includes/db/DatabaseMysqlBase.php

   1 <?php
   2 /**
   3  * This is the MySQL database abstraction layer.
   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 /**
  25  * Database abstraction object for MySQL.
  26  * Defines methods independent on used MySQL extension.
  27  *
  28  * @ingroup Database
  29  * @since 1.22
  30  * @see Database
  31  */
  32 abstract class DatabaseMysqlBase extends DatabaseBase {
  33         /** @var MysqlMasterPos */
  34         protected $lastKnownSlavePos;
  35
  36         /**
  37          * @return string
  38          */
  39         function getType() {
  40                 return 'mysql';
  41         }
  42
  43         /**
  44          * @param $server string
  45          * @param $user string
  46          * @param $password string
  47          * @param $dbName string
  48          * @return bool
  49          * @throws DBConnectionError
  50          */
  51         function open( $server, $user, $password, $dbName ) {
  52                 global $wgAllDBsAreLocalhost, $wgDBmysql5, $wgSQLMode;
  53                 wfProfileIn( __METHOD__ );
  54
  55                 # Debugging hack -- fake cluster
  56                 if ( $wgAllDBsAreLocalhost ) {
  57                         $realServer = 'localhost';
  58                 } else {
  59                         $realServer = $server;
  60                 }
  61                 $this->close();
  62                 $this->mServer = $server;
  63                 $this->mUser = $user;
  64                 $this->mPassword = $password;
  65                 $this->mDBname = $dbName;
  66
  67                 wfProfileIn( "dbconnect-$server" );
  68
  69                 # The kernel's default SYN retransmission period is far too slow for us,
  70                 # so we use a short timeout plus a manual retry. Retrying means that a small
  71                 # but finite rate of SYN packet loss won't cause user-visible errors.
  72                 $this->mConn = false;
  73                 $this->installErrorHandler();
  74                 try {
  75                         $this->mConn = $this->mysqlConnect( $realServer );
  76                 } catch ( Exception $ex ) {
  77                         wfProfileOut( "dbconnect-$server" );
  78                         wfProfileOut( __METHOD__ );
  79                         $this->restoreErrorHandler();
  80                         throw $ex;
  81                 }
  82                 $error = $this->restoreErrorHandler();
  83
  84                 wfProfileOut( "dbconnect-$server" );
  85
  86                 # Always log connection errors
  87                 if ( !$this->mConn ) {
  88                         if ( !$error ) {
  89                                 $error = $this->lastError();
  90                         }
  91                         wfLogDBError( "Error connecting to {$this->mServer}: $error\n" );
  92                         wfDebug( "DB connection error\n" .
  93                                 "Server: $server, User: $user, Password: " .
  94                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
  95
  96                         wfProfileOut( __METHOD__ );
  97
  98                         return $this->reportConnectionError( $error );
  99                 }
 100
 101                 if ( $dbName != '' ) {
 102                         wfSuppressWarnings();
 103                         $success = $this->selectDB( $dbName );
 104                         wfRestoreWarnings();
 105                         if ( !$success ) {
 106                                 wfLogDBError( "Error selecting database $dbName on server {$this->mServer}\n" );
 107                                 wfDebug( "Error selecting database $dbName on server {$this->mServer} " .
 108                                         "from client host " . wfHostname() . "\n" );
 109
 110                                 wfProfileOut( __METHOD__ );
 111
 112                                 return $this->reportConnectionError( "Error selecting database $dbName" );
 113                         }
 114                 }
 115
 116                 // Tell the server we're communicating with it in UTF-8.
 117                 // This may engage various charset conversions.
