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merge::records_in_range and optimizer

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sql/sql_select.cc:
  optimizer bug fixed. (what's the difference between s->records ans s->found_records ?)
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unknown
2002-11-17 18:58:03 +01:00
parent 564c7b241f
commit 4589844513
3 changed files with 72 additions and 4 deletions
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39
mysql-test/r/merge.result
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@ -35,10 +35,10 @@ insert into t1 select NULL,message from t2;
create table t3 (a int not null, b char(20), key(a)) type=MERGE UNION=(test.t1,test.t2);
explain select * from t3 where a < 10;
table type possible_keys key key_len ref rows Extra
t3 range a a 4 NULL 10 Using where
t3 range a a 4 NULL 18 Using where
explain select * from t3 where a > 10 and a < 20;
table type possible_keys key key_len ref rows Extra
t3 range a a 4 NULL 10 Using where
t3 range a a 4 NULL 16 Using where
select * from t3 where a = 10;
a b
10 Testing
@ -561,3 +561,38 @@ a
1
2
drop table if exists t1, t2, t3, t4, t5, t6;
DROP TABLE IF EXISTS t1, t2;
CREATE TABLE t1 (
fileset_id tinyint(3) unsigned NOT NULL default '0',
file_code varchar(32) NOT NULL default '',
fileset_root_id tinyint(3) unsigned NOT NULL default '0',
PRIMARY KEY (fileset_id,file_code),
KEY files (fileset_id,fileset_root_id)
) TYPE=MyISAM;
INSERT INTO t1 VALUES (2, '0000000111', 1), (2, '0000000112', 1), (2, '0000000113', 1),
(2, '0000000114', 1), (2, '0000000115', 1), (2, '0000000116', 1), (2, '0000000117', 1),
(2, '0000000118', 1), (2, '0000000119', 1), (2, '0000000120', 1);
CREATE TABLE t2 (
fileset_id tinyint(3) unsigned NOT NULL default '0',
file_code varchar(32) NOT NULL default '',
fileset_root_id tinyint(3) unsigned NOT NULL default '0',
PRIMARY KEY (fileset_id,file_code),
KEY files (fileset_id,fileset_root_id)
) TYPE=MRG_MyISAM UNION=(t1);
EXPLAIN SELECT * FROM t2 IGNORE INDEX (files) WHERE fileset_id = 2
AND file_code BETWEEN '0000000115' AND '0000000120' LIMIT 1;
table type possible_keys key key_len ref rows Extra
t2 range PRIMARY PRIMARY 33 NULL 5 Using where
EXPLAIN SELECT * FROM t2 WHERE fileset_id = 2
AND file_code BETWEEN '0000000115' AND '0000000120' LIMIT 1;
table type possible_keys key key_len ref rows Extra
t2 range PRIMARY,files PRIMARY 33 NULL 5 Using where
EXPLAIN SELECT * FROM t1 WHERE fileset_id = 2
AND file_code BETWEEN '0000000115' AND '0000000120' LIMIT 1;
table type possible_keys key key_len ref rows Extra
t1 range PRIMARY,files PRIMARY 33 NULL 5 Using where
EXPLAIN SELECT * FROM t2 WHERE fileset_id = 2
AND file_code = '0000000115' LIMIT 1;
table type possible_keys key key_len ref rows Extra
t2 const PRIMARY,files PRIMARY 33 const,const 1
DROP TABLE IF EXISTS t1, t2;