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
  62                 # Debugging hack -- fake cluster
  63                 if ( $wgAllDBsAreLocalhost ) {
  64                         $realServer = 'localhost';
  65                 } else {
  66                         $realServer = $server;
  67                 }
  68                 $this->close();
  69                 $this->mServer = $server;
  70                 $this->mUser = $user;
  71                 $this->mPassword = $password;
  72                 $this->mDBname = $dbName;
  73
  74                 # The kernel's default SYN retransmission period is far too slow for us,
  75                 # so we use a short timeout plus a manual retry. Retrying means that a small
  76                 # but finite rate of SYN packet loss won't cause user-visible errors.
  77                 $this->mConn = false;
  78                 $this->installErrorHandler();
  79                 try {
  80                         $this->mConn = $this->mysqlConnect( $realServer );
  81                 } catch ( Exception $ex ) {
  82                         $this->restoreErrorHandler();
  83                         throw $ex;
  84                 }
  85                 $error = $this->restoreErrorHandler();
  86
  87                 # Always log connection errors
  88                 if ( !$this->mConn ) {
  89                         if ( !$error ) {
  90                                 $error = $this->lastError();
  91                         }
  92                         wfLogDBError(
  93                                 "Error connecting to {db_server}: {error}",
  94                                 $this->getLogContext( array(
  95                                         'method' => __METHOD__,
  96                                         'error' => $error,
  97                                 ) )
  98                         );
  99                         wfDebug( "DB connection error\n" .
 100                                 "Server: $server, User: $user, Password: " .
 101                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 102
 103                         $this->reportConnectionError( $error );
 104                 }
 105
 106                 if ( $dbName != '' ) {
 107                         wfSuppressWarnings();
 108                         $success = $this->selectDB( $dbName );
 109                         wfRestoreWarnings();
 110                         if ( !$success ) {
 111                                 wfLogDBError(
 112                                         "Error selecting database {db_name} on server {db_server}",
 113                                         $this->getLogContext( array(
 114                                                 'method' => __METHOD__,
 115                                         ) )
 116                                 );
 117                                 wfDebug( "Error selecting database $dbName on server {$this->mServer} " .
 118                                         "from client host " . wfHostname() . "\n" );
 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(
 136                                         "Error setting sql_mode to $mode on server {db_server}",
 137                                         $this->getLogContext( array(
 138                                                 'method' => __METHOD__,
 139                                         ) )
 140                                 );
 141                                 $this->reportConnectionError( "Error setting sql_mode to $mode" );
 142                         }
 143                 }
 144
 145                 $this->mOpened = true;
 146
 147                 return true;
 148         }
 149
 150         /**
 151          * Set the character set information right after connection
 152          * @return bool
 153          */
 154         protected function connectInitCharset() {
 155                 global $wgDBmysql5;
 156
 157                 if ( $wgDBmysql5 ) {
 158                         // Tell the server we're communicating with it in UTF-8.
 159                         // This may engage various charset conversions.
 160                         return $this->mysqlSetCharset( 'utf8' );
 161                 } else {
 162                         return $this->mysqlSetCharset( 'binary' );
 163                 }
 164         }
 165
 166         /**
 167          * Open a connection to a MySQL server
 168          *
 169          * @param string $realServer
 170          * @return mixed Raw connection
 171          * @throws DBConnectionError
 172          */
 173         abstract protected function mysqlConnect( $realServer );
 174
 175         /**
 176          * Set the character set of the MySQL link
 177          *
 178          * @param string $charset
 179          * @return bool
 180          */
 181         abstract protected function mysqlSetCharset( $charset );
 182
 183         /**
 184          * @param ResultWrapper|resource $res
 185          * @throws DBUnexpectedError
 186          */
 187         function freeResult( $res ) {
 188                 if ( $res instanceof ResultWrapper ) {
 189                         $res = $res->result;
 190                 }
 191                 wfSuppressWarnings();
 192                 $ok = $this->mysqlFreeResult( $res );
 193                 wfRestoreWarnings();
 194                 if ( !$ok ) {
 195                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 196                 }
 197         }
 198
 199         /**
 200          * Free result memory
 201          *
 202          * @param resource $res Raw result
 203          * @return bool
 204          */
 205         abstract protected function mysqlFreeResult( $res );
 206
 207         /**
 208          * @param ResultWrapper|resource $res
 209          * @return stdClass|bool
 210          * @throws DBUnexpectedError
 211          */
 212         function fetchObject( $res ) {
 213                 if ( $res instanceof ResultWrapper ) {
 214                         $res = $res->result;
 215                 }
 216                 wfSuppressWarnings();
 217                 $row = $this->mysqlFetchObject( $res );
 218                 wfRestoreWarnings();
 219
 220                 $errno = $this->lastErrno();
 221                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 222                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 223                 // these are the only errors mysql_fetch_object can cause.
