maintenance/nextJobDB.php

   1 <?php
   2 /**
   3  * Pick a database that has pending jobs
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Maintenance
  22  */
  23
  24 require_once( __DIR__ . '/Maintenance.php' );
  25
  26 /**
  27  * Maintenance script that picks a database that has pending jobs.
  28  *
  29  * @ingroup Maintenance
  30  */
  31 class nextJobDB extends Maintenance {
  32         public function __construct() {
  33                 parent::__construct();
  34                 $this->mDescription = "Pick a database that has pending jobs";
  35                 $this->addOption( 'type', "Search by job type", false, true );
  36                 $this->addOption( 'types', "Space separated list of job types to search for", false, true );
  37         }
  38
  39         public function execute() {
  40                 global $wgMemc;
  41
  42                 $type = false; // job type required/picked
  43                 if ( $this->hasOption( 'types' ) ) {
  44                         $types = explode( ' ', $this->getOption( 'types' ) );
  45                 } elseif ( $this->hasOption( 'type' ) ) {
  46                         $types = array( $this->getOption( 'type' ) );
  47                 } else {
  48                         $types = JobQueueGroup::singleton()->getDefaultQueueTypes();
  49                 }
  50
  51                 // Handle any required periodic queue maintenance
  52                 $this->executeReadyPeriodicTasks();
  53
  54                 // Get all the queues with jobs in them
  55                 $pendingDBs = JobQueueAggregator::singleton()->getAllReadyWikiQueues();
  56                 if ( !count( $pendingDBs ) ) {
  57                         return; // no DBs with jobs or cache is both empty and locked
  58                 }
  59
  60                 do {
  61                         $again = false;
  62
  63                         $candidates = array(); // list of (type, db)
  64                         // Flatten the tree of candidates into a flat list so that a random
  65                         // item can be selected, weighing each queue (type/db tuple) equally.
  66                         foreach ( $pendingDBs as $type => $dbs ) {
  67                                 if ( in_array( $type, $types ) ) {
  68                                         foreach ( $dbs as $db ) {
  69                                                 $candidates[] = array( $type, $db );
  70                                         }
  71                                 }
  72                         }
  73                         if ( !count( $candidates ) ) {
  74                                 return; // no jobs for this type
  75                         }
  76
  77                         list( $type, $db ) = $candidates[ mt_rand( 0, count( $candidates ) - 1 ) ];
  78                         if ( !$this->checkJob( $type, $db ) ) { // queue is actually empty?
  79                                 $pendingDBs[$type] = array_diff( $pendingDBs[$type], $db );
  80                                 JobQueueAggregator::singleton()->notifyQueueEmpty( $db, $type );
  81                                 $again = true;
  82                         }
  83                 } while ( $again );
  84
  85                 if ( $this->hasOption( 'types' ) ) {
  86                         $this->output( $db . " " . $type . "\n" );
  87                 } else {
  88                         $this->output( $db . "\n" );
  89                 }
  90         }
  91
  92         /**
  93          * Check if the specified database has a job of the specified type in it.
  94          * The type may be false to indicate "all".
  95          * @param $type string
  96          * @param $dbName string
  97          * @return bool
  98          */
  99         private function checkJob( $type, $dbName ) {
 100                 return !JobQueueGroup::singleton( $dbName )->get( $type )->isEmpty();
 101         }
 102
 103         /**
 104          * Do all ready periodic jobs for all databases every 5 minutes (and .1% of the time)
 105          * @return integer
 106          */
 107         private function executeReadyPeriodicTasks() {
 108                 global $wgLocalDatabases, $wgMemc;
 109
 110                 $count = 0;
 111                 $memcKey = 'jobqueue:periodic:lasttime';
 112                 $timestamp = (int)$wgMemc->get( $memcKey ); // UNIX timestamp or 0
 113                 if ( ( time() - $timestamp ) > 300 || mt_rand( 0, 999 ) == 0 ) { // 5 minutes
 114                         if ( $wgMemc->add( "$memcKey:rebuild", 1, 1800 ) ) { // lock
 115                                 foreach ( $wgLocalDatabases as $db ) {
 116                                         $count += JobQueueGroup::singleton( $db )->executeReadyPeriodicTasks();
 117                                 }
 118                                 $wgMemc->set( $memcKey, time() );
 119                                 $wgMemc->delete( "$memcKey:rebuild" ); // unlock
 120                         }
 121                 }
 122
 123                 return $count;
 124         }
 125 }
 126
 127 $maintClass = "nextJobDb";
 128 require_once( RUN_MAINTENANCE_IF_MAIN );