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072073c09e
The patch differs from the original MySQL patch as follows:
- All test case differences have been reviewed one by one, and
care has been taken to restore the original plan so that each
test case executes the code path it was designed for.
- A bug was found and fixed in MariaDB 5.3 in
Item_allany_subselect::cleanup().
- ORDER BY is not removed because we are unsure of all effects,
and it would prevent enabling ORDER BY ... LIMIT subqueries.
- ref_pointer_array.m_size is not adjusted because we don't do
array bounds checking, and because it looks risky.
Original comment by Jorgen Loland:
-------------------------------------------------------------
WL#5953 - Optimize away useless subquery clauses
For IN/ALL/ANY/SOME/EXISTS subqueries, the following clauses are
meaningless:
* ORDER BY (since we don't support LIMIT in these subqueries)
* DISTINCT
* GROUP BY if there is no HAVING clause and no aggregate
functions
This WL detects and optimizes away these useless parts of the
query during JOIN::prepare()
393 lines
14 KiB
Text
393 lines
14 KiB
Text
#
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# LP BUG#643424 valgrind warning in choose_subquery_plan()
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#
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CREATE TABLE t1 (
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pk int(11) NOT NULL AUTO_INCREMENT,
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c1 int(11) DEFAULT NULL,
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c2 int(11) DEFAULT NULL,
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PRIMARY KEY (pk),
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KEY c2 (c2));
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INSERT INTO t1 VALUES (1,NULL,2);
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INSERT INTO t1 VALUES (2,7,9);
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INSERT INTO t1 VALUES (9,NULL,8);
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CREATE TABLE t2 (
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pk int(11) NOT NULL AUTO_INCREMENT,
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c1 int(11) DEFAULT NULL,
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c2 int(11) DEFAULT NULL,
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PRIMARY KEY (pk),
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KEY c2 (c2));
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INSERT INTO t2 VALUES (1,1,7);
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set @save_optimizer_switch=@@optimizer_switch;
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set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
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SELECT pk FROM t1 WHERE (c2, c1) IN (SELECT c2, c2 FROM t2);
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pk
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set session optimizer_switch=@save_optimizer_switch;
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drop table t1, t2;
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#
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# LP BUG#652727 Crash in create_ref_for_key()
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#
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CREATE TABLE t2 (
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pk int(11) NOT NULL AUTO_INCREMENT,
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c1 int(11) DEFAULT NULL,
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PRIMARY KEY (pk));
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INSERT INTO t2 VALUES (10,7);
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INSERT INTO t2 VALUES (11,1);
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INSERT INTO t2 VALUES (17,NULL);
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CREATE TABLE t1 (
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pk int(11) NOT NULL AUTO_INCREMENT,
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c1 int(11) DEFAULT NULL,
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PRIMARY KEY (pk));
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INSERT INTO t1 VALUES (15,1);
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INSERT INTO t1 VALUES (19,NULL);
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CREATE TABLE t3 (c2 int(11) DEFAULT NULL, KEY c2 (c2));
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INSERT INTO t3 VALUES (1);
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set @save_optimizer_switch=@@optimizer_switch;
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set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
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SELECT c2
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FROM t3
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WHERE (2, 6) IN (SELECT t1.c1, t1.c1 FROM t1 STRAIGHT_JOIN t2 ON t2.pk = t1.pk);
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c2
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set session optimizer_switch=@save_optimizer_switch;
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drop table t1, t2, t3;
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#
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# LP BUG#641245 Crash in Item_equal::contains
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#
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CREATE TABLE t1 (
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pk int(11) NOT NULL AUTO_INCREMENT,
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c1 int(11) DEFAULT NULL,
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c2 int(11) DEFAULT NULL,
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c3 varchar(1) DEFAULT NULL,
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c4 varchar(1) DEFAULT NULL,
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PRIMARY KEY (pk),
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KEY c2 (c2),
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KEY c3 (c3,c2));
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INSERT INTO t1 VALUES (10,7,8,'v','v');
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INSERT INTO t1 VALUES (11,1,9,'r','r');