 224                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 225                 if ( $errno == 2000 || $errno == 2013 ) {
 226                         throw new DBUnexpectedError(
 227                                 $this,
 228                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 229                         );
 230                 }
 231
 232                 return $row;
 233         }
 234
 235         /**
 236          * Fetch a result row as an object
 237          *
 238          * @param resource $res Raw result
 239          * @return stdClass
 240          */
 241         abstract protected function mysqlFetchObject( $res );
 242
 243         /**
 244          * @param ResultWrapper|resource $res
 245          * @return array|bool
 246          * @throws DBUnexpectedError
 247          */
 248         function fetchRow( $res ) {
 249                 if ( $res instanceof ResultWrapper ) {
 250                         $res = $res->result;
 251                 }
 252                 wfSuppressWarnings();
 253                 $row = $this->mysqlFetchArray( $res );
 254                 wfRestoreWarnings();
 255
 256                 $errno = $this->lastErrno();
 257                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 258                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 259                 // these are the only errors mysql_fetch_array can cause.
 260                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 261                 if ( $errno == 2000 || $errno == 2013 ) {
 262                         throw new DBUnexpectedError(
 263                                 $this,
 264                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 265                         );
 266                 }
 267
 268                 return $row;
 269         }
 270
 271         /**
 272          * Fetch a result row as an associative and numeric array
 273          *
 274          * @param resource $res Raw result
 275          * @return array
 276          */
 277         abstract protected function mysqlFetchArray( $res );
 278
 279         /**
 280          * @throws DBUnexpectedError
 281          * @param ResultWrapper|resource $res
 282          * @return int
 283          */
 284         function numRows( $res ) {
 285                 if ( $res instanceof ResultWrapper ) {
 286                         $res = $res->result;
 287                 }
 288                 wfSuppressWarnings();
 289                 $n = $this->mysqlNumRows( $res );
 290                 wfRestoreWarnings();
 291
 292                 // Unfortunately, mysql_num_rows does not reset the last errno.
 293                 // We are not checking for any errors here, since
 294                 // these are no errors mysql_num_rows can cause.
 295                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 296                 // See https://bugzilla.wikimedia.org/42430
 297                 return $n;
 298         }
 299
 300         /**
 301          * Get number of rows in result
 302          *
 303          * @param resource $res Raw result
 304          * @return int
 305          */
 306         abstract protected function mysqlNumRows( $res );
 307
 308         /**
 309          * @param ResultWrapper|resource $res
 310          * @return int
 311          */
 312         function numFields( $res ) {
 313                 if ( $res instanceof ResultWrapper ) {
 314                         $res = $res->result;
 315                 }
 316
 317                 return $this->mysqlNumFields( $res );
 318         }
 319
 320         /**
 321          * Get number of fields in result
 322          *
 323          * @param resource $res Raw result
 324          * @return int
 325          */
 326         abstract protected function mysqlNumFields( $res );
 327
 328         /**
 329          * @param ResultWrapper|resource $res
 330          * @param int $n
 331          * @return string
 332          */
 333         function fieldName( $res, $n ) {
 334                 if ( $res instanceof ResultWrapper ) {
 335                         $res = $res->result;
 336                 }
 337
 338                 return $this->mysqlFieldName( $res, $n );
 339         }
 340
 341         /**
 342          * Get the name of the specified field in a result
 343          *
 344          * @param ResultWrapper|resource $res
 345          * @param int $n
 346          * @return string
 347          */
 348         abstract protected function mysqlFieldName( $res, $n );
 349
 350         /**
 351          * mysql_field_type() wrapper
 352          * @param ResultWrapper|resource $res
 353          * @param int $n
 354          * @return string
 355          */
 356         public function fieldType( $res, $n ) {
 357                 if ( $res instanceof ResultWrapper ) {
 358                         $res = $res->result;
 359                 }
 360
 361                 return $this->mysqlFieldType( $res, $n );
 362         }
 363
 364         /**
 365          * Get the type of the specified field in a result
 366          *
 367          * @param ResultWrapper|resource $res
