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         /** @var int|null */
  99         protected $maxLag;
 100
 101         const ROUND_CURSORY = 'cursory';
 102         const ROUND_BEGINNING = 'within-begin';
 103         const ROUND_COMMITTING = 'within-commit';
 104         const ROUND_ROLLING_BACK = 'within-rollback';
 105         const ROUND_COMMIT_CALLBACKS = 'within-commit-callbacks';
 106         const ROUND_ROLLBACK_CALLBACKS = 'within-rollback-callbacks';
 107
 108         private static $loggerFields =
 109                 [ 'replLogger', 'connLogger', 'queryLogger', 'perfLogger' ];
 110
 111         public function __construct( array $conf ) {
 112                 $this->localDomain = isset( $conf['localDomain'] )
 113                         ? DatabaseDomain::newFromId( $conf['localDomain'] )
 114                         : DatabaseDomain::newUnspecified();
 115
 116                 $this->maxLag = $conf['maxLag'] ?? null;
 117                 if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
 118                         $this->readOnlyReason = $conf['readOnlyReason'];
 119                 }
 120
 121                 $this->srvCache = $conf['srvCache'] ?? new EmptyBagOStuff();
 122                 $this->memStash = $conf['memStash'] ?? new EmptyBagOStuff();
 123                 $this->wanCache = $conf['wanCache'] ?? WANObjectCache::newEmpty();
 124
 125                 foreach ( self::$loggerFields as $key ) {
 126                         $this->$key = $conf[$key] ?? new \Psr\Log\NullLogger();
 127                 }
 128                 $this->errorLogger = $conf['errorLogger'] ?? function ( Exception $e ) {
 129                         trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
 130                 };
 131                 $this->deprecationLogger = $conf['deprecationLogger'] ?? function ( $msg ) {
 132                         trigger_error( $msg, E_USER_DEPRECATED );
 133                 };
 134
 135                 $this->profiler = $conf['profiler'] ?? null;
 136                 $this->trxProfiler = $conf['trxProfiler'] ?? new TransactionProfiler();
 137
 138                 $this->requestInfo = [
 139                         'IPAddress' => $_SERVER[ 'REMOTE_ADDR' ] ?? '',
 140                         'UserAgent' => $_SERVER['HTTP_USER_AGENT'] ?? '',
 141                         // Headers application can inject via LBFactory::setRequestInfo()
 142                         'ChronologyProtection' => null,
 143                         'ChronologyClientId' => null, // prior $cpClientId value from LBFactory::shutdown()
 144                         'ChronologyPositionIndex' => null // prior $cpIndex value from LBFactory::shutdown()
 145                 ];
 146
 147                 $this->cliMode = $conf['cliMode'] ?? ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' );
 148                 $this->hostname = $conf['hostname'] ?? gethostname();
 149                 $this->agent = $conf['agent'] ?? '';
 150                 $this->defaultGroup = $conf['defaultGroup'] ?? null;
 151
 152                 $this->ticket = mt_rand();
 153         }
 154
 155         public function destroy() {
 156                 $this->shutdown( self::SHUTDOWN_NO_CHRONPROT );
 157                 $this->forEachLBCallMethod( 'disable' );
 158         }
 159
 160         public function getLocalDomainID() {
 161                 return $this->localDomain->getId();
 162         }
 163
 164         public function resolveDomainID( $domain ) {
 165                 return ( $domain !== false ) ? (string)$domain : $this->getLocalDomainID();
 166         }
 167
 168         public function shutdown(
 169                 $mode = self::SHUTDOWN_CHRONPROT_SYNC,
 170                 callable $workCallback = null,
 171                 &$cpIndex = null,
 172                 &$cpClientId = null
 173         ) {
 174                 $chronProt = $this->getChronologyProtector();
