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  * @todo Make this work on PostgreSQL and maybe other database servers
  21  * @ingroup Maintenance
  22  */
  23
  24 require_once( dirname( __FILE__ ) . '/Maintenance.php' );
  25
  26 class nextJobDB extends Maintenance {
  27         public function __construct() {
  28                 parent::__construct();
  29                 $this->mDescription = "Pick a database that has pending jobs";
  30                 $this->addOption( 'type', "The type of job to search for", false, true );
  31         }
  32
  33         public function execute() {
  34                 global $wgMemc;
  35                 $type = $this->getOption( 'type', false );
  36                 $mckey = $type === false
  37                                         ? "jobqueue:dbs"
  38                                         : "jobqueue:dbs:$type";
  39                 $pendingDBs = $wgMemc->get( $mckey );
  40
  41                 # If we didn't get it from the cache
  42                 if ( !$pendingDBs ) {
  43                         $pendingDBs = $this->getPendingDbs( $type );
  44                         $wgMemc->get( $mckey, $pendingDBs, 300 );
  45                 }
  46                 # If we've got a pending job in a db, display it.
  47                 if ( $pendingDBs ) {
  48                         $this->output( $pendingDBs[mt_rand( 0, count( $pendingDBs ) - 1 )] );
  49                 }
  50         }
  51
  52         /**
  53          * Get all databases that have a pending job
  54          * @param $type String Job type
  55          * @return array
  56          */
  57         private function getPendingDbs( $type ) {
  58                 global $wgLocalDatabases;
  59                 $pendingDBs = array();
  60                 # Cross-reference DBs by master DB server
  61                 $dbsByMaster = array();
  62                 foreach ( $wgLocalDatabases as $db ) {
  63                         $lb = wfGetLB( $db );
  64                         $dbsByMaster[$lb->getServerName( 0 )][] = $db;
  65                 }
  66
  67                 foreach ( $dbsByMaster as $master => $dbs ) {
  68                         $dbConn = wfGetDB( DB_MASTER, array(), $dbs[0] );
  69                         $stype = $dbConn->addQuotes( $type );
  70
  71                         # Padding row for MySQL bug
  72                         $sql = "(SELECT '-------------------------------------------' as db)";
  73                         foreach ( $dbs as $wikiId ) {
  74                                 if ( $sql != '' ) {
  75                                         $sql .= ' UNION ';
  76                                 }
  77
  78                                 list( $dbName, $tablePrefix ) = wfSplitWikiID( $wikiId );
  79                                 $dbConn->tablePrefix( $tablePrefix );
  80                                 $jobTable = $dbConn->tableName( 'job' );
  81
  82                                 if ( $type === false )
  83                                         $sql .= "(SELECT '$wikiId' as db FROM $dbName.$jobTable LIMIT 1)";
  84                                 else
  85                                         $sql .= "(SELECT '$wikiId' as db FROM $dbName.$jobTable WHERE job_cmd=$stype LIMIT 1)";
  86                         }
  87                         $res = $dbConn->query( $sql, __METHOD__ );
  88                         $first = true;
  89                         foreach ( $res as $row ) {
  90                                 if ( $first ) {
  91                                         // discard padding row
  92                                         $first = false;
  93                                         continue;
  94                                 }
  95                                 $pendingDBs[] = $row->db;
  96                         }
  97                 }
  98                 return $pendingDBs;
  99         }
 100 }
 101
 102 $maintClass = "nextJobDb";
 103 require_once( DO_MAINTENANCE );