d2e1734390
Update CloneDatabase and unit test callers, which are the only things that are likely to call it. Change-Id: Idbc6d2965cd3828c2c6d23012319bbf0fc3ffa4a
687 lines
26 KiB
PHP
687 lines
26 KiB
PHP
<?php
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/**
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* Database load balancing interface
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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* http://www.gnu.org/copyleft/gpl.html
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*
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* @file
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* @ingroup Database
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*/
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namespace Wikimedia\Rdbms;
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use Exception;
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use InvalidArgumentException;
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/**
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* Database cluster connection, tracking, load balancing, and transaction manager interface
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*
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* A "cluster" is considered to be one master database and zero or more replica databases.
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* Typically, the replica DBs replicate from the master asynchronously. The first node in the
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* "servers" configuration array is always considered the "master". However, this class can still
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* be used when all or some of the "replica" DBs are multi-master peers of the master or even
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* when all the DBs are non-replicating clones of each other holding read-only data. Thus, the
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* role of "master" is in some cases merely nominal.
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*
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* By default, each DB server uses DBO_DEFAULT for its 'flags' setting, unless explicitly set
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* otherwise in configuration. DBO_DEFAULT behavior depends on whether 'cliMode' is set:
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* - In CLI mode, the flag has no effect with regards to LoadBalancer.
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* - In non-CLI mode, the flag causes implicit transactions to be used; the first query on
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* a database starts a transaction on that database. The transactions are meant to remain
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* pending until either commitMasterChanges() or rollbackMasterChanges() is called. The
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* application must have some point where it calls commitMasterChanges() near the end of
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* the PHP request.
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* Every iteration of beginMasterChanges()/commitMasterChanges() is called a "transaction round".
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* Rounds are useful on the master DB connections because they make single-DB (and by and large
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* multi-DB) updates in web requests all-or-nothing. Also, transactions on replica DBs are useful
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* when REPEATABLE-READ or SERIALIZABLE isolation is used because all foriegn keys and constraints
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* hold across separate queries in the DB transaction since the data appears within a consistent
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* point-in-time snapshot.
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*
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* The typical caller will use LoadBalancer::getConnection( DB_* ) to yield a live database
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* connection handle. The choice of which DB server to use is based on pre-defined loads for
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* weighted random selection, adjustments thereof by LoadMonitor, and the amount of replication
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* lag on each DB server. Lag checks might cause problems in certain setups, so they should be
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* tuned in the server configuration maps as follows:
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* - Master + N Replica(s): set 'max lag' to an appropriate threshold for avoiding any database
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* lagged by this much or more. If all DBs are this lagged, then the load balancer considers
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* the cluster to be read-only.
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* - Galera Cluster: Seconds_Behind_Master will be 0, so there probably is nothing to tune.
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* Note that lag is still possible depending on how wsrep-sync-wait is set server-side.
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* - Read-only archive clones: set 'is static' in the server configuration maps. This will
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* treat all such DBs as having 0 lag.
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* - SQL load balancing proxy: any proxy should handle lag checks on its own, so the 'max lag'
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* parameter should probably be set to INF in the server configuration maps. This will make
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* the load balancer ignore whatever it detects as the lag of the logical replica is (which
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* would probably just randomly bounce around).
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*
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* If using a SQL proxy service, it would probably be best to have two proxy hosts for the
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* load balancer to talk to. One would be the 'host' of the master server entry and another for
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* the (logical) replica server entry. The proxy could map the load balancer's "replica" DB to
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* any number of physical replica DBs.
