X-Git-Url: https://scripts.mit.edu/gitweb/autoinstallsdev/mediawiki.git/blobdiff_plain/19e297c21b10b1b8a3acad5e73fc71dcb35db44a..6932310fd58ebef145fa01eb76edf7150284d8ea:/includes/job/JobQueue.php diff --git a/includes/job/JobQueue.php b/includes/job/JobQueue.php deleted file mode 100644 index 8eec8215..00000000 --- a/includes/job/JobQueue.php +++ /dev/null @@ -1,344 +0,0 @@ -selectRow( - 'job', - '*', - array( 'job_cmd' => $type ), - __METHOD__, - array( 'LIMIT' => 1 ) - ); - - if ( $row === false ) { - wfProfileOut( __METHOD__ ); - return false; - } - - /* Ensure we "own" this row */ - $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ ); - $affected = $dbw->affectedRows(); - - if ( $affected == 0 ) { - wfProfileOut( __METHOD__ ); - return false; - } - - $namespace = $row->job_namespace; - $dbkey = $row->job_title; - $title = Title::makeTitleSafe( $namespace, $dbkey ); - $job = Job::factory( $row->job_cmd, $title, Job::extractBlob( $row->job_params ), - $row->job_id ); - - $dbw->delete( 'job', $job->insertFields(), __METHOD__ ); - $dbw->commit(); - - wfProfileOut( __METHOD__ ); - return $job; - } - - /** - * Pop a job off the front of the queue - * - * @param $offset Integer: Number of jobs to skip - * @return Job or false if there's no jobs - */ - static function pop( $offset = 0 ) { - wfProfileIn( __METHOD__ ); - - $dbr = wfGetDB( DB_SLAVE ); - - /* 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 - */ - - $row = $dbr->selectRow( 'job', '*', "job_id >= ${offset}", __METHOD__, - 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 ) { - $row = $dbr->selectRow( 'job', '*', '', __METHOD__, - array( 'ORDER BY' => 'job_id', 'LIMIT' => 1 ) ); - } - - if ( $row === false ) { - wfProfileOut( __METHOD__ ); - return false; - } - } - - // Try to delete it from the master - $dbw = wfGetDB( DB_MASTER ); - $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ ); - $affected = $dbw->affectedRows(); - $dbw->commit(); - - if ( !$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' ), '1=1', __METHOD__ ); - if ( $row === false || is_null( $row->minjob ) || is_null( $row->maxjob ) ) { - // No jobs to get - wfProfileOut( __METHOD__ ); - return false; - } - // Get the random row - $row = $dbw->selectRow( 'job', '*', - '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 - wfProfileOut( __METHOD__ ); - return false; - } - // Delete the random row - $dbw->delete( 'job', array( 'job_id' => $row->job_id ), __METHOD__ ); - $affected = $dbw->affectedRows(); - $dbw->commit(); - - if ( !$affected ) { - // Random job gone before we exclusively deleted it - // Give up - wfProfileOut( __METHOD__ ); - return false; - } - } - - // If execution got to here, there's a row in $row that has been deleted from the database - // by this thread. Hence the concurrent pop was successful. - $namespace = $row->job_namespace; - $dbkey = $row->job_title; - $title = Title::makeTitleSafe( $namespace, $dbkey ); - $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 $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 ) { - global $wgJobClasses; - if( isset( $wgJobClasses[$command] ) ) { - $class = $wgJobClasses[$command]; - return new $class( $title, $params, $id ); - } - throw new MWException( "Invalid job command `{$command}`" ); - } - - static function makeBlob( $params ) { - if ( $params !== false ) { - return serialize( $params ); - } else { - return ''; - } - } - - static function extractBlob( $blob ) { - if ( (string)$blob !== '' ) { - return unserialize( $blob ); - } else { - return false; - } - } - - /** - * Batch-insert a group of jobs into the queue. - * This will be wrapped in a transaction with a forced commit. - * - * This may add duplicate at insert time, but they will be - * removed later on, when the first one is popped. - * - * @param $jobs array of Job objects - */ - static function batchInsert( $jobs ) { - 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 ) { // last chunk - $dbw->begin(); - $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' ); - $dbw->commit(); - } - wfIncrStats( 'job-insert', count( $jobs ) ); - } - - /** - * Insert a group of jobs into the queue. - * - * Same as batchInsert() but does not commit and can thus - * be rolled-back as part of a larger transaction. However, - * large batches of jobs can cause slave lag. - * - * @param $jobs array of Job objects - */ - static function safeBatchInsert( $jobs ) { - if ( !count( $jobs ) ) { - return; - } - $dbw = wfGetDB( DB_MASTER ); - $rows = array(); - foreach ( $jobs as $job ) { - $rows[] = $job->insertFields(); - if ( count( $rows ) >= 500 ) { - $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' ); - $rows = array(); - } - } - if ( $rows ) { // last chunk - $dbw->insert( 'job', $rows, __METHOD__, 'IGNORE' ); - } - wfIncrStats( 'job-insert', count( $jobs ) ); - } - - /*------------------------------------------------------------------------- - * Non-static functions - *------------------------------------------------------------------------*/ - - function __construct( $command, $title, $params = false, $id = 0 ) { - $this->command = $command; - $this->title = $title; - $this->params = $params; - $this->id = $id; - - // A bit of premature generalisation - // Oh well, the whole class is premature generalisation really - $this->removeDuplicates = true; - } - - /** - * Insert a single job into the queue. - * @return bool true on success - */ - function insert() { - $fields = $this->insertFields(); - - $dbw = wfGetDB( DB_MASTER ); - - if ( $this->removeDuplicates ) { - $res = $dbw->select( 'job', array( '1' ), $fields, __METHOD__ ); - if ( $dbw->numRows( $res ) ) { - return; - } - } - return $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(), - 'job_params' => Job::makeBlob( $this->params ) - ); - } - - function toString() { - $paramString = ''; - if ( $this->params ) { - foreach ( $this->params as $key => $value ) { - if ( $paramString != '' ) { - $paramString .= ' '; - } - $paramString .= "$key=$value"; - } - } - - if ( is_object( $this->title ) ) { - $s = "{$this->command} " . $this->title->getPrefixedDBkey(); - if ( $paramString !== '' ) { - $s .= ' ' . $paramString; - } - return $s; - } else { - return "{$this->command} $paramString"; - } - } - - protected function setLastError( $error ) { - $this->error = $error; - } - - function getLastError() { - return $this->error; - } -}