An interface for generating database load balancers. More...

Inheritance diagram for LBFactory:

Collaboration diagram for LBFactory:

Public Member Functions
	__construct (array $conf)
	Construct a factory based on a configuration array (typically from $wgLBFactoryConf) More...

	closeAll ()
	Close all open database connections on all open load balancers. More...

	commitAll ($fname=__METHOD__, array $options=[])
	Commit on all connections. More...

	commitMasterChanges ($fname=__METHOD__, array $options=[])
	Commit changes on all master connections. More...

	destroy ()
	Disables all load balancers. More...

	disableChronologyProtection ()
	Disable the ChronologyProtector for all load balancers. More...

	forEachLB ($callback, array $params=[])
	Execute a function for each tracked load balancer The callback is called with the load balancer as the first parameter, and $params passed as the subsequent parameters. More...

&	getExternalLB ($cluster, $wiki=false)
	Get a cached (tracked) load balancer for external storage. More...

	getMainLB ($wiki=false)
	Get a cached (tracked) load balancer object. More...

	hasMasterChanges ()
	Determine if any master connection has pending changes. More...

	hasOrMadeRecentMasterChanges ()
	Determine if any master connection has pending/written changes from this request. More...

	laggedSlaveUsed ()
	Detemine if any lagged slave connection was used. More...

	newMainLB ($wiki=false)
	Create a new load balancer object. More...

	rollbackMasterChanges ($fname=__METHOD__)
	Rollback changes on all master connections. More...

	shutdown ($flags=0)
	Prepare all tracked load balancers for shutdown. More...

	waitForReplication (array $opts=[])
	Waits for the slave DBs to catch up to the current master position. More...

Static Public Member Functions
static	destroyInstance ()
	Shut down, close connections and destroy the cached instance. More...

static	disableBackend ()
	Disables all access to the load balancer, will cause all database access to throw a DBAccessError. More...

static	getLBFactoryClass (array $config)
	Returns the LBFactory class to use and the load balancer configuration. More...

static	singleton ()
	Get an LBFactory instance. More...

Public Attributes
const	SHUTDOWN_NO_CHRONPROT = 1

Protected Member Functions
	newChronologyProtector ()

	newExternalLB ($cluster, $wiki=false)
	Create a new load balancer for external storage. More...

	shutdownChronologyProtector (ChronologyProtector $cp)

Protected Attributes
ChronologyProtector	$chronProt

LoggerInterface	$logger

string bool	$readOnlyReason = false
	Reason all LBs are read-only or false if not. More...

TransactionProfiler	$trxProfiler

Private Member Functions
	forEachLBCallMethod ($methodName, array $args=[])
	Call a method of each tracked load balancer. More...

	logIfMultiDbTransaction ()
	Log query info if multi DB transactions are going to be committed now. More...

Detailed Description

An interface for generating database load balancers.

Definition at line 33 of file LBFactory.php.

Constructor & Destructor Documentation

LBFactory::__construct ( array $conf )

Construct a factory based on a configuration array (typically from $wgLBFactoryConf)

Parameters

array $conf

Definition at line 53 of file LBFactory.php.

References Profiler\instance(), and newChronologyProtector().

Member Function Documentation

LBFactory::closeAll ( )

Close all open database connections on all open load balancers.

Since: 1.28

Definition at line 453 of file LBFactory.php.

References forEachLBCallMethod().

LBFactory::commitAll	(		$fname = `__METHOD__`,
		array	$options = `[]`
	)

Commit on all connections.

Done for two reasons:

To commit changes to the masters.
To release the snapshot on all connections, master and slave.
Parameters
string $fname Caller name

array $options Options map:

maxWriteDuration: abort if more than this much time was spent in write queries

Definition at line 210 of file LBFactory.php.

References $fname, $options, commitMasterChanges(), and forEachLBCallMethod().

LBFactory::commitMasterChanges	(		$fname = `__METHOD__`,
		array	$options = `[]`
	)

Commit changes on all master connections.

Parameters

string	$fname	Caller name
array	$options	Options map: maxWriteDuration: abort if more than this much time was spent in write queries

Definition at line 221 of file LBFactory.php.

References $fname, $options, forEachLBCallMethod(), and logIfMultiDbTransaction().

