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 Psr\Log\NullLogger;
  28 use Wikimedia\ScopedCallback;
  29 use BagOStuff;
  30 use EmptyBagOStuff;
  31 use WANObjectCache;
  32 use Exception;
  33 use RuntimeException;
  34 use LogicException;
  35
  36 /**
  37  * An interface for generating database load balancers
  38  * @ingroup Database
  39  */
  40 abstract class LBFactory implements ILBFactory {
  41         /** @var ChronologyProtector */
  42         private $chronProt;
  43         /** @var object|string Class name or object With profileIn/profileOut methods */
  44         private $profiler;
  45         /** @var TransactionProfiler */
  46         private $trxProfiler;
  47         /** @var LoggerInterface */
  48         private $replLogger;
  49         /** @var LoggerInterface */
  50         private $connLogger;
  51         /** @var LoggerInterface */
  52         private $queryLogger;
  53         /** @var LoggerInterface */
  54         private $perfLogger;
  55         /** @var callable Error logger */
  56         private $errorLogger;
  57         /** @var callable Deprecation logger */
  58         private $deprecationLogger;
  59
  60         /** @var BagOStuff */
  61         protected $srvCache;
  62         /** @var BagOStuff */
  63         protected $memStash;
  64         /** @var WANObjectCache */
  65         protected $wanCache;
  66
  67         /** @var DatabaseDomain Local domain */
  68         protected $localDomain;
  69
  70         /** @var string Local hostname of the app server */
  71         private $hostname;
  72         /** @var array Web request information about the client */
  73         private $requestInfo;
  74         /** @var bool Whether this PHP instance is for a CLI script */
  75         private $cliMode;
  76         /** @var string Agent name for query profiling */
  77         private $agent;
  78         /** @var string Secret string for HMAC hashing */
  79         private $secret;
  80
  81         /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
  82         private $tableAliases = [];
  83         /** @var string[] Map of (index alias => index) */
  84         private $indexAliases = [];
  85         /** @var callable[] */
  86         private $replicationWaitCallbacks = [];
  87
  88         /** @var mixed */
  89         private $ticket;
  90         /** @var string|bool String if a requested DBO_TRX transaction round is active */
  91         private $trxRoundId = false;
  92         /** @var string One of the ROUND_* class constants */
  93         private $trxRoundStage = self::ROUND_CURSORY;
  94
  95         /** @var string|bool Reason all LBs are read-only or false if not */
  96         protected $readOnlyReason = false;
  97
  98         /** @var string|null */
  99         private $defaultGroup = null;
 100
 101         /** @var int|null */
 102         protected $maxLag;
 103
 104         const ROUND_CURSORY = 'cursory';
 105         const ROUND_BEGINNING = 'within-begin';
 106         const ROUND_COMMITTING = 'within-commit';
 107         const ROUND_ROLLING_BACK = 'within-rollback';
 108         const ROUND_COMMIT_CALLBACKS = 'within-commit-callbacks';
 109         const ROUND_ROLLBACK_CALLBACKS = 'within-rollback-callbacks';
 110
 111         private static $loggerFields =
 112                 [ 'replLogger', 'connLogger', 'queryLogger', 'perfLogger' ];
 113
 114         public function __construct( array $conf ) {
 115                 $this->localDomain = isset( $conf['localDomain'] )
 116                         ? DatabaseDomain::newFromId( $conf['localDomain'] )
 117                         : DatabaseDomain::newUnspecified();
 118
 119                 $this->maxLag = $conf['maxLag'] ?? null;
 120                 if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
 121                         $this->readOnlyReason = $conf['readOnlyReason'];
 122                 }
 123
 124                 $this->srvCache = $conf['srvCache'] ?? new EmptyBagOStuff();
 125                 $this->memStash = $conf['memStash'] ?? new EmptyBagOStuff();
 126                 $this->wanCache = $conf['wanCache'] ?? WANObjectCache::newEmpty();
 127
 128                 foreach ( self::$loggerFields as $key ) {
 129                         $this->$key = $conf[$key] ?? new NullLogger();
 130                 }
 131                 $this->errorLogger = $conf['errorLogger'] ?? function ( Exception $e ) {
 132                         trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
 133                 };
 134                 $this->deprecationLogger = $conf['deprecationLogger'] ?? function ( $msg ) {
 135                         trigger_error( $msg, E_USER_DEPRECATED );
 136                 };
 137
 138                 $this->profiler = $conf['profiler'] ?? null;
 139                 $this->trxProfiler = $conf['trxProfiler'] ?? new TransactionProfiler();
 140
