From: Tim Starling <tstarling@users.mediawiki.org>
Date: Mon, 15 Jun 2009 14:44:28 +0000 (+0000)
Subject: Fix incorrect index usage. Without a condition on the namespace, the use of new_name_... 
X-Git-Tag: 1.31.0-rc.0~41361
X-Git-Url: http://git.cyclocoop.org/%7B%24www_url%7Dadmin/password.php?a=commitdiff_plain;h=aaa6461083de556710a13e2b86fa423a2c10565a;p=lhc%2Fweb%2Fwiklou.git

Fix incorrect index usage. Without a condition on the namespace, the use of new_name_timestamp causes a full table scan. This was the primary cause of the recent post-scap downtime.
---

diff --git a/includes/specials/SpecialRecentchanges.php b/includes/specials/SpecialRecentchanges.php
index 79aba690bf..ab3830b70c 100644
--- a/includes/specials/SpecialRecentchanges.php
+++ b/includes/specials/SpecialRecentchanges.php
@@ -318,14 +318,14 @@ class SpecialRecentChanges extends SpecialPage {
 				array( 'rc_new' => 1 ) + $conds,
 				__METHOD__,
 				array( 'ORDER BY' => 'rc_timestamp DESC', 'LIMIT' => $limit,
-					'USE INDEX' =>  array('recentchanges' => 'new_name_timestamp') ),
+					'USE INDEX' =>  array('recentchanges' => 'rc_timestamp') ),
 				$join_conds );
 			// Old pages
 			$sqlOld = $dbr->selectSQLText( $tables, '*',
 				array( 'rc_new' => 0 ) + $conds,
 				__METHOD__,
 				array( 'ORDER BY' => 'rc_timestamp DESC', 'LIMIT' => $limit,
-					'USE INDEX' =>  array('recentchanges' => 'new_name_timestamp') ),
+					'USE INDEX' =>  array('recentchanges' => 'rc_timestamp') ),
 				$join_conds );
 			# Join the two fast queries, and sort the result set
 			$sql = $dbr->unionQueries(array($sqlNew, $sqlOld), false).' ORDER BY rc_timestamp DESC';