Referenced by commitAll(), LBFactorySimple\shutdown(), and LBFactoryMulti\shutdown().

LBFactory::destroy ( )

Disables all load balancers.

All connections are closed, and any attempt to open a new connection will result in a DBAccessError.

See Also: LoadBalancer::disable()

Implements MediaWiki\Services\DestructibleService.

Definition at line 68 of file LBFactory.php.

References forEachLBCallMethod(), and shutdown().

static LBFactory::destroyInstance ( )

static

Shut down, close connections and destroy the cached instance.

Deprecated:: since 1.27, use LBFactory::destroy()

Definition at line 128 of file LBFactory.php.

Referenced by Maintenance\finalSetup().

static LBFactory::disableBackend ( )

static

Disables all access to the load balancer, will cause all database access to throw a DBAccessError.

Definition at line 77 of file LBFactory.php.

LBFactory::disableChronologyProtection ( )

Disable the ChronologyProtector for all load balancers.

This can be called at the start of special API entry points

Since: 1.27

Definition at line 400 of file LBFactory.php.

LBFactory::forEachLB	(		$callback,
		array	$params = `[]`
	)

abstract

Execute a function for each tracked load balancer The callback is called with the load balancer as the first parameter, and $params passed as the subsequent parameters.

Parameters

callable	$callback
array	$params

Referenced by forEachLBCallMethod(), hasMasterChanges(), hasOrMadeRecentMasterChanges(), laggedSlaveUsed(), logIfMultiDbTransaction(), shutdownChronologyProtector(), and waitForReplication().

LBFactory::forEachLBCallMethod	(		$methodName,
		array	$args = `[]`
	)

private

Call a method of each tracked load balancer.

Parameters

string	$methodName
array	$args

Definition at line 193 of file LBFactory.php.

References $args, array(), and forEachLB().

Referenced by closeAll(), commitAll(), commitMasterChanges(), destroy(), and rollbackMasterChanges().

& LBFactory::getExternalLB	(	$cluster,
		$wiki = `false`
	)

abstract

Get a cached (tracked) load balancer for external storage.

Parameters

string	$cluster	External storage cluster, or false for core
bool \| string	$wiki	Wiki ID, or false for the current wiki

Returns: LoadBalancer

Referenced by waitForReplication().

static LBFactory::getLBFactoryClass ( array $config )

static

Returns the LBFactory class to use and the load balancer configuration.

Todo:: instead of this, use a ServiceContainer for managing the different implementations.

Parameters

array $config (e.g. $wgLBFactoryConf)

Returns: string Class name

Definition at line 100 of file LBFactory.php.

References wfDeprecated().

Referenced by LBFactoryTest\testGetLBFactoryClass().

LBFactory::getMainLB ( $wiki = false )

abstract

Get a cached (tracked) load balancer object.

Parameters

bool | string $wiki Wiki ID, or false for the current wiki

Returns: LoadBalancer

Referenced by waitForReplication().

LBFactory::hasMasterChanges ( )

Determine if any master connection has pending changes.

Returns: bool

Since: 1.23

Definition at line 273 of file LBFactory.php.

References $ret, forEachLB(), LoadBalancer\hasMasterChanges(), and use.

LBFactory::hasOrMadeRecentMasterChanges ( )

Determine if any master connection has pending/written changes from this request.

Returns: bool

Since: 1.27

Definition at line 301 of file LBFactory.php.

References $ret, forEachLB(), LoadBalancer\hasOrMadeRecentMasterChanges(), and use.

LBFactory::laggedSlaveUsed ( )

Detemine if any lagged slave connection was used.

Since: 1.27

Returns: bool

Definition at line 287 of file LBFactory.php.

References $ret, forEachLB(), LoadBalancer\laggedSlaveUsed(), and use.

LBFactory::logIfMultiDbTransaction ( )

private

Log query info if multi DB transactions are going to be committed now.

Definition at line 248 of file LBFactory.php.

References as, forEachLB(), LoadBalancer\getServerName(), LoadBalancer\getWriterIndex(), LoadBalancer\pendingMasterChangeCallers(), and use.

Referenced by commitMasterChanges().

LBFactory::newChronologyProtector ( )

protected

Returns: ChronologyProtector

Definition at line 407 of file LBFactory.php.