 141                 $this->requestInfo = [
 142                         'IPAddress' => $_SERVER[ 'REMOTE_ADDR' ] ?? '',
 143                         'UserAgent' => $_SERVER['HTTP_USER_AGENT'] ?? '',
 144                         // Headers application can inject via LBFactory::setRequestInfo()
 145                         'ChronologyProtection' => null,
 146                         'ChronologyClientId' => null, // prior $cpClientId value from LBFactory::shutdown()
 147                         'ChronologyPositionIndex' => null // prior $cpIndex value from LBFactory::shutdown()
 148                 ];
 149
 150                 $this->cliMode = $conf['cliMode'] ?? ( PHP_SAPI === 'cli' || PHP_SAPI === 'phpdbg' );
 151                 $this->hostname = $conf['hostname'] ?? gethostname();
 152                 $this->agent = $conf['agent'] ?? '';
 153                 $this->defaultGroup = $conf['defaultGroup'] ?? null;
 154                 $this->secret = $conf['secret'] ?? '';
 155
 156                 $this->ticket = mt_rand();
 157         }
 158
 159         public function destroy() {
 160                 $this->shutdown( self::SHUTDOWN_NO_CHRONPROT );
 161                 $this->forEachLBCallMethod( 'disable' );
 162         }
 163
 164         public function getLocalDomainID() {
 165                 return $this->localDomain->getId();
 166         }
 167
 168         public function resolveDomainID( $domain ) {
 169                 return ( $domain !== false ) ? (string)$domain : $this->getLocalDomainID();
 170         }
 171
 172         public function shutdown(
 173                 $mode = self::SHUTDOWN_CHRONPROT_SYNC,
 174                 callable $workCallback = null,
 175                 &$cpIndex = null,
 176                 &$cpClientId = null
 177         ) {
 178                 $chronProt = $this->getChronologyProtector();
 179                 if ( $mode === self::SHUTDOWN_CHRONPROT_SYNC ) {
 180                         $this->shutdownChronologyProtector( $chronProt, $workCallback, 'sync', $cpIndex );
 181                 } elseif ( $mode === self::SHUTDOWN_CHRONPROT_ASYNC ) {
 182                         $this->shutdownChronologyProtector( $chronProt, null, 'async', $cpIndex );
 183                 }
 184
 185                 $cpClientId = $chronProt->getClientId();
 186
 187                 $this->commitMasterChanges( __METHOD__ ); // sanity
 188         }
 189
 190         /**
 191          * @see ILBFactory::newMainLB()
 192          * @param bool $domain
 193          * @return ILoadBalancer
 194          */
 195         abstract public function newMainLB( $domain = false );
 196
 197         /**
 198          * @see ILBFactory::getMainLB()
 199          * @param bool $domain
 200          * @return ILoadBalancer
 201          */
 202         abstract public function getMainLB( $domain = false );
 203
 204         /**
 205          * @see ILBFactory::newExternalLB()
 206          * @param string $cluster
 207          * @return ILoadBalancer
 208          */
 209         abstract public function newExternalLB( $cluster );
 210
 211         /**
 212          * @see ILBFactory::getExternalLB()
 213          * @param string $cluster
 214          * @return ILoadBalancer
 215          */
 216         abstract public function getExternalLB( $cluster );
 217
 218         /**
 219          * Call a method of each tracked load balancer
 220          *
 221          * @param string $methodName
 222          * @param array $args
 223          */
 224         protected function forEachLBCallMethod( $methodName, array $args = [] ) {
 225                 $this->forEachLB(
 226                         function ( ILoadBalancer $loadBalancer, $methodName, array $args ) {
 227                                 $loadBalancer->$methodName( ...$args );
 228                         },
 229                         [ $methodName, $args ]
 230                 );
 231         }
 232
 233         public function flushReplicaSnapshots( $fname = __METHOD__ ) {
 234                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 235         }
 236
 237         final public function commitAll( $fname = __METHOD__, array $options = [] ) {
 238                 $this->commitMasterChanges( $fname, $options );
 239                 $this->forEachLBCallMethod( 'flushMasterSnapshots', [ $fname ] );
 240                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 241         }
 242
 243         final public function beginMasterChanges( $fname = __METHOD__ ) {
 244                 $this->assertTransactionRoundStage( self::ROUND_CURSORY );
 245                 $this->trxRoundStage = self::ROUND_BEGINNING;
 246                 if ( $this->trxRoundId !== false ) {
 247                         throw new DBTransactionError(
 248                                 null,
 249                                 "$fname: transaction round '{$this->trxRoundId}' already started."
