Class for ensuring a consistent ordering of events as seen by the user, despite replication. More...

Inheritance diagram for ChronologyProtector:

Collaboration diagram for ChronologyProtector:

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Public Member Functions
	__construct (BagOStuff $store, array $client, $posTime=null)

	getTouched ( $dbName)

	initLB (ILoadBalancer $lb)
	Initialise a ILoadBalancer to give it appropriate chronology protection.

	setEnabled ( $enabled)

	setLogger (LoggerInterface $logger)

	setWaitEnabled ( $enabled)

	shutdown (callable $workCallback=null, $mode='sync')
	Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.

	shutdownLB (ILoadBalancer $lb)
	Notify the ChronologyProtector that the ILoadBalancer is about to shut down.

Protected Member Functions
	initPositions ()
	Load in previous master positions for the client.

Protected Attributes
string	$clientId
	Hash of client parameters.

bool	$enabled = true
	Whether to no-op all method calls.

bool	$initialized = false
	Whether the client data was loaded.

string	$key
	Storage key name.

LoggerInterface	$logger

DBMasterPos[]	$shutdownPositions = []
	Map of (DB master name => position)

float[]	$shutdownTouchDBs = []
	Map of (DB master name => 1)

DBMasterPos[]	$startupPositions = []
	Map of (DB master name => position)

BagOStuff	$store

bool	$wait = true
	Whether to check and wait on positions.

float null	$waitForPosTime
	Minimum UNIX timestamp of 1+ expected startup positions.

int	$waitForPosTimeout = self::POS_WAIT_TIMEOUT
	Max seconds to wait on positions to appear.

Private Member Functions
	getTouchedKey (BagOStuff $store, $dbName)

Static Private Member Functions
static	mergePositions ( $curValue, array $shutdownPositions)

static	minPosTime ( $data)

Detailed Description

Class for ensuring a consistent ordering of events as seen by the user, despite replication.

Kind of like Hawking's [[Chronology Protection Agency]].

Definition at line 31 of file ChronologyProtector.php.

Constructor & Destructor Documentation

◆ __construct()

ChronologyProtector::__construct	(	BagOStuff	$store,
		array	$client,
			$posTime = `null`
	)

Parameters

BagOStuff	$store
array	$client	Map of (ip: <IP>, agent: <user-agent>)
float	$posTime	UNIX timestamp

Since: 1.27

Definition at line 70 of file ChronologyProtector.php.

References $store, key, BagOStuff\makeGlobalKey(), and store.

Member Function Documentation

◆ getTouched()

ChronologyProtector::getTouched ( $dbName )

Parameters

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

Returns: float|bool UNIX timestamp when client last touched the DB; false if not on record

Since: 1.28

Definition at line 226 of file ChronologyProtector.php.

References getTouchedKey(), and store.

◆ getTouchedKey()

ChronologyProtector::getTouchedKey	(	BagOStuff	$store,
			$dbName
	)

private

Parameters

BagOStuff	$store
string	$dbName

Returns: string

Definition at line 235 of file ChronologyProtector.php.

References $store, and BagOStuff\makeGlobalKey().

Referenced by getTouched(), and shutdown().

◆ initLB()

ChronologyProtector::initLB ( ILoadBalancer $lb )

Initialise a ILoadBalancer to give it appropriate chronology protection.

If the stash has a previous master position recorded, this will try to make sure that the next query to a replica DB of that master will see changes up to that position by delaying execution. The delay may timeout and allow stale data if no non-lagged replica DBs are available.

Parameters

ILoadBalancer $lb

Returns: void

Definition at line 109 of file ChronologyProtector.php.

References ILoadBalancer\getServerCount(), ILoadBalancer\getServerName(), ILoadBalancer\getWriterIndex(), initPositions(), and ILoadBalancer\waitFor().

◆ initPositions()

ChronologyProtector::initPositions ( )

protected

Load in previous master positions for the client.

Definition at line 242 of file ChronologyProtector.php.

References $waitForPosTimeout, key, store, and use.

Referenced by initLB().

◆ mergePositions()

static ChronologyProtector::mergePositions	(		$curValue,
		array	$shutdownPositions
	)

staticprivate

Parameters

array \| bool	$curValue
DBMasterPos[]	$shutdownPositions

Returns: array

Definition at line 308 of file ChronologyProtector.php.

References $shutdownPositions, as, and false.

◆ minPosTime()

static ChronologyProtector::minPosTime ( $data )

staticprivate

Parameters

array | bool $data

Returns: float|null

Definition at line 289 of file ChronologyProtector.php.

References as.

◆ setEnabled()

ChronologyProtector::setEnabled ( $enabled )

Parameters

bool $enabled Whether to no-op all method calls

Since: 1.27

Definition at line 86 of file ChronologyProtector.php.

