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