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*
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* @since 1.28
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* @ingroup Database
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*/
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interface ILoadBalancer {
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/** @var int Request a replica DB connection */
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const DB_REPLICA = -1;
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/** @var int Request a master DB connection */
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const DB_MASTER = -2;
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/** @var string Domain specifier when no specific database needs to be selected */
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const DOMAIN_ANY = '';
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/** @var int DB handle should have DBO_TRX disabled and the caller will leave it as such */
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const CONN_TRX_AUTOCOMMIT = 1;
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/** @var string Manager of ILoadBalancer instances is running post-commit callbacks */
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const STAGE_POSTCOMMIT_CALLBACKS = 'stage-postcommit-callbacks';
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/** @var string Manager of ILoadBalancer instances is running post-rollback callbacks */
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const STAGE_POSTROLLBACK_CALLBACKS = 'stage-postrollback-callbacks';
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/**
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* Construct a manager of IDatabase connection objects
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*
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* @param array $params Parameter map with keys:
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* - servers : Required. Array of server info structures.
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* - localDomain: A DatabaseDomain or domain ID string.
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* - loadMonitor : Name of a class used to fetch server lag and load.
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* - readOnlyReason : Reason the master DB is read-only if so [optional]
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* - waitTimeout : Maximum time to wait for replicas for consistency [optional]
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* - maxLag: Avoid replica DB servers with more lag than this [optional]
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* - srvCache : BagOStuff object for server cache [optional]
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* - wanCache : WANObjectCache object [optional]
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* - chronologyCallback: Callback to run before the first connection attempt [optional]
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* - hostname : The name of the current server [optional]
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* - cliMode: Whether the execution context is a CLI script. [optional]
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* - profiler : Class name or instance with profileIn()/profileOut() methods. [optional]
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* - trxProfiler: TransactionProfiler instance. [optional]
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* - replLogger: PSR-3 logger instance. [optional]
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* - connLogger: PSR-3 logger instance. [optional]
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* - queryLogger: PSR-3 logger instance. [optional]
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* - perfLogger: PSR-3 logger instance. [optional]
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* - errorLogger : Callback that takes an Exception and logs it. [optional]
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* - deprecationLogger: Callback to log a deprecation warning. [optional]
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* - roundStage: STAGE_POSTCOMMIT_* class constant; for internal use [optional]
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* @throws InvalidArgumentException
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*/
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public function __construct( array $params );
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/**
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* Get the local (and default) database domain ID of connection handles
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*
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* @see DatabaseDomain
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* @return string Database domain ID; this specifies DB name, schema, and table prefix
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* @since 1.31
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*/
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public function getLocalDomainID();
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/**
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* @param DatabaseDomain|string|bool $domain Database domain
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* @return string Value of $domain if provided or the local domain otherwise
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* @since 1.32
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*/
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public function resolveDomainID( $domain );
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/**
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* Close all connection and redefine the local domain for testing or schema creation
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*
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* @param DatabaseDomain|string $domain
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* @since 1.33
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*/
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public function redefineLocalDomain( $domain );
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/**
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* Get the index of the reader connection, which may be a replica DB
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*
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* This takes into account load ratios and lag times. It should
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* always return a consistent index during a given invocation.
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*
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* Side effect: opens connections to databases
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* @param string|bool $group Query group, or false for the generic reader
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* @param string|bool $domain Domain ID, or false for the current domain
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* @throws DBError
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* @return bool|int|string
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*/
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public function getReaderIndex( $group = false, $domain = false );
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/**
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* Set the master wait position
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*
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* If a DB_REPLICA connection has been opened already, then wait immediately.
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* Otherwise sets a variable telling it to wait if such a connection is opened.
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*
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* This only applies to connections to the generic replica DB for this request.
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* If a timeout happens when waiting, then getLaggedReplicaMode()/laggedReplicaUsed()
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* will return true.
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*
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* @param DBMasterPos|bool $pos Master position or false
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*/
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public function waitFor( $pos );
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/**
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* Set the master wait position and wait for a "generic" replica DB to catch up to it
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*
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* This can be used a faster proxy for waitForAll()
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*
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* @param DBMasterPos|bool $pos Master position or false
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* @param int|null $timeout Max seconds to wait; default is mWaitTimeout
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* @return bool Success (able to connect and no timeouts reached)
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*/
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public function waitForOne( $pos, $timeout = null );
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/**
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* Set the master wait position and wait for ALL replica DBs to catch up to it
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*
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* @param DBMasterPos|bool $pos Master position or false
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* @param int|null $timeout Max seconds to wait; default is mWaitTimeout
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* @return bool Success (able to connect and no timeouts reached)
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*/
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public function waitForAll( $pos, $timeout = null );
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/**
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* Get any open connection to a given server index, local or foreign
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*
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* Use CONN_TRX_AUTOCOMMIT to only look for connections opened with that flag.
