT 10,1
) AS maxkey
FROM t1
LIMIT 1;
maxkey
NULL
DROP TABLE t1,t2;
End of 5.1 tests
#
# lp:827416 Crash in select_describe() on EXPLAIN with DISTINCT in nested subqueries
#
CREATE TABLE t3 ( b int) ENGINE=InnoDB;
CREATE TABLE t2 ( c int) ENGINE=InnoDB;
CREATE TABLE t1 ( a int NOT NULL , PRIMARY KEY (a)) ENGINE=InnoDB;
EXPLAIN SELECT *
FROM t1
WHERE t1.a = (
SELECT SUM( c )
FROM t2
WHERE (SELECT DISTINCT b FROM t3) > 0);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
3 SUBQUERY t3 ALL NULL NULL NULL NULL 1 Using temporary
SELECT *
FROM t1
WHERE t1.a = (
SELECT SUM( c )
FROM t2
WHERE (SELECT DISTINCT b FROM t3) > 0);
a
DROP TABLE t1, t2, t3;
#
# lp:858148 Fourth crash in select_describe() with nested subqueries
#
CREATE TABLE t1 ( f1 int(11)) ENGINE=InnoDB;
CREATE TABLE t2 ( f1 int(11), f2 int(11), PRIMARY KEY (f1)) ;
CREATE TABLE t3 ( f3 int(11)) ENGINE=InnoDB;
EXPLAIN
SELECT MAX( f1 ) FROM t2
WHERE f2 >= (
SELECT SUM( f1 )
FROM t1
WHERE EXISTS (
SELECT f3
FROM t3
GROUP BY 1
)
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
3 SUBQUERY t3 ALL NULL NULL NULL NULL 1
SELECT MAX( f1 ) FROM t2
WHERE f2 >= (
SELECT SUM( f1 )
FROM t1
WHERE EXISTS (
SELECT f3
FROM t3
GROUP BY 1
)
);
MAX( f1 )
NULL
drop table t1, t2, t3;
#
# LP BUG#1006231 crash in select_describe
#
create table t1(a1 int) ENGINE=InnoDB;
insert into t1 values (1);
explain
select 1 from t1 where 1 like (select 1 from t1 where 1 <=> (select 1 from t1 group by a1));
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 1
2 SUBQUERY t1 ALL NULL NULL NULL NULL 1
3 SUBQUERY t1 ALL NULL NULL NULL NULL 1 Using temporary; Using filesort
select 1 from t1 where 1 like (select 1 from t1 where 1 <=> (select 1 from t1 group by a1));
1
1
drop table t1;
#
# MDEV-3988 crash in create_tmp_table
#
drop table if exists `t1`,`t2`;
Warnings:
Note 1051 Unknown table 'test.t1'
Note 1051 Unknown table 'test.t2'
create table `t1`(`a` char(1) character set utf8)engine=innodb;
create table `t2`(`b` char(1) character set utf8)engine=memory;
select distinct (select 1 from `t2` where `a`) `d2` from `t1`;
d2
select distinct (select 1 from `t2` where `a`) `d2`, a from `t1`;
d2 a
select distinct a, (select 1 from `t2` where `a`) `d2` from `t1`;
a d2
select distinct (1 + (select 1 from `t2` where `a`)) `d2` from `t1`;
d2
drop table t1,t2;
#
# MDEV-4042: Assertion `table->key_read == 0' fails in close_thread_table on EXPLAIN with GROUP BY and HAVING in EXISTS SQ,
# MDEV-4536: ...sql/sql_base.cc:1598: bool close_thread_table(THD*, TABLE**): Assertion `table->key_read == 0' failed.
CREATE TABLE t1 (a INT) ENGINE=InnoDB;
CREATE TABLE t2 (b INT PRIMARY KEY, c INT) ENGINE=InnoDB;
CREATE TABLE t3 (d INT) ENGINE=InnoDB;
EXPLAIN
SELECT * FROM t1 WHERE EXISTS ( SELECT b FROM t2, t3 GROUP BY b HAVING b != 3 );
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY t2 index NULL PRIMARY 4 NULL 1 Using index; Using temporary; Using filesort
2 SUBQUERY t3 ALL NULL NULL NULL NULL 1 Using join buffer (flat, BNL join)
SELECT * FROM t1 WHERE EXISTS ( SELECT b FROM t2, t3 GROUP BY b HAVING b != 3 );
a
DROP TABLE t1,t2,t3;
CREATE TABLE t1 (
pk int auto_increment primary key,
col_int_key int(11),
key col_int_key (col_int_key),col_varchar_key varchar(128),
key (col_varchar_key)
) engine=innodb;
EXPLAIN
SELECT 1 FROM t1 AS alias1
WHERE EXISTS ( SELECT SQ2_alias1 . col_int_key AS SQ2_field1
FROM ( t1 AS SQ2_alias1 RIGHT OUTER JOIN
t1 AS SQ2_alias2 ON (SQ2_alias2 . col_int_key = SQ2_alias1 . col_int_key )
)
GROUP BY SQ2_field1
HAVING SQ2_alias1 . col_int_key >= 7
);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
2 SUBQUERY SQ2_alias2 index NULL col_int_key 5 NULL 1 Using index; Using temporary; Using filesort
2 SUBQUERY SQ2_alias1 ref col_int_key col_int_key 5 test.SQ2_alias2.col_int_key 1 Using where; Using index
SELECT 1 FROM t1 AS alias1
WHERE EXISTS ( SELECT SQ2_alias1 . col_int_key AS SQ2_field1
FROM ( t1 AS SQ2_alias1 RIGHT OUTER JOIN
t1 AS SQ2_alias2 ON (SQ2_alias2 . col_int_key = SQ2_alias1 . col_int_key )
)
GROUP BY SQ2_field1
HAVING SQ2_alias1 . col_int_key >= 7
);
1
drop table t1;
set optimizer_switch=@subselect_innodb_tmp;
#
# MDEV-6041: ORDER BY+subqueries: subquery_table.key=outer_table.col is not recongized as binding
#
create table t1(a int) engine=innodb;
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2(
id int primary key,
key1 int,
col1 int,
key(key1)
) engine=innodb;
insert into t2
select
A.a + B.a*10 + C.a*100 + D.a* 1000,
A.a + 10*B.a,
123456
from t1 A, t1 B, t1 C, t1 D;
# Table tsubq:
# - must use 'ref' (not 'index'), and must not use 'Using filesort'
# - shows a bad estimate for 'rows' (but I'm not sure if one can do better w/o histograms)
explain select
(SELECT
concat(id, '-', key1, '-', col1)
FROM t2
WHERE t2.key1 = t1.a
ORDER BY t2.id ASC LIMIT 1)
from
t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 10
2 DEPENDENT SUBQUERY t2 ref key1 key1 5 test.t1.a 1 Using where
#
# MDEV-6081: ORDER BY+ref(const): selectivity is very incorrect (MySQL Bug#14338686)
#
alter table t2 add key2 int;
update t2 set key2=key1;
alter table t2 add key(key2);
analyze table t2;
Table Op Msg_type Msg_text
test.t2 analyze status OK
flush tables;
# Table tsubq must use 'ref' + Using filesort (not 'index' w/o filesort)
explain select
(SELECT
concat(id, '-', key1, '-', col1)
FROM t2
WHERE t2.key1 = t1.a
ORDER BY t2.key2 ASC LIMIT 1)
from
t1;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL #
2 DEPENDENT SUBQUERY t2 ref key1 key1 5 test.t1.a # Using where; Using filesort
drop table t1,t2;
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