includes/libs/rdbms/loadmonitor/ILoadMonitor.php

   1 <?php
   2 /**
   3  * Database load monitoring interface
   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 Database
  22  */
  23
  24 namespace Wikimedia\Rdbms;
  25
  26 use Psr\Log\LoggerAwareInterface;
  27 use BagOStuff;
  28 use WANObjectCache;
  29
  30 /**
  31  * An interface for database load monitoring
  32  *
  33  * @ingroup Database
  34  */
  35 interface ILoadMonitor extends LoggerAwareInterface {
  36         /**
  37          * Construct a new LoadMonitor with a given LoadBalancer parent
  38          *
  39          * @param ILoadBalancer $lb LoadBalancer this instance serves
  40          * @param BagOStuff $sCache Local server memory cache
  41          * @param WANObjectCache $wCache Local cluster memory cache
  42          * @param array $options Options map
  43          */
  44         public function __construct(
  45                 ILoadBalancer $lb, BagOStuff $sCache, WANObjectCache $wCache, array $options = []
  46         );
  47
  48         /**
  49          * Perform load ratio adjustment before deciding which server to use
  50          *
  51          * @param int[] &$weightByServer Map of (server index => float weight)
  52          * @param string|bool $domain
  53          */
  54         public function scaleLoads( array &$weightByServer, $domain );
  55
  56         /**
  57          * Get an estimate of replication lag (in seconds) for each server
  58          *
  59          * Values may be "false" if replication is too broken to estimate
  60          *
  61          * @param int[] $serverIndexes
  62          * @param string $domain
  63          * @return array Map of (server index => float|int|bool)
  64          */
  65         public function getLagTimes( array $serverIndexes, $domain );
  66 }