 368          * @param int $n
 369          * @return string
 370          */
 371         abstract protected function mysqlFieldType( $res, $n );
 372
 373         /**
 374          * @param ResultWrapper|resource $res
 375          * @param int $row
 376          * @return bool
 377          */
 378         function dataSeek( $res, $row ) {
 379                 if ( $res instanceof ResultWrapper ) {
 380                         $res = $res->result;
 381                 }
 382
 383                 return $this->mysqlDataSeek( $res, $row );
 384         }
 385
 386         /**
 387          * Move internal result pointer
 388          *
 389          * @param ResultWrapper|resource $res
 390          * @param int $row
 391          * @return bool
 392          */
 393         abstract protected function mysqlDataSeek( $res, $row );
 394
 395         /**
 396          * @return string
 397          */
 398         function lastError() {
 399                 if ( $this->mConn ) {
 400                         # Even if it's non-zero, it can still be invalid
 401                         wfSuppressWarnings();
 402                         $error = $this->mysqlError( $this->mConn );
 403                         if ( !$error ) {
 404                                 $error = $this->mysqlError();
 405                         }
 406                         wfRestoreWarnings();
 407                 } else {
 408                         $error = $this->mysqlError();
 409                 }
 410                 if ( $error ) {
 411                         $error .= ' (' . $this->mServer . ')';
 412                 }
 413
 414                 return $error;
 415         }
 416
 417         /**
 418          * Returns the text of the error message from previous MySQL operation
 419          *
 420          * @param resource $conn Raw connection
 421          * @return string
 422          */
 423         abstract protected function mysqlError( $conn = null );
 424
 425         /**
 426          * @param string $table
 427          * @param array $uniqueIndexes
 428          * @param array $rows
 429          * @param string $fname
 430          * @return ResultWrapper
 431          */
 432         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 433                 return $this->nativeReplace( $table, $rows, $fname );
 434         }
 435
 436         /**
 437          * Estimate rows in dataset
 438          * Returns estimated count, based on EXPLAIN output
 439          * Takes same arguments as Database::select()
 440          *
 441          * @param string|array $table
 442          * @param string|array $vars
 443          * @param string|array $conds
 444          * @param string $fname
 445          * @param string|array $options
 446          * @return bool|int
 447          */
 448         public function estimateRowCount( $table, $vars = '*', $conds = '',
 449                 $fname = __METHOD__, $options = array()
 450         ) {
 451                 $options['EXPLAIN'] = true;
 452                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 453                 if ( $res === false ) {
 454                         return false;
 455                 }
 456                 if ( !$this->numRows( $res ) ) {
 457                         return 0;
 458                 }
 459
 460                 $rows = 1;
 461                 foreach ( $res as $plan ) {
 462                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 463                 }
 464
 465                 return $rows;
 466         }
 467
 468         /**
 469          * @param string $table
 470          * @param string $field
 471          * @return bool|MySQLField
 472          */
 473         function fieldInfo( $table, $field ) {
 474                 $table = $this->tableName( $table );
 475                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 476                 if ( !$res ) {
 477                         return false;
 478                 }
 479                 $n = $this->mysqlNumFields( $res->result );
 480                 for ( $i = 0; $i < $n; $i++ ) {
 481                         $meta = $this->mysqlFetchField( $res->result, $i );
 482                         if ( $field == $meta->name ) {
 483                                 return new MySQLField( $meta );
 484                         }
 485                 }
 486
 487                 return false;
 488         }
 489
 490         /**
 491          * Get column information from a result
 492          *
 493          * @param resource $res Raw result
 494          * @param int $n
 495          * @return stdClass
 496          */
 497         abstract protected function mysqlFetchField( $res, $n );
 498
 499         /**
 500          * Get information about an index into an object
 501          * Returns false if the index does not exist
 502          *
 503          * @param string $table
 504          * @param string $index
 505          * @param string $fname
 506          * @return bool|array|null False or null on failure
 507          */
