9cca05a8e8
These not only make the code more robust, but also help a lot when writing unit tests: if a method is return-typehinted and its class is mocked, the mock method will automatically return a mock of its declared return type. Otherwise it will return null, and developers are forced to manually mock the method if the return value is used by the SUT in a way that doesn't accept null. Depends-On: I628fcb1807133390c7b9b47984f512f5b1ae58d0 Depends-On: I7080bc505f5838b2f51a368da562104e206063b0 Change-Id: I59068cfed10aabf6c6002f9e9312a6ef6e7e9441
2576 lines
86 KiB
PHP
2576 lines
86 KiB
PHP
<?php
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/**
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* Database load balancing manager
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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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*/
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namespace Wikimedia\Rdbms;
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use ArrayUtils;
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use BagOStuff;
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use EmptyBagOStuff;
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use InvalidArgumentException;
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use LogicException;
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use Psr\Log\LoggerInterface;
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use Psr\Log\NullLogger;
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use RuntimeException;
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use Throwable;
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use UnexpectedValueException;
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use WANObjectCache;
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use Wikimedia\RequestTimeout\CriticalSectionProvider;
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use Wikimedia\ScopedCallback;
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/**
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* Database connection, tracking, load balancing, and transaction manager for a cluster
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*
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* @ingroup Database
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*/
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class LoadBalancer implements ILoadBalancer {
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/** @var ILoadMonitor */
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private $loadMonitor;
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/** @var CriticalSectionProvider|null */
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private $csProvider;
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/** @var callable|null Callback to run before the first connection attempt */
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private $chronologyCallback;
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/** @var BagOStuff */
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private $srvCache;
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/** @var WANObjectCache */
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private $wanCache;
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/**
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* @var callable|null An optional callback that returns a ScopedCallback instance,
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* meant to profile the actual query execution in {@see Database::doQuery}
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*/
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private $profiler;
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/** @var TransactionProfiler */
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private $trxProfiler;
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/** @var LoggerInterface */
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private $connLogger;
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/** @var LoggerInterface */
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private $queryLogger;
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/** @var LoggerInterface */
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private $replLogger;
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/** @var LoggerInterface */
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private $perfLogger;
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/** @var callable Exception logger */
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private $errorLogger;
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/** @var callable Deprecation logger */
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private $deprecationLogger;
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/** @var DatabaseDomain Local DB domain ID and default for selectDB() calls */
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private $localDomain;
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/** @var IDatabase[][][] Map of (pool category => server index => domain => IDatabase) */
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private $conns;
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/** @var string|null The name of the DB cluster */
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private $clusterName;
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/** @var array[] Map of (server index => server config array) */
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private $servers;
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/** @var array[] Map of (group => server index => weight) */
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private $groupLoads;
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/** @var int[] Map of (server index => seconds of lag considered "high") */
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private $maxLagByIndex;
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/** @var int Seconds to spend waiting on replica DB lag to resolve */
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private $waitTimeout;
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/** @var array The LoadMonitor configuration */
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private $loadMonitorConfig;
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/** @var int */
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private $maxLag;
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/** @var string|null Default query group to use with getConnection() */
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private $defaultGroup;
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/** @var bool Whether this PHP instance is for a CLI script */
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private $cliMode;
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/** @var string Agent name for query profiling */
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private $agent;
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/** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
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private $tableAliases = [];
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/** @var string[] Map of (index alias => index) */
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private $indexAliases = [];
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/** @var DatabaseDomain[]|string[] Map of (domain alias => DB domain) */
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private $domainAliases = [];
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/** @var callable[] Map of (name => callable) */
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private $trxRecurringCallbacks = [];
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/** @var bool[] Map of (domain => whether to use "temp tables only" mode) */
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private $tempTablesOnlyMode = [];
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/** @var string|bool Explicit DBO_TRX transaction round active or false if none */
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private $trxRoundId = false;
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/** @var string Stage of the current transaction round in the transaction round life-cycle */
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private $trxRoundStage = self::ROUND_CURSORY;
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/** @var Database Connection handle that caused a problem */
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private $errorConnection;
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/** @var int[] The group replica server indexes keyed by group */
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private $readIndexByGroup = [];
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/** @var bool|DBPrimaryPos Replication sync position or false if not set */
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private $waitForPos;
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/** @var bool Whether to disregard replica DB lag as a factor in replica DB selection */
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private $allowLagged = false;
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/** @var bool Whether the generic reader fell back to a lagged replica DB */
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private $laggedReplicaMode = false;
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/** @var string The last DB selection or connection error */
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private $lastError = 'Unknown error';
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/** @var string|bool Reason this instance is read-only or false if not */
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private $readOnlyReason = false;
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/** @var int Total number of new connections ever made with this instance */
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private $connectionCounter = 0;
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/** @var bool */
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private $disabled = false;
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/** @var bool Whether the session consistency callback already executed */
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private $chronologyCallbackTriggered = false;
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/** var int An identifier for this class instance */
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private $id;
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/** @var int|null Integer ID of the managing LBFactory instance or null if none */
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private $ownerId;
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/** @var DatabaseDomain[] Map of (domain ID => domain instance) */
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private $nonLocalDomainCache = [];
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private const INFO_SERVER_INDEX = 'serverIndex';
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private const INFO_AUTOCOMMIT_ONLY = 'autoCommitOnly';
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private const INFO_FORIEGN = 'foreign';
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private const INFO_FOREIGN_REF_COUNT = 'foreignPoolRefCount';
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/**
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* Default 'maxLag' when unspecified
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* @internal Only for use within LoadBalancer/LoadMonitor
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*/
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public const MAX_LAG_DEFAULT = 6;
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/** Warn when this many connection are held */
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private const CONN_HELD_WARN_THRESHOLD = 10;
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/** Default 'waitTimeout' when unspecified */
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private const MAX_WAIT_DEFAULT = 10;
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/** Seconds to cache primary DB server read-only status */
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private const TTL_CACHE_READONLY = 5;
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private const KEY_LOCAL = 'local';
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private const KEY_FOREIGN_FREE = 'foreignFree';
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private const KEY_FOREIGN_INUSE = 'foreignInUse';
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private const KEY_LOCAL_NOROUND = 'localAutoCommit';
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private const KEY_FOREIGN_FREE_NOROUND = 'foreignFreeAutoCommit';
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private const KEY_FOREIGN_INUSE_NOROUND = 'foreignInUseAutoCommit';
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private const KEY_LOCAL_DOMAIN = '__local__';
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/** Transaction round, explicit or implicit, has not finished writing */
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private const ROUND_CURSORY = 'cursory';
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/** Transaction round writes are complete and ready for pre-commit checks */
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private const ROUND_FINALIZED = 'finalized';
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/** Transaction round passed final pre-commit checks */
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private const ROUND_APPROVED = 'approved';
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/** Transaction round was committed and post-commit callbacks must be run */
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private const ROUND_COMMIT_CALLBACKS = 'commit-callbacks';
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/** Transaction round was rolled back and post-rollback callbacks must be run */
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private const ROUND_ROLLBACK_CALLBACKS = 'rollback-callbacks';
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/** Transaction round encountered an error */
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private const ROUND_ERROR = 'error';
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/** @var int Idiom for getExistingReaderIndex() meaning "no index selected" */
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private const READER_INDEX_NONE = -1;
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public function __construct( array $params ) {
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if ( !isset( $params['servers'] ) || !count( $params['servers'] ) ) {
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throw new InvalidArgumentException( 'Missing or empty "servers" parameter' );
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}
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$localDomain = isset( $params['localDomain'] )
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? DatabaseDomain::newFromId( $params['localDomain'] )
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: DatabaseDomain::newUnspecified();
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$this->setLocalDomain( $localDomain );
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$this->maxLag = $params['maxLag'] ?? self::MAX_LAG_DEFAULT;
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$listKey = -1;
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$this->servers = [];
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$this->groupLoads = [ self::GROUP_GENERIC => [] ];
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foreach ( $params['servers'] as $i => $server ) {
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if ( ++$listKey !== $i ) {
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throw new UnexpectedValueException( 'List expected for "servers" parameter' );
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}
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$this->servers[$i] = $server;
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foreach ( ( $server['groupLoads'] ?? [] ) as $group => $ratio ) {
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$this->groupLoads[$group][$i] = $ratio;
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}
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$this->groupLoads[self::GROUP_GENERIC][$i] = $server['load'];
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$this->maxLagByIndex[$i] = $server['max lag'] ?? $this->maxLag;
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}
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$this->waitTimeout = $params['waitTimeout'] ?? self::MAX_WAIT_DEFAULT;
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$this->conns = self::newTrackedConnectionsArray();
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if ( isset( $params['readOnlyReason'] ) && is_string( $params['readOnlyReason'] ) ) {
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$this->readOnlyReason = $params['readOnlyReason'];
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}
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$this->loadMonitorConfig = $params['loadMonitor'] ?? [ 'class' => 'LoadMonitorNull' ];
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$this->loadMonitorConfig += [ 'lagWarnThreshold' => $this->maxLag ];
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$this->srvCache = $params['srvCache'] ?? new EmptyBagOStuff();
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$this->wanCache = $params['wanCache'] ?? WANObjectCache::newEmpty();
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$this->errorLogger = $params['errorLogger'] ?? static function ( Throwable $e ) {
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trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
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};
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$this->deprecationLogger = $params['deprecationLogger'] ?? static function ( $msg ) {
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trigger_error( $msg, E_USER_DEPRECATED );
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};
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$this->replLogger = $params['replLogger'] ?? new NullLogger();
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$this->connLogger = $params['connLogger'] ?? new NullLogger();
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$this->queryLogger = $params['queryLogger'] ?? new NullLogger();
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$this->perfLogger = $params['perfLogger'] ?? new NullLogger();
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$this->clusterName = $params['clusterName'] ?? null;
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$this->profiler = $params['profiler'] ?? null;
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$this->trxProfiler = $params['trxProfiler'] ?? new TransactionProfiler();
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$this->csProvider = $params['criticalSectionProvider'] ?? null;
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$this->cliMode = $params['cliMode'] ?? ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' );
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$this->agent = $params['agent'] ?? '';
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if ( isset( $params['chronologyCallback'] ) ) {
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$this->chronologyCallback = $params['chronologyCallback'];
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}
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if ( isset( $params['roundStage'] ) ) {
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if ( $params['roundStage'] === self::STAGE_POSTCOMMIT_CALLBACKS ) {
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$this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
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} elseif ( $params['roundStage'] === self::STAGE_POSTROLLBACK_CALLBACKS ) {
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$this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
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}
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}
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$group = $params['defaultGroup'] ?? self::GROUP_GENERIC;
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$this->defaultGroup = isset( $this->groupLoads[$group] ) ? $group : self::GROUP_GENERIC;
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static $nextId;
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$this->id = $nextId = ( is_int( $nextId ) ? $nextId++ : mt_rand() );
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$this->ownerId = $params['ownerId'] ?? null;
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}
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private static function newTrackedConnectionsArray() {
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return [
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// Connection were transaction rounds may be applied
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self::KEY_LOCAL => [],
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self::KEY_FOREIGN_INUSE => [],
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self::KEY_FOREIGN_FREE => [],
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// Auto-committing counterpart connections that ignore transaction rounds
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self::KEY_LOCAL_NOROUND => [],
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self::KEY_FOREIGN_INUSE_NOROUND => [],
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self::KEY_FOREIGN_FREE_NOROUND => []
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];
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}
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public function getClusterName() {
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if ( $this->clusterName !== null ) {
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$name = $this->clusterName;
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} else {
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// Fallback to the current master name if not specified
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$name = $this->getServerName( $this->getWriterIndex() );
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}
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return $name;
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}
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public function getLocalDomainID() {
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return $this->localDomain->getId();
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}
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public function resolveDomainID( $domain ) {
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return $this->resolveDomainInstance( $domain )->getId();
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}
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/**
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* @param DatabaseDomain|string|bool $domain
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* @return DatabaseDomain
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*/
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final protected function resolveDomainInstance( $domain ) {
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if ( $domain instanceof DatabaseDomain ) {
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return $domain; // already a domain instance
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} elseif ( $domain === false || $domain === $this->localDomain->getId() ) {
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return $this->localDomain;
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} elseif ( isset( $this->domainAliases[$domain] ) ) {
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$this->domainAliases[$domain] =
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DatabaseDomain::newFromId( $this->domainAliases[$domain] );
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return $this->domainAliases[$domain];
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}
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$cachedDomain = $this->nonLocalDomainCache[$domain] ?? null;
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if ( $cachedDomain === null ) {
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$cachedDomain = DatabaseDomain::newFromId( $domain );
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$this->nonLocalDomainCache = [ $domain => $cachedDomain ];
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}
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return $cachedDomain;
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}
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/**
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* Resolve $groups into a list of query groups defining as having database servers
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*
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* @param string[]|string|bool $groups Query group(s) in preference order, [], or false
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* @param int $i Specific server index or DB_PRIMARY/DB_REPLICA
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* @return string[] Non-empty group list in preference order with the default group appended
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*/
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private function resolveGroups( $groups, $i ) {
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// If a specific replica server was specified, then $groups makes no sense
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if ( $i > 0 && $groups !== [] && $groups !== false ) {
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$list = implode( ', ', (array)$groups );
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throw new LogicException( "Query group(s) ($list) given with server index (#$i)" );
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}
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if ( $groups === [] || $groups === false || $groups === $this->defaultGroup ) {
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$resolvedGroups = [ $this->defaultGroup ]; // common case
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} elseif ( is_string( $groups ) && isset( $this->groupLoads[$groups] ) ) {
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$resolvedGroups = [ $groups, $this->defaultGroup ];
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} elseif ( is_array( $groups ) ) {
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$resolvedGroups = $groups;
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if ( array_search( $this->defaultGroup, $resolvedGroups ) === false ) {
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$resolvedGroups[] = $this->defaultGroup;
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}
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} else {
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$resolvedGroups = [ $this->defaultGroup ];
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}
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return $resolvedGroups;
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}
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/**
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* @param int $flags Bitfield of class CONN_* constants
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* @param int $i Specific server index or DB_PRIMARY/DB_REPLICA
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* @param string $domain Database domain
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* @return int Sanitized bitfield
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*/
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private function sanitizeConnectionFlags( $flags, $i, $domain ) {
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// Whether an outside caller is explicitly requesting the primary database server
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if ( $i === self::DB_PRIMARY || $i === $this->getWriterIndex() ) {
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$flags |= self::CONN_INTENT_WRITABLE;
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}
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if ( self::fieldHasBit( $flags, self::CONN_TRX_AUTOCOMMIT ) ) {
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// Callers use CONN_TRX_AUTOCOMMIT to bypass REPEATABLE-READ staleness without
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// resorting to row locks (e.g. FOR UPDATE) or to make small out-of-band commits
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// during larger transactions. This is useful for avoiding lock contention.
