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
  75                 # The kernel's default SYN retransmission period is far too slow for us,
  76                 # so we use a short timeout plus a manual retry. Retrying means that a small
  77                 # but finite rate of SYN packet loss won't cause user-visible errors.
  78                 $this->mConn = false;
  79                 $this->installErrorHandler();
  80                 try {
  81                         $this->mConn = $this->mysqlConnect( $realServer );
  82                 } catch ( Exception $ex ) {
  83                         $this->restoreErrorHandler();
  84                         throw $ex;
  85                 }
  86                 $error = $this->restoreErrorHandler();
  87
  88
  89                 # Always log connection errors
  90                 if ( !$this->mConn ) {
  91                         if ( !$error ) {
  92                                 $error = $this->lastError();
  93                         }
  94                         wfLogDBError(
  95                                 "Error connecting to {db_server}: {error}",
  96                                 $this->getLogContext( array(
  97                                         'method' => __METHOD__,
  98                                         'error' => $error,
  99                                 ) )
 100                         );
 101                         wfDebug( "DB connection error\n" .
 102                                 "Server: $server, User: $user, Password: " .
 103                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 104
 105
 106                         $this->reportConnectionError( $error );
 107                 }
 108
 109                 if ( $dbName != '' ) {
 110                         wfSuppressWarnings();
 111                         $success = $this->selectDB( $dbName );
 112                         wfRestoreWarnings();
 113                         if ( !$success ) {
 114                                 wfLogDBError(
 115                                         "Error selecting database {db_name} on server {db_server}",
 116                                         $this->getLogContext( array(
 117                                                 'method' => __METHOD__,
 118                                         ) )
 119                                 );
 120                                 wfDebug( "Error selecting database $dbName on server {$this->mServer} " .
 121                                         "from client host " . wfHostname() . "\n" );
 122
 123
 124                                 $this->reportConnectionError( "Error selecting database $dbName" );
 125                         }
 126                 }
 127
 128                 // Tell the server what we're communicating with
 129                 if ( !$this->connectInitCharset() ) {
 130                         $this->reportConnectionError( "Error setting character set" );
 131                 }
 132
 133                 // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 134                 if ( is_string( $wgSQLMode ) ) {
 135                         $mode = $this->addQuotes( $wgSQLMode );
 136                         // Use doQuery() to avoid opening implicit transactions (DBO_TRX)
 137                         $success = $this->doQuery( "SET sql_mode = $mode", __METHOD__ );
 138                         if ( !$success ) {
 139                                 wfLogDBError(
 140                                         "Error setting sql_mode to $mode on server {db_server}",
 141                                         $this->getLogContext( array(
 142                                                 'method' => __METHOD__,
 143                                         ) )
 144                                 );
 145                                 $this->reportConnectionError( "Error setting sql_mode to $mode" );
 146                         }
 147                 }
 148
 149                 $this->mOpened = true;
 150
 151                 return true;
 152         }
 153
 154         /**
 155          * Set the character set information right after connection
 156          * @return bool
 157          */
 158         protected function connectInitCharset() {
 159                 global $wgDBmysql5;
 160
 161                 if ( $wgDBmysql5 ) {
 162                         // Tell the server we're communicating with it in UTF-8.
 163                         // This may engage various charset conversions.
 164                         return $this->mysqlSetCharset( 'utf8' );
 165                 } else {
 166                         return $this->mysqlSetCharset( 'binary' );
 167                 }
 168         }
 169
 170         /**
 171          * Open a connection to a MySQL server
 172          *
 173          * @param string $realServer
 174          * @return mixed Raw connection
 175          * @throws DBConnectionError
 176          */
 177         abstract protected function mysqlConnect( $realServer );
 178
 179         /**
 180          * Set the character set of the MySQL link
 181          *
 182          * @param string $charset
 183          * @return bool
 184          */
 185         abstract protected function mysqlSetCharset( $charset );
 186
 187         /**
 188          * @param ResultWrapper|resource $res
 189          * @throws DBUnexpectedError
 190          */
 191         function freeResult( $res ) {
 192                 if ( $res instanceof ResultWrapper ) {
 193                         $res = $res->result;
 194                 }
 195                 wfSuppressWarnings();
 196                 $ok = $this->mysqlFreeResult( $res );
 197                 wfRestoreWarnings();
 198                 if ( !$ok ) {
 199                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 200                 }
 201         }
 202
 203         /**
 204          * Free result memory
 205          *
 206          * @param resource $res Raw result
 207          * @return bool
 208          */
 209         abstract protected function mysqlFreeResult( $res );
 210
 211         /**
 212          * @param ResultWrapper|resource $res
 213          * @return stdClass|bool
 214          * @throws DBUnexpectedError
 215          */
 216         function fetchObject( $res ) {
 217                 if ( $res instanceof ResultWrapper ) {
 218                         $res = $res->result;
 219                 }
 220                 wfSuppressWarnings();
 221                 $row = $this->mysqlFetchObject( $res );
 222                 wfRestoreWarnings();
 223
 224                 $errno = $this->lastErrno();
 225                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 226                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 227                 // these are the only errors mysql_fetch_object can cause.
