* @since 1.21
*/
class JobQueueDB extends JobQueue {
- const CACHE_TTL = 300; // integer; seconds
- const MAX_JOB_RANDOM = 2147483647; // 2^31 - 1; used for job_random
+ const CACHE_TTL = 300; // integer; seconds to cache queue information
+ const MAX_AGE_PRUNE = 604800; // integer; seconds a job can live once claimed
+ const MAX_ATTEMPTS = 3; // integer; number of times to try a job
+ const MAX_JOB_RANDOM = 2147483647; // integer; 2^31 - 1, used for job_random
/**
* @see JobQueue::doIsEmpty()
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, $found ? 'false' : 'true', self::CACHE_TTL );
+ return (bool)$found;
}
/**
* @see JobQueue::doBatchPush()
+ * @param array $jobs
+ * @param $flags
+ * @throws DBError|Exception
* @return bool
*/
protected function doBatchPush( array $jobs, $flags ) {
if ( count( $jobs ) ) {
$dbw = $this->getMasterDB();
- $rows = array();
+ $rowSet = array(); // (sha1 => job) map for jobs that are de-duplicated
+ $rowList = array(); // list of jobs for jobs that are are not de-duplicated
+
foreach ( $jobs as $job ) {
- $rows[] = $this->insertFields( $job );
+ $row = $this->insertFields( $job );
+ if ( $job->ignoreDuplicates() ) {
+ $rowSet[$row['job_sha1']] = $row;
+ } else {
+ $rowList[] = $row;
+ }
}
+
$atomic = ( $flags & self::QoS_Atomic );
$key = $this->getEmptinessCacheKey();
$ttl = self::CACHE_TTL;
- $dbw->onTransactionIdle( function() use ( $dbw, $rows, $atomic, $key, $ttl ) {
+ $dbw->onTransactionIdle(
+ function() use ( $dbw, $rowSet, $rowList, $atomic, $key, $ttl
+ ) {
global $wgMemc;
- $autoTrx = $dbw->getFlag( DBO_TRX ); // automatic begin() enabled?
if ( $atomic ) {
- $dbw->begin(); // wrap all the job additions in one transaction
- } else {
- $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
+ $dbw->begin( __METHOD__ ); // wrap all the job additions in one transaction
}
try {
- foreach ( array_chunk( $rows, 50 ) as $rowBatch ) { // avoid slave lag
+ // Strip out any duplicate jobs that are already in the queue...
+ if ( count( $rowSet ) ) {
+ $res = $dbw->select( 'job', 'job_sha1',
+ array(
+ // 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." );
+ 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 slave lag...
+ foreach ( array_chunk( $rows, 50 ) as $rowBatch ) {
$dbw->insert( 'job', $rowBatch, __METHOD__ );
}
} catch ( DBError $e ) {
if ( $atomic ) {
- $dbw->rollback();
- } else {
- $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
+ $dbw->rollback( __METHOD__ );
}
throw $e;
}
if ( $atomic ) {
- $dbw->commit();
- } else {
- $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
+ $dbw->commit( __METHOD__ );
}
$wgMemc->set( $key, 'false', $ttl ); // queue is not empty
$uuid = wfRandomString( 32 ); // pop attempt
$job = false; // job popped off
- $autoTrx = $dbw->getFlag( DBO_TRX ); // automatic begin() enabled?
- $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
- try {
- do { // retry when our row is invalid or deleted as a duplicate
- // Try to reserve a row in the DB...
- if ( $this->order === 'timestamp' ) { // oldest first
- $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, $gte );
- if ( !$row ) { // need to try the other direction
- $row = $this->claimRandom( $uuid, $rand, !$gte );
- }
- }
- // Check if we found a row to reserve...
- if ( !$row ) {
- $wgMemc->set( $this->getEmptinessCacheKey(), 'true', self::CACHE_TTL );
- break; // nothing to do
- }
- // Get the job object from the row...