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INSERT INTO t1 VALUES (12,5,9,'a','a');
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INSERT INTO t1 VALUES (13,7,18,'v','v');
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INSERT INTO t1 VALUES (14,1,19,'r','r');
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INSERT INTO t1 VALUES (15,5,29,'a','a');
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INSERT INTO t1 VALUES (17,7,38,'v','v');
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INSERT INTO t1 VALUES (18,1,39,'r','r');
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INSERT INTO t1 VALUES (19,5,49,'a','a');
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create table t1a like t1;
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insert into t1a select * from t1;
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create table t1b like t1;
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insert into t1b select * from t1;
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CREATE TABLE t2 (
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pk int(11) NOT NULL AUTO_INCREMENT,
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c1 int(11) DEFAULT NULL,
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c2 int(11) DEFAULT NULL,
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c3 varchar(1) DEFAULT NULL,
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c4 varchar(1) DEFAULT NULL,
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PRIMARY KEY (pk),
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KEY c2 (c2),
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KEY c3 (c3,c2));
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INSERT INTO t2 VALUES (1,NULL,2,'w','w');
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INSERT INTO t2 VALUES (2,7,9,'m','m');
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set @@optimizer_switch='materialization=off,in_to_exists=on,semijoin=off';
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EXPLAIN EXTENDED SELECT pk
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FROM t1
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WHERE c1 IN
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(SELECT t1a.c1
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FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
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t1a ON (t1a.c2 = t1b.pk AND 2)
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WHERE t1.pk) ;
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 9 100.00 Using where
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2 DEPENDENT SUBQUERY t1b ALL NULL NULL NULL NULL 9 100.00
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2 DEPENDENT SUBQUERY t1a ref c2 c2 5 test.t1b.pk 1 100.00 Using where
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2 DEPENDENT SUBQUERY t2 index c3 c3 9 NULL 2 100.00 Using where; Using index; Using join buffer (flat, BNL join)
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Warnings:
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Note 1276 Field or reference 'test.t1.pk' of SELECT #2 was resolved in SELECT #1
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Note 1003 select `test`.`t1`.`pk` AS `pk` from `test`.`t1` where <expr_cache><`test`.`t1`.`c1`,`test`.`t1`.`pk`>(<in_optimizer>(`test`.`t1`.`c1`,<exists>(select `test`.`t1a`.`c1` from `test`.`t1b` join `test`.`t2` left join `test`.`t1a` on((2 and (`test`.`t1a`.`c2` = `test`.`t1b`.`pk`))) where ((`test`.`t1`.`pk` <> 0) and (<cache>(`test`.`t1`.`c1`) = `test`.`t1a`.`c1`) and (`test`.`t2`.`c3` = `test`.`t1b`.`c4`)))))
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SELECT pk
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FROM t1
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WHERE c1 IN
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(SELECT t1a.c1
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FROM (t1b JOIN t2 ON t2.c3 = t1b.c4) LEFT JOIN
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t1a ON (t1a.c2 = t1b.pk AND 2)
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WHERE t1.pk) ;
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pk
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DROP TABLE t1, t1a, t1b, t2;
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#
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# LP BUG#714808 Assertion `outer_lookup_keys <= outer_record_count'
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# failed with materialization
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CREATE TABLE t1 ( pk int(11), PRIMARY KEY (pk)) ;
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CREATE TABLE t2 ( f2 int(11)) ;
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CREATE TABLE t3 ( f1 int(11), f3 varchar(1), KEY (f1)) ;
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INSERT INTO t3 VALUES (7,'f');
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set @@optimizer_switch='materialization=on,in_to_exists=on,semijoin=off';
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EXPLAIN
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SELECT t1.*
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FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
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WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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SELECT t1.*
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FROM t3 RIGHT JOIN t1 ON t1.pk = t3.f1
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WHERE t3.f3 OR ( 3 ) IN ( SELECT f2 FROM t2 );
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pk
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drop table t1,t2,t3;
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#
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# LP BUG#714999 Second crash in select_describe() with nested subqueries
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#
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CREATE TABLE t1 ( pk int(11)) ;
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INSERT INTO t1 VALUES (29);
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CREATE TABLE t2 ( f1 varchar(1)) ;
