includes/libs/rdbms/lbfactory/LBFactory.php

   1 <?php
   2 /**
   3  * Generator and manager of database load balancing objects
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 namespace Wikimedia\Rdbms;
  25
  26 use Psr\Log\LoggerInterface;
  27 use Wikimedia\ScopedCallback;
  28 use BagOStuff;
  29 use EmptyBagOStuff;
  30 use WANObjectCache;
  31 use Exception;
  32 use RuntimeException;
  33 use LogicException;
  34
  35 /**
  36  * An interface for generating database load balancers
  37  * @ingroup Database
  38  */
  39 abstract class LBFactory implements ILBFactory {
  40         /** @var ChronologyProtector */
  41         private $chronProt;
  42         /** @var object|string Class name or object With profileIn/profileOut methods */
  43         private $profiler;
  44         /** @var TransactionProfiler */
  45         private $trxProfiler;
  46         /** @var LoggerInterface */
  47         private $replLogger;
  48         /** @var LoggerInterface */
  49         private $connLogger;
  50         /** @var LoggerInterface */
  51         private $queryLogger;
  52         /** @var LoggerInterface */
  53         private $perfLogger;
  54         /** @var callable Error logger */
  55         private $errorLogger;
  56         /** @var callable Deprecation logger */
  57         private $deprecationLogger;
  58
  59         /** @var BagOStuff */
  60         protected $srvCache;
  61         /** @var BagOStuff */
  62         protected $memStash;
  63         /** @var WANObjectCache */
  64         protected $wanCache;
  65
  66         /** @var DatabaseDomain Local domain */
  67         protected $localDomain;
  68
  69         /** @var string Local hostname of the app server */
  70         private $hostname;
  71         /** @var array Web request information about the client */
  72         private $requestInfo;
  73         /** @var bool Whether this PHP instance is for a CLI script */
  74         private $cliMode;
  75         /** @var string Agent name for query profiling */
  76         private $agent;
  77
  78         /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
  79         private $tableAliases = [];
  80         /** @var string[] Map of (index alias => index) */
  81         private $indexAliases = [];
  82         /** @var callable[] */
  83         private $replicationWaitCallbacks = [];
  84
  85         /** @var mixed */
  86         private $ticket;
  87         /** @var string|bool String if a requested DBO_TRX transaction round is active */
  88         private $trxRoundId = false;
  89         /** @var string One of the ROUND_* class constants */
  90         private $trxRoundStage = self::ROUND_CURSORY;
  91
  92         /** @var string|bool Reason all LBs are read-only or false if not */
  93         protected $readOnlyReason = false;
  94
  95         /** @var string|null */
  96         private $defaultGroup = null;
  97
  98         const ROUND_CURSORY = 'cursory';
  99         const ROUND_BEGINNING = 'within-begin';
 100         const ROUND_COMMITTING = 'within-commit';
 101         const ROUND_ROLLING_BACK = 'within-rollback';
 102         const ROUND_COMMIT_CALLBACKS = 'within-commit-callbacks';
 103         const ROUND_ROLLBACK_CALLBACKS = 'within-rollback-callbacks';
 104
 105         private static $loggerFields =
 106                 [ 'replLogger', 'connLogger', 'queryLogger', 'perfLogger' ];
 107
 108         public function __construct( array $conf ) {
 109                 $this->localDomain = isset( $conf['localDomain'] )
 110                         ? DatabaseDomain::newFromId( $conf['localDomain'] )
 111                         : DatabaseDomain::newUnspecified();
 112
 113                 if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
 114                         $this->readOnlyReason = $conf['readOnlyReason'];
 115                 }
 116
 117                 $this->srvCache = $conf['srvCache'] ?? new EmptyBagOStuff();
 118                 $this->memStash = $conf['memStash'] ?? new EmptyBagOStuff();
 119                 $this->wanCache = $conf['wanCache'] ?? WANObjectCache::newEmpty();
 120
 121                 foreach ( self::$loggerFields as $key ) {
 122                         $this->$key = $conf[$key] ?? new \Psr\Log\NullLogger();
 123                 }
 124                 $this->errorLogger = $conf['errorLogger'] ?? function ( Exception $e ) {
 125                         trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
 126                 };
 127                 $this->deprecationLogger = $conf['deprecationLogger'] ?? function ( $msg ) {
 128                         trigger_error( $msg, E_USER_DEPRECATED );
 129                 };
 130
 131                 $this->profiler = $conf['profiler'] ?? null;
 132                 $this->trxProfiler = $conf['trxProfiler'] ?? new TransactionProfiler();
 133
