MediaWiki REL1_33
ILoadBalancer.php
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1<?php
23namespace Wikimedia\Rdbms;
24
25use Exception;
26use InvalidArgumentException;
27
78interface ILoadBalancer {
80 const DB_REPLICA = -1;
82 const DB_MASTER = -2;
83
85 const DOMAIN_ANY = '';
86
88 const CONN_TRX_AUTOCOMMIT = 1;
89
91 const STAGE_POSTCOMMIT_CALLBACKS = 'stage-postcommit-callbacks';
93 const STAGE_POSTROLLBACK_CALLBACKS = 'stage-postrollback-callbacks';
94
121 public function __construct( array $params );
122
130 public function getLocalDomainID();
131
137 public function resolveDomainID( $domain );
138
145 public function redefineLocalDomain( $domain );
146
159 public function getReaderIndex( $group = false, $domain = false );
160
173 public function waitFor( $pos );
174
184 public function waitForOne( $pos, $timeout = null );
185
193 public function waitForAll( $pos, $timeout = null );
194
205 public function getAnyOpenConnection( $i, $flags = 0 );
206
229 public function getConnection( $i, $groups = [], $domain = false, $flags = 0 );
230
240 public function reuseConnection( IDatabase $conn );
241
260 public function getConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
261
280 public function getLazyConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
281
300 public function getMaintenanceConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
301
325 public function openConnection( $i, $domain = false, $flags = 0 );
326
330 public function getWriterIndex();
331
338 public function haveIndex( $i );
339
346 public function isNonZeroLoad( $i );
347
353 public function getServerCount();
354
361 public function getServerName( $i );
362
369 public function getServerInfo( $i );
370
378 public function getServerType( $i );
379
385 public function getServerAttributes( $i );
386
391 public function getMasterPos();
392
397 public function disable();
398
402 public function closeAll();
403
412 public function closeConnection( IDatabase $conn );
413
419 public function commitAll( $fname = __METHOD__ );
420
428 public function finalizeMasterChanges();
429
440
453 public function beginMasterChanges( $fname = __METHOD__ );
454
460 public function commitMasterChanges( $fname = __METHOD__ );
461
468
475
481 public function rollbackMasterChanges( $fname = __METHOD__ );
482
488 public function flushReplicaSnapshots( $fname = __METHOD__ );
489
497 public function flushMasterSnapshots( $fname = __METHOD__ );
498
502 public function hasMasterConnection();
503
508 public function hasMasterChanges();
509
514 public function lastMasterChangeTimestamp();
515
523 public function hasOrMadeRecentMasterChanges( $age = null );
524
530 public function pendingMasterChangeCallers();
531
537 public function getLaggedReplicaMode( $domain = false );
538
547 public function laggedReplicaUsed();
548
555 public function getReadOnlyReason( $domain = false, IDatabase $conn = null );
556
562 public function allowLagged( $mode = null );
563
567 public function pingAll();
568
574 public function forEachOpenConnection( $callback, array $params = [] );
575
581 public function forEachOpenMasterConnection( $callback, array $params = [] );
582
588 public function forEachOpenReplicaConnection( $callback, array $params = [] );
589
600 public function getMaxLag( $domain = false );
601
612 public function getLagTimes( $domain = false );
613
628 public function safeGetLag( IDatabase $conn );
629
640 public function safeWaitForMasterPos( IDatabase $conn, $pos = false, $timeout = 10 );
641
649 public function setTransactionListener( $name, callable $callback = null );
650
657 public function setLocalDomainPrefix( $prefix );
658
671 public function setTableAliases( array $aliases );
672
685 public function setIndexAliases( array $aliases );
686}
if(defined( 'MW_SETUP_CALLBACK')) $fname
Customization point after all loading (constants, functions, classes, DefaultSettings,...
Definition Setup.php:123
null means default in associative array with keys and values unescaped Should be merged with default with a value of false meaning to suppress the attribute in associative array with keys and values unescaped & $options
Definition hooks.txt:1999
Basic database interface for live and lazy-loaded relation database handles.
