MediaWiki REL1_31
ILoadBalancer.php
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1<?php
23namespace Wikimedia\Rdbms;
24
25use Exception;
26use InvalidArgumentException;
27
78interface ILoadBalancer {
80 const DB_REPLICA = -1;
81
86 const DB_PRIMARY = -2;
92
94 const DOMAIN_ANY = '';
95
97 const CONN_TRX_AUTOCOMMIT = 1;
99 const CONN_TRX_AUTO = 1;
100
126 public function __construct( array $params );
127
140 public function getReaderIndex( $group = false, $domain = false );
141
154 public function waitFor( $pos );
155
165 public function waitForOne( $pos, $timeout = null );
166
174 public function waitForAll( $pos, $timeout = null );
175
185 public function getAnyOpenConnection( $i, $flags = 0 );
186
208 public function getConnection( $i, $groups = [], $domain = false, $flags = 0 );
209
219 public function reuseConnection( IDatabase $conn );
220
238 public function getConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
239
257 public function getLazyConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
258
276 public function getMaintenanceConnectionRef( $db, $groups = [], $domain = false, $flags = 0 );
277
300 public function openConnection( $i, $domain = false, $flags = 0 );
301
305 public function getWriterIndex();
306
313 public function haveIndex( $i );
314
321 public function isNonZeroLoad( $i );
322
328 public function getServerCount();
329
336 public function getServerName( $i );
337
345 public function getServerType( $i );
346
353 public function getServerInfo( $i );
354
360 public function getServerAttributes( $i );
361
366 public function getMasterPos();
367
372 public function disable();
373
377 public function closeAll();
378
387 public function closeConnection( IDatabase $conn );
388
394 public function commitAll( $fname = __METHOD__ );
395
402 public function finalizeMasterChanges();
403
414
427 public function beginMasterChanges( $fname = __METHOD__ );
428
434 public function commitMasterChanges( $fname = __METHOD__ );
435
445
451 public function rollbackMasterChanges( $fname = __METHOD__ );
452
461
467 public function flushReplicaSnapshots( $fname = __METHOD__ );
468
472 public function hasMasterConnection();
473
478 public function hasMasterChanges();
479
484 public function lastMasterChangeTimestamp();
485
493 public function hasOrMadeRecentMasterChanges( $age = null );
494
500 public function pendingMasterChangeCallers();
501
507 public function getLaggedReplicaMode( $domain = false );
508
517 public function laggedReplicaUsed();
518
525 public function getReadOnlyReason( $domain = false, IDatabase $conn = null );
526
532 public function allowLagged( $mode = null );
533
537 public function pingAll();
538
544 public function forEachOpenConnection( $callback, array $params = [] );
545
551 public function forEachOpenMasterConnection( $callback, array $params = [] );
552
558 public function forEachOpenReplicaConnection( $callback, array $params = [] );
559
570 public function getMaxLag( $domain = false );
571
582 public function getLagTimes( $domain = false );
583
598 public function safeGetLag( IDatabase $conn );
599
610 public function safeWaitForMasterPos( IDatabase $conn, $pos = false, $timeout = 10 );
611
619 public function setTransactionListener( $name, callable $callback = null );
620
626 public function setDomainPrefix( $prefix );
627
640 public function setTableAliases( array $aliases );
641
655 public function setIndexAliases( array $aliases );
656}
Apache License January AND DISTRIBUTION Definitions License shall mean the terms and conditions for use
if(defined( 'MW_SETUP_CALLBACK')) $fname
Customization point after all loading (constants, functions, classes, DefaultSettings,...
Definition Setup.php:112
the array() calling protocol came about after MediaWiki 1.4rc1.
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:2001
injection txt This is an overview of how MediaWiki makes use of dependency injection The design described here grew from the discussion of RFC T384 The term dependency this means that anything an object needs to operate should be injected from the the object itself should only know narrow no concrete implementation of the logic it relies on The requirement to inject everything typically results in an architecture that based on two main types of and essentially stateless service objects that use other service objects to operate on the value objects As of the beginning MediaWiki is only starting to use the DI approach Much of the code still relies on global state or direct resulting in a highly cyclical dependency which acts as the top level factory for services in MediaWiki which can be used to gain access to default instances of various services MediaWikiServices however also allows new services to be defined and default services to be redefined Services are defined or redefined by providing a callback the instantiator that will return a new instance of the service When it will create an instance of MediaWikiServices and populate it with the services defined in the files listed by thereby bootstrapping the DI framework Per $wgServiceWiringFiles lists includes ServiceWiring php
Definition injection.txt:37
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()
Perform all pre-commit callbacks that remain part of the atomic transactions and disable any post-com...
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.
setDomainPrefix( $prefix)
Set a new table prefix for the existing local domain ID for testing.
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.
suppressTransactionEndCallbacks()
Suppress all pending post-COMMIT/ROLLBACK callbacks.
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)
getMaintenanceConnectionRef( $db, $groups=[], $domain=false, $flags=0)
Get a maintenance database connection handle reference for migrations and schema changes.
pendingMasterChangeCallers()
Get the list of callers that have pending master changes.
getMasterPos()
Get the current master position for chronology control purposes.
haveIndex( $i)
Returns true if the specified index is a valid server index.
hasMasterChanges()
Determine if there are pending changes 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...
__construct(array $params)
Construct a manager of IDatabase connection objects.
commitMasterChanges( $fname=__METHOD__)
Issue COMMIT on all master connections where writes where done.
runMasterPostTrxCallbacks( $type)
Issue all pending post-COMMIT/ROLLBACK callbacks.
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)
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 snapshot.
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.
const DB_MASTER
Request a primary, write-enabled DB connection.
lastMasterChangeTimestamp()
Get the timestamp of the latest write query done by this thread.
const DB_PRIMARY
Request a primary, write-enabled DB connection.
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...
const DB_REPLICA
Definition defines.php:25
$params