70 lines
2.5 KiB
Plaintext
70 lines
2.5 KiB
Plaintext
drop table if exists t0,t1,t2,t3;
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#
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# BUG#38049 incorrect rows estimations with references from preceding table
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#
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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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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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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE a ALL NULL NULL NULL NULL 2 Using where
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1 SIMPLE g ref groups_dt groups_dt 70 const,test.a.type 13 Using index condition
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drop table t0,t1,t2,t3;
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#
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# BUG#47217 Lost optimization caused slowdown & wrong result.
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#
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CREATE TABLE t1 (pk INT, v VARCHAR(2), PRIMARY KEY(pk));
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CREATE INDEX ix1 ON t1(v);
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CREATE TABLE t2 (pk INT, v VARCHAR(2), PRIMARY KEY(pk));
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CREATE INDEX ix2 ON t2(v);
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INSERT INTO t1 VALUES (1,'a'),(2,NULL);
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INSERT INTO t2 VALUES (1,NULL);
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EXPLAIN SELECT * FROM t1 JOIN t2 ON t1.v = t2.v ORDER BY 1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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EXPLAIN SELECT * FROM t1 JOIN t2 ON t1.v = t2.v;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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INSERT INTO t1 VALUES (3,'b'),(4,NULL),(5,'c'),(6,'cc'),(7,'d'),
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(8,'dd'),(9,'e'),(10,'ee');
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INSERT INTO t2 VALUES (2,NULL);
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FLUSH STATUS;
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SELECT * FROM t1 JOIN t2 ON t1.v = t2.v WHERE t2.v IS NULL ORDER BY 1;
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pk v pk v
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SHOW STATUS LIKE 'Handler_read_%';
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Variable_name Value
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Handler_read_first 0
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Handler_read_key 1
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Handler_read_last 0
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Handler_read_next 0
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Handler_read_prev 0
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Handler_read_rnd 0
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Handler_read_rnd_next 1
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DROP TABLE t1, t2;
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# End of test for bug#47217
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