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// Primary DB server attributes (should match those of the replica DB servers)
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$attributes = $this->getServerAttributes( $this->getWriterIndex() );
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if ( $attributes[Database::ATTR_DB_LEVEL_LOCKING] ) {
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// The RDBMS does not support concurrent writes (e.g. SQLite), so attempts
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// to use separate connections would just cause self-deadlocks. Note that
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// REPEATABLE-READ staleness is not an issue since DB-level locking means
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// that transactions are Strict Serializable anyway.
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$flags &= ~self::CONN_TRX_AUTOCOMMIT;
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$type = $this->getServerType( $this->getWriterIndex() );
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$this->connLogger->info( __METHOD__ . ": CONN_TRX_AUTOCOMMIT disallowed ($type)" );
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} elseif ( isset( $this->tempTablesOnlyMode[$domain] ) ) {
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// T202116: integration tests are active and queries should be all be using
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// temporary clone tables (via prefix). Such tables are not visible accross
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// different connections nor can there be REPEATABLE-READ snapshot staleness,
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// so use the same connection for everything.
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$flags &= ~self::CONN_TRX_AUTOCOMMIT;
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}
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}
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return $flags;
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}
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/**
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* @param IDatabase $conn
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* @param int $flags
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* @throws DBUnexpectedError
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*/
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private function enforceConnectionFlags( IDatabase $conn, $flags ) {
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if ( self::fieldHasBit( $flags, self::CONN_TRX_AUTOCOMMIT ) ) {
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if ( $conn->trxLevel() ) { // sanity
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throw new DBUnexpectedError(
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$conn,
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'Handle requested with CONN_TRX_AUTOCOMMIT yet it has a transaction'
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);
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}
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$conn->clearFlag( $conn::DBO_TRX ); // auto-commit mode
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}
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}
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/**
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* Get a LoadMonitor instance
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*
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* @return ILoadMonitor
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*/
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private function getLoadMonitor() {
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if ( !isset( $this->loadMonitor ) ) {
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$compat = [
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'LoadMonitor' => LoadMonitor::class,
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'LoadMonitorNull' => LoadMonitorNull::class,
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'LoadMonitorMySQL' => LoadMonitorMySQL::class,
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];
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$class = $this->loadMonitorConfig['class'];
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if ( isset( $compat[$class] ) ) {
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$class = $compat[$class];
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}
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$this->loadMonitor = new $class(
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$this, $this->srvCache, $this->wanCache, $this->loadMonitorConfig );
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$this->loadMonitor->setLogger( $this->replLogger );
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}
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return $this->loadMonitor;
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}
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/**
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* @param array $loads
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* @param string $domain Resolved DB domain
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* @param int $maxLag Restrict the maximum allowed lag to this many seconds
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* @return bool|int|string
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*/
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private function getRandomNonLagged( array $loads, string $domain, $maxLag = INF ) {
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$lags = $this->getLagTimes( $domain );
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# Unset excessively lagged servers
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foreach ( $lags as $i => $lag ) {
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if ( $i !== $this->getWriterIndex() ) {
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# How much lag this server nominally is allowed to have
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$maxServerLag = $this->servers[$i]['max lag'] ?? $this->maxLag; // default
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# Constrain that futher by $maxLag argument
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$maxServerLag = min( $maxServerLag, $maxLag );
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$srvName = $this->getServerName( $i );
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if ( $lag === false && !is_infinite( $maxServerLag ) ) {
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$this->replLogger->debug(
|
|
__METHOD__ . ": server {db_server} is not replicating?",
|
|
[ 'db_server' => $srvName ]
|
|
);
|
|
unset( $loads[$i] );
|
|
} elseif ( $lag > $maxServerLag ) {
|
|
$this->replLogger->debug(
|
|
__METHOD__ .
|
|
": server {db_server} has {lag} seconds of lag (>= {maxlag})",
|
|
[ 'db_server' => $srvName, 'lag' => $lag, 'maxlag' => $maxServerLag ]
|
|
);
|
|
unset( $loads[$i] );
|
|
}
|
|
}
|
|
}
|
|
|
|
# Find out if all the replica DBs with non-zero load are lagged
|
|
$sum = 0;
|
|
foreach ( $loads as $load ) {
|
|
$sum += $load;
|
|
}
|
|
if ( $sum == 0 ) {
|
|
# No appropriate DB servers except maybe the master and some replica DBs with zero load
|
|
# Do NOT use the master
|
|
# Instead, this function will return false, triggering read-only mode,
|
|
# and a lagged replica DB will be used instead.
|
|
return false;
|
|
}
|
|
|
|
if ( count( $loads ) == 0 ) {
|
|
return false;
|
|
}
|
|
|
|
# Return a random representative of the remainder
|
|
return ArrayUtils::pickRandom( $loads );
|
|
}
|
|
|
|
/**
|
|
* Get the server index to use for a specified server index and query group list
|
|
*
|
|
* @param int $i Specific server index or DB_PRIMARY/DB_REPLICA
|
|
* @param string[] $groups Non-empty query group list in preference order
|
|
* @param string|bool $domain
|
|
* @return int A specific server index (replica DBs are checked for connectivity)
|
|
*/
|
|
private function getConnectionIndex( $i, array $groups, $domain ) {
|
|
if ( $i === self::DB_PRIMARY ) {
|
|
$i = $this->getWriterIndex();
|
|
} elseif ( $i === self::DB_REPLICA ) {
|
|
foreach ( $groups as $group ) {
|
|
$groupIndex = $this->getReaderIndex( $group, $domain );
|
|
if ( $groupIndex !== false ) {
|
|
$i = $groupIndex; // group connection succeeded
|
|
break;
|
|
}
|
|
}
|
|
} elseif ( !isset( $this->servers[$i] ) ) {
|
|
throw new UnexpectedValueException( "Invalid server index index #$i" );
|
|
}
|
|
|
|
if ( $i === self::DB_REPLICA ) {
|
|
$this->lastError = 'Unknown error'; // set here in case of worse failure
|
|
$this->lastError = 'No working replica DB server: ' . $this->lastError;
|
|
$this->reportConnectionError();
|
|
return null; // unreachable due to exception
|
|
}
|
|
|
|
return $i;
|
|
}
|
|
|
|
public function getReaderIndex( $group = false, $domain = false ) {
|
|
$domain = $this->resolveDomainID( $domain );
|
|
$group = is_string( $group ) ? $group : self::GROUP_GENERIC;
|
|
|
|
if ( $this->getServerCount() == 1 ) {
|
|
// Skip the load balancing if there's only one server
|
|
return $this->getWriterIndex();
|
|
}
|
|
|
|
$index = $this->getExistingReaderIndex( $group );
|
|
if ( $index !== self::READER_INDEX_NONE ) {
|
|
// A reader index was already selected and "waitForPos" was handled
|
|
return $index;
|
|
}
|
|
|
|
// Use the server weight array for this load group
|
|
if ( isset( $this->groupLoads[$group] ) ) {
|
|
$loads = $this->groupLoads[$group];
|
|
} else {
|
|
$this->connLogger->info( __METHOD__ . ": no loads for group $group" );
|
|
|
|
return false;
|
|
}
|
|
|
|
// Scale the configured load ratios according to each server's load and state
|
|
$this->getLoadMonitor()->scaleLoads( $loads, $domain );
|
|
|
|
// Pick a server to use, accounting for weights, load, lag, and "waitForPos"
|
|
$this->lazyLoadReplicationPositions(); // optimizes server candidate selection
|
|
list( $i, $laggedReplicaMode ) = $this->pickReaderIndex( $loads, $domain );
|
|
if ( $i === false ) {
|
|
// DB connection unsuccessful
|
|
return false;
|
|
}
|
|
|
|
// If data seen by queries is expected to reflect the transactions committed as of
|
|
// or after a given replication position then wait for the DB to apply those changes
|
|
if ( $this->waitForPos && $i !== $this->getWriterIndex() && !$this->doWait( $i ) ) {
|
|
// Data will be outdated compared to what was expected
|
|
$laggedReplicaMode = true;
|
|
}
|
|
|
|
// Cache the reader index for future DB_REPLICA handles
|
|
$this->setExistingReaderIndex( $group, $i );
|
|
// Record whether the generic reader index is in "lagged replica DB" mode
|
|
if ( $group === self::GROUP_GENERIC && $laggedReplicaMode ) {
|
|
$this->laggedReplicaMode = true;
|
|
$this->replLogger->debug( __METHOD__ . ": setting lagged replica mode" );
|
|
}
|
|
|
|
$serverName = $this->getServerName( $i );
|
|
$this->connLogger->debug( __METHOD__ . ": using server $serverName for group '$group'" );
|
|
|
|
return $i;
|
|
}
|
|
|
|
/**
|
|
* Get the server index chosen by the load balancer for use with the given query group
|
|
*
|
|
* @param string $group Query group; use false for the generic group
|
|
* @return int Server index or LoadBalancer::READER_INDEX_NONE if none was chosen
|
|
*/
|
|
protected function getExistingReaderIndex( $group ) {
|
|
return $this->readIndexByGroup[$group] ?? self::READER_INDEX_NONE;
|
|
}
|
|
|
|
/**
|
|
* Set the server index chosen by the load balancer for use with the given query group
|
|
*
|
|
* @param string $group Query group; use false for the generic group
|
|
* @param int $index The index of a specific server
|
|
*/
|
|
private function setExistingReaderIndex( $group, $index ) {
|
|
if ( $index < 0 ) {
|
|
throw new UnexpectedValueException( "Cannot set a negative read server index" );
|
|
}
|
|
$this->readIndexByGroup[$group] = $index;
|
|
}
|
|
|
|
/**
|
|
* Pick a server that is reachable, preferably non-lagged, and return its server index
|
|
*
|
|
* This will leave the server connection open within the pool for reuse
|
|
*
|
|
* @param array $loads List of server weights
|
|
* @param string $domain Resolved DB domain
|
|
* @return array (reader index, lagged replica mode) or (false, false) on failure
|
|
*/
|
|
private function pickReaderIndex( array $loads, string $domain ) {
|
|
if ( $loads === [] ) {
|
|
throw new InvalidArgumentException( "Server configuration array is empty" );
|
|
}
|
|
|
|
/** @var int|bool $i Index of selected server */
|
|
$i = false;
|
|
/** @var bool $laggedReplicaMode Whether server is considered lagged */
|
|
$laggedReplicaMode = false;
|
|
|
|
// Quickly look through the available servers for a server that meets criteria...
|
|
$currentLoads = $loads;
|
|
while ( count( $currentLoads ) ) {
|
|
if ( $this->allowLagged || $laggedReplicaMode ) {
|
|
$i = ArrayUtils::pickRandom( $currentLoads );
|
|
} else {
|
|
$i = false;
|
|
if ( $this->waitForPos && $this->waitForPos->asOfTime() ) {
|
|
$this->replLogger->debug( __METHOD__ . ": replication positions detected" );
|
|
// "chronologyCallback" sets "waitForPos" for session consistency.
|
|
// This triggers doWait() after connect, so it's especially good to
|
|
// avoid lagged servers so as to avoid excessive delay in that method.
