Remove "memCache" field from LoadBalancer

The only user was LoadMonitor, which is converted to only use
the WAN and server caches. Previously, the lock() calls there
were useless since LBFactory never injected "memcCache" to
LoadBalancer, ergo making it EmptyBagOStuff in LoadMonitor.

Change-Id: I0c7793d47b93b763dee478d16fb87ec637dc6cab

diff --git a/includes/libs/rdbms/loadbalancer/ILoadBalancer.php b/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
index fc50961..c940392 100644 (file)
--- a/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/ILoadBalancer.php
@@ -94,7 +94,6 @@ interface ILoadBalancer {
         *  - readOnlyReason : Reason the master DB is read-only if so [optional]
         *  - waitTimeout : Maximum time to wait for replicas for consistency [optional]
         *  - srvCache : BagOStuff object for server cache [optional]
-        *  - memCache : BagOStuff object for cluster memory cache [optional]
         *  - wanCache : WANObjectCache object [optional]
         *  - chronologyProtector: ChronologyProtector object [optional]
         *  - hostname : The name of the current server [optional]

diff --git a/includes/libs/rdbms/loadbalancer/LoadBalancer.php b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
index 72217da..1df2409 100644 (file)
--- a/includes/libs/rdbms/loadbalancer/LoadBalancer.php
+++ b/includes/libs/rdbms/loadbalancer/LoadBalancer.php
@@ -62,8 +62,6 @@ class LoadBalancer implements ILoadBalancer {
        private $chronProt;
        /** @var BagOStuff */
        private $srvCache;
-       /** @var BagOStuff */
-       private $memCache;
        /** @var WANObjectCache */
        private $wanCache;
        /** @var object|string Class name or object With profileIn/profileOut methods */
@@ -187,11 +185,6 @@ class LoadBalancer implements ILoadBalancer {
                } else {
                        $this->srvCache = new EmptyBagOStuff();
                }
-               if ( isset( $params['memCache'] ) ) {
-                       $this->memCache = $params['memCache'];
-               } else {
-                       $this->memCache = new EmptyBagOStuff();
-               }
                if ( isset( $params['wanCache'] ) ) {
                        $this->wanCache = $params['wanCache'];
                } else {
@@ -244,7 +237,7 @@ class LoadBalancer implements ILoadBalancer {
                        }
 
                        $this->loadMonitor = new $class(
-                               $this, $this->srvCache, $this->memCache, $this->loadMonitorConfig );
+                               $this, $this->srvCache, $this->wanCache, $this->loadMonitorConfig );
                        $this->loadMonitor->setLogger( $this->replLogger );
                }
 

diff --git a/includes/libs/rdbms/loadmonitor/ILoadMonitor.php b/includes/libs/rdbms/loadmonitor/ILoadMonitor.php
index 4f6701f..fba5e13 100644 (file)
--- a/includes/libs/rdbms/loadmonitor/ILoadMonitor.php
+++ b/includes/libs/rdbms/loadmonitor/ILoadMonitor.php
@@ -25,6 +25,7 @@ namespace Wikimedia\Rdbms;
 
 use Psr\Log\LoggerAwareInterface;
 use BagOStuff;
+use WANObjectCache;
 
 /**
  * An interface for database load monitoring
@@ -37,11 +38,11 @@ interface ILoadMonitor extends LoggerAwareInterface {
         *
         * @param ILoadBalancer $lb LoadBalancer this instance serves
         * @param BagOStuff $sCache Local server memory cache
-        * @param BagOStuff $cCache Local cluster memory cache
+        * @param WANObjectCache $wCache Local cluster memory cache
         * @param array $options Options map
         */
        public function __construct(
-               ILoadBalancer $lb, BagOStuff $sCache, BagOStuff $cCache, array $options = []
+               ILoadBalancer $lb, BagOStuff $sCache, WANObjectCache $wCache, array $options = []
        );
 
        /**

diff --git a/includes/libs/rdbms/loadmonitor/LoadMonitor.php b/includes/libs/rdbms/loadmonitor/LoadMonitor.php
index 4300e9f..d4e73c9 100644 (file)
--- a/includes/libs/rdbms/loadmonitor/LoadMonitor.php
+++ b/includes/libs/rdbms/loadmonitor/LoadMonitor.php
@@ -25,6 +25,7 @@ use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
 use Wikimedia\ScopedCallback;
 use BagOStuff;
+use WANObjectCache;
 
 /**
  * Basic DB load monitor with no external dependencies
@@ -37,8 +38,8 @@ class LoadMonitor implements ILoadMonitor {
        protected $parent;
        /** @var BagOStuff */
        protected $srvCache;
-       /** @var BagOStuff */
-       protected $mainCache;
+       /** @var WANObjectCache */
+       protected $wanCache;
        /** @var LoggerInterface */
        protected $replLogger;
 
