Fixed regression from r35821: the status key is meant to prevent DB overload, not...

diff --git a/includes/MessageCache.php b/includes/MessageCache.php
index 4fd7dda..2721708 100644 (file)
--- a/includes/MessageCache.php
+++ b/includes/MessageCache.php
@@ -260,12 +260,23 @@ class MessageCache {
 
                        $this->lock($cacheKey);
 
-                       $cache = $this->loadFromDB( $code );
-                       $success = $this->setCache( $cache, $code );
+                       # Limit the concurrency of loadFromDB to a single process 
+                       # This prevents the site from going down when the cache expires
+                       $statusKey = wfMemcKey( 'messages', $code, 'status' );
+                       $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
                        if ( $success ) {
-                               $this->saveToCaches( $cache, true, $code );
+                               $cache = $this->loadFromDB( $code );
+                               $success = $this->setCache( $cache, $code );
+                       }
+                       if ( $success ) {
+                               $success = $this->saveToCaches( $cache, true, $code );
+                               if ( $success ) {
+                                       $this->mMemc->delete( $statusKey );
+                               } else {
+                                       $this->mMemc->set( $statusKey, 'error', 60*5 );
+                                       wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
+                               }
                        }
-
                        $this->unlock($cacheKey);
                }
 
@@ -413,10 +424,6 @@ class MessageCache {
                global $wgLocalMessageCache, $wgLocalMessageCacheSerialized;
 
                $cacheKey = wfMemcKey( 'messages', $code );
-               $statusKey = wfMemcKey( 'messages', $code, 'status' );
-
-               $success = $this->mMemc->add( $statusKey, 'loading', MSG_LOAD_TIMEOUT );
-               if ( !$success ) return true; # Other process should be updating them now
 
                $i = 0;
                if ( $memc ) {
@@ -443,11 +450,8 @@ class MessageCache {
                }
 
                if ( $i == 20 ) {
-                       $this->mMemc->set( $statusKey, 'error', 60*5 );
-                       wfDebug( "MemCached set error in MessageCache: restart memcached server!\n" );
                        $success = false;
                } else {
-                       $this->mMemc->delete( $statusKey );
                        $success = true;
                }
                wfProfileOut( __METHOD__ );