server = $params['server']; } elseif ( isset( $params['cluster'] ) && is_string( $params['cluster'] ) ) { $this->cluster = $params['cluster']; } } protected function supportedOrders() { return [ 'random', 'timestamp', 'fifo' ]; } protected function optimalOrder() { return 'random'; } /** * @see JobQueue::doIsEmpty() * @return bool */ protected function doIsEmpty() { $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); try { $found = $dbr->selectField( // unclaimed job 'job', '1', [ 'job_cmd' => $this->type, 'job_token' => '' ], __METHOD__ ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } return !$found; } /** * @see JobQueue::doGetSize() * @return int */ protected function doGetSize() { $key = $this->getCacheKey( 'size' ); $size = $this->wanCache->get( $key ); if ( is_int( $size ) ) { return $size; } $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); try { $size = (int)$dbr->selectField( 'job', 'COUNT(*)', [ 'job_cmd' => $this->type, 'job_token' => '' ], __METHOD__ ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } $this->wanCache->set( $key, $size, self::CACHE_TTL_SHORT ); return $size; } /** * @see JobQueue::doGetAcquiredCount() * @return int */ protected function doGetAcquiredCount() { if ( $this->claimTTL <= 0 ) { return 0; // no acknowledgements } $key = $this->getCacheKey( 'acquiredcount' ); $count = $this->wanCache->get( $key ); if ( is_int( $count ) ) { return $count; } $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); try { $count = (int)$dbr->selectField( 'job', 'COUNT(*)', [ 'job_cmd' => $this->type, "job_token != {$dbr->addQuotes( '' )}" ], __METHOD__ ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } $this->wanCache->set( $key, $count, self::CACHE_TTL_SHORT ); return $count; } /** * @see JobQueue::doGetAbandonedCount() * @return int * @throws MWException */ protected function doGetAbandonedCount() { if ( $this->claimTTL <= 0 ) { return 0; // no acknowledgements } $key = $this->getCacheKey( 'abandonedcount' ); $count = $this->wanCache->get( $key ); if ( is_int( $count ) ) { return $count; } $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); try { $count = (int)$dbr->selectField( 'job', 'COUNT(*)', [ 'job_cmd' => $this->type, "job_token != {$dbr->addQuotes( '' )}", "job_attempts >= " . $dbr->addQuotes( $this->maxTries ) ], __METHOD__ ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } $this->wanCache->set( $key, $count, self::CACHE_TTL_SHORT ); return $count; } /** * @see JobQueue::doBatchPush() * @param IJobSpecification[] $jobs * @param int $flags * @throws DBError|Exception * @return void */ protected function doBatchPush( array $jobs, $flags ) { $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); // In general, there will be two cases here: // a) sqlite; DB connection is probably a regular round-aware handle. // If the connection is busy with a transaction, then defer the job writes // until right before the main round commit step. Any errors that bubble // up will rollback the main commit round. // b) mysql/postgres; DB connection is generally a separate CONN_TRX_AUTOCOMMIT handle. // No transaction is active nor will be started by writes, so enqueue the jobs // now so that any errors will show up immediately as the interface expects. Any // errors that bubble up will rollback the main commit round. $fname = __METHOD__; $dbw->onTransactionPreCommitOrIdle( function ( IDatabase $dbw ) use ( $jobs, $flags, $fname ) { $this->doBatchPushInternal( $dbw, $jobs, $flags, $fname ); }, $fname ); } /** * This function should *not* be called outside of JobQueueDB * * @suppress SecurityCheck-SQLInjection Bug in phan-taint-check handling bulk inserts * @param IDatabase $dbw * @param IJobSpecification[] $jobs * @param int $flags * @param string $method * @throws DBError * @return void */ public function doBatchPushInternal( IDatabase $dbw, array $jobs, $flags, $method ) { if ( $jobs === [] ) { return; } $rowSet = []; // (sha1 => job) map for jobs that are de-duplicated $rowList = []; // list of jobs for jobs that are not de-duplicated foreach ( $jobs as $job ) { $row = $this->insertFields( $job, $dbw ); if ( $job->ignoreDuplicates() ) { $rowSet[$row['job_sha1']] = $row; } else { $rowList[] = $row; } } if ( $flags & self::QOS_ATOMIC ) { $dbw->startAtomic( $method ); // wrap all the job additions in one transaction } try { // Strip