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08a4732860
The problem was that join_buffer_size conflicted with join_buffer_space_limit, which caused the query to be run without join buffer. However this caused wrong results as the optimizer assumed that hash+join buffer would ensure that the equi-join condition would be satisfied, and didn't check it itself. Fixed by not using join_buffer_space_limit when optimize_join_buffer_size=off. This matches the documentation at https://mariadb.com/kb/en/block-based-join-algorithms Other things: - Removed not used variable JOIN_TAB::join_buffer_size_limit - Give an error if we cannot allocate a join buffer. This can only happen if the join_buffer variables are wrongly configured or we are running out of memory. In the future, instead of returning an error, we could properly convert the query plan that uses BNL-H join into one that doesn't use join buffering: make sure the equi-join condition is checked where appropriate. Reviewer: Sergei Petrunia <sergey@mariadb.com>
47 lines
1.3 KiB
Text
47 lines
1.3 KiB
Text
--disable_warnings
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drop table if exists t0,t1,t2,t3;
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--enable_warnings
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--source include/have_innodb.inc
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--echo #
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--echo # BUG#38049 incorrect rows estimations with references from preceding table
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--echo #
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create table t0 (a int);
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insert into t0 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
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create table t1 (a varchar(32));
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insert into t1 values ('owner'),('requester'),('admincc'),('cc');
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CREATE TABLE t2 (
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id int(11) NOT NULL,
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type varchar(32) default NULL,
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PRIMARY KEY (id)
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);
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insert into t2 values (1,'owner'), (2,'admincc');
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CREATE TABLE t3 (
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id int(11) NOT NULL,
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domain varchar(32) default NULL,
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type varchar(32) default NULL,
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PRIMARY KEY (id)
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);
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set @domain='system';
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set @pk=0;
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INSERT INTO t3 select @pk:=@pk+1, 'system', t1.a from t1;
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INSERT INTO t3 select @pk:=@pk+1, 'queue', t1.a from t1, t0 where t0.a<3;
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INSERT INTO t3 select @pk:=@pk+1, 'ticket', t1.a from t1, t0 A, t0 B, t0 C;
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CREATE INDEX groups_d ON t3(domain);
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CREATE INDEX groups_t ON t3(type);
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CREATE INDEX groups_td ON t3(type, domain);
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CREATE INDEX groups_dt ON t3(domain, type);
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--echo For table g this must use ref(groups_dt) and #rows should be around 15 and not 335:
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explain
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SELECT STRAIGHT_JOIN g.id FROM t2 a, t3 g USE INDEX(groups_dt)
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WHERE g.domain = 'queue' AND g.type = a.type;
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drop table t0,t1,t2,t3;
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