 175                 if ( $mode === self::SHUTDOWN_CHRONPROT_SYNC ) {
 176                         $this->shutdownChronologyProtector( $chronProt, $workCallback, 'sync', $cpIndex );
 177                 } elseif ( $mode === self::SHUTDOWN_CHRONPROT_ASYNC ) {
 178                         $this->shutdownChronologyProtector( $chronProt, null, 'async', $cpIndex );
 179                 }
 180
 181                 $cpClientId = $chronProt->getClientId();
 182
 183                 $this->commitMasterChanges( __METHOD__ ); // sanity
 184         }
 185
 186         /**
 187          * @see ILBFactory::newMainLB()
 188          * @param bool $domain
 189          * @return ILoadBalancer
 190          */
 191         abstract public function newMainLB( $domain = false );
 192
 193         /**
 194          * @see ILBFactory::getMainLB()
 195          * @param bool $domain
 196          * @return ILoadBalancer
 197          */
 198         abstract public function getMainLB( $domain = false );
 199
 200         /**
 201          * @see ILBFactory::newExternalLB()
 202          * @param string $cluster
 203          * @return ILoadBalancer
 204          */
 205         abstract public function newExternalLB( $cluster );
 206
 207         /**
 208          * @see ILBFactory::getExternalLB()
 209          * @param string $cluster
 210          * @return ILoadBalancer
 211          */
 212         abstract public function getExternalLB( $cluster );
 213
 214         /**
 215          * Call a method of each tracked load balancer
 216          *
 217          * @param string $methodName
 218          * @param array $args
 219          */
 220         protected function forEachLBCallMethod( $methodName, array $args = [] ) {
 221                 $this->forEachLB(
 222                         function ( ILoadBalancer $loadBalancer, $methodName, array $args ) {
 223                                 $loadBalancer->$methodName( ...$args );
 224                         },
 225                         [ $methodName, $args ]
 226                 );
 227         }
 228
 229         public function flushReplicaSnapshots( $fname = __METHOD__ ) {
 230                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 231         }
 232
 233         final public function commitAll( $fname = __METHOD__, array $options = [] ) {
 234                 $this->commitMasterChanges( $fname, $options );
 235                 $this->forEachLBCallMethod( 'flushMasterSnapshots', [ $fname ] );
 236                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 237         }
 238
 239         final public function beginMasterChanges( $fname = __METHOD__ ) {
 240                 $this->assertTransactionRoundStage( self::ROUND_CURSORY );
 241                 $this->trxRoundStage = self::ROUND_BEGINNING;
 242                 if ( $this->trxRoundId !== false ) {
 243                         throw new DBTransactionError(
 244                                 null,
 245                                 "$fname: transaction round '{$this->trxRoundId}' already started."
 246                         );
 247                 }
 248                 $this->trxRoundId = $fname;
 249                 // Set DBO_TRX flags on all appropriate DBs
 250                 $this->forEachLBCallMethod( 'beginMasterChanges', [ $fname ] );
 251                 $this->trxRoundStage = self::ROUND_CURSORY;
 252         }
 253
 254         final public function commitMasterChanges( $fname = __METHOD__, array $options = [] ) {
 255                 $this->assertTransactionRoundStage( self::ROUND_CURSORY );
 256                 $this->trxRoundStage = self::ROUND_COMMITTING;
 257                 if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
 258                         throw new DBTransactionError(
 259                                 null,
 260                                 "$fname: transaction round '{$this->trxRoundId}' still running."