 118                 if ( $wgDBmysql5 ) {
 119                         $this->mysqlSetCharset( 'utf8' );
 120                 } else {
 121                         $this->mysqlSetCharset( 'binary' );
 122                 }
 123                 // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 124                 if ( is_string( $wgSQLMode ) ) {
 125                         $mode = $this->addQuotes( $wgSQLMode );
 126                         $this->query( "SET sql_mode = $mode", __METHOD__ );
 127                 }
 128
 129                 $this->mOpened = true;
 130                 wfProfileOut( __METHOD__ );
 131
 132                 return true;
 133         }
 134
 135         /**
 136          * Open a connection to a MySQL server
 137          *
 138          * @param $realServer string
 139          * @return mixed Raw connection
 140          * @throws DBConnectionError
 141          */
 142         abstract protected function mysqlConnect( $realServer );
 143
 144         /**
 145          * Set the character set of the MySQL link
 146          *
 147          * @param string $charset
 148          * @return bool
 149          */
 150         abstract protected function mysqlSetCharset( $charset );
 151
 152         /**
 153          * @param $res ResultWrapper
 154          * @throws DBUnexpectedError
 155          */
 156         function freeResult( $res ) {
 157                 if ( $res instanceof ResultWrapper ) {
 158                         $res = $res->result;
 159                 }
 160                 wfSuppressWarnings();
 161                 $ok = $this->mysqlFreeResult( $res );
 162                 wfRestoreWarnings();
 163                 if ( !$ok ) {
 164                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 165                 }
 166         }
 167
 168         /**
 169          * Free result memory
 170          *
 171          * @param $res Raw result
 172          * @return bool
 173          */
 174         abstract protected function mysqlFreeResult( $res );
 175
 176         /**
 177          * @param $res ResultWrapper
 178          * @return object|bool
 179          * @throws DBUnexpectedError
 180          */
 181         function fetchObject( $res ) {
 182                 if ( $res instanceof ResultWrapper ) {
 183                         $res = $res->result;
 184                 }
 185                 wfSuppressWarnings();
 186                 $row = $this->mysqlFetchObject( $res );
 187                 wfRestoreWarnings();
 188
 189                 $errno = $this->lastErrno();
 190                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 191                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 192                 // these are the only errors mysql_fetch_object can cause.
 193                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 194                 if ( $errno == 2000 || $errno == 2013 ) {
 195                         throw new DBUnexpectedError( $this, 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() ) );
 196                 }
 197
 198                 return $row;
 199         }
 200
 201         /**
 202          * Fetch a result row as an object
 203          *
 204          * @param $res Raw result
 205          * @return stdClass
 206          */
 207         abstract protected function mysqlFetchObject( $res );
 208
 209         /**
 210          * @param $res ResultWrapper
 211          * @return array|bool
 212          * @throws DBUnexpectedError
 213          */
 214         function fetchRow( $res ) {
 215                 if ( $res instanceof ResultWrapper ) {
 216                         $res = $res->result;
 217                 }
 218                 wfSuppressWarnings();
 219                 $row = $this->mysqlFetchArray( $res );
 220                 wfRestoreWarnings();
 221
 222                 $errno = $this->lastErrno();
 223                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 224                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 225                 // these are the only errors mysql_fetch_array can cause.
 226                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 227                 if ( $errno == 2000 || $errno == 2013 ) {
 228                         throw new DBUnexpectedError( $this, 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() ) );
 229                 }
 230
 231                 return $row;
 232         }
 233
 234         /**
 235          * Fetch a result row as an associative and numeric array
 236          *
 237          * @param $res Raw result
 238          * @return array
 239          */
 240         abstract protected function mysqlFetchArray( $res );
 241
 242         /**
 243          * @throws DBUnexpectedError
 244          * @param $res ResultWrapper
 245          * @return int
 246          */
 247         function numRows( $res ) {
 248                 if ( $res instanceof ResultWrapper ) {
 249                         $res = $res->result;
 250                 }
 251                 wfSuppressWarnings();
 252                 $n = $this->mysqlNumRows( $res );
 253                 wfRestoreWarnings();
 254
 255                 // Unfortunately, mysql_num_rows does not reset the last errno.
 256                 // We are not checking for any errors here, since
 257                 // these are no errors mysql_num_rows can cause.