 134                 $this->requestInfo = [
 135                         'IPAddress' => $_SERVER[ 'REMOTE_ADDR' ] ?? '',
 136                         'UserAgent' => $_SERVER['HTTP_USER_AGENT'] ?? '',
 137                         // Headers application can inject via LBFactory::setRequestInfo()
 138                         'ChronologyProtection' => null,
 139                         'ChronologyClientId' => null, // prior $cpClientId value from LBFactory::shutdown()
 140                         'ChronologyPositionIndex' => null // prior $cpIndex value from LBFactory::shutdown()
 141                 ];
 142
 143                 $this->cliMode = $conf['cliMode'] ?? ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' );
 144                 $this->hostname = $conf['hostname'] ?? gethostname();
 145                 $this->agent = $conf['agent'] ?? '';
 146                 $this->defaultGroup = $conf['defaultGroup'] ?? null;
 147
 148                 $this->ticket = mt_rand();
 149         }
 150
 151         public function destroy() {
 152                 $this->shutdown( self::SHUTDOWN_NO_CHRONPROT );
 153                 $this->forEachLBCallMethod( 'disable' );
 154         }
 155
 156         public function getLocalDomainID() {
 157                 return $this->localDomain->getId();
 158         }
 159
 160         public function resolveDomainID( $domain ) {
 161                 return ( $domain !== false ) ? (string)$domain : $this->getLocalDomainID();
 162         }
 163
 164         public function shutdown(
 165                 $mode = self::SHUTDOWN_CHRONPROT_SYNC,
 166                 callable $workCallback = null,
 167                 &$cpIndex = null,
 168                 &$cpClientId = null
 169         ) {
 170                 $chronProt = $this->getChronologyProtector();
 171                 if ( $mode === self::SHUTDOWN_CHRONPROT_SYNC ) {
 172                         $this->shutdownChronologyProtector( $chronProt, $workCallback, 'sync', $cpIndex );
 173                 } elseif ( $mode === self::SHUTDOWN_CHRONPROT_ASYNC ) {
 174                         $this->shutdownChronologyProtector( $chronProt, null, 'async', $cpIndex );
 175                 }
 176
 177                 $cpClientId = $chronProt->getClientId();
 178
 179                 $this->commitMasterChanges( __METHOD__ ); // sanity
 180         }
 181
 182         /**
 183          * @see ILBFactory::newMainLB()
 184          * @param bool $domain
 185          * @return ILoadBalancer
 186          */
 187         abstract public function newMainLB( $domain = false );
 188
 189         /**
 190          * @see ILBFactory::getMainLB()
 191          * @param bool $domain
 192          * @return ILoadBalancer
 193          */
 194         abstract public function getMainLB( $domain = false );
 195
 196         /**
 197          * @see ILBFactory::newExternalLB()
 198          * @param string $cluster
 199          * @return ILoadBalancer
 200          */
 201         abstract public function newExternalLB( $cluster );
 202
 203         /**
 204          * @see ILBFactory::getExternalLB()
 205          * @param string $cluster
 206          * @return ILoadBalancer
 207          */
 208         abstract public function getExternalLB( $cluster );
 209
 210         /**
 211          * Call a method of each tracked load balancer
 212          *
 213          * @param string $methodName
 214          * @param array $args
 215          */
 216         protected function forEachLBCallMethod( $methodName, array $args = [] ) {
 217                 $this->forEachLB(
 218                         function ( ILoadBalancer $loadBalancer, $methodName, array $args ) {
 219                                 $loadBalancer->$methodName( ...$args );
 220                         },
 221                         [ $methodName, $args ]
 222                 );
 223         }
 224
 225         public function flushReplicaSnapshots( $fname = __METHOD__ ) {
 226                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 227         }
 228
 229         final public function commitAll( $fname = __METHOD__, array $options = [] ) {
 230                 $this->commitMasterChanges( $fname, $options );
 231                 $this->forEachLBCallMethod( 'flushMasterSnapshots', [ $fname ] );
 232                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 233         }
 234
 235         final public function beginMasterChanges( $fname = __METHOD__ ) {
 236                 $this->assertTransactionRoundStage( self::ROUND_CURSORY );
 237                 $this->trxRoundStage = self::ROUND_BEGINNING;
 238                 if ( $this->trxRoundId !== false ) {
 239                         throw new DBTransactionError(
 240                                 null,
 241                                 "$fname: transaction round '{$this->trxRoundId}' already started."