- $title = Title::makeTitleSafe( $row->job_namespace, $row->job_title );
- if ( !$title ) {
- $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
- wfIncrStats( 'job-pop' );
- wfDebugLog( 'JobQueueDB', "Row has invalid title '{$row->job_title}'." );
- continue; // try again
- }
- $job = Job::factory( $row->job_cmd, $title,
- self::extractBlob( $row->job_params ), $row->job_id );
- // Delete any *other* duplicate jobs in the queue...
- if ( $job->ignoreDuplicates() && strlen( $row->job_sha1 ) ) {
- $dbw->delete( 'job',
- array( 'job_sha1' => $row->job_sha1,
- "job_id != {$dbw->addQuotes( $row->job_id )}" ),
- __METHOD__
- );
- wfIncrStats( 'job-pop', $dbw->affectedRows() );
- }
- break; // done
- } while( true );
- } catch ( DBError $e ) {
- $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
- throw $e;
+ // Occasionally recycle jobs back into the queue that have been claimed too long
+ if ( mt_rand( 0, 99 ) == 0 ) {
+ $this->recycleStaleJobs();
}
- $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
+ 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, array( '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, $gte );
+ if ( !$row ) { // need to try the other direction
+ $row = $this->claimRandom( $uuid, $rand, !$gte );
+ }
+ }
+ // Check if we found a row to reserve...
+ if ( !$row ) {
+ $wgMemc->set( $this->getEmptinessCacheKey(), 'true', self::CACHE_TTL );
+ break; // nothing to do
+ }
+ // Get the job object from the row...
+ $title = Title::makeTitleSafe( $row->job_namespace, $row->job_title );
+ if ( !$title ) {
+ $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
+ wfIncrStats( 'job-pop' );
+ wfDebugLog( 'JobQueueDB', "Row has invalid title '{$row->job_title}'." );
+ continue; // try again
+ }
+ $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
+ }
+ break; // done
+ } while( true );
return $job;
}
);
if ( $row ) { // claim the job
$dbw->update( 'job', // update by PK
- array( 'job_token' => $uuid, 'job_token_timestamp' => $dbw->timestamp() ),
+ array(
+ 'job_token' => $uuid,
+ 'job_token_timestamp' => $dbw->timestamp(),
+ 'job_attempts = job_attempts+1' ),
array( 'job_cmd' => $this->type, 'job_id' => $row->job_id, 'job_token' => '' ),
__METHOD__
);
// 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( $dbw->timestamp() )}
- WHERE (
- job_cmd = {$dbw->addQuotes( $this->type )}
- AND job_token = {$dbw->addQuotes( '' )}
- ) ORDER BY job_random ASC LIMIT 1",
+ $dbw->query( "UPDATE {$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',
- array( 'job_token' => $uuid, 'job_token_timestamp' => $dbw->timestamp() ),
+ array(
+ 'job_token' => $uuid,
+ 'job_token_timestamp' => $dbw->timestamp(),
+ 'job_attempts = job_attempts+1' ),
array( 'job_id = (' .
$dbw->selectSQLText( 'job', 'job_id',
array( 'job_cmd' => $this->type, 'job_token' => '' ),
__METHOD__,
- array( 'ORDER BY' => 'job_random ASC', 'LIMIT' => 1 ) ) .
+ array( 'ORDER BY' => 'job_id ASC', 'LIMIT' => 1 ) ) .
')'
),
__METHOD__
return $row;
}
+ /**
+ * Recycle or destroy any jobs that have been claimed for too long
+ *
+ * @return integer Number of jobs recycled/deleted
+ */
+ protected function recycleStaleJobs() {
+ $now = time();
+ $dbw = $this->getMasterDB();
+ $count = 0; // affected rows
+
+ if ( !$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',
+ array(
+ 'job_cmd' => $this->type,
+ "job_token != {$dbw->addQuotes( '' )}", // was acquired
+ "job_token_timestamp < {$dbw->addQuotes( $claimCutoff )}", // stale
+ "job_attempts < {$dbw->addQuotes( self::MAX_ATTEMPTS )}" ), // 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',
+ array(
+ 'job_token' => '',
+ 'job_token_timestamp' => $dbw->timestamp( $now ) ), // time of release
+ array(
+ 'job_id' => $ids ),
+ __METHOD__
+ );
+ $count += $dbw->affectedRows();
+ }
+ }
+
+ // Just destroy any stale jobs...
