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

Inheritance diagram for LBFactory:

Collaboration diagram for LBFactory:

Public Member Functions
	__construct (array $conf)
	Construct a manager of ILoadBalancer objects. More...

	__destruct ()

	appendPreShutdownTimeAsQuery ($url, $time)
	Append ?cpPosTime parameter to a URL for ChronologyProtector purposes if needed. More...

	beginMasterChanges ($fname=__METHOD__)
	Flush any master transaction snapshots and set DBO_TRX (if DBO_DEFAULT is set) More...

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

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

	commitAndWaitForReplication ($fname, $ticket, array $opts=[])
	Convenience method for safely running commitMasterChanges()/waitForReplication() 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...

	flushReplicaSnapshots ($fname=__METHOD__)
	Commit all replica DB transactions so as to flush any REPEATABLE-READ or SSI snapshot. More...

	getChronologyProtectorTouched ($dbName)

	getEmptyTransactionTicket ($fname)
	Get a token asserting that no transaction writes are active. More...

	getExternalLB ($cluster)

	getMainLB ($domain=false)

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

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

	laggedReplicaUsed ()
	Detemine if any lagged replica DB connection was used. More...

	newExternalLB ($cluster)

	newMainLB ($domain=false)

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

	setAgentName ($agent)

	setDomainPrefix ($prefix)
	Set a new table prefix for the existing local domain ID for testing. More...

	setRequestInfo (array $info)

	setWaitForReplicationListener ($name, callable $callback=null)
	Add a callback to be run in every call to waitForReplication() before waiting. More...

	shutdown ($mode=self::SHUTDOWN_CHRONPROT_SYNC, callable $workCallback=null)
	Prepare all tracked load balancers for shutdown. More...

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

Public Member Functions inherited from ILBFactory
	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...

Protected Member Functions
	baseLoadBalancerParams ()
	Base parameters to LoadBalancer::__construct() More...

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

	getChronologyProtector ()

	getScopedPHPBehaviorForCommit ()
	Make PHP ignore user aborts/disconnects until the returned value leaves scope. More...

	initLoadBalancer (ILoadBalancer $lb)

	shutdownChronologyProtector (ChronologyProtector $cp, $workCallback, $mode)
	Get and record all of the staged DB positions into persistent memory storage. More...

Protected Attributes
string	$agent
	Agent name for query profiling. More...

ChronologyProtector	$chronProt

bool	$cliMode
	Whether this PHP instance is for a CLI script. More...

LoggerInterface	$connLogger

callable	$errorLogger
	Error logger. More...

string	$hostname
	Local hostname of the app server. More...

DatabaseDomain	$localDomain
	Local domain. More...

BagOStuff	$memCache

LoggerInterface	$perfLogger

object string	$profiler
	Class name or object With profileIn/profileOut methods. More...

LoggerInterface	$queryLogger

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

callable[]	$replicationWaitCallbacks = []

LoggerInterface	$replLogger

array	$requestInfo
	Web request information about the client. More...

BagOStuff	$srvCache

mixed	$ticket

TransactionProfiler	$trxProfiler

string bool	$trxRoundId = false
	String if a requested DBO_TRX transaction round is active. More...

WANObjectCache	$wanCache

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

Static Private Attributes
static	$loggerFields

Additional Inherited Members
Public Attributes inherited from ILBFactory
const	SHUTDOWN_CHRONPROT_ASYNC = 1

const	SHUTDOWN_CHRONPROT_SYNC = 2

const	SHUTDOWN_NO_CHRONPROT = 0

Detailed Description

An interface for generating database load balancers.

Definition at line 31 of file LBFactory.php.

Constructor & Destructor Documentation

LBFactory::__construct ( array $conf )

Construct a manager of ILoadBalancer objects.

