From d8a12160a21b404697f138f345d3fe2dbdd289b5 Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Mon, 16 Feb 2015 14:33:44 -0800
Subject: [PATCH] Removed overzealous caching from JobQueueFederated

Change-Id: Id3a80dc89e5b46d6d95180e73e753b38a476eb36
---
 includes/jobqueue/JobQueueFederated.php | 55 ++-----------------------
 1 file changed, 3 insertions(+), 52 deletions(-)

diff --git a/includes/jobqueue/JobQueueFederated.php b/includes/jobqueue/JobQueueFederated.php
index 4186204d60..40936b76a6 100644
--- a/includes/jobqueue/JobQueueFederated.php
+++ b/includes/jobqueue/JobQueueFederated.php
@@ -54,15 +54,9 @@ class JobQueueFederated extends JobQueue {
 	/** @var array (partition name => JobQueue) reverse sorted by weight */
 	protected $partitionQueues = array();
 
-	/** @var BagOStuff */
-	protected $cache;
-
 	/** @var int Maximum number of partitions to try */
 	protected $maxPartitionsTry;
 
-	const CACHE_TTL_SHORT = 30; // integer; seconds to cache info without re-validating
-	const CACHE_TTL_LONG = 300; // integer; seconds to cache info that is kept up to date
-
 	/**
 	 * @param array $params Possible keys:
 	 *  - sectionsByWiki      : A map of wiki IDs to section names.
@@ -126,8 +120,6 @@ class JobQueueFederated extends JobQueue {
 		} else {
 			$this->partitionPushRing = new HashRing( $partitionPushMap );
 		}
-		// Aggregate cache some per-queue values if there are multiple partition queues
-		$this->cache = count( $partitionMap ) > 1 ? wfGetMainCache() : new EmptyBagOStuff();
 	}
 
 	protected function supportedOrders() {
@@ -144,15 +136,6 @@ class JobQueueFederated extends JobQueue {
 	}
 
 	protected function doIsEmpty() {
-		$key = $this->getCacheKey( 'empty' );
-
-		$isEmpty = $this->cache->get( $key );
-		if ( $isEmpty === 'true' ) {
-			return true;
-		} elseif ( $isEmpty === 'false' ) {
-			return false;
-		}
-
 		$empty = true;
 		$failed = 0;
 		foreach ( $this->partitionQueues as $queue ) {
@@ -165,7 +148,6 @@ class JobQueueFederated extends JobQueue {
 		}
 		$this->throwErrorIfAllPartitionsDown( $failed );
 
-		$this->cache->add( $key, $empty ? 'true' : 'false', self::CACHE_TTL_LONG );
 		return $empty;
 	}
 
@@ -191,13 +173,7 @@ class JobQueueFederated extends JobQueue {
 	 * @return int
 	 */
 	protected function getCrossPartitionSum( $type, $method ) {
-		$key = $this->getCacheKey( $type );
-
-		$count = $this->cache->get( $key );
-		if ( $count !== false ) {
-			return $count;
-		}
-
+		$count = 0;
 		$failed = 0;
 		foreach ( $this->partitionQueues as $queue ) {
 			try {
@@ -209,8 +185,6 @@ class JobQueueFederated extends JobQueue {
 		}
 		$this->throwErrorIfAllPartitionsDown( $failed );
 
-		$this->cache->set( $key, $count, self::CACHE_TTL_SHORT );
-
 		return $count;
 	}
 
@@ -279,10 +253,7 @@ class JobQueueFederated extends JobQueue {
 				$ok = false;
 				MWExceptionHandler::logException( $e );
 			}
-			if ( $ok ) {
-				$key = $this->getCacheKey( 'empty' );
-				$this->cache->set( $key, 'false', self::CACHE_TTL_LONG );
-			} else {
+			if ( !$ok ) {
 				if ( !$partitionRing->ejectFromLiveRing( $partition, 5 ) ) { // blacklist
 					throw new JobQueueError( "Could not insert job(s), no partitions available." );
 				}
@@ -301,10 +272,7 @@ class JobQueueFederated extends JobQueue {
 				$ok = false;
 				MWExceptionHandler::logException( $e );
 			}
-			if ( $ok ) {
-				$key = $this->getCacheKey( 'empty' );
-				$this->cache->set( $key, 'false', self::CACHE_TTL_LONG );
-			} else {
+			if ( !$ok ) {
 				if ( !$partitionRing->ejectFromLiveRing( $partition, 5 ) ) { // blacklist
 					throw new JobQueueError( "Could not insert job(s), no partitions available." );
 				}
@@ -344,9 +312,6 @@ class JobQueueFederated extends JobQueue {
 		}
 		$this->throwErrorIfAllPartitionsDown( $failed );
 
-		$key = $this->getCacheKey( 'empty' );
-		$this->cache->set( $key, 'true', self::CACHE_TTL_LONG );
-
 		return false;
 	}
 
@@ -440,10 +405,6 @@ class JobQueueFederated extends JobQueue {
 			'abandonedcount'
 		);
 
-		foreach ( $types as $type ) {
-			$this->cache->delete( $this->getCacheKey( $type ) );
-		}
-
 		/** @var JobQueue $queue */
 		foreach ( $this->partitionQueues as $queue ) {
 			$queue->doFlushCaches();
@@ -546,14 +507,4 @@ class JobQueueFederated extends JobQueue {
 			$queue->setTestingPrefix( $key );
 		}
 	}
-
-	/**
-	 * @param string $property
-	 * @return string
-	 */
-	private function getCacheKey( $property ) {
-		list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
-
-		return wfForeignMemcKey( $db, $prefix, 'jobqueue', $this->type, $property );
-	}
 }
-- 
2.20.1