3 * Database load monitoring.
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
25 * An interface for database load monitoring
29 interface LoadMonitor
{
31 * Construct a new LoadMonitor with a given LoadBalancer parent
33 * @param LoadBalancer $parent
35 public function __construct( $parent );
38 * Perform pre-connection load ratio adjustment.
40 * @param string|bool $group The selected query group. Default: false
41 * @param string|bool $wiki Default: false
43 public function scaleLoads( &$loads, $group = false, $wiki = false );
46 * Return an estimate of replication lag for each server
48 * @param array $serverIndexes
51 * @return array Map of (server index => seconds)
53 public function getLagTimes( $serverIndexes, $wiki );
56 class LoadMonitorNull
implements LoadMonitor
{
57 public function __construct( $parent ) {
60 public function scaleLoads( &$loads, $group = false, $wiki = false ) {
63 public function getLagTimes( $serverIndexes, $wiki ) {
64 return array_fill_keys( $serverIndexes, 0 );