From: Aaron Schulz <aschulz@wikimedia.org>
Date: Fri, 19 Aug 2016 18:31:41 +0000 (-0700)
Subject: Avoid INSERT..SELECT in MovePage
X-Git-Tag: 1.31.0-rc.0~5966^2
X-Git-Url: http://git.cyclocoop.org///%22%40url%40//%22?a=commitdiff_plain;h=7cd8913897761f06c5aca1e9eedb6844355c934b;p=lhc%2Fweb%2Fwiklou.git

Avoid INSERT..SELECT in MovePage

That construct has poor locking characteristics in terms of
auto-inc columns as well as not allowing such inserts concurrently
for statement-based replication. Also, the INSERT..SELECT did not
have an ORDER BY, which could lead to pr_id drift with statement
based replication.

Change-Id: I47ca89abcbe4598d3b56cf077a47055500a0647f
---

diff --git a/includes/MovePage.php b/includes/MovePage.php
index bc3305ab04..d17f23422d 100644
--- a/includes/MovePage.php
+++ b/includes/MovePage.php
@@ -297,19 +297,25 @@ class MovePage {
 
 		if ( $protected ) {
 			# Protect the redirect title as the title used to be...
-			$dbw->insertSelect( 'page_restrictions', 'page_restrictions',
-				[
-					'pr_page' => $redirid,
-					'pr_type' => 'pr_type',
-					'pr_level' => 'pr_level',
-					'pr_cascade' => 'pr_cascade',
-					'pr_user' => 'pr_user',
-					'pr_expiry' => 'pr_expiry'
-				],
+			$res = $dbw->select(
+				'page_restrictions',
+				'*',
 				[ 'pr_page' => $pageid ],
 				__METHOD__,
-				[ 'IGNORE' ]
+				'FOR UPDATE'
 			);
+			$rowsInsert = [];
+			foreach ( $res as $row ) {
+				$rowsInsert[] = [
+					'pr_page' => $redirid,
+					'pr_type' => $row->pr_type,
+					'pr_level' => $row->pr_level,
+					'pr_cascade' => $row->pr_cascade,
+					'pr_user' => $row->pr_user,
+					'pr_expiry' => $row->pr_expiry
+				];
+			}
+			$dbw->insert( 'page_restrictions', $rowsInsert, __METHOD__, [ 'IGNORE' ] );
 
 			// Build comment for log
 			$comment = wfMessage(