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         /** @var null|int */
  37         protected $mFakeSlaveLag = null;
  38
  39         protected $mFakeMaster = false;
  40
  41         /** @var string|null */
  42         private $serverVersion = null;
  43
  44         /**
  45          * @return string
  46          */
  47         function getType() {
  48                 return 'mysql';
  49         }
  50
  51         /**
  52          * @param string $server
  53          * @param string $user
  54          * @param string $password
  55          * @param string $dbName
  56          * @throws Exception|DBConnectionError
  57          * @return bool
  58          */
  59         function open( $server, $user, $password, $dbName ) {
  60                 global $wgAllDBsAreLocalhost, $wgSQLMode;
  61                 wfProfileIn( __METHOD__ );
  62
  63                 # Debugging hack -- fake cluster
  64                 if ( $wgAllDBsAreLocalhost ) {
  65                         $realServer = 'localhost';
  66                 } else {
  67                         $realServer = $server;
  68                 }
  69                 $this->close();
  70                 $this->mServer = $server;
  71                 $this->mUser = $user;
  72                 $this->mPassword = $password;
  73                 $this->mDBname = $dbName;
  74
  75                 wfProfileIn( "dbconnect-$server" );
  76
  77                 # The kernel's default SYN retransmission period is far too slow for us,
  78                 # so we use a short timeout plus a manual retry. Retrying means that a small
  79                 # but finite rate of SYN packet loss won't cause user-visible errors.
  80                 $this->mConn = false;
  81                 $this->installErrorHandler();
  82                 try {
  83                         $this->mConn = $this->mysqlConnect( $realServer );
  84                 } catch ( Exception $ex ) {
  85                         wfProfileOut( "dbconnect-$server" );
  86                         wfProfileOut( __METHOD__ );
  87                         $this->restoreErrorHandler();
  88                         throw $ex;
  89                 }
  90                 $error = $this->restoreErrorHandler();
  91
  92                 wfProfileOut( "dbconnect-$server" );
  93
  94                 # Always log connection errors
  95                 if ( !$this->mConn ) {
  96                         if ( !$error ) {
  97                                 $error = $this->lastError();
  98                         }
  99                         wfLogDBError( "Error connecting to {$this->mServer}: $error" );
 100                         wfDebug( "DB connection error\n" .
 101                                 "Server: $server, User: $user, Password: " .
 102                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 103
 104                         wfProfileOut( __METHOD__ );
 105
 106                         $this->reportConnectionError( $error );
 107                 }
 108
 109                 if ( $dbName != '' ) {
 110                         wfSuppressWarnings();
 111                         $success = $this->selectDB( $dbName );
 112                         wfRestoreWarnings();
 113                         if ( !$success ) {
 114                                 wfLogDBError( "Error selecting database $dbName on server {$this->mServer}" );
 115                                 wfDebug( "Error selecting database $dbName on server {$this->mServer} " .
 116                                         "from client host " . wfHostname() . "\n" );
 117
 118                                 wfProfileOut( __METHOD__ );
 119
 120                                 $this->reportConnectionError( "Error selecting database $dbName" );
 121                         }
 122                 }
 123
 124                 // Tell the server what we're communicating with
 125                 if ( !$this->connectInitCharset() ) {
 126                         $this->reportConnectionError( "Error setting character set" );
 127                 }
 128
 129                 // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 130                 if ( is_string( $wgSQLMode ) ) {
 131                         $mode = $this->addQuotes( $wgSQLMode );
 132                         // Use doQuery() to avoid opening implicit transactions (DBO_TRX)
 133                         $success = $this->doQuery( "SET sql_mode = $mode", __METHOD__ );
 134                         if ( !$success ) {
 135                                 wfLogDBError( "Error setting sql_mode to $mode on server {$this->mServer}" );
 136                                 wfProfileOut( __METHOD__ );
 137                                 $this->reportConnectionError( "Error setting sql_mode to $mode" );
 138                         }
 139                 }
 140
 141                 $this->mOpened = true;
 142                 wfProfileOut( __METHOD__ );
 143
 144                 return true;
 145         }
 146
 147         /**
 148          * Set the character set information right after connection
 149          * @return bool
 150          */
 151         protected function connectInitCharset() {
 152                 global $wgDBmysql5;
 153
 154                 if ( $wgDBmysql5 ) {
 155                         // Tell the server we're communicating with it in UTF-8.
 156                         // This may engage various charset conversions.