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* Avoid the use of begin() or startAtomic() on any such connections.
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*
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* @param int $i Server index or DB_MASTER/DB_REPLICA
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* @param int $flags Bitfield of CONN_* class constants
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* @return Database|bool False if no such connection is open
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*/
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public function getAnyOpenConnection( $i, $flags = 0 );
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/**
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* Get a connection handle by server index
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*
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* The CONN_TRX_AUTOCOMMIT flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
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* (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
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* can be used to check such flags beforehand.
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*
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* If the caller uses $domain or sets CONN_TRX_AUTOCOMMIT in $flags, then it must
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* also call ILoadBalancer::reuseConnection() on the handle when finished using it.
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* In all other cases, this is not necessary, though not harmful either.
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* Avoid the use of begin() or startAtomic() on any such connections.
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*
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* @param int $i Server index (overrides $groups) or DB_MASTER/DB_REPLICA
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* @param array|string|bool $groups Query group(s), or false for the generic reader
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* @param string|bool $domain Domain ID, or false for the current domain
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* @param int $flags Bitfield of CONN_* class constants
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*
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* @note This method throws DBAccessError if ILoadBalancer::disable() was called
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*
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* @throws DBError
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* @return Database
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*/
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public function getConnection( $i, $groups = [], $domain = false, $flags = 0 );
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/**
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* Mark a foreign connection as being available for reuse under a different DB domain
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*
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* This mechanism is reference-counted, and must be called the same number of times
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* as getConnection() to work.
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*
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* @param IDatabase $conn
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* @throws InvalidArgumentException
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*/
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public function reuseConnection( IDatabase $conn );
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/**
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* Get a database connection handle reference
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*
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* The handle's methods simply wrap those of a Database handle
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*
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* The CONN_TRX_AUTOCOMMIT flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
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* (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
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* can be used to check such flags beforehand. Avoid the use of begin() or startAtomic()
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* on any CONN_TRX_AUTOCOMMIT connections.
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*
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* @see ILoadBalancer::getConnection() for parameter information
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*
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* @param int $i Server index or DB_MASTER/DB_REPLICA
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* @param array|string|bool $groups Query group(s), or false for the generic reader
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* @param string|bool $domain Domain ID, or false for the current domain
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* @param int $flags Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTOCOMMIT)
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* @return DBConnRef
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*/
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public function getConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
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/**
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* Get a database connection handle reference without connecting yet
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*
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* The handle's methods simply wrap those of a Database handle
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*
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* The CONN_TRX_AUTOCOMMIT flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
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* (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
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* can be used to check such flags beforehand. Avoid the use of begin() or startAtomic()
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* on any CONN_TRX_AUTOCOMMIT connections.
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*
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* @see ILoadBalancer::getConnection() for parameter information
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*
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* @param int $i Server index or DB_MASTER/DB_REPLICA
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* @param array|string|bool $groups Query group(s), or false for the generic reader
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* @param string|bool $domain Domain ID, or false for the current domain
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* @param int $flags Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTOCOMMIT)
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* @return DBConnRef
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*/
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public function getLazyConnectionRef( $i, $groups = [], $domain = false, $flags = 0 );
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/**
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* Get a maintenance database connection handle reference for migrations and schema changes
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*
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* The handle's methods simply wrap those of a Database handle
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*
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* The CONN_TRX_AUTOCOMMIT flag is ignored for databases with ATTR_DB_LEVEL_LOCKING
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* (e.g. sqlite) in order to avoid deadlocks. ILoadBalancer::getServerAttributes()
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* can be used to check such flags beforehand. Avoid the use of begin() or startAtomic()
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* on any CONN_TRX_AUTOCOMMIT connections.