Sub-classes will extend the required keys in $conf with additional parameters

Parameters

$conf

$params Array with keys:

localDomain: A DatabaseDomain or domain ID string.
readOnlyReason : Reason the master DB is read-only if so [optional]
srvCache : BagOStuff object for server cache [optional]
memCache : BagOStuff object for cluster memory cache [optional]
wanCache : WANObjectCache object [optional]
hostname : The name of the current server [optional]
cliMode: Whether the execution context is a CLI script. [optional]
profiler : Class name or instance with profileIn()/profileOut() methods. [optional]
trxProfiler: TransactionProfiler instance. [optional]
replLogger: PSR-3 logger instance. [optional]
connLogger: PSR-3 logger instance. [optional]
queryLogger: PSR-3 logger instance. [optional]
perfLogger: PSR-3 logger instance. [optional]
errorLogger : Callback that takes an Exception and logs it. [optional]

Exceptions

InvalidArgumentException

Implements ILBFactory.

Definition at line 79 of file LBFactory.php.

References $e, $params, as, WANObjectCache\newEmpty(), DatabaseDomain\newFromId(), and DatabaseDomain\newUnspecified().

LBFactory::__destruct ( )

Definition at line 567 of file LBFactory.php.

References destroy().

Member Function Documentation

LBFactory::appendPreShutdownTimeAsQuery	(	$url,
		$time
	)

Append ?cpPosTime parameter to a URL for ChronologyProtector purposes if needed.

Note that unlike cookies, this works accross domains

Parameters

string	$url
float	$time	UNIX timestamp just before shutdown() was called

Returns: string

Implements ILBFactory.

Definition at line 533 of file LBFactory.php.

References ILBFactory\forEachLB(), ILoadBalancer\getServerCount(), and use.

LBFactory::baseLoadBalancerParams ( )

finalprotected

Base parameters to LoadBalancer::__construct()

Returns: array

Definition at line 486 of file LBFactory.php.

References $agent, $cliMode, $connLogger, $errorLogger, $hostname, $localDomain, $profiler, $queryLogger, $readOnlyReason, $replLogger, $srvCache, $trxProfiler, and $wanCache.

Referenced by LBFactorySingle\__construct(), LBFactorySimple\newLoadBalancer(), and LBFactoryMulti\newLoadBalancer().

LBFactory::beginMasterChanges ( $fname = __METHOD__ )

Flush any master transaction snapshots and set DBO_TRX (if DBO_DEFAULT is set)

The DBO_TRX setting will be reverted to the default in each of these methods:

This allows for custom transaction rounds from any outer transaction scope.

Parameters

string $fname

Exceptions

DBTransactionError

Implements ILBFactory.

Definition at line 191 of file LBFactory.php.

References $fname, and forEachLBCallMethod().

Referenced by commitAndWaitForReplication(), JobRunner\executeJob(), and DeferredUpdates\runUpdate().

LBFactory::closeAll ( )

Close all open database connections on all open load balancers.

Implements ILBFactory.

Definition at line 525 of file LBFactory.php.

References forEachLBCallMethod().

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

Commit open transactions on all connections.

This is useful for two main cases:

a) To commit changes to the masters.
b) To release the snapshot on all connections, master and replica DBs.
Parameters

string $fname Caller name

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

Implements ILBFactory.

Definition at line 186 of file LBFactory.php.

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

LBFactory::commitAndWaitForReplication	(		$fname,
			$ticket,
		array	$opts = `[]`
	)

Convenience method for safely running commitMasterChanges()/waitForReplication()

This will commit and wait unless $ticket indicates it is unsafe to do so

Parameters

string	$fname	Caller name (e.g. METHOD)
mixed	$ticket	Result of getEmptyTransactionTicket()
array	$opts	Options to waitForReplication()

Exceptions

DBReplicationWaitError

Implements ILBFactory.

Definition at line 383 of file LBFactory.php.

References $fname, $trxRoundId, beginMasterChanges(), commitMasterChanges(), and waitForReplication().