out any duplicate jobs that are already in the queue... if ( count( $rowSet ) ) { $res = $dbw->select( 'job', 'job_sha1', [ // No job_type condition since it's part of the job_sha1 hash 'job_sha1' => array_map( 'strval', array_keys( $rowSet ) ), 'job_token' => '' // unclaimed ], $method ); foreach ( $res as $row ) { wfDebug( "Job with hash '{$row->job_sha1}' is a duplicate." ); unset( $rowSet[$row->job_sha1] ); // already enqueued } } // Build the full list of job rows to insert $rows = array_merge( $rowList, array_values( $rowSet ) ); // Insert the job rows in chunks to avoid replica DB lag... foreach ( array_chunk( $rows, 50 ) as $rowBatch ) { $dbw->insert( 'job', $rowBatch, $method ); } $this->incrStats( 'inserts', $this->type, count( $rows ) ); $this->incrStats( 'dupe_inserts', $this->type, count( $rowSet ) + count( $rowList ) - count( $rows ) ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } if ( $flags & self::QOS_ATOMIC ) { $dbw->endAtomic( $method ); } } /** * @see JobQueue::doPop() * @return RunnableJob|bool */ protected function doPop() { $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); $job = false; // job popped off try { $uuid = wfRandomString( 32 ); // pop attempt do { // retry when our row is invalid or deleted as a duplicate // Try to reserve a row in the DB... if ( in_array( $this->order, [ 'fifo', 'timestamp' ] ) ) { $row = $this->claimOldest( $uuid ); } else { // random first $rand = mt_rand( 0, self::MAX_JOB_RANDOM ); // encourage concurrent UPDATEs $gte = (bool)mt_rand( 0, 1 ); // find rows with rand before/after $rand $row = $this->claimRandom( $uuid, $rand, $gte ); } // Check if we found a row to reserve... if ( !$row ) { break; // nothing to do } $this->incrStats( 'pops', $this->type ); // Get the job object from the row... $job = $this->jobFromRow( $row ); break; // done } while ( true ); if ( !$job || mt_rand( 0, 9 ) == 0 ) { // Handled jobs that need to be recycled/deleted; // any recycled jobs will be picked up next attempt $this->recycleAndDeleteStaleJobs(); } } catch ( DBError $e ) { throw $this->getDBException( $e ); } return $job; } /** * Reserve a row with a single UPDATE without holding row locks over RTTs... * * @param string $uuid 32 char hex string * @param int $rand Random unsigned integer (31 bits) * @param bool $gte Search for job_random >= $random (otherwise job_random <= $random) * @return stdClass|bool Row|false */ protected function claimRandom( $uuid, $rand, $gte ) { $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); // Check cache to see if the queue has <= OFFSET items $tinyQueue = $this->wanCache->get( $this->getCacheKey( 'small' ) ); $invertedDirection = false; // whether one job_random direction was already scanned // This uses a replication safe method for acquiring jobs. One could use UPDATE+LIMIT // instead, but that either uses ORDER BY (in which case it deadlocks in MySQL) or is // not replication safe. Due to https://bugs.mysql.com/bug.php?id=6980, subqueries cannot // be used here with MySQL. do { if ( $tinyQueue ) { // queue has <= MAX_OFFSET rows // For small queues, using OFFSET will overshoot and return no rows more often. // Instead, this uses job_random to pick a row (possibly checking both directions). $ineq = $gte ? '>=' : '<='; $dir = $gte ? 'ASC' : 'DESC'; $row = $dbw->selectRow( 'job', self::selectFields(), // find a random job [ 'job_cmd' => $this->type, 'job_token' => '', // unclaimed "job_random {$ineq} {$dbw->addQuotes( $rand )}" ], __METHOD__, [ 'ORDER BY' => "job_random {$dir}" ] ); if ( !$row && !$invertedDirection ) { $gte = !$gte; $invertedDirection = true; continue; // try the other direction } } else { // table *may* have >= MAX_OFFSET rows // T44614: "ORDER BY job_random" with a job_random inequality causes high CPU // in MySQL if there are many rows for some reason. This uses a small OFFSET // instead of job_random for reducing excess claim retries. $row = $dbw->selectRow( 'job', self::selectFields(), // find a random job [ 'job_cmd' => $this->type, 'job_token' => '', // unclaimed ], __METHOD__, [ 'OFFSET' => mt_rand( 0, self::MAX_OFFSET ) ] ); if ( !