database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-09-02 09:41:40 +03:00
Code Activity

Fixed bug#35844.

Browse Source 
The function test_if_skip_sort_order ignored any covering index used for ref
access of a table in a query with ORDER BY if this index was incompatible 
with the ORDER BY list and there was another covering index compatible with
this list. 
As a result sub-optimal execution plans were chosen for some queries with
ORDER BY clause.
This commit is contained in:
igor@olga.mysql.com
2008-04-22 21:49:39 -07:00
parent 013fd23675
commit b210e5df6d
4 changed files with 65 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
mysql-test/r/distinct.result
View File

@@ -694,7 +694,7 @@ INSERT INTO t1(a, b, c) VALUES (1, 1, 1),
(1, 2, 3);
EXPLAIN SELECT DISTINCT a, b, d, c FROM t1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index NULL a 16 NULL 6 Using index
1 SIMPLE t1 range NULL PRIMARY 16 NULL 7 Using index for group-by; Using temporary
SELECT DISTINCT a, b, d, c FROM t1;
a b d c
1 1 0 1