/**
* Pick a database that has pending jobs
*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
* @file
+ * @todo Make this work on PostgreSQL and maybe other database servers
* @ingroup Maintenance
*/
-$options = array( 'type' );
+require_once( __DIR__ . '/Maintenance.php' );
+
+/**
+ * Maintenance script that picks a database that has pending jobs.
+ *
+ * @ingroup Maintenance
+ */
+class nextJobDB extends Maintenance {
+ public function __construct() {
+ parent::__construct();
+ $this->mDescription = "Pick a database that has pending jobs";
+ $this->addOption( 'type', "The type of job to search for", false, true );
+ }
-require_once( 'commandLine.inc' );
+ public function execute() {
+ global $wgMemc;
+ $type = $this->getOption( 'type', false );
-$type = isset($options['type'])
- ? $options['type']
- : false;
+ $memcKey = 'jobqueue:dbs:v2';
+ $pendingDBs = $wgMemc->get( $memcKey );
-$mckey = $type === false
- ? "jobqueue:dbs"
- : "jobqueue:dbs:$type";
+ // If the cache entry wasn't present, or in 1% of cases otherwise,
+ // regenerate the cache.
+ if ( !$pendingDBs || mt_rand( 0, 100 ) == 0 ) {
+ $pendingDBs = $this->getPendingDbs();
+ $wgMemc->set( $memcKey, $pendingDBs, 300 );
+ }
-$pendingDBs = $wgMemc->get( $mckey );
-if ( !$pendingDBs ) {
- $pendingDBs = array();
- # Cross-reference DBs by master DB server
- $dbsByMaster = array();
- foreach ( $wgLocalDatabases as $db ) {
- $lb = wfGetLB( $db );
- $dbsByMaster[$lb->getServerName(0)][] = $db;
- }
+ if ( !$pendingDBs ) {
+ return;
+ }
- foreach ( $dbsByMaster as $master => $dbs ) {
- $dbConn = wfGetDB( DB_MASTER, array(), $dbs[0] );
- $stype = $dbConn->addQuotes($type);
+ do {
+ $again = false;
- # Padding row for MySQL bug
- $sql = "(SELECT '-------------------------------------------')";
- foreach ( $dbs as $dbName ) {
- if ( $sql != '' ) {
- $sql .= ' UNION ';
+ if ( $type === false ) {
+ $candidates = call_user_func_array( 'array_merge', $pendingDBs );
+ } elseif ( isset( $pendingDBs[$type] ) ) {
+ $candidates = $pendingDBs[$type];
+ } else {
+ $candidates = array();
}
- if ($type === false)
- $sql .= "(SELECT '$dbName' FROM `$dbName`.job LIMIT 1)";
- else
- $sql .= "(SELECT '$dbName' FROM `$dbName`.job WHERE job_cmd=$stype LIMIT 1)";
- }
- $res = $dbConn->query( $sql, 'nextJobDB.php' );
- $row = $dbConn->fetchRow( $res ); // discard padding row
- while ( $row = $dbConn->fetchRow( $res ) ) {
- $pendingDBs[] = $row[0];
+ if ( !$candidates ) {
+ return;
+ }
+
+ $candidates = array_values( $candidates );
+ $db = $candidates[ mt_rand( 0, count( $candidates ) - 1 ) ];
+ if ( !$this->checkJob( $type, $db ) ) {
+ // This job is not available in the current database. Remove it from
+ // the cache.
+ if ( $type === false ) {
+ foreach ( $pendingDBs as $type2 => $dbs ) {
+ $pendingDBs[$type2] = array_diff( $pendingDBs[$type2], array( $db ) );
+ }
+ } else {
+ $pendingDBs[$type] = array_diff( $pendingDBs[$type], array( $db ) );
+ }
+
+ $wgMemc->set( $memcKey, $pendingDBs, 300 );
+ $again = true;
+ }
+ } while ( $again );
+
+ $this->output( $db . "\n" );
+ }
+
+ /**
+ * Check if the specified database has a job of the specified type in it.
+ * The type may be false to indicate "all".
+ * @param $type string
+ * @param $dbName string
+ * @return bool
+ */
+ function checkJob( $type, $dbName ) {
+ $lb = wfGetLB( $dbName );
+ $db = $lb->getConnection( DB_MASTER, array(), $dbName );
+ if ( $type === false ) {
+ $conds = Job::defaultQueueConditions( );
+ } else {
+ $conds = array( 'job_cmd' => $type );
}
+
+
+ $exists = (bool) $db->selectField( 'job', '1', $conds, __METHOD__ );
+ $lb->reuseConnection( $db );
+ return $exists;
}
- $wgMemc->set( $mckey, $pendingDBs, 300 );
-}
+ /**
+ * Get all databases that have a pending job
+ * @return array
+ */
+ private function getPendingDbs() {
+ global $wgLocalDatabases;
+ $pendingDBs = array();
+ # Cross-reference DBs by master DB server
+ $dbsByMaster = array();
+ foreach ( $wgLocalDatabases as $db ) {
+ $lb = wfGetLB( $db );
+ $dbsByMaster[$lb->getServerName( 0 )][] = $db;
+ }
-if ( $pendingDBs ) {
- echo $pendingDBs[mt_rand(0, count( $pendingDBs ) - 1)];
-}
+ foreach ( $dbsByMaster as $dbs ) {
+ $dbConn = wfGetDB( DB_MASTER, array(), $dbs[0] );
+
+ # Padding row for MySQL bug
+ $pad = str_repeat( '-', 40 );
+ $sql = "(SELECT '$pad' as db, '$pad' as job_cmd)";
+ foreach ( $dbs as $wikiId ) {
+ if ( $sql != '' ) {
+ $sql .= ' UNION ';
+ }
+ list( $dbName, $tablePrefix ) = wfSplitWikiID( $wikiId );
+ $dbConn->tablePrefix( $tablePrefix );
+ $jobTable = $dbConn->tableName( 'job' );
+
+ $sql .= "(SELECT DISTINCT '$wikiId' as db, job_cmd FROM $dbName.$jobTable GROUP BY job_cmd)";
+ }
+ $res = $dbConn->query( $sql, __METHOD__ );
+ $first = true;
+ foreach ( $res as $row ) {
+ if ( $first ) {
+ // discard padding row
+ $first = false;
+ continue;
+ }
+ $pendingDBs[$row->job_cmd][] = $row->db;
+ }
+ }
+ return $pendingDBs;
+ }
+}
+$maintClass = "nextJobDb";
+require_once( RUN_MAINTENANCE_IF_MAIN );