 250                         );
 251                 }
 252                 $this->trxRoundId = $fname;
 253                 // Set DBO_TRX flags on all appropriate DBs
 254                 $this->forEachLBCallMethod( 'beginMasterChanges', [ $fname ] );
 255                 $this->trxRoundStage = self::ROUND_CURSORY;
 256         }
 257
 258         final public function commitMasterChanges( $fname = __METHOD__, array $options = [] ) {
 259                 $this->assertTransactionRoundStage( self::ROUND_CURSORY );
 260                 $this->trxRoundStage = self::ROUND_COMMITTING;
 261                 if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
 262                         throw new DBTransactionError(
 263                                 null,
 264                                 "$fname: transaction round '{$this->trxRoundId}' still running."
 265                         );
 266                 }
 267                 /** @noinspection PhpUnusedLocalVariableInspection */
 268                 $scope = ScopedCallback::newScopedIgnoreUserAbort(); // try to ignore client aborts
 269                 // Run pre-commit callbacks and suppress post-commit callbacks, aborting on failure
 270                 do {
 271                         $count = 0; // number of callbacks executed this iteration
 272                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$count ) {
 273                                 $count += $lb->finalizeMasterChanges();
 274                         } );
 275                 } while ( $count > 0 );
 276                 $this->trxRoundId = false;
 277                 // Perform pre-commit checks, aborting on failure
 278                 $this->forEachLBCallMethod( 'approveMasterChanges', [ $options ] );
 279                 // Log the DBs and methods involved in multi-DB transactions
 280                 $this->logIfMultiDbTransaction();
 281                 // Actually perform the commit on all master DB connections and revert DBO_TRX
 282                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 283                 // Run all post-commit callbacks in a separate step
 284                 $this->trxRoundStage = self::ROUND_COMMIT_CALLBACKS;
 285                 $e = $this->executePostTransactionCallbacks();
 286                 $this->trxRoundStage = self::ROUND_CURSORY;
 287                 // Throw any last post-commit callback error
 288                 if ( $e instanceof Exception ) {
 289                         throw $e;
 290                 }
 291         }
 292
 293         final public function rollbackMasterChanges( $fname = __METHOD__ ) {
 294                 $this->trxRoundStage = self::ROUND_ROLLING_BACK;
 295                 $this->trxRoundId = false;
 296                 // Actually perform the rollback on all master DB connections and revert DBO_TRX
 297                 $this->forEachLBCallMethod( 'rollbackMasterChanges', [ $fname ] );
 298                 // Run all post-commit callbacks in a separate step
 299                 $this->trxRoundStage = self::ROUND_ROLLBACK_CALLBACKS;
 300                 $this->executePostTransactionCallbacks();
 301                 $this->trxRoundStage = self::ROUND_CURSORY;
 302         }
 303
 304         /**
 305          * @return Exception|null
 306          */
 307         private function executePostTransactionCallbacks() {
 308                 // Run all post-commit callbacks until new ones stop getting added
 309                 $e = null; // first callback exception
 310                 do {
 311                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 312                                 $ex = $lb->runMasterTransactionIdleCallbacks();
 313                                 $e = $e ?: $ex;
 314                         } );
 315                 } while ( $this->hasMasterChanges() );
 316                 // Run all listener callbacks once
 317                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 318                         $ex = $lb->runMasterTransactionListenerCallbacks();
 319                         $e = $e ?: $ex;
 320                 } );
 321
 322                 return $e;
 323         }
 324
 325         public function hasTransactionRound() {
 326                 return ( $this->trxRoundId !== false );
 327         }
 328
 329         public function isReadyForRoundOperations() {
 330                 return ( $this->trxRoundStage === self::ROUND_CURSORY );
 331         }
 332
 333         /**
 334          * Log query info if multi DB transactions are going to be committed now
 335          */