 157                         return $this->mysqlSetCharset( 'utf8' );
 158                 } else {
 159                         return $this->mysqlSetCharset( 'binary' );
 160                 }
 161         }
 162
 163         /**
 164          * Open a connection to a MySQL server
 165          *
 166          * @param string $realServer
 167          * @return mixed Raw connection
 168          * @throws DBConnectionError
 169          */
 170         abstract protected function mysqlConnect( $realServer );
 171
 172         /**
 173          * Set the character set of the MySQL link
 174          *
 175          * @param string $charset
 176          * @return bool
 177          */
 178         abstract protected function mysqlSetCharset( $charset );
 179
 180         /**
 181          * @param ResultWrapper|resource $res
 182          * @throws DBUnexpectedError
 183          */
 184         function freeResult( $res ) {
 185                 if ( $res instanceof ResultWrapper ) {
 186                         $res = $res->result;
 187                 }
 188                 wfSuppressWarnings();
 189                 $ok = $this->mysqlFreeResult( $res );
 190                 wfRestoreWarnings();
 191                 if ( !$ok ) {
 192                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 193                 }
 194         }
 195
 196         /**
 197          * Free result memory
 198          *
 199          * @param resource $res Raw result
 200          * @return bool
 201          */
 202         abstract protected function mysqlFreeResult( $res );
 203
 204         /**
 205          * @param ResultWrapper|resource $res
 206          * @return stdClass|bool
 207          * @throws DBUnexpectedError
 208          */
 209         function fetchObject( $res ) {
 210                 if ( $res instanceof ResultWrapper ) {
 211                         $res = $res->result;
 212                 }
 213                 wfSuppressWarnings();
 214                 $row = $this->mysqlFetchObject( $res );
 215                 wfRestoreWarnings();
 216
 217                 $errno = $this->lastErrno();
 218                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 219                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 220                 // these are the only errors mysql_fetch_object can cause.
 221                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 222                 if ( $errno == 2000 || $errno == 2013 ) {
 223                         throw new DBUnexpectedError(
 224                                 $this,
 225                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 226                         );
 227                 }
 228
 229                 return $row;
 230         }
 231
 232         /**
 233          * Fetch a result row as an object
 234          *
 235          * @param resource $res Raw result
 236          * @return stdClass
 237          */
 238         abstract protected function mysqlFetchObject( $res );
 239
 240         /**
 241          * @param ResultWrapper|resource $res
 242          * @return array|bool
 243          * @throws DBUnexpectedError
 244          */
 245         function fetchRow( $res ) {
 246                 if ( $res instanceof ResultWrapper ) {
 247                         $res = $res->result;
 248                 }
 249                 wfSuppressWarnings();
 250                 $row = $this->mysqlFetchArray( $res );
 251                 wfRestoreWarnings();
 252
 253                 $errno = $this->lastErrno();
 254                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 255                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 256                 // these are the only errors mysql_fetch_array can cause.
 257                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 258                 if ( $errno == 2000 || $errno == 2013 ) {
 259                         throw new DBUnexpectedError(
 260                                 $this,
 261                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 262                         );
 263                 }
 264
 265                 return $row;
 266         }
 267
 268         /**
 269          * Fetch a result row as an associative and numeric array
 270          *
 271          * @param resource $res Raw result
 272          * @return array
 273          */
 274         abstract protected function mysqlFetchArray( $res );
 275
 276         /**
 277          * @throws DBUnexpectedError
 278          * @param ResultWrapper|resource $res
 279          * @return int
 280          */
 281         function numRows( $res ) {
 282                 if ( $res instanceof ResultWrapper ) {
 283                         $res = $res->result;
 284                 }
 285                 wfSuppressWarnings();
 286                 $n = $this->mysqlNumRows( $res );
 287                 wfRestoreWarnings();
 288
 289                 // Unfortunately, mysql_num_rows does not reset the last errno.
 290                 // We are not checking for any errors here, since
 291                 // these are no errors mysql_num_rows can cause.