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INSERT INTO t2 VALUES ('f'),('d');
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CREATE TABLE t3 ( f2 varchar(1)) ;
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EXPLAIN SELECT f2 FROM t3 WHERE (
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SELECT MAX( pk ) FROM t1
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WHERE EXISTS (
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SELECT max(f1)
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FROM t2 GROUP BY f1
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)
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) IS NULL ;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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2 SUBQUERY t1 system NULL NULL NULL NULL 1
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3 SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using temporary; Using filesort
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drop table t1, t2, t3;
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#
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# LP BUG#715034 Item_sum_distinct::clear(): Assertion `tree != 0' failed
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#
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CREATE TABLE t2 ( f2 int(11)) ;
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CREATE TABLE t1 ( f3 int(11), KEY (f3)) ;
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INSERT INTO t1 VALUES (6),(4);
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set @tmp_optimizer_switch=@@optimizer_switch;
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set optimizer_switch='derived_merge=off,derived_with_keys=off';
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EXPLAIN
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SELECT * FROM (SELECT * FROM t2) AS a2
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WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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3 SUBQUERY t1 index NULL f3 5 NULL 2 Using index
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2 DERIVED NULL NULL NULL NULL NULL NULL NULL no matching row in const table
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insert into t2 values (1),(2);
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EXPLAIN
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SELECT * FROM (SELECT * FROM t2) AS a2
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WHERE (SELECT distinct SUM(distinct f3 ) FROM t1);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
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3 SUBQUERY t1 index NULL f3 5 NULL 2 Using index
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2 DERIVED t2 ALL NULL NULL NULL NULL 2
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set optimizer_switch=@tmp_optimizer_switch;
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drop table t1,t2;
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#
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# LP BUG#715027 Assertion `!table || (!table->read_set || bitmap_is_set(table->read_set, field_index))' failed
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#
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CREATE TABLE t1 ( f1 int(11), PRIMARY KEY (f1)) ;
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INSERT INTO t1 VALUES (28),(29);
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CREATE TABLE t2 ( f2 int(11), f3 int(11), f10 varchar(1)) ;
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INSERT INTO t2 VALUES (NULL,6,'f'),(4,2,'d');
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set @tmp_optimizer_switch=@@optimizer_switch;
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set optimizer_switch='derived_merge=off,derived_with_keys=off';
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EXPLAIN
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SELECT alias2.f2 AS field1
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FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
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WHERE (
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SELECT t2.f2
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FROM t2 JOIN t1 ON t1.f1
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WHERE t1.f1 AND alias2.f10
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)
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ORDER BY field1 ;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 Using where; Using filesort
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1 PRIMARY alias1 eq_ref PRIMARY PRIMARY 4 alias2.f3 1 Using index
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3 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2
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3 DEPENDENT SUBQUERY t1 index PRIMARY PRIMARY 4 NULL 2 Using where; Using index; Using join buffer (flat, BNL join)
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2 DERIVED t2 ALL NULL NULL NULL NULL 2
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SELECT alias2.f2 AS field1
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FROM t1 AS alias1 JOIN ( SELECT * FROM t2 ) AS alias2 ON alias2.f3 = alias1.f1
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WHERE (
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SELECT t2.f2
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FROM t2 JOIN t1 ON t1.f1
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WHERE t1.f1 AND alias2.f10
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)
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ORDER BY field1 ;
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field1
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set optimizer_switch=@tmp_optimizer_switch;
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drop table t1,t2;
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#
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# LP BUG#718578 Yet another Assertion `!table ||
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# (!table->read_set || bitmap_is_set(table->read_set, field_index))'
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CREATE TABLE t1 ( f1 int(11), f2 int(11), f3 int(11)) ;
