From: Tim Starling <tstarling@users.mediawiki.org>
Date: Fri, 9 Sep 2011 03:51:45 +0000 (+0000)
Subject: * Added a script to reduce disk space on a MySQL parser cache setup such as the one... 
X-Git-Tag: 1.31.0-rc.0~27774
X-Git-Url: https://git.cyclocoop.org/%242?a=commitdiff_plain;h=cac02778e4f8fd660e8c212562f5164c45477a19;p=lhc%2Fweb%2Fwiklou.git

* Added a script to reduce disk space on a MySQL parser cache setup such as the one at Wikimedia at the moment, by removing all objects which expire before a given time.
* Fixed unintentional shortcut evaluation in MultiWriteBagOStuff::doWrite(). It would have caused writes to be skipped on the second cache if the first cache failed, now writes should be attempted on all caches.
---

diff --git a/includes/objectcache/BagOStuff.php b/includes/objectcache/BagOStuff.php
index 634eff35f7..97b6cb2cda 100644
--- a/includes/objectcache/BagOStuff.php
+++ b/includes/objectcache/BagOStuff.php
@@ -91,6 +91,16 @@ abstract class BagOStuff {
 		return array();
 	}
 
+	/**
+	 * Delete all objects expiring before a certain date. 
+	 *
+	 * @return true on success, false if unimplemented
+	 */
+	public function deleteObjectsExpiringBefore( $date ) {
+		// stub
+		return false;
+	}
+
 	/* *** Emulated functions *** */
 
 	public function add( $key, $value, $exptime = 0 ) {
diff --git a/includes/objectcache/MultiWriteBagOStuff.php b/includes/objectcache/MultiWriteBagOStuff.php
index 4ed1188d35..2b88b427c9 100644
--- a/includes/objectcache/MultiWriteBagOStuff.php
+++ b/includes/objectcache/MultiWriteBagOStuff.php
@@ -89,9 +89,25 @@ class MultiWriteBagOStuff extends BagOStuff {
 		array_shift( $args );
 
 		foreach ( $this->caches as $cache ) {
-			$ret = $ret && call_user_func_array( array( $cache, $method ), $args );
+			if ( !call_user_func_array( array( $cache, $method ), $args ) ) {
+				$ret = false;
+			}
 		}
 		return $ret;
 	}
 
+	/**
+	 * Delete objects expiring before a certain date. 
+	 *
+	 * Succeed if any of the child caches succeed.
+	 */
+	public function deleteObjectsExpiringBefore( $date ) {
+		$ret = false;
+		foreach ( $this->caches as $cache ) {
+			if ( $cache->deleteObjectsExpiringBefore( $date ) ) {
+				$ret = true;
+			}
+		}
+		return $ret;
+	}
 }
diff --git a/includes/objectcache/SqlBagOStuff.php b/includes/objectcache/SqlBagOStuff.php
index 7eb125ac70..78817d0bef 100644
--- a/includes/objectcache/SqlBagOStuff.php
+++ b/includes/objectcache/SqlBagOStuff.php
@@ -305,21 +305,29 @@ class SqlBagOStuff extends BagOStuff {
 	}
 
 	public function expireAll() {
+		$this->deleteObjectsExpiringBefore( wfTimestampNow() );
+	}
+
+	/**
+	 * Delete objects from the database which expire before a certain date.
+	 */
+	public function deleteObjectsExpiringBefore( $timestamp ) {
 		$db = $this->getDB();
-		$now = $db->timestamp();
+		$dbTimestamp = $db->timestamp( $timestamp );
 
 		try {
 			for ( $i = 0; $i < $this->shards; $i++ ) {
 				$db->begin();
 				$db->delete(
 					$this->getTableByShard( $i ), 
-					array( 'exptime < ' . $db->addQuotes( $now ) ), 
+					array( 'exptime < ' . $db->addQuotes( $dbTimestamp ) ), 
 					__METHOD__ );
 				$db->commit();
 			}
 		} catch ( DBQueryError $e ) {
 			$this->handleWriteError( $e );
 		}
+		return true;
 	}
 
 	public function deleteAll() {
diff --git a/maintenance/purgeParserCache.php b/maintenance/purgeParserCache.php
new file mode 100644
index 0000000000..4b550b6e4c
--- /dev/null
+++ b/maintenance/purgeParserCache.php
@@ -0,0 +1,43 @@
+<?php
+
+require( dirname( __FILE__ ) . '/Maintenance.php' );
+
+class PurgeParserCache extends Maintenance {
+	function __construct() {
+		parent::__construct();
+		$this->addDescription( "Remove old objects from the parser cache. " . 
+			"This only works when the parser cache is in an SQL database." );
+		$this->addOption( 'expiredate', 'Delete objects expiring before this date.', false, true );
+		$this->addOption( 'age', 
+			'Delete objects created more than this many seconds ago, assuming $wgParserCacheExpireTime '.
+				'has been consistent.',	
+			false, true );
+	}
+
+	function execute() {
+		$inputDate = $this->getOption( 'expiredate' );
+		$inputAge = $this->getOption( 'age' );
+		if ( $inputDate !== null ) {
+			$date = wfTimestamp( TS_MW, strtotime( $inputDate ) );
+		} elseif ( $inputAge !== null ) {
+			global $wgParserCacheExpireTime;
+			$date = wfTimestamp( TS_MW, time() + $wgParserCacheExpireTime - intval( $inputAge ) );
+		} else {
+			echo "Must specify either --expiredate or --age\n";
+			exit( 1 );
+		}
+
+		$english = Language::factory( 'en' );
+		echo "Deleting objects expiring before " . $english->timeanddate( $date ) . "\n";
+
+		$pc = wfGetParserCacheStorage();
+		$success = $pc->deleteObjectsExpiringBefore( $date );
+		if ( !$success ) {
+			echo "Cannot purge this kind of parser cache.\n";
+			exit( 1 );
+		}
+		echo "Done\n";
+	}
+}
+$maintClass = 'PurgeParserCache';
+require_once( RUN_MAINTENANCE_IF_MAIN );