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 LoadMonitor:

Collaboration diagram for LoadMonitor:

Public Member Functions
	__construct (ILoadBalancer $lb, BagOStuff $srvCache, BagOStuff $cache, array $options=[])
	Construct a new LoadMonitor with a given LoadBalancer parent. More...
	getLagTimes (array $serverIndexes, $domain)
	Get an estimate of replication lag (in seconds) for each server. More...
	scaleLoads (array &$weightByServer, $domain)
	Perform load ratio adjustment before deciding which server to use. More...
	setLogger (LoggerInterface $logger)

Public Attributes
const	VERSION = 1

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

Protected Attributes
BagOStuff	$mainCache
ILoadBalancer	$parent
LoggerInterface	$replLogger
BagOStuff	$srvCache

Private Member Functions
	getCacheKey (array $serverIndexes)

Private Attributes
float	$movingAveRatio
	Moving average ratio (e.g. More...

Detailed Description

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

Definition at line 31 of file LoadMonitor.php.

Constructor & Destructor Documentation

LoadMonitor::__construct	(	ILoadBalancer	$lb,
		BagOStuff	$sCache,
		BagOStuff	$cCache,
		array	$options = []
	)

Construct a new LoadMonitor with a given LoadBalancer parent.

Parameters

ILoadBalancer	$lb	LoadBalancer this instance serves
BagOStuff	$sCache	Local server memory cache
BagOStuff	$cCache	Local cluster memory cache
array	$options	Options map

Implements ILoadMonitor.

Definition at line 46 of file LoadMonitor.php.

References $cache, $options, and $srvCache.

Member Function Documentation

LoadMonitor::getCacheKey ( array  $serverIndexes )

private

Definition at line 205 of file LoadMonitor.php.

Referenced by getServerStates().

LoadMonitor::getLagTimes	(	array	$serverIndexes,
			$domain
	)

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

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

Parameters

	integer[]	$serverIndexes
string	$domain

Returns

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

Implements ILoadMonitor.

Definition at line 77 of file LoadMonitor.php.

References getServerStates().

LoadMonitor::getServerStates ( array  $serverIndexes,   $domain  )

protected

Definition at line 83 of file LoadMonitor.php.

References $cache, $mainCache, $movingAveRatio, $value, as, getCacheKey(), getWeightScale(), and use.

Referenced by getLagTimes(), and scaleLoads().

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

protected

Parameters

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

Returns

float

Definition at line 201 of file LoadMonitor.php.

Referenced by getServerStates().

LoadMonitor::scaleLoads	(	array &	$weightByServer,
			$domain
	)

Perform load ratio adjustment before deciding which server to use.

Parameters

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

Implements ILoadMonitor.

Definition at line 63 of file LoadMonitor.php.

References as, and getServerStates().

LoadMonitor::setLogger

(

LoggerInterface

$logger

)

Definition at line 59 of file LoadMonitor.php.

Member Data Documentation

BagOStuff LoadMonitor::$mainCache

protected

Definition at line 37 of file LoadMonitor.php.

Referenced by getServerStates().

float LoadMonitor::$movingAveRatio

private

Moving average ratio (e.g.

0.1 for 10% weight to new weight)

Definition at line 42 of file LoadMonitor.php.

Referenced by getServerStates().

ILoadBalancer LoadMonitor::$parent

protected

Definition at line 33 of file LoadMonitor.php.

LoggerInterface LoadMonitor::$replLogger

protected

Definition at line 39 of file LoadMonitor.php.

BagOStuff LoadMonitor::$srvCache

protected

Definition at line 35 of file LoadMonitor.php.

Referenced by __construct().

const LoadMonitor::VERSION = 1

Definition at line 44 of file LoadMonitor.php.

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

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