Merge "MovePage: Fix old, old bug with moving over redirects"

[lhc/web/wiklou.git] / includes / db / loadbalancer / LBFactory.php

diff --git a/includes/db/loadbalancer/LBFactory.php b/includes/db/loadbalancer/LBFactory.php
index 053f9f8..efc6148 100644 (file)
--- a/includes/db/loadbalancer/LBFactory.php
+++ b/includes/db/loadbalancer/LBFactory.php
@@ -31,16 +31,19 @@ use MediaWiki\Logger\LoggerFactory;
  * @ingroup Database
  */
 abstract class LBFactory implements DestructibleService {
-
        /** @var ChronologyProtector */
        protected $chronProt;
-
        /** @var TransactionProfiler */
        protected $trxProfiler;
-
        /** @var LoggerInterface */
-       protected $logger;
-
+       protected $trxLogger;
+       /** @var BagOStuff */
+       protected $srvCache;
+       /** @var WANObjectCache */
+       protected $wanCache;
+
+       /** @var mixed */
+       protected $ticket;
        /** @var string|bool Reason all LBs are read-only or false if not */
        protected $readOnlyReason = false;
 
@@ -49,15 +52,29 @@ abstract class LBFactory implements DestructibleService {
        /**
         * Construct a factory based on a configuration array (typically from $wgLBFactoryConf)
         * @param array $conf
+        * @TODO: inject objects via dependency framework
         */
        public function __construct( array $conf ) {
                if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
                        $this->readOnlyReason = $conf['readOnlyReason'];
                }
-
                $this->chronProt = $this->newChronologyProtector();
                $this->trxProfiler = Profiler::instance()->getTransactionProfiler();
-               $this->logger = LoggerFactory::getInstance( 'DBTransaction' );
+               // Use APC/memcached style caching, but avoids loops with CACHE_DB (T141804)
+               $cache = ObjectCache::getLocalServerInstance();
+               if ( $cache->getQoS( $cache::ATTR_EMULATION ) > $cache::QOS_EMULATION_SQL ) {
+                       $this->srvCache = $cache;
+               } else {
+                       $this->srvCache = new EmptyBagOStuff();
+               }
+               $wCache = ObjectCache::getMainWANInstance();
+               if ( $wCache->getQoS( $wCache::ATTR_EMULATION ) > $wCache::QOS_EMULATION_SQL ) {
+                       $this->wanCache = $wCache;
+               } else {
+                       $this->wanCache = WANObjectCache::newEmpty();
+               }
+               $this->trxLogger = LoggerFactory::getInstance( 'DBTransaction' );
+               $this->ticket = mt_rand();
        }
 
        /**
@@ -261,7 +278,7 @@ abstract class LBFactory implements DestructibleService {
                        foreach ( $callersByDB as $db => $callers ) {
                                $msg .= "$db: " . implode( '; ', $callers ) . "\n";
                        }
-                       $this->logger->info( $msg );
+                       $this->trxLogger->info( $msg );
                }
        }
 
@@ -390,6 +407,44 @@ abstract class LBFactory implements DestructibleService {
                }
        }
 
+       /**
+        * Get a token asserting that no transaction writes are active
+        *
+        * @param string $fname Caller name (e.g. __METHOD__)
+        * @return mixed A value to pass to commitAndWaitForReplication()
+        * @since 1.28
+        */
+       public function getEmptyTransactionTicket( $fname ) {
+               if ( $this->hasMasterChanges() ) {
+                       $this->trxLogger->error( __METHOD__ . ": $fname does not have outer scope." );
+                       return null;
+               }
+
+               return $this->ticket;
+       }
+
+       /**
+        * Convenience method for safely running commitMasterChanges()/waitForReplication()
+        *
+        * This will commit and wait unless $ticket indicates it is unsafe to do so
+        *
+        * @param string $fname Caller name (e.g. __METHOD__)
+        * @param mixed $ticket Result of getOuterTransactionScopeTicket()
+        * @param array $opts Options to waitForReplication()
+        * @throws DBReplicationWaitError
+        * @since 1.28
+        */
+       public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
+               if ( $ticket !== $this->ticket ) {
+                       $logger = LoggerFactory::getInstance( 'DBPerformance' );
+                       $logger->error( __METHOD__ . ": cannot commit; $fname does not have outer scope." );
+                       return;
+               }
+
+               $this->commitMasterChanges( $fname );
+               $this->waitForReplication( $opts );
+       }
+
        /**
         * Disable the ChronologyProtector for all load balancers
         *