|
|
$ago = microtime( true ) - $this->waitForPos->asOfTime();
|
|
// Aim for <= 1 second of waiting (being too picky can backfire)
|
|
$i = $this->getRandomNonLagged( $currentLoads, $domain, $ago + 1 );
|
|
}
|
|
if ( $i === false ) {
|
|
// Any server with less lag than it's 'max lag' param is preferable
|
|
$i = $this->getRandomNonLagged( $currentLoads, $domain );
|
|
}
|
|
if ( $i === false && count( $currentLoads ) ) {
|
|
// All replica DBs lagged. Switch to read-only mode
|
|
$this->replLogger->error(
|
|
__METHOD__ . ": all replica DBs lagged. Switch to read-only mode",
|
|
[ 'db_domain' => $domain ]
|
|
);
|
|
$i = ArrayUtils::pickRandom( $currentLoads );
|
|
$laggedReplicaMode = true;
|
|
}
|
|
}
|
|
|
|
if ( $i === false ) {
|
|
// pickRandom() returned false.
|
|
// This is permanent and means the configuration or the load monitor
|
|
// wants us to return false.
|
|
$this->connLogger->debug( __METHOD__ . ": pickRandom() returned false" );
|
|
|
|
return [ false, false ];
|
|
}
|
|
|
|
$serverName = $this->getServerName( $i );
|
|
$this->connLogger->debug( __METHOD__ . ": Using reader #$i: $serverName..." );
|
|
|
|
// Get a connection to this server without triggering complementary connections
|
|
// to other servers (due to things like lag or read-only checks). We want to avoid
|
|
// the risk of overhead and recursion here.
|
|
$conn = $this->getServerConnection( $i, $domain, self::CONN_SILENCE_ERRORS );
|
|
if ( !$conn ) {
|
|
$this->connLogger->warning(
|
|
__METHOD__ . ": failed connecting to $i/{db_domain}",
|
|
[ 'db_domain' => $domain ]
|
|
);
|
|
unset( $currentLoads[$i] ); // avoid this server next iteration
|
|
$i = false;
|
|
continue;
|
|
}
|
|
|
|
// Decrement reference counter, we are finished with this connection.
|
|
// It will be incremented for the caller later.
|
|
if ( !$this->localDomain->equals( $domain ) ) {
|
|
$this->reuseConnection( $conn );
|
|
}
|
|
|
|
// Return this server
|
|
break;
|
|
}
|
|
|
|
// If all servers were down, quit now
|
|
if ( $currentLoads === [] ) {
|
|
$this->connLogger->error(
|
|
__METHOD__ . ": all servers down",
|
|
[ 'db_domain' => $domain ]
|
|
);
|
|
}
|
|
|
|
return [ $i, $laggedReplicaMode ];
|
|
}
|
|
|
|
public function waitFor( $pos ) {
|
|
$oldPos = $this->waitForPos;
|
|
try {
|
|
$this->waitForPos = $pos;
|
|
|
|
$genericIndex = $this->getExistingReaderIndex( self::GROUP_GENERIC );
|
|
// If a generic reader connection was already established, then wait now.
|
|
// Otherwise, wait until a connection is established in getReaderIndex().
|
|
if ( $genericIndex > $this->getWriterIndex() && !$this->doWait( $genericIndex ) ) {
|
|
$this->laggedReplicaMode = true;
|
|
$this->replLogger->debug( __METHOD__ . ": setting lagged replica mode" );
|
|
}
|
|
} finally {
|
|
// Restore the older position if it was higher since this is used for lag-protection
|
|
$this->setWaitForPositionIfHigher( $oldPos );
|
|
}
|
|
}
|
|
|
|
public function waitForOne( $pos, $timeout = null ) {
|
|
$oldPos = $this->waitForPos;
|
|
try {
|
|
$this->waitForPos = $pos;
|
|
|
|
$genericIndex = $this->getExistingReaderIndex( self::GROUP_GENERIC );
|
|
// If a generic reader connection was already established to a replica server,
|
|
// then use that server. Otherwise, just pick a random replica server.
|
|
if ( $genericIndex > $this->getWriterIndex() ) {
|
|
$i = $genericIndex;
|
|
} else {
|
|
$readLoads = $this->groupLoads[self::GROUP_GENERIC];
|
|
unset( $readLoads[$this->getWriterIndex()] ); // replica DBs only
|
|
$readLoads = array_filter( $readLoads ); // with non-zero load
|
|
$i = ArrayUtils::pickRandom( $readLoads );
|
|
}
|
|
|
|
if ( $i !== false ) {
|
|
$ok = $this->doWait( $i, $timeout );
|
|
} else {
|
|
$ok = true; // no applicable loads
|
|
}
|
|
|
|
return $ok;
|
|
} finally {
|
|
// Restore the old position; this is used for throttling, not lag-protection
|
|
$this->waitForPos = $oldPos;
|
|
}
|
|
}
|
|
|
|
public function waitForAll( $pos, $timeout = null ) {
|
|
$timeout = $timeout ?: $this->waitTimeout;
|
|
|
|
$oldPos = $this->waitForPos;
|
|
try {
|
|
$this->waitForPos = $pos;
|
|
|
|
$ok = true;
|
|
foreach ( $this->getStreamingReplicaIndexes() as $i ) {
|
|
if ( $this->serverHasLoadInAnyGroup( $i ) ) {
|
|
$start = microtime( true );
|
|
$ok = $this->doWait( $i, $timeout ) && $ok;
|
|
$timeout -= intval( microtime( true ) - $start );
|
|
if ( $timeout <= 0 ) {
|
|
break; // timeout reached
|
|
}
|
|
}
|
|
}
|
|
|
|
return $ok;
|
|
} finally {
|
|
// Restore the old position; this is used for throttling, not lag-protection
|
|
$this->waitForPos = $oldPos;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @param int $i Specific server index
|
|
* @return bool
|
|
*/
|
|
private function serverHasLoadInAnyGroup( $i ) {
|
|
foreach ( $this->groupLoads as $loadsByIndex ) {
|
|
if ( ( $loadsByIndex[$i] ?? 0 ) > 0 ) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* @param DBPrimaryPos|bool $pos
|
|
*/
|
|
private function setWaitForPositionIfHigher( $pos ) {
|
|
if ( !$pos ) {
|
|
return;
|
|
}
|
|
|
|
if ( !$this->waitForPos || $pos->hasReached( $this->waitForPos ) ) {
|
|
$this->waitForPos = $pos;
|
|
}
|
|
}
|
|
|
|
public function getAnyOpenConnection( $i, $flags = 0 ) {
|
|
$i = ( $i === self::DB_PRIMARY ) ? $this->getWriterIndex() : $i;
|
|
// Connection handles required to be in auto-commit mode use a separate connection
|
|
// pool since the main pool is effected by implicit and explicit transaction rounds
|
|
$autoCommitOnly = self::fieldHasBit( $flags, self::CONN_TRX_AUTOCOMMIT );
|
|
|
|
$conn = false;
|
|
foreach ( $this->conns as $type => $connsByServer ) {
|
|
if ( $i === self::DB_REPLICA ) {
|
|
// Consider all existing connections to any server
|
|
$applicableConnsByServer = $connsByServer;
|
|
} else {
|
|
// Consider all existing connections to a specific server
|
|
$applicableConnsByServer = isset( $connsByServer[$i] )
|
|
? [ $i => $connsByServer[$i] ]
|
|
: [];
|
|
}
|
|
|
|
$conn = $this->pickAnyOpenConnection( $applicableConnsByServer, $autoCommitOnly );
|
|
if ( $conn ) {
|
|
$this->connLogger->debug( __METHOD__ . ": found '$type' connection to #$i." );
|
|
break;
|
|
}
|
|
}
|
|
|
|
if ( $conn ) {
|
|
$this->enforceConnectionFlags( $conn, $flags );
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
|
|
/**
|
|
* @param Database[][] $connsByServer Map of (server index => array of DB handles)
|
|
* @param bool $autoCommitOnly Whether to only look for auto-commit connections
|
|
* @return IDatabase|false An appropriate open connection or false if none found
|
|
*/
|
|
private function pickAnyOpenConnection( array $connsByServer, $autoCommitOnly ) {
|
|
foreach ( $connsByServer as $i => $conns ) {
|
|
foreach ( $conns as $conn ) {
|
|
if ( !$conn->isOpen() ) {
|
|
$this->connLogger->warning(
|
|
__METHOD__ .
|
|
": pooled DB handle for {db_server} (#$i) has no open connection.",
|
|
$this->getConnLogContext( $conn )
|
|
);
|
|
|
|
continue; // some sort of error occurred?
|
|
}
|
|
|
|
if ( $autoCommitOnly ) {
|
|
// Only accept CONN_TRX_AUTOCOMMIT connections
|
|
if ( !$conn->getLBInfo( self::INFO_AUTOCOMMIT_ONLY ) ) {
|
|
// Connection is aware of transaction rounds
|
|
continue;
|
|
}
|
|
|
|
if ( $conn->trxLevel() ) {
|
|
// Some sort of bug left a transaction open
|
|
$this->connLogger->warning(
|
|
__METHOD__ .
|
|
": pooled DB handle for {db_server} (#$i) has a pending transaction.",
|
|
$this->getConnLogContext( $conn )
|
|
);
|
|
|
|
continue;
|
|
}
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Wait for a given replica DB to catch up to the master pos stored in "waitForPos"
|
|
*
|
|
* @param int $index Specific server index
|
|
* @param int|null $timeout Max seconds to wait; default is "waitTimeout"
|
|
* @return bool
|
|
*/
|
|
private function doWait( $index, $timeout = null ) {
|
|
$timeout = max( 1, intval( $timeout ?: $this->waitTimeout ) );
|
|
|
|
// Check if we already know that the DB has reached this point
|
|
$srvName = $this->getServerName( $index );
|
|
$key = $this->srvCache->makeGlobalKey( __CLASS__, 'last-known-pos', $srvName, 'v1' );
|
|
/** @var DBPrimaryPos $knownReachedPos */
|
|
$knownReachedPos = $this->srvCache->get( $key );
|
|
if (
|
|
$knownReachedPos instanceof DBPrimaryPos &&
|
|
$knownReachedPos->hasReached( $this->waitForPos )
|
|
) {
|
|
$this->replLogger->debug(
|
|
__METHOD__ .
|
|
": replica DB {db_server} known to be caught up (pos >= $knownReachedPos).",
|
|
[ 'db_server' => $srvName ]
|
|
);
|
|
|
|
return true;
|
|
}
|
|
|
|
$close = false; // close the connection afterwards
|
|
$flags = self::CONN_SILENCE_ERRORS;
|
|
// Check if there is an existing connection that can be used
|
|
$conn = $this->getAnyOpenConnection( $index, $flags );
|
|
if ( !$conn ) {
|
|
// Get a connection to this server without triggering complementary connections
|
|
// to other servers (due to things like lag or read-only checks). We want to avoid
|
|
// the risk of overhead and recursion here.
|
|
$conn = $this->getServerConnection( $index, self::DOMAIN_ANY, $flags );
|
|
if ( !$conn ) {
|
|
$this->replLogger->warning(
|
|
__METHOD__ . ': failed to connect to {db_server}',
|
|
[ 'db_server' => $srvName ]
|
|
);
|
|
|
|
return false;
|
|
}
|
|
// Avoid connection spam in waitForAll() when connections
|
|
// are made just for the sake of doing this lag check.
|
|
$close = true;
|
|
}
|
|
|
|
$this->replLogger->info(
|
|
__METHOD__ .
|
|
': waiting for replica DB {db_server} to catch up...',
|
|
$this->getConnLogContext( $conn )
|
|
);
|
|
|
|
$result = $conn->masterPosWait( $this->waitForPos, $timeout );
|
|
|
|
$ok = ( $result !== null && $result != -1 );
|
|
if ( $ok ) {
|
|
// Remember that the DB reached this point
|
|
$this->srvCache->set( $key, $this->waitForPos, BagOStuff::TTL_DAY );
|
|
}
|
|
|
|
if ( $close ) {
|
|
$this->closeConnection( $conn );
|
|
}
|
|
|
|
return $ok;
|
|
}
|
|
|
|
public function getConnection( $i, $groups = [], $domain = false, $flags = 0 ) {
|
|
$domain = $this->resolveDomainID( $domain );
|
|
$groups = $this->resolveGroups( $groups, $i );
|
|
$flags = $this->sanitizeConnectionFlags( $flags, $i, $domain );
|
|
// If given DB_PRIMARY/DB_REPLICA, resolve it to a specific server index. Resolving
|
|
// DB_REPLICA might trigger getServerConnection() calls due to the getReaderIndex()
|
|
// connectivity checks or LoadMonitor::scaleLoads() server state cache regeneration.
|
|
// The use of getServerConnection() instead of getConnection() avoids infinite loops.
