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Message #09597
Re: [Commits] b1ddc7d: MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops with UNION in ALL subquery
Hi Sanja, Sergey,
I think Sergey might have mean the same thing but it is not clear to me.
in_optimize never gets set to true. By mentioning that it is redundant that
means that it can be removed from the current code right?
Also, I would put the "return true" conditions after the "return false"
conditions. Makes the code slightly easier to follow.
Vicentiu
On Wed, 4 May 2016 at 18:59 Sergey Petrunia <sergey@xxxxxxxxxxx> wrote:
> Hi Sanja,
>
> I have one comment: the patch introduces JOIN::in_optimize which can have
> values of 1) not initialized and 2) false. This is clearly redundant.
>
> Ok to push after the above is addressed.
>
> On Sun, Feb 21, 2016 at 10:12:25PM +0100, OleksandrByelkin wrote:
> > revision-id: b1ddc7d546e6b147838af72dd03f86a8b272fdf0
> (mariadb-10.1.11-18-gb1ddc7d)
> > parent(s): fd8e846a3b049903706267d58e6d8e61eea97df8
> > committer: Oleksandr Byelkin
> > timestamp: 2016-02-21 22:12:25 +0100
> > message:
> >
> > MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops with
> UNION in ALL subquery
> >
> > Do not mark subquery as inexpensive when it is not optimized.
> >
> > ---
> > mysql-test/r/derived_view.result | 6 +++---
> > mysql-test/r/subselect.result | 20 +++++++++++++++++---
> > mysql-test/r/subselect_no_exists_to_in.result | 20 +++++++++++++++++---
> > mysql-test/r/subselect_no_mat.result | 20 +++++++++++++++++---
> > mysql-test/r/subselect_no_opts.result | 20 +++++++++++++++++---
> > mysql-test/r/subselect_no_scache.result | 20 +++++++++++++++++---
> > mysql-test/r/subselect_no_semijoin.result | 20 +++++++++++++++++---
> > mysql-test/r/type_year.result | 1 +
> > mysql-test/t/subselect.test | 11 +++++++++++
> > sql/item_subselect.cc | 20 ++++++++++++++++----
> > sql/sql_select.h | 2 ++
> > 11 files changed, 135 insertions(+), 25 deletions(-)
> >
> > diff --git a/mysql-test/r/derived_view.result
> b/mysql-test/r/derived_view.result
> > index 639942f..5783247 100644
> > --- a/mysql-test/r/derived_view.result
> > +++ b/mysql-test/r/derived_view.result
> > @@ -1101,7 +1101,7 @@ id select_type table type
> possible_keys key key_len ref rows filtered Extra
> > 1 PRIMARY t3 system NULL NULL NULL NULL 1
> 100.00
> > 2 SUBQUERY NULL NULL NULL NULL NULL NULL
> NULL NULL No tables used
> > Warnings:
> > -Note 1003 select 6 AS `a`,5 AS `b` from `test`.`t3` where
> (not(<expr_cache><6,5>(<in_optimizer>((6,5),<exists>(select 7,5 having
> (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5)
> or isnull(5))) and trigcond(<is_not_null_test>(7)) and
> trigcond(<is_not_null_test>(5))))))))
> > +Note 1003 select 6 AS `a`,5 AS `b` from `test`.`t3` where 1
> > SELECT t.a,t.b FROM t3 RIGHT JOIN ((SELECT * FROM t1) AS t, t2) ON t2.b
> != 0
> > WHERE (t.a,t.b) NOT IN (SELECT 7, 5);
> > a b
> > @@ -1115,7 +1115,7 @@ id select_type table type
> possible_keys key key_len ref rows filtered Extra
> > 1 PRIMARY t3 system NULL NULL NULL NULL 1
> 100.00
> > 3 SUBQUERY NULL NULL NULL NULL NULL NULL
> NULL NULL No tables used
> > Warnings:
> > -Note 1003 select 6 AS `a`,5 AS `b` from `test`.`t3` where
> (not(<expr_cache><6,5>(<in_optimizer>((6,5),<exists>(select 7,5 having
> (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5)
> or isnull(5))) and trigcond(<is_not_null_test>(7)) and
> trigcond(<is_not_null_test>(5))))))))
> > +Note 1003 select 6 AS `a`,5 AS `b` from `test`.`t3` where 1
> > SELECT t.a,t.b FROM t3 RIGHT JOIN (v1 AS t, t2) ON t2.b != 0
> > WHERE (t.a,t.b) NOT IN (SELECT 7, 5);
> > a b
> > @@ -1129,7 +1129,7 @@ id select_type table type
> possible_keys key key_len ref rows filtered Extra
> > 1 PRIMARY t3 system NULL NULL NULL NULL 1
> 100.00
> > 2 SUBQUERY NULL NULL NULL NULL NULL NULL
> NULL NULL No tables used
> > Warnings:
> > -Note 1003 select 6 AS `a`,5 AS `b` from `test`.`t3` where
> (not(<expr_cache><6,5>(<in_optimizer>((6,5),<exists>(select 7,5 having
> (trigcond(((<cache>(6) = 7) or isnull(7))) and trigcond(((<cache>(5) = 5)
> or isnull(5))) and trigcond(<is_not_null_test>(7)) and