 508         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 509                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 510                 # SHOW INDEX should work for 3.x and up:
 511                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 512                 $table = $this->tableName( $table );
 513                 $index = $this->indexName( $index );
 514
 515                 $sql = 'SHOW INDEX FROM ' . $table;
 516                 $res = $this->query( $sql, $fname );
 517
 518                 if ( !$res ) {
 519                         return null;
 520                 }
 521
 522                 $result = array();
 523
 524                 foreach ( $res as $row ) {
 525                         if ( $row->Key_name == $index ) {
 526                                 $result[] = $row;
 527                         }
 528                 }
 529
 530                 return empty( $result ) ? false : $result;
 531         }
 532
 533         /**
 534          * @param string $s
 535          * @return string
 536          */
 537         function strencode( $s ) {
 538                 $sQuoted = $this->mysqlRealEscapeString( $s );
 539
 540                 if ( $sQuoted === false ) {
 541                         $this->ping();
 542                         $sQuoted = $this->mysqlRealEscapeString( $s );
 543                 }
 544
 545                 return $sQuoted;
 546         }
 547
 548         /**
 549          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 550          *
 551          * @param string $s
 552          * @return string
 553          */
 554         public function addIdentifierQuotes( $s ) {
 555                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 556                 // Remove NUL bytes and escape backticks by doubling
 557                 return '`' . str_replace( array( "\0", '`' ), array( '', '``' ), $s ) . '`';
 558         }
 559
 560         /**
 561          * @param string $name
 562          * @return bool
 563          */
 564         public function isQuotedIdentifier( $name ) {
 565                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 566         }
 567
 568         /**
 569          * @return bool
 570          */
 571         function ping() {
 572                 $ping = $this->mysqlPing();
 573                 if ( $ping ) {
 574                         return true;
 575                 }
 576
 577                 $this->closeConnection();
 578                 $this->mOpened = false;
 579                 $this->mConn = false;
 580                 $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
 581
 582                 return true;
 583         }
 584
 585         /**
 586          * Ping a server connection or reconnect if there is no connection
 587          *
 588          * @return bool
 589          */
 590         abstract protected function mysqlPing();
 591
 592         /**
 593          * Set lag time in seconds for a fake slave
 594          *
 595          * @param int $lag
 596          */
 597         public function setFakeSlaveLag( $lag ) {
 598                 $this->mFakeSlaveLag = $lag;
 599         }
 600
 601         /**
 602          * Make this connection a fake master
 603          *
 604          * @param bool $enabled
 605          */
 606         public function setFakeMaster( $enabled = true ) {
 607                 $this->mFakeMaster = $enabled;
 608         }
 609
 610         /**
 611          * Returns slave lag.
 612          *
 613          * This will do a SHOW SLAVE STATUS
 614          *
 615          * @return int
 616          */
 617         function getLag() {
 618                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 619                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
 620
 621                         return $this->mFakeSlaveLag;
 622                 }
 623
 624                 return $this->getLagFromSlaveStatus();
 625         }
 626
 627         /**
 628          * @return bool|int
 629          */
 630         function getLagFromSlaveStatus() {
 631                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 632                 if ( !$res ) {
 633                         return false;
 634                 }
 635                 $row = $res->fetchObject();
 636                 if ( !$row ) {
 637                         return false;
 638                 }
 639                 if ( strval( $row->Seconds_Behind_Master ) === '' ) {
 640                         return false;
 641                 } else {
 642                         return intval( $row->Seconds_Behind_Master );
 643                 }
 644         }
 645
 646         /**
 647          * Wait for the slave to catch up to a given master position.
 648          * @todo Return values for this and base class are rubbish
 649          *
 650          * @param DBMasterPos|MySQLMasterPos $pos
 651          * @param int $timeout The maximum number of seconds to wait for synchronisation
 652          * @return int Zero if the slave was past that position already,
 653          *   greater than zero if we waited for some period of time, less than
 654          *   zero if we timed out.
