mirror/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2026-05-15 11:27:39 +02:00
Code Issues Projects Releases Packages Wiki Activity

Bug #43029: FORCE INDEX FOR ORDER BY is ignored when join

Browse source 
buffering is used

FORCE INDEX FOR ORDER BY now prevents the optimizer from 
using join buffering. As a result the optimizer can use
indexed access on the first table and doesn't need to 
sort the complete resultset at the end of the statement.
This commit is contained in:
Georgi Kodinov 2009-10-07 18:03:42 +03:00
commit 1a48dd4e2b
8 changed files with 116 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

32
mysql-test/t/order_by.test
View file

@ -1402,3 +1402,35 @@ SELECT DISTINCT a FROM t1 WHERE b = 1 ORDER BY c DESC LIMIT 0, 9;
SELECT DISTINCT a FROM t1 WHERE b = 1 ORDER BY c DESC LIMIT 0, 9;
DROP TABLE t1;
--echo #
--echo # Bug #43029: FORCE INDEX FOR ORDER BY is ignored when join buffering
--echo # is used
--echo #
CREATE TABLE t1 (a INT, b INT, KEY (a));
INSERT INTO t1 VALUES (0, NULL), (1, NULL), (2, NULL), (3, NULL);
INSERT INTO t1 SELECT a+4, b FROM t1;
INSERT INTO t1 SELECT a+8, b FROM t1;
CREATE TABLE t2 (a INT, b INT);
INSERT INTO t2 VALUES (0,NULL), (1,NULL), (2,NULL), (3,NULL), (4,NULL);
INSERT INTO t2 SELECT a+4, b FROM t2;
--echo # shouldn't have "using filesort"
EXPLAIN
SELECT * FROM t1 FORCE INDEX FOR ORDER BY (a), t2 WHERE t1.a < 2 ORDER BY t1.a;
--echo # should have "using filesort"
EXPLAIN
SELECT * FROM t1 USE INDEX FOR ORDER BY (a), t2 WHERE t1.a < 2 ORDER BY t1.a;
--echo # should have "using filesort"
EXPLAIN
SELECT * FROM t1 FORCE INDEX FOR JOIN (a), t2 WHERE t1.a < 2 ORDER BY t1.a;
DROP TABLE t1, t2;
--echo End of 5.1 tests