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<?php
/**
* Database load monitoring.
*
* 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
* @ingroup Database
*/
/**
* An interface for database load monitoring
*
* @ingroup Database
*/
interface LoadMonitor {
/**
* Construct a new LoadMonitor with a given LoadBalancer parent
*
* @param LoadBalancer $parent
*/
public function __construct( $parent );
/**
* Perform pre-connection load ratio adjustment.
* @param array $loads
* @param string|bool $group The selected query group. Default: false
* @param string|bool $wiki Default: false
*/
public function scaleLoads( &$loads, $group = false, $wiki = false );
/**
* Return an estimate of replication lag for each server
*
* @param array $serverIndexes
* @param string $wiki
*
* @return array Map of (server index => seconds)
*/
public function getLagTimes( $serverIndexes, $wiki );
}
class LoadMonitorNull implements LoadMonitor {
public function __construct( $parent ) {
}
public function scaleLoads( &$loads, $group = false, $wiki = false ) {
}
public function getLagTimes( $serverIndexes, $wiki ) {
return array_fill_keys( $serverIndexes, 0 );
}
}
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