 228                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 229                 if ( $errno == 2000 || $errno == 2013 ) {
 230                         throw new DBUnexpectedError(
 231                                 $this,
 232                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 233                         );
 234                 }
 235
 236                 return $row;
 237         }
 238
 239         /**
 240          * Fetch a result row as an object
 241          *
 242          * @param resource $res Raw result
 243          * @return stdClass
 244          */
 245         abstract protected function mysqlFetchObject( $res );
 246
 247         /**
 248          * @param ResultWrapper|resource $res
 249          * @return array|bool
 250          * @throws DBUnexpectedError
 251          */
 252         function fetchRow( $res ) {
 253                 if ( $res instanceof ResultWrapper ) {
 254                         $res = $res->result;
 255                 }
 256                 wfSuppressWarnings();
 257                 $row = $this->mysqlFetchArray( $res );
 258                 wfRestoreWarnings();
 259
 260                 $errno = $this->lastErrno();
 261                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 262                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 263                 // these are the only errors mysql_fetch_array can cause.
 264                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 265                 if ( $errno == 2000 || $errno == 2013 ) {
 266                         throw new DBUnexpectedError(
 267                                 $this,
 268                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 269                         );
 270                 }
 271
 272                 return $row;
 273         }
 274
 275         /**
 276          * Fetch a result row as an associative and numeric array
 277          *
 278          * @param resource $res Raw result
 279          * @return array
 280          */
 281         abstract protected function mysqlFetchArray( $res );
 282
 283         /**
 284          * @throws DBUnexpectedError
 285          * @param ResultWrapper|resource $res
 286          * @return int
 287          */
 288         function numRows( $res ) {
 289                 if ( $res instanceof ResultWrapper ) {
 290                         $res = $res->result;
 291                 }
 292                 wfSuppressWarnings();
 293                 $n = $this->mysqlNumRows( $res );
 294                 wfRestoreWarnings();
 295
 296                 // Unfortunately, mysql_num_rows does not reset the last errno.
 297                 // We are not checking for any errors here, since
 298                 // these are no errors mysql_num_rows can cause.
 299                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 300                 // See https://bugzilla.wikimedia.org/42430
 301                 return $n;
 302         }
 303
 304         /**
 305          * Get number of rows in result
 306          *
 307          * @param resource $res Raw result
 308          * @return int
 309          */
 310         abstract protected function mysqlNumRows( $res );
 311
 312         /**
 313          * @param ResultWrapper|resource $res
 314          * @return int
 315          */
 316         function numFields( $res ) {
 317                 if ( $res instanceof ResultWrapper ) {
 318                         $res = $res->result;
 319                 }
 320
 321                 return $this->mysqlNumFields( $res );
 322         }
 323
 324         /**
 325          * Get number of fields in result
 326          *
 327          * @param resource $res Raw result
 328          * @return int
 329          */
 330         abstract protected function mysqlNumFields( $res );
 331
 332         /**
 333          * @param ResultWrapper|resource $res
 334          * @param int $n
 335          * @return string
 336          */
 337         function fieldName( $res, $n ) {
 338                 if ( $res instanceof ResultWrapper ) {
 339                         $res = $res->result;
 340                 }
 341
 342                 return $this->mysqlFieldName( $res, $n );
 343         }
 344
 345         /**
 346          * Get the name of the specified field in a result
 347          *
 348          * @param ResultWrapper|resource $res
 349          * @param int $n
 350          * @return string
 351          */
 352         abstract protected function mysqlFieldName( $res, $n );
 353
 354         /**
 355          * mysql_field_type() wrapper
 356          * @param ResultWrapper|resource $res
 357          * @param int $n
 358          * @return string
 359          */
 360         public function fieldType( $res, $n ) {
 361                 if ( $res instanceof ResultWrapper ) {
 362                         $res = $res->result;
 363                 }
 364
 365                 return $this->mysqlFieldType( $res, $n );
 366         }
 367
 368         /**
 369          * Get the type of the specified field in a result
 370          *
 371          * @param ResultWrapper|resource $res