 258                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 259                 // See https://bugzilla.wikimedia.org/42430
 260                 return $n;
 261         }
 262
 263         /**
 264          * Get number of rows in result
 265          *
 266          * @param $res Raw result
 267          * @return int
 268          */
 269         abstract protected function mysqlNumRows( $res );
 270
 271         /**
 272          * @param $res ResultWrapper
 273          * @return int
 274          */
 275         function numFields( $res ) {
 276                 if ( $res instanceof ResultWrapper ) {
 277                         $res = $res->result;
 278                 }
 279
 280                 return $this->mysqlNumFields( $res );
 281         }
 282
 283         /**
 284          * Get number of fields in result
 285          *
 286          * @param $res Raw result
 287          * @return int
 288          */
 289         abstract protected function mysqlNumFields( $res );
 290
 291         /**
 292          * @param $res ResultWrapper
 293          * @param $n string
 294          * @return string
 295          */
 296         function fieldName( $res, $n ) {
 297                 if ( $res instanceof ResultWrapper ) {
 298                         $res = $res->result;
 299                 }
 300
 301                 return $this->mysqlFieldName( $res, $n );
 302         }
 303
 304         /**
 305          * Get the name of the specified field in a result
 306          *
 307          * @param $res Raw result
 308          * @param $n int
 309          * @return string
 310          */
 311         abstract protected function mysqlFieldName( $res, $n );
 312
 313         /**
 314          * @param $res ResultWrapper
 315          * @param $row
 316          * @return bool
 317          */
 318         function dataSeek( $res, $row ) {
 319                 if ( $res instanceof ResultWrapper ) {
 320                         $res = $res->result;
 321                 }
 322
 323                 return $this->mysqlDataSeek( $res, $row );
 324         }
 325
 326         /**
 327          * Move internal result pointer
 328          *
 329          * @param $res Raw result
 330          * @param $row int
 331          * @return bool
 332          */
 333         abstract protected function mysqlDataSeek( $res, $row );
 334
 335         /**
 336          * @return string
 337          */
 338         function lastError() {
 339                 if ( $this->mConn ) {
 340                         # Even if it's non-zero, it can still be invalid
 341                         wfSuppressWarnings();
 342                         $error = $this->mysqlError( $this->mConn );
 343                         if ( !$error ) {
 344                                 $error = $this->mysqlError();
 345                         }
 346                         wfRestoreWarnings();
 347                 } else {
 348                         $error = $this->mysqlError();
 349                 }
 350                 if ( $error ) {
 351                         $error .= ' (' . $this->mServer . ')';
 352                 }
 353
 354                 return $error;
 355         }
 356
 357         /**
 358          * Returns the text of the error message from previous MySQL operation
 359          *
 360          * @param $conn Raw connection
 361          * @return string
 362          */
 363         abstract protected function mysqlError( $conn = null );
 364
 365         /**
 366          * @param $table string
 367          * @param $uniqueIndexes
 368          * @param $rows array
 369          * @param $fname string
 370          * @return ResultWrapper
 371          */
 372         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 373                 return $this->nativeReplace( $table, $rows, $fname );
 374         }
 375
 376         /**
 377          * Estimate rows in dataset
 378          * Returns estimated count, based on EXPLAIN output
 379          * Takes same arguments as Database::select()
 380          *
 381          * @param $table string|array
 382          * @param $vars string|array
 383          * @param $conds string|array
 384          * @param $fname string
 385          * @param $options string|array
 386          * @return int
 387          */
 388         public function estimateRowCount( $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = array() ) {
 389                 $options['EXPLAIN'] = true;
 390                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 391                 if ( $res === false ) {
 392                         return false;
 393                 }
 394                 if ( !$this->numRows( $res ) ) {
 395                         return 0;
 396                 }
 397
 398                 $rows = 1;
 399                 foreach ( $res as $plan ) {
 400                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 401                 }
 402
 403                 return $rows;
 404         }
 405
 406         /**
 407          * @param $table string
 408          * @param $field string
 409          * @return bool|MySQLField
 410          */
 411         function fieldInfo( $table, $field ) {
 412                 $table = $this->tableName( $table );
 413                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 414                 if ( !$res ) {
 415                         return false;
 416                 }
 417                 $n = $this->mysqlNumFields( $res->result );
 418                 for ( $i = 0; $i < $n; $i++ ) {
 419                         $meta = $this->mysqlFetchField( $res->result, $i );
 420                         if ( $field == $meta->name ) {
 421                                 return new MySQLField( $meta );
 422                         }
 423                 }
 424
 425                 return false;
 426         }
 427
 428         /**
 429          * Get column information from a result
 430          *
 431          * @param $res Raw result
 432          * @param $n int
 433          * @return stdClass
 434          */
 435         abstract protected function mysqlFetchField( $res, $n );
 436
 437         /**
 438          * Get information about an index into an object
 439          * Returns false if the index does not exist
 440          *
 441          * @param $table string
 442          * @param $index string
 443          * @param $fname string
 444          * @return bool|array|null False or null on failure