 336         private function logIfMultiDbTransaction() {
 337                 $callersByDB = [];
 338                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$callersByDB ) {
 339                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 340                         $callers = $lb->pendingMasterChangeCallers();
 341                         if ( $callers ) {
 342                                 $callersByDB[$masterName] = $callers;
 343                         }
 344                 } );
 345
 346                 if ( count( $callersByDB ) >= 2 ) {
 347                         $dbs = implode( ', ', array_keys( $callersByDB ) );
 348                         $msg = "Multi-DB transaction [{$dbs}]:\n";
 349                         foreach ( $callersByDB as $db => $callers ) {
 350                                 $msg .= "$db: " . implode( '; ', $callers ) . "\n";
 351                         }
 352                         $this->queryLogger->info( $msg );
 353                 }
 354         }
 355
 356         public function hasMasterChanges() {
 357                 $ret = false;
 358                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 359                         $ret = $ret || $lb->hasMasterChanges();
 360                 } );
 361
 362                 return $ret;
 363         }
 364
 365         public function laggedReplicaUsed() {
 366                 $ret = false;
 367                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 368                         $ret = $ret || $lb->laggedReplicaUsed();
 369                 } );
 370
 371                 return $ret;
 372         }
 373
 374         public function hasOrMadeRecentMasterChanges( $age = null ) {
 375                 $ret = false;
 376                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $age, &$ret ) {
 377                         $ret = $ret || $lb->hasOrMadeRecentMasterChanges( $age );
 378                 } );
 379                 return $ret;
 380         }
 381
 382         public function waitForReplication( array $opts = [] ) {
 383                 $opts += [
 384                         'domain' => false,
 385                         'cluster' => false,
 386                         'timeout' => $this->cliMode ? 60 : 1,
 387                         'ifWritesSince' => null
 388                 ];
 389
 390                 if ( $opts['domain'] === false && isset( $opts['wiki'] ) ) {
 391                         $opts['domain'] = $opts['wiki']; // b/c
 392                 }
 393
 394                 // Figure out which clusters need to be checked
 395                 /** @var ILoadBalancer[] $lbs */
 396                 $lbs = [];
 397                 if ( $opts['cluster'] !== false ) {
 398                         $lbs[] = $this->getExternalLB( $opts['cluster'] );
 399                 } elseif ( $opts['domain'] !== false ) {
 400                         $lbs[] = $this->getMainLB( $opts['domain'] );
 401                 } else {
 402                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$lbs ) {
 403                                 $lbs[] = $lb;
 404                         } );
 405                         if ( !$lbs ) {
 406                                 return true; // nothing actually used
 407                         }
 408                 }
 409
 410                 // Get all the master positions of applicable DBs right now.
 411                 // This can be faster since waiting on one cluster reduces the
 412                 // time needed to wait on the next clusters.
 413                 $masterPositions = array_fill( 0, count( $lbs ), false );
 414                 foreach ( $lbs as $i => $lb ) {
 415                         if ( $lb->getServerCount() <= 1 ) {
 416                                 // T29975 - Don't try to wait for replica DBs if there are none
 417                                 // Prevents permission error when getting master position
 418                                 continue;
 419                         } elseif ( $opts['ifWritesSince']
 420                                 && $lb->lastMasterChangeTimestamp() < $opts['ifWritesSince']
 421                         ) {
 422                                 continue; // no writes since the last wait
 423                         }
 424                         $masterPositions[$i] = $lb->getMasterPos();
 425                 }
 426
 427                 // Run any listener callbacks *after* getting the DB positions. The more
 428                 // time spent in the callbacks, the less time is spent in waitForAll().