|
|
$serverIndex = $this->getConnectionIndex( $i, $groups, $domain );
|
|
// Get an open connection to that server (might trigger a new connection)
|
|
$conn = $this->getServerConnection( $serverIndex, $domain, $flags );
|
|
// Set primary DB handles as read-only if there is high replication lag
|
|
if (
|
|
$conn &&
|
|
$serverIndex === $this->getWriterIndex() &&
|
|
$this->getLaggedReplicaMode( $domain ) &&
|
|
!is_string( $conn->getLBInfo( $conn::LB_READ_ONLY_REASON ) )
|
|
) {
|
|
$genericIndex = $this->getExistingReaderIndex( self::GROUP_GENERIC );
|
|
$reason = ( $genericIndex !== self::READER_INDEX_NONE )
|
|
? 'The database is read-only until replication lag decreases.'
|
|
: 'The database is read-only until replica database servers becomes reachable.';
|
|
$conn->setLBInfo( $conn::LB_READ_ONLY_REASON, $reason );
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
|
|
public function getServerConnection( $i, $domain, $flags = 0 ) {
|
|
// Number of connections made before getting the server index and handle
|
|
$priorConnectionsMade = $this->connectionCounter;
|
|
// Get an open connection to this server (might trigger a new connection)
|
|
$conn = $this->localDomain->equals( $domain )
|
|
? $this->getLocalConnection( $i, $flags )
|
|
: $this->getForeignConnection( $i, $domain, $flags );
|
|
// Throw an error or otherwise bail out if the connection attempt failed
|
|
if ( !( $conn instanceof IDatabase ) ) {
|
|
if ( !self::fieldHasBit( $flags, self::CONN_SILENCE_ERRORS ) ) {
|
|
$this->reportConnectionError();
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
// Profile any new connections caused by this method
|
|
if ( $this->connectionCounter > $priorConnectionsMade ) {
|
|
$this->trxProfiler->recordConnection(
|
|
$conn->getServerName(),
|
|
$conn->getDBname(),
|
|
self::fieldHasBit( $flags, self::CONN_INTENT_WRITABLE )
|
|
);
|
|
}
|
|
|
|
if ( !$conn->isOpen() ) {
|
|
$this->errorConnection = $conn;
|
|
// Connection was made but later unrecoverably lost for some reason.
|
|
// Do not return a handle that will just throw exceptions on use, but
|
|
// let the calling code, e.g. getReaderIndex(), try another server.
|
|
// FIXME: report an error here unless CONN_SILENCE_ERRORS was set
|
|
return false;
|
|
}
|
|
|
|
// Make sure that flags like CONN_TRX_AUTOCOMMIT are respected by this handle
|
|
$this->enforceConnectionFlags( $conn, $flags );
|
|
// Set primary DB handles as read-only if the load balancer is configured as read-only
|
|
// or the primary database server is running in server-side read-only mode. Note that
|
|
// replica DB handles are always read-only via Database::assertIsWritableMaster().
|
|
// Read-only mode due to replication lag is *avoided* here to avoid recursion.
|
|
if ( $i === $this->getWriterIndex() ) {
|
|
if ( $this->readOnlyReason !== false ) {
|
|
$readOnlyReason = $this->readOnlyReason;
|
|
} elseif ( $this->isMasterConnectionReadOnly( $conn, $flags ) ) {
|
|
$readOnlyReason = 'The primary database server is running in read-only mode.';
|
|
} else {
|
|
$readOnlyReason = false;
|
|
}
|
|
$conn->setLBInfo( $conn::LB_READ_ONLY_REASON, $readOnlyReason );
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
|
|
public function reuseConnection( IDatabase $conn ) {
|
|
$serverIndex = $conn->getLBInfo( self::INFO_SERVER_INDEX );
|
|
$refCount = $conn->getLBInfo( self::INFO_FOREIGN_REF_COUNT );
|
|
if ( $serverIndex === null || $refCount === null ) {
|
|
return; // non-foreign connection; no domain-use tracking to update
|
|
} elseif ( $conn instanceof DBConnRef ) {
|
|
// DBConnRef already handles calling reuseConnection() and only passes the live
|
|
// Database instance to this method. Any caller passing in a DBConnRef is broken.
|
|
$this->connLogger->error(
|
|
__METHOD__ . ": got DBConnRef instance",
|
|
[ 'db_domain' => $conn->getDomainID(), 'exception' => new RuntimeException() ]
|
|
);
|
|
|
|
return;
|
|
}
|
|
|
|
if ( $this->disabled ) {
|
|
return; // DBConnRef handle probably survived longer than the LoadBalancer
|
|
}
|
|
|
|
if ( $conn->getLBInfo( self::INFO_AUTOCOMMIT_ONLY ) ) {
|
|
$connFreeKey = self::KEY_FOREIGN_FREE_NOROUND;
|
|
$connInUseKey = self::KEY_FOREIGN_INUSE_NOROUND;
|
|
} else {
|
|
$connFreeKey = self::KEY_FOREIGN_FREE;
|
|
$connInUseKey = self::KEY_FOREIGN_INUSE;
|
|
}
|
|
|
|
$domain = $conn->getDomainID();
|
|
$existingDomainConn = $this->conns[$connInUseKey][$serverIndex][$domain] ?? null;
|
|
if ( !$existingDomainConn ) {
|
|
throw new InvalidArgumentException(
|
|
"Connection $serverIndex/$domain not found; it may have already been freed" );
|
|
} elseif ( $existingDomainConn !== $conn ) {
|
|
throw new InvalidArgumentException(
|
|
"Connection $serverIndex/$domain mismatched; it may have already been freed" );
|
|
}
|
|
|
|
$existingDomainConn->setLBInfo( self::INFO_FOREIGN_REF_COUNT, --$refCount );
|
|
if ( $refCount <= 0 ) {
|
|
$this->conns[$connFreeKey][$serverIndex][$domain] = $existingDomainConn;
|
|
unset( $this->conns[$connInUseKey][$serverIndex][$domain] );
|
|
if ( !$this->conns[$connInUseKey][$serverIndex] ) {
|
|
unset( $this->conns[$connInUseKey][$serverIndex] ); // clean up
|
|
}
|
|
$this->connLogger->debug( __METHOD__ . ": freed connection $serverIndex/$domain" );
|
|
} else {
|
|
$this->connLogger->debug( __METHOD__ .
|
|
": reference count for $serverIndex/$domain reduced to $refCount" );
|
|
}
|
|
}
|
|
|
|
public function getConnectionRef( $i, $groups = [], $domain = false, $flags = 0 ) {
|
|
if ( self::fieldHasBit( $flags, self::CONN_SILENCE_ERRORS ) ) {
|
|
throw new UnexpectedValueException(
|
|
__METHOD__ . ' CONN_SILENCE_ERRORS is not supported'
|
|
);
|
|
}
|
|
|
|
$domain = $this->resolveDomainID( $domain );
|
|
$role = $this->getRoleFromIndex( $i );
|
|
$conn = $this->getConnection( $i, $groups, $domain, $flags );
|
|
|
|
return new DBConnRef( $this, $conn, $role );
|
|
}
|
|
|
|
public function getLazyConnectionRef( $i, $groups = [], $domain = false, $flags = 0 ): DBConnRef {
|
|
if ( self::fieldHasBit( $flags, self::CONN_SILENCE_ERRORS ) ) {
|
|
throw new UnexpectedValueException(
|
|
__METHOD__ . ' got CONN_SILENCE_ERRORS; connection is already deferred'
|
|
);
|
|
}
|
|
|
|
$domain = $this->resolveDomainID( $domain );
|
|
$role = $this->getRoleFromIndex( $i );
|
|
|
|
return new DBConnRef( $this, [ $i, $groups, $domain, $flags ], $role );
|
|
}
|
|
|
|
public function getMaintenanceConnectionRef(
|
|
$i,
|
|
$groups = [],
|
|
$domain = false,
|
|
$flags = 0
|
|
): MaintainableDBConnRef {
|
|
if ( self::fieldHasBit( $flags, self::CONN_SILENCE_ERRORS ) ) {
|
|
throw new UnexpectedValueException(
|
|
__METHOD__ . ' CONN_SILENCE_ERRORS is not supported'
|
|
);
|
|
}
|
|
|
|
$domain = $this->resolveDomainID( $domain );
|
|
$role = $this->getRoleFromIndex( $i );
|
|
$conn = $this->getConnection( $i, $groups, $domain, $flags );
|
|
|
|
return new MaintainableDBConnRef( $this, $conn, $role );
|
|
}
|
|
|
|
/**
|
|
* @param int $i Server index or DB_PRIMARY/DB_REPLICA
|
|
* @return int One of DB_PRIMARY/DB_REPLICA
|
|
*/
|
|
private function getRoleFromIndex( $i ) {
|
|
return ( $i === self::DB_PRIMARY || $i === $this->getWriterIndex() )
|
|
? self::DB_PRIMARY
|
|
: self::DB_REPLICA;
|
|
}
|
|
|
|
/**
|
|
* @param int $i
|
|
* @param string|bool $domain
|
|
* @param int $flags
|
|
* @return Database|bool Live database handle or false on failure
|
|
* @deprecated Since 1.34 Use getConnection() instead
|
|
*/
|
|
public function openConnection( $i, $domain = false, $flags = 0 ) {
|
|
return $this->getConnection( $i, [], $domain, $flags | self::CONN_SILENCE_ERRORS );
|
|
}
|
|
|
|
/**
|
|
* Open a connection to a local DB, or return one if it is already open.
|
|
*
|
|
* 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.
|
|
*
|
|
* @param int $i Specific server index
|
|
* @param int $flags Class CONN_* constant bitfield
|
|
* @return Database
|
|
* @throws InvalidArgumentException When the server index is invalid
|
|
* @throws UnexpectedValueException When the DB domain of the connection is corrupted
|
|
*/
|
|
private function getLocalConnection( $i, $flags = 0 ) {
|
|
$autoCommit = self::fieldHasBit( $flags, self::CONN_TRX_AUTOCOMMIT );
|
|
// Connection handles required to be in auto-commit mode use a separate connection
|
|
// pool since the main pool is effected by implicit and explicit transaction rounds
|
|
$connKey = $autoCommit ? self::KEY_LOCAL_NOROUND : self::KEY_LOCAL;
|
|
|
|
if ( isset( $this->conns[$connKey][$i][self::KEY_LOCAL_DOMAIN] ) ) {
|
|
$conn = $this->conns[$connKey][$i][self::KEY_LOCAL_DOMAIN];
|
|
$this->connLogger->debug( __METHOD__ . ": reused a connection for $connKey/$i" );
|
|
} else {
|
|
$conn = $this->reallyOpenConnection(
|
|
$i,
|
|
$this->localDomain,
|
|
[ self::INFO_AUTOCOMMIT_ONLY => $autoCommit ]
|
|
);
|
|
if ( $conn->isOpen() ) {
|
|
$this->connLogger->debug( __METHOD__ . ": opened new connection for $connKey/$i" );
|
|
$this->conns[$connKey][$i][self::KEY_LOCAL_DOMAIN] = $conn;
|
|
} else {
|
|
$this->connLogger->warning( __METHOD__ . ": connection error for $connKey/$i" );
|
|
$this->errorConnection = $conn;
|
|
$conn = false;
|
|
}
|
|
}
|
|
|
|
// Sanity check to make sure that the right domain is selected
|
|
if (
|
|
$conn instanceof IDatabase &&
|
|
!$this->localDomain->isCompatible( $conn->getDomainID() )
|
|
) {
|
|
throw new UnexpectedValueException(
|
|
"Got connection to '{$conn->getDomainID()}', " .
|
|
"but expected local domain ('{$this->localDomain}')"
|
|
);
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* @param int $i Specific server index
|
|
* @param string $domain Domain ID to open
|
|
* @param int $flags Class CONN_* constant bitfield
|
|
* @return Database|bool Returns false on connection error
|
|
* @throws DBError When database selection fails
|
|
* @throws InvalidArgumentException When the server index is invalid
|
|
* @throws UnexpectedValueException When the DB domain of the connection is corrupted
|
|
*/
|
|
private function getForeignConnection( $i, $domain, $flags = 0 ) {
|
|
$domainInstance = DatabaseDomain::newFromId( $domain );
|
|
$autoCommit = self::fieldHasBit( $flags, self::CONN_TRX_AUTOCOMMIT );
|
|
// Connection handles required to be in auto-commit mode use a separate connection
|
|
// pool since the main pool is effected by implicit and explicit transaction rounds
|
|
if ( $autoCommit ) {
|
|
$connFreeKey = self::KEY_FOREIGN_FREE_NOROUND;
|
|
$connInUseKey = self::KEY_FOREIGN_INUSE_NOROUND;
|
|
} else {
|
|
$connFreeKey = self::KEY_FOREIGN_FREE;
|
|
$connInUseKey = self::KEY_FOREIGN_INUSE;
|
|
}
|
|
|
|
/** @var Database $conn */
|
|
$conn = null;
|
|
|
|
if ( isset( $this->conns[$connInUseKey][$i][$domain] ) ) {
|
|
// Reuse an in-use connection for the same domain
|
|
$conn = $this->conns[$connInUseKey][$i][$domain];
|
|
$this->connLogger->debug( __METHOD__ . ": reusing connection $connInUseKey/$i/$domain" );
|
|
} elseif ( isset( $this->conns[$connFreeKey][$i][$domain] ) ) {
|
|
// Reuse a free connection for the same domain
|
|
$conn = $this->conns[$connFreeKey][$i][$domain];
|
|
unset( $this->conns[$connFreeKey][$i][$domain] );
|
|
$this->conns[$connInUseKey][$i][$domain] = $conn;
|
|
$this->connLogger->debug( __METHOD__ . ": reusing free connection $connInUseKey/$i/$domain" );
|
|
} elseif ( !empty( $this->conns[$connFreeKey][$i] ) ) {
|
|
// Reuse a free connection from another domain if possible
|
|
foreach ( $this->conns[$connFreeKey][$i] as $oldDomain => $oldConn ) {
|
|
if ( $domainInstance->getDatabase() !== null ) {
|
|
// Check if changing the database will require a new connection.
