Database connection, tracking, load balancing, and transaction manager for a cluster. More...

Inheritance diagram for Wikimedia\Rdbms\LoadBalancer:

Collaboration diagram for Wikimedia\Rdbms\LoadBalancer:

[legend]

Public Member Functions
	__construct (array $params)
	Construct a manager of IDatabase connection objects. More...

	__destruct ()

	allowLagged ( $mode=null)
	Disables/enables lag checks. More...

	approveMasterChanges (array $options)
	Perform all pre-commit checks for things like replication safety. More...

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

	closeAll ()
	Close all open connections. More...

	closeConnection (IDatabase $conn)
	Close a connection. More...

	commitAll ( $fname=__METHOD__)
	Commit transactions on all open connections. More...

	commitMasterChanges ( $fname=__METHOD__)
	Issue COMMIT on all master connections where writes where done. More...

	disable ()
	Disable this load balancer. More...

	finalizeMasterChanges ()
	Perform all pre-commit callbacks that remain part of the atomic transactions and disable any post-commit callbacks until runMasterPostTrxCallbacks() More...

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

	forEachOpenConnection ( $callback, array $params=[])
	Call a function with each open connection object. More...

	forEachOpenMasterConnection ( $callback, array $params=[])
	Call a function with each open connection object to a master. More...

	forEachOpenReplicaConnection ( $callback, array $params=[])
	Call a function with each open replica DB connection object. More...

	getAnyOpenConnection ( $i)

	getConnection ( $i, $groups=[], $domain=false, $flags=0)
	Get a connection by index. More...

	getConnectionRef ( $db, $groups=[], $domain=false, $flags=0)
	Get a database connection handle reference. More...

	getLaggedReplicaMode ( $domain=false)

	getLaggedSlaveMode ( $domain=false)

	getLagTimes ( $domain=false)
	Get an estimate of replication lag (in seconds) for each server. More...

	getLazyConnectionRef ( $db, $groups=[], $domain=false, $flags=0)
	Get a database connection handle reference without connecting yet. More...

	getMaintenanceConnectionRef ( $db, $groups=[], $domain=false, $flags=0)
	Get a maintenance database connection handle reference for migrations and schema changes. More...

	getMasterPos ()
	Get the current master position for chronology control purposes. More...

	getMaxLag ( $domain=false)
	Get the hostname and lag time of the most-lagged replica DB. More...

	getReaderIndex ( $group=false, $domain=false)
	Get the index of the reader connection, which may be a replica DB. More...

	getReadOnlyReason ( $domain=false, IDatabase $conn=null)

	getServerCount ()
	Get the number of defined servers (not the number of open connections) More...

	getServerInfo ( $i)

	getServerName ( $i)
	Get the host name or IP address of the server with the specified index. More...

	getServerType ( $i)
	Get DB type of the server with the specified index. More...

	getWriterIndex ()

	hasMasterChanges ()
	Determine if there are pending changes in a transaction by this thread. More...

	hasMasterConnection ()

	hasOrMadeRecentMasterChanges ( $age=null)
	Check if this load balancer object had any recent or still pending writes issued against it by this PHP thread. More...

	haveIndex ( $i)
	Returns true if the specified index is a valid server index. More...

	isNonZeroLoad ( $i)
	Returns true if the specified index is valid and has non-zero load. More...

	laggedReplicaUsed ()
	Checks whether the database for generic connections this request was both: More...

	laggedSlaveUsed ()

	lastMasterChangeTimestamp ()
	Get the timestamp of the latest write query done by this thread. More...

	openConnection ( $i, $domain=false, $flags=0)
	Open a connection to the server given by the specified index. More...

	pendingMasterChangeCallers ()
	Get the list of callers that have pending master changes. More...

	pingAll ()

	reuseConnection ( $conn)
	Mark a foreign connection as being available for reuse under a different DB domain. More...

	rollbackMasterChanges ( $fname=__METHOD__)
	Issue ROLLBACK only on master, only if queries were done on connection. More...

	runMasterPostTrxCallbacks ( $type)
	Issue all pending post-COMMIT/ROLLBACK callbacks. More...

	safeGetLag (IDatabase $conn)
	Get the lag in seconds for a given connection, or zero if this load balancer does not have replication enabled. More...

	safeWaitForMasterPos (IDatabase $conn, $pos=false, $timeout=10)

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

	setServerInfo ( $i, array $serverInfo)

	setTableAliases (array $aliases)
	Make certain table names use their own database, schema, and table prefix when passed into SQL queries pre-escaped and without a qualified database name. More...

	setTransactionListener ( $name, callable $callback=null)
	Set a callback via IDatabase::setTransactionListener() on all current and future master connections of this load balancer. More...

	suppressTransactionEndCallbacks ()
	Suppress all pending post-COMMIT/ROLLBACK callbacks. More...

	waitFor ( $pos)
	Set the master wait position. More...

	waitForAll ( $pos, $timeout=null)
	Set the master wait position and wait for ALL replica DBs to catch up to it. More...

	waitForOne ( $pos, $timeout=null)
	Set the master wait position and wait for a "generic" replica DB to catch up to it. More...

Public Attributes
const	KEY_FOREIGN_FREE = 'foreignFree'

const	KEY_FOREIGN_FREE_NOROUND = 'foreignFreeAutoCommit'

const	KEY_FOREIGN_INUSE = 'foreignInUse'

const	KEY_FOREIGN_INUSE_NOROUND = 'foreignInUseAutoCommit'

const	KEY_LOCAL = 'local'

const	KEY_LOCAL_NOROUND = 'localAutoCommit'

Protected Member Functions
	doWait ( $index, $open=false, $timeout=null)
	Wait for a given replica DB to catch up to the master pos stored in $this. More...

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

	reallyOpenConnection (array $server, $dbNameOverride=false)
	Really opens a connection. More...

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

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

LoggerInterface	$connLogger

LoggerInterface	$perfLogger

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

LoggerInterface	$queryLogger

LoggerInterface	$replLogger

TransactionProfiler	$trxProfiler

Private Member Functions
	applyTransactionRoundFlags (IDatabase $conn)

	getLoadMonitor ()
	Get a LoadMonitor instance. More...

	getRandomNonLagged (array $loads, $domain=false, $maxLag=INF)

	isOpen ( $index)
	Test if the specified index represents an open connection. More...

	masterRunningReadOnly ( $domain, IDatabase $conn=null)

	openForeignConnection ( $i, $domain, $flags=0)
	Open a connection to a foreign DB, or return one if it is already open. More...

	pickReaderIndex (array $loads, $domain=false)

	reportConnectionError ()

	setWaitForPositionIfHigher ( $pos)

	undoTransactionRoundFlags (IDatabase $conn)

Private Attributes
bool	$allReplicasDownMode = false
	Whether the generic reader fell back to a lagged replica DB. More...

ChronologyProtector null	$chronProt

bool	$chronProtInitialized = false

int	$connsOpened = 0
	Total connections opened. More...

bool	$disabled = false

Database	$errorConnection
	DB connection object that caused a problem. More...

callable	$errorLogger
	Exception logger. More...

string	$host
	Current server name. More...

bool	$laggedReplicaMode = false
	Whether the generic reader fell back to a lagged replica DB. More...

ILoadMonitor	$loadMonitor

array	$loadMonitorConfig
	The LoadMonitor configuration. More...

DatabaseDomain	$localDomain
	Local Domain ID and default for selectDB() calls. More...

string	$localDomainIdAlias
	Alternate ID string for the domain instead of DatabaseDomain::getId() More...

bool	$mAllowLagged
	Whether to disregard replica DB lag as a factor in replica DB selection. More...