 242                         );
 243                 }
 244                 $this->trxRoundId = $fname;
 245                 // Set DBO_TRX flags on all appropriate DBs
 246                 $this->forEachLBCallMethod( 'beginMasterChanges', [ $fname ] );
 247                 $this->trxRoundStage = self::ROUND_CURSORY;
 248         }
 249
 250         final public function commitMasterChanges( $fname = __METHOD__, array $options = [] ) {
 251                 $this->assertTransactionRoundStage( self::ROUND_CURSORY );
 252                 $this->trxRoundStage = self::ROUND_COMMITTING;
 253                 if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
 254                         throw new DBTransactionError(
 255                                 null,
 256                                 "$fname: transaction round '{$this->trxRoundId}' still running."
 257                         );
 258                 }
 259                 /** @noinspection PhpUnusedLocalVariableInspection */
 260                 $scope = $this->getScopedPHPBehaviorForCommit(); // try to ignore client aborts
 261                 // Run pre-commit callbacks and suppress post-commit callbacks, aborting on failure
 262                 do {
 263                         $count = 0; // number of callbacks executed this iteration
 264                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$count ) {
 265                                 $count += $lb->finalizeMasterChanges();
 266                         } );
 267                 } while ( $count > 0 );
 268                 $this->trxRoundId = false;
 269                 // Perform pre-commit checks, aborting on failure
 270                 $this->forEachLBCallMethod( 'approveMasterChanges', [ $options ] );
 271                 // Log the DBs and methods involved in multi-DB transactions
 272                 $this->logIfMultiDbTransaction();
 273                 // Actually perform the commit on all master DB connections and revert DBO_TRX
 274                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 275                 // Run all post-commit callbacks in a separate step
 276                 $this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
 277                 $e = $this->executePostTransactionCallbacks();
 278                 $this->trxRoundStage = self::ROUND_CURSORY;
 279                 // Throw any last post-commit callback error
 280                 if ( $e instanceof Exception ) {
 281                         throw $e;
 282                 }
 283         }
 284
 285         final public function rollbackMasterChanges( $fname = __METHOD__ ) {
 286                 $this->trxRoundStage = self::ROUND_ROLLING_BACK;
 287                 $this->trxRoundId = false;
 288                 // Actually perform the rollback on all master DB connections and revert DBO_TRX
 289                 $this->forEachLBCallMethod( 'rollbackMasterChanges', [ $fname ] );
 290                 // Run all post-commit callbacks in a separate step
 291                 $this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
 292                 $this->executePostTransactionCallbacks();
 293                 $this->trxRoundStage = self::ROUND_CURSORY;
 294         }
 295
 296         /**
 297          * @return Exception|null
 298          */
 299         private function executePostTransactionCallbacks() {
 300                 // Run all post-commit callbacks until new ones stop getting added
 301                 $e = null; // first callback exception
 302                 do {
 303                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 304                                 $ex = $lb->runMasterTransactionIdleCallbacks();
 305                                 $e = $e ?: $ex;
 306                         } );
 307                 } while ( $this->hasMasterChanges() );
 308                 // Run all listener callbacks once
 309                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 310                         $ex = $lb->runMasterTransactionListenerCallbacks();
 311                         $e = $e ?: $ex;
 312                 } );
 313
 314                 return $e;
 315         }
 316
 317         public function hasTransactionRound() {
 318                 return ( $this->trxRoundId !== false );
 319         }
 320
 321         public function isReadyForRoundOperations() {
 322                 return ( $this->trxRoundStage === self::ROUND_CURSORY );
 323         }
 324
 325         /**
 326          * Log query info if multi DB transactions are going to be committed now
 327          */
 328         private function logIfMultiDbTransaction() {
 329                 $callersByDB = [];
 330                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$callersByDB ) {
 331                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 332                         $callers = $lb->pendingMasterChangeCallers();
 333                         if ( $callers ) {
 334                                 $callersByDB[$masterName] = $callers;