Referenced by CategoryMembershipChangeJob\notifyUpdatesForRevision().

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

Exceptions

Exception

Implements ILBFactory.

Definition at line 203 of file LBFactory.php.

References $e, $fname, $options, ILBFactory\forEachLB(), forEachLBCallMethod(), getScopedPHPBehaviorForCommit(), logIfMultiDbTransaction(), ILoadBalancer\runMasterPostTrxCallbacks(), and use.

Referenced by commitAll(), commitAndWaitForReplication(), JobRunner\commitMasterChanges(), DeferredUpdates\runUpdate(), and 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: ILoadBalancer::disable()

Implements ILBFactory.

Definition at line 121 of file LBFactory.php.

References forEachLBCallMethod(), and shutdown().

Referenced by __destruct().

LBFactory::disableChronologyProtection ( )

Disable the ChronologyProtector for all load balancers.

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

Implements ILBFactory.

Definition at line 413 of file LBFactory.php.

References getChronologyProtector().

LBFactory::flushReplicaSnapshots ( $fname = __METHOD__ )

Commit all replica DB transactions so as to flush any REPEATABLE-READ or SSI snapshot.

Parameters

string $fname Caller name

Implements ILBFactory.

Definition at line 182 of file LBFactory.php.

References $fname, and forEachLBCallMethod().

Referenced by JobRunner\executeJob().

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

protected

Call a method of each tracked load balancer.

Parameters

string	$methodName
array	$args

Definition at line 173 of file LBFactory.php.

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

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

LBFactory::getChronologyProtector ( )

protected

Returns: ChronologyProtector

Definition at line 420 of file LBFactory.php.

References $chronProt.

Referenced by disableChronologyProtection(), getChronologyProtectorTouched(), LBFactorySimple\getExternalLB(), LBFactoryMulti\getExternalLB(), LBFactorySimple\getMainLB(), LBFactoryMulti\getMainLB(), and shutdown().

LBFactory::getChronologyProtectorTouched ( $dbName )

Parameters

string $dbName DB master name (e.g. "db1052")

Returns: float|bool UNIX timestamp when client last touched the DB or false if not recent

Implements ILBFactory.

Definition at line 409 of file LBFactory.php.

References getChronologyProtector().

LBFactory::getEmptyTransactionTicket ( $fname )

Get a token asserting that no transaction writes are active.

Parameters

string $fname Caller name (e.g. METHOD)

Returns: mixed A value to pass to commitAndWaitForReplication()

Implements ILBFactory.

Definition at line 372 of file LBFactory.php.

References $ticket, and hasMasterChanges().

LBFactory::getExternalLB ( $cluster )

abstract

See also: ILBFactory::getExternalLB()

Parameters

string $cluster

Returns: LoadBalancer

Implements ILBFactory.

Referenced by waitForReplication().

LBFactory::getMainLB ( $domain = false )

abstract

See also: ILBFactory::getMainLB()

Parameters

bool $domain

Returns: LoadBalancer

Implements ILBFactory.

Referenced by JobRunner\commitMasterChanges(), and waitForReplication().

LBFactory::getScopedPHPBehaviorForCommit ( )

finalprotected

Make PHP ignore user aborts/disconnects until the returned value leaves scope.

This returns null and does nothing in CLI mode.

Returns: ScopedCallback|null

Definition at line 556 of file LBFactory.php.

References use.

Referenced by commitMasterChanges().

LBFactory::hasMasterChanges ( )

Determine if any master connection has pending changes.

Returns: bool

Implements ILBFactory.

Definition at line 269 of file LBFactory.php.

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

Referenced by getEmptyTransactionTicket().

LBFactory::hasOrMadeRecentMasterChanges ( $age = null )

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

Parameters

float $age How many seconds ago is "recent" [defaults to LB lag wait timeout]

Returns: bool

Implements ILBFactory.

Definition at line 287 of file LBFactory.php.