 655          */
 656         function masterPosWait( DBMasterPos $pos, $timeout ) {
 657                 if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
 658                         return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 659                 }
 660
 661                 # Commit any open transactions
 662                 $this->commit( __METHOD__, 'flush' );
 663
 664                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 665                         $wait = intval( ( $pos->pos - microtime( true ) + $this->mFakeSlaveLag ) * 1e6 );
 666
 667                         if ( $wait > $timeout * 1e6 ) {
 668                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
 669
 670                                 return -1;
 671                         } elseif ( $wait > 0 ) {
 672                                 wfDebug( "Fake slave waiting $wait us\n" );
 673                                 usleep( $wait );
 674
 675                                 return 1;
 676                         } else {
 677                                 wfDebug( "Fake slave up to date ($wait us)\n" );
 678
 679                                 return 0;
 680                         }
 681                 }
 682
 683                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 684                 $encFile = $this->addQuotes( $pos->file );
 685                 $encPos = intval( $pos->pos );
 686                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 687                 $res = $this->doQuery( $sql );
 688
 689                 $status = false;
 690                 if ( $res && $row = $this->fetchRow( $res ) ) {
 691                         $status = $row[0]; // can be NULL, -1, or 0+ per the MySQL manual
 692                         if ( ctype_digit( $status ) ) { // success
 693                                 $this->lastKnownSlavePos = $pos;
 694                         }
 695                 }
 696
 697                 return $status;
 698         }
 699
 700         /**
 701          * Get the position of the master from SHOW SLAVE STATUS
 702          *
 703          * @return MySQLMasterPos|bool
 704          */
 705         function getSlavePos() {
 706                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 707                         $pos = new MySQLMasterPos( 'fake', microtime( true ) - $this->mFakeSlaveLag );
 708                         wfDebug( __METHOD__ . ": fake slave pos = $pos\n" );
 709
 710                         return $pos;
 711                 }
 712
 713                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
 714                 $row = $this->fetchObject( $res );
 715
 716                 if ( $row ) {
 717                         $pos = isset( $row->Exec_master_log_pos )
 718                                 ? $row->Exec_master_log_pos
 719                                 : $row->Exec_Master_Log_Pos;
 720
 721                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
 722                 } else {
 723                         return false;
 724                 }
 725         }
 726
 727         /**
 728          * Get the position of the master from SHOW MASTER STATUS
 729          *
 730          * @return MySQLMasterPos|bool
 731          */
 732         function getMasterPos() {
 733                 if ( $this->mFakeMaster ) {
 734                         return new MySQLMasterPos( 'fake', microtime( true ) );
 735                 }
 736
 737                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
 738                 $row = $this->fetchObject( $res );
 739
 740                 if ( $row ) {
 741                         return new MySQLMasterPos( $row->File, $row->Position );
 742                 } else {
 743                         return false;
 744                 }
 745         }
 746
 747         /**
 748          * @param string $index
 749          * @return string
 750          */
 751         function useIndexClause( $index ) {
 752                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 753         }
 754
 755         /**
 756          * @return string
 757          */
 758         function lowPriorityOption() {
 759                 return 'LOW_PRIORITY';
 760         }
 761
 762         /**
 763          * @return string
 764          */
 765         public function getSoftwareLink() {
 766                 // MariaDB includes its name in its version string; this is how MariaDB's version of
 767                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
 768                 // in libmysql/libmysql.c).
 769                 $version = $this->getServerVersion();
 770                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 771                         return '[{{int:version-db-mariadb-url}} MariaDB]';
 772                 }
 773
 774                 // Percona Server's version suffix is not very distinctive, and @@version_comment
 775                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
 776                 // (Even Percona's version of mysql doesn't try to make the distinction.)
 777                 return '[{{int:version-db-mysql-url}} MySQL]';
 778         }
 779
 780         /**
 781          * @return string
 782          */
 783         public function getServerVersion() {
 784                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
 785                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
 786                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
 787                 if ( $this->serverVersion === null ) {
 788                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
 789                 }
 790                 return $this->serverVersion;
 791         }
 792
 793         /**
 794          * @param array $options
 795          */
 796         public function setSessionOptions( array $options ) {
 797                 if ( isset( $options['connTimeout'] ) ) {
 798                         $timeout = (int)$options['connTimeout'];
 799                         $this->query( "SET net_read_timeout=$timeout" );
 800                         $this->query( "SET net_write_timeout=$timeout" );
 801                 }
 802         }
 803
 804         /**
 805          * @param string $sql
 806          * @param string $newLine
 807          * @return bool
 808          */
 809         public function streamStatementEnd( &$sql, &$newLine ) {
 810                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 811                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 812                         $this->delimiter = $m[1];
 813                         $newLine = '';
 814                 }
 815
 816                 return parent::streamStatementEnd( $sql, $newLine );
 817         }
 818
 819         /**
 820          * Check to see if a named lock is available. This is non-blocking.