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INSERT IGNORE INTO t1 VALUES (28,5,6),(29,NULL,4);
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CREATE TABLE t2 ( f10 varchar(1) );
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INSERT IGNORE INTO t2 VALUES (NULL);
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SELECT f1 AS field1
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FROM ( SELECT * FROM t1 ) AS alias1
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WHERE (SELECT t1.f1
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FROM t2 JOIN t1 ON t1.f2
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WHERE alias1.f3 AND t1.f3) AND f2
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ORDER BY field1;
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field1
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28
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drop table t1,t2;
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#
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# LP BUG#601124 Bug in eliminate_item_equal
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# leads to crash in Item_func::Item_func
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CREATE TABLE t1 ( f1 int(11), f3 varchar(1)) ;
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INSERT INTO t1 VALUES (5,'m'),(NULL,'c');
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CREATE TABLE t2 ( f2 int(11), f3 varchar(1)) ;
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INSERT INTO t2 VALUES (6,'f'),(2,'d');
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CREATE TABLE t3 ( f2 int(11), f3 varchar(1)) ;
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INSERT INTO t3 VALUES (6,'f'),(2,'d');
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SELECT * FROM t3
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WHERE ( f2 ) IN (SELECT t1.f1
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FROM t1 STRAIGHT_JOIN t2 ON t2.f3 = t1.f3
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WHERE t2.f3 = 'c');
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f2 f3
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drop table t1,t2,t3;
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#
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# LP BUG#718593 Crash in substitute_for_best_equal_field -> eliminate_item_equal ->
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# Item_field::find_item_equal -> Item_equal::contains
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#
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set @save_optimizer_switch=@@optimizer_switch;
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SET @@optimizer_switch = 'semijoin=off';
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CREATE TABLE t1 ( f3 int(11), f10 varchar(1), f11 varchar(1)) ;
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INSERT IGNORE INTO t1 VALUES (6,'f','f'),(2,'d','d');
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CREATE TABLE t2 ( f12 int(11), f13 int(11)) ;
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insert into t2 values (1,2), (3,4);
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EXPLAIN
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SELECT * FROM t2
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WHERE ( f12 ) IN (
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SELECT alias2.f3
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FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
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WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
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);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
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2 MATERIALIZED alias1 ALL NULL NULL NULL NULL 2 Using where
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2 MATERIALIZED alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
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SELECT * FROM t2
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WHERE ( f12 ) IN (
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SELECT alias2.f3
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FROM t1 AS alias1 JOIN t1 AS alias2 ON alias2.f10 = alias1.f11
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WHERE alias1.f11 OR alias1.f3 = 50 AND alias1.f10
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);
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f12 f13
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EXPLAIN
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SELECT * FROM t2
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WHERE ( f12 ) IN (
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SELECT alias2.f3
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FROM t1 AS alias1, t1 AS alias2
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WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Using where
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2 MATERIALIZED alias1 ALL NULL NULL NULL NULL 2 Using where
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2 MATERIALIZED alias2 ALL NULL NULL NULL NULL 2 Using where; Using join buffer (flat, BNL join)
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SELECT * FROM t2
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WHERE ( f12 ) IN (
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SELECT alias2.f3
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FROM t1 AS alias1, t1 AS alias2
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WHERE (alias2.f10 = alias1.f11) AND (alias1.f11 OR alias1.f3 = 50 AND alias1.f10));
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f12 f13
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set @@optimizer_switch=@save_optimizer_switch;
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drop table t1, t2;
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#
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# MWL#89: test introduced after Sergey Petrunia's review - test that
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# keyparts wihtout index prefix are used with the IN-EXISTS strategy.