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

LBFactory::initLoadBalancer ( ILoadBalancer $lb )

protected

Parameters

ILoadBalancer $lb

Definition at line 507 of file LBFactory.php.

References ILoadBalancer\beginMasterChanges().

Referenced by LBFactorySingle\__construct(), LBFactorySimple\newLoadBalancer(), and LBFactoryMulti\newLoadBalancer().

LBFactory::laggedReplicaUsed ( )

Detemine if any lagged replica DB connection was used.

Returns: bool

Implements ILBFactory.

Definition at line 278 of file LBFactory.php.

References $ret, ILBFactory\forEachLB(), ILoadBalancer\laggedReplicaUsed(), and use.

LBFactory::logIfMultiDbTransaction ( )

private

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

Definition at line 249 of file LBFactory.php.

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

Referenced by commitMasterChanges().

LBFactory::newExternalLB ( $cluster )

abstract

See also: ILBFactory::newExternalLB()

Parameters

string $cluster

Returns: LoadBalancer

Implements ILBFactory.

LBFactory::newMainLB ( $domain = false )

abstract

See also: ILBFactory::newMainLB()

Parameters

bool $domain

Returns: LoadBalancer

Implements ILBFactory.

LBFactory::rollbackMasterChanges ( $fname = __METHOD__ )

Rollback changes on all master connections.

Parameters

string $fname Caller name

Implements ILBFactory.

Definition at line 236 of file LBFactory.php.

References $fname, ILBFactory\forEachLB(), forEachLBCallMethod(), and ILoadBalancer\runMasterPostTrxCallbacks().

LBFactory::setAgentName ( $agent )

Parameters

string $agent Agent name for query profiling

Implements ILBFactory.

Definition at line 529 of file LBFactory.php.

References $agent.

LBFactory::setDomainPrefix ( $prefix )

Set a new table prefix for the existing local domain ID for testing.

Parameters

string $prefix

Implements ILBFactory.

Definition at line 513 of file LBFactory.php.

References ILBFactory\forEachLB(), ILoadBalancer\setDomainPrefix(), and use.

LBFactory::setRequestInfo ( array $info )

Parameters

array

$info

Map of fields, including:

IPAddress : IP address
UserAgent : User-Agent HTTP header
ChronologyProtection : cookie/header value specifying ChronologyProtector usage

Implements ILBFactory.

Definition at line 546 of file LBFactory.php.

References $requestInfo.

LBFactory::setWaitForReplicationListener	(		$name,
		callable	$callback = `null`
	)

Add a callback to be run in every call to waitForReplication() before waiting.

Callbacks must clear any transactions that they start

Parameters

string	$name	Callback name
callable \| null	$callback	Use null to unset a callback

Implements ILBFactory.

Definition at line 364 of file LBFactory.php.

References $name.

LBFactory::shutdown	(		$mode = `self::SHUTDOWN_CHRONPROT_SYNC`,
		callable	$workCallback = `null`
	)

Prepare all tracked load balancers for shutdown.

Parameters

integer	$mode	One of the class SHUTDOWN_* constants
callable \| null	$workCallback	Work to mask ChronologyProtector writes

Implements ILBFactory.

Definition at line 126 of file LBFactory.php.

References commitMasterChanges(), getChronologyProtector(), and shutdownChronologyProtector().

Referenced by destroy().

LBFactory::shutdownChronologyProtector	(	ChronologyProtector	$cp,
			$workCallback,
			$mode
	)

protected

Get and record all of the staged DB positions into persistent memory storage.

Parameters

ChronologyProtector	$cp
callable \| null	$workCallback	Work to do instead of waiting on syncing positions
string	$mode	One of (sync, async); whether to wait on remote datacenters

Definition at line 456 of file LBFactory.php.

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

Referenced by shutdown().

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

Waits for the replica 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 replica DBs.

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 domain, use the 'domain' 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: