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ChangeSet@1.2536.50.1  2007-08-02 12:45:56-07:00  igor@mysql.com

Fixed bug#28404.
This patch adds cost estimation for the queries with ORDER BY / GROUP BY
and LIMIT.
If there was a ref/range access to the table whose rows were required
to be ordered in the result set the optimizer always employed this access
though a scan by a different index that was compatible with the required
order could be cheaper to produce the first L rows of the result set.
Now for such queries the optimizer makes a choice between the cheapest
ref/range accesses not compatible with the given order and index scans
compatible with it.

innodb.result: Adjusted results for test cases affected fy the fix for
bug #28404.
This commit is contained in:
sunny 2007-09-07 00:04:10 +00:00
parent aaf0c55719
commit 02d91af9e7
1 changed files with 1 additions and 1 deletions
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mysql-test/innodb.result
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@ -948,7 +948,7 @@ id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL PRIMARY 4 NULL #
explain select * from t1 order by b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL b 4 NULL #
1 SIMPLE t1 ALL NULL NULL NULL NULL # Using filesort
explain select * from t1 order by c;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 ALL NULL NULL NULL NULL # Using filesort