Wikimedia\Rdbms\LoadMonitor Class Reference

Basic DB load monitor with no external dependencies Uses memcached to cache the replication lag for a short time. More...

Inheritance diagram for Wikimedia\Rdbms\LoadMonitor:

Collaboration diagram for Wikimedia\Rdbms\LoadMonitor:

Public Member Functions
	__construct (ILoadBalancer $lb, BagOStuff $srvCache, WANObjectCache $wCache, array $options=[])
	getLagTimes (array $serverIndexes, $domain)
	Get an estimate of replication lag (in seconds) for each server.
	scaleLoads (array &$weightByServer, $domain)
	Perform load ratio adjustment before deciding which server to use.
	setLogger (LoggerInterface $logger)

Protected Member Functions
	getServerStates (array $serverIndexes, $domain)
	getWeightScale ( $index, IDatabase $conn=null)

Protected Attributes
ILoadBalancer	$parent
LoggerInterface	$replLogger
BagOStuff	$srvCache
WANObjectCache	$wanCache

Private Member Functions
	getCacheKey (array $serverIndexes)

Private Attributes
int	$lagWarnThreshold
	Amount of replication lag in seconds before warnings are logged.
float	$movingAveRatio
	Moving average ratio (e.g.

Detailed Description

Basic DB load monitor with no external dependencies Uses memcached to cache the replication lag for a short time.

Definition at line 36 of file LoadMonitor.php.

Constructor & Destructor Documentation

__construct()

Wikimedia\Rdbms\LoadMonitor::__construct	(	ILoadBalancer	$lb,
		BagOStuff	$srvCache,
		WANObjectCache	$wCache,
		array	$options = []
	)

Parameters

ILoadBalancer	$lb
BagOStuff	$srvCache
WANObjectCache	$wCache
array	$options	movingAveRatio: moving average constant for server weight updates based on lag lagWarnThreshold: how many seconds of lag trigger warnings

Implements Wikimedia\Rdbms\ILoadMonitor.

Reimplemented in Wikimedia\Rdbms\LoadMonitorMySQL.

Definition at line 64 of file LoadMonitor.php.

References $options, and Wikimedia\Rdbms\LoadMonitor\$srvCache.

Member Function Documentation

getCacheKey()

Wikimedia\Rdbms\LoadMonitor::getCacheKey ( array  $serverIndexes )

private

Definition at line 236 of file LoadMonitor.php.

Referenced by Wikimedia\Rdbms\LoadMonitor\getServerStates().

getLagTimes()

Wikimedia\Rdbms\LoadMonitor::getLagTimes ( array  $serverIndexes,   $domain  )

final

Get an estimate of replication lag (in seconds) for each server.

Values may be "false" if replication is too broken to estimate

Parameters

int[]	$serverIndexes
string	$domain

Returns

array Map of (server index => float|int|bool)

Implements Wikimedia\Rdbms\ILoadMonitor.

Definition at line 94 of file LoadMonitor.php.

References Wikimedia\Rdbms\LoadMonitor\getServerStates().

getServerStates()

Wikimedia\Rdbms\LoadMonitor::getServerStates ( array  $serverIndexes,   $domain  )

protected

Definition at line 98 of file LoadMonitor.php.

References Wikimedia\Rdbms\LoadMonitor\$movingAveRatio, Wikimedia\Rdbms\LoadMonitor\$srvCache, $value, as, Wikimedia\Rdbms\LoadMonitor\getCacheKey(), Wikimedia\Rdbms\LoadMonitor\getWeightScale(), and use.

Referenced by Wikimedia\Rdbms\LoadMonitor\getLagTimes(), and Wikimedia\Rdbms\LoadMonitor\scaleLoads().

getWeightScale()

Wikimedia\Rdbms\LoadMonitor::getWeightScale (   $index, IDatabase  $conn = null  )

protected

Parameters

int	$index	Server index
IDatabase | null	$conn	Connection handle or null on connection failure

Returns

float

Reimplemented in Wikimedia\Rdbms\LoadMonitorMySQL.

Definition at line 232 of file LoadMonitor.php.

Referenced by Wikimedia\Rdbms\LoadMonitor\getServerStates().

scaleLoads()

Wikimedia\Rdbms\LoadMonitor::scaleLoads ( array &  $weightByServer,   $domain  )

final

Perform load ratio adjustment before deciding which server to use.

Parameters

int[]	&$weightByServer	Map of (server index => float weight)
string | bool	$domain

Implements Wikimedia\Rdbms\ILoadMonitor.

Definition at line 80 of file LoadMonitor.php.

References as, and Wikimedia\Rdbms\LoadMonitor\getServerStates().

setLogger()

Wikimedia\Rdbms\LoadMonitor::setLogger

(

LoggerInterface

$logger

)

Definition at line 76 of file LoadMonitor.php.

Member Data Documentation

$lagWarnThreshold

int Wikimedia\Rdbms\LoadMonitor::$lagWarnThreshold

private

Amount of replication lag in seconds before warnings are logged.

Definition at line 49 of file LoadMonitor.php.

$movingAveRatio

float Wikimedia\Rdbms\LoadMonitor::$movingAveRatio

private

Moving average ratio (e.g.

0.1 for 10% weight to new weight)

Definition at line 47 of file LoadMonitor.php.

Referenced by Wikimedia\Rdbms\LoadMonitor\getServerStates().

$parent

ILoadBalancer Wikimedia\Rdbms\LoadMonitor::$parent

protected

Definition at line 38 of file LoadMonitor.php.

$replLogger

LoggerInterface Wikimedia\Rdbms\LoadMonitor::$replLogger

protected

Definition at line 44 of file LoadMonitor.php.

$srvCache

BagOStuff Wikimedia\Rdbms\LoadMonitor::$srvCache

protected

Definition at line 40 of file LoadMonitor.php.

Referenced by Wikimedia\Rdbms\LoadMonitor\__construct(), Wikimedia\Rdbms\LoadMonitorMySQL\__construct(), and Wikimedia\Rdbms\LoadMonitor\getServerStates().

$wanCache

WANObjectCache Wikimedia\Rdbms\LoadMonitor::$wanCache

protected

Definition at line 42 of file LoadMonitor.php.

---

The documentation for this class was generated from the following file:

• includes/libs/rdbms/loadmonitor/LoadMonitor.php