 445          */
 446         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 447                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 448                 # SHOW INDEX should work for 3.x and up:
 449                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 450                 $table = $this->tableName( $table );
 451                 $index = $this->indexName( $index );
 452
 453                 $sql = 'SHOW INDEX FROM ' . $table;
 454                 $res = $this->query( $sql, $fname );
 455
 456                 if ( !$res ) {
 457                         return null;
 458                 }
 459
 460                 $result = array();
 461
 462                 foreach ( $res as $row ) {
 463                         if ( $row->Key_name == $index ) {
 464                                 $result[] = $row;
 465                         }
 466                 }
 467
 468                 return empty( $result ) ? false : $result;
 469         }
 470
 471         /**
 472          * @param $s string
 473          *
 474          * @return string
 475          */
 476         function strencode( $s ) {
 477                 $sQuoted = $this->mysqlRealEscapeString( $s );
 478
 479                 if ( $sQuoted === false ) {
 480                         $this->ping();
 481                         $sQuoted = $this->mysqlRealEscapeString( $s );
 482                 }
 483
 484                 return $sQuoted;
 485         }
 486
 487         /**
 488          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 489          *
 490          * @param $s string
 491          *
 492          * @return string
 493          */
 494         public function addIdentifierQuotes( $s ) {
 495                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 496                 // Remove NUL bytes and escape backticks by doubling
 497                 return '`' . str_replace( array( "\0", '`' ), array( '', '``' ), $s ) . '`';
 498         }
 499
 500         /**
 501          * @param $name string
 502          * @return bool
 503          */
 504         public function isQuotedIdentifier( $name ) {
 505                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 506         }
 507
 508         /**
 509          * @return bool
 510          */
 511         function ping() {
 512                 $ping = $this->mysqlPing();
 513                 if ( $ping ) {
 514                         return true;
 515                 }
 516
 517                 $this->closeConnection();
 518                 $this->mOpened = false;
 519                 $this->mConn = false;
 520                 $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
 521
 522                 return true;
 523         }
 524
 525         /**
 526          * Ping a server connection or reconnect if there is no connection
 527          *
 528          * @return bool
 529          */
 530         abstract protected function mysqlPing();
 531
 532         /**
 533          * Returns slave lag.
 534          *
 535          * This will do a SHOW SLAVE STATUS
 536          *
 537          * @return int
 538          */
 539         function getLag() {
 540                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 541                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
 542
 543                         return $this->mFakeSlaveLag;
 544                 }
 545
 546                 return $this->getLagFromSlaveStatus();
 547         }
 548
 549         /**
 550          * @return bool|int
 551          */
 552         function getLagFromSlaveStatus() {
 553                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 554                 if ( !$res ) {
 555                         return false;
 556                 }
 557                 $row = $res->fetchObject();
 558                 if ( !$row ) {
 559                         return false;
 560                 }
 561                 if ( strval( $row->Seconds_Behind_Master ) === '' ) {
 562                         return false;
 563                 } else {
 564                         return intval( $row->Seconds_Behind_Master );
 565                 }
 566         }
 567
 568         /**
 569          * @deprecated in 1.19, use getLagFromSlaveStatus
 570          *
 571          * @return bool|int
 572          */
 573         function getLagFromProcesslist() {
 574                 wfDeprecated( __METHOD__, '1.19' );
 575                 $res = $this->query( 'SHOW PROCESSLIST', __METHOD__ );
 576                 if ( !$res ) {
 577                         return false;
 578                 }
 579                 # Find slave SQL thread
 580                 foreach ( $res as $row ) {
 581                         /* This should work for most situations - when default db
 582                          * for thread is not specified, it had no events executed,
 583                          * and therefore it doesn't know yet how lagged it is.
 584                          *
 585                          * Relay log I/O thread does not select databases.
 586                          */
 587                         if ( $row->User == 'system user' &&
 588                                 $row->State != 'Waiting for master to send event' &&
 589                                 $row->State != 'Connecting to master' &&
 590                                 $row->State != 'Queueing master event to the relay log' &&
 591                                 $row->State != 'Waiting for master update' &&
 592                                 $row->State != 'Requesting binlog dump' &&
 593                                 $row->State != 'Waiting to reconnect after a failed master event read' &&
 594                                 $row->State != 'Reconnecting after a failed master event read' &&
 595                                 $row->State != 'Registering slave on master'
 596                         ) {
 597                                 # This is it, return the time (except -ve)
 598                                 if ( $row->Time > 0x7fffffff ) {
 599                                         return false;
 600                                 } else {
 601                                         return $row->Time;
 602                                 }
 603                         }
 604                 }
 605
 606                 return false;
 607         }
 608
 609         /**
 610          * Wait for the slave to catch up to a given master position.
