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BUG#38049 "incorrect rows estimations with references from preceding table" (from revid:sergefp@mysql.com-20090126194259-ue20il3qro529l4d). Compared to 6.0 where EXPLAIN indicates "Using index condition", here in join_optimizer.result we see "Using where"; it's normal; 6.0 shows the same if disabling Index Condition Pushdown.
45 lines
1.3 KiB
Text
45 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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--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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