From 7e63648db43724f9ca216d4c5d07c13e060a4b6b Mon Sep 17 00:00:00 2001
From: Tim Starling <tstarling@users.mediawiki.org>
Date: Mon, 25 Jul 2005 06:57:12 +0000
Subject: [PATCH] Formalising live performance hack

---
 includes/Block.php           | 16 +++++++++++++---
 includes/DefaultSettings.php |  7 +++++++
 includes/Defines.php         |  1 +
 3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/includes/Block.php b/includes/Block.php
index f97cabce15..0763133249 100644
--- a/includes/Block.php
+++ b/includes/Block.php
@@ -63,7 +63,7 @@ class Block
 	 */
 	function load( $address = '', $user = 0, $killExpired = true ) 
 	{
-		global $wgDBmysql4 ;
+		global $wgDBmysql4, $wgAntiLockFlags;
 		$fname = 'Block::load';
 		wfDebug( "Block::load: '$address', '$user', $killExpired\n" );
 
@@ -71,7 +71,11 @@ class Block
 		$killed = false;
 		if ( $this->forUpdate() ) {
 			$db =& wfGetDB( DB_MASTER );
-			$options = 'FOR UPDATE';
+			if ( $wgAntiLockFlags & ALF_NO_BLOCK_LOCK ) {
+				$options = '';
+			} else {
+				$options = 'FOR UPDATE';
+			}
 		} else {
 			$db =& wfGetDB( DB_SLAVE );
 			$options = '';
@@ -169,10 +173,16 @@ class Block
 	 */
 	/*static*/ function enumBlocks( $callback, $tag, $flags = 0 ) 
 	{
+		global $wgAntiLockFlags;
+
 		$block = new Block();
 		if ( $flags & EB_FOR_UPDATE ) {
 			$db =& wfGetDB( DB_MASTER );
-			$options = 'FOR UPDATE';
+			if ( $wgAntiLockFlags & ALF_NO_BLOCK_LOCK ) {
+				$options = '';
+			} else {
+				$options = 'FOR UPDATE';
+			}
 			$block->forUpdate( true );
 		} else {
 			$db =& wfGetDB( DB_SLAVE );
diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index cacbf1d487..f2f4836a37 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -959,6 +959,13 @@ $wgUseDumbLinkUpdate = false;
  *       Preload links during link update for save
  *   ALF_PRELOAD_EXISTENCE
  *       Preload cur_id during replaceLinkHolders
+ *   ALF_NO_LINK_LOCK
+ *       Don't use locking reads when updating the link table. This is 
+ *       necessary for wikis with a high edit rate for performance 
+ *       reasons, but may cause link table inconsistency
+ *   ALF_NO_BLOCK_LOCK
+ *       As for ALF_LINK_LOCK, this flag is a necessity for high-traffic
+ *       wikis.
  */
 $wgAntiLockFlags = 0;
 
diff --git a/includes/Defines.php b/includes/Defines.php
index 34231bf153..67789ec966 100644
--- a/includes/Defines.php
+++ b/includes/Defines.php
@@ -126,6 +126,7 @@ define( 'AV_SCAN_FAILED', false );  #scan failed (scanner not found or error in
 define( 'ALF_PRELOAD_LINKS', 1 );
 define( 'ALF_PRELOAD_EXISTENCE', 2 );
 define( 'ALF_NO_LINK_LOCK', 4 );
+define( 'ALF_NO_BLOCK_LOCK', 8 );
 /**#@-*/
 
 ?>
-- 
2.20.1