 429                 foreach ( $this->replicationWaitCallbacks as $callback ) {
 430                         $callback();
 431                 }
 432
 433                 $failed = [];
 434                 foreach ( $lbs as $i => $lb ) {
 435                         if ( $masterPositions[$i] ) {
 436                                 // The RDBMS may not support getMasterPos()
 437                                 if ( !$lb->waitForAll( $masterPositions[$i], $opts['timeout'] ) ) {
 438                                         $failed[] = $lb->getServerName( $lb->getWriterIndex() );
 439                                 }
 440                         }
 441                 }
 442
 443                 return !$failed;
 444         }
 445
 446         public function setWaitForReplicationListener( $name, callable $callback = null ) {
 447                 if ( $callback ) {
 448                         $this->replicationWaitCallbacks[$name] = $callback;
 449                 } else {
 450                         unset( $this->replicationWaitCallbacks[$name] );
 451                 }
 452         }
 453
 454         public function getEmptyTransactionTicket( $fname ) {
 455                 if ( $this->hasMasterChanges() ) {
 456                         $this->queryLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 457                                 ( new RuntimeException() )->getTraceAsString() );
 458
 459                         return null;
 460                 }
 461
 462                 return $this->ticket;
 463         }
 464
 465         final public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
 466                 if ( $ticket !== $this->ticket ) {
 467                         $this->perfLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 468                                 ( new RuntimeException() )->getTraceAsString() );
 469
 470                         return false;
 471                 }
 472
 473                 // The transaction owner and any caller with the empty transaction ticket can commit
 474                 // so that getEmptyTransactionTicket() callers don't risk seeing DBTransactionError.
 475                 if ( $this->trxRoundId !== false && $fname !== $this->trxRoundId ) {
 476                         $this->queryLogger->info( "$fname: committing on behalf of {$this->trxRoundId}." );
 477                         $fnameEffective = $this->trxRoundId;
 478                 } else {
 479                         $fnameEffective = $fname;
 480                 }
 481
 482                 $this->commitMasterChanges( $fnameEffective );
 483                 $waitSucceeded = $this->waitForReplication( $opts );
 484                 // If a nested caller committed on behalf of $fname, start another empty $fname
 485                 // transaction, leaving the caller with the same empty transaction state as before.
 486                 if ( $fnameEffective !== $fname ) {
 487                         $this->beginMasterChanges( $fnameEffective );
 488                 }
 489
 490                 return $waitSucceeded;
 491         }
 492
 493         public function getChronologyProtectorTouched( $dbName ) {
 494                 return $this->getChronologyProtector()->getTouched( $dbName );
 495         }
 496
 497         public function disableChronologyProtection() {
 498                 $this->getChronologyProtector()->setEnabled( false );
 499         }
 500
 501         /**
 502          * @return ChronologyProtector
 503          */
 504         protected function getChronologyProtector() {
 505                 if ( $this->chronProt ) {
 506                         return $this->chronProt;
 507                 }
 508
 509                 $this->chronProt = new ChronologyProtector(
 510                         $this->memStash,
 511                         [
 512                                 'ip' => $this->requestInfo['IPAddress'],
 513                                 'agent' => $this->requestInfo['UserAgent'],
 514                                 'clientId' => $this->requestInfo['ChronologyClientId'] ?: null
 515                         ],
 516                         $this->requestInfo['ChronologyPositionIndex'],
 517                         $this->secret
 518                 );
 519                 $this->chronProt->setLogger( $this->replLogger );
 520
 521                 if ( $this->cliMode ) {
 522                         $this->chronProt->setEnabled( false );
 523                 } elseif ( $this->requestInfo['ChronologyProtection'] === 'false' ) {
 524                         // Request opted out of using position wait logic. This is useful for requests
 525                         // done by the job queue or background ETL that do not have a meaningful session.
 526                         $this->chronProt->setWaitEnabled( false );
 527                 } elseif ( $this->memStash instanceof EmptyBagOStuff ) {
 528                         // No where to store any DB positions and wait for them to appear
 529                         $this->chronProt->setEnabled( false );
 530                         $this->replLogger->info( 'Cannot use ChronologyProtector with EmptyBagOStuff.' );
 531                 }
 532
 533                 $this->replLogger->debug( __METHOD__ . ': using request info ' .
