Fix for concurrent image description page update problem.

diff --git a/includes/LinksUpdate.php b/includes/LinksUpdate.php
index 742a076..bd09502 100644 (file)
--- a/includes/LinksUpdate.php
+++ b/includes/LinksUpdate.php
@@ -173,29 +173,60 @@ class LinksUpdate {
 
                wfProfileOut( $fname );
        }
+       
+       /**
+        * Invalidate the cache of a list of pages from a single namespace
+        *
+        * @param integer $namespace
+        * @param array $dbkeys
+        */
+       function invalidatePages( $namespace, $dbkeys ) {
+               $fname = 'LinksUpdate::invalidatePages';
+               
+               if ( !count( $dbkeys ) ) {
+                       return;
+               }
+               
+               /**
+                * Determine which pages need to be updated
+                * This is necessary to prevent the job queue from smashing the DB with
+                * large numbers of concurrent invalidations of the same page
+                */
+               $now = $this->mDb->timestamp();
+               $ids = array();
+               $res = $this->mDb->select( 'page', array( 'page_id' ), 
+                       array( 
+                               'page_namespace' => $namespace,
+                               'page_title IN (' . $this->mDb->makeList( $dbkeys ) . ')',
+                               'page_touched < ' . $this->mDb->addQuotes( $now )
+                       ), $fname
+               );
+               while ( $row = $this->mDb->fetchObject( $res ) ) {
+                       $ids[] = $row->page_id;
+               }
+               if ( !count( $ids ) ) {
+                       return;
+               }
+               
+               /**
+                * Do the update
+                * We still need the page_touched condition, in case the row has changed since 
+                * the non-locking select above.
+                */
+               $this->mDb->update( 'page', array( 'page_touched' => $now ), 
+                       array( 
+                               'page_id IN (' . $this->mDb->makeList( $ids ) . ')',
+                               'page_touched < ' . $this->mDb->addQuotes( $now )
+                       ), $fname
+               );
+       }
 
        function invalidateCategories( $cats ) {
-               $fname = 'LinksUpdate::invalidateCategories';
-               if ( count( $cats ) ) {
-                       $this->mDb->update( 'page', array( 'page_touched' => $this->mDb->timestamp() ),
-                               array(
-                                       'page_namespace' => NS_CATEGORY,
-                                       'page_title IN (' . $this->mDb->makeList( array_keys( $cats ) ) . ')'
-                               ), $fname
-                       );
-               }
+               $this->invalidatePages( NS_CATEGORY, array_keys( $cats ) );
        }
 
        function invalidateImageDescriptions( $images ) {
-               $fname = 'LinksUpdate::invalidateImageDescriptions';
-               if ( count( $images ) ) {
-                       $this->mDb->update( 'page', array( 'page_touched' => $this->mDb->timestamp() ),
-                               array(
-                                       'page_namespace' => NS_IMAGE,
-                                       'page_title IN (' . $this->mDb->makeList( array_keys( $images ) ) . ')'
-                               ), $fname
-                       );
-               }
+               $this->invalidatePages( NS_IMAGE, array_keys( $images ) );
        }
 
        function dumbTableUpdate( $table, $insertions, $fromField ) {