--- /dev/null
+<?php
+/**
+ * Database-backed job queue code.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+use Wikimedia\Rdbms\IDatabase;
+use Wikimedia\Rdbms\DBConnRef;
+use Wikimedia\Rdbms\DBConnectionError;
+use Wikimedia\Rdbms\DBError;
+use MediaWiki\MediaWikiServices;
+use Wikimedia\ScopedCallback;
+
+/**
+ * Class to handle job queues stored in the DB
+ *
+ * @ingroup JobQueue
+ * @since 1.21
+ */
+class JobQueueDB extends JobQueue {
+ const CACHE_TTL_SHORT = 30; // integer; seconds to cache info without re-validating
+ const MAX_AGE_PRUNE = 604800; // integer; seconds a job can live once claimed
+ const MAX_JOB_RANDOM = 2147483647; // integer; 2^31 - 1, used for job_random
+ const MAX_OFFSET = 255; // integer; maximum number of rows to skip
+
+ /** @var WANObjectCache */
+ protected $cache;
+
+ /** @var bool|string Name of an external DB cluster. False if not set */
+ protected $cluster = false;
+
+ /**
+ * Additional parameters include:
+ * - cluster : The name of an external cluster registered via LBFactory.
+ * If not specified, the primary DB cluster for the wiki will be used.
+ * This can be overridden with a custom cluster so that DB handles will
+ * be retrieved via LBFactory::getExternalLB() and getConnection().
+ * @param array $params
+ */
+ protected function __construct( array $params ) {
+ parent::__construct( $params );
+
+ $this->cluster = isset( $params['cluster'] ) ? $params['cluster'] : false;
+ $this->cache = ObjectCache::getMainWANInstance();
+ }
+
+ protected function supportedOrders() {
+ return [ 'random', 'timestamp', 'fifo' ];
+ }
+
+ protected function optimalOrder() {
+ return 'random';
+ }
+
+ /**
+ * @see JobQueue::doIsEmpty()
+ * @return bool
+ */
+ protected function doIsEmpty() {
+ $dbr = $this->getReplicaDB();
+ try {
+ $found = $dbr->selectField( // unclaimed job
+ 'job', '1', [ 'job_cmd' => $this->type, 'job_token' => '' ], __METHOD__
+ );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+
+ return !$found;
+ }
+
+ /**
+ * @see JobQueue::doGetSize()
+ * @return int
+ */
+ protected function doGetSize() {
+ $key = $this->getCacheKey( 'size' );
+
+ $size = $this->cache->get( $key );
+ if ( is_int( $size ) ) {
+ return $size;
+ }
+
+ try {
+ $dbr = $this->getReplicaDB();
+ $size = (int)$dbr->selectField( 'job', 'COUNT(*)',
+ [ 'job_cmd' => $this->type, 'job_token' => '' ],
+ __METHOD__
+ );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+ $this->cache->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->cache->get( $key );
+ if ( is_int( $count ) ) {
+ return $count;
+ }
+
+ $dbr = $this->getReplicaDB();
+ try {
+ $count = (int)$dbr->selectField( 'job', 'COUNT(*)',
+ [ 'job_cmd' => $this->type, "job_token != {$dbr->addQuotes( '' )}" ],
+ __METHOD__
+ );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+ $this->cache->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->cache->get( $key );
+ if ( is_int( $count ) ) {
+ return $count;
+ }
+
+ $dbr = $this->getReplicaDB();
+ 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 ) {
+ $this->throwDBException( $e );
+ }
+
+ $this->cache->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();
+ // 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_AUTO 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 () use ( $dbw, $jobs, $flags, $fname ) {
+ $this->doBatchPushInternal( $dbw, $jobs, $flags, $fname );
+ },
+ $fname
+ );
+ }
+
+ /**
+ * This function should *not* be called outside of JobQueueDB
+ *
+ * @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 ( !count( $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 );
+ 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_keys( $rowSet ),
+ 'job_token' => '' // unclaimed
+ ],
+ $method
+ );
+ foreach ( $res as $row ) {
+ wfDebug( "Job with hash '{$row->job_sha1}' is a duplicate.\n" );
+ 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 );
+ }
+ JobQueue::incrStats( 'inserts', $this->type, count( $rows ) );
+ JobQueue::incrStats( 'dupe_inserts', $this->type,
+ count( $rowSet ) + count( $rowList ) - count( $rows )
+ );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+ if ( $flags & self::QOS_ATOMIC ) {
+ $dbw->endAtomic( $method );
+ }
+
+ return;
+ }
+
+ /**
+ * @see JobQueue::doPop()
+ * @return Job|bool
+ */
+ protected function doPop() {
+ $dbw = $this->getMasterDB();
+ try {
+ $autoTrx = $dbw->getFlag( DBO_TRX ); // get current setting
+ $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
+ $scopedReset = new ScopedCallback( function () use ( $dbw, $autoTrx ) {
+ $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore old setting
+ } );
+
+ $uuid = wfRandomString( 32 ); // pop attempt
+ $job = false; // job popped off
+ 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
+ }
+ JobQueue::incrStats( 'pops', $this->type );
+ // Get the job object from the row...
