From 2d4db52edac1488c9481b303095229b424288e64 Mon Sep 17 00:00:00 2001 From: Evgeny Potemkin Date: Fri, 26 Feb 2010 14:17:00 +0300 Subject: Bug#50843: Filesort used instead of clustered index led to performance degradation. Filesort + join cache combination is preferred to full index scan because it is usually faster. But it's not the case when the index is clustered one. Now test_if_skip_sort_order function prefers filesort only if index isn't clustered. mysql-test/r/innodb_mysql.result: Added a test case for the bug#50843. mysql-test/t/innodb_mysql.test: Added a test case for the bug#50843. sql/sql_select.cc: Bug#50843: Filesort used instead of clustered index led to performance degradation. Now test_if_skip_sort_order function prefers filesort only if index isn't clustered. --- mysql-test/t/innodb_mysql.test | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'mysql-test/t/innodb_mysql.test') diff --git a/mysql-test/t/innodb_mysql.test b/mysql-test/t/innodb_mysql.test index d9fecccfbdc..a3c11b8b8d6 100644 --- a/mysql-test/t/innodb_mysql.test +++ b/mysql-test/t/innodb_mysql.test @@ -545,5 +545,17 @@ CREATE TABLE t1 (a INT PRIMARY KEY) ENGINE=innodb ; SELECT 1 FROM t1 JOIN t1 a USING(a) GROUP BY t1.a,t1.a; DROP TABLE t1; +--echo # +--echo # Bug#50843: Filesort used instead of clustered index led to +--echo # performance degradation. +--echo # +create table t1(f1 int not null primary key, f2 int) engine=innodb; +create table t2(f1 int not null, key (f1)) engine=innodb; +insert into t1 values (1,1),(2,2),(3,3); +insert into t2 values (1),(2),(3); +explain select t1.* from t1 left join t2 using(f1) group by t1.f1; +drop table t1,t2; +--echo # + --echo End of 5.1 tests -- cgit v1.2.1