 372          * @param int $n
 373          * @return string
 374          */
 375         abstract protected function mysqlFieldType( $res, $n );
 376
 377         /**
 378          * @param ResultWrapper|resource $res
 379          * @param int $row
 380          * @return bool
 381          */
 382         function dataSeek( $res, $row ) {
 383                 if ( $res instanceof ResultWrapper ) {
 384                         $res = $res->result;
 385                 }
 386
 387                 return $this->mysqlDataSeek( $res, $row );
 388         }
 389
 390         /**
 391          * Move internal result pointer
 392          *
 393          * @param ResultWrapper|resource $res
 394          * @param int $row
 395          * @return bool
 396          */
 397         abstract protected function mysqlDataSeek( $res, $row );
 398
 399         /**
 400          * @return string
 401          */
 402         function lastError() {
 403                 if ( $this->mConn ) {
 404                         # Even if it's non-zero, it can still be invalid
 405                         wfSuppressWarnings();
 406                         $error = $this->mysqlError( $this->mConn );
 407                         if ( !$error ) {
 408                                 $error = $this->mysqlError();
 409                         }
 410                         wfRestoreWarnings();
 411                 } else {
 412                         $error = $this->mysqlError();
 413                 }
 414                 if ( $error ) {
 415                         $error .= ' (' . $this->mServer . ')';
 416                 }
 417
 418                 return $error;
 419         }
 420
 421         /**
 422          * Returns the text of the error message from previous MySQL operation
 423          *
 424          * @param resource $conn Raw connection
 425          * @return string
 426          */
 427         abstract protected function mysqlError( $conn = null );
 428
 429         /**
 430          * @param string $table
 431          * @param array $uniqueIndexes
 432          * @param array $rows
 433          * @param string $fname
 434          * @return ResultWrapper
 435          */
 436         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 437                 return $this->nativeReplace( $table, $rows, $fname );
 438         }
 439
 440         /**
 441          * Estimate rows in dataset
 442          * Returns estimated count, based on EXPLAIN output
 443          * Takes same arguments as Database::select()
 444          *
 445          * @param string|array $table
 446          * @param string|array $vars
 447          * @param string|array $conds
 448          * @param string $fname
 449          * @param string|array $options
 450          * @return bool|int
 451          */
 452         public function estimateRowCount( $table, $vars = '*', $conds = '',
 453                 $fname = __METHOD__, $options = array()
 454         ) {
 455                 $options['EXPLAIN'] = true;
 456                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 457                 if ( $res === false ) {
 458                         return false;
 459                 }
 460                 if ( !$this->numRows( $res ) ) {
 461                         return 0;
 462                 }
 463
 464                 $rows = 1;
 465                 foreach ( $res as $plan ) {
 466                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 467                 }
 468
 469                 return $rows;
 470         }
 471
 472         /**
 473          * @param string $table
 474          * @param string $field
 475          * @return bool|MySQLField
 476          */
 477         function fieldInfo( $table, $field ) {
 478                 $table = $this->tableName( $table );
 479                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 480                 if ( !$res ) {
 481                         return false;
 482                 }
 483                 $n = $this->mysqlNumFields( $res->result );
 484                 for ( $i = 0; $i < $n; $i++ ) {
 485                         $meta = $this->mysqlFetchField( $res->result, $i );
 486                         if ( $field == $meta->name ) {
 487                                 return new MySQLField( $meta );
 488                         }
 489                 }
 490
 491                 return false;
 492         }
 493
 494         /**
 495          * Get column information from a result
 496          *
 497          * @param resource $res Raw result
 498          * @param int $n
 499          * @return stdClass
 500          */
 501         abstract protected function mysqlFetchField( $res, $n );
 502
 503         /**
 504          * Get information about an index into an object
 505          * Returns false if the index does not exist
 506          *
 507          * @param string $table
 508          * @param string $index
 509          * @param string $fname
 510          * @return bool|array|null False or null on failure
 511          */
