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
  34 /**
  35  * An interface for generating database load balancers
  36  * @ingroup Database
  37  */
  38 abstract class LBFactory implements ILBFactory {
  39         /** @var ChronologyProtector */
  40         protected $chronProt;
  41         /** @var object|string Class name or object With profileIn/profileOut methods */
  42         protected $profiler;
  43         /** @var TransactionProfiler */
  44         protected $trxProfiler;
  45         /** @var LoggerInterface */
  46         protected $replLogger;
  47         /** @var LoggerInterface */
  48         protected $connLogger;
  49         /** @var LoggerInterface */
  50         protected $queryLogger;
  51         /** @var LoggerInterface */
  52         protected $perfLogger;
  53         /** @var callable Error logger */
  54         protected $errorLogger;
  55         /** @var callable Deprecation logger */
  56         protected $deprecationLogger;
  57         /** @var BagOStuff */
  58         protected $srvCache;
  59         /** @var BagOStuff */
  60         protected $memStash;
  61         /** @var WANObjectCache */
  62         protected $wanCache;
  63
  64         /** @var DatabaseDomain Local domain */
  65         protected $localDomain;
  66         /** @var string Local hostname of the app server */
  67         protected $hostname;
  68         /** @var array Web request information about the client */
  69         protected $requestInfo;
  70
  71         /** @var mixed */
  72         protected $ticket;
  73         /** @var string|bool String if a requested DBO_TRX transaction round is active */
  74         protected $trxRoundId = false;
  75         /** @var string|bool Reason all LBs are read-only or false if not */
  76         protected $readOnlyReason = false;
  77         /** @var callable[] */
  78         protected $replicationWaitCallbacks = [];
  79
  80         /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
  81         protected $tableAliases = [];
  82         /** @var string[] Map of (index alias => index) */
  83         protected $indexAliases = [];
  84
  85         /** @var bool Whether this PHP instance is for a CLI script */
  86         protected $cliMode;
  87         /** @var string Agent name for query profiling */
  88         protected $agent;
  89
  90         private static $loggerFields =
  91                 [ 'replLogger', 'connLogger', 'queryLogger', 'perfLogger' ];
  92
  93         public function __construct( array $conf ) {
  94                 $this->localDomain = isset( $conf['localDomain'] )
  95                         ? DatabaseDomain::newFromId( $conf['localDomain'] )
  96                         : DatabaseDomain::newUnspecified();
  97
  98                 if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
  99                         $this->readOnlyReason = $conf['readOnlyReason'];
 100                 }
 101
 102                 $this->srvCache = isset( $conf['srvCache'] ) ? $conf['srvCache'] : new EmptyBagOStuff();
 103                 $this->memStash = isset( $conf['memStash'] ) ? $conf['memStash'] : new EmptyBagOStuff();
 104                 $this->wanCache = isset( $conf['wanCache'] )
 105                         ? $conf['wanCache']
 106                         : WANObjectCache::newEmpty();
 107
 108                 foreach ( self::$loggerFields as $key ) {
 109                         $this->$key = isset( $conf[$key] ) ? $conf[$key] : new \Psr\Log\NullLogger();
 110                 }
 111                 $this->errorLogger = isset( $conf['errorLogger'] )
 112                         ? $conf['errorLogger']
 113                         : function ( Exception $e ) {
 114                                 trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
 115                         };
 116                 $this->deprecationLogger = isset( $conf['deprecationLogger'] )
 117                         ? $conf['deprecationLogger']
 118                         : function ( $msg ) {
 119                                 trigger_error( $msg, E_USER_DEPRECATED );
 120                         };
 121
 122                 $this->profiler = isset( $conf['profiler'] ) ? $conf['profiler'] : null;