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*
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* @see ILoadBalancer::getConnection() for parameter information
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*
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* @param int $db Server index or DB_MASTER/DB_REPLICA
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* @param array|string|bool $groups Query group(s), or false for the generic reader
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* @param string|bool $domain Domain ID, or false for the current domain
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* @param int $flags Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTOCOMMIT)
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* @return MaintainableDBConnRef
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*/
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public function getMaintenanceConnectionRef( $db, $groups = [], $domain = false, $flags = 0 );
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/**
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* Open a connection to the server given by the specified index
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*
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* The index must be an actual index into the array. If a connection to the server is
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* already open and not considered an "in use" foreign connection, this simply returns it.
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*
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* Avoid using CONN_TRX_AUTOCOMMIT for databases with ATTR_DB_LEVEL_LOCKING (e.g. sqlite)
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* in order to avoid deadlocks. ILoadBalancer::getServerAttributes() can be used to check
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* such flags beforehand.
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*
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* If the caller uses $domain or sets CONN_TRX_AUTOCOMMIT in $flags, then it must
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* also call ILoadBalancer::reuseConnection() on the handle when finished using it.
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* In all other cases, this is not necessary, though not harmful either.
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* Avoid the use of begin() or startAtomic() on any such connections.
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*
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* @note This method throws DBAccessError if ILoadBalancer::disable() was called
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*
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* @param int $i Server index (does not support DB_MASTER/DB_REPLICA)
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* @param string|bool $domain Domain ID, or false for the current domain
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* @param int $flags Bitfield of CONN_* class constants (e.g. CONN_TRX_AUTOCOMMIT)
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* @return Database|bool Returns false on errors
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* @throws DBAccessError
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*/
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public function openConnection( $i, $domain = false, $flags = 0 );
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/**
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* @return int
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*/
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public function getWriterIndex();
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/**
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* Returns true if the specified index is a valid server index
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*
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* @param int $i
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* @return bool
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*/
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public function haveIndex( $i );
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/**
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* Returns true if the specified index is valid and has non-zero load
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*
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* @param int $i
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* @return bool
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*/
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public function isNonZeroLoad( $i );
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/**
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* Get the number of defined servers (not the number of open connections)
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*
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* @return int
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*/
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public function getServerCount();
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/**
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* Get the host name or IP address of the server with the specified index
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*
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* @param int $i
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* @return string Readable name if available or IP/host otherwise
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*/
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public function getServerName( $i );
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/**
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* Return the server info structure for a given index, or false if the index is invalid.
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* @param int $i
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* @return array|bool
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* @since 1.31
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*/
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public function getServerInfo( $i );
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/**
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* Get DB type of the server with the specified index
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*
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* @param int $i
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* @return string One of (mysql,postgres,sqlite,...) or "unknown" for bad indexes
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* @since 1.30
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*/
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public function getServerType( $i );
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/**
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* @param int $i Server index
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* @return array (Database::ATTRIBUTE_* constant => value) for all such constants
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* @since 1.31
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*/
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public function getServerAttributes( $i );
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/**
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* Get the current master position for chronology control purposes
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* @return DBMasterPos|bool Returns false if not applicable
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*/
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public function getMasterPos();
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/**
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* Disable this load balancer. All connections are closed, and any attempt to
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* open a new connection will result in a DBAccessError.
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*/
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public function disable();
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/**
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* Close all open connections
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*/
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public function closeAll();
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/**
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* Close a connection
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*
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* Using this function makes sure the LoadBalancer knows the connection is closed.
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* If you use $conn->close() directly, the load balancer won't update its state.
