ChronologyProtector Class Reference

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

Collaboration diagram for ChronologyProtector:

Public Member Functions
	__construct (BagOStuff $store, array $client)
	initLB (LoadBalancer $lb)
	Initialise a LoadBalancer to give it appropriate chronology protection. More...
	setEnabled ($enabled)
	setWaitEnabled ($enabled)
	shutdown ()
	Notify the ChronologyProtector that the LBFactory is done calling shutdownLB() for now. More...
	shutdownLB (LoadBalancer $lb)
	Notify the ChronologyProtector that the LoadBalancer is about to shut down. More...

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

Protected Attributes
array	$client
	Map of (ip: <IP>, agent: <user-agent>) More...
bool	$enabled = true
	Whether to no-op all method calls. More...
bool	$initialized = false
	Whether the client data was loaded. More...
string	$key
	Storage key name. More...
DBMasterPos[]	$shutdownPositions = []
	Map of (DB master name => position) More...
DBMasterPos[]	$startupPositions = []
	Map of (DB master name => position) More...
BagOStuff	$store
bool	$wait = true
	Whether to check and wait on positions. More...

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 28 of file ChronologyProtector.php.

Constructor & Destructor Documentation

ChronologyProtector::__construct	(	BagOStuff	$store,
		array	$client
	)

Parameters

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

Since

1.27

Definition at line 53 of file ChronologyProtector.php.

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

Member Function Documentation

ChronologyProtector::initLB

(

LoadBalancer

$lb

)

Initialise a LoadBalancer 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 slave 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 slaves are available.

Parameters

LoadBalancer

$lb

Returns

void

Definition at line 89 of file ChronologyProtector.php.

References LoadBalancer\getServerCount(), LoadBalancer\getServerName(), LoadBalancer\getWriterIndex(), initPositions(), LoadBalancer\parentInfo(), LoadBalancer\waitFor(), and wfDebugLog().

ChronologyProtector::initPositions ( )

protected

Load in previous master positions for the client.

Definition at line 192 of file ChronologyProtector.php.

References key, store, and wfDebugLog().

Referenced by initLB().

ChronologyProtector::setEnabled

(

$enabled

)

Parameters

bool

$enabled

Whether to no-op all method calls

Since

1.27

Definition at line 66 of file ChronologyProtector.php.

References $enabled.

Referenced by LBFactory\newChronologyProtector().

ChronologyProtector::setWaitEnabled

(

$enabled

)

Parameters

bool

$enabled

Whether to check and wait on positions

Since

1.27

Definition at line 74 of file ChronologyProtector.php.

References $enabled.

Referenced by LBFactory\newChronologyProtector().

ChronologyProtector::shutdown

(

)

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

May commit chronology data to persistent storage.

Returns

array Empty on success; returns the (db name => position) map on failure

Definition at line 140 of file ChronologyProtector.php.

References $shutdownPositions, as, false, key, store, IExpiringStore\TTL_MINUTE, use, wfDebugLog(), and BagOStuff\WRITE_SYNC.

Referenced by LBFactory\shutdownChronologyProtector().

ChronologyProtector::shutdownLB

(

LoadBalancer

$lb

)

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

Saves replication positions.

Parameters

LoadBalancer

$lb

Returns

void

Definition at line 113 of file ChronologyProtector.php.

References LoadBalancer\getAnyOpenConnection(), LoadBalancer\getServerCount(), LoadBalancer\getServerName(), LoadBalancer\getWriterIndex(), LoadBalancer\parentInfo(), and wfDebugLog().

Referenced by LBFactory\shutdownChronologyProtector().

Member Data Documentation

array ChronologyProtector::$client

protected

Map of (ip: <IP>, agent: <user-agent>)

Definition at line 35 of file ChronologyProtector.php.

Referenced by __construct().

bool ChronologyProtector::$enabled = true

protected

Whether to no-op all method calls.

Definition at line 37 of file ChronologyProtector.php.

Referenced by setEnabled(), and setWaitEnabled().

bool ChronologyProtector::$initialized = false

protected

Whether the client data was loaded.

Definition at line 42 of file ChronologyProtector.php.

string ChronologyProtector::$key

protected

Storage key name.

Definition at line 33 of file ChronologyProtector.php.

DBMasterPos [] ChronologyProtector::$shutdownPositions = []

protected

Map of (DB master name => position)

Definition at line 46 of file ChronologyProtector.php.

Referenced by shutdown().

DBMasterPos [] ChronologyProtector::$startupPositions = []

protected

Map of (DB master name => position)

Definition at line 44 of file ChronologyProtector.php.

BagOStuff ChronologyProtector::$store

protected

Definition at line 30 of file ChronologyProtector.php.

Referenced by __construct().

bool ChronologyProtector::$wait = true

protected

Whether to check and wait on positions.

Definition at line 39 of file ChronologyProtector.php.

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

• includes/db/ChronologyProtector.php