 821          *
 822          * @param string $lockName Name of lock to poll
 823          * @param string $method Name of method calling us
 824          * @return bool
 825          * @since 1.20
 826          */
 827         public function lockIsFree( $lockName, $method ) {
 828                 $lockName = $this->addQuotes( $lockName );
 829                 $result = $this->query( "SELECT IS_FREE_LOCK($lockName) AS lockstatus", $method );
 830                 $row = $this->fetchObject( $result );
 831
 832                 return ( $row->lockstatus == 1 );
 833         }
 834
 835         /**
 836          * @param string $lockName
 837          * @param string $method
 838          * @param int $timeout
 839          * @return bool
 840          */
 841         public function lock( $lockName, $method, $timeout = 5 ) {
 842                 $lockName = $this->addQuotes( $lockName );
 843                 $result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
 844                 $row = $this->fetchObject( $result );
 845
 846                 if ( $row->lockstatus == 1 ) {
 847                         return true;
 848                 } else {
 849                         wfDebug( __METHOD__ . " failed to acquire lock\n" );
 850
 851                         return false;
 852                 }
 853         }
 854
 855         /**
 856          * FROM MYSQL DOCS:
 857          * http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
 858          * @param string $lockName
 859          * @param string $method
 860          * @return bool
 861          */
 862         public function unlock( $lockName, $method ) {
 863                 $lockName = $this->addQuotes( $lockName );
 864                 $result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
 865                 $row = $this->fetchObject( $result );
 866
 867                 return ( $row->lockstatus == 1 );
 868         }
 869
 870         /**
 871          * @param array $read
 872          * @param array $write
 873          * @param string $method
 874          * @param bool $lowPriority
 875          * @return bool
 876          */
 877         public function lockTables( $read, $write, $method, $lowPriority = true ) {
 878                 $items = array();
 879
 880                 foreach ( $write as $table ) {
 881                         $tbl = $this->tableName( $table ) .
 882                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
 883                                 ' WRITE';
 884                         $items[] = $tbl;
 885                 }
 886                 foreach ( $read as $table ) {
 887                         $items[] = $this->tableName( $table ) . ' READ';
 888                 }
 889                 $sql = "LOCK TABLES " . implode( ',', $items );
 890                 $this->query( $sql, $method );
 891
 892                 return true;
 893         }
 894
 895         /**
 896          * @param string $method
 897          * @return bool
 898          */
 899         public function unlockTables( $method ) {
 900                 $this->query( "UNLOCK TABLES", $method );
 901
 902                 return true;
 903         }
 904
 905         /**
 906          * Get search engine class. All subclasses of this
 907          * need to implement this if they wish to use searching.
 908          *
 909          * @return string
 910          */
 911         public function getSearchEngine() {
 912                 return 'SearchMySQL';
 913         }
 914
 915         /**
 916          * @param bool $value
 917          */
 918         public function setBigSelects( $value = true ) {
 919                 if ( $value === 'default' ) {
 920                         if ( $this->mDefaultBigSelects === null ) {
 921                                 # Function hasn't been called before so it must already be set to the default
 922                                 return;
 923                         } else {
 924                                 $value = $this->mDefaultBigSelects;
 925                         }
 926                 } elseif ( $this->mDefaultBigSelects === null ) {
 927                         $this->mDefaultBigSelects = (bool)$this->selectField( false, '@@sql_big_selects' );
 928                 }
 929                 $encValue = $value ? '1' : '0';
 930                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
 931         }
 932
 933         /**
 934          * DELETE where the condition is a join. MySql uses multi-table deletes.