 512         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 513                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 514                 # SHOW INDEX should work for 3.x and up:
 515                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 516                 $table = $this->tableName( $table );
 517                 $index = $this->indexName( $index );
 518
 519                 $sql = 'SHOW INDEX FROM ' . $table;
 520                 $res = $this->query( $sql, $fname );
 521
 522                 if ( !$res ) {
 523                         return null;
 524                 }
 525
 526                 $result = array();
 527
 528                 foreach ( $res as $row ) {
 529                         if ( $row->Key_name == $index ) {
 530                                 $result[] = $row;
 531                         }
 532                 }
 533
 534                 return empty( $result ) ? false : $result;
 535         }
 536
 537         /**
 538          * @param string $s
 539          * @return string
 540          */
 541         function strencode( $s ) {
 542                 $sQuoted = $this->mysqlRealEscapeString( $s );
 543
 544                 if ( $sQuoted === false ) {
 545                         $this->ping();
 546                         $sQuoted = $this->mysqlRealEscapeString( $s );
 547                 }
 548
 549                 return $sQuoted;
 550         }
 551
 552         /**
 553          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 554          *
 555          * @param string $s
 556          * @return string
 557          */
 558         public function addIdentifierQuotes( $s ) {
 559                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 560                 // Remove NUL bytes and escape backticks by doubling
 561                 return '`' . str_replace( array( "\0", '`' ), array( '', '``' ), $s ) . '`';
 562         }
 563
 564         /**
 565          * @param string $name
 566          * @return bool
 567          */
 568         public function isQuotedIdentifier( $name ) {
 569                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 570         }
 571
 572         /**
 573          * @return bool
 574          */
 575         function ping() {
 576                 $ping = $this->mysqlPing();
 577                 if ( $ping ) {
 578                         return true;
 579                 }
 580
 581                 $this->closeConnection();
 582                 $this->mOpened = false;
 583                 $this->mConn = false;
 584                 $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
 585
 586                 return true;
 587         }
 588
 589         /**
 590          * Ping a server connection or reconnect if there is no connection
 591          *
 592          * @return bool
 593          */
 594         abstract protected function mysqlPing();
 595
 596         /**
 597          * Set lag time in seconds for a fake slave
 598          *
 599          * @param int $lag
 600          */
 601         public function setFakeSlaveLag( $lag ) {
 602                 $this->mFakeSlaveLag = $lag;
 603         }
 604
 605         /**
 606          * Make this connection a fake master
 607          *
 608          * @param bool $enabled
 609          */
 610         public function setFakeMaster( $enabled = true ) {
 611                 $this->mFakeMaster = $enabled;
 612         }
 613
 614         /**
 615          * Returns slave lag.
 616          *
 617          * This will do a SHOW SLAVE STATUS
 618          *
 619          * @return int
 620          */
 621         function getLag() {
 622                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 623                         wfDebug( "getLag: fake slave lagged {$this->mFakeSlaveLag} seconds\n" );
 624
 625                         return $this->mFakeSlaveLag;
 626                 }
 627
 628                 return $this->getLagFromSlaveStatus();
 629         }
 630
 631         /**
 632          * @return bool|int
 633          */
 634         function getLagFromSlaveStatus() {
 635                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 636                 if ( !$res ) {
 637                         return false;
 638                 }
 639                 $row = $res->fetchObject();
 640                 if ( !$row ) {
 641                         return false;
 642                 }
 643                 if ( strval( $row->Seconds_Behind_Master ) === '' ) {
 644                         return false;
 645                 } else {
 646                         return intval( $row->Seconds_Behind_Master );
 647                 }
 648         }
 649
 650         /**
 651          * Wait for the slave to catch up to a given master position.
 652          * @todo Return values for this and base class are rubbish
 653          *
 654          * @param DBMasterPos|MySQLMasterPos $pos
 655          * @param int $timeout The maximum number of seconds to wait for synchronisation
 656          * @return int Zero if the slave was past that position already,
 657          *   greater than zero if we waited for some period of time, less than
 658          *   zero if we timed out.