 261                         );
 262                 }
 263                 /** @noinspection PhpUnusedLocalVariableInspection */
 264                 $scope = ScopedCallback::newScopedIgnoreUserAbort(); // try to ignore client aborts
 265                 // Run pre-commit callbacks and suppress post-commit callbacks, aborting on failure
 266                 do {
 267                         $count = 0; // number of callbacks executed this iteration
 268                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$count ) {
 269                                 $count += $lb->finalizeMasterChanges();
 270                         } );
 271                 } while ( $count > 0 );
 272                 $this->trxRoundId = false;
 273                 // Perform pre-commit checks, aborting on failure
 274                 $this->forEachLBCallMethod( 'approveMasterChanges', [ $options ] );
 275                 // Log the DBs and methods involved in multi-DB transactions
 276                 $this->logIfMultiDbTransaction();
 277                 // Actually perform the commit on all master DB connections and revert DBO_TRX
 278                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 279                 // Run all post-commit callbacks in a separate step
 280                 $this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
 281                 $e = $this->executePostTransactionCallbacks();
 282                 $this->trxRoundStage = self::ROUND_CURSORY;
 283                 // Throw any last post-commit callback error
 284                 if ( $e instanceof Exception ) {
 285                         throw $e;
 286                 }
 287         }
 288
 289         final public function rollbackMasterChanges( $fname = __METHOD__ ) {
 290                 $this->trxRoundStage = self::ROUND_ROLLING_BACK;
 291                 $this->trxRoundId = false;
 292                 // Actually perform the rollback on all master DB connections and revert DBO_TRX
 293                 $this->forEachLBCallMethod( 'rollbackMasterChanges', [ $fname ] );
 294                 // Run all post-commit callbacks in a separate step
 295                 $this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
 296                 $this->executePostTransactionCallbacks();
 297                 $this->trxRoundStage = self::ROUND_CURSORY;
 298         }
 299
 300         /**
 301          * @return Exception|null
 302          */
 303         private function executePostTransactionCallbacks() {
 304                 // Run all post-commit callbacks until new ones stop getting added
 305                 $e = null; // first callback exception
 306                 do {
 307                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 308                                 $ex = $lb->runMasterTransactionIdleCallbacks();
 309                                 $e = $e ?: $ex;
 310                         } );
 311                 } while ( $this->hasMasterChanges() );
 312                 // Run all listener callbacks once
 313                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 314                         $ex = $lb->runMasterTransactionListenerCallbacks();
 315                         $e = $e ?: $ex;
 316                 } );
 317
 318                 return $e;
 319         }
 320
 321         public function hasTransactionRound() {
 322                 return ( $this->trxRoundId !== false );
 323         }
 324
 325         public function isReadyForRoundOperations() {
 326                 return ( $this->trxRoundStage === self::ROUND_CURSORY );
 327         }
 328
 329         /**
 330          * Log query info if multi DB transactions are going to be committed now
 331          */
 332         private function logIfMultiDbTransaction() {
 333                 $callersByDB = [];
 334                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$callersByDB ) {
 335                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 336                         $callers = $lb->pendingMasterChangeCallers();
 337                         if ( $callers ) {
 338                                 $callersByDB[$masterName] = $callers;
 339                         }
 340                 } );
 341
 342                 if ( count( $callersByDB ) >= 2 ) {
 343                         $dbs = implode( ', ', array_keys( $callersByDB ) );
 344                         $msg = "Multi-DB transaction [{$dbs}]:\n";
 345                         foreach ( $callersByDB as $db => $callers ) {
 346                                 $msg .= "$db: " . implode( '; ', $callers ) . "\n";
 347                         }
 348                         $this->queryLogger->info( $msg );
 349                 }
 350         }
 351
 352         public function hasMasterChanges() {
 353                 $ret = false;
 354                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 355                         $ret = $ret || $lb->hasMasterChanges();
 356                 } );
 357
 358                 return $ret;
 359         }
 360
 361         public function laggedReplicaUsed() {
 362                 $ret = false;
 363                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 364                         $ret = $ret || $lb->laggedReplicaUsed();
 365                 } );
 366
 367                 return $ret;
 368         }
 369
 370         public function hasOrMadeRecentMasterChanges( $age = null ) {
 371                 $ret = false;
 372                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $age, &$ret ) {
 373                         $ret = $ret || $lb->hasOrMadeRecentMasterChanges( $age );
 374                 } );
 375                 return $ret;
 376         }
 377
 378         public function waitForReplication( array $opts = [] ) {
 379                 $opts += [
 380                         'domain' => false,
 381                         'cluster' => false,
 382                         'timeout' => $this->cliMode ? 60 : 1,
 383                         'ifWritesSince' => null
 384                 ];
 385
 386                 if ( $opts['domain'] === false && isset( $opts['wiki'] ) ) {
 387                         $opts['domain'] = $opts['wiki']; // b/c
 388                 }
 389
 390                 // Figure out which clusters need to be checked
 391                 /** @var ILoadBalancer[] $lbs */
 392                 $lbs = [];
 393                 if ( $opts['cluster'] !== false ) {
 394                         $lbs[] = $this->getExternalLB( $opts['cluster'] );
 395                 } elseif ( $opts['domain'] !== false ) {
 396                         $lbs[] = $this->getMainLB( $opts['domain'] );
 397                 } else {
 398                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$lbs ) {
 399                                 $lbs[] = $lb;
 400                         } );
 401                         if ( !$lbs ) {
 402                                 return; // nothing actually used
 403                         }
 404                 }
 405
 406                 // Get all the master positions of applicable DBs right now.