 611          * @TODO: return values for this and base class are rubbish
 612          *
 613          * @param $pos DBMasterPos object
 614          * @param $timeout Integer: the maximum number of seconds to wait for synchronisation
 615          * @return bool|string
 616          */
 617         function masterPosWait( DBMasterPos $pos, $timeout ) {
 618                 if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
 619                         return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 620                 }
 621
 622                 wfProfileIn( __METHOD__ );
 623                 # Commit any open transactions
 624                 $this->commit( __METHOD__, 'flush' );
 625
 626                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 627                         $status = parent::masterPosWait( $pos, $timeout );
 628                         wfProfileOut( __METHOD__ );
 629
 630                         return $status;
 631                 }
 632
 633                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 634                 $encFile = $this->addQuotes( $pos->file );
 635                 $encPos = intval( $pos->pos );
 636                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 637                 $res = $this->doQuery( $sql );
 638
 639                 $status = false;
 640                 if ( $res && $row = $this->fetchRow( $res ) ) {
 641                         $status = $row[0]; // can be NULL, -1, or 0+ per the MySQL manual
 642                         if ( ctype_digit( $status ) ) { // success
 643                                 $this->lastKnownSlavePos = $pos;
 644                         }
 645                 }
 646
 647                 wfProfileOut( __METHOD__ );
 648
 649                 return $status;
 650         }
 651
 652         /**
 653          * Get the position of the master from SHOW SLAVE STATUS
 654          *
 655          * @return MySQLMasterPos|bool
 656          */
 657         function getSlavePos() {
 658                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 659                         return parent::getSlavePos();
 660                 }
 661
 662                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
 663                 $row = $this->fetchObject( $res );
 664
 665                 if ( $row ) {
 666                         $pos = isset( $row->Exec_master_log_pos ) ? $row->Exec_master_log_pos : $row->Exec_Master_Log_Pos;
 667
 668                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
 669                 } else {
 670                         return false;
 671                 }
 672         }
 673
 674         /**
 675          * Get the position of the master from SHOW MASTER STATUS
 676          *
 677          * @return MySQLMasterPos|bool
 678          */
 679         function getMasterPos() {
 680                 if ( $this->mFakeMaster ) {
 681                         return parent::getMasterPos();
 682                 }
 683
 684                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
 685                 $row = $this->fetchObject( $res );
 686
 687                 if ( $row ) {
 688                         return new MySQLMasterPos( $row->File, $row->Position );
 689                 } else {
 690                         return false;
 691                 }
 692         }
 693
 694         /**
 695          * @param $index
 696          * @return string
 697          */
 698         function useIndexClause( $index ) {
 699                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 700         }
 701
 702         /**
 703          * @return string
 704          */
 705         function lowPriorityOption() {
 706                 return 'LOW_PRIORITY';
 707         }
 708
 709         /**
 710          * @return string
 711          */
 712         public function getSoftwareLink() {
 713                 return '[http://www.mysql.com/ MySQL]';
 714         }
 715
 716         /**
 717          * @param $options array
 718          */
 719         public function setSessionOptions( array $options ) {
 720                 if ( isset( $options['connTimeout'] ) ) {
 721                         $timeout = (int)$options['connTimeout'];
 722                         $this->query( "SET net_read_timeout=$timeout" );
 723                         $this->query( "SET net_write_timeout=$timeout" );
 724                 }
 725         }
 726
 727         public function streamStatementEnd( &$sql, &$newLine ) {
 728                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 729                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 730                         $this->delimiter = $m[1];
 731                         $newLine = '';
 732                 }
 733
 734                 return parent::streamStatementEnd( $sql, $newLine );
 735         }
 736
 737         /**
 738          * Check to see if a named lock is available. This is non-blocking.