 659          */
 660         function masterPosWait( DBMasterPos $pos, $timeout ) {
 661                 if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
 662                         return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 663                 }
 664
 665                 # Commit any open transactions
 666                 $this->commit( __METHOD__, 'flush' );
 667
 668                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 669                         $wait = intval( ( $pos->pos - microtime( true ) + $this->mFakeSlaveLag ) * 1e6 );
 670
 671                         if ( $wait > $timeout * 1e6 ) {
 672                                 wfDebug( "Fake slave timed out waiting for $pos ($wait us)\n" );
 673
 674                                 return -1;
 675                         } elseif ( $wait > 0 ) {
 676                                 wfDebug( "Fake slave waiting $wait us\n" );
 677                                 usleep( $wait );
 678
 679                                 return 1;
 680                         } else {
 681                                 wfDebug( "Fake slave up to date ($wait us)\n" );
 682
 683                                 return 0;
 684                         }
 685                 }
 686
 687                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 688                 $encFile = $this->addQuotes( $pos->file );
 689                 $encPos = intval( $pos->pos );
 690                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 691                 $res = $this->doQuery( $sql );
 692
 693                 $status = false;
 694                 if ( $res && $row = $this->fetchRow( $res ) ) {
 695                         $status = $row[0]; // can be NULL, -1, or 0+ per the MySQL manual
 696                         if ( ctype_digit( $status ) ) { // success
 697                                 $this->lastKnownSlavePos = $pos;
 698                         }
 699                 }
 700
 701
 702                 return $status;
 703         }
 704
 705         /**
 706          * Get the position of the master from SHOW SLAVE STATUS
 707          *
 708          * @return MySQLMasterPos|bool
 709          */
 710         function getSlavePos() {
 711                 if ( !is_null( $this->mFakeSlaveLag ) ) {
 712                         $pos = new MySQLMasterPos( 'fake', microtime( true ) - $this->mFakeSlaveLag );
 713                         wfDebug( __METHOD__ . ": fake slave pos = $pos\n" );
 714
 715                         return $pos;
 716                 }
 717
 718                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
 719                 $row = $this->fetchObject( $res );
 720
 721                 if ( $row ) {
 722                         $pos = isset( $row->Exec_master_log_pos )
 723                                 ? $row->Exec_master_log_pos
 724                                 : $row->Exec_Master_Log_Pos;
 725
 726                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
 727                 } else {
 728                         return false;
 729                 }
 730         }
 731
 732         /**
 733          * Get the position of the master from SHOW MASTER STATUS
 734          *
 735          * @return MySQLMasterPos|bool
 736          */
 737         function getMasterPos() {
 738                 if ( $this->mFakeMaster ) {
 739                         return new MySQLMasterPos( 'fake', microtime( true ) );
 740                 }
 741
 742                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
 743                 $row = $this->fetchObject( $res );
 744
 745                 if ( $row ) {
 746                         return new MySQLMasterPos( $row->File, $row->Position );
 747                 } else {
 748                         return false;
 749                 }
 750         }
 751
 752         /**
 753          * @param string $index
 754          * @return string
 755          */
 756         function useIndexClause( $index ) {
 757                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 758         }
 759
 760         /**
 761          * @return string
 762          */
 763         function lowPriorityOption() {
 764                 return 'LOW_PRIORITY';
 765         }
 766
 767         /**
 768          * @return string
 769          */
 770         public function getSoftwareLink() {
 771                 // MariaDB includes its name in its version string; this is how MariaDB's version of
 772                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
 773                 // in libmysql/libmysql.c).
 774                 $version = $this->getServerVersion();
 775                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 776                         return '[{{int:version-db-mariadb-url}} MariaDB]';
 777                 }
 778
 779                 // Percona Server's version suffix is not very distinctive, and @@version_comment
 780                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
 781                 // (Even Percona's version of mysql doesn't try to make the distinction.)
 782                 return '[{{int:version-db-mysql-url}} MySQL]';
 783         }
 784
 785         /**
 786          * @return string
 787          */
 788         public function getServerVersion() {
 789                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
 790                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
 791                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
 792                 if ( $this->serverVersion === null ) {
 793                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
 794                 }
 795                 return $this->serverVersion;
 796         }
 797
 798         /**
 799          * @param array $options
 800          */
 801         public function setSessionOptions( array $options ) {
 802                 if ( isset( $options['connTimeout'] ) ) {
 803                         $timeout = (int)$options['connTimeout'];
 804                         $this->query( "SET net_read_timeout=$timeout" );
 805                         $this->query( "SET net_write_timeout=$timeout" );
 806                 }
 807         }
 808
 809         /**
 810          * @param string $sql
 811          * @param string $newLine
 812          * @return bool
 813          */
 814         public function streamStatementEnd( &$sql, &$newLine ) {
 815                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 816                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 817                         $this->delimiter = $m[1];
 818                         $newLine = '';
 819                 }
 820
 821                 return parent::streamStatementEnd( $sql, $newLine );
 822         }
 823
 824         /**
 825          * Check to see if a named lock is available. This is non-blocking.
