Follow-up r79518: added getCachedLastEditTime/getCachedLastEditTime methods to WikiPa...

diff --git a/includes/WikiPage.php b/includes/WikiPage.php
index f6551aa..10b4809 100644 (file)
--- a/includes/WikiPage.php
+++ b/includes/WikiPage.php
@@ -350,19 +350,28 @@ class WikiPage extends Page {
         *              A DB query result object or...
         *              "fromdb" to get from a slave DB or...
         *              "fromdbmaster" to get from the master DB
+        * @return void
         */
        public function loadPageData( $data = 'fromdb' ) {
-               if ( $data === 'fromdb' || $data === 'fromdbmaster' ) {
-                       $db = ( $data == 'fromdbmaster' )
-                               ? wfGetDB( DB_MASTER )
-                               : wfGetDB( DB_SLAVE );
-                       $data = $this->pageDataFromTitle( $db, $this->mTitle );
+               if ( $data === 'fromdbmaster' ) {
+                       $data = $this->pageDataFromTitle( wfGetDB( DB_MASTER ), $this->mTitle );
+               } elseif ( $data === 'fromdb' ) { // slave
+                       $data = $this->pageDataFromTitle( wfGetDB( DB_SLAVE ), $this->mTitle );
+                       # Use a "last rev inserted" timestamp key to dimish the issue of slave lag.
+                       # Note that DB also stores the master position in the session and checks it.
+                       $touched = $this->getCachedLastEditTime();
+                       if ( $touched ) { // key set
+                               if ( !$data || $touched > wfTimestamp( TS_MW, $data->page_touched ) ) {
+                                       $data = $this->pageDataFromTitle( wfGetDB( DB_MASTER ), $this->mTitle );
+                               }
+                       }
                }
 
                $lc = LinkCache::singleton();
 
                if ( $data ) {
-                       $lc->addGoodLinkObj( $data->page_id, $this->mTitle, $data->page_len, $data->page_is_redirect, $data->page_latest );
+                       $lc->addGoodLinkObj( $data->page_id, $this->mTitle,
+                               $data->page_len, $data->page_is_redirect, $data->page_latest );
 
                        $this->mTitle->loadFromRow( $data );
 
@@ -814,10 +823,11 @@ class WikiPage extends Page {
                        $conditions['page_latest'] = $lastRevision;
                }
 
+               $now = wfTimestampNow();
                $dbw->update( 'page',
                        array( /* SET */
                                'page_latest'      => $revision->getId(),
-                               'page_touched'     => $dbw->timestamp(),
+                               'page_touched'     => $dbw->timestamp( $now ),
                                'page_is_new'      => ( $lastRevision === 0 ) ? 1 : 0,
                                'page_is_redirect' => $rt !== null ? 1 : 0,
                                'page_len'         => strlen( $text ),
@@ -828,12 +838,34 @@ class WikiPage extends Page {
                $result = $dbw->affectedRows() != 0;
                if ( $result ) {
                        $this->updateRedirectOn( $dbw, $rt, $lastRevIsRedirect );
+                       $this->setCachedLastEditTime( $now );
                }
 
                wfProfileOut( __METHOD__ );
                return $result;
        }
 
+       /**
+        * Get the cached timestamp for the last time the page changed
+        * @return string MW timestamp
+        */
+       protected function getCachedLastEditTime() {
+               global $wgMemc;
+               $key = wfMemcKey( 'page-lastedit', md5( $this->mTitle->getPrefixedDBkey() ) );
+               return $wgMemc->get( $key );
+       }
+
+       /**
+        * Set the cached timestamp for the last time the page changed
+        * @param $timestamp string
+        * @return void
+        */
+       protected function setCachedLastEditTime( $timestamp ) {
+               global $wgMemc;
+               $key = wfMemcKey( 'page-lastedit', md5( $this->mTitle->getPrefixedDBkey() ) );
+               $wgMemc->set( $key, wfTimestamp( TS_MW, $timestamp ), 60*15 );
+       }
+
        /**
         * Add row to the redirect table if this is a redirect, remove otherwise.
         *