Definition IDatabase.php:38
Database cluster connection, tracking, load balancing, and transaction manager interface.
approveMasterChanges(array $options)
Perform all pre-commit checks for things like replication safety.
reuseConnection(IDatabase $conn)
Mark a foreign connection as being available for reuse under a different DB domain.
forEachOpenConnection( $callback, array $params=[])
Call a function with each open connection object.
finalizeMasterChanges()
Run pre-commit callbacks and defer execution of post-commit callbacks.
getConnection( $i, $groups=[], $domain=false, $flags=0)
Get a connection handle by server index.
rollbackMasterChanges( $fname=__METHOD__)
Issue ROLLBACK only on master, only if queries were done on connection.
getServerType( $i)
Get DB type of the server with the specified index.
getMaxLag( $domain=false)
Get the hostname and lag time of the most-lagged replica DB.
waitFor( $pos)
Set the master wait position.
safeWaitForMasterPos(IDatabase $conn, $pos=false, $timeout=10)
Wait for a replica DB to reach a specified master position.
runMasterTransactionIdleCallbacks()
Consume and run all pending post-COMMIT/ROLLBACK callbacks and commit dangling transactions.
setTransactionListener( $name, callable $callback=null)
Set a callback via IDatabase::setTransactionListener() on all current and future master connections o...
getReaderIndex( $group=false, $domain=false)
Get the index of the reader connection, which may be a replica DB.
hasOrMadeRecentMasterChanges( $age=null)
Check if this load balancer object had any recent or still pending writes issued against it by this P...
forEachOpenMasterConnection( $callback, array $params=[])
Call a function with each open connection object to a master.
beginMasterChanges( $fname=__METHOD__)
Flush any master transaction snapshots and set DBO_TRX (if DBO_DEFAULT is set)
getReadOnlyReason( $domain=false, IDatabase $conn=null)
getLaggedReplicaMode( $domain=false)
pendingMasterChangeCallers()
Get the list of callers that have pending master changes.
flushMasterSnapshots( $fname=__METHOD__)
Commit all master DB transactions so as to flush any REPEATABLE-READ or SSI snapshots.
getMasterPos()
Get the current master position for chronology control purposes.
haveIndex( $i)
Returns true if the specified index is a valid server index.
hasMasterChanges()
Whether there are pending changes or callbacks in a transaction by this thread.
setTableAliases(array $aliases)
Make certain table names use their own database, schema, and table prefix when passed into SQL querie...
redefineLocalDomain( $domain)
Close all connection and redefine the local domain for testing or schema creation.
__construct(array $params)
Construct a manager of IDatabase connection objects.
commitMasterChanges( $fname=__METHOD__)
Issue COMMIT on all open master connections to flush changes and view snapshots.
forEachOpenReplicaConnection( $callback, array $params=[])
Call a function with each open replica DB connection object.
disable()
Disable this load balancer.
openConnection( $i, $domain=false, $flags=0)
Open a connection to the server given by the specified index.
isNonZeroLoad( $i)
Returns true if the specified index is valid and has non-zero load.
laggedReplicaUsed()
Checks whether the database for generic connections this request was both:
getServerCount()
Get the number of defined servers (not the number of open connections)
getLocalDomainID()
Get the local (and default) database domain ID of connection handles.
getServerInfo( $i)
Return the server info structure for a given index, or false if the index is invalid.
getConnectionRef( $i, $groups=[], $domain=false, $flags=0)
Get a database connection handle reference.
flushReplicaSnapshots( $fname=__METHOD__)
Commit all replica DB transactions so as to flush any REPEATABLE-READ or SSI snapshots.
getMaintenanceConnectionRef( $i, $groups=[], $domain=false, $flags=0)
Get a maintenance database connection handle reference for migrations and schema changes.
setIndexAliases(array $aliases)
Convert certain index names to alternative names before querying the DB.
getLazyConnectionRef( $i, $groups=[], $domain=false, $flags=0)
Get a database connection handle reference without connecting yet.
lastMasterChangeTimestamp()
Get the timestamp of the latest write query done by this thread.
runMasterTransactionListenerCallbacks()
Run all recurring post-COMMIT/ROLLBACK listener callbacks.
setLocalDomainPrefix( $prefix)
Set a new table prefix for the existing local domain ID for testing.
closeConnection(IDatabase $conn)
Close a connection.
commitAll( $fname=__METHOD__)
Commit transactions on all open connections.
allowLagged( $mode=null)
Disables/enables lag checks.
closeAll()
Close all open connections.
getLagTimes( $domain=false)
Get an estimate of replication lag (in seconds) for each server.
waitForOne( $pos, $timeout=null)
Set the master wait position and wait for a "generic" replica DB to catch up to it.
getServerName( $i)
Get the host name or IP address of the server with the specified index.
waitForAll( $pos, $timeout=null)
Set the master wait position and wait for ALL replica DBs to catch up to it.
getAnyOpenConnection( $i, $flags=0)
Get any open connection to a given server index, local or foreign.
safeGetLag(IDatabase $conn)
Get the lag in seconds for a given connection, or zero if this load balancer does not have replicatio...
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const DB_REPLICA
Definition defines.php:25
const DB_MASTER
Definition defines.php:26
$params