+ $title = Title::makeTitle( $row->job_namespace, $row->job_title );
+ $job = Job::factory( $row->job_cmd, $title,
+ self::extractBlob( $row->job_params ), $row->job_id );
+ $job->metadata['id'] = $row->job_id;
+ $job->metadata['timestamp'] = $row->job_timestamp;
+ break; // done
+ } while ( true );
+
+ if ( !$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 ) {
+ $this->throwDBException( $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();
+ // Check cache to see if the queue has <= OFFSET items
+ $tinyQueue = $this->cache->get( $this->getCacheKey( 'small' ) );
+
+ $row = false; // the row acquired
+ $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->cache->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();
+
+ $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).
+ // Oracle and Postgre have 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.\n" );
+ }
+ } else {
+ break; // nothing to do
+ }
+ } while ( !$row );
+
+ return $row;
+ }
+
+ /**
+ * @see JobQueue::doAck()
+ * @param Job $job
+ * @throws MWException
+ */
+ protected function doAck( Job $job ) {
+ if ( !isset( $job->metadata['id'] ) ) {
+ throw new MWException( "Job of type '{$job->getType()}' has no ID." );
+ }
+
+ $dbw = $this->getMasterDB();
+ try {
+ $autoTrx = $dbw->getFlag( DBO_TRX ); // get current setting
+ $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
+ $scopedReset = new ScopedCallback( function () use ( $dbw, $autoTrx ) {
+ $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore old setting
+ } );
+
+ // Delete a row with a single DELETE without holding row locks over RTTs...
+ $dbw->delete( 'job',
+ [ 'job_cmd' => $this->type, 'job_id' => $job->metadata['id'] ], __METHOD__ );
+
+ JobQueue::incrStats( 'acks', $this->type );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+ }
+
+ /**
+ * @see JobQueue::doDeduplicateRootJob()
+ * @param IJobSpecification $job
+ * @throws MWException
+ * @return bool
+ */
+ protected function doDeduplicateRootJob( IJobSpecification $job ) {
+ $params = $job->getParams();
+ if ( !isset( $params['rootJobSignature'] ) ) {
+ throw new MWException( "Cannot register root job; missing 'rootJobSignature'." );
+ } elseif ( !isset( $params['rootJobTimestamp'] ) ) {
+ throw new MWException( "Cannot register root job; missing 'rootJobTimestamp'." );
+ }
+ $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 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();
+ $cache = $this->dupCache;
+ $dbw->onTransactionIdle(
+ function () use ( $cache, $params, $key, $dbw ) {
+ $timestamp = $cache->get( $key ); // current last timestamp of this job
+ if ( $timestamp && $timestamp >= $params['rootJobTimestamp'] ) {
+ return true; // a newer version of this root job was enqueued
+ }
+
+ // Update the timestamp of the last root job started at the location...