|
|
// In that case, leave the connection handle alone and keep looking.
|
|
// This prevents connections from being closed mid-transaction and can
|
|
// also avoid overhead if the same database will later be requested.
|
|
if (
|
|
$oldConn->databasesAreIndependent() &&
|
|
$oldConn->getDBname() !== $domainInstance->getDatabase()
|
|
) {
|
|
continue;
|
|
}
|
|
// Select the new database, schema, and prefix
|
|
$conn = $oldConn;
|
|
$conn->selectDomain( $domainInstance );
|
|
} else {
|
|
// Stay on the current database, but update the schema/prefix
|
|
$conn = $oldConn;
|
|
$conn->dbSchema( $domainInstance->getSchema() );
|
|
$conn->tablePrefix( $domainInstance->getTablePrefix() );
|
|
}
|
|
unset( $this->conns[$connFreeKey][$i][$oldDomain] );
|
|
// Note that if $domain is an empty string, getDomainID() might not match it
|
|
$this->conns[$connInUseKey][$i][$conn->getDomainID()] = $conn;
|
|
$this->connLogger->debug( __METHOD__ .
|
|
": reusing free connection from $oldDomain for $domain" );
|
|
break;
|
|
}
|
|
}
|
|
|
|
if ( !$conn ) {
|
|
$conn = $this->reallyOpenConnection(
|
|
$i,
|
|
$domainInstance,
|
|
[
|
|
self::INFO_AUTOCOMMIT_ONLY => $autoCommit,
|
|
self::INFO_FORIEGN => true,
|
|
self::INFO_FOREIGN_REF_COUNT => 0
|
|
]
|
|
);
|
|
if ( $conn->isOpen() ) {
|
|
// Note that if $domain is an empty string, getDomainID() might not match it
|
|
$this->conns[$connInUseKey][$i][$conn->getDomainID()] = $conn;
|
|
$this->connLogger->debug( __METHOD__ . ": opened new connection for $connInUseKey/$i/$domain" );
|
|
} else {
|
|
$this->connLogger->warning(
|
|
__METHOD__ . ": connection error for $connInUseKey/$i/{db_domain}",
|
|
[ 'db_domain' => $domain ]
|
|
);
|
|
$this->errorConnection = $conn;
|
|
$conn = false;
|
|
}
|
|
}
|
|
|
|
if ( $conn instanceof IDatabase ) {
|
|
// Sanity check to make sure that the right domain is selected
|
|
if ( !$domainInstance->isCompatible( $conn->getDomainID() ) ) {
|
|
throw new UnexpectedValueException(
|
|
"Got connection to '{$conn->getDomainID()}', but expected '$domain'" );
|
|
}
|
|
// Increment reference count
|
|
$refCount = $conn->getLBInfo( self::INFO_FOREIGN_REF_COUNT );
|
|
$conn->setLBInfo( self::INFO_FOREIGN_REF_COUNT, $refCount + 1 );
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
|
|
public function getServerAttributes( $i ) {
|
|
return Database::attributesFromType(
|
|
$this->getServerType( $i ),
|
|
$this->servers[$i]['driver'] ?? null
|
|
);
|
|
}
|
|
|
|
/**
|
|
* Test if the specified index represents an open connection
|
|
*
|
|
* @param int $index Server index
|
|
* @return bool
|
|
*/
|
|
private function isOpen( $index ) {
|
|
return (bool)$this->getAnyOpenConnection( $index );
|
|
}
|
|
|
|
/**
|
|
* Open a new network connection to a server (uncached)
|
|
*
|
|
* Returns a Database object whether or not the connection was successful.
|
|
*
|
|
* @param int $i Specific server index
|
|
* @param DatabaseDomain $domain Domain the connection is for, possibly unspecified
|
|
* @param array $lbInfo Additional information for setLBInfo()
|
|
* @return IDatabase
|
|
* @throws DBAccessError
|
|
* @throws InvalidArgumentException
|
|
*/
|
|
protected function reallyOpenConnection( $i, DatabaseDomain $domain, array $lbInfo ) {
|
|
if ( $this->disabled ) {
|
|
throw new DBAccessError();
|
|
}
|
|
|
|
$server = $this->getServerInfoStrict( $i );
|
|
|
|
$conn = Database::factory(
|
|
$server['type'],
|
|
array_merge( $server, [
|
|
// Basic replication role information
|
|
'topologyRole' => $this->getTopologyRole( $i, $server ),
|
|
'topologicalMaster' => $this->getMasterServerName(),
|
|
// Use the database specified in $domain (null means "none or entrypoint DB");
|
|
// fallback to the $server default if the RDBMs is an embedded library using a
|
|
// file on disk since there would be nothing to access to without a DB/file name.
|
|
'dbname' => $this->getServerAttributes( $i )[Database::ATTR_DB_IS_FILE]
|
|
? ( $domain->getDatabase() ?? $server['dbname'] ?? null )
|
|
: $domain->getDatabase(),
|
|
// Override the $server default schema with that of $domain if specified
|
|
'schema' => $domain->getSchema() ?? $server['schema'] ?? null,
|
|
// Use the table prefix specified in $domain
|
|
'tablePrefix' => $domain->getTablePrefix(),
|
|
// Participate in transaction rounds if $server does not specify otherwise
|
|
'flags' => $this->initConnFlags( $server['flags'] ?? IDatabase::DBO_DEFAULT ),
|
|
// Inject the PHP execution mode and the agent string
|
|
'cliMode' => $this->cliMode,
|
|
'agent' => $this->agent,
|
|
'ownerId' => $this->id,
|
|
// Inject object and callback dependencies
|
|
'lazyMasterHandle' => $this->getLazyConnectionRef(
|
|
self::DB_PRIMARY,
|
|
[],
|
|
$domain->getId()
|
|
),
|
|
'srvCache' => $this->srvCache,
|
|
'connLogger' => $this->connLogger,
|
|
'queryLogger' => $this->queryLogger,
|
|
'replLogger' => $this->replLogger,
|
|
'errorLogger' => $this->errorLogger,
|
|
'deprecationLogger' => $this->deprecationLogger,
|
|
'profiler' => $this->profiler,
|
|
'trxProfiler' => $this->trxProfiler,
|
|
'criticalSectionProvider' => $this->csProvider
|
|
] ),
|
|
Database::NEW_UNCONNECTED
|
|
);
|
|
// Attach load balancer information to the handle
|
|
$conn->setLBInfo( [ self::INFO_SERVER_INDEX => $i ] + $lbInfo );
|
|
// Set alternative table/index names before any queries can be issued
|
|
$conn->setTableAliases( $this->tableAliases );
|
|
$conn->setIndexAliases( $this->indexAliases );
|
|
// Account for any active transaction round and listeners
|
|
if ( $i === $this->getWriterIndex() ) {
|
|
if ( $this->trxRoundId !== false ) {
|
|
$this->applyTransactionRoundFlags( $conn );
|
|
}
|
|
foreach ( $this->trxRecurringCallbacks as $name => $callback ) {
|
|
$conn->setTransactionListener( $name, $callback );
|
|
}
|
|
}
|
|
|
|
// Make the connection handle live
|
|
try {
|
|
$conn->initConnection();
|
|
++$this->connectionCounter;
|
|
} catch ( DBConnectionError $e ) {
|
|
// ignore; let the DB handle the logging
|
|
}
|
|
|
|
// Try to maintain session consistency for clients that trigger write transactions
|
|
// in a request or script and then return soon after in another request or script.
|
|
// This requires cooperation with ChronologyProtector and the application wiring.
|
|
if ( $conn->isOpen() ) {
|
|
$this->lazyLoadReplicationPositions();
|
|
}
|
|
|
|
// Log when many connection are made during a single request/script
|
|
$count = $this->getCurrentConnectionCount();
|
|
if ( $count >= self::CONN_HELD_WARN_THRESHOLD ) {
|
|
$this->perfLogger->warning(
|
|
__METHOD__ . ": {connections}+ connections made (master={masterdb})",
|
|
$this->getConnLogContext(
|
|
$conn,
|
|
[
|
|
'connections' => $count,
|
|
'masterdb' => $this->getMasterServerName(),
|
|
'db_domain' => $domain->getId()
|
|
]
|
|
)
|
|
);
|
|
}
|
|
|
|
return $conn;
|
|
}
|
|
|
|
/**
|
|
* @param int $i Specific server index
|
|
* @param array $server Server config map
|
|
* @return string IDatabase::ROLE_* constant
|
|
*/
|
|
private function getTopologyRole( $i, array $server ) {
|
|
if ( !empty( $server['is static'] ) ) {
|
|
return IDatabase::ROLE_STATIC_CLONE;
|
|
}
|
|
|
|
return ( $i === $this->getWriterIndex() )
|
|
? IDatabase::ROLE_STREAMING_MASTER
|
|
: IDatabase::ROLE_STREAMING_REPLICA;
|
|
}
|
|
|
|
/**
|
|
* @see IDatabase::DBO_DEFAULT
|
|
* @param int $flags Bit field of IDatabase::DBO_* constants from configuration
|
|
* @return int Bit field of IDatabase::DBO_* constants to use with Database::factory()
|
|
*/
|
|
private function initConnFlags( $flags ) {
|
|
if ( self::fieldHasBit( $flags, IDatabase::DBO_DEFAULT ) ) {
|
|
if ( $this->cliMode ) {
|
|
$flags &= ~IDatabase::DBO_TRX;
|
|
} else {
|
|
$flags |= IDatabase::DBO_TRX;
|
|
}
|
|
}
|
|
|
|
return $flags;
|
|
}
|
|
|
|
/**
|
|
* Make sure that any "waitForPos" positions are loaded and available to doWait()
|
|
*/
|
|
private function lazyLoadReplicationPositions() {
|
|
if ( !$this->chronologyCallbackTriggered && $this->chronologyCallback ) {
|
|
$this->chronologyCallbackTriggered = true;
|
|
( $this->chronologyCallback )( $this ); // generally calls waitFor()
|
|
$this->connLogger->debug( __METHOD__ . ': executed chronology callback.' );
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @throws DBConnectionError
|
|
*/
|
|
private function reportConnectionError() {
|
|
$conn = $this->errorConnection; // the connection which caused the error
|
|
$context = [
|
|
'method' => __METHOD__,
|
|
'last_error' => $this->lastError,
|
|
];
|
|
|
|
if ( $conn instanceof IDatabase ) {
|
|
$srvName = $conn->getServerName();
|
|
$this->connLogger->warning(
|
|
__METHOD__ . ": connection error: {last_error} ({db_server})",
|
|
$this->getConnLogContext( $conn, $context )
|
|
);
|
|
$error = $conn->lastError() ?: $this->lastError;
|
|
throw new DBConnectionError( $conn, "{$error} ($srvName)" );