$row ) { $tinyQueue = true; // we know the queue must have <= MAX_OFFSET rows $this->wanCache->set( $this->getCacheKey( 'small' ), 1, 30 ); continue; // use job_random } } if ( $row ) { // claim the job $dbw->update( 'job', // update by PK [ 'job_token' => $uuid, 'job_token_timestamp' => $dbw->timestamp(), 'job_attempts = job_attempts+1' ], [ 'job_cmd' => $this->type, 'job_id' => $row->job_id, 'job_token' => '' ], __METHOD__ ); // This might get raced out by another runner when claiming the previously // selected row. The use of job_random should minimize this problem, however. if ( !$dbw->affectedRows() ) { $row = false; // raced out } } else { break; // nothing to do } } while ( !$row ); return $row; } /** * Reserve a row with a single UPDATE without holding row locks over RTTs... * * @param string $uuid 32 char hex string * @return stdClass|bool Row|false */ protected function claimOldest( $uuid ) { $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); $row = false; // the row acquired do { if ( $dbw->getType() === 'mysql' ) { // Per https://bugs.mysql.com/bug.php?id=6980, we can't use subqueries on the // same table being changed in an UPDATE query in MySQL (gives Error: 1093). // Postgres has no such limitation. However, MySQL offers an // alternative here by supporting ORDER BY + LIMIT for UPDATE queries. $dbw->query( "UPDATE {$dbw->tableName( 'job' )} " . "SET " . "job_token = {$dbw->addQuotes( $uuid ) }, " . "job_token_timestamp = {$dbw->addQuotes( $dbw->timestamp() )}, " . "job_attempts = job_attempts+1 " . "WHERE ( " . "job_cmd = {$dbw->addQuotes( $this->type )} " . "AND job_token = {$dbw->addQuotes( '' )} " . ") ORDER BY job_id ASC LIMIT 1", __METHOD__ ); } else { // Use a subquery to find the job, within an UPDATE to claim it. // This uses as much of the DB wrapper functions as possible. $dbw->update( 'job', [ 'job_token' => $uuid, 'job_token_timestamp' => $dbw->timestamp(), 'job_attempts = job_attempts+1' ], [ 'job_id = (' . $dbw->selectSQLText( 'job', 'job_id', [ 'job_cmd' => $this->type, 'job_token' => '' ], __METHOD__, [ 'ORDER BY' => 'job_id ASC', 'LIMIT' => 1 ] ) . ')' ], __METHOD__ ); } // Fetch any row that we just reserved... if ( $dbw->affectedRows() ) { $row = $dbw->selectRow( 'job', self::selectFields(), [ 'job_cmd' => $this->type, 'job_token' => $uuid ], __METHOD__ ); if ( !$row ) { // raced out by duplicate job removal wfDebug( "Row deleted as duplicate by another process." ); } } else { break; // nothing to do } } while ( !$row ); return $row; } /** * @see JobQueue::doAck() * @param RunnableJob $job * @throws MWException */ protected function doAck( RunnableJob $job ) { $id = $job->getMetadata( 'id' ); if ( $id === null ) { throw new MWException( "Job of type '{$job->getType()}' has no ID." ); } $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); try { // Delete a row with a single DELETE without holding row locks over RTTs... $dbw->delete( 'job', [ 'job_cmd' => $this->type, 'job_id' => $id ], __METHOD__ ); $this->incrStats( 'acks', $this->type ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } } /** * @see JobQueue::doDeduplicateRootJob() * @param IJobSpecification $job * @throws MWException * @return bool */ protected function doDeduplicateRootJob( IJobSpecification $job ) { // Callers should call JobQueueGroup::push() before this method so that if the // insert fails, the de-duplication registration will be aborted. Since the insert // 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. $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); $dbw->onTransactionCommitOrIdle( function () use ( $job ) { parent::doDeduplicateRootJob( $job ); }, __METHOD__ ); return true; } /** * @see JobQueue::doDelete() * @return bool */ protected function doDelete() { $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); try { $dbw->delete( 'job', [ 'job_cmd' => $this->type ], __METHOD__ ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } return true; } /** * @see JobQueue::doWaitForBackups() * @return void */ protected function doWaitForBackups() { if ( $this->server ) { return; // not using LBFactory instance } $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory(); $lbFactory->waitForReplication( [ 'domain' => $this->domain, 'cluster' => is_string( $this->cluster ) ? $this->cluster : false ] ); } /** * @return void */ protected function doFlushCaches() { foreach ( [ 'size', 'acquiredcount' ] as $type ) { $this->wanCache->delete( $this->getCacheKey( $type ) ); } } /** * @see JobQueue::getAllQueuedJobs() * @return Iterator */ public function