<?php
+/**
+ * @defgroup JobQueue JobQueue
+ */
if ( !defined( 'MEDIAWIKI' ) ) {
die( "This file is part of MediaWiki, it is not a valid entry point\n" );
}
-require_once('UserMailer.php');
-
/**
* Class to both describe a background job and handle jobs.
+ *
+ * @ingroup JobQueue
*/
abstract class Job {
var $command,
*/
/**
- * Pop a job of a certain type. This tries less hard than pop() to
- * actually find a job; it may be adversely affected by concurrent job
+ * Pop a job of a certain type. This tries less hard than pop() to
+ * actually find a job; it may be adversely affected by concurrent job
* runners.
*/
- static function pop_type($type) {
+ static function pop_type( $type ) {
wfProfilein( __METHOD__ );
$dbw = wfGetDB( DB_MASTER );
+ $row = $dbw->selectRow(
+ 'job',
+ '*',
+ array( 'job_cmd' => $type ),
+ __METHOD__,
+ array( 'LIMIT' => 1 )
+ );
- $row = $dbw->selectRow( 'job', '*', array( 'job_cmd' => $type ), __METHOD__,
- array( 'LIMIT' => 1 ));
-
- if ($row === false) {
+ if ( $row === false ) {
wfProfileOut( __METHOD__ );
return false;
}
$dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
$affected = $dbw->affectedRows();
- if ($affected == 0) {
+ if ( $affected == 0 ) {
wfProfileOut( __METHOD__ );
return false;
}
$job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
$dbw->delete( 'job', $job->insertFields(), __METHOD__ );
- $dbw->immediateCommit();
+ $dbw->commit();
wfProfileOut( __METHOD__ );
return $job;
/**
* Pop a job off the front of the queue
- * @static
- * @param $offset Number of jobs to skip
+ *
+ * @param $offset Integer: Number of jobs to skip
* @return Job or false if there's no jobs
*/
- static function pop($offset=0) {
+ static function pop( $offset = 0 ) {
wfProfileIn( __METHOD__ );
$dbr = wfGetDB( DB_SLAVE );
- /* Get a job from the slave, start with an offset,
+ /* Get a job from the slave, start with an offset,
scan full set afterwards, avoid hitting purged rows
- NB: If random fetch previously was used, offset
- will always be ahead of few entries
+ NB: If random fetch previously was used, offset
+ will always be ahead of few entries
*/
$row = $dbr->selectRow( 'job', '*', "job_id >= ${offset}", __METHOD__,
- array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
+ array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ) );
// Refetching without offset is needed as some of job IDs could have had delayed commits
// and have lower IDs than jobs already executed, blame concurrency :)
//
- if ( $row === false) {
- if ($offset!=0)
+ if ( $row === false ) {
+ if ( $offset != 0 ) {
$row = $dbr->selectRow( 'job', '*', '', __METHOD__,
- array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ));
+ array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ) );
+ }
- if ($row === false ) {
+ if ( $row === false ) {
wfProfileOut( __METHOD__ );
return false;
}
$dbw = wfGetDB( DB_MASTER );
$dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
$affected = $dbw->affectedRows();
- $dbw->immediateCommit();
+ $dbw->commit();
if ( !$affected ) {
// Failed, someone else beat us to it
// Try getting a random row
$row = $dbw->selectRow( 'job', array( 'MIN(job_id) as minjob',
- 'MAX(job_id) as maxjob' ), "job_id >= $offset", __METHOD__ );
+ 'MAX(job_id) as maxjob' ), '1=1', __METHOD__ );
if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) {
// No jobs to get
wfProfileOut( __METHOD__ );
}
// Get the random row
$row = $dbw->selectRow( 'job', '*',
- 'job_id >= ' . mt_rand( $row->minjob, $row->maxjob ), __METHOD__ );
+ 'job_id >= ' . mt_rand( $row->minjob, $row->maxjob ), __METHOD__ );
if ( $row === false ) {
// Random job gone before we got the chance to select it
// Give up
// Delete the random row
$dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ );
$affected = $dbw->affectedRows();
- $dbw->immediateCommit();
+ $dbw->commit();
if ( !$affected ) {
// Random job gone before we exclusively deleted it
$job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), $row->job_id );
// Remove any duplicates it may have later in the queue
+ // Deadlock prone section
+ $dbw->begin();
$dbw->delete( 'job', $job->insertFields(), __METHOD__ );
+ $dbw->commit();
wfProfileOut( __METHOD__ );
return $job;
/**
* Create the appropriate object to handle a specific job
*
- * @param string $command Job command
- * @param Title $title Associated title
- * @param array $params Job parameters
- * @param int $id Job identifier
+ * @param $command String: Job command
+ * @param $title Title: Associated title
+ * @param $params Array: Job parameters
+ * @param $id Int: Job identifier
* @return Job
*/
static function factory( $command, $title, $params = false, $id = 0 ) {
}
throw new MWException( "Invalid job command `{$command}`" );
}
-
+
static function makeBlob( $params ) {
if ( $params !== false ) {
return serialize( $params );
* @param $jobs array of Job objects
*/
static function batchInsert( $jobs ) {
- if( count( $jobs ) ) {
- $dbw = wfGetDB( DB_MASTER );
- $dbw->begin();
- foreach( $jobs as $job ) {
- $rows[] = $job->insertFields();
+ if( !count( $jobs ) ) {
+ return;
+ }
+ $dbw = wfGetDB( DB_MASTER );
+ $rows = array();
+ foreach( $jobs as $job ) {
+ $rows[] = $job->insertFields();
+ if ( count( $rows ) >= 50 ) {
+ # Do a small transaction to avoid slave lag
+ $dbw->begin();
+ $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' );
+ $dbw->commit();
+ $rows = array();
}
+ }
+ if ( $rows ) {
+ $dbw->begin();
$dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' );
$dbw->commit();
}
return;
}
}
- $fields['job_id'] = $dbw->nextSequenceValue( 'job_job_id_seq' );
$dbw->insert( 'job', $fields, __METHOD__ );
}
protected function insertFields() {
+ $dbw = wfGetDB( DB_MASTER );
return array(
+ 'job_id' => $dbw->nextSequenceValue( 'job_job_id_seq' ),
'job_cmd' => $this->command,
'job_namespace' => $this->title->getNamespace(),
'job_title' => $this->title->getDBkey(),
}
}
+ protected function setLastError( $error ) {
+ $this->error = $error;
+ }
+
function getLastError() {
return $this->error;
}
}
-
-?>
\ No newline at end of file