Database[][][]	$mConns
	Map of (connection category => server index => IDatabase[]) More...

array[]	$mGroupLoads
	Map of (group => server index => weight) More...

string	$mLastError = 'Unknown error'
	The last DB selection or connection error. More...

float[]	$mLoads
	Map of (server index => weight) More...

int	$mReadIndex
	The generic (not query grouped) replica DB index (of $mServers) More...

array[]	$mServers
	Map of (server index => server config array) More...

bool DBMasterPos	$mWaitForPos
	False if not set. More...

int	$mWaitTimeout
	Seconds to spend waiting on replica DB lag to resolve. More...

string bool	$readOnlyReason = false
	Reason the LB is read-only or false if not. More...

BagOStuff	$srvCache

	$tableAliases = []

array[]	$trxRecurringCallbacks = []
	Map of (name => callable) More...

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

WANObjectCache	$wanCache

Detailed Description

Database connection, tracking, load balancing, and transaction manager for a cluster.

Definition at line 41 of file LoadBalancer.php.

Constructor & Destructor Documentation

◆ __construct()

Wikimedia\Rdbms\LoadBalancer::__construct ( array $params )

Construct a manager of IDatabase connection objects.

Parameters

array

$params

Parameter map with keys:

servers : Required. Array of server info structures.
localDomain: A DatabaseDomain or domain ID string.
loadMonitor : Name of a class used to fetch server lag and load.
readOnlyReason : Reason the master DB is read-only if so [optional]
waitTimeout : Maximum time to wait for replicas for consistency [optional]
srvCache : BagOStuff object for server cache [optional]
wanCache : WANObjectCache object [optional]
chronologyProtector: ChronologyProtector 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 Wikimedia\Rdbms\ILoadBalancer.

Reimplemented in Wikimedia\Rdbms\LoadBalancerSingle.

Definition at line 135 of file LoadBalancer.php.

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

◆ __destruct()

Wikimedia\Rdbms\LoadBalancer::__destruct ( )

Definition at line 1718 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\disable().

Member Function Documentation

◆ allowLagged()

Wikimedia\Rdbms\LoadBalancer::allowLagged ( $mode = null )

Disables/enables lag checks.

Parameters

null | bool $mode

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1509 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$mAllowLagged.

◆ applyTransactionRoundFlags()

Wikimedia\Rdbms\LoadBalancer::applyTransactionRoundFlags ( IDatabase $conn )

private

Parameters

IDatabase $conn

Definition at line 1350 of file LoadBalancer.php.

References DBO_DEFAULT, DBO_TRX, Wikimedia\Rdbms\IDatabase\getFlag(), Wikimedia\Rdbms\IDatabase\getLBInfo(), and Wikimedia\Rdbms\IDatabase\setFlag().

Referenced by Wikimedia\Rdbms\LoadBalancer\beginMasterChanges(), and Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ approveMasterChanges()

Wikimedia\Rdbms\LoadBalancer::approveMasterChanges ( array $options )

Perform all pre-commit checks for things like replication safety.

Use this only for mutli-database commits

Parameters

array

$options

Includes:

maxWriteDuration : max write query duration time in seconds

Exceptions

DBTransactionError

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1194 of file LoadBalancer.php.

References $options, $time, Wikimedia\Rdbms\IDatabase\explicitTrxActive(), Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\IDatabase\pendingWriteQueryDuration(), Wikimedia\Rdbms\IDatabase\ping(), use, and Wikimedia\Rdbms\IDatabase\writesOrCallbacksPending().

◆ beginMasterChanges()

Wikimedia\Rdbms\LoadBalancer::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:

commitMasterChanges()
rollbackMasterChanges()
commitAll() This allows for custom transaction rounds from any outer transaction scope.

Parameters

string $fname

Exceptions

DBExpectedError

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1227 of file LoadBalancer.php.

References $e, $fname, Wikimedia\Rdbms\LoadBalancer\applyTransactionRoundFlags(), Wikimedia\Rdbms\Database\flushSnapshot(), Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\Database\setTrxEndCallbackSuppression(), and use.

◆ closeAll()

Wikimedia\Rdbms\LoadBalancer::closeAll ( )

Close all open connections.

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1118 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$host, Wikimedia\Rdbms\IDatabase\close(), Wikimedia\Rdbms\LoadBalancer\forEachOpenConnection(), and Wikimedia\Rdbms\IDatabase\getServer().

Referenced by Wikimedia\Rdbms\LoadBalancer\disable().

◆ closeConnection()

Wikimedia\Rdbms\LoadBalancer::closeConnection ( IDatabase $conn )

Close a connection.

Using this function makes sure the LoadBalancer knows the connection is closed. If you use $conn->close() directly, the load balancer won't update its state.

Parameters

IDatabase $conn

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1136 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$connsOpened, Wikimedia\Rdbms\LoadBalancer\$host, $type, as, Wikimedia\Rdbms\IDatabase\close(), Wikimedia\Rdbms\IDatabase\getLBInfo(), and Wikimedia\Rdbms\LoadBalancer\getServerName().

Referenced by Wikimedia\Rdbms\LoadBalancer\doWait(), and Wikimedia\Rdbms\LoadBalancer\safeWaitForMasterPos().

◆ commitAll()

Wikimedia\Rdbms\LoadBalancer::commitAll ( $fname = __METHOD__ )

Commit transactions on all open connections.

Parameters

string $fname Caller name

Exceptions

DBExpectedError

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1157 of file LoadBalancer.php.

References $e, $fname, Wikimedia\Rdbms\IDatabase\commit(), false, Wikimedia\Rdbms\LoadBalancer\forEachOpenConnection(), Wikimedia\Rdbms\IDatabase\getLBInfo(), Wikimedia\Rdbms\LoadBalancer\undoTransactionRoundFlags(), and use.

◆ commitMasterChanges()

Wikimedia\Rdbms\LoadBalancer::commitMasterChanges ( $fname = __METHOD__ )

Issue COMMIT on all master connections where writes where done.

Parameters

string $fname Caller name

Exceptions

DBExpectedError

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1259 of file LoadBalancer.php.

References $e, $fname, Wikimedia\Rdbms\IDatabase\commit(), false, Wikimedia\Rdbms\IDatabase\flushSnapshot(), Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\LoadBalancer\getScopedPHPBehaviorForCommit(), Wikimedia\Rdbms\LoadBalancer\undoTransactionRoundFlags(), use, and Wikimedia\Rdbms\IDatabase\writesOrCallbacksPending().

◆ disable()

Wikimedia\Rdbms\LoadBalancer::disable ( )

Disable this load balancer.

All connections are closed, and any attempt to open a new connection will result in a DBAccessError.

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1113 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\closeAll().

Referenced by Wikimedia\Rdbms\LoadBalancer\__destruct().

◆ doWait()

Wikimedia\Rdbms\LoadBalancer::doWait	(	$index,
		$open = `false`,
		$timeout = `null`
	)

protected

Wait for a given replica DB to catch up to the master pos stored in $this.

Parameters

int	$index	Server index
bool	$open	Check the server even if a new connection has to be made
int	$timeout	Max seconds to wait; default is mWaitTimeout

Returns: bool

Definition at line 559 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$mWaitTimeout, Wikimedia\Rdbms\LoadBalancer\closeConnection(), Wikimedia\Rdbms\LoadBalancer\getAnyOpenConnection(), Wikimedia\Rdbms\LoadBalancer\getServerName(), Wikimedia\Rdbms\DBMasterPos\hasReached(), Wikimedia\Rdbms\LoadBalancer\openConnection(), and IExpiringStore\TTL_DAY.