 292                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 293                 // See https://bugzilla.wikimedia.org/42430
 294                 return $n;
 295         }
 296
 297         /**
 298          * Get number of rows in result
 299          *
 300          * @param resource $res Raw result
 301          * @return int
 302          */
 303         abstract protected function mysqlNumRows( $res );
 304
 305         /**
 306          * @param ResultWrapper|resource $res
 307          * @return int
 308          */
 309         function numFields( $res ) {
 310                 if ( $res instanceof ResultWrapper ) {
 311                         $res = $res->result;
 312                 }
 313
 314                 return $this->mysqlNumFields( $res );
 315         }
 316
 317         /**
 318          * Get number of fields in result
 319          *
 320          * @param resource $res Raw result
 321          * @return int
 322          */
 323         abstract protected function mysqlNumFields( $res );
 324
 325         /**
 326          * @param ResultWrapper|resource $res
 327          * @param int $n
 328          * @return string
 329          */
 330         function fieldName( $res, $n ) {
 331                 if ( $res instanceof ResultWrapper ) {
 332                         $res = $res->result;
 333                 }
 334
 335                 return $this->mysqlFieldName( $res, $n );
 336         }
 337
 338         /**
 339          * Get the name of the specified field in a result
 340          *
 341          * @param ResultWrapper|resource $res
 342          * @param int $n
 343          * @return string
 344          */
 345         abstract protected function mysqlFieldName( $res, $n );
 346
 347         /**
 348          * mysql_field_type() wrapper
 349          * @param ResultWrapper|resource $res
 350          * @param int $n
 351          * @return string
 352          */
 353         public function fieldType( $res, $n ) {
 354                 if ( $res instanceof ResultWrapper ) {
 355                         $res = $res->result;
 356                 }
 357
 358                 return $this->mysqlFieldType( $res, $n );
 359         }
 360
 361         /**
 362          * Get the type of the specified field in a result
 363          *
 364          * @param ResultWrapper|resource $res
 365          * @param int $n
 366          * @return string
 367          */
 368         abstract protected function mysqlFieldType( $res, $n );
 369
 370         /**
 371          * @param ResultWrapper|resource $res
 372          * @param int $row
 373          * @return bool
 374          */
 375         function dataSeek( $res, $row ) {
 376                 if ( $res instanceof ResultWrapper ) {
 377                         $res = $res->result;
 378                 }
 379
 380                 return $this->mysqlDataSeek( $res, $row );
 381         }
 382
 383         /**
 384          * Move internal result pointer
 385          *
 386          * @param ResultWrapper|resource $res
 387          * @param int $row
 388          * @return bool
 389          */
 390         abstract protected function mysqlDataSeek( $res, $row );
 391
 392         /**
 393          * @return string
 394          */
 395         function lastError() {
 396                 if ( $this->mConn ) {
 397                         # Even if it's non-zero, it can still be invalid
 398                         wfSuppressWarnings();
 399                         $error = $this->mysqlError( $this->mConn );
 400                         if ( !$error ) {
 401                                 $error = $this->mysqlError();
 402                         }
 403                         wfRestoreWarnings();
 404                 } else {
 405                         $error = $this->mysqlError();
 406                 }
 407                 if ( $error ) {
 408                         $error .= ' (' . $this->mServer . ')';
 409                 }
 410
 411                 return $error;
 412         }
 413
 414         /**
 415          * Returns the text of the error message from previous MySQL operation
 416          *
 417          * @param resource $conn Raw connection
 418          * @return string
 419          */
 420         abstract protected function mysqlError( $conn = null );
 421
 422         /**
 423          * @param string $table
 424          * @param array $uniqueIndexes
 425          * @param array $rows
 426          * @param string $fname
 427          * @return ResultWrapper
 428          */
 429         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 430                 return $this->nativeReplace( $table, $rows, $fname );
 431         }
 432
 433         /**
 434          * Estimate rows in dataset
 435          * Returns estimated count, based on EXPLAIN output
 436          * Takes same arguments as Database::select()
 437          *
 438          * @param string|array $table
 439          * @param string|array $vars
 440          * @param string|array $conds
 441          * @param string $fname
 442          * @param string|array $options
 443          * @return bool|int
 444          */
 445         public function estimateRowCount( $table, $vars = '*', $conds = '',
 446                 $fname = __METHOD__, $options = array()
 447         ) {
 448                 $options['EXPLAIN'] = true;
 449                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 450                 if ( $res === false ) {
 451                         return false;
 452                 }
 453                 if ( !$this->numRows( $res ) ) {
 454                         return 0;
 455                 }
 456
 457                 $rows = 1;
 458                 foreach ( $res as $plan ) {
 459                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 460                 }
 461
 462                 return $rows;
 463         }
 464
 465         /**
 466          * @param string $table
 467          * @param string $field
 468          * @return bool|MySQLField
 469          */
 470         function fieldInfo( $table, $field ) {
 471                 $table = $this->tableName( $table );
 472                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 473                 if ( !$res ) {
 474                         return false;