@@ -48,11 +49,11 @@ class LoadMonitor implements ILoadMonitor {
        const VERSION = 1; // cache key version
 
        public function __construct(
-               ILoadBalancer $lb, BagOStuff $srvCache, BagOStuff $cache, array $options = []
+               ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options = []
        ) {
                $this->parent = $lb;
                $this->srvCache = $srvCache;
-               $this->mainCache = $cache;
+               $this->wanCache = $wCache;
                $this->replLogger = new NullLogger();
 
                $this->movingAveRatio = isset( $options['movingAveRatio'] )
@@ -109,7 +110,7 @@ class LoadMonitor implements ILoadMonitor {
                $staleValue = $value ?: false;
 
                # (b) Check the shared cache and backfill APC
-               $value = $this->mainCache->get( $key );
+               $value = $this->wanCache->get( $key );
                if ( $value && $value['timestamp'] > ( microtime( true ) - $ttl ) ) {
                        $this->srvCache->set( $key, $value, $staleTTL );
                        $this->replLogger->debug( __METHOD__ . ": got lag times ($key) from main cache" );
@@ -119,12 +120,12 @@ class LoadMonitor implements ILoadMonitor {
                $staleValue = $value ?: $staleValue;
 
                # (c) Cache key missing or expired; regenerate and backfill
-               if ( $this->mainCache->lock( $key, 0, 10 ) ) {
-                       # Let this process alone update the cache value
-                       $cache = $this->mainCache;
+               if ( $this->srvCache->lock( $key, 0, 10 ) ) {
+                       # Let only this process update the cache value on this server
+                       $sCache = $this->srvCache;
                        /** @noinspection PhpUnusedLocalVariableInspection */
-                       $unlocker = new ScopedCallback( function () use ( $cache, $key ) {
-                               $cache->unlock( $key );
+                       $unlocker = new ScopedCallback( function () use ( $sCache, $key ) {
+                               $sCache->unlock( $key );
                        } );
                } elseif ( $staleValue ) {
                        # Could not acquire lock but an old cache exists, so use it
@@ -196,7 +197,7 @@ class LoadMonitor implements ILoadMonitor {
                        'weightScales' => $weightScales,
                        'timestamp' => microtime( true )
                ];
-               $this->mainCache->set( $key, $value, $staleTTL );
+               $this->wanCache->set( $key, $value, $staleTTL );
                $this->srvCache->set( $key, $value, $staleTTL );
                $this->replLogger->info( __METHOD__ . ": re-calculated lag times ($key)" );
 

diff --git a/includes/libs/rdbms/loadmonitor/LoadMonitorMySQL.php b/includes/libs/rdbms/loadmonitor/LoadMonitorMySQL.php
index ff72dbc..f8ad329 100644 (file)
--- a/includes/libs/rdbms/loadmonitor/LoadMonitorMySQL.php
+++ b/includes/libs/rdbms/loadmonitor/LoadMonitorMySQL.php
@@ -22,6 +22,7 @@
 namespace Wikimedia\Rdbms;
 
 use BagOStuff;
+use WANObjectCache;
 
 /**
  * Basic MySQL load monitor with no external dependencies
@@ -34,9 +35,9 @@ class LoadMonitorMySQL extends LoadMonitor {
        private $warmCacheRatio;
 
        public function __construct(
-               ILoadBalancer $lb, BagOStuff $srvCache, BagOStuff $cache, array $options = []
+               ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options = []
        ) {
-               parent::__construct( $lb, $srvCache, $cache, $options );
+               parent::__construct( $lb, $srvCache, $wCache, $options );
 
                $this->warmCacheRatio = isset( $options['warmCacheRatio'] )
                        ? $options['warmCacheRatio']

diff --git a/includes/libs/rdbms/loadmonitor/LoadMonitorNull.php b/includes/libs/rdbms/loadmonitor/LoadMonitorNull.php
index 8bbf9e5..6dae8cc 100644 (file)
--- a/includes/libs/rdbms/loadmonitor/LoadMonitorNull.php
+++ b/includes/libs/rdbms/loadmonitor/LoadMonitorNull.php
@@ -23,10 +23,11 @@ namespace Wikimedia\Rdbms;
 
 use Psr\Log\LoggerInterface;
 use BagOStuff;
+use WANObjectCache;
 
 class LoadMonitorNull implements ILoadMonitor {
        public function __construct(
-               ILoadBalancer $lb, BagOStuff $sCache, BagOStuff $cCache, array $options = []
+               ILoadBalancer $lb, BagOStuff $sCache, WANObjectCache $wCache, array $options = []
        ) {
        }