Referenced by Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), Wikimedia\Rdbms\LoadBalancer\waitFor(), Wikimedia\Rdbms\LoadBalancer\waitForAll(), and Wikimedia\Rdbms\LoadBalancer\waitForOne().

◆ finalizeMasterChanges()

Wikimedia\Rdbms\LoadBalancer::finalizeMasterChanges ( )

Perform all pre-commit callbacks that remain part of the atomic transactions and disable any post-commit callbacks until runMasterPostTrxCallbacks()

Use this only for mutli-database commits

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1184 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\Database\runOnTransactionPreCommitCallbacks(), and Wikimedia\Rdbms\Database\setTrxEndCallbackSuppression().

◆ flushReplicaSnapshots()

Wikimedia\Rdbms\LoadBalancer::flushReplicaSnapshots ( $fname = __METHOD__ )

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

Parameters

string $fname Caller name

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1378 of file LoadBalancer.php.

References Wikimedia\Rdbms\IDatabase\flushSnapshot(), and Wikimedia\Rdbms\LoadBalancer\forEachOpenReplicaConnection().

◆ forEachOpenConnection()

Wikimedia\Rdbms\LoadBalancer::forEachOpenConnection	(		$callback,
		array	$params = `[]`
	)

Call a function with each open connection object.

Parameters

callable	$callback
array	$params

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1529 of file LoadBalancer.php.

References $params, and as.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeAll(), Wikimedia\Rdbms\LoadBalancer\commitAll(), Wikimedia\Rdbms\LoadBalancer\pingAll(), and Wikimedia\Rdbms\LoadBalancer\setDomainPrefix().

◆ forEachOpenMasterConnection()

Wikimedia\Rdbms\LoadBalancer::forEachOpenMasterConnection	(		$callback,
		array	$params = `[]`
	)

Call a function with each open connection object to a master.

Parameters

callable	$callback
array	$params

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1540 of file LoadBalancer.php.

References $params, as, and Wikimedia\Rdbms\LoadBalancer\getWriterIndex().

◆ forEachOpenReplicaConnection()

Wikimedia\Rdbms\LoadBalancer::forEachOpenReplicaConnection	(		$callback,
		array	$params = `[]`
	)

Call a function with each open replica DB connection object.

Parameters

callable	$callback
array	$params

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1553 of file LoadBalancer.php.

References $params, as, and Wikimedia\Rdbms\LoadBalancer\getWriterIndex().

Referenced by Wikimedia\Rdbms\LoadBalancer\flushReplicaSnapshots().

◆ getAnyOpenConnection()

Wikimedia\Rdbms\LoadBalancer::getAnyOpenConnection ( $i )

Parameters

int $i

Returns: IDatabase|bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 539 of file LoadBalancer.php.

References as.

Referenced by Wikimedia\Rdbms\LoadBalancer\doWait(), Wikimedia\Rdbms\LoadBalancer\getMasterPos(), Wikimedia\Rdbms\LoadBalancer\isOpen(), and Wikimedia\Rdbms\LoadBalancer\safeWaitForMasterPos().

◆ getConnection()

Wikimedia\Rdbms\LoadBalancer::getConnection	(	$i,
		$groups = `[]`,
		$domain = `false`,
		$flags = `0`
	)

Get a connection by index.

Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)

Parameters

int	$i	Server index or DB_MASTER/DB_REPLICA
array \| string \| bool	$groups	Query group(s), or false for the generic reader
string \| bool	$domain	Domain ID, or false for the current domain
int	$flags	Bitfield of CONN_* class constants

Exceptions

DBError

Returns: Database

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 621 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$connsOpened, $flags, Wikimedia\Rdbms\LoadBalancer\$host, Wikimedia\Rdbms\LoadBalancer\$localDomainIdAlias, Wikimedia\Rdbms\LoadBalancer\$mLastError, array(), as, DB_MASTER, DB_REPLICA, false, Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), Wikimedia\Rdbms\LoadBalancer\getReadOnlyReason(), Wikimedia\Rdbms\LoadBalancer\getWriterIndex(), Wikimedia\Rdbms\LoadBalancer\openConnection(), and Wikimedia\Rdbms\LoadBalancer\reportConnectionError().

Referenced by Wikimedia\Rdbms\LoadBalancer\getConnectionRef(), Wikimedia\Rdbms\LoadBalancer\getLaggedReplicaMode(), Wikimedia\Rdbms\LoadBalancer\getMaintenanceConnectionRef(), and Wikimedia\Rdbms\LoadBalancer\masterRunningReadOnly().

◆ getConnectionRef()

Wikimedia\Rdbms\LoadBalancer::getConnectionRef	(	$i,
		$groups = `[]`,
		$domain = `false`,
		$flags = `0`
	)

Get a database connection handle reference.

The handle's methods simply wrap those of a Database handle

Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)

See also: ILoadBalancer::getConnection() for parameter information

Parameters

int	$i	Server index or DB_MASTER/DB_REPLICA
array \| string \| bool	$groups	Query group(s), or false for the generic reader
string \| bool	$domain	Domain ID, or false for the current domain
int	$flags	Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTO)

Returns: DBConnRef

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 749 of file LoadBalancer.php.

References $flags, false, and Wikimedia\Rdbms\LoadBalancer\getConnection().

◆ getLaggedReplicaMode()

Wikimedia\Rdbms\LoadBalancer::getLaggedReplicaMode ( $domain = false )

Note: This method will trigger a DB connection if not yet done

Parameters

string | bool $domain Domain ID, or false for the current domain

Returns: bool Whether the database for generic connections this request is highly "lagged"

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1422 of file LoadBalancer.php.

References $e, Wikimedia\Rdbms\LoadBalancer\$laggedReplicaMode, DB_REPLICA, Wikimedia\Rdbms\LoadBalancer\getConnection(), Wikimedia\Rdbms\LoadBalancer\getServerCount(), and Wikimedia\Rdbms\LoadBalancer\reuseConnection().

Referenced by Wikimedia\Rdbms\LoadBalancer\getLaggedSlaveMode(), and Wikimedia\Rdbms\LoadBalancer\getReadOnlyReason().

◆ getLaggedSlaveMode()

Wikimedia\Rdbms\LoadBalancer::getLaggedSlaveMode ( $domain = false )

Parameters

bool $domain

Returns: bool

Deprecated:: 1.28; use getLaggedReplicaMode()

Definition at line 1444 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\getLaggedReplicaMode().

◆ getLagTimes()

Wikimedia\Rdbms\LoadBalancer::getLagTimes ( $domain = false )

Get an estimate of replication lag (in seconds) for each server.

Results are cached for a short time in memcached/process cache

Values may be "false" if replication is too broken to estimate

Parameters

string | bool $domain

Returns: int[] Map of (server index => float|int|bool)

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1588 of file LoadBalancer.php.

References as, Wikimedia\Rdbms\LoadBalancer\getLoadMonitor(), Wikimedia\Rdbms\LoadBalancer\getServerCount(), and Wikimedia\Rdbms\LoadBalancer\getWriterIndex().

Referenced by Wikimedia\Rdbms\LoadBalancer\getMaxLag(), and Wikimedia\Rdbms\LoadBalancer\getRandomNonLagged().

◆ getLazyConnectionRef()

Wikimedia\Rdbms\LoadBalancer::getLazyConnectionRef	(	$i,
		$groups = `[]`,
		$domain = `false`,
		$flags = `0`
	)

Get a database connection handle reference without connecting yet.

