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