includes/libs/rdbms/lbfactory/LBFactory.php
<?php
/**
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
* http://www.gnu.org/copyleft/gpl.html
*
* @file
*/
namespace Wikimedia\Rdbms;
use Exception;
use Generator;
use Liuggio\StatsdClient\Factory\StatsdDataFactoryInterface;
use NullStatsdDataFactory;
use Psr\Log\LoggerInterface;
use Psr\Log\NullLogger;
use RuntimeException;
use Throwable;
use WANObjectCache;
use Wikimedia\ObjectCache\BagOStuff;
use Wikimedia\ObjectCache\EmptyBagOStuff;
use Wikimedia\RequestTimeout\CriticalSectionProvider;
use Wikimedia\ScopedCallback;
/**
* @see ILBFactory
* @ingroup Database
*/
abstract class LBFactory implements ILBFactory {
/** @var CriticalSectionProvider|null */
private $csProvider;
/**
* @var callable|null An optional callback that returns a ScopedCallback instance,
* meant to profile the actual query execution in {@see Database::doQuery}
*/
private $profiler;
/** @var TransactionProfiler */
private $trxProfiler;
/** @var StatsdDataFactoryInterface */
private $statsd;
/** @var LoggerInterface */
private $logger;
/** @var callable Error logger */
private $errorLogger;
/** @var callable Deprecation logger */
private $deprecationLogger;
/** @var ChronologyProtector */
protected $chronologyProtector;
/** @var BagOStuff */
protected $srvCache;
/** @var WANObjectCache */
protected $wanCache;
/** @var DatabaseDomain Local domain */
protected $localDomain;
/** @var bool Whether this PHP instance is for a CLI script */
private $cliMode;
/** @var string Agent name for query profiling */
private $agent;
/** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
private $tableAliases = [];
/** @var string[] Map of (index alias => index) */
private $indexAliases = [];
/** @var DatabaseDomain[]|string[] Map of (domain alias => DB domain) */
protected $domainAliases = [];
/** @var array[] Map of virtual domain to array of cluster and domain */
protected array $virtualDomainsMapping = [];
/** @var string[] List of registered virtual domains */
protected array $virtualDomains = [];
/** @var callable[] */
private $replicationWaitCallbacks = [];
/** @var int|null Ticket used to delegate transaction ownership */
private $ticket;
/** @var string|false String if a requested DBO_TRX transaction round is active */
private $trxRoundId = false;
/** @var string One of the ROUND_* class constants */
private $trxRoundStage = self::ROUND_CURSORY;
/** @var int Default replication wait timeout */
private $replicationWaitTimeout;
/** @var string|false Reason all LBs are read-only or false if not */
protected $readOnlyReason = false;
/** @var string|null */
private $defaultGroup = null;
private const ROUND_CURSORY = 'cursory';
private const ROUND_BEGINNING = 'within-begin';
private const ROUND_COMMITTING = 'within-commit';
private const ROUND_ROLLING_BACK = 'within-rollback';
private const ROUND_COMMIT_CALLBACKS = 'within-commit-callbacks';
private const ROUND_ROLLBACK_CALLBACKS = 'within-rollback-callbacks';
private const ROUND_ROLLBACK_SESSIONS = 'within-rollback-session';
/**
* @var callable
*/
private $configCallback = null;
public function __construct( array $conf ) {
$this->configure( $conf );
if ( isset( $conf['configCallback'] ) ) {
$this->configCallback = $conf['configCallback'];
}
}
/**
* @param array $conf
* @return void
*/
protected function configure( array $conf ): void {
$this->localDomain = isset( $conf['localDomain'] )
? DatabaseDomain::newFromId( $conf['localDomain'] )
: DatabaseDomain::newUnspecified();
if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
$this->readOnlyReason = $conf['readOnlyReason'];
}
$this->chronologyProtector = $conf['chronologyProtector'] ?? new ChronologyProtector();
$this->srvCache = $conf['srvCache'] ?? new EmptyBagOStuff();
$this->wanCache = $conf['wanCache'] ?? WANObjectCache::newEmpty();
$this->logger = $conf['logger'] ?? new NullLogger();
$this->errorLogger = $conf['errorLogger'] ?? static function ( Throwable $e ) {
trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
};
$this->deprecationLogger = $conf['deprecationLogger'] ?? static function ( $msg ) {
trigger_error( $msg, E_USER_DEPRECATED );
};
$this->profiler = $conf['profiler'] ?? null;
$this->trxProfiler = $conf['trxProfiler'] ?? new TransactionProfiler();
$this->statsd = $conf['statsdDataFactory'] ?? new NullStatsdDataFactory();
$this->csProvider = $conf['criticalSectionProvider'] ?? null;
$this->cliMode = $conf['cliMode'] ?? ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' );
$this->agent = $conf['agent'] ?? '';
$this->defaultGroup = $conf['defaultGroup'] ?? null;
$this->replicationWaitTimeout = $this->cliMode ? 60 : 1;
$this->virtualDomainsMapping = $conf['virtualDomainsMapping'] ?? [];
$this->virtualDomains = $conf['virtualDomains'] ?? [];
static $nextTicket;
$this->ticket = $nextTicket = ( is_int( $nextTicket ) ? $nextTicket++ : mt_rand() );
}
public function destroy() {
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->disable( __METHOD__ );
}
}
/**
* Reload config using the callback passed defined $config['configCallback'].