The handle's methods simply wrap those of a Database handle

Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)

See also: ILoadBalancer::getConnection() for parameter information

Parameters

int	$i	Server index or DB_MASTER/DB_REPLICA
array \| string \| bool	$groups	Query group(s), or false for the generic reader
string \| bool	$domain	Domain ID, or false for the current domain
int	$flags	Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTO)

Returns: DBConnRef

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 755 of file LoadBalancer.php.

References $flags, and false.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ getLoadMonitor()

Wikimedia\Rdbms\LoadBalancer::getLoadMonitor ( )

private

Get a LoadMonitor instance.

Returns: ILoadMonitor

Definition at line 242 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$loadMonitor, and class.

Referenced by Wikimedia\Rdbms\LoadBalancer\getLagTimes(), and Wikimedia\Rdbms\LoadBalancer\getReaderIndex().

◆ getMaintenanceConnectionRef()

Wikimedia\Rdbms\LoadBalancer::getMaintenanceConnectionRef	(	$db,
		$groups = `[]`,
		$domain = `false`,
		$flags = `0`
	)

Get a maintenance database connection handle reference for migrations and schema changes.

The handle's methods simply wrap those of a Database handle

Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)

See also: ILoadBalancer::getConnection() for parameter information

Parameters

int	$db	Server index or DB_MASTER/DB_REPLICA
array \| string \| bool	$groups	Query group(s), or false for the generic reader
string \| bool	$domain	Domain ID, or false for the current domain
int	$flags	Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTO)

Returns: MaintainableDBConnRef

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 761 of file LoadBalancer.php.

References $flags, false, and Wikimedia\Rdbms\LoadBalancer\getConnection().

◆ getMasterPos()

Wikimedia\Rdbms\LoadBalancer::getMasterPos ( )

Get the current master position for chronology control purposes.

Returns: DBMasterPos|bool Returns false if not applicable

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1094 of file LoadBalancer.php.

References captcha-old\count, Wikimedia\Rdbms\LoadBalancer\getAnyOpenConnection(), and Wikimedia\Rdbms\LoadBalancer\getWriterIndex().

◆ getMaxLag()

Wikimedia\Rdbms\LoadBalancer::getMaxLag ( $domain = false )

Get the hostname and lag time of the most-lagged replica DB.

This is useful for maintenance scripts that need to throttle their updates. May attempt to open connections to replica DBs on the default DB. If there is no lag, the maximum lag will be reported as -1.

Parameters

bool | string $domain Domain ID, or false for the default database

Returns: array ( host, max lag, index of max lagged host )

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1567 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$host, as, Wikimedia\Rdbms\LoadBalancer\getLagTimes(), and Wikimedia\Rdbms\LoadBalancer\getServerCount().

◆ getRandomNonLagged()

Wikimedia\Rdbms\LoadBalancer::getRandomNonLagged	(	array	$loads,
			$domain = `false`,
			$maxLag = `INF`
	)

private

Parameters

array	$loads
bool \| string	$domain	Domain to get non-lagged for
int	$maxLag	Restrict the maximum allowed lag to this many seconds

Returns: bool|int|string

Definition at line 269 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$host, as, captcha-old\count, Wikimedia\Rdbms\LoadBalancer\getLagTimes(), Wikimedia\Rdbms\LoadBalancer\getServerName(), and ArrayUtils\pickRandom().

Referenced by Wikimedia\Rdbms\LoadBalancer\pickReaderIndex().

◆ getReaderIndex()

Wikimedia\Rdbms\LoadBalancer::getReaderIndex	(	$group = `false`,
		$domain = `false`
	)

Get the index of the reader connection, which may be a replica DB.

This takes into account load ratios and lag times. It should always return a consistent index during a given invocation.

Side effect: opens connections to databases

Parameters

string \| bool	$group	Query group, or false for the generic reader
string \| bool	$domain	Domain ID, or false for the current domain

Exceptions

DBError

Returns: bool|int|string

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 319 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$laggedReplicaMode, Wikimedia\Rdbms\LoadBalancer\$mLoads, Wikimedia\Rdbms\LoadBalancer\$mReadIndex, captcha-old\count, Wikimedia\Rdbms\LoadBalancer\doWait(), Wikimedia\Rdbms\LoadBalancer\getLoadMonitor(), Wikimedia\Rdbms\LoadBalancer\getServerName(), Wikimedia\Rdbms\LoadBalancer\getWriterIndex(), list, and Wikimedia\Rdbms\LoadBalancer\pickReaderIndex().

Referenced by Wikimedia\Rdbms\LoadBalancer\getConnection().

◆ getReadOnlyReason()

Wikimedia\Rdbms\LoadBalancer::getReadOnlyReason	(		$domain = `false`,
		IDatabase	$conn = `null`
	)

Note: This method may trigger a DB connection if not yet done

Parameters

string \| bool	$domain	Domain ID, or false for the current domain
IDatabase \| null	$conn	DB master connection; used to avoid loops [optional]

Returns: string|bool Reason the master is read-only or false if it is not

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1461 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$readOnlyReason, Wikimedia\Rdbms\LoadBalancer\getLaggedReplicaMode(), and Wikimedia\Rdbms\LoadBalancer\masterRunningReadOnly().

Referenced by Wikimedia\Rdbms\LoadBalancer\getConnection().

◆ getScopedPHPBehaviorForCommit()

Wikimedia\Rdbms\LoadBalancer::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 1707 of file LoadBalancer.php.

References use.

Referenced by Wikimedia\Rdbms\LoadBalancer\commitMasterChanges().

◆ getServerCount()

Wikimedia\Rdbms\LoadBalancer::getServerCount ( )

Get the number of defined servers (not the number of open connections)

Returns: int

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1054 of file LoadBalancer.php.

References captcha-old\count.

Referenced by Wikimedia\Rdbms\LoadBalancer\getLaggedReplicaMode(), Wikimedia\Rdbms\LoadBalancer\getLagTimes(), Wikimedia\Rdbms\LoadBalancer\getMaxLag(), Wikimedia\Rdbms\LoadBalancer\safeGetLag(), and Wikimedia\Rdbms\LoadBalancer\safeWaitForMasterPos().

◆ getServerInfo()

Wikimedia\Rdbms\LoadBalancer::getServerInfo ( $i )

Deprecated:: Since 1.30, no alternative

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1077 of file LoadBalancer.php.

References wfDeprecated().

◆ getServerName()

Wikimedia\Rdbms\LoadBalancer::getServerName ( $i )

Get the host name or IP address of the server with the specified index.

Parameters

int $i

Returns: string Readable name if available or IP/host otherwise

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1058 of file LoadBalancer.php.

References $name.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeConnection(), Wikimedia\Rdbms\LoadBalancer\doWait(), Wikimedia\Rdbms\LoadBalancer\getRandomNonLagged(), Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), Wikimedia\Rdbms\LoadBalancer\masterRunningReadOnly(), Wikimedia\Rdbms\LoadBalancer\openConnection(), Wikimedia\Rdbms\LoadBalancer\pickReaderIndex(), and Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ getServerType()

Wikimedia\Rdbms\LoadBalancer::getServerType ( $i )

Get DB type of the server with the specified index.

Parameters

int $i

Returns: string One of (mysql,postgres,sqlite,...) or "unknown" for bad indexes

Since: 1.30

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1070 of file LoadBalancer.php.