getAllQueuedJobs() { return $this->getJobIterator( [ 'job_cmd' => $this->getType(), 'job_token' => '' ] ); } /** * @see JobQueue::getAllAcquiredJobs() * @return Iterator */ public function getAllAcquiredJobs() { return $this->getJobIterator( [ 'job_cmd' => $this->getType(), "job_token > ''" ] ); } /** * @param array $conds Query conditions * @return Iterator */ protected function getJobIterator( array $conds ) { $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); try { return new MappedIterator( $dbr->select( 'job', self::selectFields(), $conds, __METHOD__ ), function ( $row ) { return $this->jobFromRow( $row ); } ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } } public function getCoalesceLocationInternal() { if ( $this->server ) { return null; // not using the LBFactory instance } return is_string( $this->cluster ) ? "DBCluster:{$this->cluster}:{$this->domain}" : "LBFactory:{$this->domain}"; } protected function doGetSiblingQueuesWithJobs( array $types ) { $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); // @note: this does not check whether the jobs are claimed or not. // This is useful so JobQueueGroup::pop() also sees queues that only // have stale jobs. This lets recycleAndDeleteStaleJobs() re-enqueue // failed jobs so that they can be popped again for that edge case. $res = $dbr->select( 'job', 'DISTINCT job_cmd', [ 'job_cmd' => $types ], __METHOD__ ); $types = []; foreach ( $res as $row ) { $types[] = $row->job_cmd; } return $types; } protected function doGetSiblingQueueSizes( array $types ) { $dbr = $this->getReplicaDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbr ); $res = $dbr->select( 'job', [ 'job_cmd', 'COUNT(*) AS count' ], [ 'job_cmd' => $types ], __METHOD__, [ 'GROUP BY' => 'job_cmd' ] ); $sizes = []; foreach ( $res as $row ) { $sizes[$row->job_cmd] = (int)$row->count; } return $sizes; } /** * Recycle or destroy any jobs that have been claimed for too long * * @return int Number of jobs recycled/deleted */ public function recycleAndDeleteStaleJobs() { $now = time(); $count = 0; // affected rows $dbw = $this->getMasterDB(); /** @noinspection PhpUnusedLocalVariableInspection */ $scope = $this->getScopedNoTrxFlag( $dbw ); try { if ( !$dbw->lock( "jobqueue-recycle-{$this->type}", __METHOD__, 1 ) ) { return $count; // already in progress } // Remove claims on jobs acquired for too long if enabled... if ( $this->claimTTL > 0 ) { $claimCutoff = $dbw->timestamp( $now - $this->claimTTL ); // Get the IDs of jobs that have be claimed but not finished after too long. // These jobs can be recycled into the queue by expiring the claim. Selecting // the IDs first means that the UPDATE can be done by primary key (less deadlocks). $res = $dbw->select( 'job', 'job_id', [ 'job_cmd' => $this->type, "job_token != {$dbw->addQuotes( '' )}", // was acquired "job_token_timestamp < {$dbw->addQuotes( $claimCutoff )}", // stale "job_attempts < {$dbw->addQuotes( $this->maxTries )}" ], // retries left __METHOD__ ); $ids = array_map( function ( $o ) { return $o->job_id; }, iterator_to_array( $res ) ); if ( count( $ids ) ) { // Reset job_token for these jobs so that other runners will pick them up. // Set the timestamp to the current time, as it is useful to now that the job // was already tried before (the timestamp becomes the "released" time). $dbw->update( 'job', [ 'job_token' => '', 'job_token_timestamp' => $dbw->timestamp( $now ) // time of release ], [ 'job_id' => $ids, "job_token != ''" ], __METHOD__ ); $affected = $dbw->affectedRows(); $count += $affected; $this->incrStats( 'recycles', $this->type, $affected ); } } // Just destroy any stale jobs... $pruneCutoff = $dbw->timestamp( $now - self::MAX_AGE_PRUNE ); $conds = [ 'job_cmd' => $this->type, "job_token != {$dbw->addQuotes( '' )}", // was acquired "job_token_timestamp < {$dbw->addQuotes( $pruneCutoff )}" // stale ]; if ( $this->claimTTL > 0 ) { // only prune jobs attempted too many times... $conds[] = "job_attempts >= {$dbw->addQuotes( $this->maxTries )}"; } // Get the IDs of jobs that are considered stale and should be removed. Selecting // the IDs first means that the UPDATE can be done by primary key (less deadlocks). $res = $dbw->select( 'job', 'job_id', $conds, __METHOD__ ); $ids = array_map( function ( $o ) { return $o->job_id; }, iterator_to_array( $res ) ); if ( count( $ids ) ) { $dbw->delete( 'job', [ 