 826          *
 827          * @param string $lockName Name of lock to poll
 828          * @param string $method Name of method calling us
 829          * @return bool
 830          * @since 1.20
 831          */
 832         public function lockIsFree( $lockName, $method ) {
 833                 $lockName = $this->addQuotes( $lockName );
 834                 $result = $this->query( "SELECT IS_FREE_LOCK($lockName) AS lockstatus", $method );
 835                 $row = $this->fetchObject( $result );
 836
 837                 return ( $row->lockstatus == 1 );
 838         }
 839
 840         /**
 841          * @param string $lockName
 842          * @param string $method
 843          * @param int $timeout
 844          * @return bool
 845          */
 846         public function lock( $lockName, $method, $timeout = 5 ) {
 847                 $lockName = $this->addQuotes( $lockName );
 848                 $result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
 849                 $row = $this->fetchObject( $result );
 850
 851                 if ( $row->lockstatus == 1 ) {
 852                         return true;
 853                 } else {
 854                         wfDebug( __METHOD__ . " failed to acquire lock\n" );
 855
 856                         return false;
 857                 }
 858         }
 859
 860         /**
 861          * FROM MYSQL DOCS:
 862          * http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
 863          * @param string $lockName
 864          * @param string $method
 865          * @return bool
 866          */
 867         public function unlock( $lockName, $method ) {
 868                 $lockName = $this->addQuotes( $lockName );
 869                 $result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
 870                 $row = $this->fetchObject( $result );
 871
 872                 return ( $row->lockstatus == 1 );
 873         }
 874
 875         /**
 876          * @param array $read
 877          * @param array $write
 878          * @param string $method
 879          * @param bool $lowPriority
 880          * @return bool
 881          */
 882         public function lockTables( $read, $write, $method, $lowPriority = true ) {
 883                 $items = array();
 884
 885                 foreach ( $write as $table ) {
 886                         $tbl = $this->tableName( $table ) .
 887                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
 888                                 ' WRITE';
 889                         $items[] = $tbl;
 890                 }
 891                 foreach ( $read as $table ) {
 892                         $items[] = $this->tableName( $table ) . ' READ';
 893                 }
 894                 $sql = "LOCK TABLES " . implode( ',', $items );
 895                 $this->query( $sql, $method );
 896
 897                 return true;
 898         }
 899
 900         /**
 901          * @param string $method
 902          * @return bool
 903          */
 904         public function unlockTables( $method ) {
 905                 $this->query( "UNLOCK TABLES", $method );
 906
 907                 return true;
 908         }
 909
 910         /**
 911          * Get search engine class. All subclasses of this
 912          * need to implement this if they wish to use searching.
 913          *
 914          * @return string
 915          */
 916         public function getSearchEngine() {
 917                 return 'SearchMySQL';
 918         }
 919
 920         /**
 921          * @param bool $value
 922          */
 923         public function setBigSelects( $value = true ) {
 924                 if ( $value === 'default' ) {
 925                         if ( $this->mDefaultBigSelects === null ) {
 926                                 # Function hasn't been called before so it must already be set to the default
 927                                 return;
 928                         } else {
 929                                 $value = $this->mDefaultBigSelects;
 930                         }
 931                 } elseif ( $this->mDefaultBigSelects === null ) {
 932                         $this->mDefaultBigSelects = (bool)$this->selectField( false, '@@sql_big_selects' );
 933                 }
 934                 $encValue = $value ? '1' : '0';
 935                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
 936         }
 937
 938         /**
 939          * DELETE where the condition is a join. MySql uses multi-table deletes.