 475                 }
 476                 $n = $this->mysqlNumFields( $res->result );
 477                 for ( $i = 0; $i < $n; $i++ ) {
 478                         $meta = $this->mysqlFetchField( $res->result, $i );
 479                         if ( $field == $meta->name ) {
 480                                 return new MySQLField( $meta );
 481                         }
 482                 }
 483
 484                 return false;
 485         }
 486
 487         /**
 488          * Get column information from a result
 489          *
 490          * @param resource $res Raw result
 491          * @param int $n
 492          * @return stdClass
 493          */
 494         abstract protected function mysqlFetchField( $res, $n );
 495
 496         /**
 497          * Get information about an index into an object
 498          * Returns false if the index does not exist
 499          *
 500          * @param string $table
 501          * @param string $index
 502          * @param string $fname
 503          * @return bool|array|null False or null on failure
 504          */
 505         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 506                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 507                 # SHOW INDEX should work for 3.x and up:
 508                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 509                 $table = $this->tableName( $table );
 510                 $index = $this->indexName( $index );
 511
 512                 $sql = 'SHOW INDEX FROM ' . $table;
 513                 $res = $this->query( $sql, $fname );
 514
 515                 if ( !$res ) {
 516                         return null;
 517                 }
 518
 519                 $result = array();
 520
 521                 foreach ( $res as $row ) {
 522                         if ( $row->Key_name == $index ) {
 523                                 $result[] = $row;
 524                         }
 525                 }
 526
 527                 return empty( $result ) ? false : $result;
 528         }
 529
 530         /**
 531          * @param string $s
 532          * @return string
 533          */
 534         function strencode( $s ) {
 535                 $sQuoted = $this->mysqlRealEscapeString( $s );
 536
 537                 if ( $sQuoted === false ) {
 538                         $this->ping();
 539                         $sQuoted = $this->mysqlRealEscapeString( $s );
 540                 }
 541
 542                 return $sQuoted;
 543         }
 544
 545         /**
 546          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 547          *
 548          * @param string $s
 549          * @return string
 550          */
 551         public function addIdentifierQuotes( $s ) {
 552                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 553                 // Remove NUL bytes and escape backticks by doubling
 554                 return '`' . str_replace( array( "\0", '`' ), array( '', '``' ), $s ) . '`';
 555         }
 556
 557         /**
 558          * @param string $name
 559          * @return bool
 560          */
 561         public function isQuotedIdentifier( $name ) {
 562                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 563         }
 564
 565         /**
 566          * @return bool
 567          */
 568         function ping() {
 569                 $ping = $this->mysqlPing();
 570                 if ( $ping ) {
 571                         return true;
 572                 }
 573
 574                 $this->closeConnection();
 575                 $this->mOpened = false;
 576                 $this->mConn = false;
 577                 $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
 578
 579                 return true;
 580         }
 581
 582         /**
 583          * Ping a server connection or reconnect if there is no connection
 584          *
 585          * @return bool
 586          */
 587         abstract protected function mysqlPing();
 588
 589         /**
 590          * Set lag time in seconds for a fake slave
 591          *
 592          * @param int $lag
 593          */
 594         public function setFakeSlaveLag( $lag ) {
 595                 $this->mFakeSlaveLag = $lag;
 596         }
 597
 598         /**
 599          * Make this connection a fake master
 600          *
 601          * @param bool $enabled
 602          */
 603         public function setFakeMaster( $enabled = true ) {
 604                 $this->mFakeMaster = $enabled;
 605         }
 606
 607         /**
 608          * Returns slave lag.
 609          *
 610          * This will do a SHOW SLAVE STATUS
 611          *
 612          * @return int
 613          */
 614         function getLag() {
 615                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 616                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
 617
 618                         return $this->mFakeSlaveLag;
 619                 }
 620
 621                 return $this->getLagFromSlaveStatus();
 622         }
 623
 624         /**
 625          * @return bool|int
 626          */
 627         function getLagFromSlaveStatus() {
 628                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 629                 if ( !$res ) {
 630                         return false;
 631                 }
 632                 $row = $res->fetchObject();
 633                 if ( !$row ) {
 634                         return false;
 635                 }
 636                 if ( strval( $row->Seconds_Behind_Master ) === '' ) {
 637                         return false;
 638                 } else {
 639                         return intval( $row->Seconds_Behind_Master );
 640                 }
 641         }
 642
 643         /**
 644          * Wait for the slave to catch up to a given master position.
 645          * @todo Return values for this and base class are rubbish
 646          *
 647          * @param DBMasterPos|MySQLMasterPos $pos
 648          * @param int $timeout The maximum number of seconds to wait for synchronisation
 649          * @return int Zero if the slave was past that position already,
 650          *   greater than zero if we waited for some period of time, less than
 651          *   zero if we timed out.