*
* If the config returned by the callback is different from the existing config,
* this calls reconfigure() on all load balancers, which causes them to invalidate
* any existing connections and re-connect using the new configuration.
*
* Long-running processes should call this from time to time
* (but not too often, because it is somewhat expensive),
* preferably after each batch.
* Maintenance scripts can do that by calling $this->waitForReplication(),
* which calls this method.
*/
public function autoReconfigure(): void {
if ( !$this->configCallback ) {
return;
}
$conf = ( $this->configCallback )();
if ( $conf ) {
$this->reconfigure( $conf );
}
}
/**
* Reconfigure using the given config array.
* Any fields omitted from $conf will be taken from the current config.
*
* If the config changed, this calls reconfigure() on all load balancers,
* which causes them to close all existing connections.
*
* @note This invalidates the current transaction ticket.
*
* @warning This must only be called in top level code such as the execute()
* method of a maintenance script. Any database connection in use when this
* method is called will become defunct.
*
* @since 1.39
*
* @param array $conf A configuration array, using the same structure as
* the one passed to the constructor (see also $wgLBFactoryConf).
*/
public function reconfigure( array $conf ): void {
if ( !$conf ) {
return;
}
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->reconfigure( $conf );
}
}
public function getLocalDomainID(): string {
return $this->localDomain->getId();
}
public function shutdown(
$flags = self::SHUTDOWN_NORMAL,
callable $workCallback = null,
&$cpIndex = null,
&$cpClientId = null
) {
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
if ( ( $flags & self::SHUTDOWN_NO_CHRONPROT ) != self::SHUTDOWN_NO_CHRONPROT ) {
// Remark all of the relevant DB primary positions
foreach ( $this->getLBsForOwner() as $lb ) {
if ( $lb->hasPrimaryConnection() ) {
$this->chronologyProtector->stageSessionPrimaryPos( $lb );
}
}
// Write the positions to the persistent stash
$this->chronologyProtector->persistSessionReplicationPositions( $cpIndex );
$this->logger->debug( __METHOD__ . ': finished ChronologyProtector shutdown' );
}
$cpClientId = $this->chronologyProtector->getClientId();
$this->commitPrimaryChanges( __METHOD__ );
$this->logger->debug( 'LBFactory shutdown completed' );
}
public function getAllLBs() {
foreach ( $this->getLBsForOwner() as $lb ) {
yield $lb;
}
}
/**
* Get all tracked load balancers with the internal "for owner" interface.