 739          *
 740          * @param string $lockName name of lock to poll
 741          * @param string $method name of method calling us
 742          * @return Boolean
 743          * @since 1.20
 744          */
 745         public function lockIsFree( $lockName, $method ) {
 746                 $lockName = $this->addQuotes( $lockName );
 747                 $result = $this->query( "SELECT IS_FREE_LOCK($lockName) AS lockstatus", $method );
 748                 $row = $this->fetchObject( $result );
 749
 750                 return ( $row->lockstatus == 1 );
 751         }
 752
 753         /**
 754          * @param $lockName string
 755          * @param $method string
 756          * @param $timeout int
 757          * @return bool
 758          */
 759         public function lock( $lockName, $method, $timeout = 5 ) {
 760                 $lockName = $this->addQuotes( $lockName );
 761                 $result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
 762                 $row = $this->fetchObject( $result );
 763
 764                 if ( $row->lockstatus == 1 ) {
 765                         return true;
 766                 } else {
 767                         wfDebug( __METHOD__ . " failed to acquire lock\n" );
 768
 769                         return false;
 770                 }
 771         }
 772
 773         /**
 774          * FROM MYSQL DOCS: http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
 775          * @param $lockName string
 776          * @param $method string
 777          * @return bool
 778          */
 779         public function unlock( $lockName, $method ) {
 780                 $lockName = $this->addQuotes( $lockName );
 781                 $result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
 782                 $row = $this->fetchObject( $result );
 783
 784                 return ( $row->lockstatus == 1 );
 785         }
 786
 787         /**
 788          * @param $read array
 789          * @param $write array
 790          * @param $method string
 791          * @param $lowPriority bool
 792          * @return bool
 793          */
 794         public function lockTables( $read, $write, $method, $lowPriority = true ) {
 795                 $items = array();
 796
 797                 foreach ( $write as $table ) {
 798                         $tbl = $this->tableName( $table ) .
 799                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
 800                                 ' WRITE';
 801                         $items[] = $tbl;
 802                 }
 803                 foreach ( $read as $table ) {
 804                         $items[] = $this->tableName( $table ) . ' READ';
 805                 }
 806                 $sql = "LOCK TABLES " . implode( ',', $items );
 807                 $this->query( $sql, $method );
 808
 809                 return true;
 810         }
 811
 812         /**
 813          * @param $method string
 814          * @return bool
 815          */
 816         public function unlockTables( $method ) {
 817                 $this->query( "UNLOCK TABLES", $method );
 818
 819                 return true;
 820         }
 821
 822         /**
 823          * Get search engine class. All subclasses of this
 824          * need to implement this if they wish to use searching.
 825          *
 826          * @return String
 827          */
 828         public function getSearchEngine() {
 829                 return 'SearchMySQL';
 830         }
 831
 832         /**
 833          * @param bool $value
 834          * @return mixed
 835          */
 836         public function setBigSelects( $value = true ) {
 837                 if ( $value === 'default' ) {
 838                         if ( $this->mDefaultBigSelects === null ) {
 839                                 # Function hasn't been called before so it must already be set to the default
 840                                 return;
 841                         } else {
 842                                 $value = $this->mDefaultBigSelects;
 843                         }
 844                 } elseif ( $this->mDefaultBigSelects === null ) {
 845                         $this->mDefaultBigSelects = (bool)$this->selectField( false, '@@sql_big_selects' );
 846                 }
 847                 $encValue = $value ? '1' : '0';
 848                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
 849         }
 850
 851         /**
 852          * DELETE where the condition is a join. MySql uses multi-table deletes.