 123                 $this->trxProfiler = isset( $conf['trxProfiler'] )
 124                         ? $conf['trxProfiler']
 125                         : new TransactionProfiler();
 126
 127                 $this->requestInfo = [
 128                         'IPAddress' => isset( $_SERVER[ 'REMOTE_ADDR' ] ) ? $_SERVER[ 'REMOTE_ADDR' ] : '',
 129                         'UserAgent' => isset( $_SERVER['HTTP_USER_AGENT'] ) ? $_SERVER['HTTP_USER_AGENT'] : '',
 130                         'ChronologyProtection' => 'true',
 131                         'ChronologyPositionIndex' => isset( $_GET['cpPosIndex'] ) ? $_GET['cpPosIndex'] : null
 132                 ];
 133
 134                 $this->cliMode = isset( $conf['cliMode'] )
 135                         ? $conf['cliMode']
 136                         : ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' );
 137                 $this->hostname = isset( $conf['hostname'] ) ? $conf['hostname'] : gethostname();
 138                 $this->agent = isset( $conf['agent'] ) ? $conf['agent'] : '';
 139
 140                 $this->ticket = mt_rand();
 141         }
 142
 143         public function destroy() {
 144                 $this->shutdown( self::SHUTDOWN_NO_CHRONPROT );
 145                 $this->forEachLBCallMethod( 'disable' );
 146         }
 147
 148         public function shutdown(
 149                 $mode = self::SHUTDOWN_CHRONPROT_SYNC, callable $workCallback = null, &$cpIndex = null
 150         ) {
 151                 $chronProt = $this->getChronologyProtector();
 152                 if ( $mode === self::SHUTDOWN_CHRONPROT_SYNC ) {
 153                         $this->shutdownChronologyProtector( $chronProt, $workCallback, 'sync', $cpIndex );
 154                 } elseif ( $mode === self::SHUTDOWN_CHRONPROT_ASYNC ) {
 155                         $this->shutdownChronologyProtector( $chronProt, null, 'async', $cpIndex );
 156                 }
 157
 158                 $this->commitMasterChanges( __METHOD__ ); // sanity
 159         }
 160
 161         /**
 162          * @see ILBFactory::newMainLB()
 163          * @param bool $domain
 164          * @return LoadBalancer
 165          */
 166         abstract public function newMainLB( $domain = false );
 167
 168         /**
 169          * @see ILBFactory::getMainLB()
 170          * @param bool $domain
 171          * @return LoadBalancer
 172          */
 173         abstract public function getMainLB( $domain = false );
 174
 175         /**
 176          * @see ILBFactory::newExternalLB()
 177          * @param string $cluster
 178          * @return LoadBalancer
 179          */
 180         abstract public function newExternalLB( $cluster );
 181
 182         /**
 183          * @see ILBFactory::getExternalLB()
 184          * @param string $cluster
 185          * @return LoadBalancer
 186          */
 187         abstract public function getExternalLB( $cluster );
 188
 189         /**
 190          * Call a method of each tracked load balancer
 191          *
 192          * @param string $methodName
 193          * @param array $args
 194          */
 195         protected function forEachLBCallMethod( $methodName, array $args = [] ) {
 196                 $this->forEachLB(
 197                         function ( ILoadBalancer $loadBalancer, $methodName, array $args ) {
 198                                 call_user_func_array( [ $loadBalancer, $methodName ], $args );
 199                         },
 200                         [ $methodName, $args ]
 201                 );
 202         }
 203
 204         public function flushReplicaSnapshots( $fname = __METHOD__ ) {
 205                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 206         }
 207
 208         public function commitAll( $fname = __METHOD__, array $options = [] ) {
 209                 $this->commitMasterChanges( $fname, $options );
 210                 $this->forEachLBCallMethod( 'commitAll', [ $fname ] );
 211         }
 212
 213         public function beginMasterChanges( $fname = __METHOD__ ) {
 214                 if ( $this->trxRoundId !== false ) {
 215                         throw new DBTransactionError(
 216                                 null,
 217                                 "$fname: transaction round '{$this->trxRoundId}' already started."