 407                 // This can be faster since waiting on one cluster reduces the
 408                 // time needed to wait on the next clusters.
 409                 $masterPositions = array_fill( 0, count( $lbs ), false );
 410                 foreach ( $lbs as $i => $lb ) {
 411                         if ( $lb->getServerCount() <= 1 ) {
 412                                 // T29975 - Don't try to wait for replica DBs if there are none
 413                                 // Prevents permission error when getting master position
 414                                 continue;
 415                         } elseif ( $opts['ifWritesSince']
 416                                 && $lb->lastMasterChangeTimestamp() < $opts['ifWritesSince']
 417                         ) {
 418                                 continue; // no writes since the last wait
 419                         }
 420                         $masterPositions[$i] = $lb->getMasterPos();
 421                 }
 422
 423                 // Run any listener callbacks *after* getting the DB positions. The more
 424                 // time spent in the callbacks, the less time is spent in waitForAll().
 425                 foreach ( $this->replicationWaitCallbacks as $callback ) {
 426                         $callback();
 427                 }
 428
 429                 $failed = [];
 430                 foreach ( $lbs as $i => $lb ) {
 431                         if ( $masterPositions[$i] ) {
 432                                 // The RDBMS may not support getMasterPos()
 433                                 if ( !$lb->waitForAll( $masterPositions[$i], $opts['timeout'] ) ) {
 434                                         $failed[] = $lb->getServerName( $lb->getWriterIndex() );
 435                                 }
 436                         }
 437                 }
 438
 439                 return !$failed;
 440         }
 441
 442         public function setWaitForReplicationListener( $name, callable $callback = null ) {
 443                 if ( $callback ) {
 444                         $this->replicationWaitCallbacks[$name] = $callback;
 445                 } else {
 446                         unset( $this->replicationWaitCallbacks[$name] );
 447                 }
 448         }
 449
 450         public function getEmptyTransactionTicket( $fname ) {
 451                 if ( $this->hasMasterChanges() ) {
 452                         $this->queryLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 453                                 ( new RuntimeException() )->getTraceAsString() );
 454
 455                         return null;
 456                 }
 457
 458                 return $this->ticket;
 459         }
 460
 461         final public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
 462                 if ( $ticket !== $this->ticket ) {
 463                         $this->perfLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 464                                 ( new RuntimeException() )->getTraceAsString() );
 465
 466                         return;
 467                 }
 468
 469                 // The transaction owner and any caller with the empty transaction ticket can commit
 470                 // so that getEmptyTransactionTicket() callers don't risk seeing DBTransactionError.
 471                 if ( $this->trxRoundId !== false && $fname !== $this->trxRoundId ) {
 472                         $this->queryLogger->info( "$fname: committing on behalf of {$this->trxRoundId}." );
 473                         $fnameEffective = $this->trxRoundId;
 474                 } else {
 475                         $fnameEffective = $fname;
 476                 }
 477
 478                 $this->commitMasterChanges( $fnameEffective );
 479                 $waitSucceeded = $this->waitForReplication( $opts );
 480                 // If a nested caller committed on behalf of $fname, start another empty $fname
 481                 // transaction, leaving the caller with the same empty transaction state as before.
 482                 if ( $fnameEffective !== $fname ) {
 483                         $this->beginMasterChanges( $fnameEffective );
 484                 }
 485                 return $waitSucceeded;
 486         }
 487
 488         public function getChronologyProtectorTouched( $dbName ) {
 489                 return $this->getChronologyProtector()->getTouched( $dbName );
 490         }
 491
 492         public function disableChronologyProtection() {
 493                 $this->getChronologyProtector()->setEnabled( false );
 494         }
 495
 496         /**
 497          * @return ChronologyProtector
 498          */
 499         protected function getChronologyProtector() {
 500                 if ( $this->chronProt ) {
 501                         return $this->chronProt;
 502                 }
 503
 504                 $this->chronProt = new ChronologyProtector(
 505                         $this->memStash,
 506                         [
 507                                 'ip' => $this->requestInfo['IPAddress'],
 508                                 'agent' => $this->requestInfo['UserAgent'],
 509                                 'clientId' => $this->requestInfo['ChronologyClientId']
 510                         ],
 511                         $this->requestInfo['ChronologyPositionIndex']
 512                 );
 513                 $this->chronProt->setLogger( $this->replLogger );
 514
 515                 if ( $this->cliMode ) {
 516                         $this->chronProt->setEnabled( false );
 517                 } elseif ( $this->requestInfo['ChronologyProtection'] === 'false' ) {
 518                         // Request opted out of using position wait logic. This is useful for requests
 519                         // done by the job queue or background ETL that do not have a meaningful session.
 520                         $this->chronProt->setWaitEnabled( false );
 521                 } elseif ( $this->memStash instanceof EmptyBagOStuff ) {
 522                         // No where to store any DB positions and wait for them to appear
 523                         $this->chronProt->setEnabled( false );
 524                         $this->replLogger->info( 'Cannot use ChronologyProtector with EmptyBagOStuff.' );
 525                 }
 526
 527                 $this->replLogger->debug( __METHOD__ . ': using request info ' .
 528                         json_encode( $this->requestInfo, JSON_PRETTY_PRINT ) );
 529
 530                 return $this->chronProt;
 531         }
 532
 533         /**
 534          * Get and record all of the staged DB positions into persistent memory storage
 535          *
 536          * @param ChronologyProtector $cp
 537          * @param callable|null $workCallback Work to do instead of waiting on syncing positions
 538          * @param string $mode One of (sync, async); whether to wait on remote datacenters
 539          * @param int|null &$cpIndex DB position key write counter; incremented on update
 540          */
 541         protected function shutdownChronologyProtector(
 542                 ChronologyProtector $cp, $workCallback, $mode, &$cpIndex = null
 543         ) {
 544                 // Record all the master positions needed
 545                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $cp ) {
 546                         $cp->shutdownLB( $lb );
 547                 } );
 548                 // Write them to the persistent stash. Try to do something useful by running $work
 549                 // while ChronologyProtector waits for the stash write to replicate to all DCs.
 550                 $unsavedPositions = $cp->shutdown( $workCallback, $mode, $cpIndex );
 551                 if ( $unsavedPositions && $workCallback ) {
 552                         // Invoke callback in case it did not cache the result yet
 553                         $workCallback(); // work now to block for less time in waitForAll()
 554                 }
 555                 // If the positions failed to write to the stash, at least wait on local datacenter
 556                 // replica DBs to catch up before responding. Even if there are several DCs, this increases
 557                 // the chance that the user will see their own changes immediately afterwards. As long
 558                 // as the sticky DC cookie applies (same domain), this is not even an issue.
 559                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $unsavedPositions ) {
 560                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 561                         if ( isset( $unsavedPositions[$masterName] ) ) {
 562                                 $lb->waitForAll( $unsavedPositions[$masterName] );
 563                         }
 564                 } );
 565         }
 566
 567         /**
 568          * Base parameters to ILoadBalancer::__construct()
 569          * @return array
 570          */
 571         final protected function baseLoadBalancerParams() {
 572                 if ( $this->trxRoundStage === self::ROUND_COMMIT_CALLBACKS ) {
 573                         $initStage = ILoadBalancer::STAGE_POSTCOMMIT_CALLBACKS;
 574                 } elseif ( $this->trxRoundStage === self::ROUND_ROLLBACK_CALLBACKS ) {
 575                         $initStage = ILoadBalancer::STAGE_POSTROLLBACK_CALLBACKS;
 576                 } else {
 577                         $initStage = null;
 578                 }
 579
 580                 return [
 581                         'localDomain' => $this->localDomain,
 582                         'readOnlyReason' => $this->readOnlyReason,
 583                         'srvCache' => $this->srvCache,
 584                         'wanCache' => $this->wanCache,
 585                         'profiler' => $this->profiler,
 586                         'trxProfiler' => $this->trxProfiler,
 587                         'queryLogger' => $this->queryLogger,
 588                         'connLogger' => $this->connLogger,
 589                         'replLogger' => $this->replLogger,
 590                         'errorLogger' => $this->errorLogger,
 591                         'deprecationLogger' => $this->deprecationLogger,
 592                         'hostname' => $this->hostname,
 593                         'cliMode' => $this->cliMode,
 594                         'agent' => $this->agent,
 595                         'maxLag' => $this->maxLag,
 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         /**