 335                         }
 336                 } );
 337
 338                 if ( count( $callersByDB ) >= 2 ) {
 339                         $dbs = implode( ', ', array_keys( $callersByDB ) );
 340                         $msg = "Multi-DB transaction [{$dbs}]:\n";
 341                         foreach ( $callersByDB as $db => $callers ) {
 342                                 $msg .= "$db: " . implode( '; ', $callers ) . "\n";
 343                         }
 344                         $this->queryLogger->info( $msg );
 345                 }
 346         }
 347
 348         public function hasMasterChanges() {
 349                 $ret = false;
 350                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 351                         $ret = $ret || $lb->hasMasterChanges();
 352                 } );
 353
 354                 return $ret;
 355         }
 356
 357         public function laggedReplicaUsed() {
 358                 $ret = false;
 359                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 360                         $ret = $ret || $lb->laggedReplicaUsed();
 361                 } );
 362
 363                 return $ret;
 364         }
 365
 366         public function hasOrMadeRecentMasterChanges( $age = null ) {
 367                 $ret = false;
 368                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $age, &$ret ) {
 369                         $ret = $ret || $lb->hasOrMadeRecentMasterChanges( $age );
 370                 } );
 371                 return $ret;
 372         }
 373
 374         public function waitForReplication( array $opts = [] ) {
 375                 $opts += [
 376                         'domain' => false,
 377                         'cluster' => false,
 378                         'timeout' => $this->cliMode ? 60 : 10,
 379                         'ifWritesSince' => null
 380                 ];
 381
 382                 if ( $opts['domain'] === false && isset( $opts['wiki'] ) ) {
 383                         $opts['domain'] = $opts['wiki']; // b/c
 384                 }
 385
 386                 // Figure out which clusters need to be checked
 387                 /** @var ILoadBalancer[] $lbs */
 388                 $lbs = [];
 389                 if ( $opts['cluster'] !== false ) {
 390                         $lbs[] = $this->getExternalLB( $opts['cluster'] );
 391                 } elseif ( $opts['domain'] !== false ) {
 392                         $lbs[] = $this->getMainLB( $opts['domain'] );
 393                 } else {
 394                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$lbs ) {
 395                                 $lbs[] = $lb;
 396                         } );
 397                         if ( !$lbs ) {
 398                                 return; // nothing actually used
 399                         }
 400                 }
 401
 402                 // Get all the master positions of applicable DBs right now.
 403                 // This can be faster since waiting on one cluster reduces the
 404                 // time needed to wait on the next clusters.
 405                 $masterPositions = array_fill( 0, count( $lbs ), false );
 406                 foreach ( $lbs as $i => $lb ) {
 407                         if ( $lb->getServerCount() <= 1 ) {
 408                                 // T29975 - Don't try to wait for replica DBs if there are none
 409                                 // Prevents permission error when getting master position
 410                                 continue;
 411                         } elseif ( $opts['ifWritesSince']
 412                                 && $lb->lastMasterChangeTimestamp() < $opts['ifWritesSince']
 413                         ) {
 414                                 continue; // no writes since the last wait
 415                         }
 416                         $masterPositions[$i] = $lb->getMasterPos();
 417                 }
 418
 419                 // Run any listener callbacks *after* getting the DB positions. The more
 420                 // time spent in the callbacks, the less time is spent in waitForAll().
 421                 foreach ( $this->replicationWaitCallbacks as $callback ) {
 422                         $callback();
 423                 }
 424
 425                 $failed = [];
 426                 foreach ( $lbs as $i => $lb ) {
 427                         if ( $masterPositions[$i] ) {
 428                                 // The RDBMS may not support getMasterPos()
 429                                 if ( !$lb->waitForAll( $masterPositions[$i], $opts['timeout'] ) ) {
 430                                         $failed[] = $lb->getServerName( $lb->getWriterIndex() );
 431                                 }
 432                         }
 433                 }
 434
 435                 if ( $failed ) {
 436                         throw new DBReplicationWaitError(
 437                                 null,
 438                                 "Could not wait for replica DBs to catch up to " .
