Class for managing the deferred updates. More...

Collaboration diagram for DeferredUpdates:

Static Public Member Functions
static	addCallableUpdate ( $callable, $stage=self::POSTSEND, $dbw=null)
	Add a callable update.

static	addUpdate (DeferrableUpdate $update, $stage=self::POSTSEND)
	Add an update to the deferred list to be run later by execute()

static	clearPendingUpdates ()
	Clear all pending updates without performing them.

static	doUpdates ( $mode='run', $stage=self::ALL)
	Do any deferred updates and clear the list.

static	getPendingUpdates ( $stage=self::ALL)

static	pendingUpdatesCount ()

static	tryOpportunisticExecute ( $mode='run')
	Run all deferred updates immediately if there are no DB writes active.

Public Attributes
const	ALL = 0

const	BIG_QUEUE_SIZE = 100

const	POSTSEND = 2

const	PRESEND = 1

Static Protected Member Functions
static	execute (array &$queue, $mode, $stage)
	Immediately run/queue a list of updates.

Static Private Member Functions
static	areDatabaseTransactionsActive ()

static	enqueueUpdates (array $updates)
	Enqueue a job for each EnqueueableDataUpdate item and return the other items.

static	push (array &$queue, DeferrableUpdate $update)

static	runUpdate (DeferrableUpdate $update, LBFactory $lbFactory, $mode, $stage)

Static Private Attributes
static array null	$executeContext
	Information about the current execute() call or null if not running.

static DeferrableUpdate[]	$postSendUpdates = []
	Updates to be deferred until after request end.

static DeferrableUpdate[]	$preSendUpdates = []
	Updates to be deferred until before request end.

Detailed Description

Class for managing the deferred updates.

In web request mode, deferred updates can be run at the end of the request, either before or after the HTTP response has been sent. In either case, they run after the DB commit step. If an update runs after the response is sent, it will not block clients. If sent before, it will run synchronously. These two modes are defined via PRESEND and POSTSEND constants, the latter being the default for addUpdate() and addCallableUpdate().

Updates that work through this system will be more likely to complete by the time the client makes their next request after this one than with the JobQueue system.

In CLI mode, deferred updates will run:

a) During DeferredUpdates::addUpdate if no LBFactory DB handles have writes pending
b) On commit of an LBFactory DB handle if no other such handles have writes pending
c) During an LBFactory::waitForReplication call if no LBFactory DBs have writes pending
d) When the queue is large and an LBFactory DB handle commits (EnqueueableDataUpdate only)
e) At the completion of Maintenance::execute()

See also: Maintenance::setLBFactoryTriggers

When updates are deferred, they go into one two FIFO "top-queues" (one for pre-send and one for post-send). Updates enqueued during doUpdate() of a "top" update go into the "sub-queue" for that update. After that method finishes, the sub-queue is run until drained. This continues for each top-queue job until the entire top queue is drained. This happens for the pre-send top-queue, and later on, the post-send top-queue, in execute().

Since: 1.19

Definition at line 56 of file DeferredUpdates.php.

Member Function Documentation

◆ addCallableUpdate()

static DeferredUpdates::addCallableUpdate	(	$callable,
		$stage = self::POSTSEND,
		$dbw = null )

static

Add a callable update.

In a lot of cases, we just need a callback/closure, defining a new DeferrableUpdate object is not necessary

See also: MWCallableUpdate::__construct()

Parameters

callable	$callable
int	$stage	DeferredUpdates constant (PRESEND or POSTSEND) (since 1.27)
IDatabase \| IDatabase[] \| null	$dbw	Abort if this DB is rolled back [optional] (since 1.28)

Definition at line 118 of file DeferredUpdates.php.

References wfGetCaller().

Referenced by MediaWiki\Logger\Monolog\BufferHandler\handle().

◆ addUpdate()

static DeferredUpdates::addUpdate	(	DeferrableUpdate	$update,
			$stage = self::POSTSEND )

static

Add an update to the deferred list to be run later by execute()

In CLI mode, callback magic will also be used to run updates when safe

Parameters

DeferrableUpdate	$update	Some object that implements doUpdate()
int	$stage	DeferredUpdates constant (PRESEND or POSTSEND) (since 1.27)

Definition at line 79 of file DeferredUpdates.php.

References $wgCommandLineMode, and and().

◆ areDatabaseTransactionsActive()

static DeferredUpdates::areDatabaseTransactionsActive ( )

staticprivate

Returns: bool If a transaction round is active or connection is not ready for commit()

Definition at line 385 of file DeferredUpdates.php.

References and(), Wikimedia\Rdbms\IDatabase\explicitTrxActive(), Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), and Wikimedia\Rdbms\IDatabase\writesOrCallbacksPending().

◆ clearPendingUpdates()

static DeferredUpdates::clearPendingUpdates ( )

static

Clear all pending updates without performing them.

Generally, you don't want or need to call this. Unit tests need it though.

Definition at line 377 of file DeferredUpdates.php.

◆ doUpdates()

static DeferredUpdates::doUpdates	(		$mode = 'run',
			$stage = self::ALL )

static

Do any deferred updates and clear the list.