 534                         json_encode( $this->requestInfo, JSON_PRETTY_PRINT ) );
 535
 536                 return $this->chronProt;
 537         }
 538
 539         /**
 540          * Get and record all of the staged DB positions into persistent memory storage
 541          *
 542          * @param ChronologyProtector $cp
 543          * @param callable|null $workCallback Work to do instead of waiting on syncing positions
 544          * @param string $mode One of (sync, async); whether to wait on remote datacenters
 545          * @param int|null &$cpIndex DB position key write counter; incremented on update
 546          */
 547         protected function shutdownChronologyProtector(
 548                 ChronologyProtector $cp, $workCallback, $mode, &$cpIndex = null
 549         ) {
 550                 // Record all the master positions needed
 551                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $cp ) {
 552                         $cp->storeSessionReplicationPosition( $lb );
 553                 } );
 554                 // Write them to the persistent stash. Try to do something useful by running $work
 555                 // while ChronologyProtector waits for the stash write to replicate to all DCs.
 556                 $unsavedPositions = $cp->shutdown( $workCallback, $mode, $cpIndex );
 557                 if ( $unsavedPositions && $workCallback ) {
 558                         // Invoke callback in case it did not cache the result yet
 559                         $workCallback(); // work now to block for less time in waitForAll()
 560                 }
 561                 // If the positions failed to write to the stash, at least wait on local datacenter
 562                 // replica DBs to catch up before responding. Even if there are several DCs, this increases
 563                 // the chance that the user will see their own changes immediately afterwards. As long
 564                 // as the sticky DC cookie applies (same domain), this is not even an issue.
 565                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $unsavedPositions ) {
 566                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 567                         if ( isset( $unsavedPositions[$masterName] ) ) {
 568                                 $lb->waitForAll( $unsavedPositions[$masterName] );
 569                         }
 570                 } );
 571         }
 572
 573         /**
 574          * Base parameters to ILoadBalancer::__construct()
 575          * @return array
 576          */
 577         final protected function baseLoadBalancerParams() {
 578                 if ( $this->trxRoundStage === self::ROUND_COMMIT_CALLBACKS ) {
 579                         $initStage = ILoadBalancer::STAGE_POSTCOMMIT_CALLBACKS;
 580                 } elseif ( $this->trxRoundStage === self::ROUND_ROLLBACK_CALLBACKS ) {
 581                         $initStage = ILoadBalancer::STAGE_POSTROLLBACK_CALLBACKS;
 582                 } else {
 583                         $initStage = null;
 584                 }
 585
 586                 return [
 587                         'localDomain' => $this->localDomain,
 588                         'readOnlyReason' => $this->readOnlyReason,
 589                         'srvCache' => $this->srvCache,
 590                         'wanCache' => $this->wanCache,
 591                         'profiler' => $this->profiler,
 592                         'trxProfiler' => $this->trxProfiler,
 593                         'queryLogger' => $this->queryLogger,
 594                         'connLogger' => $this->connLogger,
 595                         'replLogger' => $this->replLogger,
 596                         'errorLogger' => $this->errorLogger,
 597                         'deprecationLogger' => $this->deprecationLogger,
 598                         'hostname' => $this->hostname,
 599                         'cliMode' => $this->cliMode,
 600                         'agent' => $this->agent,
 601                         'maxLag' => $this->maxLag,
 602                         'defaultGroup' => $this->defaultGroup,
 603                         'chronologyCallback' => function ( ILoadBalancer $lb ) {
 604                                 // Defer ChronologyProtector construction in case setRequestInfo() ends up
 605                                 // being called later (but before the first connection attempt) (T192611)
 606                                 $this->getChronologyProtector()->applySessionReplicationPosition( $lb );
 607                         },
 608                         'roundStage' => $initStage
 609                 ];
 610         }
 611
 612         /**
 613          * @param ILoadBalancer $lb
 614          */
 615         protected function initLoadBalancer( ILoadBalancer $lb ) {
 616                 if ( $this->trxRoundId !== false ) {
 617                         $lb->beginMasterChanges( $this->trxRoundId ); // set DBO_TRX
 618                 }
 619
 620                 $lb->setTableAliases( $this->tableAliases );
 621                 $lb->setIndexAliases( $this->indexAliases );