> trigcond(<is_not_null_test>(5))))))))
> > +Note 1003 select 6 AS `a`,5 AS `b` from `test`.`t3` where 1
> > DROP VIEW v1;
> > DROP TABLE t1,t2,t3;
> > #
> > diff --git a/mysql-test/r/subselect.result
> b/mysql-test/r/subselect.result
> > index 75c8597..90d8f9f 100644
> > --- a/mysql-test/r/subselect.result
> > +++ b/mysql-test/r/subselect.result
> > @@ -6805,7 +6805,9 @@ FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR alias1.a = 'y'
> > HAVING field>'B' AND ( 'Moscow' ) IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY NULL NULL NULL NULL NULL NULL NULL
> Impossible HAVING
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > +1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a ) AS field
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > @@ -6817,8 +6819,8 @@ SELECT MAX( alias2.a )
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR ('Moscow') IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY alias1 index a a 19 NULL 11
> Using where; Using index
> > -1 PRIMARY alias2 ref a a 19 test.alias1.a 2
> Using index
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > 1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a )
> > @@ -7133,3 +7135,15 @@ sq
> > NULL
> > drop view v2;
> > drop table t1,t2;
> > +#
> > +# MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops
> > +# with UNION in ALL subquery
> > +#
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +f
> > +foo
> > +drop table t1;
> > +SET NAMES default;
> > diff --git a/mysql-test/r/subselect_no_exists_to_in.result
> b/mysql-test/r/subselect_no_exists_to_in.result
> > index e6238af..dcceb61 100644
> > --- a/mysql-test/r/subselect_no_exists_to_in.result
> > +++ b/mysql-test/r/subselect_no_exists_to_in.result
> > @@ -6805,7 +6805,9 @@ FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR alias1.a = 'y'
> > HAVING field>'B' AND ( 'Moscow' ) IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY NULL NULL NULL NULL NULL NULL NULL
> Impossible HAVING
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > +1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a ) AS field
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > @@ -6817,8 +6819,8 @@ SELECT MAX( alias2.a )
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR ('Moscow') IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY alias1 index a a 19 NULL 11
> Using where; Using index
> > -1 PRIMARY alias2 ref a a 19 test.alias1.a 2
> Using index
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > 1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a )
> > @@ -7133,6 +7135,18 @@ sq
> > NULL
> > drop view v2;
> > drop table t1,t2;
> > +#
> > +# MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops
> > +# with UNION in ALL subquery
> > +#
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +f
> > +foo
> > +drop table t1;
> > +SET NAMES default;
> > set optimizer_switch=default;
> > select @@optimizer_switch like '%exists_to_in=off%';
> > @@optimizer_switch like '%exists_to_in=off%'
> > diff --git a/mysql-test/r/subselect_no_mat.result
> b/mysql-test/r/subselect_no_mat.result
> > index 70edc64..4e9f750 100644
> > --- a/mysql-test/r/subselect_no_mat.result
> > +++ b/mysql-test/r/subselect_no_mat.result
> > @@ -6800,7 +6800,9 @@ FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR alias1.a = 'y'
> > HAVING field>'B' AND ( 'Moscow' ) IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY NULL NULL NULL NULL NULL NULL NULL
> Impossible HAVING
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > +1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a ) AS field
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > @@ -6812,8 +6814,8 @@ SELECT MAX( alias2.a )
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR ('Moscow') IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY alias1 index a a 19 NULL 11
> Using where; Using index
> > -1 PRIMARY alias2 ref a a 19 test.alias1.a 2
> Using index
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > 1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a )
> > @@ -7126,6 +7128,18 @@ sq
> > NULL
> > drop view v2;
> > drop table t1,t2;
> > +#
> > +# MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops
> > +# with UNION in ALL subquery
> > +#
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +f
> > +foo
> > +drop table t1;
> > +SET NAMES default;
> > set optimizer_switch=default;
> > select @@optimizer_switch like '%materialization=on%';
> > @@optimizer_switch like '%materialization=on%'
> > diff --git a/mysql-test/r/subselect_no_opts.result
> b/mysql-test/r/subselect_no_opts.result
> > index c89fd13..4b09fd2 100644
> > --- a/mysql-test/r/subselect_no_opts.result
> > +++ b/mysql-test/r/subselect_no_opts.result
> > @@ -6796,7 +6796,9 @@ FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR alias1.a = 'y'
> > HAVING field>'B' AND ( 'Moscow' ) IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY NULL NULL NULL NULL NULL NULL NULL
> Impossible HAVING
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > +1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a ) AS field
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > @@ -6808,8 +6810,8 @@ SELECT MAX( alias2.a )
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR ('Moscow') IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY alias1 index a a 19 NULL 11
> Using where; Using index
> > -1 PRIMARY alias2 ref a a 19 test.alias1.a 2
> Using index
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > 1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a )
> > @@ -7124,4 +7126,16 @@ sq
> > NULL
> > drop view v2;
> > drop table t1,t2;
> > +#
> > +# MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops
> > +# with UNION in ALL subquery
> > +#
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +f
> > +foo
> > +drop table t1;
> > +SET NAMES default;
> > set @optimizer_switch_for_subselect_test=null;
> > diff --git a/mysql-test/r/subselect_no_scache.result
> b/mysql-test/r/subselect_no_scache.result
> > index b12bf21..322e64d 100644
> > --- a/mysql-test/r/subselect_no_scache.result
> > +++ b/mysql-test/r/subselect_no_scache.result
> > @@ -6811,7 +6811,9 @@ FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR alias1.a = 'y'
> > HAVING field>'B' AND ( 'Moscow' ) IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY NULL NULL NULL NULL NULL NULL NULL
> Impossible HAVING
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > +1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a ) AS field
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > @@ -6823,8 +6825,8 @@ SELECT MAX( alias2.a )
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR ('Moscow') IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY alias1 index a a 19 NULL 11
> Using where; Using index
> > -1 PRIMARY alias2 ref a a 19 test.alias1.a 2
> Using index
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > 1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a )
> > @@ -7139,6 +7141,18 @@ sq
> > NULL
> > drop view v2;
> > drop table t1,t2;
> > +#
> > +# MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops
> > +# with UNION in ALL subquery
> > +#
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +f
> > +foo
> > +drop table t1;
> > +SET NAMES default;
> > set optimizer_switch=default;
> > select @@optimizer_switch like '%subquery_cache=on%';
> > @@optimizer_switch like '%subquery_cache=on%'
> > diff --git a/mysql-test/r/subselect_no_semijoin.result
> b/mysql-test/r/subselect_no_semijoin.result
> > index 54f145d..d380528 100644
> > --- a/mysql-test/r/subselect_no_semijoin.result
> > +++ b/mysql-test/r/subselect_no_semijoin.result
> > @@ -6796,7 +6796,9 @@ FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR alias1.a = 'y'
> > HAVING field>'B' AND ( 'Moscow' ) IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY NULL NULL NULL NULL NULL NULL NULL
> Impossible HAVING
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > +1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a ) AS field
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > @@ -6808,8 +6810,8 @@ SELECT MAX( alias2.a )
> > FROM t1 AS alias1, t1 AS alias2, t1 AS alias3
> > WHERE alias1.a = alias2.a OR ('Moscow') IN ( SELECT a FROM t1 );
> > id select_type table type possible_keys key key_len
> ref rows Extra
> > -1 PRIMARY alias1 index a a 19 NULL 11
> Using where; Using index