◆ getWriterIndex()

Wikimedia\Rdbms\LoadBalancer::getWriterIndex ( )

Returns: int

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1042 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\LoadBalancer\forEachOpenReplicaConnection(), Wikimedia\Rdbms\LoadBalancer\getConnection(), Wikimedia\Rdbms\LoadBalancer\getLagTimes(), Wikimedia\Rdbms\LoadBalancer\getMasterPos(), Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), Wikimedia\Rdbms\LoadBalancer\hasMasterConnection(), Wikimedia\Rdbms\LoadBalancer\masterRunningReadOnly(), Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection(), Wikimedia\Rdbms\LoadBalancer\safeWaitForMasterPos(), and Wikimedia\Rdbms\LoadBalancer\waitForOne().

◆ hasMasterChanges()

Wikimedia\Rdbms\LoadBalancer::hasMasterChanges ( )

Determine if there are pending changes in a transaction by this thread.

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1388 of file LoadBalancer.php.

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

Referenced by Wikimedia\Rdbms\LoadBalancer\hasOrMadeRecentMasterChanges().

◆ hasMasterConnection()

Wikimedia\Rdbms\LoadBalancer::hasMasterConnection ( )

Returns: bool Whether a master connection is already open

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1384 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\getWriterIndex(), and Wikimedia\Rdbms\LoadBalancer\isOpen().

◆ hasOrMadeRecentMasterChanges()

Wikimedia\Rdbms\LoadBalancer::hasOrMadeRecentMasterChanges ( $age = null )

Check if this load balancer object had any recent or still pending writes issued against it by this PHP thread.

Parameters

float $age How many seconds ago is "recent" [defaults to mWaitTimeout]

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1406 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\hasMasterChanges(), and Wikimedia\Rdbms\LoadBalancer\lastMasterChangeTimestamp().

◆ haveIndex()

Wikimedia\Rdbms\LoadBalancer::haveIndex ( $i )

Returns true if the specified index is a valid server index.

Parameters

int $i

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1046 of file LoadBalancer.php.

◆ isNonZeroLoad()

Wikimedia\Rdbms\LoadBalancer::isNonZeroLoad ( $i )

Returns true if the specified index is valid and has non-zero load.

Parameters

int $i

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1050 of file LoadBalancer.php.

◆ isOpen()

Wikimedia\Rdbms\LoadBalancer::isOpen ( $index )

private

Test if the specified index represents an open connection.

Parameters

int $index Server index @access private

Returns: bool

Definition at line 932 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\getAnyOpenConnection().

Referenced by Wikimedia\Rdbms\LoadBalancer\hasMasterConnection().

◆ laggedReplicaUsed()

Wikimedia\Rdbms\LoadBalancer::laggedReplicaUsed ( )

Checks whether the database for generic connections this request was both:

a) Already choosen due to a prior connection attempt
b) Considered highly "lagged"

Note: This method will never cause a new DB connection

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1448 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$laggedReplicaMode.

Referenced by Wikimedia\Rdbms\LoadBalancer\laggedSlaveUsed().

◆ laggedSlaveUsed()

Wikimedia\Rdbms\LoadBalancer::laggedSlaveUsed ( )

Returns: bool

Since: 1.27

Deprecated:: Since 1.28; use laggedReplicaUsed()

Definition at line 1457 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\laggedReplicaUsed().

◆ lastMasterChangeTimestamp()

Wikimedia\Rdbms\LoadBalancer::lastMasterChangeTimestamp ( )

Get the timestamp of the latest write query done by this thread.

Returns: float|bool UNIX timestamp or false

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1397 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\IDatabase\lastDoneWrites(), and use.

Referenced by Wikimedia\Rdbms\LoadBalancer\hasOrMadeRecentMasterChanges().

◆ masterRunningReadOnly()

Wikimedia\Rdbms\LoadBalancer::masterRunningReadOnly	(		$domain,
		IDatabase	$conn = `null`
	)

private

Parameters

string	$domain	Domain ID, or false for the current domain
IDatabase \| null	$conn	DB master connectionl used to avoid loops [optional]

Returns: bool

Definition at line 1484 of file LoadBalancer.php.

References $cache, $e, Wikimedia\Rdbms\LoadBalancer\$wanCache, DB_MASTER, Wikimedia\Rdbms\LoadBalancer\getConnection(), Wikimedia\Rdbms\LoadBalancer\getServerName(), Wikimedia\Rdbms\LoadBalancer\getWriterIndex(), Wikimedia\Rdbms\LoadBalancer\reuseConnection(), and use.

Referenced by Wikimedia\Rdbms\LoadBalancer\getReadOnlyReason().

◆ openConnection()

Wikimedia\Rdbms\LoadBalancer::openConnection	(	$i,
		$domain = `false`,
		$flags = `0`
	)

Open a connection to the server given by the specified index.

The index must be an actual index into the array. If a connection to the server is already open and not considered an "in use" foreign connection, this simply returns it.

Avoid using CONN_TRX_AUTO with sqlite (e.g. check getServerType() first)

Note: If disable() was called on this LoadBalancer, this method will throw a DBAccessError.

Parameters

int	$i	Server index (does not support DB_MASTER/DB_REPLICA)
string \| bool	$domain	Domain ID, or false for the current domain
int	$flags	Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTO)

Returns: Database|bool Returns false on errors

Exceptions

DBAccessError

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 768 of file LoadBalancer.php.

References $flags, Wikimedia\Rdbms\LoadBalancer\$host, Wikimedia\Rdbms\LoadBalancer\$localDomainIdAlias, DBO_TRX, Wikimedia\Rdbms\LoadBalancer\getServerName(), Wikimedia\Rdbms\IDatabase\isOpen(), Wikimedia\Rdbms\LoadBalancer\KEY_LOCAL, Wikimedia\Rdbms\LoadBalancer\KEY_LOCAL_NOROUND, Wikimedia\Rdbms\LoadBalancer\openForeignConnection(), and Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

Referenced by Wikimedia\Rdbms\LoadBalancer\doWait(), Wikimedia\Rdbms\LoadBalancer\getConnection(), Wikimedia\Rdbms\LoadBalancer\pickReaderIndex(), and Wikimedia\Rdbms\LoadBalancer\safeWaitForMasterPos().

◆ openForeignConnection()

Wikimedia\Rdbms\LoadBalancer::openForeignConnection	(	$i,
		$domain,
		$flags = `0`
	)

private

Open a connection to a foreign DB, or return one if it is already open.

Increments a reference count on the returned connection which locks the connection to the requested domain. This reference count can be decremented by calling reuseConnection().

If a connection is open to the appropriate server already, but with the wrong database, it will be switched to the right database and returned, as long as it has been freed first with reuseConnection().

On error, returns false, and the connection which caused the error will be available via $this->errorConnection.

Note: If disable() was called on this LoadBalancer, this method will throw a DBAccessError.

Parameters

int	$i	Server index
string	$domain	Domain ID to open
int	$flags	Class CONN_* constant bitfield

Returns: Database

Definition at line 852 of file LoadBalancer.php.

References $flags, key, Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_FREE, Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_FREE_NOROUND, Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_INUSE, Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_INUSE_NOROUND, Wikimedia\Rdbms\DatabaseDomain\newFromId(), and Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

Referenced by Wikimedia\Rdbms\LoadBalancer\openConnection().

◆ pendingMasterChangeCallers()

Wikimedia\Rdbms\LoadBalancer::pendingMasterChangeCallers ( )

Get the list of callers that have pending master changes.

Returns: string[] List of method names

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1413 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\IDatabase\pendingWriteCallers(), and use.

