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Range optimizer fix:

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If cost(full_scan_on_shortest_covering_index) < cost(best_range_scan) <  cost(full_table_scan)
  use full_scan_on_shortest_covering_index
(before this fix best_range_scan was used)
This commit is contained in:
sergefp@mysql.com
2004-06-22 04:47:28 +04:00
parent 7a9f4c6a2a
commit f874071a26
14 changed files with 36 additions and 36 deletions
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4
mysql-test/r/derived.result
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@ -318,11 +318,11 @@ create table t2 (a int, b int, primary key (a));
insert into t2 values (1,7),(2,7);
explain select a from t2 where a>1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 range PRIMARY PRIMARY 4 NULL 2 Using where; Using index
1 SIMPLE t2 index PRIMARY PRIMARY 4 NULL 2 Using where; Using index
explain select a from (select a from t2 where a>1) tt;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> system NULL NULL NULL NULL 1
2 DERIVED t2 range PRIMARY PRIMARY 4 NULL 2 Using where; Using index
2 DERIVED t2 index PRIMARY PRIMARY 4 NULL 2 Using where; Using index
drop table t2;
CREATE TABLE `t1` ( `itemid` int(11) NOT NULL default '0', `grpid` varchar(15) NOT NULL default '', `vendor` int(11) NOT NULL default '0', `date_` date NOT NULL default '0000-00-00', `price` decimal(12,2) NOT NULL default '0.00', PRIMARY KEY (`itemid`,`grpid`,`vendor`,`date_`), KEY `itemid` (`itemid`,`vendor`), KEY `itemid_2` (`itemid`,`date_`));
insert into t1 values (128, 'rozn', 2, now(), 10),(128, 'rozn', 1, now(), 10);