[JobQueue] Clarified documentation a bit.

[lhc/web/wiklou.git] / includes / job / JobQueueDB.php

diff --git a/includes/job/JobQueueDB.php b/includes/job/JobQueueDB.php
index 02f0784..14c1dca 100644 (file)
--- a/includes/job/JobQueueDB.php
+++ b/includes/job/JobQueueDB.php
@@ -49,15 +49,19 @@ class JobQueueDB extends JobQueue {
                        return false;
                }
 
-               $found = $this->getSlaveDB()->selectField(
-                       'job', '1', array( 'job_cmd' => $this->type ), __METHOD__
+               $found = $this->getSlaveDB()->selectField( // unclaimed job
+                       'job', '1', array( 'job_cmd' => $this->type, 'job_token' => '' ), __METHOD__
                );
-
                $wgMemc->add( $key, $found ? 'false' : 'true', self::CACHE_TTL );
+
+               return !$found;
        }
 
        /**
         * @see JobQueue::doBatchPush()
+        * @param array $jobs
+        * @param $flags
+        * @throws DBError|Exception
         * @return bool
         */
        protected function doBatchPush( array $jobs, $flags ) {
@@ -175,6 +179,7 @@ class JobQueueDB extends JobQueue {
                        }
                        $job = Job::factory( $row->job_cmd, $title,
                                self::extractBlob( $row->job_params ), $row->job_id );
+                       $job->id = $row->job_id; // XXX: work around broken subclasses
                        // Flag this job as an old duplicate based on its "root" job...
                        if ( $this->isRootJobOldDuplicate( $job ) ) {
                                $job = DuplicateJob::newFromJob( $job ); // convert to a no-op
@@ -195,7 +200,6 @@ class JobQueueDB extends JobQueue {
         */
        protected function claimRandom( $uuid, $rand, $gte ) {
                $dbw  = $this->getMasterDB();
-               $dir  = $gte ? 'ASC' : 'DESC';
                $ineq = $gte ? '>=' : '<=';
 
                $row = false; // the row acquired
@@ -209,8 +213,8 @@ class JobQueueDB extends JobQueue {
                                        'job_cmd'   => $this->type,
                                        'job_token' => '',
                                        "job_random {$ineq} {$dbw->addQuotes( $rand )}" ),
-                               __METHOD__,
-                               array( 'ORDER BY' => "job_random {$dir}" )
+                               __METHOD__
+                               // Bug 42614: "ORDER BY job_random" causes slowness on mysql for some reason
                        );
                        if ( $row ) { // claim the job
                                $dbw->update( 'job', // update by PK
@@ -366,20 +370,29 @@ class JobQueueDB extends JobQueue {
 
        /**
         * @see JobQueue::doAck()
+        * @param Job $job
+        * @throws MWException
         * @return Job|bool
         */
        protected function doAck( Job $job ) {
+               if ( !$job->getId() ) {
+                       throw new MWException( "Job of type '{$job->getType()}' has no ID." );
+               }
+
                $dbw = $this->getMasterDB();
                $dbw->commit( __METHOD__, 'flush' ); // flush existing transaction
 
                // Delete a row with a single DELETE without holding row locks over RTTs...
-               $dbw->delete( 'job', array( 'job_cmd' => $this->type, 'job_id' => $job->getId() ) );
+               $dbw->delete( 'job',
+                       array( 'job_cmd' => $this->type, 'job_id' => $job->getId() ), __METHOD__ );
 
                return true;
        }
 
        /**
         * @see JobQueue::doDeduplicateRootJob()
+        * @param Job $job
+        * @throws MWException
         * @return bool
         */
        protected function doDeduplicateRootJob( Job $job ) {
@@ -392,7 +405,7 @@ class JobQueueDB extends JobQueue {
                $key = $this->getRootJobCacheKey( $params['rootJobSignature'] );
                // Callers should call batchInsert() and then this function so that if the insert
                // fails, the de-duplication registration will be aborted. Since the insert is
-               // deferred till "transaction idle", do that same here, so that the ordering is
+               // deferred till "transaction idle", do the same here, so that the ordering is
                // maintained. Having only the de-duplication registration succeed would cause
                // jobs to become no-ops without any actual jobs that made them redundant.
                $this->getMasterDB()->onTransactionIdle( function() use ( $params, $key ) {