MediaWiki  REL1_28
DeferredUpdates Class Reference

Class for managing the deferred updates. More...

Collaboration diagram for DeferredUpdates:

Static Public Member Functions

static addCallableUpdate ($callable, $stage=self::POSTSEND, IDatabase $dbw=null)
 Add a callable update. More...
 
static addUpdate (DeferrableUpdate $update, $stage=self::POSTSEND)
 Add an update to the deferred list to be run later by execute() More...
 
static clearPendingUpdates ()
 Clear all pending updates without performing them. More...
 
static doUpdates ($mode= 'run', $stage=self::ALL)
 Do any deferred updates and clear the list. More...
 
static pendingUpdatesCount ()
 
static setImmediateMode ($value)
 
static tryOpportunisticExecute ($mode= 'run')
 Run all deferred updates immediately if there are no DB writes active. More...
 

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. More...
 

Static Private Member Functions

static areDatabaseTransactionsActive ()
 
static enqueueUpdates (array $updates)
 Enqueue a job for each EnqueueableDataUpdate item and return the other items. More...
 
static push (array &$queue, DeferrableUpdate $update)
 
static runUpdate (DeferrableUpdate $update, LBFactory $lbFactory, $stage)
 

Static Private Attributes

static array null $executeContext
 Information about the current execute() call or null if not running. More...
 
static DeferrableUpdate[] $postSendUpdates = []
 Updates to be deferred until after request end. More...
 
static DeferrableUpdate[] $preSendUpdates = []
 Updates to be deferred until before request end. More...
 

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, updates run immediately if no DB writes are pending. Otherwise, they run when:

  • a) Any waitForReplication() call if no writes are pending on any DB
  • b) A commit happens on Maintenance::getDB( DB_MASTER ) if no writes are pending on any DB
  • c) EnqueueableDataUpdate tasks may enqueue on commit of Maintenance::getDB( DB_MASTER )
  • d) At the completion of Maintenance::execute()

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 50 of file DeferredUpdates.php.

Member Function Documentation

static DeferredUpdates::addCallableUpdate (   $callable,
  $stage = self::POSTSEND,
IDatabase  $dbw = null 
)
static
static DeferredUpdates::areDatabaseTransactionsActive ( )
staticprivate
Returns
bool If a transaction round is active or connection is not ready for commit()

Definition at line 342 of file DeferredUpdates.php.

References $lbFactory, IDatabase\explicitTrxActive(), LoadBalancer\forEachOpenMasterConnection(), use, and IDatabase\writesOrCallbacksPending().

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 334 of file DeferredUpdates.php.

Referenced by UploadFromUrlTestSuite\setUp(), and MediaWikiTestCase\setUp().

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

Do any deferred updates and clear the list.

Parameters
string$modeUse "enqueue" to use the job queue when possible [Default: "run"]
integer$stageDeferredUpdates constant (PRESEND, POSTSEND, or ALL) (since 1.27)

Definition at line 117 of file DeferredUpdates.php.

References execute().

Referenced by JobRunner\executeJob(), RefreshLinks\fixLinksFromArticle(), NamespaceConflictChecker\mergePage(), MediaWiki\preOutputCommit(), MediaWiki\restInPeace(), FileBackendTest\testAsyncWrites(), DeferredUpdatesTest\testDoUpdatesCLI(), DeferredUpdatesTest\testDoUpdatesWeb(), and BagOStuffTest\testReportDupes().

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 307 of file DeferredUpdates.php.

References as, and JobQueueGroup\singleton().

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

Immediately run/queue a list of updates.

Parameters
DeferrableUpdate[]&$queue List of DeferrableUpdate objects
string$modeUse "enqueue" to use the job queue when possible
integer$stageClass constant (PRESEND, POSTSEND) (since 1.28)
Exceptions
ErrorPageErrorHappens on top-level calls
ExceptionHappens on second-level calls

Definition at line 166 of file DeferredUpdates.php.

References $e, $lbFactory, $name, $queue, $services, as, RequestContext\getMain(), key, and MWExceptionHandler\rollbackMasterChangesAndLog().

static DeferredUpdates::pendingUpdatesCount ( )
static
Returns
integer Number of enqueued updates
Since
1.28

Definition at line 326 of file DeferredUpdates.php.

Referenced by EditPageTest\testCreatePageTrx(), and DeferredUpdatesTest\testDoUpdatesWeb().

static DeferredUpdates::push ( array $queue,
DeferrableUpdate  $update 
)
staticprivate
Parameters
DeferrableUpdate[]$queue
DeferrableUpdate$update

Definition at line 142 of file DeferredUpdates.php.

static DeferredUpdates::runUpdate ( DeferrableUpdate  $update,
LBFactory  $lbFactory,
  $stage 
)
staticprivate
Parameters
DeferrableUpdate$update
LBFactory$lbFactory
integer$stage
Returns
ErrorPageError|null

Definition at line 251 of file DeferredUpdates.php.

References $e, LBFactory\beginMasterChanges(), LBFactory\commitMasterChanges(), DeferrableUpdate\doUpdate(), and MWExceptionHandler\rollbackMasterChangesAndLog().

static DeferredUpdates::setImmediateMode (   $value)
static
Parameters
bool$valueWhether to just immediately run updates in addUpdate()
Since
1.28
Deprecated:
1.29 Causes issues in Web-executed jobs - see T165714 and T100085.

Definition at line 134 of file DeferredUpdates.php.

References wfDeprecated().

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

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

If $mode is 'run' but there are busy databates, EnqueueableDataUpdate tasks will be enqueued anyway for the sake of progress.

Parameters
string$modeUse "enqueue" to use the job queue when possible
Returns
bool Whether updates were allowed to run
Since
1.28

Definition at line 279 of file DeferredUpdates.php.

Referenced by Maintenance\setLBFactoryTriggers().

Member Data Documentation

array null DeferredUpdates::$executeContext
staticprivate

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

Definition at line 63 of file DeferredUpdates.php.

DeferrableUpdate [] DeferredUpdates::$postSendUpdates = []
staticprivate

Updates to be deferred until after request end.

Definition at line 54 of file DeferredUpdates.php.

DeferrableUpdate [] DeferredUpdates::$preSendUpdates = []
staticprivate

Updates to be deferred until before request end.

Definition at line 52 of file DeferredUpdates.php.

const DeferredUpdates::ALL = 0

Definition at line 56 of file DeferredUpdates.php.

const DeferredUpdates::BIG_QUEUE_SIZE = 100

Definition at line 60 of file DeferredUpdates.php.


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