From: Date: September 27 2006 12:11pm
Subject: bk commit into 5.1 tree (gkodinov:1.2338) BUG#21174
List-Archive: http://lists.mysql.com/commits/12597
X-Bug: 21174
Message-Id: <20060927101126.4DCCD5AE451@macbook.gmz>

Below is the list of changes that have just been committed into a local
5.1 repository of kgeorge. When kgeorge 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@stripped, 2006-09-27 13:11:00+03:00, gkodinov@stripped +3 -0
  Bug#21174: Index degrades sort performance and optimizer does not honor IGNORE INDEX
   - fix moved to 5.1

  mysql-test/r/group_by.result@stripped, 2006-09-27 13:10:48+03:00, gkodinov@stripped +9 -0
    Bug#21174: Index degrades sort performance and optimizer does not honor IGNORE INDEX
     - fix moved to 5.1

  mysql-test/t/group_by.test@stripped, 2006-09-27 13:10:49+03:00, gkodinov@stripped +12 -0
    Bug#21174: Index degrades sort performance and optimizer does not honor IGNORE INDEX
     - fix moved to 5.1

  sql/sql_select.cc@stripped, 2006-09-27 13:10:50+03:00, gkodinov@stripped +2 -0
    Bug#21174: Index degrades sort performance and optimizer does not honor IGNORE INDEX
     - fix moved to 5.1

# 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:	gkodinov
# Host:	macbook.gmz
# Root:	/Users/kgeorge/mysql/work/B21174-5.1-opt

--- 1.442/sql/sql_select.cc	2006-09-27 13:11:25 +03:00
+++ 1.443/sql/sql_select.cc	2006-09-27 13:11:25 +03:00
@@ -11875,6 +11875,8 @@ test_if_skip_sort_order(JOIN_TAB *tab,OR
     We must not try to use disabled keys.
   */
   usable_keys= table->s->keys_in_use;
+  /* we must not consider keys that are disabled by IGNORE INDEX */
+  usable_keys.intersect(table->keys_in_use_for_query);
 
   for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
   {

--- 1.73/mysql-test/r/group_by.result	2006-09-27 13:11:25 +03:00
+++ 1.74/mysql-test/r/group_by.result	2006-09-27 13:11:25 +03:00
@@ -821,3 +821,12 @@ a	b	real_b
 68	France	France
 DROP VIEW v1;
 DROP TABLE t1,t2;
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 VALUES (1, 1), (2, 2), (3,3), (4,4);
+EXPLAIN SELECT a, SUM(b) FROM t1 GROUP BY a LIMIT 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	index	NULL	a	5	NULL	4	
+EXPLAIN SELECT a, SUM(b) FROM t1 IGNORE INDEX (a) GROUP BY a LIMIT 2;
+id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
+1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	4	Using temporary; Using filesort
+DROP TABLE t1;

--- 1.59/mysql-test/t/group_by.test	2006-09-27 13:11:25 +03:00
+++ 1.60/mysql-test/t/group_by.test	2006-09-27 13:11:25 +03:00
@@ -655,3 +655,15 @@ where t2.b=v1.a GROUP BY t2.b;
 
 DROP VIEW v1;
 DROP TABLE t1,t2;
+
+#
+# Bug #21174: Index degrades sort performance and 
+#             optimizer does not honor IGNORE INDEX
+#
+CREATE TABLE t1 (a INT, b INT, KEY(a));
+INSERT INTO t1 VALUES (1, 1), (2, 2), (3,3), (4,4);
+
+EXPLAIN SELECT a, SUM(b) FROM t1 GROUP BY a LIMIT 2; 
+EXPLAIN SELECT a, SUM(b) FROM t1 IGNORE INDEX (a) GROUP BY a LIMIT 2;
+
+DROP TABLE t1;