From c312218534e7d4065a2b474b084f6c5727275707 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Wed, 21 Aug 2013 13:20:40 -0700
Subject: [PATCH] Move slow deletion purges out of complex DB transactions

* This should help reduce deletion related deadlock errors

Change-Id: Ie7cafbf87ab0c71cc6c4c4fe1e53af364974a745
---
 includes/filerepo/file/LocalFile.php | 32 +++++++++++++++++-----------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/includes/filerepo/file/LocalFile.php b/includes/filerepo/file/LocalFile.php
index 678a6ad27a..39ef62c6e3 100644
--- a/includes/filerepo/file/LocalFile.php
+++ b/includes/filerepo/file/LocalFile.php
@@ -1527,7 +1527,6 @@ class LocalFile extends File {
 	 * @return FileRepoStatus object.
 	 */
 	function delete( $reason, $suppress = false ) {
-		global $wgUseSquid;
 		if ( $this->getRepo()->getReadOnlyReason() !== false ) {
 			return $this->readOnlyFatalStatus();
 		}
@@ -1545,19 +1544,28 @@ class LocalFile extends File {
 			DeferredUpdates::addUpdate( SiteStatsUpdate::factory( array( 'images' => -1 ) ) );
 		}
 
-		$this->purgeEverything();
-		foreach ( $archiveNames as $archiveName ) {
-			$this->purgeOldThumbnails( $archiveName );
-		}
+		// Hack: the lock()/unlock() pair is nested in a transaction so the locking is not
+		// tied to BEGIN/COMMIT. To avoid slow purges in the transaction, move them outside.
+		$file = $this;
+		$this->getRepo()->getMasterDB()->onTransactionIdle(
+			function() use ( $file, $archiveNames ) {
+				global $wgUseSquid;
 
-		if ( $wgUseSquid ) {
-			// Purge the squid
-			$purgeUrls = array();
-			foreach ($archiveNames as $archiveName ) {
-				$purgeUrls[] = $this->getArchiveUrl( $archiveName );
+				$file->purgeEverything();
+				foreach ( $archiveNames as $archiveName ) {
+					$file->purgeOldThumbnails( $archiveName );
+				}
+
+				if ( $wgUseSquid ) {
+					// Purge the squid
+					$purgeUrls = array();
+					foreach ( $archiveNames as $archiveName ) {
+						$purgeUrls[] = $file->getArchiveUrl( $archiveName );
+					}
+					SquidUpdate::purge( $purgeUrls );
+				}
 			}
-			SquidUpdate::purge( $purgeUrls );
-		}
+		);
 
 		return $status;
 	}
-- 
2.20.1