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*
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* @param IDatabase $conn
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*/
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public function closeConnection( IDatabase $conn );
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/**
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* Commit transactions on all open connections
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* @param string $fname Caller name
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* @throws DBExpectedError
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*/
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public function commitAll( $fname = __METHOD__ );
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/**
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* Run pre-commit callbacks and defer execution of post-commit callbacks
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*
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* Use this only for mutli-database commits
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*
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* @return int Number of pre-commit callbacks run (since 1.32)
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*/
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public function finalizeMasterChanges();
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/**
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* Perform all pre-commit checks for things like replication safety
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*
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* Use this only for mutli-database commits
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*
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* @param array $options Includes:
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* - maxWriteDuration : max write query duration time in seconds
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* @throws DBTransactionError
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*/
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public function approveMasterChanges( array $options );
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/**
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* Flush any master transaction snapshots and set DBO_TRX (if DBO_DEFAULT is set)
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*
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* The DBO_TRX setting will be reverted to the default in each of these methods:
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* - commitMasterChanges()
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* - rollbackMasterChanges()
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* - commitAll()
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* This allows for custom transaction rounds from any outer transaction scope.
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*
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* @param string $fname
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* @throws DBExpectedError
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*/
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public function beginMasterChanges( $fname = __METHOD__ );
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/**
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* Issue COMMIT on all open master connections to flush changes and view snapshots
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* @param string $fname Caller name
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* @throws DBExpectedError
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*/
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public function commitMasterChanges( $fname = __METHOD__ );
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/**
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* Consume and run all pending post-COMMIT/ROLLBACK callbacks and commit dangling transactions
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*
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* @return Exception|null The first exception or null if there were none
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*/
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public function runMasterTransactionIdleCallbacks();
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/**
|
|
* Run all recurring post-COMMIT/ROLLBACK listener callbacks
|
|
*
|
|
* @return Exception|null The first exception or null if there were none
|
|
*/
|
|
public function runMasterTransactionListenerCallbacks();
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|
|
|
/**
|
|
* Issue ROLLBACK only on master, only if queries were done on connection
|
|
* @param string $fname Caller name
|
|
* @throws DBExpectedError
|
|
*/
|
|
public function rollbackMasterChanges( $fname = __METHOD__ );
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|
|
|
/**
|
|
* Commit all replica DB transactions so as to flush any REPEATABLE-READ or SSI snapshots
|
|
*
|
|
* @param string $fname Caller name
|
|
*/
|
|
public function flushReplicaSnapshots( $fname = __METHOD__ );
|
|
|
|
/**
|
|
* Commit all master DB transactions so as to flush any REPEATABLE-READ or SSI snapshots