◆ pickReaderIndex()

Wikimedia\Rdbms\LoadBalancer::pickReaderIndex	(	array	$loads,
			$domain = `false`
	)

private

Parameters

array	$loads	List of server weights
string \| bool	$domain

Returns: array (reader index, lagged replica mode) or false on failure

Definition at line 383 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$laggedReplicaMode, captcha-old\count, false, Wikimedia\Rdbms\LoadBalancer\getRandomNonLagged(), Wikimedia\Rdbms\LoadBalancer\getServerName(), Wikimedia\Rdbms\LoadBalancer\openConnection(), ArrayUtils\pickRandom(), and Wikimedia\Rdbms\LoadBalancer\reuseConnection().

Referenced by Wikimedia\Rdbms\LoadBalancer\getReaderIndex().

◆ pingAll()

Wikimedia\Rdbms\LoadBalancer::pingAll ( )

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1518 of file LoadBalancer.php.

References $success, Wikimedia\Rdbms\LoadBalancer\forEachOpenConnection(), Wikimedia\Rdbms\IDatabase\ping(), and use.

◆ reallyOpenConnection()

Wikimedia\Rdbms\LoadBalancer::reallyOpenConnection	(	array	$server,
			$dbNameOverride = `false`
	)

protected

Really opens a connection.

Uncached. Returns a Database object whether or not the connection was successful. @access private

Parameters

array	$server
string \| bool	$dbNameOverride	Use "" to not select any database

Returns: Database

Exceptions

DBAccessError
InvalidArgumentException

Reimplemented in Wikimedia\Rdbms\LoadBalancerSingle.

Definition at line 951 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openConnection(), and Wikimedia\Rdbms\LoadBalancer\openForeignConnection().

◆ reportConnectionError()

Wikimedia\Rdbms\LoadBalancer::reportConnectionError ( )

private

Exceptions

DBConnectionError

Definition at line 1014 of file LoadBalancer.php.

References $context, Wikimedia\Rdbms\LoadBalancer\$errorConnection, and Wikimedia\Rdbms\LoadBalancer\$mLastError.

Referenced by Wikimedia\Rdbms\LoadBalancer\getConnection().

◆ reuseConnection()

Wikimedia\Rdbms\LoadBalancer::reuseConnection ( $conn )

Mark a foreign connection as being available for reuse under a different DB domain.

This mechanism is reference-counted, and must be called the same number of times as getConnection() to work.

Parameters

IDatabase $conn

Exceptions

InvalidArgumentException

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 690 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_FREE, Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_FREE_NOROUND, Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_INUSE, and Wikimedia\Rdbms\LoadBalancer\KEY_FOREIGN_INUSE_NOROUND.

Referenced by Wikimedia\Rdbms\LoadBalancer\getLaggedReplicaMode(), Wikimedia\Rdbms\LoadBalancer\masterRunningReadOnly(), and Wikimedia\Rdbms\LoadBalancer\pickReaderIndex().

◆ rollbackMasterChanges()

Wikimedia\Rdbms\LoadBalancer::rollbackMasterChanges ( $fname = __METHOD__ )

Issue ROLLBACK only on master, only if queries were done on connection.

Parameters

string $fname Caller name

Exceptions

DBExpectedError

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1326 of file LoadBalancer.php.

References $fname, false, Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\IDatabase\rollback(), Wikimedia\Rdbms\LoadBalancer\undoTransactionRoundFlags(), use, and Wikimedia\Rdbms\IDatabase\writesOrCallbacksPending().

◆ runMasterPostTrxCallbacks()

Wikimedia\Rdbms\LoadBalancer::runMasterPostTrxCallbacks ( $type )

Issue all pending post-COMMIT/ROLLBACK callbacks.

Use this only for mutli-database commits

Parameters

int $type IDatabase::TRIGGER_* constant

Returns: Exception|null The first exception or null if there were none

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1293 of file LoadBalancer.php.

References $e, $type, Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\Database\runOnTransactionIdleCallbacks(), Wikimedia\Rdbms\Database\runTransactionListenerCallbacks(), Wikimedia\Rdbms\Database\setTrxEndCallbackSuppression(), Wikimedia\Rdbms\Database\trxLevel(), use, and Wikimedia\Rdbms\Database\writesOrCallbacksPending().

◆ safeGetLag()

Wikimedia\Rdbms\LoadBalancer::safeGetLag ( IDatabase $conn )

Get the lag in seconds for a given connection, or zero if this load balancer does not have replication enabled.

This should be used in preference to Database::getLag() in cases where replication may not be in use, since there is no way to determine if replication is in use at the connection level without running potentially restricted queries such as SHOW SLAVE STATUS. Using this function instead of Database::getLag() avoids a fatal error in this case on many installations.

Parameters

IDatabase $conn

Returns: int|bool Returns false on error

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1606 of file LoadBalancer.php.

References Wikimedia\Rdbms\IDatabase\getLag(), and Wikimedia\Rdbms\LoadBalancer\getServerCount().

◆ safeWaitForMasterPos()

Wikimedia\Rdbms\LoadBalancer::safeWaitForMasterPos	(	IDatabase	$conn,
			$pos = `false`,
			$timeout = `10`
	)

Parameters

IDatabase	$conn
DBMasterPos \| bool	$pos
int	$timeout

Returns: bool

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1620 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\closeConnection(), Wikimedia\Rdbms\LoadBalancer\getAnyOpenConnection(), Wikimedia\Rdbms\IDatabase\getLBInfo(), Wikimedia\Rdbms\LoadBalancer\getServerCount(), Wikimedia\Rdbms\LoadBalancer\getWriterIndex(), Wikimedia\Rdbms\IDatabase\masterPosWait(), and Wikimedia\Rdbms\LoadBalancer\openConnection().

◆ setDomainPrefix()

Wikimedia\Rdbms\LoadBalancer::setDomainPrefix ( $prefix )

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

Parameters

string $prefix

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1672 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\forEachOpenConnection(), Wikimedia\Rdbms\IDatabase\getDomainID(), Wikimedia\Rdbms\IDatabase\getLBInfo(), Wikimedia\Rdbms\IDatabase\tablePrefix(), and use.

◆ setServerInfo()

Wikimedia\Rdbms\LoadBalancer::setServerInfo	(		$i,
		array	$serverInfo
	)

Deprecated:: Since 1.30, construct new object

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1089 of file LoadBalancer.php.

References wfDeprecated().

◆ setTableAliases()

Wikimedia\Rdbms\LoadBalancer::setTableAliases ( array $aliases )

Make certain table names use their own database, schema, and table prefix when passed into SQL queries pre-escaped and without a qualified database name.

For example, "user" can be converted to "myschema.mydbname.user" for convenience. Appearances like user, somedb.user, somedb.someschema.user will used literally.

Calling this twice will completely clear any old table aliases. Also, note that callers are responsible for making sure the schemas and databases actually exist.

Parameters

array[] $aliases Map of (table => (dbname, schema, prefix) map)

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1668 of file LoadBalancer.php.

◆ setTransactionListener()

Wikimedia\Rdbms\LoadBalancer::setTransactionListener	(		$name,
		callable	$callback = `null`
	)

Set a callback via IDatabase::setTransactionListener() on all current and future master connections of this load balancer.

Parameters

string	$name	Callback name
callable \| null	$callback

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1655 of file LoadBalancer.php.

References $name, Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), Wikimedia\Rdbms\IDatabase\setTransactionListener(), and use.

◆ setWaitForPositionIfHigher()

Wikimedia\Rdbms\LoadBalancer::setWaitForPositionIfHigher ( $pos )

private

Parameters

DBMasterPos | bool $pos

Definition at line 525 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\waitFor().