 853          * @param $delTable string
 854          * @param $joinTable string
 855          * @param $delVar string
 856          * @param $joinVar string
 857          * @param $conds array|string
 858          * @param bool|string $fname bool
 859          * @throws DBUnexpectedError
 860          * @return bool|ResultWrapper
 861          */
 862         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) {
 863                 if ( !$conds ) {
 864                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
 865                 }
 866
 867                 $delTable = $this->tableName( $delTable );
 868                 $joinTable = $this->tableName( $joinTable );
 869                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
 870
 871                 if ( $conds != '*' ) {
 872                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
 873                 }
 874
 875                 return $this->query( $sql, $fname );
 876         }
 877
 878         /**
 879          * @param string $table
 880          * @param array $rows
 881          * @param array $uniqueIndexes
 882          * @param array $set
 883          * @param string $fname
 884          * @param array $options
 885          * @return bool
 886          */
 887         public function upsert(
 888                 $table, array $rows, array $uniqueIndexes, array $set, $fname = __METHOD__
 889         ) {
 890                 if ( !count( $rows ) ) {
 891                         return true; // nothing to do
 892                 }
 893                 $rows = is_array( reset( $rows ) ) ? $rows : array( $rows );
 894
 895                 $table = $this->tableName( $table );
 896                 $columns = array_keys( $rows[0] );
 897
 898                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
 899                 $rowTuples = array();
 900                 foreach ( $rows as $row ) {
 901                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
 902                 }
 903                 $sql .= implode( ',', $rowTuples );
 904                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, LIST_SET );
 905
 906                 return (bool)$this->query( $sql, $fname );
 907         }
 908
 909         /**
 910          * Determines how long the server has been up
 911          *
 912          * @return int
 913          */
 914         function getServerUptime() {
 915                 $vars = $this->getMysqlStatus( 'Uptime' );
 916
 917                 return (int)$vars['Uptime'];
 918         }
 919
 920         /**
 921          * Determines if the last failure was due to a deadlock
 922          *
 923          * @return bool
 924          */
 925         function wasDeadlock() {
 926                 return $this->lastErrno() == 1213;
 927         }
 928
 929         /**
 930          * Determines if the last failure was due to a lock timeout
 931          *
 932          * @return bool
 933          */
 934         function wasLockTimeout() {
 935                 return $this->lastErrno() == 1205;
 936         }
 937
 938         /**
 939          * Determines if the last query error was something that should be dealt
 940          * with by pinging the connection and reissuing the query
 941          *
 942          * @return bool
 943          */
 944         function wasErrorReissuable() {
 945                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
 946         }
 947
 948         /**
 949          * Determines if the last failure was due to the database being read-only.
 950          *
 951          * @return bool
 952          */
 953         function wasReadOnlyError() {
 954                 return $this->lastErrno() == 1223 ||
 955                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
 956         }
 957
 958         /**
 959          * @param $oldName
 960          * @param $newName
 961          * @param $temporary bool
 962          * @param $fname string
 963          */
 964         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 965                 $tmp = $temporary ? 'TEMPORARY ' : '';
 966                 $newName = $this->addIdentifierQuotes( $newName );
 967                 $oldName = $this->addIdentifierQuotes( $oldName );
 968                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
 969                 $this->query( $query, $fname );
 970         }
 971
 972         /**
 973          * List all tables on the database
 974          *
 975          * @param string $prefix Only show tables with this prefix, e.g. mw_
 976          * @param string $fname calling function name
 977          * @return array
 978          */
 979         function listTables( $prefix = null, $fname = __METHOD__ ) {
 980                 $result = $this->query( "SHOW TABLES", $fname );
 981
 982                 $endArray = array();
 983
 984                 foreach ( $result as $table ) {
 985                         $vars = get_object_vars( $table );
 986                         $table = array_pop( $vars );
 987
 988                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
 989                                 $endArray[] = $table;
 990                         }
 991                 }
 992
 993                 return $endArray;
 994         }
 995
 996         /**
 997          * @param $tableName
 998          * @param $fName string
 999          * @return bool|ResultWrapper
1000          */
1001         public function dropTable( $tableName, $fName = __METHOD__ ) {
1002                 if ( !$this->tableExists( $tableName, $fName ) ) {
1003                         return false;
1004                 }
1005
1006                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1007         }
1008
1009         /**
1010          * @return array
1011          */
1012         protected function getDefaultSchemaVars() {
1013                 $vars = parent::getDefaultSchemaVars();
1014                 $vars['wgDBTableOptions'] = str_replace( 'TYPE', 'ENGINE', $GLOBALS['wgDBTableOptions'] );
1015                 $vars['wgDBTableOptions'] = str_replace( 'CHARSET=mysql4', 'CHARSET=binary', $vars['wgDBTableOptions'] );
1016
1017                 return $vars;
1018         }
1019
1020         /**
1021          * Get status information from SHOW STATUS in an associative array
1022          *
1023          * @param $which string
1024          * @return array
1025          */
1026         function getMysqlStatus( $which = "%" ) {
1027                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1028                 $status = array();
1029
1030                 foreach ( $res as $row ) {
1031                         $status[$row->Variable_name] = $row->Value;
1032                 }
1033
1034                 return $status;
1035         }
1036
1037         /**
1038          * Lists VIEWs in the database
1039          *
1040          * @param string $prefix Only show VIEWs with this prefix, eg.