|
|
} else {
|
|
// No last connection, probably due to all servers being too busy
|
|
$this->connLogger->error(
|
|
__METHOD__ .
|
|
": LB failure with no last connection. Connection error: {last_error}",
|
|
$context
|
|
);
|
|
|
|
// If all servers were busy, "lastError" will contain something sensible
|
|
throw new DBConnectionError( null, $this->lastError );
|
|
}
|
|
}
|
|
|
|
public function getWriterIndex() {
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Returns true if the specified index is a valid server index
|
|
*
|
|
* @param int $i
|
|
* @return bool
|
|
* @deprecated Since 1.34
|
|
*/
|
|
public function haveIndex( $i ) {
|
|
return array_key_exists( $i, $this->servers );
|
|
}
|
|
|
|
/**
|
|
* Returns true if the specified index is valid and has non-zero load
|
|
*
|
|
* @param int $i
|
|
* @return bool
|
|
* @deprecated Since 1.34
|
|
*/
|
|
public function isNonZeroLoad( $i ) {
|
|
return ( isset( $this->servers[$i] ) && $this->groupLoads[self::GROUP_GENERIC][$i] > 0 );
|
|
}
|
|
|
|
public function getServerCount() {
|
|
return count( $this->servers );
|
|
}
|
|
|
|
public function hasReplicaServers() {
|
|
return ( $this->getServerCount() > 1 );
|
|
}
|
|
|
|
/**
|
|
* @return int[] List of replica server indexes
|
|
*/
|
|
private function getStreamingReplicaIndexes() {
|
|
$indexes = [];
|
|
foreach ( $this->servers as $i => $server ) {
|
|
if ( $i !== $this->getWriterIndex() && empty( $server['is static'] ) ) {
|
|
$indexes[] = $i;
|
|
}
|
|
}
|
|
|
|
return $indexes;
|
|
}
|
|
|
|
public function hasStreamingReplicaServers() {
|
|
return (bool)$this->getStreamingReplicaIndexes();
|
|
}
|
|
|
|
public function getServerName( $i ) {
|
|
$name = $this->servers[$i]['serverName'] ?? ( $this->servers[$i]['host'] ?? '' );
|
|
|
|
return ( $name != '' ) ? $name : 'localhost';
|
|
}
|
|
|
|
public function getServerInfo( $i ) {
|
|
return $this->servers[$i] ?? false;
|
|
}
|
|
|
|
public function getServerType( $i ) {
|
|
return $this->servers[$i]['type'] ?? 'unknown';
|
|
}
|
|
|
|
public function getPrimaryPos() {
|
|
$index = $this->getWriterIndex();
|
|
|
|
$conn = $this->getAnyOpenConnection( $index );
|
|
if ( $conn ) {
|
|
return $conn->getPrimaryPos();
|
|
}
|
|
|
|
$conn = $this->getConnection( $index, self::CONN_SILENCE_ERRORS );
|
|
if ( !$conn ) {
|
|
$this->reportConnectionError();
|
|
return null; // unreachable due to exception
|
|
}
|
|
|
|
try {
|
|
return $conn->getPrimaryPos();
|
|
} finally {
|
|
$this->closeConnection( $conn );
|
|
}
|
|
}
|
|
|
|
public function getMasterPos() {
|
|
// wfDeprecated( __METHOD__, '1.37' );
|
|
return $this->getPrimaryPos();
|
|
}
|
|
|
|
public function getReplicaResumePos() {
|
|
// Get the position of any existing master server connection
|
|
$masterConn = $this->getAnyOpenConnection( $this->getWriterIndex() );
|
|
if ( $masterConn ) {
|
|
return $masterConn->getPrimaryPos();
|
|
}
|
|
|
|
// Get the highest position of any existing replica server connection
|
|
$highestPos = false;
|
|
foreach ( $this->getStreamingReplicaIndexes() as $i ) {
|
|
$conn = $this->getAnyOpenConnection( $i );
|
|
$pos = $conn ? $conn->getReplicaPos() : false;
|
|
if ( !$pos ) {
|
|
continue; // no open connection or could not get position
|
|
}
|
|
|
|
$highestPos = $highestPos ?: $pos;
|
|
if ( $pos->hasReached( $highestPos ) ) {
|
|
$highestPos = $pos;
|
|
}
|
|
}
|
|
|
|
return $highestPos;
|
|
}
|
|
|
|
public function disable( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
$this->closeAll( $fname, $owner );
|
|
$this->disabled = true;
|
|
}
|
|
|
|
public function closeAll( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
$this->forEachOpenConnection( function ( IDatabase $conn ) use ( $fname ) {
|
|
$srvName = $conn->getServerName();
|
|
$this->connLogger->debug( "$fname: closing connection to database '$srvName'." );
|
|
$conn->close( $fname, $this->id );
|
|
} );
|
|
|
|
$this->conns = self::newTrackedConnectionsArray();
|
|
}
|
|
|
|
public function closeConnection( IDatabase $conn ) {
|
|
if ( $conn instanceof DBConnRef ) {
|
|
// Avoid calling close() but still leaving the handle in the pool
|
|
throw new RuntimeException( 'Cannot close DBConnRef instance; it must be shareable' );
|
|
}
|
|
|
|
$serverIndex = $conn->getLBInfo( self::INFO_SERVER_INDEX );
|
|
if ( $serverIndex === null ) {
|
|
throw new RuntimeException( 'Database handle is missing server index' );
|
|
}
|
|
|
|
$srvName = $this->getServerName( $serverIndex );
|
|
$domain = $conn->getDomainID();
|
|
|
|
$found = false;
|
|
foreach ( $this->conns as $type => $connsByServer ) {
|
|
$key = array_search( $conn, $connsByServer[$serverIndex] ?? [], true );
|
|
if ( $key !== false ) {
|
|
$found = true;
|
|
unset( $this->conns[$type][$serverIndex][$key] );
|
|
}
|
|
}
|
|
|
|
if ( !$found ) {
|
|
$this->connLogger->warning(
|
|
__METHOD__ .
|
|
": got orphaned connection to database $serverIndex/$domain at '$srvName'."
|
|
);
|
|
}
|
|
|
|
$this->connLogger->debug(
|
|
__METHOD__ .
|
|
": closing connection to database $serverIndex/$domain at '$srvName'."
|
|
);
|
|
|
|
$conn->close( __METHOD__ );
|
|
}
|
|
|
|
public function commitAll( $fname = __METHOD__, $owner = null ) {
|
|
$this->commitMasterChanges( $fname, $owner );
|
|
$this->flushMasterSnapshots( $fname, $owner );
|
|
$this->flushReplicaSnapshots( $fname, $owner );
|
|
}
|
|
|
|
public function finalizePrimaryChanges( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
$this->assertTransactionRoundStage( [ self::ROUND_CURSORY, self::ROUND_FINALIZED ] );
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
// Loop until callbacks stop adding callbacks on other connections
|
|
$total = 0;
|
|
do {
|
|
$count = 0; // callbacks execution attempts
|
|
$this->forEachOpenMasterConnection( static function ( Database $conn ) use ( &$count ) {
|
|
// Run any pre-commit callbacks while leaving the post-commit ones suppressed.
|
|
// Any error should cause all (peer) transactions to be rolled back together.
|
|
$count += $conn->runOnTransactionPreCommitCallbacks();
|
|
} );
|
|
$total += $count;
|
|
} while ( $count > 0 );
|
|
// Defer post-commit callbacks until after COMMIT/ROLLBACK happens on all handles
|
|
$this->forEachOpenMasterConnection( static function ( Database $conn ) {
|
|
$conn->setTrxEndCallbackSuppression( true );
|
|
} );
|
|
$this->trxRoundStage = self::ROUND_FINALIZED;
|
|
|
|
return $total;
|
|
}
|
|
|
|
public function finalizeMasterChanges( $fname = __METHOD__, $owner = null ) {
|
|
// wfDeprecated( __METHOD__, '1.37' );
|
|
return $this->finalizePrimaryChanges( $fname, $owner );
|
|
}
|
|
|
|
public function approvePrimaryChanges( array $options, $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
$this->assertTransactionRoundStage( self::ROUND_FINALIZED );
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
$limit = $options['maxWriteDuration'] ?? 0;
|
|
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
$this->forEachOpenMasterConnection( function ( IDatabase $conn ) use ( $limit ) {
|
|
// If atomic sections or explicit transactions are still open, some caller must have
|
|
// caught an exception but failed to properly rollback any changes. Detect that and
|
|
// throw an error (causing rollback).
|
|
$conn->assertNoOpenTransactions();
|
|
// Assert that the time to replicate the transaction will be sane.
|
|
// If this fails, then all DB transactions will be rollback back together.
|
|
$time = $conn->pendingWriteQueryDuration( $conn::ESTIMATE_DB_APPLY );
|
|
if ( $limit > 0 ) {
|
|
if ( $time > $limit ) {
|
|
throw new DBTransactionSizeError(
|
|
$conn,
|
|
"Transaction spent $time second(s) in writes, exceeding the limit of $limit",
|
|
[ $time, $limit ]
|
|
);
|
|
} elseif ( $time > 0 ) {
|
|
$this->perfLogger->debug( "Transaction spent $time second(s) in writes, " .
|
|
"less than the limit of $limit" );
|
|
}
|
|
}
|
|
// If a connection sits idle while slow queries execute on another, that connection
|
|
// may end up dropped before the commit round is reached. Ping servers to detect this.
|
|
if ( $conn->writesOrCallbacksPending() && !$conn->ping() ) {
|
|
throw new DBTransactionError(
|
|
$conn,
|
|
"A connection to the {$conn->getDBname()} database was lost before commit"
|
|
);
|
|
}
|
|
} );
|
|
$this->trxRoundStage = self::ROUND_APPROVED;
|
|
}
|
|
|
|
public function approveMasterChanges( array $options, $fname = __METHOD__, $owner = null ) {
|
|
// wfDeprecated( __METHOD__, '1.37' );
|
|
$this->approvePrimaryChanges( $options, $fname, $owner );
|
|
}
|
|
|
|
public function beginMasterChanges( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
if ( $this->trxRoundId !== false ) {
|
|
throw new DBTransactionError(
|
|
null,
|
|
"$fname: Transaction round '{$this->trxRoundId}' already started"
|
|
);
|
|
}
|
|
$this->assertTransactionRoundStage( self::ROUND_CURSORY );
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
// Clear any empty transactions (no writes/callbacks) from the implicit round
|
|
$this->flushMasterSnapshots( $fname, $owner );
|
|
|
|
$this->trxRoundId = $fname;
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
// Mark applicable handles as participating in this explicit transaction round.
|
|
// For each of these handles, any writes and callbacks will be tied to a single
|
|
// transaction. The (peer) handles will reject begin()/commit() calls unless they
|
|
// are part of an en masse commit or an en masse rollback.
|
|
$this->forEachOpenMasterConnection( function ( Database $conn ) {
|
|
$this->applyTransactionRoundFlags( $conn );
|
|
} );
|
|
$this->trxRoundStage = self::ROUND_CURSORY;
|
|
}
|
|
|
|
public function commitMasterChanges( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
$this->assertTransactionRoundStage( self::ROUND_APPROVED );
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
$failures = [];
|
|
|
|
$restore = ( $this->trxRoundId !== false );
|
|
$this->trxRoundId = false;
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
// Commit any writes and clear any snapshots as well (callbacks require AUTOCOMMIT).
|
|
// Note that callbacks should already be suppressed due to finalizePrimaryChanges().
|
|
$this->forEachOpenMasterConnection(
|
|
function ( IDatabase $conn ) use ( $fname, &$failures ) {
|
|
try {
|
|
$conn->commit( $fname, $conn::FLUSHING_ALL_PEERS );
|
|
} catch ( DBError $e ) {
|
|
( $this->errorLogger )( $e );
|
|
$failures[] = "{$conn->getServerName()}: {$e->getMessage()}";
|
|
}
|
|
}
|
|
);
|
|
if ( $failures ) {
|
|
throw new DBTransactionError(
|
|
null,
|
|
"$fname: Commit failed on server(s) " . implode( "\n", array_unique( $failures ) )
|
|
);
|
|
}
|
|
if ( $restore ) {
|
|
// Unmark handles as participating in this explicit transaction round
|
|
$this->forEachOpenMasterConnection( function ( Database $conn ) {
|
|
$this->undoTransactionRoundFlags( $conn );
|
|
} );
|
|
}
|
|
$this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
|
|
}
|
|
|
|
public function runMasterTransactionIdleCallbacks( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
if ( $this->trxRoundStage === self::ROUND_COMMIT_CALLBACKS ) {
|
|
$type = IDatabase::TRIGGER_COMMIT;
|
|
} elseif ( $this->trxRoundStage === self::ROUND_ROLLBACK_CALLBACKS ) {
|
|
$type = IDatabase::TRIGGER_ROLLBACK;
|
|
} else {
|
|
throw new DBTransactionError(
|
|
null,
|
|
"Transaction should be in the callback stage (not '{$this->trxRoundStage}')"
|
|
);
|
|
}
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
$oldStage = $this->trxRoundStage;
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
|
|
// Now that the COMMIT/ROLLBACK step is over, enable post-commit callback runs
|
|
$this->forEachOpenMasterConnection( static function ( Database $conn ) {
|
|
$conn->setTrxEndCallbackSuppression( false );
|
|
} );
|
|
|
|
$errors = [];
|
|
$fname = __METHOD__;
|
|
// Loop until callbacks stop adding callbacks on other connections
|
|
do {
|
|
// Run any pending callbacks for each connection...
|
|
$count = 0; // callback execution attempts
|
|
$this->forEachOpenMasterConnection(
|
|
static function ( Database $conn ) use ( $type, &$errors, &$count ) {
|
|
if ( $conn->trxLevel() ) {
|
|
return; // retry in the next iteration, after commit() is called
|
|
}
|
|
$count += $conn->runOnTransactionIdleCallbacks( $type, $errors );
|
|
}
|
|
);
|
|
// Clear out any active transactions left over from callbacks...