'job_id' => $ids ], __METHOD__ ); $affected = $dbw->affectedRows(); $count += $affected; $this->incrStats( 'abandons', $this->type, $affected ); } $dbw->unlock( "jobqueue-recycle-{$this->type}", __METHOD__ ); } catch ( DBError $e ) { throw $this->getDBException( $e ); } return $count; } /** * @param IJobSpecification $job * @param IDatabase $db * @return array */ protected function insertFields( IJobSpecification $job, IDatabase $db ) { return [ // Fields that describe the nature of the job 'job_cmd' => $job->getType(), 'job_namespace' => $job->getParams()['namespace'] ?? NS_SPECIAL, 'job_title' => $job->getParams()['title'] ?? '', 'job_params' => self::makeBlob( $job->getParams() ), // Additional job metadata 'job_timestamp' => $db->timestamp(), 'job_sha1' => Wikimedia\base_convert( sha1( serialize( $job->getDeduplicationInfo() ) ), 16, 36, 31 ), 'job_random' => mt_rand( 0, self::MAX_JOB_RANDOM ) ]; } /** * @throws JobQueueConnectionError * @return IDatabase */ protected function getReplicaDB() { try { return $this->getDB( DB_REPLICA ); } catch ( DBConnectionError $e ) { throw new JobQueueConnectionError( "DBConnectionError:" . $e->getMessage() ); } } /** * @throws JobQueueConnectionError * @return IMaintainableDatabase */ protected function getMasterDB() { try { return $this->getDB( DB_MASTER ); } catch ( DBConnectionError $e ) { throw new JobQueueConnectionError( "DBConnectionError:" . $e->getMessage() ); } } /** * @param int $index (DB_REPLICA/DB_MASTER) * @return IMaintainableDatabase */ protected function getDB( $index ) { if ( $this->server ) { if ( $this->conn instanceof IDatabase ) { return $this->conn; } elseif ( $this->conn instanceof DBError ) { throw $this->conn; } try { $this->conn = Database::factory( $this->server['type'], $this->server ); } catch ( DBError $e ) { $this->conn = $e; throw $e; } return $this->conn; } else { $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory(); $lb = is_string( $this->cluster ) ? $lbFactory->getExternalLB( $this->cluster ) : $lbFactory->getMainLB( $this->domain ); if ( $lb->getServerType( $lb->getWriterIndex() ) !== 'sqlite' ) { // Keep a separate connection to avoid contention and deadlocks; // However, SQLite has the opposite behavior due to DB-level locking. $flags = $lb::CONN_TRX_AUTOCOMMIT; } else { // Jobs insertion will be defered until the PRESEND stage to reduce contention. $flags = 0; } return $lb->getMaintenanceConnectionRef( $index, [], $this->domain, $flags ); } } /** * @param IDatabase $db * @return ScopedCallback */ private function getScopedNoTrxFlag( IDatabase $db ) { $autoTrx = $db->getFlag( DBO_TRX ); // get current setting $db->clearFlag( DBO_TRX ); // make each query its own transaction return new ScopedCallback( function () use ( $db, $autoTrx ) { if ( $autoTrx ) { $db->setFlag( DBO_TRX ); // restore old setting } } ); } /** * @param string $property * @return string */ private function getCacheKey( $property ) { $cluster = is_string( $this->cluster ) ? $this->cluster : 'main'; return $this->wanCache->makeGlobalKey( 'jobqueue', $this->domain, $cluster, $this->type, $property ); } /** * @param array|bool $params * @return string */ protected static function makeBlob( $params ) { if ( $params !== false ) { return serialize( $params ); } else { return ''; } } /** * @param stdClass $row * @return RunnableJob|null */ protected function jobFromRow( $row ) { $params = ( (string)$row->job_params !== '' ) ? unserialize( $row->job_params ) : []; if ( !is_array( $params ) ) { // this shouldn't happen throw new UnexpectedValueException( "Could not unserialize job with ID '{$row->job_id}'." ); } $params += [ 'namespace' => $row->job_namespace, 'title' => $row->job_title ]; $job = $this->factoryJob( $row->job_cmd, $params ); $job->setMetadata( 'id', $row->job_id ); $job->setMetadata( 'timestamp', $row->job_timestamp ); return $job; } /** * @param DBError $e * @return JobQueueError */ protected function getDBException( DBError $e ) { return new JobQueueError( get_class( $e ) . ": " . $e->getMessage() ); } /** * Return the list of job fields that should be selected. * @since 1.23 * @return array */ public static function selectFields() { return [ 'job_id', 'job_cmd', 'job_namespace', 'job_title', 'job_timestamp', 'job_params', 'job_random', 'job_attempts', 'job_token', 'job_token_timestamp', 'job_sha1', ]; } }