 439                                 implode( ', ', $failed )
 440                         );
 441                 }
 442         }
 443
 444         public function setWaitForReplicationListener( $name, callable $callback = null ) {
 445                 if ( $callback ) {
 446                         $this->replicationWaitCallbacks[$name] = $callback;
 447                 } else {
 448                         unset( $this->replicationWaitCallbacks[$name] );
 449                 }
 450         }
 451
 452         public function getEmptyTransactionTicket( $fname ) {
 453                 if ( $this->hasMasterChanges() ) {
 454                         $this->queryLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 455                                 ( new RuntimeException() )->getTraceAsString() );
 456
 457                         return null;
 458                 }
 459
 460                 return $this->ticket;
 461         }
 462
 463         final public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
 464                 if ( $ticket !== $this->ticket ) {
 465                         $this->perfLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 466                                 ( new RuntimeException() )->getTraceAsString() );
 467
 468                         return;
 469                 }
 470
 471                 // The transaction owner and any caller with the empty transaction ticket can commit
 472                 // so that getEmptyTransactionTicket() callers don't risk seeing DBTransactionError.
 473                 if ( $this->trxRoundId !== false && $fname !== $this->trxRoundId ) {
 474                         $this->queryLogger->info( "$fname: committing on behalf of {$this->trxRoundId}." );
 475                         $fnameEffective = $this->trxRoundId;
 476                 } else {
 477                         $fnameEffective = $fname;
 478                 }
 479
 480                 $this->commitMasterChanges( $fnameEffective );
 481                 $this->waitForReplication( $opts );
 482                 // If a nested caller committed on behalf of $fname, start another empty $fname
 483                 // transaction, leaving the caller with the same empty transaction state as before.
 484                 if ( $fnameEffective !== $fname ) {
 485                         $this->beginMasterChanges( $fnameEffective );
 486                 }
 487         }
 488
 489         public function getChronologyProtectorTouched( $dbName ) {
 490                 return $this->getChronologyProtector()->getTouched( $dbName );
 491         }
 492
 493         public function disableChronologyProtection() {
 494                 $this->getChronologyProtector()->setEnabled( false );
 495         }
 496
 497         /**
 498          * @return ChronologyProtector
 499          */
 500         protected function getChronologyProtector() {
 501                 if ( $this->chronProt ) {
 502                         return $this->chronProt;
 503                 }
 504
 505                 $this->chronProt = new ChronologyProtector(
 506                         $this->memStash,
 507                         [
 508                                 'ip' => $this->requestInfo['IPAddress'],
 509                                 'agent' => $this->requestInfo['UserAgent'],
 510                                 'clientId' => $this->requestInfo['ChronologyClientId']
 511                         ],
 512                         $this->requestInfo['ChronologyPositionIndex']
 513                 );
 514                 $this->chronProt->setLogger( $this->replLogger );
 515
 516                 if ( $this->cliMode ) {
 517                         $this->chronProt->setEnabled( false );
 518                 } elseif ( $this->requestInfo['ChronologyProtection'] === 'false' ) {
 519                         // Request opted out of using position wait logic. This is useful for requests
 520                         // done by the job queue or background ETL that do not have a meaningful session.
 521                         $this->chronProt->setWaitEnabled( false );
 522                 } elseif ( $this->memStash instanceof EmptyBagOStuff ) {
 523                         // No where to store any DB positions and wait for them to appear
 524                         $this->chronProt->setEnabled( false );
 525                         $this->replLogger->info( 'Cannot use ChronologyProtector with EmptyBagOStuff.' );
 526                 }
 527
 528                 $this->replLogger->debug( __METHOD__ . ': using request info ' .