◆ suppressTransactionEndCallbacks()

Wikimedia\Rdbms\LoadBalancer::suppressTransactionEndCallbacks ( )

Suppress all pending post-COMMIT/ROLLBACK callbacks.

Use this only for mutli-database commits

Returns: Exception|null The first exception or null if there were none

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 1341 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\forEachOpenMasterConnection(), and Wikimedia\Rdbms\Database\setTrxEndCallbackSuppression().

◆ undoTransactionRoundFlags()

Wikimedia\Rdbms\LoadBalancer::undoTransactionRoundFlags ( IDatabase $conn )

private

Parameters

IDatabase $conn

Definition at line 1368 of file LoadBalancer.php.

References DBO_DEFAULT, Wikimedia\Rdbms\IDatabase\getFlag(), Wikimedia\Rdbms\IDatabase\getLBInfo(), and Wikimedia\Rdbms\IDatabase\restoreFlags().

Referenced by Wikimedia\Rdbms\LoadBalancer\commitAll(), Wikimedia\Rdbms\LoadBalancer\commitMasterChanges(), and Wikimedia\Rdbms\LoadBalancer\rollbackMasterChanges().

◆ waitFor()

Wikimedia\Rdbms\LoadBalancer::waitFor ( $pos )

Set the master wait position.

If a DB_REPLICA connection has been opened already, then wait immediately. Otherwise sets a variable telling it to wait if such a connection is opened.

This only applies to connections to the generic replica DB for this request. If a timeout happens when waiting, then getLaggedReplicaMode()/laggedReplicaUsed() will return true.

Parameters

DBMasterPos | bool $pos Master position or false

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 458 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$mReadIndex, Wikimedia\Rdbms\LoadBalancer\$mWaitForPos, Wikimedia\Rdbms\LoadBalancer\doWait(), and Wikimedia\Rdbms\LoadBalancer\setWaitForPositionIfHigher().

◆ waitForAll()

Wikimedia\Rdbms\LoadBalancer::waitForAll	(	$pos,
		$timeout = `null`
	)

Set the master wait position and wait for ALL replica DBs to catch up to it.

Parameters

DBMasterPos \| bool	$pos	Master position or false
int	$timeout	Max seconds to wait; default is mWaitTimeout

Returns: bool Success (able to connect and no timeouts reached)

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 502 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$mWaitForPos, captcha-old\count, and Wikimedia\Rdbms\LoadBalancer\doWait().

◆ waitForOne()

Wikimedia\Rdbms\LoadBalancer::waitForOne	(	$pos,
		$timeout = `null`
	)

Set the master wait position and wait for a "generic" replica DB to catch up to it.

This can be used a faster proxy for waitForAll()

Parameters

DBMasterPos \| bool	$pos	Master position or false
int	$timeout	Max seconds to wait; default is mWaitTimeout

Returns: bool Success (able to connect and no timeouts reached)

Implements Wikimedia\Rdbms\ILoadBalancer.

Definition at line 475 of file LoadBalancer.php.

References Wikimedia\Rdbms\LoadBalancer\$mLoads, Wikimedia\Rdbms\LoadBalancer\$mReadIndex, Wikimedia\Rdbms\LoadBalancer\$mWaitForPos, Wikimedia\Rdbms\LoadBalancer\doWait(), Wikimedia\Rdbms\LoadBalancer\getWriterIndex(), and ArrayUtils\pickRandom().

Member Data Documentation

◆ $agent

string Wikimedia\Rdbms\LoadBalancer::$agent

protected

Agent name for query profiling.

Definition at line 109 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $allReplicasDownMode

bool Wikimedia\Rdbms\LoadBalancer::$allReplicasDownMode = false

private

Whether the generic reader fell back to a lagged replica DB.

Definition at line 89 of file LoadBalancer.php.

◆ $chronProt

ChronologyProtector null Wikimedia\Rdbms\LoadBalancer::$chronProt

private

Definition at line 62 of file LoadBalancer.php.

◆ $chronProtInitialized

bool Wikimedia\Rdbms\LoadBalancer::$chronProtInitialized = false

private

Definition at line 117 of file LoadBalancer.php.

◆ $cliMode

bool Wikimedia\Rdbms\LoadBalancer::$cliMode

protected

Whether this PHP instance is for a CLI script.

Definition at line 107 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $connLogger

LoggerInterface Wikimedia\Rdbms\LoadBalancer::$connLogger

protected

Definition at line 74 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $connsOpened

int Wikimedia\Rdbms\LoadBalancer::$connsOpened = 0

private

Total connections opened.

Definition at line 95 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeConnection(), and Wikimedia\Rdbms\LoadBalancer\getConnection().

◆ $disabled

bool Wikimedia\Rdbms\LoadBalancer::$disabled = false

private

Definition at line 115 of file LoadBalancer.php.

◆ $errorConnection

Database Wikimedia\Rdbms\LoadBalancer::$errorConnection

private

DB connection object that caused a problem.

Definition at line 81 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reportConnectionError().

◆ $errorLogger

callable Wikimedia\Rdbms\LoadBalancer::$errorLogger

private

Exception logger.

Definition at line 112 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $host

string Wikimedia\Rdbms\LoadBalancer::$host

private

Current server name.

Definition at line 105 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\closeAll(), Wikimedia\Rdbms\LoadBalancer\closeConnection(), Wikimedia\Rdbms\LoadBalancer\getConnection(), Wikimedia\Rdbms\LoadBalancer\getMaxLag(), Wikimedia\Rdbms\LoadBalancer\getRandomNonLagged(), and Wikimedia\Rdbms\LoadBalancer\openConnection().

◆ $laggedReplicaMode

bool Wikimedia\Rdbms\LoadBalancer::$laggedReplicaMode = false

private

Whether the generic reader fell back to a lagged replica DB.

Definition at line 87 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getLaggedReplicaMode(), Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), Wikimedia\Rdbms\LoadBalancer\laggedReplicaUsed(), and Wikimedia\Rdbms\LoadBalancer\pickReaderIndex().

◆ $loadMonitor

ILoadMonitor Wikimedia\Rdbms\LoadBalancer::$loadMonitor

private

Definition at line 60 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getLoadMonitor().

◆ $loadMonitorConfig

array Wikimedia\Rdbms\LoadBalancer::$loadMonitorConfig

private

The LoadMonitor configuration.

Definition at line 55 of file LoadBalancer.php.

◆ $localDomain

DatabaseDomain Wikimedia\Rdbms\LoadBalancer::$localDomain

private

Local Domain ID and default for selectDB() calls.

Definition at line 101 of file LoadBalancer.php.

◆ $localDomainIdAlias

string Wikimedia\Rdbms\LoadBalancer::$localDomainIdAlias

private

Alternate ID string for the domain instead of DatabaseDomain::getId()

Definition at line 103 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getConnection(), and Wikimedia\Rdbms\LoadBalancer\openConnection().

◆ $mAllowLagged

bool Wikimedia\Rdbms\LoadBalancer::$mAllowLagged

private

Whether to disregard replica DB lag as a factor in replica DB selection.

Definition at line 51 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\allowLagged().

◆ $mConns

Database [][][] Wikimedia\Rdbms\LoadBalancer::$mConns

private

Map of (connection category => server index => IDatabase[])

Definition at line 45 of file LoadBalancer.php.

◆ $mGroupLoads

array [] Wikimedia\Rdbms\LoadBalancer::$mGroupLoads

private

Map of (group => server index => weight)

Definition at line 49 of file LoadBalancer.php.