 218                         );
 219                 }
 220                 $this->trxRoundId = $fname;
 221                 // Set DBO_TRX flags on all appropriate DBs
 222                 $this->forEachLBCallMethod( 'beginMasterChanges', [ $fname ] );
 223         }
 224
 225         public function commitMasterChanges( $fname = __METHOD__, array $options = [] ) {
 226                 if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
 227                         throw new DBTransactionError(
 228                                 null,
 229                                 "$fname: transaction round '{$this->trxRoundId}' still running."
 230                         );
 231                 }
 232                 /** @noinspection PhpUnusedLocalVariableInspection */
 233                 $scope = $this->getScopedPHPBehaviorForCommit(); // try to ignore client aborts
 234                 // Run pre-commit callbacks and suppress post-commit callbacks, aborting on failure
 235                 $this->forEachLBCallMethod( 'finalizeMasterChanges' );
 236                 $this->trxRoundId = false;
 237                 // Perform pre-commit checks, aborting on failure
 238                 $this->forEachLBCallMethod( 'approveMasterChanges', [ $options ] );
 239                 // Log the DBs and methods involved in multi-DB transactions
 240                 $this->logIfMultiDbTransaction();
 241                 // Actually perform the commit on all master DB connections and revert DBO_TRX
 242                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 243                 // Run all post-commit callbacks
 244                 /** @var Exception $e */
 245                 $e = null; // first callback exception
 246                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 247                         $ex = $lb->runMasterPostTrxCallbacks( IDatabase::TRIGGER_COMMIT );
 248                         $e = $e ?: $ex;
 249                 } );
 250                 // Commit any dangling DBO_TRX transactions from callbacks on one DB to another DB
 251                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 252                 // Throw any last post-commit callback error
 253                 if ( $e instanceof Exception ) {
 254                         throw $e;
 255                 }
 256         }
 257
 258         public function rollbackMasterChanges( $fname = __METHOD__ ) {
 259                 $this->trxRoundId = false;
 260                 $this->forEachLBCallMethod( 'suppressTransactionEndCallbacks' );
 261                 $this->forEachLBCallMethod( 'rollbackMasterChanges', [ $fname ] );
 262                 // Run all post-rollback callbacks
 263                 $this->forEachLB( function ( ILoadBalancer $lb ) {
 264                         $lb->runMasterPostTrxCallbacks( IDatabase::TRIGGER_ROLLBACK );
 265                 } );
 266         }
 267
 268         public function hasTransactionRound() {
 269                 return ( $this->trxRoundId !== false );
 270         }
 271
 272         /**
 273          * Log query info if multi DB transactions are going to be committed now
 274          */
 275         private function logIfMultiDbTransaction() {
 276                 $callersByDB = [];
 277                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$callersByDB ) {
 278                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 279                         $callers = $lb->pendingMasterChangeCallers();
 280                         if ( $callers ) {
 281                                 $callersByDB[$masterName] = $callers;
 282                         }
 283                 } );
 284
 285                 if ( count( $callersByDB ) >= 2 ) {
 286                         $dbs = implode( ', ', array_keys( $callersByDB ) );
 287                         $msg = "Multi-DB transaction [{$dbs}]:\n";
 288                         foreach ( $callersByDB as $db => $callers ) {
 289                                 $msg .= "$db: " . implode( '; ', $callers ) . "\n";
 290                         }
 291                         $this->queryLogger->info( $msg );
 292                 }
 293         }
 294
 295         public function hasMasterChanges() {
 296                 $ret = false;
 297                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 298                         $ret = $ret || $lb->hasMasterChanges();
 299                 } );
 300
 301                 return $ret;
 302         }
 303
 304         public function laggedReplicaUsed() {
 305                 $ret = false;
 306                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 307                         $ret = $ret || $lb->laggedReplicaUsed();
 308                 } );
 309
 310                 return $ret;
 311         }
 312
 313         public function hasOrMadeRecentMasterChanges( $age = null ) {
 314                 $ret = false;
 315                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $age, &$ret ) {
 316                         $ret = $ret || $lb->hasOrMadeRecentMasterChanges( $age );