> > -1 PRIMARY alias2 ref a a 19 test.alias1.a 2
> Using index
> > +1 PRIMARY alias1 index a a 19 NULL 11
> Using index
> > +1 PRIMARY alias2 index a a 19 NULL 11
> Using where; Using index; Using join buffer (flat, BNL join)
> > 1 PRIMARY alias3 index NULL a 19 NULL 11
> Using index; Using join buffer (flat, BNL join)
> > 2 SUBQUERY t1 index_subquery a a 19
> const 1 Using index; Using where
> > SELECT MAX( alias2.a )
> > @@ -7124,5 +7126,17 @@ sq
> > NULL
> > drop view v2;
> > drop table t1,t2;
> > +#
> > +# MDEV-9487: Server crashes in Time_and_counter_tracker::incr_loops
> > +# with UNION in ALL subquery
> > +#
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +f
> > +foo
> > +drop table t1;
> > +SET NAMES default;
> > set @optimizer_switch_for_subselect_test=null;
> > set @join_cache_level_for_subselect_test=NULL;
> > diff --git a/mysql-test/r/type_year.result
> b/mysql-test/r/type_year.result
> > index 842a16e..204cec2 100644
> > --- a/mysql-test/r/type_year.result
> > +++ b/mysql-test/r/type_year.result
> > @@ -387,6 +387,7 @@ a
> > 00
> > select a from t1 where a=(select 2000 from dual where 1);
> > a
> > +00
> > select a from t1 where a=y2k();
> > a
> > 00
> > diff --git a/mysql-test/t/subselect.test b/mysql-test/t/subselect.test
> > index a862870..f71c215 100644
> > --- a/mysql-test/t/subselect.test
> > +++ b/mysql-test/t/subselect.test
> > @@ -5989,3 +5989,14 @@ SELECT ( SELECT MIN(v2.f2) FROM t1 ) AS sq FROM
> v2 GROUP BY sq;
> >
> > drop view v2;
> > drop table t1,t2;
> > +
> > +--echo #
> > +--echo # MDEV-9487: Server crashes in
> Time_and_counter_tracker::incr_loops
> > +--echo # with UNION in ALL subquery
> > +--echo #
> > +SET NAMES utf8;
> > +CREATE TABLE t1 (f VARCHAR(8)) ENGINE=MyISAM;
> > +INSERT INTO t1 VALUES ('foo');
> > +SELECT f FROM t1 WHERE f > ALL ( SELECT 'bar' UNION SELECT 'baz' );
> > +drop table t1;
> > +SET NAMES default;
> > diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
> > index d4e3e6c..f45d83d 100644
> > --- a/sql/item_subselect.cc
> > +++ b/sql/item_subselect.cc
> > @@ -561,22 +561,34 @@ bool Item_subselect::is_expensive()
> > for (SELECT_LEX *sl= unit->first_select(); sl; sl= sl->next_select())
> > {
> > JOIN *cur_join= sl->join;
> > +
> > + /* not optimized subquery */
> > if (!cur_join)
> > - continue;
> > + return true;
> > +
> > + /* very simple subquery */
> > + if (!cur_join->tables_list && !sl->first_inner_unit())
> > + return false;
> > +
> > + /*
> > + If the subquery is not optimised or in the process of optimization
> > + it supposed to be expensive
> > + */
> > + if (!cur_join->optimized || cur_join->in_optimize)
> > + return true;
> >
> > /*
> > Subqueries whose result is known after optimization are not
> expensive.
> > Such subqueries have all tables optimized away, thus have no join
> plan.
> > */
> > - if (cur_join->optimized &&
> > - (cur_join->zero_result_cause || !cur_join->tables_list))
> > + if ((cur_join->zero_result_cause || !cur_join->tables_list))
> > return false;
> >
> > /*
> > If a subquery is not optimized we cannot estimate its cost. A
> subquery is
> > considered optimized if it has a join plan.
> > */
> > - if (!(cur_join->optimized && cur_join->join_tab))
> > + if (!cur_join->join_tab)
> > return true;
> >
> > if (sl->first_inner_unit())
> > diff --git a/sql/sql_select.h b/sql/sql_select.h
> > index 9f90473..e57844fd 100644
> > --- a/sql/sql_select.h
> > +++ b/sql/sql_select.h
> > @@ -1292,6 +1292,7 @@ class JOIN :public Sql_alloc
> > OPTIMIZATION_IN_PROGRESS=1,
> > OPTIMIZATION_DONE=2};
> > bool optimized; ///< flag to avoid double optimization in EXPLAIN
> > + bool in_optimize;
> > bool initialized; ///< flag to avoid double init_execution calls
> >
> > Explain_select *explain;
> > @@ -1380,6 +1381,7 @@ class JOIN :public Sql_alloc
> > ref_pointer_array_size= 0;
> > zero_result_cause= 0;
> > optimized= 0;
> > + in_optimize= 0;
> > have_query_plan= QEP_NOT_PRESENT_YET;
> > initialized= 0;
> > cleaned= 0;
>
> BR
> Sergei
> --
> Sergei Petrunia, Software Developer
> MariaDB Corporation | Skype: sergefp | Blog: http://s.petrunia.net/blog
>
>
>
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