+ return $cache->set( $key, $params['rootJobTimestamp'], JobQueueDB::ROOTJOB_TTL );
+ },
+ __METHOD__
+ );
+
+ return true;
+ }
+
+ /**
+ * @see JobQueue::doDelete()
+ * @return bool
+ */
+ protected function doDelete() {
+ $dbw = $this->getMasterDB();
+ try {
+ $dbw->delete( 'job', [ 'job_cmd' => $this->type ] );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+
+ return true;
+ }
+
+ /**
+ * @see JobQueue::doWaitForBackups()
+ * @return void
+ */
+ protected function doWaitForBackups() {
+ $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
+ $lbFactory->waitForReplication( [ 'wiki' => $this->wiki, 'cluster' => $this->cluster ] );
+ }
+
+ /**
+ * @return void
+ */
+ protected function doFlushCaches() {
+ foreach ( [ 'size', 'acquiredcount' ] as $type ) {
+ $this->cache->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();
+ try {
+ return new MappedIterator(
+ $dbr->select( 'job', self::selectFields(), $conds ),
+ function ( $row ) {
+ $job = Job::factory(
+ $row->job_cmd,
+ Title::makeTitle( $row->job_namespace, $row->job_title ),
+ strlen( $row->job_params ) ? unserialize( $row->job_params ) : []
+ );
+ $job->metadata['id'] = $row->job_id;
+ $job->metadata['timestamp'] = $row->job_timestamp;
+
+ return $job;
+ }
+ );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+ }
+
+ public function getCoalesceLocationInternal() {
+ return $this->cluster
+ ? "DBCluster:{$this->cluster}:{$this->wiki}"
+ : "LBFactory:{$this->wiki}";
+ }
+
+ protected function doGetSiblingQueuesWithJobs( array $types ) {
+ $dbr = $this->getReplicaDB();
+ // @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();
+ $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 = $this->getMasterDB();
+
+ try {
+ if ( !$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 ],
+ __METHOD__
+ );
+ $affected = $dbw->affectedRows();
+ $count += $affected;
+ JobQueue::incrStats( 'recycles', $this->type, $affected );
+ $this->aggr->notifyQueueNonEmpty( $this->wiki, $this->type );
+ }
+ }
+
+ // 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;
+ JobQueue::incrStats( 'abandons', $this->type, $affected );
+ }
+
+ $dbw->unlock( "jobqueue-recycle-{$this->type}", __METHOD__ );
+ } catch ( DBError $e ) {
+ $this->throwDBException( $e );
+ }
+
+ return $count;
+ }
+
+ /**
+ * @param IJobSpecification $job
+ * @return array
+ */
+ protected function insertFields( IJobSpecification $job ) {
+ $dbw = $this->getMasterDB();
+
+ return [
+ // Fields that describe the nature of the job
+ 'job_cmd' => $job->getType(),
+ 'job_namespace' => $job->getTitle()->getNamespace(),
+ 'job_title' => $job->getTitle()->getDBkey(),
+ 'job_params' => self::makeBlob( $job->getParams() ),
+ // Additional job metadata
+ 'job_timestamp' => $dbw->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 DBConnRef
+ */
+ protected function getReplicaDB() {
+ try {
+ return $this->getDB( DB_REPLICA );
+ } catch ( DBConnectionError $e ) {
+ throw new JobQueueConnectionError( "DBConnectionError:" . $e->getMessage() );
+ }
+ }
+
+ /**
+ * @throws JobQueueConnectionError
+ * @return DBConnRef
+ */
+ 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 DBConnRef
+ */
+ protected function getDB( $index ) {
+ $lbFactory = MediaWikiServices::getInstance()->getDBLoadBalancerFactory();
+ $lb = ( $this->cluster !== false )
+ ? $lbFactory->getExternalLB( $this->cluster )
+ : $lbFactory->getMainLB( $this->wiki );
+
+ return ( $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.
+ ? $lb->getConnectionRef( $index, [], $this->wiki, $lb::CONN_TRX_AUTO )
+ // Jobs insertion will be defered until the PRESEND stage to reduce contention.
+ : $lb->getConnectionRef( $index, [], $this->wiki );
+ }
+
+ /**
+ * @param string $property
+ * @return string
+ */
+ private function getCacheKey( $property ) {
+ list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
+ $cluster = is_string( $this->cluster ) ? $this->cluster : 'main';
+
+ return wfForeignMemcKey( $db, $prefix, 'jobqueue', $cluster, $this->type, $property );
+ }
+
+ /**
+ * @param array|bool $params
+ * @return string
+ */
+ protected static function makeBlob( $params ) {
+ if ( $params !== false ) {
+ return serialize( $params );
+ } else {
+ return '';
+ }
+ }
+
+ /**
+ * @param string $blob
+ * @return bool|mixed
+ */
+ protected static function extractBlob( $blob ) {
+ if ( (string)$blob !== '' ) {
+ return unserialize( $blob );
+ } else {
+ return false;
+ }
+ }
+
+ /**
+ * @param DBError $e
+ * @throws JobQueueError
+ */
+ protected function throwDBException( DBError $e ) {
+ throw 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',
+ ];
+ }
+}
scripts.mit.edu / autoinstallsdev / mediawiki.git / blobdiff