 317                 } );
 318                 return $ret;
 319         }
 320
 321         public function waitForReplication( array $opts = [] ) {
 322                 $opts += [
 323                         'domain' => false,
 324                         'cluster' => false,
 325                         'timeout' => $this->cliMode ? 60 : 10,
 326                         'ifWritesSince' => null
 327                 ];
 328
 329                 if ( $opts['domain'] === false && isset( $opts['wiki'] ) ) {
 330                         $opts['domain'] = $opts['wiki']; // b/c
 331                 }
 332
 333                 // Figure out which clusters need to be checked
 334                 /** @var ILoadBalancer[] $lbs */
 335                 $lbs = [];
 336                 if ( $opts['cluster'] !== false ) {
 337                         $lbs[] = $this->getExternalLB( $opts['cluster'] );
 338                 } elseif ( $opts['domain'] !== false ) {
 339                         $lbs[] = $this->getMainLB( $opts['domain'] );
 340                 } else {
 341                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$lbs ) {
 342                                 $lbs[] = $lb;
 343                         } );
 344                         if ( !$lbs ) {
 345                                 return; // nothing actually used
 346                         }
 347                 }
 348
 349                 // Get all the master positions of applicable DBs right now.
 350                 // This can be faster since waiting on one cluster reduces the
 351                 // time needed to wait on the next clusters.
 352                 $masterPositions = array_fill( 0, count( $lbs ), false );
 353                 foreach ( $lbs as $i => $lb ) {
 354                         if ( $lb->getServerCount() <= 1 ) {
 355                                 // T29975 - Don't try to wait for replica DBs if there are none
 356                                 // Prevents permission error when getting master position
 357                                 continue;
 358                         } elseif ( $opts['ifWritesSince']
 359                                 && $lb->lastMasterChangeTimestamp() < $opts['ifWritesSince']
 360                         ) {
 361                                 continue; // no writes since the last wait
 362                         }
 363                         $masterPositions[$i] = $lb->getMasterPos();
 364                 }
 365
 366                 // Run any listener callbacks *after* getting the DB positions. The more
 367                 // time spent in the callbacks, the less time is spent in waitForAll().
 368                 foreach ( $this->replicationWaitCallbacks as $callback ) {
 369                         $callback();
 370                 }
 371
 372                 $failed = [];
 373                 foreach ( $lbs as $i => $lb ) {
 374                         if ( $masterPositions[$i] ) {
 375                                 // The RDBMS may not support getMasterPos()
 376                                 if ( !$lb->waitForAll( $masterPositions[$i], $opts['timeout'] ) ) {
 377                                         $failed[] = $lb->getServerName( $lb->getWriterIndex() );
 378                                 }
 379                         }
 380                 }
 381
 382                 if ( $failed ) {
 383                         throw new DBReplicationWaitError(
 384                                 null,
 385                                 "Could not wait for replica DBs to catch up to " .
 386                                 implode( ', ', $failed )
 387                         );
 388                 }
 389         }
 390
 391         public function setWaitForReplicationListener( $name, callable $callback = null ) {
 392                 if ( $callback ) {
 393                         $this->replicationWaitCallbacks[$name] = $callback;
 394                 } else {
 395                         unset( $this->replicationWaitCallbacks[$name] );
 396                 }
 397         }
 398
 399         public function getEmptyTransactionTicket( $fname ) {
 400                 if ( $this->hasMasterChanges() ) {
 401                         $this->queryLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 402                                 ( new RuntimeException() )->getTraceAsString() );
 403
 404                         return null;
 405                 }
 406
 407                 return $this->ticket;
 408         }
 409
 410         public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
 411                 if ( $ticket !== $this->ticket ) {
 412                         $this->perfLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 413                                 ( new RuntimeException() )->getTraceAsString() );
 414
 415                         return;
 416                 }
 417
 418                 // The transaction owner and any caller with the empty transaction ticket can commit
 419                 // so that getEmptyTransactionTicket() callers don't risk seeing DBTransactionError.