References $enabled.

◆ setLogger()

ChronologyProtector::setLogger ( LoggerInterface $logger )

Definition at line 78 of file ChronologyProtector.php.

References $logger.

Referenced by LBFactory\getChronologyProtector().

◆ setWaitEnabled()

ChronologyProtector::setWaitEnabled ( $enabled )

Parameters

bool $enabled Whether to check and wait on positions

Since: 1.27

Definition at line 94 of file ChronologyProtector.php.

References $enabled.

◆ shutdown()

ChronologyProtector::shutdown	(	callable	$workCallback = `null`,
			$mode = `'sync'`
	)

Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now.

May commit chronology data to persistent storage.

Parameters

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

Returns: DBMasterPos[] Empty on success; returns the (db name => position) map on failure

Definition at line 158 of file ChronologyProtector.php.

References $shutdownPositions, $store, BagOStuff\addBusyCallback(), as, BagOStuff\get(), BagOStuff\getQoS(), getTouchedKey(), key, BagOStuff\lock(), BagOStuff\set(), store, and BagOStuff\unlock().

Referenced by LBFactory\shutdownChronologyProtector().

◆ shutdownLB()

ChronologyProtector::shutdownLB ( ILoadBalancer $lb )

Notify the ChronologyProtector that the ILoadBalancer is about to shut down.

Saves replication positions.

Parameters

ILoadBalancer $lb

Returns: void

Definition at line 131 of file ChronologyProtector.php.

References ILoadBalancer\getMasterPos(), ILoadBalancer\getServerCount(), ILoadBalancer\getServerName(), ILoadBalancer\getWriterIndex(), and ILoadBalancer\hasOrMadeRecentMasterChanges().

Referenced by LBFactory\shutdownChronologyProtector().

Member Data Documentation

◆ $clientId

string ChronologyProtector::$clientId

protected

Hash of client parameters.

Definition at line 40 of file ChronologyProtector.php.

◆ $enabled

bool ChronologyProtector::$enabled = true

protected

Whether to no-op all method calls.

Definition at line 46 of file ChronologyProtector.php.

Referenced by setEnabled(), and setWaitEnabled().

◆ $initialized

bool ChronologyProtector::$initialized = false

protected

Whether the client data was loaded.

Definition at line 51 of file ChronologyProtector.php.

◆ $key

string ChronologyProtector::$key

protected

Storage key name.

Definition at line 38 of file ChronologyProtector.php.

◆ $logger

LoggerInterface ChronologyProtector::$logger

protected

Definition at line 35 of file ChronologyProtector.php.

Referenced by setLogger().

◆ $shutdownPositions

DBMasterPos [] ChronologyProtector::$shutdownPositions = []

protected

Map of (DB master name => position)

Definition at line 55 of file ChronologyProtector.php.

Referenced by mergePositions(), and shutdown().

◆ $shutdownTouchDBs

float [] ChronologyProtector::$shutdownTouchDBs = []

protected

Map of (DB master name => 1)

Definition at line 57 of file ChronologyProtector.php.

◆ $startupPositions

DBMasterPos [] ChronologyProtector::$startupPositions = []

protected

Map of (DB master name => position)

Definition at line 53 of file ChronologyProtector.php.

◆ $store

BagOStuff ChronologyProtector::$store

protected

Definition at line 33 of file ChronologyProtector.php.

Referenced by __construct(), getTouchedKey(), and shutdown().

◆ $wait

bool ChronologyProtector::$wait = true

protected

Whether to check and wait on positions.

Definition at line 48 of file ChronologyProtector.php.

◆ $waitForPosTime

float null ChronologyProtector::$waitForPosTime

protected

Minimum UNIX timestamp of 1+ expected startup positions.

Definition at line 42 of file ChronologyProtector.php.

◆ $waitForPosTimeout

int ChronologyProtector::$waitForPosTimeout = self::POS_WAIT_TIMEOUT

protected

Max seconds to wait on positions to appear.

Definition at line 44 of file ChronologyProtector.php.

Referenced by initPositions().

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

includes/libs/rdbms/ChronologyProtector.php

Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Static Private Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

Member Function Documentation

◆ getTouched()

◆ getTouchedKey()

◆ initLB()

◆ initPositions()

◆ mergePositions()

◆ minPosTime()

◆ setEnabled()

◆ setLogger()

◆ setWaitEnabled()

◆ shutdown()

◆ shutdownLB()

Member Data Documentation

◆ $clientId

◆ $enabled

◆ $initialized

◆ $key

◆ $logger

◆ $shutdownPositions

◆ $shutdownTouchDBs

◆ $startupPositions

◆ $store

◆ $wait

◆ $waitForPosTime

◆ $waitForPosTimeout