3 * Pick a database that has pending jobs
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.
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.
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
21 * @ingroup Maintenance
24 require_once( __DIR__
. '/Maintenance.php' );
27 * Maintenance script that picks a database that has pending jobs.
29 * @ingroup Maintenance
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 );
39 public function execute() {
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' ) );
51 $memcKey = 'jobqueue:dbs:v3';
52 $pendingDbInfo = $wgMemc->get( $memcKey );
54 // If the cache entry wasn't present, is stale, or in .1% of cases otherwise,
55 // regenerate the cache. Use any available stale cache if another process is
56 // currently regenerating the pending DB information.
57 if ( !is_array( $pendingDbInfo )
58 ||
( time() - $pendingDbInfo['timestamp'] ) > 300 // 5 minutes
59 ||
mt_rand( 0, 999 ) == 0
61 if ( $wgMemc->add( "$memcKey:rebuild", 1, 1800 ) ) { // lock
62 $pendingDbInfo = array(
63 'pendingDBs' => $this->getPendingDbs(),
66 for ( $attempts=1; $attempts <= 25; ++
$attempts ) {
67 if ( $wgMemc->add( "$memcKey:lock", 1, 60 ) ) { // lock
68 $wgMemc->set( $memcKey, $pendingDbInfo );
69 $wgMemc->delete( "$memcKey:lock" ); // unlock
73 $wgMemc->delete( "$memcKey:rebuild" ); // unlock
77 if ( !is_array( $pendingDbInfo ) ||
!$pendingDbInfo['pendingDBs'] ) {
78 return; // no DBs with jobs or cache is both empty and locked
81 $pendingDBs = $pendingDbInfo['pendingDBs']; // convenience
85 if ( $types === false ) {
86 $candidates = call_user_func_array( 'array_merge', $pendingDBs );
88 $candidates = array();
89 $possTypes = array_intersect( $types, array_keys( $pendingDBs ) );
91 $possTypes = array_values( $possTypes );
92 $type = $possTypes[ mt_rand( 0, count( $possTypes ) - 1 ) ];
93 $candidates = $pendingDBs[$type];
97 return; // no jobs for this type
100 $candidates = array_values( $candidates );
101 $db = $candidates[ mt_rand( 0, count( $candidates ) - 1 ) ];
102 if ( !$this->checkJob( $type, $db ) ) {
103 $pendingDBs = $this->delistDB( $pendingDBs, $db, $type );
104 // Update the cache to remove the outdated information.
105 // Make sure that this does not race (especially with full rebuilds).
106 if ( $wgMemc->add( "$memcKey:lock", 1, 60 ) ) { // lock
107 $curInfo = $wgMemc->get( $memcKey );
108 if ( is_array( $curInfo ) ) {
109 $curInfo['pendingDBs'] =
110 $this->delistDB( $curInfo['pendingDBs'], $db, $type );
111 $wgMemc->set( $memcKey, $curInfo );
112 // May as well make use of this newer information
113 $pendingDBs = $curInfo['pendingDBs'];
115 $wgMemc->delete( "$memcKey:lock" ); // unlock
121 if ( $this->hasOption( 'types' ) ) {
122 $this->output( $db . " " . $type . "\n" );
124 $this->output( $db . "\n" );
128 private function delistDB( array $pendingDBs, $db, $type ) {
129 if ( $type === false ) {
130 // There are no jobs available in the current database
131 foreach ( $pendingDBs as $type2 => $dbs ) {
132 $pendingDBs[$type2] = array_diff( $pendingDBs[$type2], array( $db ) );
135 // There are no jobs of this type available in the current database
136 $pendingDBs[$type] = array_diff( $pendingDBs[$type], array( $db ) );
142 * Check if the specified database has a job of the specified type in it.
143 * The type may be false to indicate "all".
144 * @param $type string
145 * @param $dbName string
148 private function checkJob( $type, $dbName ) {
149 $group = JobQueueGroup
::singleton( $dbName );
150 if ( $type === false ) {
151 foreach ( $group->getDefaultQueueTypes() as $type ) {
152 if ( !$group->get( $type )->isEmpty() ) {
158 return !$group->get( $type )->isEmpty();
163 * Get all databases that have a pending job
166 private function getPendingDbs() {
167 global $wgLocalDatabases;
169 $pendingDBs = array(); // (job type => (db list))
170 foreach ( $wgLocalDatabases as $db ) {
171 $types = JobQueueGroup
::singleton( $db )->getQueuesWithJobs();
172 foreach ( $types as $type ) {
173 $pendingDBs[$type][] = $db;
181 $maintClass = "nextJobDb";
182 require_once( RUN_MAINTENANCE_IF_MAIN
);