 420                 if ( $this->trxRoundId !== false && $fname !== $this->trxRoundId ) {
 421                         $this->queryLogger->info( "$fname: committing on behalf of {$this->trxRoundId}." );
 422                         $fnameEffective = $this->trxRoundId;
 423                 } else {
 424                         $fnameEffective = $fname;
 425                 }
 426
 427                 $this->commitMasterChanges( $fnameEffective );
 428                 $this->waitForReplication( $opts );
 429                 // If a nested caller committed on behalf of $fname, start another empty $fname
 430                 // transaction, leaving the caller with the same empty transaction state as before.
 431                 if ( $fnameEffective !== $fname ) {
 432                         $this->beginMasterChanges( $fnameEffective );
 433                 }
 434         }
 435
 436         public function getChronologyProtectorTouched( $dbName ) {
 437                 return $this->getChronologyProtector()->getTouched( $dbName );
 438         }
 439
 440         public function disableChronologyProtection() {
 441                 $this->getChronologyProtector()->setEnabled( false );
 442         }
 443
 444         /**
 445          * @return ChronologyProtector
 446          */
 447         protected function getChronologyProtector() {
 448                 if ( $this->chronProt ) {
 449                         return $this->chronProt;
 450                 }
 451
 452                 $this->chronProt = new ChronologyProtector(
 453                         $this->memStash,
 454                         [
 455                                 'ip' => $this->requestInfo['IPAddress'],
 456                                 'agent' => $this->requestInfo['UserAgent'],
 457                         ],
 458                         $this->requestInfo['ChronologyPositionIndex']
 459                 );
 460                 $this->chronProt->setLogger( $this->replLogger );
 461
 462                 if ( $this->cliMode ) {
 463                         $this->chronProt->setEnabled( false );
 464                 } elseif ( $this->requestInfo['ChronologyProtection'] === 'false' ) {
 465                         // Request opted out of using position wait logic. This is useful for requests
 466                         // done by the job queue or background ETL that do not have a meaningful session.
 467                         $this->chronProt->setWaitEnabled( false );
 468                 }
 469
 470                 $this->replLogger->debug( __METHOD__ . ': using request info ' .
 471                         json_encode( $this->requestInfo, JSON_PRETTY_PRINT ) );
 472
 473                 return $this->chronProt;
 474         }
 475
 476         /**
 477          * Get and record all of the staged DB positions into persistent memory storage
 478          *
 479          * @param ChronologyProtector $cp
 480          * @param callable|null $workCallback Work to do instead of waiting on syncing positions
 481          * @param string $mode One of (sync, async); whether to wait on remote datacenters
 482          * @param int|null &$cpIndex DB position key write counter; incremented on update
 483          */
 484         protected function shutdownChronologyProtector(
 485                 ChronologyProtector $cp, $workCallback, $mode, &$cpIndex = null
 486         ) {
 487                 // Record all the master positions needed
 488                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $cp ) {
 489                         $cp->shutdownLB( $lb );
 490                 } );
 491                 // Write them to the persistent stash. Try to do something useful by running $work
 492                 // while ChronologyProtector waits for the stash write to replicate to all DCs.
 493                 $unsavedPositions = $cp->shutdown( $workCallback, $mode, $cpIndex );
 494                 if ( $unsavedPositions && $workCallback ) {
 495                         // Invoke callback in case it did not cache the result yet
 496                         $workCallback(); // work now to block for less time in waitForAll()
 497                 }
 498                 // If the positions failed to write to the stash, at least wait on local datacenter
 499                 // replica DBs to catch up before responding. Even if there are several DCs, this increases
 500                 // the chance that the user will see their own changes immediately afterwards. As long
 501                 // as the sticky DC cookie applies (same domain), this is not even an issue.
 502                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $unsavedPositions ) {
 503                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 504                         if ( isset( $unsavedPositions[$masterName] ) ) {
 505                                 $lb->waitForAll( $unsavedPositions[$masterName] );
 506                         }
 507                 } );
 508         }
 509
 510         /**
 511          * Base parameters to LoadBalancer::__construct()
 512          * @return array
 513          */
 514         final protected function baseLoadBalancerParams() {
 515                 return [
 516                         'localDomain' => $this->localDomain,
 517                         'readOnlyReason' => $this->readOnlyReason,
 518                         'srvCache' => $this->srvCache,
 519                         'wanCache' => $this->wanCache,
 520                         'profiler' => $this->profiler,
 521                         'trxProfiler' => $this->trxProfiler,
 522                         'queryLogger' => $this->queryLogger,
 523                         'connLogger' => $this->connLogger,
 524                         'replLogger' => $this->replLogger,
 525                         'errorLogger' => $this->errorLogger,
 526                         'deprecationLogger' => $this->deprecationLogger,
 527                         'hostname' => $this->hostname,
 528                         'cliMode' => $this->cliMode,
 529                         'agent' => $this->agent,
 530                         'chronologyProtector' => $this->getChronologyProtector()
 531                 ];
 532         }
 533
 534         /**
 535          * @param ILoadBalancer $lb
 536          */
 537         protected function initLoadBalancer( ILoadBalancer $lb ) {
 538                 if ( $this->trxRoundId !== false ) {
 539                         $lb->beginMasterChanges( $this->trxRoundId ); // set DBO_TRX
 540                 }
 541
 542                 $lb->setTableAliases( $this->tableAliases );
 543                 $lb->setIndexAliases( $this->indexAliases );
 544         }
 545
 546         public function setTableAliases( array $aliases ) {
 547                 $this->tableAliases = $aliases;
 548         }
 549
 550         public function setIndexAliases( array $aliases ) {
 551                 $this->indexAliases = $aliases;
 552         }
 553
 554         public function setDomainPrefix( $prefix ) {
 555                 $this->localDomain = new DatabaseDomain(
 556                         $this->localDomain->getDatabase(),
 557                         null,
 558                         $prefix
 559                 );
 560
 561                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $prefix ) {
 562                         $lb->setDomainPrefix( $prefix );
 563                 } );
 564         }
 565
 566         public function closeAll() {
 567                 $this->forEachLBCallMethod( 'closeAll', [] );
 568         }
 569
 570         public function setAgentName( $agent ) {
 571                 $this->agent = $agent;
 572         }
 573
 574         public function appendShutdownCPIndexAsQuery( $url, $index ) {
 575                 $usedCluster = 0;
 576                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$usedCluster ) {
 577                         $usedCluster |= ( $lb->getServerCount() > 1 );
 578                 } );
 579
 580                 if ( !$usedCluster ) {
 581                         return $url; // no master/replica clusters touched
 582                 }
 583
 584                 return strpos( $url, '?' ) === false ? "$url?cpPosIndex=$index" : "$url&cpPosIndex=$index";
 585         }
 586
 587         public function setRequestInfo( array $info ) {
 588                 $this->requestInfo = $info + $this->requestInfo;
 589         }
 590
 591         /**
 592          * Make PHP ignore user aborts/disconnects until the returned
 593          * value leaves scope. This returns null and does nothing in CLI mode.
 594          *
 595          * @return ScopedCallback|null
 596          */
 597         final protected function getScopedPHPBehaviorForCommit() {
 598                 if ( PHP_SAPI != 'cli' ) { // https://bugs.php.net/bug.php?id=47540
 599                         $old = ignore_user_abort( true ); // avoid half-finished operations
 600                         return new ScopedCallback( function () use ( $old ) {
 601                                 ignore_user_abort( $old );
 602                         } );
 603                 }
 604
 605                 return null;
 606         }
 607
 608         function __destruct() {
 609                 $this->destroy();
 610         }
 611 }
 612
 613 class_alias( LBFactory::class, 'LBFactory' );