|
|
*
|
|
* An error will be thrown if a connection has pending writes or callbacks
|
|
*
|
|
* @param string $fname Caller name
|
|
*/
|
|
public function flushMasterSnapshots( $fname = __METHOD__ );
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|
|
|
/**
|
|
* @return bool Whether a master connection is already open
|
|
*/
|
|
public function hasMasterConnection();
|
|
|
|
/**
|
|
* Whether there are pending changes or callbacks in a transaction by this thread
|
|
* @return bool
|
|
*/
|
|
public function hasMasterChanges();
|
|
|
|
/**
|
|
* Get the timestamp of the latest write query done by this thread
|
|
* @return float|bool UNIX timestamp or false
|
|
*/
|
|
public function lastMasterChangeTimestamp();
|
|
|
|
/**
|
|
* Check if this load balancer object had any recent or still
|
|
* pending writes issued against it by this PHP thread
|
|
*
|
|
* @param float|null $age How many seconds ago is "recent" [defaults to mWaitTimeout]
|
|
* @return bool
|
|
*/
|
|
public function hasOrMadeRecentMasterChanges( $age = null );
|
|
|
|
/**
|
|
* Get the list of callers that have pending master changes
|
|
*
|
|
* @return string[] List of method names
|
|
*/
|
|
public function pendingMasterChangeCallers();
|
|
|
|
/**
|
|
* @note This method will trigger a DB connection if not yet done
|
|
* @param string|bool $domain Domain ID, or false for the current domain
|
|
* @return bool Whether the database for generic connections this request is highly "lagged"
|
|
*/
|
|
public function getLaggedReplicaMode( $domain = false );
|
|
|
|
/**
|
|
* 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
|
|
* @return bool
|
|
*/
|
|
public function laggedReplicaUsed();
|
|
|
|
/**
|
|
* @note This method may trigger a DB connection if not yet done
|
|
* @param string|bool $domain Domain ID, or false for the current domain
|
|
* @param IDatabase|null $conn DB master connection; used to avoid loops [optional]
|
|
* @return string|bool Reason the master is read-only or false if it is not
|
|
*/
|
|
public function getReadOnlyReason( $domain = false, IDatabase $conn = null );
|
|
|
|
/**
|
|
* Disables/enables lag checks
|
|
* @param null|bool $mode
|
|
* @return bool
|
|
*/
|
|
public function allowLagged( $mode = null );
|
|
|
|
/**
|
|
* @return bool
|
|
*/
|
|
public function pingAll();
|
|
|
|
/**
|
|
* Call a function with each open connection object
|
|
* @param callable $callback
|
|
* @param array $params
|
|
*/
|
|
public function forEachOpenConnection( $callback, array $params = [] );
|
|
|
|
/**
|
|
* Call a function with each open connection object to a master
|
|
* @param callable $callback
|
|
* @param array $params
|
|
*/
|
|
public function forEachOpenMasterConnection( $callback, array $params = [] );
|
|
|
|
/**
|
|
* Call a function with each open replica DB connection object
|
|
* @param callable $callback
|
|
* @param array $params
|
|
*/
|
|
public function forEachOpenReplicaConnection( $callback, array $params = [] );
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* @param bool|string $domain Domain ID, or false for the default database
|
|
* @return array ( host, max lag, index of max lagged host )
|
|
*/
|
|
public function getMaxLag( $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
|
|
*
|
|
* @param string|bool $domain
|
|
* @return int[] Map of (server index => float|int|bool)
|
|
*/
|
|
public function getLagTimes( $domain = false );
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* @param IDatabase $conn
|
|
* @return int|bool Returns false on error
|
|
*/
|
|
public function safeGetLag( IDatabase $conn );
|
|
|
|
/**
|
|
* Wait for a replica DB to reach a specified master position
|
|
*
|
|
* This will connect to the master to get an accurate position if $pos is not given
|
|
*
|
|
* @param IDatabase $conn Replica DB
|
|
* @param DBMasterPos|bool $pos Master position; default: current position
|
|
* @param int $timeout Timeout in seconds [optional]
|
|
* @return bool Success
|
|
*/
|
|
public function safeWaitForMasterPos( IDatabase $conn, $pos = false, $timeout = 10 );
|
|
|
|
/**
|
|
* Set a callback via IDatabase::setTransactionListener() on
|
|
* all current and future master connections of this load balancer
|
|
*
|
|
* @param string $name Callback name
|
|
* @param callable|null $callback
|
|
*/
|
|
public function setTransactionListener( $name, callable $callback = null );
|
|
|
|
/**
|
|
* Set a new table prefix for the existing local domain ID for testing
|
|
*
|
|
* @param string $prefix
|
|
* @since 1.33
|
|
*/
|
|
public function setLocalDomainPrefix( $prefix );
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* @param array[] $aliases Map of (table => (dbname, schema, prefix) map)
|
|
*/
|
|
public function setTableAliases( array $aliases );
|
|
|
|
/**
|
|
* Convert certain index names to alternative names before querying the DB
|
|
*
|
|
* Note that this applies to indexes regardless of the table they belong to.
|
|
*
|
|
* This can be employed when an index was renamed X => Y in code, but the new Y-named
|
|
* indexes were not yet built on all DBs. After all the Y-named ones are added by the DBA,
|
|
* the aliases can be removed, and then the old X-named indexes dropped.
|
|
*
|
|
* @param string[] $aliases
|
|
* @return mixed
|
|
* @since 1.31
|
|
*/
|
|
public function setIndexAliases( array $aliases );
|
|
}
|