References $chronProt, $request, RequestContext\getMain(), ObjectCache\getMainStashInstance(), ChronologyProtector\setEnabled(), and ChronologyProtector\setWaitEnabled().

Referenced by __construct().

LBFactory::newExternalLB	(	$cluster,
		$wiki = `false`
	)

abstractprotected

Create a new load balancer for external storage.

The resulting object will be untracked, not chronology-protected, and the caller is responsible for cleaning it up.

Parameters

string	$cluster	External storage cluster, or false for core
bool \| string	$wiki	Wiki ID, or false for the current wiki

Returns: LoadBalancer

LBFactory::newMainLB ( $wiki = false )

abstract

Create a new load balancer object.

The resulting object will be untracked, not chronology-protected, and the caller is responsible for cleaning it up.

Parameters

bool | string $wiki Wiki ID, or false for the current wiki

Returns: LoadBalancer

LBFactory::rollbackMasterChanges ( $fname = __METHOD__ )

Rollback changes on all master connections.

Parameters

string $fname Caller name

Since: 1.23

Definition at line 241 of file LBFactory.php.

References $fname, and forEachLBCallMethod().

LBFactory::shutdown ( $flags = 0 )

Prepare all tracked load balancers for shutdown.

Parameters

integer $flags Supports SHUTDOWN_* flags STUB

Definition at line 184 of file LBFactory.php.

Referenced by destroy().

LBFactory::shutdownChronologyProtector ( ChronologyProtector $cp )

protected

Parameters

ChronologyProtector $cp

Definition at line 430 of file LBFactory.php.

References forEachLB(), LoadBalancer\getServerName(), LoadBalancer\getWriterIndex(), ChronologyProtector\shutdown(), ChronologyProtector\shutdownLB(), use, and LoadBalancer\waitForAll().

Referenced by LBFactorySimple\shutdown(), and LBFactoryMulti\shutdown().

static LBFactory::singleton ( )

static

Get an LBFactory instance.

Deprecated:: since 1.27, use MediaWikiServices::getDBLoadBalancerFactory() instead.

Returns: LBFactory

Definition at line 88 of file LBFactory.php.

LBFactory::waitForReplication ( array $opts = [] )

Waits for the slave DBs to catch up to the current master position.

Use this when updating very large numbers of rows, as in maintenance scripts, to avoid causing too much lag. Of course, this is a no-op if there are no slaves.

By default this waits on all DB clusters actually used in this request. This makes sense when lag being waiting on is caused by the code that does this check. In that case, setting "ifWritesSince" can avoid the overhead of waiting for clusters that were not changed since the last wait check. To forcefully wait on a specific cluster for a given wiki, use the 'wiki' parameter. To forcefully wait on an "external" cluster, use the "cluster" parameter.

Never call this function after a large DB write that is still in a transaction. It only makes sense to call this after the possible lag inducing changes were committed.

Parameters

array

$opts

Optional fields that include:

wiki : wait on the load balancer DBs that handles the given wiki
cluster : wait on the given external load balancer DBs
timeout : Max wait time. Default: ~60 seconds
ifWritesSince: Only wait if writes were done since this UNIX timestamp

Exceptions

DBReplicationWaitError If a timeout or error occured waiting on a DB cluster

Since: 1.27

Definition at line 333 of file LBFactory.php.

References as, forEachLB(), getExternalLB(), getMainLB(), and use.

Member Data Documentation

ChronologyProtector LBFactory::$chronProt

protected

Definition at line 36 of file LBFactory.php.

Referenced by newChronologyProtector().

LoggerInterface LBFactory::$logger

protected

Definition at line 42 of file LBFactory.php.

string bool LBFactory::$readOnlyReason = false

protected

Reason all LBs are read-only or false if not.

Definition at line 45 of file LBFactory.php.

Referenced by LBFactoryMulti\newLoadBalancer(), and LBFactoryMulti\newMainLB().

TransactionProfiler LBFactory::$trxProfiler

protected

Definition at line 39 of file LBFactory.php.

const LBFactory::SHUTDOWN_NO_CHRONPROT = 1

Definition at line 47 of file LBFactory.php.

Referenced by MediaWiki\restInPeace().

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

includes/db/loadbalancer/LBFactory.php

Public Member Functions

Static Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Private Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation