From b29e8ea02528b29f3ae66f405c01338684e8efee Mon Sep 17 00:00:00 2001
From: Roan Kattouw <catrope@users.mediawiki.org>
Date: Wed, 22 Dec 2010 15:58:15 +0000
Subject: [PATCH] Performance crusade in SpecialListredirects: * Use the rd_*
 fields to build redirect objects directly rather than running additional
 queries to grab them ** If the rd_* fields are not available (i.e. when
 running from cache), use Article::getRedirectTarget() rather than grabbing
 the revision text * Preload the existence status of the redirects and their
 targets in a LinkBatch so Linker::link() won't query them one at a time

---
 includes/specials/SpecialListredirects.php | 48 +++++++++++++++++-----
 1 file changed, 38 insertions(+), 10 deletions(-)

diff --git a/includes/specials/SpecialListredirects.php b/includes/specials/SpecialListredirects.php
index 850466272a..21f8aec342 100644
--- a/includes/specials/SpecialListredirects.php
+++ b/includes/specials/SpecialListredirects.php
@@ -45,6 +45,8 @@ class ListredirectsPage extends QueryPage {
 					'p1.page_title AS title',
 					'rd_namespace',
 					'rd_title',
+					'rd_fragment',
+					'rd_interwiki',
 					'p2.page_id AS redirid' ),
 			'conds' => array( 'p1.page_is_redirect' => 1 ),
 			'join_conds' => array( 'redirect' => array(
@@ -58,6 +60,37 @@ class ListredirectsPage extends QueryPage {
 	function getOrderFields() {
 		return array ( 'p1.page_namespace', 'p1.page_title' );
 	}
+	
+	/**
+	 * Cache page existence for performance
+	 */
+	function preprocessResults( $db, $res ) {
+		$batch = new LinkBatch;
+		foreach ( $res as $row ) {
+			$batch->add( $row->namespace, $row->title );
+			$batch->addObj( $this->getRedirectTarget( $row ) );
+		}
+		$batch->execute();
+
+		// Back to start for display
+		if ( $db->numRows( $res ) > 0 ) {
+			// If there are no rows we get an error seeking.
+			$db->dataSeek( $res, 0 );
+		}
+	}
+	
+	protected function getRedirectTarget( $row ) {
+		if ( isset( $row->rd_title ) ) {
+			return Title::makeTitle( $row->rd_namespace,
+				$row->rd_title, $row->rd_fragment,
+				$row->rd_interwiki
+			);
+		} else {
+			$title = Title::makeTitle( $row->namespace, $row->title );
+			$article = new Article( $title );
+			return $article->getRedirectTarget();
+		}
+	}
 
 	function formatResult( $skin, $result ) {
 		global $wgContLang;
@@ -72,17 +105,12 @@ class ListredirectsPage extends QueryPage {
 		);
 
 		# Find out where the redirect leads
-		$revision = Revision::newFromTitle( $rd_title );
-		if( $revision ) {
+		$target = $this->getRedirectTarget( $result );
+		if( $target ) {
 			# Make a link to the destination page
-			$target = Title::newFromRedirect( $revision->getText() );
-			if( $target ) {
-				$arr = $wgContLang->getArrow() . $wgContLang->getDirMark();
-				$targetLink = $skin->link( $target );
-				return "$rd_link $arr $targetLink";
-			} else {
-				return "<del>$rd_link</del>";
-			}
+			$arr = $wgContLang->getArrow() . $wgContLang->getDirMark();
+			$targetLink = $skin->link( $target );
+			return "$rd_link $arr $targetLink";
 		} else {
 			return "<del>$rd_link</del>";
 		}
-- 
2.20.1