*
* @return Generator|ILoadBalancerForOwner[]
*/
abstract protected function getLBsForOwner();
public function flushReplicaSnapshots( $fname = __METHOD__ ) {
if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
$this->logger->warning(
"$fname: transaction round '{$this->trxRoundId}' still running",
[ 'exception' => new RuntimeException() ]
);
}
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->flushReplicaSnapshots( $fname );
}
}
final public function beginPrimaryChanges( $fname = __METHOD__ ) {
$this->assertTransactionRoundStage( self::ROUND_CURSORY );
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
$this->trxRoundStage = self::ROUND_BEGINNING;
if ( $this->trxRoundId !== false ) {
throw new DBTransactionError(
null,
"$fname: transaction round '{$this->trxRoundId}' already started"
);
}
$this->trxRoundId = $fname;
// Set DBO_TRX flags on all appropriate DBs
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->beginPrimaryChanges( $fname );
}
$this->trxRoundStage = self::ROUND_CURSORY;
}
final public function commitPrimaryChanges( $fname = __METHOD__, int $maxWriteDuration = 0 ) {
$this->assertTransactionRoundStage( self::ROUND_CURSORY );
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
$this->trxRoundStage = self::ROUND_COMMITTING;
if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
throw new DBTransactionError(
null,
"$fname: transaction round '{$this->trxRoundId}' still running"
);
}
// Run pre-commit callbacks and suppress post-commit callbacks, aborting on failure
do {
$count = 0; // number of callbacks executed this iteration
foreach ( $this->getLBsForOwner() as $lb ) {
$count += $lb->finalizePrimaryChanges( $fname );
}
} while ( $count > 0 );
$this->trxRoundId = false;
// Perform pre-commit checks, aborting on failure
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->approvePrimaryChanges( $maxWriteDuration, $fname );
}
// Log the DBs and methods involved in multi-DB transactions
$this->logIfMultiDbTransaction();
// Actually perform the commit on all primary DB connections and revert DBO_TRX
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->commitPrimaryChanges( $fname );
}
// Run all post-commit callbacks in a separate step
$this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
$e = $this->executePostTransactionCallbacks();
$this->trxRoundStage = self::ROUND_CURSORY;
// Throw any last post-commit callback error
if ( $e instanceof Exception ) {
throw $e;
}
}
final public function rollbackPrimaryChanges( $fname = __METHOD__ ) {
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
$this->trxRoundStage = self::ROUND_ROLLING_BACK;
$this->trxRoundId = false;
// Actually perform the rollback on all primary DB connections and revert DBO_TRX
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->rollbackPrimaryChanges( $fname );
}
// Run all post-commit callbacks in a separate step
$this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
$this->executePostTransactionCallbacks();
$this->trxRoundStage = self::ROUND_CURSORY;
}
final public function flushPrimarySessions( $fname = __METHOD__ ) {
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
// Release named locks and table locks on all primary DB connections
$this->trxRoundStage = self::ROUND_ROLLBACK_SESSIONS;
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->flushPrimarySessions( $fname );
}
$this->trxRoundStage = self::ROUND_CURSORY;
}
/**
* @return Exception|null
*/
private function executePostTransactionCallbacks() {
$fname = __METHOD__;
// Run all post-commit callbacks until new ones stop getting added
$e = null; // first callback exception
do {
foreach ( $this->getLBsForOwner() as $lb ) {
$ex = $lb->runPrimaryTransactionIdleCallbacks( $fname );
$e = $e ?: $ex;
}
} while ( $this->hasPrimaryChanges() );
// Run all listener callbacks once
foreach ( $this->getLBsForOwner() as $lb ) {
$ex = $lb->runPrimaryTransactionListenerCallbacks( $fname );
$e = $e ?: $ex;
}
return $e;
}
public function hasTransactionRound() {
return ( $this->trxRoundId !== false );
}
public function isReadyForRoundOperations() {
return ( $this->trxRoundStage === self::ROUND_CURSORY );
}
/**
* Log query info if multi DB transactions are going to be committed now
*/
private function logIfMultiDbTransaction() {
$callersByDB = [];
foreach ( $this->getLBsForOwner() as $lb ) {
$primaryName = $lb->getServerName( ServerInfo::WRITER_INDEX );
$callers = $lb->pendingPrimaryChangeCallers();
if ( $callers ) {
$callersByDB[$primaryName] = $callers;
}
}
if ( count( $callersByDB ) >= 2 ) {
$dbs = implode( ', ', array_keys( $callersByDB ) );
$msg = "Multi-DB transaction [{$dbs}]:\n";
foreach ( $callersByDB as $db => $callers ) {
$msg .= "$db: " . implode( '; ', $callers ) . "\n";
}
$this->logger->info( $msg );
}
}
public function hasPrimaryChanges() {
foreach ( $this->getLBsForOwner() as $lb ) {
if ( $lb->hasPrimaryChanges() ) {
return true;
}
}
return false;
}
public function laggedReplicaUsed() {
foreach ( $this->getLBsForOwner() as $lb ) {
if ( $lb->laggedReplicaUsed() ) {
return true;
}
}
return false;
}
public function hasOrMadeRecentPrimaryChanges( $age = null ) {
foreach ( $this->getLBsForOwner() as $lb ) {
if ( $lb->hasOrMadeRecentPrimaryChanges( $age ) ) {
return true;
}
}
return false;
}
public function waitForReplication( array $opts = [] ) {
$opts += [
'timeout' => $this->replicationWaitTimeout,
'ifWritesSince' => null
];
$lbs = [];
foreach ( $this->getLBsForOwner() as $lb ) {
$lbs[] = $lb;
}
// Get all the primary DB positions of applicable DBs right now.