◆ $mLastError

string Wikimedia\Rdbms\LoadBalancer::$mLastError = 'Unknown error'

private

The last DB selection or connection error.

Definition at line 91 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getConnection(), and Wikimedia\Rdbms\LoadBalancer\reportConnectionError().

◆ $mLoads

float [] Wikimedia\Rdbms\LoadBalancer::$mLoads

private

Map of (server index => weight)

Definition at line 47 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), and Wikimedia\Rdbms\LoadBalancer\waitForOne().

◆ $mReadIndex

int Wikimedia\Rdbms\LoadBalancer::$mReadIndex

private

The generic (not query grouped) replica DB index (of $mServers)

Definition at line 83 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getReaderIndex(), Wikimedia\Rdbms\LoadBalancer\waitFor(), and Wikimedia\Rdbms\LoadBalancer\waitForOne().

◆ $mServers

array [] Wikimedia\Rdbms\LoadBalancer::$mServers

private

Map of (server index => server config array)

Definition at line 43 of file LoadBalancer.php.

◆ $mWaitForPos

bool DBMasterPos Wikimedia\Rdbms\LoadBalancer::$mWaitForPos

private

False if not set.

Definition at line 85 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\waitFor(), Wikimedia\Rdbms\LoadBalancer\waitForAll(), and Wikimedia\Rdbms\LoadBalancer\waitForOne().

◆ $mWaitTimeout

int Wikimedia\Rdbms\LoadBalancer::$mWaitTimeout

private

Seconds to spend waiting on replica DB lag to resolve.

Definition at line 53 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\doWait().

◆ $perfLogger

LoggerInterface Wikimedia\Rdbms\LoadBalancer::$perfLogger

protected

Definition at line 78 of file LoadBalancer.php.

◆ $profiler

object string Wikimedia\Rdbms\LoadBalancer::$profiler

protected

Class name or object With profileIn/profileOut methods.

Definition at line 68 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $queryLogger

LoggerInterface Wikimedia\Rdbms\LoadBalancer::$queryLogger

protected

Definition at line 76 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $readOnlyReason

string bool Wikimedia\Rdbms\LoadBalancer::$readOnlyReason = false

private

Reason the LB is read-only or false if not.

Definition at line 93 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\getReadOnlyReason().

◆ $replLogger

LoggerInterface Wikimedia\Rdbms\LoadBalancer::$replLogger

protected

Definition at line 72 of file LoadBalancer.php.

◆ $srvCache

BagOStuff Wikimedia\Rdbms\LoadBalancer::$srvCache

private

Definition at line 64 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $tableAliases

Wikimedia\Rdbms\LoadBalancer::$tableAliases = []

private

Definition at line 57 of file LoadBalancer.php.

◆ $trxProfiler

TransactionProfiler Wikimedia\Rdbms\LoadBalancer::$trxProfiler

protected

Definition at line 70 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\reallyOpenConnection().

◆ $trxRecurringCallbacks

array [] Wikimedia\Rdbms\LoadBalancer::$trxRecurringCallbacks = []

private

Map of (name => callable)

Definition at line 99 of file LoadBalancer.php.

◆ $trxRoundId

string bool Wikimedia\Rdbms\LoadBalancer::$trxRoundId = false

private

String if a requested DBO_TRX transaction round is active.

Definition at line 97 of file LoadBalancer.php.

◆ $wanCache

WANObjectCache Wikimedia\Rdbms\LoadBalancer::$wanCache

private

Definition at line 66 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\masterRunningReadOnly().

◆ KEY_FOREIGN_FREE

const Wikimedia\Rdbms\LoadBalancer::KEY_FOREIGN_FREE = 'foreignFree'

Definition at line 128 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openForeignConnection(), and Wikimedia\Rdbms\LoadBalancer\reuseConnection().

◆ KEY_FOREIGN_FREE_NOROUND

const Wikimedia\Rdbms\LoadBalancer::KEY_FOREIGN_FREE_NOROUND = 'foreignFreeAutoCommit'

Definition at line 132 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openForeignConnection(), and Wikimedia\Rdbms\LoadBalancer\reuseConnection().

◆ KEY_FOREIGN_INUSE

const Wikimedia\Rdbms\LoadBalancer::KEY_FOREIGN_INUSE = 'foreignInUse'

Definition at line 129 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openForeignConnection(), and Wikimedia\Rdbms\LoadBalancer\reuseConnection().

◆ KEY_FOREIGN_INUSE_NOROUND

const Wikimedia\Rdbms\LoadBalancer::KEY_FOREIGN_INUSE_NOROUND = 'foreignInUseAutoCommit'

Definition at line 133 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openForeignConnection(), and Wikimedia\Rdbms\LoadBalancer\reuseConnection().

◆ KEY_LOCAL

const Wikimedia\Rdbms\LoadBalancer::KEY_LOCAL = 'local'

Definition at line 127 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openConnection().

◆ KEY_LOCAL_NOROUND

const Wikimedia\Rdbms\LoadBalancer::KEY_LOCAL_NOROUND = 'localAutoCommit'

Definition at line 131 of file LoadBalancer.php.

Referenced by Wikimedia\Rdbms\LoadBalancer\openConnection().

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

includes/libs/rdbms/loadbalancer/LoadBalancer.php

Public Member Functions

Public Attributes

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ __construct()

◆ __destruct()

Member Function Documentation

◆ allowLagged()

◆ applyTransactionRoundFlags()

◆ approveMasterChanges()

◆ beginMasterChanges()

◆ closeAll()

◆ closeConnection()

◆ commitAll()

◆ commitMasterChanges()

◆ disable()

◆ doWait()

◆ finalizeMasterChanges()

◆ flushReplicaSnapshots()

◆ forEachOpenConnection()

◆ forEachOpenMasterConnection()

◆ forEachOpenReplicaConnection()

◆ getAnyOpenConnection()

◆ getConnection()

◆ getConnectionRef()

◆ getLaggedReplicaMode()

◆ getLaggedSlaveMode()

◆ getLagTimes()

◆ getLazyConnectionRef()

◆ getLoadMonitor()

◆ getMaintenanceConnectionRef()

◆ getMasterPos()

◆ getMaxLag()

◆ getRandomNonLagged()

◆ getReaderIndex()

◆ getReadOnlyReason()

◆ getScopedPHPBehaviorForCommit()

◆ getServerCount()

◆ getServerInfo()

◆ getServerName()

◆ getServerType()

◆ getWriterIndex()

◆ hasMasterChanges()

◆ hasMasterConnection()

◆ hasOrMadeRecentMasterChanges()

◆ haveIndex()

◆ isNonZeroLoad()

◆ isOpen()

◆ laggedReplicaUsed()

◆ laggedSlaveUsed()

◆ lastMasterChangeTimestamp()

◆ masterRunningReadOnly()

◆ openConnection()

◆ openForeignConnection()

◆ pendingMasterChangeCallers()

◆ pickReaderIndex()

◆ pingAll()

◆ reallyOpenConnection()

◆ reportConnectionError()

◆ reuseConnection()

◆ rollbackMasterChanges()

◆ runMasterPostTrxCallbacks()

◆ safeGetLag()

◆ safeWaitForMasterPos()

◆ setDomainPrefix()

◆ setServerInfo()

◆ setTableAliases()

◆ setTransactionListener()

◆ setWaitForPositionIfHigher()

◆ suppressTransactionEndCallbacks()

◆ undoTransactionRoundFlags()

◆ waitFor()

◆ waitForAll()

◆ waitForOne()

Member Data Documentation

◆ $agent