Merge "MessageCache: replace should actually replace, not reload"

[lhc/web/wiklou.git] / includes / cache / MessageCache.php

diff --git a/includes/cache/MessageCache.php b/includes/cache/MessageCache.php
index 733b1b7..4e0d0a7 100644 (file)
--- a/includes/cache/MessageCache.php
+++ b/includes/cache/MessageCache.php
@@ -619,11 +619,17 @@ class MessageCache {
                        return;
                }
 
-               // Reload messages from the database and pre-populate dc-local caches
-               // as optimisation. Use the master DB to avoid race conditions.
-               $cache = $this->loadFromDB( $code, self::FOR_UPDATE );
+               // Load the existing cache to update it in the local DC cache.
+               // The other DCs will see a hash mismatch.
+               if ( $this->load( $code, self::FOR_UPDATE ) ) {
+                       $cache = $this->cache->get( $code );
+               } else {
+                       // Err? Fall back to loading from the database.
+                       $cache = $this->loadFromDB( $code, self::FOR_UPDATE );
+               }
                // Check if individual cache keys should exist and update cache accordingly
                $newTextByTitle = []; // map of (title => content)
+               $newBigTitles = []; // map of (title => latest revision ID), like EXCESSIVE in loadFromDB()
                foreach ( $replacements as list( $title ) ) {
                        $page = WikiPage::factory( Title::makeTitle( NS_MEDIAWIKI, $title ) );
                        $page->loadPageData( $page::READ_LATEST );
@@ -631,15 +637,29 @@ class MessageCache {
                        // Remember the text for the blob store update later on
                        $newTextByTitle[$title] = $text;
                        // Note that if $text is false, then $cache should have a !NONEXISTANT entry
-                       if ( is_string( $text ) && strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
-                               // Match logic of loadCachedMessagePageEntry()
-                               $this->wanCache->set(
-                                       $this->bigMessageCacheKey( $cache['HASH'], $title ),
-                                       ' ' . $text,
-                                       $this->mExpiry
-                               );
+                       if ( !is_string( $text ) ) {
+                               $cache[$title] = '!NONEXISTENT';
+                       } elseif ( strlen( $text ) > $wgMaxMsgCacheEntrySize ) {
+                               $cache[$title] = '!TOO BIG';
+                               $newBigTitles[$title] = $page->getLatest();
+                       } else {
+                               $cache[$title] = ' ' . $text;
                        }
                }
+               // Update HASH for the new key. Incorporates various administrative keys,
+               // including the old HASH (and thereby the EXCESSIVE value from loadFromDB()
+               // and previous replace() calls), but that doesn't really matter since we
+               // only ever compare it for equality with a copy saved by saveToCaches().
+               $cache['HASH'] = md5( serialize( $cache + [ 'EXCESSIVE' => $newBigTitles ] ) );
+               // Update the too-big WAN cache entries now that we have the new HASH
+               foreach ( $newBigTitles as $title => $id ) {
+                       // Match logic of loadCachedMessagePageEntry()
+                       $this->wanCache->set(
+                               $this->bigMessageCacheKey( $cache['HASH'], $title ),
+                               ' ' . $newTextByTitle[$title],
+                               $this->mExpiry
+                       );
+               }
                // Mark this cache as definitely being "latest" (non-volatile) so
                // load() calls do not try to refresh the cache with replica DB data
                $cache['LATEST'] = time();