 652          */
 653         function masterPosWait( DBMasterPos $pos, $timeout ) {
 654                 if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
 655                         return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 656                 }
 657
 658                 wfProfileIn( __METHOD__ );
 659                 # Commit any open transactions
 660                 $this->commit( __METHOD__, 'flush' );
 661
 662                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 663                         $wait = intval( ( $pos->pos - microtime( true ) + $this->mFakeSlaveLag ) * 1e6 );
 664
 665                         if ( $wait > $timeout * 1e6 ) {
 666                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
 667                                 wfProfileOut( __METHOD__ );
 668
 669                                 return -1;
 670                         } elseif ( $wait > 0 ) {
 671                                 wfDebug( "Fake slave waiting $wait us\n" );
 672                                 usleep( $wait );
 673                                 wfProfileOut( __METHOD__ );
 674
 675                                 return 1;
 676                         } else {
 677                                 wfDebug( "Fake slave up to date ($wait us)\n" );
 678                                 wfProfileOut( __METHOD__ );
 679
 680                                 return 0;
 681                         }
 682                 }
 683
 684                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 685                 $encFile = $this->addQuotes( $pos->file );
 686                 $encPos = intval( $pos->pos );
 687                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 688                 $res = $this->doQuery( $sql );
 689
 690                 $status = false;
 691                 if ( $res && $row = $this->fetchRow( $res ) ) {
 692                         $status = $row[0]; // can be NULL, -1, or 0+ per the MySQL manual
 693                         if ( ctype_digit( $status ) ) { // success
 694                                 $this->lastKnownSlavePos = $pos;
 695                         }
 696                 }
 697
 698                 wfProfileOut( __METHOD__ );
 699
 700                 return $status;
 701         }
 702
 703         /**
 704          * Get the position of the master from SHOW SLAVE STATUS
 705          *
 706          * @return MySQLMasterPos|bool
 707          */
 708         function getSlavePos() {
 709                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 710                         $pos = new MySQLMasterPos( 'fake', microtime( true ) - $this->mFakeSlaveLag );
 711                         wfDebug( __METHOD__ . ": fake slave pos = $pos\n" );
 712
 713                         return $pos;
 714                 }
 715
 716                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
 717                 $row = $this->fetchObject( $res );
 718
 719                 if ( $row ) {
 720                         $pos = isset( $row->Exec_master_log_pos )
 721                                 ? $row->Exec_master_log_pos
 722                                 : $row->Exec_Master_Log_Pos;
 723
 724                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
 725                 } else {
 726                         return false;
 727                 }
 728         }
 729
 730         /**
 731          * Get the position of the master from SHOW MASTER STATUS
 732          *
 733          * @return MySQLMasterPos|bool
 734          */
 735         function getMasterPos() {
 736                 if ( $this->mFakeMaster ) {
 737                         return new MySQLMasterPos( 'fake', microtime( true ) );
 738                 }
 739
 740                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
 741                 $row = $this->fetchObject( $res );
 742
 743                 if ( $row ) {
 744                         return new MySQLMasterPos( $row->File, $row->Position );
 745                 } else {
 746                         return false;
 747                 }
 748         }
 749
 750         /**
 751          * @param string $index
 752          * @return string
 753          */
 754         function useIndexClause( $index ) {
 755                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 756         }
 757
 758         /**
 759          * @return string
 760          */
 761         function lowPriorityOption() {
 762                 return 'LOW_PRIORITY';
 763         }
 764
 765         /**
 766          * @return string
 767          */
 768         public function getSoftwareLink() {
 769                 // MariaDB includes its name in its version string; this is how MariaDB's version of
 770                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
 771                 // in libmysql/libmysql.c).
 772                 $version = $this->getServerVersion();
 773                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 774                         return '[{{int:version-db-mariadb-url}} MariaDB]';
 775                 }
 776
 777                 // Percona Server's version suffix is not very distinctive, and @@version_comment
 778                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
 779                 // (Even Percona's version of mysql doesn't try to make the distinction.)
 780                 return '[{{int:version-db-mysql-url}} MySQL]';
 781         }
 782
 783         /**
 784          * @return string
 785          */
 786         public function getServerVersion() {
 787                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
 788                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
 789                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
 790                 if ( $this->serverVersion === null ) {
 791                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
 792                 }
 793                 return $this->serverVersion;
 794         }
 795
 796         /**
 797          * @param array $options
 798          */
 799         public function setSessionOptions( array $options ) {
 800                 if ( isset( $options['connTimeout'] ) ) {
 801                         $timeout = (int)$options['connTimeout'];
 802                         $this->query( "SET net_read_timeout=$timeout" );
 803                         $this->query( "SET net_write_timeout=$timeout" );
 804                 }
 805         }
 806
 807         /**
 808          * @param string $sql
 809          * @param string $newLine
 810          * @return bool
 811          */
 812         public function streamStatementEnd( &$sql, &$newLine ) {
 813                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 814                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 815                         $this->delimiter = $m[1];
 816                         $newLine = '';
 817                 }
 818
 819                 return parent::streamStatementEnd( $sql, $newLine );
 820         }
 821
 822         /**
 823          * Check to see if a named lock is available. This is non-blocking.