 622         }
 623
 624         public function setTableAliases( array $aliases ) {
 625                 $this->tableAliases = $aliases;
 626         }
 627
 628         public function setIndexAliases( array $aliases ) {
 629                 $this->indexAliases = $aliases;
 630         }
 631
 632         /**
 633          * @param string $prefix
 634          * @deprecated Since 1.33
 635          */
 636         public function setDomainPrefix( $prefix ) {
 637                 $this->setLocalDomainPrefix( $prefix );
 638         }
 639
 640         public function setLocalDomainPrefix( $prefix ) {
 641                 $this->localDomain = new DatabaseDomain(
 642                         $this->localDomain->getDatabase(),
 643                         $this->localDomain->getSchema(),
 644                         $prefix
 645                 );
 646
 647                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $prefix ) {
 648                         $lb->setLocalDomainPrefix( $prefix );
 649                 } );
 650         }
 651
 652         public function redefineLocalDomain( $domain ) {
 653                 $this->closeAll();
 654
 655                 $this->localDomain = DatabaseDomain::newFromId( $domain );
 656
 657                 $this->forEachLB( function ( ILoadBalancer $lb ) {
 658                         $lb->redefineLocalDomain( $this->localDomain );
 659                 } );
 660         }
 661
 662         public function closeAll() {
 663                 $this->forEachLBCallMethod( 'closeAll' );
 664         }
 665
 666         public function setAgentName( $agent ) {
 667                 $this->agent = $agent;
 668         }
 669
 670         public function appendShutdownCPIndexAsQuery( $url, $index ) {
 671                 $usedCluster = 0;
 672                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$usedCluster ) {
 673                         $usedCluster |= ( $lb->getServerCount() > 1 );
 674                 } );
 675
 676                 if ( !$usedCluster ) {
 677                         return $url; // no master/replica clusters touched
 678                 }
 679
 680                 return strpos( $url, '?' ) === false ? "$url?cpPosIndex=$index" : "$url&cpPosIndex=$index";
 681         }
 682
 683         public function getChronologyProtectorClientId() {
 684                 return $this->getChronologyProtector()->getClientId();
 685         }
 686
 687         /**
 688          * @param int $index Write index
 689          * @param int $time UNIX timestamp; can be used to detect stale cookies (T190082)
 690          * @param string $clientId Agent ID hash from ILBFactory::shutdown()
 691          * @return string Timestamp-qualified write index of the form "<index>@<timestamp>#<hash>"
 692          * @since 1.32
 693          */
 694         public static function makeCookieValueFromCPIndex( $index, $time, $clientId ) {
 695                 return "$index@$time#$clientId";
 696         }
 697
 698         /**
 699          * @param string $value Possible result of LBFactory::makeCookieValueFromCPIndex()
 700          * @param int $minTimestamp Lowest UNIX timestamp that a non-expired value can have
 701          * @return array (index: int or null, clientId: string or null)
 702          * @since 1.32
 703          */
 704         public static function getCPInfoFromCookieValue( $value, $minTimestamp ) {
 705                 static $placeholder = [ 'index' => null, 'clientId' => null ];
 706
 707                 if ( !preg_match( '/^(\d+)@(\d+)#([0-9a-f]{32})$/', $value, $m ) ) {
 708                         return $placeholder; // invalid
 709                 }
 710
 711                 $index = (int)$m[1];
 712                 if ( $index <= 0 ) {
 713                         return $placeholder; // invalid
 714                 } elseif ( isset( $m[2] ) && $m[2] !== '' && (int)$m[2] < $minTimestamp ) {
 715                         return $placeholder; // expired
 716                 }
 717
 718                 $clientId = ( isset( $m[3] ) && $m[3] !== '' ) ? $m[3] : null;
 719
 720                 return [ 'index' => $index, 'clientId' => $clientId ];
 721         }
 722
 723         public function setRequestInfo( array $info ) {
 724                 if ( $this->chronProt ) {
 725                         throw new LogicException( 'ChronologyProtector already initialized.' );
 726                 }
 727
 728                 $this->requestInfo = $info + $this->requestInfo;
 729         }
 730
 731         /**
 732          * @param string $stage
 733          */
 734         private function assertTransactionRoundStage( $stage ) {
 735                 if ( $this->trxRoundStage !== $stage ) {
 736                         throw new DBTransactionError(
 737                                 null,
 738                                 "Transaction round stage must be '$stage' (not '{$this->trxRoundStage}')"
 739                         );
 740                 }
 741         }
 742
 743         function __destruct() {
 744                 $this->destroy();
 745         }
 746 }