|
|
$this->forEachOpenMasterConnection(
|
|
function ( Database $conn ) use ( &$errors, $fname ) {
|
|
if ( $conn->writesPending() ) {
|
|
// A callback from another handle wrote to this one and DBO_TRX is set
|
|
$this->queryLogger->warning( $fname . ": found writes pending." );
|
|
$fnames = implode( ', ', $conn->pendingWriteAndCallbackCallers() );
|
|
$this->queryLogger->warning(
|
|
"$fname: found writes pending ($fnames).",
|
|
$this->getConnLogContext(
|
|
$conn,
|
|
[ 'exception' => new RuntimeException() ]
|
|
)
|
|
);
|
|
} elseif ( $conn->trxLevel() ) {
|
|
// A callback from another handle read from this one and DBO_TRX is set,
|
|
// which can easily happen if there is only one DB (no replicas)
|
|
$this->queryLogger->debug( "$fname: found empty transaction." );
|
|
}
|
|
try {
|
|
$conn->commit( $fname, $conn::FLUSHING_ALL_PEERS );
|
|
} catch ( DBError $ex ) {
|
|
$errors[] = $ex;
|
|
}
|
|
}
|
|
);
|
|
} while ( $count > 0 );
|
|
|
|
$this->trxRoundStage = $oldStage;
|
|
|
|
return $errors ? $errors[0] : null;
|
|
}
|
|
|
|
public function runMasterTransactionListenerCallbacks( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
if ( $this->trxRoundStage === self::ROUND_COMMIT_CALLBACKS ) {
|
|
$type = IDatabase::TRIGGER_COMMIT;
|
|
} elseif ( $this->trxRoundStage === self::ROUND_ROLLBACK_CALLBACKS ) {
|
|
$type = IDatabase::TRIGGER_ROLLBACK;
|
|
} else {
|
|
throw new DBTransactionError(
|
|
null,
|
|
"Transaction should be in the callback stage (not '{$this->trxRoundStage}')"
|
|
);
|
|
}
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
$errors = [];
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
$this->forEachOpenMasterConnection(
|
|
static function ( Database $conn ) use ( $type, &$errors ) {
|
|
$conn->runTransactionListenerCallbacks( $type, $errors );
|
|
}
|
|
);
|
|
$this->trxRoundStage = self::ROUND_CURSORY;
|
|
|
|
return $errors ? $errors[0] : null;
|
|
}
|
|
|
|
public function rollbackMasterChanges( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
if ( $this->ownerId === null ) {
|
|
/** @noinspection PhpUnusedLocalVariableInspection */
|
|
$scope = ScopedCallback::newScopedIgnoreUserAbort();
|
|
}
|
|
|
|
$restore = ( $this->trxRoundId !== false );
|
|
$this->trxRoundId = false;
|
|
$this->trxRoundStage = self::ROUND_ERROR; // "failed" until proven otherwise
|
|
$this->forEachOpenMasterConnection( static function ( IDatabase $conn ) use ( $fname ) {
|
|
$conn->rollback( $fname, $conn::FLUSHING_ALL_PEERS );
|
|
} );
|
|
if ( $restore ) {
|
|
// Unmark handles as participating in this explicit transaction round
|
|
$this->forEachOpenMasterConnection( function ( Database $conn ) {
|
|
$this->undoTransactionRoundFlags( $conn );
|
|
} );
|
|
}
|
|
$this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
|
|
}
|
|
|
|
/**
|
|
* @param string|string[] $stage
|
|
* @throws DBTransactionError
|
|
*/
|
|
private function assertTransactionRoundStage( $stage ) {
|
|
$stages = (array)$stage;
|
|
|
|
if ( !in_array( $this->trxRoundStage, $stages, true ) ) {
|
|
$stageList = implode(
|
|
'/',
|
|
array_map( static function ( $v ) {
|
|
return "'$v'";
|
|
}, $stages )
|
|
);
|
|
throw new DBTransactionError(
|
|
null,
|
|
"Transaction round stage must be $stageList (not '{$this->trxRoundStage}')"
|
|
);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Assure that if this instance is owned, the caller is either the owner or is internal
|
|
*
|
|
* If an LBFactory owns the LoadBalancer, then certain methods should only called through
|
|
* that LBFactory to avoid broken contracts. Otherwise, those methods can publically be
|
|
* called by anything. In any case, internal methods from the LoadBalancer itself should
|
|
* always be allowed.
|
|
*
|
|
* @param string $fname
|
|
* @param int|null $owner Owner ID of the caller
|
|
* @throws DBTransactionError
|
|
*/
|
|
private function assertOwnership( $fname, $owner ) {
|
|
if ( $this->ownerId !== null && $owner !== $this->ownerId && $owner !== $this->id ) {
|
|
throw new DBTransactionError(
|
|
null,
|
|
"$fname: LoadBalancer is owned by ID '{$this->ownerId}' (got '$owner')."
|
|
);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Make all DB servers with DBO_DEFAULT/DBO_TRX set join the transaction round
|
|
*
|
|
* Some servers may have neither flag enabled, meaning that they opt out of such
|
|
* transaction rounds and remain in auto-commit mode. Such behavior might be desired
|
|
* when a DB server is used for something like simple key/value storage.
|
|
*
|
|
* @param Database $conn
|
|
*/
|
|
private function applyTransactionRoundFlags( Database $conn ) {
|
|
if ( $conn->getLBInfo( self::INFO_AUTOCOMMIT_ONLY ) ) {
|
|
return; // transaction rounds do not apply to these connections
|
|
}
|
|
|
|
if ( $conn->getFlag( $conn::DBO_DEFAULT ) ) {
|
|
// DBO_TRX is controlled entirely by CLI mode presence with DBO_DEFAULT.
|
|
// Force DBO_TRX even in CLI mode since a commit round is expected soon.
|
|
$conn->setFlag( $conn::DBO_TRX, $conn::REMEMBER_PRIOR );
|
|
}
|
|
|
|
if ( $conn->getFlag( $conn::DBO_TRX ) ) {
|
|
$conn->setLBInfo( $conn::LB_TRX_ROUND_ID, $this->trxRoundId );
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @param Database $conn
|
|
*/
|
|
private function undoTransactionRoundFlags( Database $conn ) {
|
|
if ( $conn->getLBInfo( self::INFO_AUTOCOMMIT_ONLY ) ) {
|
|
return; // transaction rounds do not apply to these connections
|
|
}
|
|
|
|
if ( $conn->getFlag( $conn::DBO_TRX ) ) {
|
|
$conn->setLBInfo( $conn::LB_TRX_ROUND_ID, null ); // remove the round ID
|
|
}
|
|
|
|
if ( $conn->getFlag( $conn::DBO_DEFAULT ) ) {
|
|
$conn->restoreFlags( $conn::RESTORE_PRIOR );
|
|
}
|
|
}
|
|
|
|
public function flushReplicaSnapshots( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
$this->forEachOpenReplicaConnection( static function ( IDatabase $conn ) use ( $fname ) {
|
|
$conn->flushSnapshot( $fname );
|
|
} );
|
|
}
|
|
|
|
public function flushMasterSnapshots( $fname = __METHOD__, $owner = null ) {
|
|
$this->assertOwnership( $fname, $owner );
|
|
$this->forEachOpenMasterConnection( static function ( IDatabase $conn ) use ( $fname ) {
|
|
$conn->flushSnapshot( $fname );
|
|
} );
|
|
}
|
|
|
|
/**
|
|
* @return string
|
|
* @since 1.32
|
|
*/
|
|
public function getTransactionRoundStage() {
|
|
return $this->trxRoundStage;
|
|
}
|
|
|
|
public function hasMasterConnection() {
|
|
return $this->isOpen( $this->getWriterIndex() );
|
|
}
|
|
|
|
public function hasMasterChanges() {
|
|
$pending = false;
|
|
$this->forEachOpenMasterConnection( static function ( IDatabase $conn ) use ( &$pending ) {
|
|
$pending = $pending || $conn->writesOrCallbacksPending();
|
|
} );
|
|
|
|
return $pending;
|
|
}
|
|
|
|
public function lastMasterChangeTimestamp() {
|
|
$lastTime = false;
|
|
$this->forEachOpenMasterConnection( static function ( IDatabase $conn ) use ( &$lastTime ) {
|
|
$lastTime = max( $lastTime, $conn->lastDoneWrites() );
|
|
} );
|
|
|
|
return $lastTime;
|
|
}
|
|
|
|
public function hasOrMadeRecentMasterChanges( $age = null ) {
|
|
$age = $age ?? $this->waitTimeout;
|
|
|
|
return ( $this->hasMasterChanges()
|
|
|| $this->lastMasterChangeTimestamp() > microtime( true ) - $age );
|
|
}
|
|
|
|
public function pendingMasterChangeCallers() {
|
|
$fnames = [];
|
|
$this->forEachOpenMasterConnection( static function ( IDatabase $conn ) use ( &$fnames ) {
|
|
$fnames = array_merge( $fnames, $conn->pendingWriteCallers() );
|
|
} );
|
|
|
|
return $fnames;
|
|
}
|
|
|
|
public function getLaggedReplicaMode( $domain = false ) {
|
|
$domain = $this->resolveDomainID( $domain );
|
|
|
|
if ( $this->laggedReplicaMode ) {
|
|
// Stay in lagged replica mode once it is observed on any domain
|
|
return true;
|
|
}
|
|
|
|
if ( $this->hasStreamingReplicaServers() ) {
|
|
// This will set "laggedReplicaMode" as needed
|
|
$this->getReaderIndex( self::GROUP_GENERIC, $domain );
|
|
}
|
|
|
|
return $this->laggedReplicaMode;
|
|
}
|
|
|
|
public function laggedReplicaUsed() {
|
|
return $this->laggedReplicaMode;
|
|
}
|
|
|
|
public function getReadOnlyReason( $domain = false ) {
|
|
$domainInstance = DatabaseDomain::newFromId( $this->resolveDomainID( $domain ) );
|
|
|
|
if ( $this->readOnlyReason !== false ) {
|
|
return $this->readOnlyReason;
|
|
} elseif ( $this->isMasterRunningReadOnly( $domainInstance ) ) {
|
|
return 'The primary database server is running in read-only mode.';
|
|
} elseif ( $this->getLaggedReplicaMode( $domain ) ) {
|
|
$genericIndex = $this->getExistingReaderIndex( self::GROUP_GENERIC );
|
|
|
|
return ( $genericIndex !== self::READER_INDEX_NONE )
|
|
? 'The database is read-only until replication lag decreases.'
|
|
: 'The database is read-only until a replica database server becomes reachable.';
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* @note This method suppresses DBError exceptions in order to avoid severe downtime
|
|
* @param IDatabase $conn Primary connection
|
|
* @param int $flags Bitfield of class CONN_* constants
|
|
* @return bool Whether the entire server or currently selected DB/schema is read-only
|
|
*/
|
|
private function isMasterConnectionReadOnly( IDatabase $conn, $flags = 0 ) {
|
|
// Note that table prefixes are not related to server-side read-only mode
|
|
$key = $this->srvCache->makeGlobalKey(
|
|
'rdbms-server-readonly',
|
|
$conn->getServerName(),
|
|
$conn->getDBname(),
|
|
(string)$conn->dbSchema()
|
|
);
|
|
|
|
if ( self::fieldHasBit( $flags, self::CONN_REFRESH_READ_ONLY ) ) {
|
|
// Refresh the local server cache. This is useful when the caller is
|
|
// currently in the process of updating a corresponding WANCache key.