 627          * @param string $prefix
 628          * @deprecated Since 1.33
 629          */
 630         public function setDomainPrefix( $prefix ) {
 631                 $this->setLocalDomainPrefix( $prefix );
 632         }
 633
 634         public function setLocalDomainPrefix( $prefix ) {
 635                 $this->localDomain = new DatabaseDomain(
 636                         $this->localDomain->getDatabase(),
 637                         $this->localDomain->getSchema(),
 638                         $prefix
 639                 );
 640
 641                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $prefix ) {
 642                         $lb->setLocalDomainPrefix( $prefix );
 643                 } );
 644         }
 645
 646         public function redefineLocalDomain( $domain ) {
 647                 $this->closeAll();
 648
 649                 $this->localDomain = DatabaseDomain::newFromId( $domain );
 650
 651                 $this->forEachLB( function ( ILoadBalancer $lb ) {
 652                         $lb->redefineLocalDomain( $this->localDomain );
 653                 } );
 654         }
 655
 656         public function closeAll() {
 657                 $this->forEachLBCallMethod( 'closeAll' );
 658         }
 659
 660         public function setAgentName( $agent ) {
 661                 $this->agent = $agent;
 662         }
 663
 664         public function appendShutdownCPIndexAsQuery( $url, $index ) {
 665                 $usedCluster = 0;
 666                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$usedCluster ) {
 667                         $usedCluster |= ( $lb->getServerCount() > 1 );
 668                 } );
 669
 670                 if ( !$usedCluster ) {
 671                         return $url; // no master/replica clusters touched
 672                 }
 673
 674                 return strpos( $url, '?' ) === false ? "$url?cpPosIndex=$index" : "$url&cpPosIndex=$index";
 675         }
 676
 677         /**
 678          * @param int $index Write index
 679          * @param int $time UNIX timestamp; can be used to detect stale cookies (T190082)
 680          * @param string $clientId Agent ID hash from ILBFactory::shutdown()
 681          * @return string Timestamp-qualified write index of the form "<index>@<timestamp>#<hash>"
 682          * @since 1.32
 683          */
 684         public static function makeCookieValueFromCPIndex( $index, $time, $clientId ) {
 685                 return "$index@$time#$clientId";
 686         }
 687
 688         /**
 689          * @param string $value Possible result of LBFactory::makeCookieValueFromCPIndex()
 690          * @param int $minTimestamp Lowest UNIX timestamp that a non-expired value can have
 691          * @return array (index: int or null, clientId: string or null)
 692          * @since 1.32
 693          */
 694         public static function getCPInfoFromCookieValue( $value, $minTimestamp ) {
 695                 static $placeholder = [ 'index' => null, 'clientId' => null ];
 696
 697                 if ( !preg_match( '/^(\d+)@(\d+)#([0-9a-f]{32})$/', $value, $m ) ) {
 698                         return $placeholder; // invalid
 699                 }
 700
 701                 $index = (int)$m[1];
 702                 if ( $index <= 0 ) {
 703                         return $placeholder; // invalid
 704                 } elseif ( isset( $m[2] ) && $m[2] !== '' && (int)$m[2] < $minTimestamp ) {
 705                         return $placeholder; // expired
 706                 }
 707
 708                 $clientId = ( isset( $m[3] ) && $m[3] !== '' ) ? $m[3] : null;
 709
 710                 return [ 'index' => $index, 'clientId' => $clientId ];
 711         }
 712
 713         public function setRequestInfo( array $info ) {
 714                 if ( $this->chronProt ) {
 715                         throw new LogicException( 'ChronologyProtector already initialized.' );
 716                 }
 717
 718                 $this->requestInfo = $info + $this->requestInfo;
 719         }
 720
 721         /**
 722          * @param string $stage
 723          */
 724         private function assertTransactionRoundStage( $stage ) {
 725                 if ( $this->trxRoundStage !== $stage ) {
 726                         throw new DBTransactionError(
 727                                 null,
 728                                 "Transaction round stage must be '$stage' (not '{$this->trxRoundStage}')"
 729                         );
 730                 }
 731         }
 732
 733         function __destruct() {
 734                 $this->destroy();
 735         }
 736 }