 824          *
 825          * @param string $lockName Name of lock to poll
 826          * @param string $method Name of method calling us
 827          * @return bool
 828          * @since 1.20
 829          */
 830         public function lockIsFree( $lockName, $method ) {
 831                 $lockName = $this->addQuotes( $lockName );
 832                 $result = $this->query( "SELECT IS_FREE_LOCK($lockName) AS lockstatus", $method );
 833                 $row = $this->fetchObject( $result );
 834
 835                 return ( $row->lockstatus == 1 );
 836         }
 837
 838         /**
 839          * @param string $lockName
 840          * @param string $method
 841          * @param int $timeout
 842          * @return bool
 843          */
 844         public function lock( $lockName, $method, $timeout = 5 ) {
 845                 $lockName = $this->addQuotes( $lockName );
 846                 $result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
 847                 $row = $this->fetchObject( $result );
 848
 849                 if ( $row->lockstatus == 1 ) {
 850                         return true;
 851                 } else {
 852                         wfDebug( __METHOD__ . " failed to acquire lock\n" );
 853
 854                         return false;
 855                 }
 856         }
 857
 858         /**
 859          * FROM MYSQL DOCS:
 860          * http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
 861          * @param string $lockName
 862          * @param string $method
 863          * @return bool
 864          */
 865         public function unlock( $lockName, $method ) {
 866                 $lockName = $this->addQuotes( $lockName );
 867                 $result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
 868                 $row = $this->fetchObject( $result );
 869
 870                 return ( $row->lockstatus == 1 );
 871         }
 872
 873         /**
 874          * @param array $read
 875          * @param array $write
 876          * @param string $method
 877          * @param bool $lowPriority
 878          * @return bool
 879          */
 880         public function lockTables( $read, $write, $method, $lowPriority = true ) {
 881                 $items = array();
 882
 883                 foreach ( $write as $table ) {
 884                         $tbl = $this->tableName( $table ) .
 885                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
 886                                 ' WRITE';
 887                         $items[] = $tbl;
 888                 }
 889                 foreach ( $read as $table ) {
 890                         $items[] = $this->tableName( $table ) . ' READ';
 891                 }
 892                 $sql = "LOCK TABLES " . implode( ',', $items );
 893                 $this->query( $sql, $method );
 894
 895                 return true;
 896         }
 897
 898         /**
 899          * @param string $method
 900          * @return bool
 901          */
 902         public function unlockTables( $method ) {
 903                 $this->query( "UNLOCK TABLES", $method );
 904
 905                 return true;
 906         }
 907
 908         /**
 909          * Get search engine class. All subclasses of this
 910          * need to implement this if they wish to use searching.
 911          *
 912          * @return string
 913          */
 914         public function getSearchEngine() {
 915                 return 'SearchMySQL';
 916         }
 917
 918         /**
 919          * @param bool $value
 920          */
 921         public function setBigSelects( $value = true ) {
 922                 if ( $value === 'default' ) {
 923                         if ( $this->mDefaultBigSelects === null ) {
 924                                 # Function hasn't been called before so it must already be set to the default
 925                                 return;
 926                         } else {
 927                                 $value = $this->mDefaultBigSelects;
 928                         }
 929                 } elseif ( $this->mDefaultBigSelects === null ) {
 930                         $this->mDefaultBigSelects = (bool)$this->selectField( false, '@@sql_big_selects' );
 931                 }
 932                 $encValue = $value ? '1' : '0';
 933                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
 934         }
 935
 936         /**
 937          * DELETE where the condition is a join. MySql uses multi-table deletes.