 529                         json_encode( $this->requestInfo, JSON_PRETTY_PRINT ) );
 530
 531                 return $this->chronProt;
 532         }
 533
 534         /**
 535          * Get and record all of the staged DB positions into persistent memory storage
 536          *
 537          * @param ChronologyProtector $cp
 538          * @param callable|null $workCallback Work to do instead of waiting on syncing positions
 539          * @param string $mode One of (sync, async); whether to wait on remote datacenters
 540          * @param int|null &$cpIndex DB position key write counter; incremented on update
 541          */
 542         protected function shutdownChronologyProtector(
 543                 ChronologyProtector $cp, $workCallback, $mode, &$cpIndex = null
 544         ) {
 545                 // Record all the master positions needed
 546                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $cp ) {
 547                         $cp->shutdownLB( $lb );
 548                 } );
 549                 // Write them to the persistent stash. Try to do something useful by running $work
 550                 // while ChronologyProtector waits for the stash write to replicate to all DCs.
 551                 $unsavedPositions = $cp->shutdown( $workCallback, $mode, $cpIndex );
 552                 if ( $unsavedPositions && $workCallback ) {
 553                         // Invoke callback in case it did not cache the result yet
 554                         $workCallback(); // work now to block for less time in waitForAll()
 555                 }
 556                 // If the positions failed to write to the stash, at least wait on local datacenter
 557                 // replica DBs to catch up before responding. Even if there are several DCs, this increases
 558                 // the chance that the user will see their own changes immediately afterwards. As long
 559                 // as the sticky DC cookie applies (same domain), this is not even an issue.
 560                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $unsavedPositions ) {
 561                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 562                         if ( isset( $unsavedPositions[$masterName] ) ) {
 563                                 $lb->waitForAll( $unsavedPositions[$masterName] );
 564                         }
 565                 } );
 566         }
 567
 568         /**
 569          * Base parameters to ILoadBalancer::__construct()
 570          * @return array
 571          */
 572         final protected function baseLoadBalancerParams() {
 573                 if ( $this->trxRoundStage === self::ROUND_COMMIT_CALLBACKS ) {
 574                         $initStage = ILoadBalancer::STAGE_POSTCOMMIT_CALLBACKS;
 575                 } elseif ( $this->trxRoundStage === self::ROUND_ROLLBACK_CALLBACKS ) {
 576                         $initStage = ILoadBalancer::STAGE_POSTROLLBACK_CALLBACKS;
 577                 } else {
 578                         $initStage = null;
 579                 }
 580
 581                 return [
 582                         'localDomain' => $this->localDomain,
 583                         'readOnlyReason' => $this->readOnlyReason,
 584                         'srvCache' => $this->srvCache,
 585                         'wanCache' => $this->wanCache,
 586                         'profiler' => $this->profiler,
 587                         'trxProfiler' => $this->trxProfiler,
 588                         'queryLogger' => $this->queryLogger,
 589                         'connLogger' => $this->connLogger,
 590                         'replLogger' => $this->replLogger,
 591                         'errorLogger' => $this->errorLogger,
 592                         'deprecationLogger' => $this->deprecationLogger,
 593                         'hostname' => $this->hostname,
 594                         'cliMode' => $this->cliMode,
 595                         'agent' => $this->agent,
 596                         'defaultGroup' => $this->defaultGroup,
 597                         'chronologyCallback' => function ( ILoadBalancer $lb ) {
 598                                 // Defer ChronologyProtector construction in case setRequestInfo() ends up
 599                                 // being called later (but before the first connection attempt) (T192611)
 600                                 $this->getChronologyProtector()->initLB( $lb );
 601                         },
 602                         'roundStage' => $initStage
 603                 ];
 604         }
 605
 606         /**
 607          * @param ILoadBalancer $lb
 608          */
 609         protected function initLoadBalancer( ILoadBalancer $lb ) {
 610                 if ( $this->trxRoundId !== false ) {
 611                         $lb->beginMasterChanges( $this->trxRoundId ); // set DBO_TRX
 612                 }
 613
 614                 $lb->setTableAliases( $this->tableAliases );
 615                 $lb->setIndexAliases( $this->indexAliases );
 616         }
 617
 618         public function setTableAliases( array $aliases ) {
