From: Date: May 12 2006 4:47am Subject: bk commit into 5.0 tree (igor:1.2126) BUG#18940 List-Archive: http://lists.mysql.com/commits/6273 X-Bug: 18940 Message-Id: <20060512024712.CDE532C872D@rurik.mysql.com> Below is the list of changes that have just been committed into a local 5.0 repository of igor. When igor does a push these changes will be propagated to the main repository and, within 24 hours after the push, to the public repository. For information on how to access the public repository see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html ChangeSet 1.2126 06/05/11 19:47:00 igor@stripped +2 -0 Added a test case for bug #18940:in 5.0 the optimizer chose a worse execution plan than in 4.1 for some queries. It happened due the fact that at some conditions the optimizer always preferred range or full index scan access methods to lookup access methods even when the latter were much cheaper. The problem was not observed in 4.1 for the reported query because the WHERE condition was not of a form that could cause the problem. Equality propagation introduced on 5.0 added an extra predicate and changed the WHERE condition. The new condition provoked the optimizer to make a bad choice. The problem was fixed by the patch for bug 17379. mysql-test/t/select.test 1.101 06/05/11 19:46:54 igor@stripped +21 -0 Added a test case for bug #18940. The problem was fixed by the patch for bug 17379. mysql-test/r/select.result 1.123 06/05/11 19:46:54 igor@stripped +19 -0 Added a test case for bug #18940. The problem was fixed by the patch for bug 17379. # This is a BitKeeper patch. What follows are the unified diffs for the # set of deltas contained in the patch. The rest of the patch, the part # that BitKeeper cares about, is below these diffs. # User: igor # Host: rurik.mysql.com # Root: /home/igor/dev/mysql-5.0-2 --- 1.122/mysql-test/r/select.result 2006-05-10 06:40:15 -07:00 +++ 1.123/mysql-test/r/select.result 2006-05-11 19:46:54 -07:00 @@ -3427,3 +3427,22 @@ 1 SIMPLE A range PRIMARY PRIMARY 12 NULL 3 Using where 1 SIMPLE B ref PRIMARY PRIMARY 8 const,test.A.e 10 drop table t1, t2; +CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX(b)); +INSERT INTO t1 VALUES (1, 3), (9,4), (7,5), (4,5), (6,2), +(3,1), (5,1), (8,9), (2,2), (0,9); +CREATE TABLE t2 (c int, d int, f int, INDEX(c,f)); +INSERT INTO t2 VALUES +(1,0,0), (1,0,1), (2,0,0), (2,0,1), (3,0,0), (4,0,1), +(5,0,0), (5,0,1), (6,0,0), (0,0,1), (7,0,0), (7,0,1), +(0,0,0), (0,0,1), (8,0,0), (8,0,1), (9,0,0), (9,0,1); +EXPLAIN +SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 range PRIMARY,b b 5 NULL 3 Using where +1 SIMPLE t2 ref c c 5 test.t1.a 2 Using where +EXPLAIN +SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6 AND a > 0; +id select_type table type possible_keys key key_len ref rows Extra +1 SIMPLE t1 range PRIMARY,b b 5 NULL 3 Using where +1 SIMPLE t2 ref c c 5 test.t1.a 2 Using where +DROP TABLE t1, t2; --- 1.100/mysql-test/t/select.test 2006-05-10 06:40:15 -07:00 +++ 1.101/mysql-test/t/select.test 2006-05-11 19:46:54 -07:00 @@ -2899,3 +2899,24 @@ explain select * from t2 A, t2 B where A.a=5 and A.b=5 and A.C<5 and B.a=5 and B.b=A.e and (B.b =1 or B.b = 3 or B.b=5); drop table t1, t2; + +# +#Bug #18940: selection of optimal execution plan caused by equality +# propagation (the bug was fixed by the patch for bug #17379) + +CREATE TABLE t1 (a int PRIMARY KEY, b int, INDEX(b)); +INSERT INTO t1 VALUES (1, 3), (9,4), (7,5), (4,5), (6,2), + (3,1), (5,1), (8,9), (2,2), (0,9); + +CREATE TABLE t2 (c int, d int, f int, INDEX(c,f)); +INSERT INTO t2 VALUES + (1,0,0), (1,0,1), (2,0,0), (2,0,1), (3,0,0), (4,0,1), + (5,0,0), (5,0,1), (6,0,0), (0,0,1), (7,0,0), (7,0,1), + (0,0,0), (0,0,1), (8,0,0), (8,0,1), (9,0,0), (9,0,1); + +EXPLAIN +SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6; +EXPLAIN +SELECT a, c, d, f FROM t1,t2 WHERE a=c AND b BETWEEN 4 AND 6 AND a > 0; + +DROP TABLE t1, t2;