 935          * @param string $delTable
 936          * @param string $joinTable
 937          * @param string $delVar
 938          * @param string $joinVar
 939          * @param array|string $conds
 940          * @param bool|string $fname
 941          * @throws DBUnexpectedError
 942          * @return bool|ResultWrapper
 943          */
 944         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) {
 945                 if ( !$conds ) {
 946                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
 947                 }
 948
 949                 $delTable = $this->tableName( $delTable );
 950                 $joinTable = $this->tableName( $joinTable );
 951                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
 952
 953                 if ( $conds != '*' ) {
 954                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
 955                 }
 956
 957                 return $this->query( $sql, $fname );
 958         }
 959
 960         /**
 961          * @param string $table
 962          * @param array $rows
 963          * @param array $uniqueIndexes
 964          * @param array $set
 965          * @param string $fname
 966          * @return bool
 967          */
 968         public function upsert( $table, array $rows, array $uniqueIndexes,
 969                 array $set, $fname = __METHOD__
 970         ) {
 971                 if ( !count( $rows ) ) {
 972                         return true; // nothing to do
 973                 }
 974
 975                 if ( !is_array( reset( $rows ) ) ) {
 976                         $rows = array( $rows );
 977                 }
 978
 979                 $table = $this->tableName( $table );
 980                 $columns = array_keys( $rows[0] );
 981
 982                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
 983                 $rowTuples = array();
 984                 foreach ( $rows as $row ) {
 985                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
 986                 }
 987                 $sql .= implode( ',', $rowTuples );
 988                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, LIST_SET );
 989
 990                 return (bool)$this->query( $sql, $fname );
 991         }
 992
 993         /**
 994          * Determines how long the server has been up
 995          *
 996          * @return int
 997          */
 998         function getServerUptime() {
 999                 $vars = $this->getMysqlStatus( 'Uptime' );
1000
1001                 return (int)$vars['Uptime'];
1002         }
1003
1004         /**
1005          * Determines if the last failure was due to a deadlock
1006          *
1007          * @return bool
1008          */
1009         function wasDeadlock() {
1010                 return $this->lastErrno() == 1213;
1011         }
1012
1013         /**
1014          * Determines if the last failure was due to a lock timeout
1015          *
1016          * @return bool
1017          */
1018         function wasLockTimeout() {
1019                 return $this->lastErrno() == 1205;
1020         }
1021
1022         /**
1023          * Determines if the last query error was something that should be dealt
1024          * with by pinging the connection and reissuing the query
1025          *
1026          * @return bool
1027          */
1028         function wasErrorReissuable() {
1029                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
1030         }
1031
1032         /**
1033          * Determines if the last failure was due to the database being read-only.
1034          *
1035          * @return bool
1036          */
1037         function wasReadOnlyError() {
1038                 return $this->lastErrno() == 1223 ||
1039                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1040         }
1041
1042         /**
1043          * @param string $oldName
1044          * @param string $newName
1045          * @param bool $temporary
1046          * @param string $fname
1047          * @return bool
1048          */
1049         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1050                 $tmp = $temporary ? 'TEMPORARY ' : '';
1051                 $newName = $this->addIdentifierQuotes( $newName );
1052                 $oldName = $this->addIdentifierQuotes( $oldName );
1053                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1054
1055                 return $this->query( $query, $fname );
1056         }
1057
1058         /**
1059          * List all tables on the database
1060          *
1061          * @param string $prefix Only show tables with this prefix, e.g. mw_
1062          * @param string $fname Calling function name
1063          * @return array
1064          */
1065         function listTables( $prefix = null, $fname = __METHOD__ ) {
1066                 $result = $this->query( "SHOW TABLES", $fname );
1067
1068                 $endArray = array();
1069
1070                 foreach ( $result as $table ) {
1071                         $vars = get_object_vars( $table );
1072                         $table = array_pop( $vars );
1073
1074                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1075                                 $endArray[] = $table;
1076                         }
1077                 }
1078
1079                 return $endArray;
1080         }
1081
1082         /**
1083          * @param string $tableName
1084          * @param string $fName
1085          * @return bool|ResultWrapper
1086          */
1087         public function dropTable( $tableName, $fName = __METHOD__ ) {
1088                 if ( !$this->tableExists( $tableName, $fName ) ) {
1089                         return false;
1090                 }
1091
1092                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1093         }
1094
1095         /**
1096          * @return array
1097          */
1098         protected function getDefaultSchemaVars() {
1099                 $vars = parent::getDefaultSchemaVars();
1100                 $vars['wgDBTableOptions'] = str_replace( 'TYPE', 'ENGINE', $GLOBALS['wgDBTableOptions'] );
1101                 $vars['wgDBTableOptions'] = str_replace(
1102                         'CHARSET=mysql4',
1103                         'CHARSET=binary',
1104                         $vars['wgDBTableOptions']
1105                 );
1106
1107                 return $vars;
1108         }
1109
1110         /**
1111          * Get status information from SHOW STATUS in an associative array
1112          *
1113          * @param string $which
1114          * @return array
1115          */
1116         function getMysqlStatus( $which = "%" ) {
1117                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1118                 $status = array();
1119
1120                 foreach ( $res as $row ) {
1121                         $status[$row->Variable_name] = $row->Value;
1122                 }
1123
1124                 return $status;
1125         }
1126
1127         /**
1128          * Lists VIEWs in the database
1129          *
1130          * @param string $prefix Only show VIEWs with this prefix, eg.