|
|
try {
|
|
$readOnly = (int)$conn->serverIsReadOnly();
|
|
} catch ( DBError $e ) {
|
|
$readOnly = 0;
|
|
}
|
|
$this->srvCache->set( $key, $readOnly, BagOStuff::TTL_PROC_SHORT );
|
|
} else {
|
|
$readOnly = $this->srvCache->getWithSetCallback(
|
|
$key,
|
|
BagOStuff::TTL_PROC_SHORT,
|
|
static function () use ( $conn ) {
|
|
try {
|
|
$readOnly = (int)$conn->serverIsReadOnly();
|
|
} catch ( DBError $e ) {
|
|
$readOnly = 0;
|
|
}
|
|
|
|
return $readOnly;
|
|
}
|
|
);
|
|
}
|
|
|
|
return (bool)$readOnly;
|
|
}
|
|
|
|
/**
|
|
* @note This method suppresses DBError exceptions in order to avoid severe downtime
|
|
* @param DatabaseDomain $domain
|
|
* @return bool Whether the entire master server or the local domain DB is read-only
|
|
*/
|
|
private function isMasterRunningReadOnly( DatabaseDomain $domain ) {
|
|
// Context will often be HTTP GET/HEAD; heavily cache the results
|
|
return (bool)$this->wanCache->getWithSetCallback(
|
|
// Note that table prefixes are not related to server-side read-only mode
|
|
$this->wanCache->makeGlobalKey(
|
|
'rdbms-server-readonly',
|
|
$this->getMasterServerName(),
|
|
$domain->getDatabase(),
|
|
(string)$domain->getSchema()
|
|
),
|
|
self::TTL_CACHE_READONLY,
|
|
function () use ( $domain ) {
|
|
$scope = $this->trxProfiler->silenceForScope();
|
|
|
|
$index = $this->getWriterIndex();
|
|
// Refresh the local server cache as well. This is done in order to avoid
|
|
// backfilling the WANCache with data that is already significantly stale
|
|
$flags = self::CONN_SILENCE_ERRORS | self::CONN_REFRESH_READ_ONLY;
|
|
$conn = $this->getServerConnection( $index, $domain->getId(), $flags );
|
|
if ( $conn ) {
|
|
try {
|
|
$readOnly = (int)$this->isMasterConnectionReadOnly( $conn );
|
|
} catch ( DBError $e ) {
|
|
$readOnly = 0;
|
|
}
|
|
$this->reuseConnection( $conn );
|
|
} else {
|
|
$readOnly = 0;
|
|
}
|
|
|
|
ScopedCallback::consume( $scope );
|
|
|
|
return $readOnly;
|
|
},
|
|
[
|
|
'busyValue' => 0,
|
|
'pcTTL' => WANObjectCache::TTL_PROC_LONG
|
|
]
|
|
);
|
|
}
|
|
|
|
public function allowLagged( $mode = null ) {
|
|
if ( $mode === null ) {
|
|
return $this->allowLagged;
|
|
}
|
|
$this->allowLagged = $mode;
|
|
|
|
return $this->allowLagged;
|
|
}
|
|
|
|
public function pingAll() {
|
|
$success = true;
|
|
$this->forEachOpenConnection( static function ( IDatabase $conn ) use ( &$success ) {
|
|
if ( !$conn->ping() ) {
|
|
$success = false;
|
|
}
|
|
} );
|
|
|
|
return $success;
|
|
}
|
|
|
|
public function forEachOpenConnection( $callback, array $params = [] ) {
|
|
foreach ( $this->conns as $connsByServer ) {
|
|
foreach ( $connsByServer as $serverConns ) {
|
|
foreach ( $serverConns as $conn ) {
|
|
$callback( $conn, ...$params );
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public function forEachOpenMasterConnection( $callback, array $params = [] ) {
|
|
$masterIndex = $this->getWriterIndex();
|
|
foreach ( $this->conns as $connsByServer ) {
|
|
if ( isset( $connsByServer[$masterIndex] ) ) {
|
|
/** @var IDatabase $conn */
|
|
foreach ( $connsByServer[$masterIndex] as $conn ) {
|
|
$callback( $conn, ...$params );
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
public function forEachOpenReplicaConnection( $callback, array $params = [] ) {
|
|
foreach ( $this->conns as $connsByServer ) {
|
|
foreach ( $connsByServer as $i => $serverConns ) {
|
|
if ( $i === $this->getWriterIndex() ) {
|
|
continue; // skip master
|
|
}
|
|
foreach ( $serverConns as $conn ) {
|
|
$callback( $conn, ...$params );
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @return int
|
|
*/
|
|
private function getCurrentConnectionCount() {
|
|
$count = 0;
|
|
foreach ( $this->conns as $connsByServer ) {
|
|
foreach ( $connsByServer as $serverConns ) {
|
|
$count += count( $serverConns );
|
|
}
|
|
}
|
|
|
|
return $count;
|
|
}
|
|
|
|
public function getMaxLag( $domain = false ) {
|
|
$domain = $this->resolveDomainID( $domain );
|
|
|
|
$host = '';
|
|
$maxLag = -1;
|
|
$maxIndex = 0;
|
|
|
|
if ( $this->hasReplicaServers() ) {
|
|
$lagTimes = $this->getLagTimes( $domain );
|
|
foreach ( $lagTimes as $i => $lag ) {
|
|
if ( $this->groupLoads[self::GROUP_GENERIC][$i] > 0 && $lag > $maxLag ) {
|
|
$maxLag = $lag;
|
|
$host = $this->getServerInfoStrict( $i, 'host' );
|
|
$maxIndex = $i;
|
|
}
|
|
}
|
|
}
|
|
|
|
return [ $host, $maxLag, $maxIndex ];
|
|
}
|
|
|
|
public function getLagTimes( $domain = false ) {
|
|
$domain = $this->resolveDomainID( $domain );
|
|
|
|
if ( !$this->hasReplicaServers() ) {
|
|
return [ $this->getWriterIndex() => 0 ]; // no replication = no lag
|
|
}
|
|
|
|
$knownLagTimes = []; // map of (server index => 0 seconds)
|
|
$indexesWithLag = [];
|
|
foreach ( $this->servers as $i => $server ) {
|
|
if ( empty( $server['is static'] ) ) {
|
|
$indexesWithLag[] = $i; // DB server might have replication lag
|
|
} else {
|
|
$knownLagTimes[$i] = 0; // DB server is a non-replicating and read-only archive
|
|
}
|
|
}
|
|
|
|
return $this->getLoadMonitor()->getLagTimes( $indexesWithLag, $domain ) + $knownLagTimes;
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
* @deprecated Since 1.34 Use IDatabase::getLag() instead
|
|
*/
|
|
public function safeGetLag( IDatabase $conn ) {
|
|
return $conn->getLag();
|
|
}
|
|
|
|
public function waitForMasterPos( IDatabase $conn, $pos = false, $timeout = null ) {
|
|
$timeout = max( 1, $timeout ?: $this->waitTimeout );
|
|
|
|
if ( $conn->getLBInfo( self::INFO_SERVER_INDEX ) === $this->getWriterIndex() ) {
|
|
return true; // not a replica DB server
|
|
}
|
|
|
|
if ( !$pos ) {
|
|
// Get the current master position, opening a connection only if needed
|
|
$this->replLogger->debug( __METHOD__ . ': no position passed; using current' );
|
|
$index = $this->getWriterIndex();
|
|
$flags = self::CONN_SILENCE_ERRORS;
|
|
$masterConn = $this->getAnyOpenConnection( $index, $flags );
|
|
if ( $masterConn ) {
|
|
$pos = $masterConn->getPrimaryPos();
|
|
} else {
|
|
$masterConn = $this->getServerConnection( $index, self::DOMAIN_ANY, $flags );
|
|
if ( !$masterConn ) {
|
|
throw new DBReplicationWaitError(
|
|
null,
|
|
"Could not obtain a primary database connection to get the position"
|
|
);
|
|
}
|
|
$pos = $masterConn->getPrimaryPos();
|
|
$this->closeConnection( $masterConn );
|
|
}
|
|
}
|
|
|
|
if ( $pos instanceof DBPrimaryPos ) {
|
|
$this->replLogger->debug( __METHOD__ . ': waiting' );
|
|
$result = $conn->masterPosWait( $pos, $timeout );
|
|
$ok = ( $result !== null && $result != -1 );
|
|
if ( $ok ) {
|
|
$this->replLogger->debug( __METHOD__ . ': done waiting (success)' );
|
|
} else {
|
|
$this->replLogger->debug( __METHOD__ . ': done waiting (failure)' );
|
|
}
|
|
} else {
|
|
$ok = false; // something is misconfigured
|
|
$this->replLogger->error(
|
|
__METHOD__ . ': could not get master pos for {db_server}',
|
|
$this->getConnLogContext( $conn, [ 'exception' => new RuntimeException() ] )
|
|
);
|
|
}
|
|
|
|
return $ok;
|
|
}
|
|
|
|
public function setTransactionListener( $name, callable $callback = null ) {
|
|
if ( $callback ) {
|
|
$this->trxRecurringCallbacks[$name] = $callback;
|
|
} else {
|
|
unset( $this->trxRecurringCallbacks[$name] );
|
|
}
|
|
$this->forEachOpenMasterConnection(
|
|
static function ( IDatabase $conn ) use ( $name, $callback ) {
|
|
$conn->setTransactionListener( $name, $callback );
|
|
}
|
|
);
|
|
}
|
|
|
|
public function setTableAliases( array $aliases ) {
|
|
$this->tableAliases = $aliases;
|
|
}
|
|
|
|
public function setIndexAliases( array $aliases ) {
|
|
$this->indexAliases = $aliases;
|
|
}
|
|
|
|
public function setDomainAliases( array $aliases ) {
|
|
$this->domainAliases = $aliases;
|
|
}
|
|
|
|
public function setLocalDomainPrefix( $prefix ) {
|
|
// Find connections to explicit foreign domains still marked as in-use...
|
|
$domainsInUse = [];
|
|
$this->forEachOpenConnection( static function ( IDatabase $conn ) use ( &$domainsInUse ) {
|
|
// Once reuseConnection() is called on a handle, its reference count goes from 1 to 0.
|
|
// Until then, it is still in use by the caller (explicitly or via DBConnRef scope).
|
|
if ( $conn->getLBInfo( self::INFO_FOREIGN_REF_COUNT ) > 0 ) {
|
|
$domainsInUse[] = $conn->getDomainID();
|
|
}
|
|
} );
|
|
|
|
// Do not switch connections to explicit foreign domains unless marked as safe
|
|
if ( $domainsInUse ) {
|
|
$domains = implode( ', ', $domainsInUse );
|
|
throw new DBUnexpectedError( null,
|
|
"Foreign domain connections are still in use ($domains)" );
|
|
}
|
|
|
|
$this->setLocalDomain( new DatabaseDomain(
|
|
$this->localDomain->getDatabase(),
|
|
$this->localDomain->getSchema(),
|
|
$prefix
|
|
) );
|
|
|
|
// Update the prefix for all local connections...
|
|
$this->forEachOpenConnection( static function ( IDatabase $conn ) use ( $prefix ) {
|
|
if ( !$conn->getLBInfo( self::INFO_FORIEGN ) ) {
|
|
$conn->tablePrefix( $prefix );
|
|
}
|
|
} );
|
|
}
|
|
|
|
public function redefineLocalDomain( $domain ) {
|
|
$this->closeAll( __METHOD__, $this->id );
|
|
|
|
$this->setLocalDomain( DatabaseDomain::newFromId( $domain ) );
|
|
}
|
|
|
|
public function setTempTablesOnlyMode( $value, $domain ) {
|
|
$old = $this->tempTablesOnlyMode[$domain] ?? false;
|
|
if ( $value ) {
|
|
$this->tempTablesOnlyMode[$domain] = true;
|
|
} else {
|
|
unset( $this->tempTablesOnlyMode[$domain] );
|
|
}
|
|
|
|
return $old;
|
|
}
|
|
|
|
/**
|
|
* @param DatabaseDomain $domain
|
|
*/
|
|
private function setLocalDomain( DatabaseDomain $domain ) {
|
|
$this->localDomain = $domain;
|
|
}
|
|
|
|
/**
|
|
* @param int $i Server index
|
|
* @param string|null $field Server index field [optional]
|
|
* @return array|mixed
|
|
* @throws InvalidArgumentException
|
|
*/
|
|
private function getServerInfoStrict( $i, $field = null ) {
|
|
if ( !isset( $this->servers[$i] ) || !is_array( $this->servers[$i] ) ) {
|
|
throw new InvalidArgumentException( "No server with index '$i'" );
|
|
}
|
|
|
|
if ( $field !== null ) {
|
|
if ( !array_key_exists( $field, $this->servers[$i] ) ) {
|
|
throw new InvalidArgumentException( "No field '$field' in server index '$i'" );
|
|
}
|
|
|
|
return $this->servers[$i][$field];
|
|
}
|
|
|
|
return $this->servers[$i];
|
|
}
|
|
|
|
/**
|
|
* @return string Name of the master server of the relevant DB cluster (e.g. "db1052")
|
|
*/
|
|
private function getMasterServerName() {
|
|
return $this->getServerName( $this->getWriterIndex() );
|
|
}
|
|
|
|
/**
|
|
* @param int $flags A bitfield of flags
|
|
* @param int $bit Bit flag constant
|
|
* @return bool Whether the bit field has the specified bit flag set
|
|
*/
|
|
private function fieldHasBit( int $flags, int $bit ) {
|
|
return ( ( $flags & $bit ) === $bit );
|
|
}
|
|
|
|
/**
|
|
* Create a log context to pass to PSR-3 logger functions.
|
|
*
|
|
* @param IDatabase $conn
|
|
* @param array $extras Additional data to add to context
|
|
* @return array
|
|
*/
|
|
protected function getConnLogContext( IDatabase $conn, array $extras = [] ) {
|
|
return array_merge(
|
|
[
|
|
'db_server' => $conn->getServerName(),
|
|
'db_domain' => $conn->getDomainID()
|
|
],
|
|
$extras
|
|
);
|
|
}
|
|
|
|
public function __destruct() {
|
|
// Avoid connection leaks for sanity
|
|
$this->disable( __METHOD__, $this->ownerId );
|
|
}
|
|
}
|
|
|
|
/**
|
|
* @deprecated since 1.29
|
|
*/
|
|
class_alias( LoadBalancer::class, 'LoadBalancer' );
|