 938          * @param string $delTable
 939          * @param string $joinTable
 940          * @param string $delVar
 941          * @param string $joinVar
 942          * @param array|string $conds
 943          * @param bool|string $fname
 944          * @throws DBUnexpectedError
 945          * @return bool|ResultWrapper
 946          */
 947         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) {
 948                 if ( !$conds ) {
 949                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
 950                 }
 951
 952                 $delTable = $this->tableName( $delTable );
 953                 $joinTable = $this->tableName( $joinTable );
 954                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
 955
 956                 if ( $conds != '*' ) {
 957                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
 958                 }
 959
 960                 return $this->query( $sql, $fname );
 961         }
 962
 963         /**
 964          * @param string $table
 965          * @param array $rows
 966          * @param array $uniqueIndexes
 967          * @param array $set
 968          * @param string $fname
 969          * @return bool
 970          */
 971         public function upsert( $table, array $rows, array $uniqueIndexes,
 972                 array $set, $fname = __METHOD__
 973         ) {
 974                 if ( !count( $rows ) ) {
 975                         return true; // nothing to do
 976                 }
 977
 978                 if ( !is_array( reset( $rows ) ) ) {
 979                         $rows = array( $rows );
 980                 }
 981
 982                 $table = $this->tableName( $table );
 983                 $columns = array_keys( $rows[0] );
 984
 985                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
 986                 $rowTuples = array();
 987                 foreach ( $rows as $row ) {
 988                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
 989                 }
 990                 $sql .= implode( ',', $rowTuples );
 991                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, LIST_SET );
 992
 993                 return (bool)$this->query( $sql, $fname );
 994         }
 995
 996         /**
 997          * Determines how long the server has been up
 998          *
 999          * @return int
1000          */
1001         function getServerUptime() {
1002                 $vars = $this->getMysqlStatus( 'Uptime' );
1003
1004                 return (int)$vars['Uptime'];
1005         }
1006
1007         /**
1008          * Determines if the last failure was due to a deadlock
1009          *
1010          * @return bool
1011          */
1012         function wasDeadlock() {
1013                 return $this->lastErrno() == 1213;
1014         }
1015
1016         /**
1017          * Determines if the last failure was due to a lock timeout
1018          *
1019          * @return bool
1020          */
1021         function wasLockTimeout() {
1022                 return $this->lastErrno() == 1205;
1023         }
1024
1025         /**
1026          * Determines if the last query error was something that should be dealt
1027          * with by pinging the connection and reissuing the query
1028          *
1029          * @return bool
1030          */
1031         function wasErrorReissuable() {
1032                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
1033         }
1034
1035         /**
1036          * Determines if the last failure was due to the database being read-only.
1037          *
1038          * @return bool
1039          */
1040         function wasReadOnlyError() {
1041                 return $this->lastErrno() == 1223 ||
1042                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1043         }
1044
1045         /**
1046          * @param string $oldName
1047          * @param string $newName
1048          * @param bool $temporary
1049          * @param string $fname
1050          * @return bool
1051          */
1052         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1053                 $tmp = $temporary ? 'TEMPORARY ' : '';
1054                 $newName = $this->addIdentifierQuotes( $newName );
1055                 $oldName = $this->addIdentifierQuotes( $oldName );
1056                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1057
1058                 return $this->query( $query, $fname );
1059         }
1060
1061         /**
1062          * List all tables on the database
1063          *
1064          * @param string $prefix Only show tables with this prefix, e.g. mw_
1065          * @param string $fname Calling function name
1066          * @return array
1067          */
1068         function listTables( $prefix = null, $fname = __METHOD__ ) {
1069                 $result = $this->query( "SHOW TABLES", $fname );
1070
1071                 $endArray = array();
1072
1073                 foreach ( $result as $table ) {
1074                         $vars = get_object_vars( $table );
1075                         $table = array_pop( $vars );
1076
1077                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1078                                 $endArray[] = $table;
1079                         }
1080                 }
1081
1082                 return $endArray;
1083         }
1084
1085         /**
1086          * @param string $tableName
1087          * @param string $fName
1088          * @return bool|ResultWrapper
1089          */
1090         public function dropTable( $tableName, $fName = __METHOD__ ) {
1091                 if ( !$this->tableExists( $tableName, $fName ) ) {
1092                         return false;
1093                 }
1094
1095                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1096         }
1097
1098         /**
1099          * @return array
1100          */
1101         protected function getDefaultSchemaVars() {
1102                 $vars = parent::getDefaultSchemaVars();
1103                 $vars['wgDBTableOptions'] = str_replace( 'TYPE', 'ENGINE', $GLOBALS['wgDBTableOptions'] );
1104                 $vars['wgDBTableOptions'] = str_replace(
1105                         'CHARSET=mysql4',
1106                         'CHARSET=binary',
1107                         $vars['wgDBTableOptions']
1108                 );
1109
1110                 return $vars;
1111         }
1112
1113         /**
1114          * Get status information from SHOW STATUS in an associative array
1115          *
1116          * @param string $which
1117          * @return array
1118          */
1119         function getMysqlStatus( $which = "%" ) {
1120                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1121                 $status = array();
1122
1123                 foreach ( $res as $row ) {
1124                         $status[$row->Variable_name] = $row->Value;
1125                 }
1126
1127                 return $status;
1128         }
1129
1130         /**
1131          * Lists VIEWs in the database
1132          *
1133          * @param string $prefix Only show VIEWs with this prefix, eg.