 940          * @param string $delTable
 941          * @param string $joinTable
 942          * @param string $delVar
 943          * @param string $joinVar
 944          * @param array|string $conds
 945          * @param bool|string $fname
 946          * @throws DBUnexpectedError
 947          * @return bool|ResultWrapper
 948          */
 949         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) {
 950                 if ( !$conds ) {
 951                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
 952                 }
 953
 954                 $delTable = $this->tableName( $delTable );
 955                 $joinTable = $this->tableName( $joinTable );
 956                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
 957
 958                 if ( $conds != '*' ) {
 959                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
 960                 }
 961
 962                 return $this->query( $sql, $fname );
 963         }
 964
 965         /**
 966          * @param string $table
 967          * @param array $rows
 968          * @param array $uniqueIndexes
 969          * @param array $set
 970          * @param string $fname
 971          * @return bool
 972          */
 973         public function upsert( $table, array $rows, array $uniqueIndexes,
 974                 array $set, $fname = __METHOD__
 975         ) {
 976                 if ( !count( $rows ) ) {
 977                         return true; // nothing to do
 978                 }
 979
 980                 if ( !is_array( reset( $rows ) ) ) {
 981                         $rows = array( $rows );
 982                 }
 983
 984                 $table = $this->tableName( $table );
 985                 $columns = array_keys( $rows[0] );
 986
 987                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
 988                 $rowTuples = array();
 989                 foreach ( $rows as $row ) {
 990                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
 991                 }
 992                 $sql .= implode( ',', $rowTuples );
 993                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, LIST_SET );
 994
 995                 return (bool)$this->query( $sql, $fname );
 996         }
 997
 998         /**
 999          * Determines how long the server has been up
1000          *
1001          * @return int
1002          */
1003         function getServerUptime() {
1004                 $vars = $this->getMysqlStatus( 'Uptime' );
1005
1006                 return (int)$vars['Uptime'];
1007         }
1008
1009         /**
1010          * Determines if the last failure was due to a deadlock
1011          *
1012          * @return bool
1013          */
1014         function wasDeadlock() {
1015                 return $this->lastErrno() == 1213;
1016         }
1017
1018         /**
1019          * Determines if the last failure was due to a lock timeout
1020          *
1021          * @return bool
1022          */
1023         function wasLockTimeout() {
1024                 return $this->lastErrno() == 1205;
1025         }
1026
1027         /**
1028          * Determines if the last query error was something that should be dealt
1029          * with by pinging the connection and reissuing the query
1030          *
1031          * @return bool
1032          */
1033         function wasErrorReissuable() {
1034                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
1035         }
1036
1037         /**
1038          * Determines if the last failure was due to the database being read-only.
1039          *
1040          * @return bool
1041          */
1042         function wasReadOnlyError() {
1043                 return $this->lastErrno() == 1223 ||
1044                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1045         }
1046
1047         /**
1048          * @param string $oldName
1049          * @param string $newName
1050          * @param bool $temporary
1051          * @param string $fname
1052          * @return bool
1053          */
1054         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1055                 $tmp = $temporary ? 'TEMPORARY ' : '';
1056                 $newName = $this->addIdentifierQuotes( $newName );
1057                 $oldName = $this->addIdentifierQuotes( $oldName );
1058                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1059
1060                 return $this->query( $query, $fname );
1061         }
1062
1063         /**
1064          * List all tables on the database
1065          *
1066          * @param string $prefix Only show tables with this prefix, e.g. mw_
1067          * @param string $fname Calling function name
1068          * @return array
1069          */
1070         function listTables( $prefix = null, $fname = __METHOD__ ) {
1071                 $result = $this->query( "SHOW TABLES", $fname );
1072
1073                 $endArray = array();
1074
1075                 foreach ( $result as $table ) {
1076                         $vars = get_object_vars( $table );
1077                         $table = array_pop( $vars );
1078
1079                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1080                                 $endArray[] = $table;
1081                         }
1082                 }
1083
1084                 return $endArray;
1085         }
1086
1087         /**
1088          * @param string $tableName
1089          * @param string $fName
1090          * @return bool|ResultWrapper
1091          */
1092         public function dropTable( $tableName, $fName = __METHOD__ ) {
1093                 if ( !$this->tableExists( $tableName, $fName ) ) {
1094                         return false;
1095                 }
1096
1097                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1098         }
1099
1100         /**
1101          * @return array
1102          */
1103         protected function getDefaultSchemaVars() {
1104                 $vars = parent::getDefaultSchemaVars();
1105                 $vars['wgDBTableOptions'] = str_replace( 'TYPE', 'ENGINE', $GLOBALS['wgDBTableOptions'] );
1106                 $vars['wgDBTableOptions'] = str_replace(
1107                         'CHARSET=mysql4',
1108                         'CHARSET=binary',
1109                         $vars['wgDBTableOptions']
1110                 );
1111
1112                 return $vars;
1113         }
1114
1115         /**
1116          * Get status information from SHOW STATUS in an associative array
1117          *
1118          * @param string $which
1119          * @return array
1120          */
1121         function getMysqlStatus( $which = "%" ) {
1122                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1123                 $status = array();
1124
1125                 foreach ( $res as $row ) {
1126                         $status[$row->Variable_name] = $row->Value;
1127                 }
1128
1129                 return $status;
1130         }
1131
1132         /**
1133          * Lists VIEWs in the database
1134          *
1135          * @param string $prefix Only show VIEWs with this prefix, eg.