+ $pruneCutoff = $dbw->timestamp( $now - self::MAX_AGE_PRUNE );
+ $conds = array(
+ '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( self::MAX_ATTEMPTS )}";
+ }
+ // 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', array( 'job_id' => $ids ), __METHOD__ );
+ $count += $dbw->affectedRows();
+ }
+
+ $dbw->unlock( "jobqueue-recycle-{$this->type}", __METHOD__ );
+
+ return $count;
+ }
+
/**
* @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
- $autoTrx = $dbw->getFlag( DBO_TRX ); // automatic begin() enabled?
- $dbw->clearFlag( DBO_TRX ); // make each query its own transaction
- try {
- // 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() ) );
- } catch ( Exception $e ) {
- $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
- throw $e;
+ // 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() ), __METHOD__ );
+
+ return true;
+ }
+
+ /**
+ * @see JobQueue::doDeduplicateRootJob()
+ * @param Job $job
+ * @throws MWException
+ * @return bool
+ */
+ protected function doDeduplicateRootJob( Job $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'." );
}
- $dbw->setFlag( $autoTrx ? DBO_TRX : 0 ); // restore automatic begin()
+ $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
+ // 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 ) {
+ global $wgMemc;
+
+ $timestamp = $wgMemc->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 $wgMemc->set( $key, $params['rootJobTimestamp'], 14*86400 ); // 2 weeks
+ } );
return true;
}
+ /**
+ * Check if the "root" job of a given job has been superseded by a newer one
+ *
+ * @param $job Job
+ * @return bool
+ */
+ protected function isRootJobOldDuplicate( Job $job ) {
+ global $wgMemc;
+
+ $params = $job->getParams();
+ if ( !isset( $params['rootJobSignature'] ) ) {
+ return false; // job has no de-deplication info
+ } elseif ( !isset( $params['rootJobTimestamp'] ) ) {
+ trigger_error( "Cannot check root job; missing 'rootJobTimestamp'." );
+ return false;
+ }
+
+ // Get the last time this root job was enqueued
+ $timestamp = $wgMemc->get( $this->getRootJobCacheKey( $params['rootJobSignature'] ) );
+
+ // Check if a new root job was started at the location after this one's...
+ return ( $timestamp && $timestamp > $params['rootJobTimestamp'] );
+ }
+
/**
* @see JobQueue::doWaitForBackups()
* @return void
* @return array
*/
protected function insertFields( Job $job ) {
- // Rows that describe the nature of the job
- $descFields = array(
+ $dbw = $this->getMasterDB();
+ return array(
+ // 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
- if ( $this->order === 'timestamp' ) { // oldest first
- $random = time() - 1325376000; // seconds since "January 1, 2012"
- } else { // random first
- $random = mt_rand( 0, self::MAX_JOB_RANDOM );
- }
- $dbw = $this->getMasterDB();
- $metaFields = array(
+ // Additional job metadata
'job_id' => $dbw->nextSequenceValue( 'job_job_id_seq' ),
'job_timestamp' => $dbw->timestamp(),
- 'job_sha1' => wfBaseConvert( sha1( serialize( $descFields ) ), 16, 36, 32 ),
- 'job_random' => $random
+ 'job_sha1' => wfBaseConvert(
+ sha1( serialize( $job->getDeduplicationInfo() ) ),
+ 16, 36, 31
+ ),
+ 'job_random' => mt_rand( 0, self::MAX_JOB_RANDOM )
);
- return ( $descFields + $metaFields );
}
/**
return wfForeignMemcKey( $db, $prefix, 'jobqueue', $this->type, 'isempty' );
}
+ /**
+ * @param string $signature Hash identifier of the root job
+ * @return string
+ */
+ private function getRootJobCacheKey( $signature ) {
+ list( $db, $prefix ) = wfSplitWikiID( $this->wiki );
+ return wfForeignMemcKey( $db, $prefix, 'jobqueue', $this->type, 'rootjob', $signature );
+ }
+
/**
* @param $params
* @return string
dépôts / lhc / web / wiklou.git / blobdiff