1041          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1042          * @param string $fname Name of calling function
1043          * @return array
1044          * @since 1.22
1045          */
1046         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1047
1048                 if ( !isset( $this->allViews ) ) {
1049
1050                         // The name of the column containing the name of the VIEW
1051                         $propertyName = 'Tables_in_' . $this->mDBname;
1052
1053                         // Query for the VIEWS
1054                         $result = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1055                         $this->allViews = array();
1056                         while ( ( $row = $this->fetchRow( $result ) ) !== false ) {
1057                                 array_push( $this->allViews, $row[$propertyName] );
1058                         }
1059                 }
1060
1061                 if ( is_null( $prefix ) || $prefix === '' ) {
1062                         return $this->allViews;
1063                 }
1064
1065                 $filteredViews = array();
1066                 foreach ( $this->allViews as $viewName ) {
1067                         // Does the name of this VIEW start with the table-prefix?
1068                         if ( strpos( $viewName, $prefix ) === 0 ) {
1069                                 array_push( $filteredViews, $viewName );
1070                         }
1071                 }
1072
1073                 return $filteredViews;
1074         }
1075
1076         /**
1077          * Differentiates between a TABLE and a VIEW.
1078          *
1079          * @param $name string: Name of the TABLE/VIEW to test
1080          * @return bool
1081          * @since 1.22
1082          */
1083         public function isView( $name, $prefix = null ) {
1084                 return in_array( $name, $this->listViews( $prefix ) );
1085         }
1086 }
1087
1088 /**
1089  * Utility class.
1090  * @ingroup Database
1091  */
1092 class MySQLField implements Field {
1093         private $name, $tablename, $default, $max_length, $nullable,
1094                 $is_pk, $is_unique, $is_multiple, $is_key, $type, $binary;
1095
1096         function __construct( $info ) {
1097                 $this->name = $info->name;
1098                 $this->tablename = $info->table;
1099                 $this->default = $info->def;
1100                 $this->max_length = $info->max_length;
1101                 $this->nullable = !$info->not_null;
1102                 $this->is_pk = $info->primary_key;
1103                 $this->is_unique = $info->unique_key;
1104                 $this->is_multiple = $info->multiple_key;
1105                 $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
1106                 $this->type = $info->type;
1107                 $this->binary = isset( $info->binary ) ? $info->binary : false;
1108         }
1109
1110         /**
1111          * @return string
1112          */
1113         function name() {
1114                 return $this->name;
1115         }
1116
1117         /**
1118          * @return string
1119          */
1120         function tableName() {
1121                 return $this->tableName;
1122         }
1123
1124         /**
1125          * @return string
1126          */
1127         function type() {
1128                 return $this->type;
1129         }
1130
1131         /**
1132          * @return bool
1133          */
1134         function isNullable() {
1135                 return $this->nullable;
1136         }
1137
1138         function defaultValue() {
1139                 return $this->default;
1140         }
1141
1142         /**
1143          * @return bool
1144          */
1145         function isKey() {
1146                 return $this->is_key;
1147         }
1148
1149         /**
1150          * @return bool
1151          */
1152         function isMultipleKey() {
1153                 return $this->is_multiple;
1154         }
1155
1156         function isBinary() {
1157                 return $this->binary;
1158         }
1159 }
1160
1161 class MySQLMasterPos implements DBMasterPos {
1162         var $file, $pos;
1163
1164         function __construct( $file, $pos ) {
1165                 $this->file = $file;
1166                 $this->pos = $pos;
1167         }
1168
1169         function __toString() {
1170                 // e.g db1034-bin.000976/843431247
1171                 return "{$this->file}/{$this->pos}";
1172         }
1173
1174         /**
1175          * @return array|false (int, int)
1176          */
1177         protected function getCoordinates() {
1178                 $m = array();
1179                 if ( preg_match( '!\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
1180                         return array( (int)$m[1], (int)$m[2] );
1181                 }
1182
1183                 return false;
1184         }
1185
1186         function hasReached( MySQLMasterPos $pos ) {
1187                 $thisPos = $this->getCoordinates();
1188                 $thatPos = $pos->getCoordinates();
1189
1190                 return ( $thisPos && $thatPos && $thisPos >= $thatPos );
1191         }
1192 }