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#
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create table t1 (c1 int);
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insert into t1 values (1), (2), (3);
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create table t2 (kp1 int, kp2 int, c2 int, filler char(100));
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insert into t2 values (0,0,0,'filler'),(0,1,1,'filler'),(0,2,2,'filler'),(0,3,3,'filler');
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create index key1 on t2 (kp1, kp2);
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create index key2 on t2 (kp1);
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create index key3 on t2 (kp2);
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SET @@optimizer_switch='materialization=off,semijoin=off,in_to_exists=on';
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analyze table t2;
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Table Op Msg_type Msg_text
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test.t2 analyze status OK
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explain
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select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where
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2 DEPENDENT SUBQUERY t2 index_subquery key1,key2,key3 key1 10 func,const 1 Using where
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select c1 from t1 where c1 in (select kp1 from t2 where kp2 = 10 and c2 = 4) or c1 > 7;
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c1
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set @@optimizer_switch='default';
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drop table t1, t2;
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#
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# LP BUG#800679: Assertion `outer_join->table_count > 0' failed in
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# JOIN::choose_subquery_plan() with materialization=on,semijoin=off
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#
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CREATE TABLE t1 ( f1 int);
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insert into t1 values (1),(2);
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CREATE TABLE t2 ( f1 int);
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insert into t2 values (1),(2);
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SET @@optimizer_switch='materialization=on,semijoin=off';
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EXPLAIN
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SELECT * FROM t1
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WHERE (f1) IN (SELECT f1 FROM t2)
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LIMIT 0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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2 DEPENDENT SUBQUERY t2 ALL NULL NULL NULL NULL 2 Using where
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SELECT * FROM t1
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WHERE (f1) IN (SELECT f1 FROM t2)
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LIMIT 0;
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f1
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set @@optimizer_switch='default';
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drop table t1, t2;
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#
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# LP BUG#834492: Crash in fix_semijoin_strategies_for_picked_join_order
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# with nested subqueries and LooseScan=ON
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#
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CREATE TABLE t3 (b int) ;
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INSERT INTO t3 VALUES (0),(0);
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CREATE TABLE t4 (a int, b int, c int, d int, PRIMARY KEY (a)) ;
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INSERT INTO t4 VALUES (28,0,0,0),(29,3,0,0);
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CREATE TABLE t5 (a int, b int, c int, d int, KEY (c,b)) ;
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INSERT INTO t5 VALUES (28,0,0,0),(29,3,0,0);
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SET @@optimizer_switch='semijoin=ON,loosescan=ON,firstmatch=OFF,materialization=OFF';
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EXPLAIN SELECT *
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FROM t3
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WHERE t3.b > ALL (
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SELECT c
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FROM t4
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WHERE t4.a >= t3.b
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AND a = SOME (SELECT b FROM t5));
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t3 ALL NULL NULL NULL NULL 2 Using where
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2 DEPENDENT SUBQUERY t5 index c c 10 NULL 2 Using where; Using index; Start temporary
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2 DEPENDENT SUBQUERY t4 eq_ref PRIMARY PRIMARY 4 test.t5.b 1 Using index condition; Using where; End temporary
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SELECT *
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FROM t3
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WHERE t3.b > ALL (
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SELECT c
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FROM t4
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WHERE t4.a >= t3.b
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AND a = SOME (SELECT b FROM t5));
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b
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0
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0
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set @@optimizer_switch='default';
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drop table t3, t4, t5;
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#
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# LP BUG#858038 The result of a query with NOT IN subquery depends on the state of the optimizer switch
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#
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create table t1 (c1 char(2) not null, c2 char(2));
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create table t2 (c3 char(2), c4 char(2));
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insert into t1 values ('a1', 'b1');
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insert into t1 values ('a2', 'b2');
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insert into t2 values ('x1', 'y1');
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insert into t2 values ('a2', null);
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set @@optimizer_switch='in_to_exists=off,materialization=on,partial_match_rowid_merge=off,partial_match_table_scan=on';
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explain select * from t1 where c1 = 'a2' and (c1, c2) not in (select * from t2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
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2 MATERIALIZED t2 ALL NULL NULL NULL NULL 2
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select * from t1 where c1 = 'a2' and (c1, c2) not in (select * from t2);
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c1 c2
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set @@optimizer_switch='in_to_exists=off,materialization=on,partial_match_rowid_merge=on,partial_match_table_scan=off';
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explain select * from t1 where c1 = 'a2' and (c1, c2) not in (select * from t2);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 2 Using where
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2 MATERIALIZED t2 ALL NULL NULL NULL NULL 2
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select * from t1 where c1 = 'a2' and (c1, c2) not in (select * from t2);
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c1 c2
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drop table t1, t2;
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