1136          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1137          * @param string $fname Name of calling function
1138          * @return array
1139          * @since 1.22
1140          */
1141         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1142
1143                 if ( !isset( $this->allViews ) ) {
1144
1145                         // The name of the column containing the name of the VIEW
1146                         $propertyName = 'Tables_in_' . $this->mDBname;
1147
1148                         // Query for the VIEWS
1149                         $result = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1150                         $this->allViews = array();
1151                         while ( ( $row = $this->fetchRow( $result ) ) !== false ) {
1152                                 array_push( $this->allViews, $row[$propertyName] );
1153                         }
1154                 }
1155
1156                 if ( is_null( $prefix ) || $prefix === '' ) {
1157                         return $this->allViews;
1158                 }
1159
1160                 $filteredViews = array();
1161                 foreach ( $this->allViews as $viewName ) {
1162                         // Does the name of this VIEW start with the table-prefix?
1163                         if ( strpos( $viewName, $prefix ) === 0 ) {
1164                                 array_push( $filteredViews, $viewName );
1165                         }
1166                 }
1167
1168                 return $filteredViews;
1169         }
1170
1171         /**
1172          * Differentiates between a TABLE and a VIEW.
1173          *
1174          * @param string $name Name of the TABLE/VIEW to test
1175          * @param string $prefix
1176          * @return bool
1177          * @since 1.22
1178          */
1179         public function isView( $name, $prefix = null ) {
1180                 return in_array( $name, $this->listViews( $prefix ) );
1181         }
1182 }
1183
1184 /**
1185  * Utility class.
1186  * @ingroup Database
1187  */
1188 class MySQLField implements Field {
1189         private $name, $tablename, $default, $max_length, $nullable,
1190                 $is_pk, $is_unique, $is_multiple, $is_key, $type, $binary;
1191
1192         function __construct( $info ) {
1193                 $this->name = $info->name;
1194                 $this->tablename = $info->table;
1195                 $this->default = $info->def;
1196                 $this->max_length = $info->max_length;
1197                 $this->nullable = !$info->not_null;
1198                 $this->is_pk = $info->primary_key;
1199                 $this->is_unique = $info->unique_key;
1200                 $this->is_multiple = $info->multiple_key;
1201                 $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
1202                 $this->type = $info->type;
1203                 $this->binary = isset( $info->binary ) ? $info->binary : false;
1204         }
1205
1206         /**
1207          * @return string
1208          */
1209         function name() {
1210                 return $this->name;
1211         }
1212
1213         /**
1214          * @return string
1215          */
1216         function tableName() {
1217                 return $this->tableName;
1218         }
1219
1220         /**
1221          * @return string
1222          */
1223         function type() {
1224                 return $this->type;
1225         }
1226
1227         /**
1228          * @return bool
1229          */
1230         function isNullable() {
1231                 return $this->nullable;
1232         }
1233
1234         function defaultValue() {
1235                 return $this->default;
1236         }
1237
1238         /**
1239          * @return bool
1240          */
1241         function isKey() {
1242                 return $this->is_key;
1243         }
1244
1245         /**
1246          * @return bool
1247          */
1248         function isMultipleKey() {
1249                 return $this->is_multiple;
1250         }
1251
1252         function isBinary() {
1253                 return $this->binary;
1254         }
1255 }
1256
1257 class MySQLMasterPos implements DBMasterPos {
1258         /** @var string */
1259         public $file;
1260         /** @var int Position */
1261         public $pos;
1262         /** @var float UNIX timestamp */
1263         public $asOfTime = 0.0;
1264
1265         function __construct( $file, $pos ) {
1266                 $this->file = $file;
1267                 $this->pos = $pos;
1268                 $this->asOfTime = microtime( true );
1269         }
1270
1271         function __toString() {
1272                 // e.g db1034-bin.000976/843431247
1273                 return "{$this->file}/{$this->pos}";
1274         }
1275
1276         /**
1277          * @return array|bool (int, int)
1278          */
1279         protected function getCoordinates() {
1280                 $m = array();
1281                 if ( preg_match( '!\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
1282                         return array( (int)$m[1], (int)$m[2] );
1283                 }
1284
1285                 return false;
1286         }
1287
1288         function hasReached( MySQLMasterPos $pos ) {
1289                 $thisPos = $this->getCoordinates();
1290                 $thatPos = $pos->getCoordinates();
1291
1292                 return ( $thisPos && $thatPos && $thisPos >= $thatPos );
1293         }
1294
1295         function asOfTime() {
1296                 return $this->asOfTime;
1297         }
1298 }