From 474a6bb80417baab499cf4f0531f423a04e3b63e Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aaron@users.mediawiki.org>
Date: Fri, 19 Dec 2008 14:51:42 +0000
Subject: [PATCH] Store negative results in cache

---
 includes/Interwiki.php | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/includes/Interwiki.php b/includes/Interwiki.php
index a98e46804f..abcef1f950 100644
--- a/includes/Interwiki.php
+++ b/includes/Interwiki.php
@@ -143,24 +143,27 @@ class Interwiki {
 		$key = wfMemcKey( 'interwiki', $prefix );
 		$mc = $wgMemc->get( $key );
 		$iw = false;
-		if( $mc && is_array( $mc ) ){ // is_array is hack for old keys
+		if( $mc && is_array( $mc ) ) { // is_array is hack for old keys
 			$iw = Interwiki::loadFromArray( $mc );
 			if( $iw ){
 				return $iw;
 			}
+		} else if( $mc === 0 ) {
+			return false; // negative result cached
 		}
-		
 		$db = wfGetDB( DB_SLAVE );
-			
 		$row = $db->fetchRow( $db->select( 'interwiki', '*', array( 'iw_prefix' => $prefix ),
 			__METHOD__ ) );
 		$iw = Interwiki::loadFromArray( $row );
-		if ( $iw ) {
+		if( $iw ) {
 			$mc = array( 'iw_url' => $iw->mURL, 'iw_local' => $iw->mLocal, 'iw_trans' => $iw->mTrans );
 			$wgMemc->add( $key, $mc );
 			return $iw;
+		} else {
+			# Pages like "Command & Conquer 3: Kane's Wrath" may keep checking
+			# the prefix. Cache the negative result to avoid extra db hits.
+			$wgMemc->add( $key, 0 );
 		}
-		
 		return false;
 	}
 
-- 
2.20.1