 619                 $this->tableAliases = $aliases;
 620         }
 621
 622         public function setIndexAliases( array $aliases ) {
 623                 $this->indexAliases = $aliases;
 624         }
 625
 626         public function setDomainPrefix( $prefix ) {
 627                 $this->localDomain = new DatabaseDomain(
 628                         $this->localDomain->getDatabase(),
 629                         null,
 630                         $prefix
 631                 );
 632
 633                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $prefix ) {
 634                         $lb->setDomainPrefix( $prefix );
 635                 } );
 636         }
 637
 638         public function closeAll() {
 639                 $this->forEachLBCallMethod( 'closeAll', [] );
 640         }
 641
 642         public function setAgentName( $agent ) {
 643                 $this->agent = $agent;
 644         }
 645
 646         public function appendShutdownCPIndexAsQuery( $url, $index ) {
 647                 $usedCluster = 0;
 648                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$usedCluster ) {
 649                         $usedCluster |= ( $lb->getServerCount() > 1 );
 650                 } );
 651
 652                 if ( !$usedCluster ) {
 653                         return $url; // no master/replica clusters touched
 654                 }
 655
 656                 return strpos( $url, '?' ) === false ? "$url?cpPosIndex=$index" : "$url&cpPosIndex=$index";
 657         }
 658
 659         /**
 660          * @param int $index Write index
 661          * @param int $time UNIX timestamp; can be used to detect stale cookies (T190082)
 662          * @param string $clientId Agent ID hash from ILBFactory::shutdown()
 663          * @return string Timestamp-qualified write index of the form "<index>@<timestamp>#<hash>"
 664          * @since 1.32
 665          */
 666         public static function makeCookieValueFromCPIndex( $index, $time, $clientId ) {
 667                 return "$index@$time#$clientId";
 668         }
 669
 670         /**
 671          * @param string $value Possible result of LBFactory::makeCookieValueFromCPIndex()
 672          * @param int $minTimestamp Lowest UNIX timestamp that a non-expired value can have
 673          * @return array (index: int or null, clientId: string or null)
 674          * @since 1.32
 675          */
 676         public static function getCPInfoFromCookieValue( $value, $minTimestamp ) {
 677                 static $placeholder = [ 'index' => null, 'clientId' => null ];
 678
 679                 if ( !preg_match( '/^(\d+)@(\d+)#([0-9a-f]{32})$/', $value, $m ) ) {
 680                         return $placeholder; // invalid
 681                 }
 682
 683                 $index = (int)$m[1];
 684                 if ( $index <= 0 ) {
 685                         return $placeholder; // invalid
 686                 } elseif ( isset( $m[2] ) && $m[2] !== '' && (int)$m[2] < $minTimestamp ) {
 687                         return $placeholder; // expired
 688                 }
 689
 690                 $clientId = ( isset( $m[3] ) && $m[3] !== '' ) ? $m[3] : null;
 691
 692                 return [ 'index' => $index, 'clientId' => $clientId ];
 693         }
 694
 695         public function setRequestInfo( array $info ) {
 696                 if ( $this->chronProt ) {
 697                         throw new LogicException( 'ChronologyProtector already initialized.' );
 698                 }
 699
 700                 $this->requestInfo = $info + $this->requestInfo;
 701         }
 702
 703         /**
 704          * @param string $stage
 705          */
 706         private function assertTransactionRoundStage( $stage ) {
 707                 if ( $this->trxRoundStage !== $stage ) {
 708                         throw new DBTransactionError(
 709                                 null,
 710                                 "Transaction round stage must be '$stage' (not '{$this->trxRoundStage}')"
 711                         );
 712                 }
 713         }
 714
 715         /**
 716          * Make PHP ignore user aborts/disconnects until the returned
 717          * value leaves scope. This returns null and does nothing in CLI mode.
 718          *
 719          * @return ScopedCallback|null
 720          */
 721         final protected function getScopedPHPBehaviorForCommit() {
 722                 if ( PHP_SAPI != 'cli' ) { // https://bugs.php.net/bug.php?id=47540
 723                         $old = ignore_user_abort( true ); // avoid half-finished operations
 724                         return new ScopedCallback( function () use ( $old ) {
 725                                 ignore_user_abort( $old );
 726                         } );
 727                 }
 728
 729                 return null;
 730         }
 731
 732         function __destruct() {
 733                 $this->destroy();
 734         }
 735 }
 736
 737 /**
 738  * @deprecated since 1.29
 739  */
 740 class_alias( LBFactory::class, 'LBFactory' );