Make MessageCache use the immutable text cache during cache rebuilds

Only 1 message typically changed per run, so for wikis using
external storage and with many customized messages, this can
make rebuilds considerably faster.

Bug: T158084
Change-Id: Ib668e69a207e3fbeb7871f2f6a102ff1af567368

diff --git a/includes/Revision.php b/includes/Revision.php
index 4b9435a..dca2e1b 100644 (file)
--- a/includes/Revision.php
+++ b/includes/Revision.php
@@ -1240,8 +1240,9 @@ class Revision implements IDBAccessObject {
 
        /**
         * Get revision text associated with an old or archive row
-        * $row is usually an object from wfFetchRow(), both the flags and the text
-        * field must be included.
+        *
+        * Both the flags and the text field must be included. Including the old_id
+        * field will activate cache usage as long as the $wiki parameter is not set.
         *
         * @param stdClass $row The text data
         * @param string $prefix Table prefix (default 'old_')
@@ -1252,8 +1253,6 @@ class Revision implements IDBAccessObject {
         * @return string|false Text the text requested or false on failure
         */
        public static function getRevisionText( $row, $prefix = 'old_', $wiki = false ) {
-
-               # Get data
                $textField = $prefix . 'text';
                $flagsField = $prefix . 'flags';
 
@@ -1269,20 +1268,36 @@ class Revision implements IDBAccessObject {
                        return false;
                }
 
-               # Use external methods for external objects, text in table is URL-only then
+               // Use external methods for external objects, text in table is URL-only then
                if ( in_array( 'external', $flags ) ) {
                        $url = $text;
                        $parts = explode( '://', $url, 2 );
                        if ( count( $parts ) == 1 || $parts[1] == '' ) {
                                return false;
                        }
-                       $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
+
+                       if ( isset( $row->old_id ) && $wiki === false ) {
+                               // Make use of the wiki-local revision text cache
+                               $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
+                               $text = $cache->getWithSetCallback(
+                                       $cache->makeKey( 'revisiontext', 'textid', $row->old_id ),
+                                       self::getCacheTTL( $cache ),
+                                       function () use ( $url, $wiki ) {
+                                               // No negative caching per Revision::loadText()
+                                               return ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
+                                       },
+                                       [ 'pcGroup' => self::TEXT_CACHE_GROUP, 'pcTTL' => $cache::TTL_PROC_LONG ]
+                               );
+                       } else {
+                               $text = ExternalStore::fetchFromURL( $url, [ 'wiki' => $wiki ] );
+                       }
                }
 
                // If the text was fetched without an error, convert it
                if ( $text !== false ) {
                        $text = self::decompressRevisionText( $text, $flags );
                }
+
                return $text;
        }
 
@@ -1559,15 +1574,14 @@ class Revision implements IDBAccessObject {
        }
 
        /**
-        * Lazy-load the revision's text.
-        * Currently hardcoded to the 'text' table storage engine.
+        * Get the text cache TTL
         *
-        * @return string|bool The revision's text, or false on failure
+        * @param WANObjectCache $cache
+        * @return integer
         */
-       private function loadText() {
+       private static function getCacheTTL( WANObjectCache $cache ) {
                global $wgRevisionCacheExpiry;
 
-               $cache = ObjectCache::getMainWANInstance();
                if ( $cache->getQoS( $cache::ATTR_EMULATION ) <= $cache::QOS_EMULATION_SQL ) {
                        // Do not cache RDBMs blobs in...the RDBMs store
                        $ttl = $cache::TTL_UNCACHEABLE;
@@ -1575,10 +1589,22 @@ class Revision implements IDBAccessObject {
                        $ttl = $wgRevisionCacheExpiry ?: $cache::TTL_UNCACHEABLE;
                }
 
+               return $ttl;
+       }
+
+       /**
+        * Lazy-load the revision's text.
+        * Currently hardcoded to the 'text' table storage engine.
+        *
+        * @return string|bool The revision's text, or false on failure
+        */
+       private function loadText() {
+               $cache = ObjectCache::getMainWANInstance();
+
                // No negative caching; negative hits on text rows may be due to corrupted replica DBs
                return $cache->getWithSetCallback(
                        $cache->makeKey( 'revisiontext', 'textid', $this->getTextId() ),
-                       $ttl,
+                       self::getCacheTTL( $cache ),
                        function () {
                                return $this->fetchText();
                        },

diff --git a/includes/cache/MessageCache.php b/includes/cache/MessageCache.php
index 4facc20..7cd489a 100644 (file)
--- a/includes/cache/MessageCache.php
+++ b/includes/cache/MessageCache.php
@@ -508,7 +508,7 @@ class MessageCache {
 
                $res = $dbr->select(
                        [ 'page', 'revision', 'text' ],
-                       [ 'page_title', 'old_text', 'old_flags' ],
+                       [ 'page_title', 'old_id', 'old_text', 'old_flags' ],
                        $smallConds,
                        __METHOD__ . "($code)-small"
                );