1131          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1132          * @param string $fname Name of calling function
1133          * @return array
1134          * @since 1.22
1135          */
1136         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1137
1138                 if ( !isset( $this->allViews ) ) {
1139
1140                         // The name of the column containing the name of the VIEW
1141                         $propertyName = 'Tables_in_' . $this->mDBname;
1142
1143                         // Query for the VIEWS
1144                         $result = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1145                         $this->allViews = array();
1146                         while ( ( $row = $this->fetchRow( $result ) ) !== false ) {
1147                                 array_push( $this->allViews, $row[$propertyName] );
1148                         }
1149                 }
1150
1151                 if ( is_null( $prefix ) || $prefix === '' ) {
1152                         return $this->allViews;
1153                 }
1154
1155                 $filteredViews = array();
1156                 foreach ( $this->allViews as $viewName ) {
1157                         // Does the name of this VIEW start with the table-prefix?
1158                         if ( strpos( $viewName, $prefix ) === 0 ) {
1159                                 array_push( $filteredViews, $viewName );
1160                         }
1161                 }
1162
1163                 return $filteredViews;
1164         }
1165
1166         /**
1167          * Differentiates between a TABLE and a VIEW.
1168          *
1169          * @param string $name Name of the TABLE/VIEW to test
1170          * @param string $prefix
1171          * @return bool
1172          * @since 1.22
1173          */
1174         public function isView( $name, $prefix = null ) {
1175                 return in_array( $name, $this->listViews( $prefix ) );
1176         }
1177 }
1178
1179 /**
1180  * Utility class.
1181  * @ingroup Database
1182  */
1183 class MySQLField implements Field {
1184         private $name, $tablename, $default, $max_length, $nullable,
1185                 $is_pk, $is_unique, $is_multiple, $is_key, $type, $binary;
1186
1187         function __construct( $info ) {
1188                 $this->name = $info->name;
1189                 $this->tablename = $info->table;
1190                 $this->default = $info->def;
1191                 $this->max_length = $info->max_length;
1192                 $this->nullable = !$info->not_null;
1193                 $this->is_pk = $info->primary_key;
1194                 $this->is_unique = $info->unique_key;
1195                 $this->is_multiple = $info->multiple_key;
1196                 $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
1197                 $this->type = $info->type;
1198                 $this->binary = isset( $info->binary ) ? $info->binary : false;
1199         }
1200
1201         /**
1202          * @return string
1203          */
1204         function name() {
1205                 return $this->name;
1206         }
1207
1208         /**
1209          * @return string
1210          */
1211         function tableName() {
1212                 return $this->tableName;
1213         }
1214
1215         /**
1216          * @return string
1217          */
1218         function type() {
1219                 return $this->type;
1220         }
1221
1222         /**
1223          * @return bool
1224          */
1225         function isNullable() {
1226                 return $this->nullable;
1227         }
1228
1229         function defaultValue() {
1230                 return $this->default;
1231         }
1232
1233         /**
1234          * @return bool
1235          */
1236         function isKey() {
1237                 return $this->is_key;
1238         }
1239
1240         /**
1241          * @return bool
1242          */
1243         function isMultipleKey() {
1244                 return $this->is_multiple;
1245         }
1246
1247         function isBinary() {
1248                 return $this->binary;
1249         }
1250 }
1251
1252 class MySQLMasterPos implements DBMasterPos {
1253         /** @var string */
1254         public $file;
1255         /** @var int Position */
1256         public $pos;
1257         /** @var float UNIX timestamp */
1258         public $asOfTime = 0.0;
1259
1260         function __construct( $file, $pos ) {
1261                 $this->file = $file;
1262                 $this->pos = $pos;
1263                 $this->asOfTime = microtime( true );
1264         }
1265
1266         function __toString() {
1267                 // e.g db1034-bin.000976/843431247
1268                 return "{$this->file}/{$this->pos}";
1269         }
1270
1271         /**
1272          * @return array|bool (int, int)
1273          */
1274         protected function getCoordinates() {
1275                 $m = array();
1276                 if ( preg_match( '!\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
1277                         return array( (int)$m[1], (int)$m[2] );
1278                 }
1279
1280                 return false;
1281         }
1282
1283         function hasReached( MySQLMasterPos $pos ) {
1284                 $thisPos = $this->getCoordinates();
1285                 $thatPos = $pos->getCoordinates();
1286
1287                 return ( $thisPos && $thatPos && $thisPos >= $thatPos );
1288         }
1289
1290         function asOfTime() {
1291                 return $this->asOfTime;
1292         }
1293 }