From 661796389f88dc2d436441156dd9d52da2407068 Mon Sep 17 00:00:00 2001 From: unknown Date: Thu, 11 Jan 2007 16:05:03 +0300 Subject: Bug#17711: DELETE doesn't use index when ORDER BY, LIMIT and non-restricting WHERE is present. If a DELETE statement with ORDER BY and LIMIT contains a WHERE clause with conditions that for sure cannot be used for index access (like in WHERE @var:= field) the execution always follows the filesort path. It happens currently even when for the above case there is an index that can be used to speedup sorting by the order by list. Now if a DELETE statement with ORDER BY and LIMIT contains such WHERE clause conditions that cannot be used to build any quick select then the mysql_delete() tries to use an index like there is no WHERE clause at all. mysql-test/t/delete.test: Added a test case for bug#17711: DELETE doesn't use index when ORDER BY, LIMIT and non-restricting WHERE is present. mysql-test/r/delete.result: Added a test case for bug#17711: DELETE doesn't use index when ORDER BY, LIMIT and non-restricting WHERE is present. sql/sql_delete.cc: Bug#17711: DELETE doesn't use index when ORDER BY, LIMIT and non-restricting WHERE is present. Now if a DELETE statement with ORDER BY and LIMIT contains such WHERE clause conditions that cannot be used to build any quick select then the mysql_delete() tries to use an index like there is no WHERE clause at all. --- mysql-test/t/delete.test | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'mysql-test/t/delete.test') diff --git a/mysql-test/t/delete.test b/mysql-test/t/delete.test index 2036b59d810..301b2cdbb99 100644 --- a/mysql-test/t/delete.test +++ b/mysql-test/t/delete.test @@ -174,4 +174,14 @@ delete from t1 where a is null; select count(*) from t1; drop table t1; +# +# Bug#17711: DELETE doesn't use index when ORDER BY, LIMIT and +# non-restricting WHERE is present. +# +create table t1(f1 int primary key); +insert into t1 values (4),(3),(1),(2); +delete from t1 where (@a:= f1) order by f1 limit 1; +select @a; +drop table t1; + --echo End of 4.1 tests -- cgit v1.2.1