// This can be faster since waiting on one cluster reduces the
// time needed to wait on the next clusters.
$primaryPositions = array_fill( 0, count( $lbs ), false );
foreach ( $lbs as $i => $lb ) {
if (
// No writes to wait on getting replicated
!$lb->hasPrimaryConnection() ||
// No replication; avoid getPrimaryPos() permissions errors (T29975)
!$lb->hasStreamingReplicaServers() ||
// No writes since the last replication wait
(
$opts['ifWritesSince'] &&
$lb->lastPrimaryChangeTimestamp() < $opts['ifWritesSince']
)
) {
continue; // no need to wait
}
$primaryPositions[$i] = $lb->getPrimaryPos();
}
// Run any listener callbacks *after* getting the DB positions. The more
// time spent in the callbacks, the less time is spent in waitForAll().
foreach ( $this->replicationWaitCallbacks as $callback ) {
$callback();
}
$failed = [];
foreach ( $lbs as $i => $lb ) {
if ( $primaryPositions[$i] ) {
// The RDBMS may not support getPrimaryPos()
if ( !$lb->waitForAll( $primaryPositions[$i], $opts['timeout'] ) ) {
$failed[] = $lb->getServerName( ServerInfo::WRITER_INDEX );
}
}
}
return !$failed;
}
public function setWaitForReplicationListener( $name, callable $callback = null ) {
if ( $callback ) {
$this->replicationWaitCallbacks[$name] = $callback;
} else {
unset( $this->replicationWaitCallbacks[$name] );
}
}
public function getEmptyTransactionTicket( $fname ) {
if ( $this->hasPrimaryChanges() ) {
$this->logger->error(
__METHOD__ . ": $fname does not have outer scope",
[ 'exception' => new RuntimeException() ]
);
return null;
}
return $this->ticket;
}
public function getPrimaryDatabase( $domain = false ): IDatabase {
return $this->getMappedDatabase( DB_PRIMARY, [], $domain );
}
public function getReplicaDatabase( $domain = false, $group = null ): IReadableDatabase {
if ( $group === null ) {
$groups = [];
} else {
$groups = [ $group ];
}
return $this->getMappedDatabase( DB_REPLICA, $groups, $domain );
}
public function getLoadBalancer( $domain = false ): ILoadBalancer {
if ( $domain !== false && in_array( $domain, $this->virtualDomains ) ) {
if ( isset( $this->virtualDomainsMapping[$domain] ) ) {
$config = $this->virtualDomainsMapping[$domain];
if ( isset( $config['cluster'] ) ) {
return $this->getExternalLB( $config['cluster'] );
}
$domain = $config['db'];
} else {
// It's not configured, assume local db.
$domain = false;
}
}
return $this->getMainLB( $domain );
}
/**
* Helper for getPrimaryDatabase and getReplicaDatabase() providing virtual
* domain mapping.
*
* @param int $index
* @param array $groups
* @param string|false $domain
* @return IDatabase
*/
private function getMappedDatabase( $index, $groups, $domain ) {
if ( $domain !== false && in_array( $domain, $this->virtualDomains ) ) {
$dbDomain = $this->virtualDomainsMapping[$domain]['db'] ?? false;
} else {
$dbDomain = $domain;
}
return $this->getLoadBalancer( $domain )->getConnection( $index, $groups, $dbDomain );
}
final public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
if ( $ticket !== $this->ticket ) {
$this->logger->error(
__METHOD__ . ": $fname does not have outer scope ($ticket vs {$this->ticket})",
[ 'exception' => new RuntimeException() ]
);
return false;
}
// The transaction owner and any caller with the empty transaction ticket can commit
// so that getEmptyTransactionTicket() callers don't risk seeing DBTransactionError.