If $stage is self::ALL then the queue of PRESEND updates will be resolved, followed by the queue of POSTSEND updates

Parameters

string	$mode	Use "enqueue" to use the job queue when possible [Default: "run"]
int	$stage	DeferredUpdates constant (PRESEND, POSTSEND, or ALL) (since 1.27)

Definition at line 133 of file DeferredUpdates.php.

References execute().

◆ enqueueUpdates()

static DeferredUpdates::enqueueUpdates ( array $updates )

staticprivate

Enqueue a job for each EnqueueableDataUpdate item and return the other items.

Parameters

DeferrableUpdate[] $updates A list of deferred update instances

Returns: DeferrableUpdate[] Remaining updates that do not support being queued

Definition at line 333 of file DeferredUpdates.php.

References and().

◆ execute()

static DeferredUpdates::execute	(	array &	$queue,
			$mode,
			$stage )

staticprotected

Immediately run/queue a list of updates.

Parameters

DeferrableUpdate[]	&$queue	List of DeferrableUpdate objects
string	$mode	Use "enqueue" to use the job queue when possible
int	$stage	Class constant (PRESEND, POSTSEND) (since 1.28)

Exceptions

ErrorPageError	Happens on top-level calls
Exception	Happens on second-level calls

Definition at line 180 of file DeferredUpdates.php.

References $queue, $services, and(), and key.

◆ getPendingUpdates()

static DeferredUpdates::getPendingUpdates ( $stage = self::ALL )

static

Parameters

int $stage DeferredUpdates constant (PRESEND, POSTSEND, or ALL)

Returns: DeferrableUpdate[]

Since: 1.29

Definition at line 362 of file DeferredUpdates.php.

References and().

◆ pendingUpdatesCount()

static DeferredUpdates::pendingUpdatesCount ( )

static

Returns: int Number of enqueued updates

Since: 1.28

Definition at line 353 of file DeferredUpdates.php.

◆ push()

static DeferredUpdates::push	(	array &	$queue,
		DeferrableUpdate	$update )

staticprivate

Parameters

DeferrableUpdate[]	$queue
DeferrableUpdate	$update

Definition at line 152 of file DeferredUpdates.php.

References $queue, and and().

◆ runUpdate()

static DeferredUpdates::runUpdate	(	DeferrableUpdate	$update,
		LBFactory	$lbFactory,
			$mode,
			$stage )

staticprivate

Parameters

DeferrableUpdate	$update
LBFactory	$lbFactory
string	$mode
int	$stage

Returns: ErrorPageError|null

Definition at line 258 of file DeferredUpdates.php.

References $e, and(), Wikimedia\Rdbms\LBFactory\beginMasterChanges(), and Wikimedia\Rdbms\LBFactory\commitMasterChanges().

◆ tryOpportunisticExecute()

static DeferredUpdates::tryOpportunisticExecute ( $mode = 'run' )

static

Run all deferred updates immediately if there are no DB writes active.

If there are many deferred updates pending, $mode is 'run', and there are still busy LBFactory database handles, then any EnqueueableDataUpdate tasks might be enqueued as jobs to be executed later.

Parameters

string $mode Use "enqueue" to use the job queue when possible

Returns: bool Whether updates were allowed to run

Since: 1.28

Definition at line 305 of file DeferredUpdates.php.

Member Data Documentation

◆ $executeContext

array null DeferredUpdates::$executeContext

staticprivate

Information about the current execute() call or null if not running.

Definition at line 69 of file DeferredUpdates.php.

◆ $postSendUpdates

DeferrableUpdate [] DeferredUpdates::$postSendUpdates = []

staticprivate

Updates to be deferred until after request end.

Definition at line 60 of file DeferredUpdates.php.

◆ $preSendUpdates

DeferrableUpdate [] DeferredUpdates::$preSendUpdates = []

staticprivate

Updates to be deferred until before request end.

Definition at line 58 of file DeferredUpdates.php.

◆ ALL

const DeferredUpdates::ALL = 0

Definition at line 62 of file DeferredUpdates.php.

◆ BIG_QUEUE_SIZE

const DeferredUpdates::BIG_QUEUE_SIZE = 100

Definition at line 66 of file DeferredUpdates.php.

◆ POSTSEND

const DeferredUpdates::POSTSEND = 2

Definition at line 64 of file DeferredUpdates.php.

◆ PRESEND

const DeferredUpdates::PRESEND = 1

Definition at line 63 of file DeferredUpdates.php.

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

includes/deferred/DeferredUpdates.php

Static Public Member Functions

Public Attributes

Static Protected Member Functions

Static Private Member Functions

Static Private Attributes

Detailed Description

Member Function Documentation

◆ addCallableUpdate()

◆ addUpdate()

◆ areDatabaseTransactionsActive()

◆ clearPendingUpdates()

◆ doUpdates()

◆ enqueueUpdates()

◆ execute()

◆ getPendingUpdates()

◆ pendingUpdatesCount()

◆ push()

◆ runUpdate()

◆ tryOpportunisticExecute()

Member Data Documentation

◆ $executeContext

◆ $postSendUpdates

◆ $preSendUpdates

◆ ALL

◆ BIG_QUEUE_SIZE

◆ POSTSEND

◆ PRESEND