1134          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1135          * @param string $fname Name of calling function
1136          * @return array
1137          * @since 1.22
1138          */
1139         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1140
1141                 if ( !isset( $this->allViews ) ) {
1142
1143                         // The name of the column containing the name of the VIEW
1144                         $propertyName = 'Tables_in_' . $this->mDBname;
1145
1146                         // Query for the VIEWS
1147                         $result = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1148                         $this->allViews = array();
1149                         while ( ( $row = $this->fetchRow( $result ) ) !== false ) {
1150                                 array_push( $this->allViews, $row[$propertyName] );
1151                         }
1152                 }
1153
1154                 if ( is_null( $prefix ) || $prefix === '' ) {
1155                         return $this->allViews;
1156                 }
1157
1158                 $filteredViews = array();
1159                 foreach ( $this->allViews as $viewName ) {
1160                         // Does the name of this VIEW start with the table-prefix?
1161                         if ( strpos( $viewName, $prefix ) === 0 ) {
1162                                 array_push( $filteredViews, $viewName );
1163                         }
1164                 }
1165
1166                 return $filteredViews;
1167         }
1168
1169         /**
1170          * Differentiates between a TABLE and a VIEW.
1171          *
1172          * @param string $name Name of the TABLE/VIEW to test
1173          * @param string $prefix
1174          * @return bool
1175          * @since 1.22
1176          */
1177         public function isView( $name, $prefix = null ) {
1178                 return in_array( $name, $this->listViews( $prefix ) );
1179         }
1180 }
1181
1182 /**
1183  * Utility class.
1184  * @ingroup Database
1185  */
1186 class MySQLField implements Field {
1187         private $name, $tablename, $default, $max_length, $nullable,
1188                 $is_pk, $is_unique, $is_multiple, $is_key, $type, $binary;
1189
1190         function __construct( $info ) {
1191                 $this->name = $info->name;
1192                 $this->tablename = $info->table;
1193                 $this->default = $info->def;
1194                 $this->max_length = $info->max_length;
1195                 $this->nullable = !$info->not_null;
1196                 $this->is_pk = $info->primary_key;
1197                 $this->is_unique = $info->unique_key;
1198                 $this->is_multiple = $info->multiple_key;
1199                 $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
1200                 $this->type = $info->type;
1201                 $this->binary = isset( $info->binary ) ? $info->binary : false;
1202         }
1203
1204         /**
1205          * @return string
1206          */
1207         function name() {
1208                 return $this->name;
1209         }
1210
1211         /**
1212          * @return string
1213          */
1214         function tableName() {
1215                 return $this->tableName;
1216         }
1217
1218         /**
1219          * @return string
1220          */
1221         function type() {
1222                 return $this->type;
1223         }
1224
1225         /**
1226          * @return bool
1227          */
1228         function isNullable() {
1229                 return $this->nullable;
1230         }
1231
1232         function defaultValue() {
1233                 return $this->default;
1234         }
1235
1236         /**
1237          * @return bool
1238          */
1239         function isKey() {
1240                 return $this->is_key;
1241         }
1242
1243         /**
1244          * @return bool
1245          */
1246         function isMultipleKey() {
1247                 return $this->is_multiple;
1248         }
1249
1250         function isBinary() {
1251                 return $this->binary;
1252         }
1253 }
1254
1255 class MySQLMasterPos implements DBMasterPos {
1256         /** @var string */
1257         public $file;
1258
1259         /** @var int Timestamp */
1260         public $pos;
1261
1262         function __construct( $file, $pos ) {
1263                 $this->file = $file;
1264                 $this->pos = $pos;
1265         }
1266
1267         function __toString() {
1268                 // e.g db1034-bin.000976/843431247
1269                 return "{$this->file}/{$this->pos}";
1270         }
1271
1272         /**
1273          * @return array|bool (int, int)
1274          */
1275         protected function getCoordinates() {
1276                 $m = array();
1277                 if ( preg_match( '!\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
1278                         return array( (int)$m[1], (int)$m[2] );
1279                 }
1280
1281                 return false;
1282         }
1283
1284         function hasReached( MySQLMasterPos $pos ) {
1285                 $thisPos = $this->getCoordinates();
1286                 $thatPos = $pos->getCoordinates();
1287
1288                 return ( $thisPos && $thatPos && $thisPos >= $thatPos );
1289         }
1290 }