if ( $this->trxRoundId !== false && $fname !== $this->trxRoundId ) {
$this->logger->info( "$fname: committing on behalf of {$this->trxRoundId}" );
$fnameEffective = $this->trxRoundId;
} else {
$fnameEffective = $fname;
}
$this->commitPrimaryChanges( $fnameEffective );
$waitSucceeded = $this->waitForReplication( $opts );
// If a nested caller committed on behalf of $fname, start another empty $fname
// transaction, leaving the caller with the same empty transaction state as before.
if ( $fnameEffective !== $fname ) {
$this->beginPrimaryChanges( $fnameEffective );
}
return $waitSucceeded;
}
public function disableChronologyProtection() {
$this->chronologyProtector->setEnabled( false );
}
/**
* Get parameters to ILoadBalancer::__construct()
*
* @return array
*/
final protected function baseLoadBalancerParams() {
if ( $this->trxRoundStage === self::ROUND_COMMIT_CALLBACKS ) {
$initStage = ILoadBalancerForOwner::STAGE_POSTCOMMIT_CALLBACKS;
} elseif ( $this->trxRoundStage === self::ROUND_ROLLBACK_CALLBACKS ) {
$initStage = ILoadBalancerForOwner::STAGE_POSTROLLBACK_CALLBACKS;
} else {
$initStage = null;
}
return [
'localDomain' => $this->localDomain,
'readOnlyReason' => $this->readOnlyReason,
'srvCache' => $this->srvCache,
'wanCache' => $this->wanCache,
'profiler' => $this->profiler,
'trxProfiler' => $this->trxProfiler,
'logger' => $this->logger,
'errorLogger' => $this->errorLogger,
'deprecationLogger' => $this->deprecationLogger,
'statsdDataFactory' => $this->statsd,
'cliMode' => $this->cliMode,
'agent' => $this->agent,
'defaultGroup' => $this->defaultGroup,
'chronologyProtector' => $this->chronologyProtector,
'roundStage' => $initStage,
'criticalSectionProvider' => $this->csProvider
];
}
/**
* @param ILoadBalancerForOwner $lb
*/
protected function initLoadBalancer( ILoadBalancerForOwner $lb ) {
if ( $this->trxRoundId !== false ) {
$lb->beginPrimaryChanges( $this->trxRoundId ); // set DBO_TRX
}
$lb->setTableAliases( $this->tableAliases );
$lb->setIndexAliases( $this->indexAliases );
$lb->setDomainAliases( $this->domainAliases );
}
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 getTransactionProfiler(): TransactionProfiler {
return $this->trxProfiler;
}
public function setLocalDomainPrefix( $prefix ) {
$this->localDomain = new DatabaseDomain(
$this->localDomain->getDatabase(),
$this->localDomain->getSchema(),
$prefix
);
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->setLocalDomainPrefix( $prefix );
}
}
public function redefineLocalDomain( $domain ) {
$this->closeAll( __METHOD__ );
$this->localDomain = DatabaseDomain::newFromId( $domain );
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->redefineLocalDomain( $this->localDomain );
}
}
public function closeAll( $fname = __METHOD__ ) {
/** @noinspection PhpUnusedLocalVariableInspection */
$scope = ScopedCallback::newScopedIgnoreUserAbort();
foreach ( $this->getLBsForOwner() as $lb ) {
$lb->closeAll( $fname );
}
}
public function setAgentName( $agent ) {
$this->agent = $agent;
}
public function hasStreamingReplicaServers() {
foreach ( $this->getLBsForOwner() as $lb ) {
if ( $lb->hasStreamingReplicaServers() ) {
return true;
}
}
return false;
}
public function setDefaultReplicationWaitTimeout( $seconds ) {
$old = $this->replicationWaitTimeout;
$this->replicationWaitTimeout = max( 1, (int)$seconds );
return $old;
}
/**
* @param string $stage
*/
private function assertTransactionRoundStage( $stage ) {
if ( $this->trxRoundStage !== $stage ) {
throw new DBTransactionError(
null,
"Transaction round stage must be '$stage' (not '{$this->trxRoundStage}')"
);
}
}
}