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 Database {
  33         /** @var MysqlMasterPos */
  34         protected $lastKnownSlavePos;
  35         /** @var string Method to detect slave lag */
  36         protected $lagDetectionMethod;
  37
  38         /** @var string|null */
  39         private $serverVersion = null;
  40
  41         /**
  42          * Additional $params include:
  43          *   - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat).
  44          *                          pt-heartbeat assumes the table is at heartbeat.heartbeat
  45          *                          and uses UTC timestamps in the heartbeat.ts column.
  46          *                          (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html)
  47          * @param array $params
  48          */
  49         function __construct( array $params ) {
  50                 parent::__construct( $params );
  51
  52                 $this->lagDetectionMethod = isset( $params['lagDetectionMethod'] )
  53                         ? $params['lagDetectionMethod']
  54                         : 'Seconds_Behind_Master';
  55         }
  56
  57         /**
  58          * @return string
  59          */
  60         function getType() {
  61                 return 'mysql';
  62         }
  63
  64         /**
  65          * @param string $server
  66          * @param string $user
  67          * @param string $password
  68          * @param string $dbName
  69          * @throws Exception|DBConnectionError
  70          * @return bool
  71          */
  72         function open( $server, $user, $password, $dbName ) {
  73                 global $wgAllDBsAreLocalhost, $wgSQLMode;
  74
  75                 # Close/unset connection handle
  76                 $this->close();
  77
  78                 # Debugging hack -- fake cluster
  79                 $realServer = $wgAllDBsAreLocalhost ? 'localhost' : $server;
  80                 $this->mServer = $server;
  81                 $this->mUser = $user;
  82                 $this->mPassword = $password;
  83                 $this->mDBname = $dbName;
  84
  85                 $this->installErrorHandler();
  86                 try {
  87                         $this->mConn = $this->mysqlConnect( $realServer );
  88                 } catch ( Exception $ex ) {
  89                         $this->restoreErrorHandler();
  90                         throw $ex;
  91                 }
  92                 $error = $this->restoreErrorHandler();
  93
  94                 # Always log connection errors
  95                 if ( !$this->mConn ) {
  96                         if ( !$error ) {
  97                                 $error = $this->lastError();
  98                         }
  99                         wfLogDBError(
 100                                 "Error connecting to {db_server}: {error}",
 101                                 $this->getLogContext( array(
 102                                         'method' => __METHOD__,
 103                                         'error' => $error,
 104                                 ) )
 105                         );
 106                         wfDebug( "DB connection error\n" .
 107                                 "Server: $server, User: $user, Password: " .
 108                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 109
 110                         $this->reportConnectionError( $error );
 111                 }
 112
 113                 if ( $dbName != '' ) {
 114                         MediaWiki\suppressWarnings();
 115                         $success = $this->selectDB( $dbName );
 116                         MediaWiki\restoreWarnings();
 117                         if ( !$success ) {
 118                                 wfLogDBError(
 119                                         "Error selecting database {db_name} on server {db_server}",
 120                                         $this->getLogContext( array(
 121                                                 'method' => __METHOD__,
 122                                         ) )
 123                                 );
 124                                 wfDebug( "Error selecting database $dbName on server {$this->mServer} " .
 125                                         "from client host " . wfHostname() . "\n" );
 126
 127                                 $this->reportConnectionError( "Error selecting database $dbName" );
 128                         }
 129                 }
 130
 131                 // Tell the server what we're communicating with
 132                 if ( !$this->connectInitCharset() ) {
 133                         $this->reportConnectionError( "Error setting character set" );
 134                 }
 135
 136                 // Abstract over any insane MySQL defaults
 137                 $set = array( 'group_concat_max_len = 262144' );
 138                 // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 139                 if ( is_string( $wgSQLMode ) ) {
 140                         $set[] = 'sql_mode = ' . $this->addQuotes( $wgSQLMode );
 141                 }
 142                 // Set any custom settings defined by site config
 143                 // (e.g. https://dev.mysql.com/doc/refman/4.1/en/innodb-parameters.html)
 144                 foreach ( $this->mSessionVars as $var => $val ) {
 145                         // Escape strings but not numbers to avoid MySQL complaining
 146                         if ( !is_int( $val ) && !is_float( $val ) ) {
 147                                 $val = $this->addQuotes( $val );
 148                         }
 149                         $set[] = $this->addIdentifierQuotes( $var ) . ' = ' . $val;
 150                 }
 151
 152                 if ( $set ) {
 153                         // Use doQuery() to avoid opening implicit transactions (DBO_TRX)
 154                         $success = $this->doQuery( 'SET ' . implode( ', ', $set ) );
 155                         if ( !$success ) {
 156                                 wfLogDBError(
 157                                         'Error setting MySQL variables on server {db_server} (check $wgSQLMode)',
 158                                         $this->getLogContext( array(
 159                                                 'method' => __METHOD__,
 160                                         ) )
 161                                 );
 162                                 $this->reportConnectionError(
 163                                         'Error setting MySQL variables on server {db_server} (check $wgSQLMode)' );
 164                         }
 165                 }
 166
 167                 $this->mOpened = true;
 168
 169                 return true;
 170         }
 171
 172         /**
 173          * Set the character set information right after connection
 174          * @return bool
 175          */
 176         protected function connectInitCharset() {
 177                 global $wgDBmysql5;
 178
 179                 if ( $wgDBmysql5 ) {
 180                         // Tell the server we're communicating with it in UTF-8.
 181                         // This may engage various charset conversions.
 182                         return $this->mysqlSetCharset( 'utf8' );
 183                 } else {
 184                         return $this->mysqlSetCharset( 'binary' );
 185                 }
 186         }
 187
 188         /**
 189          * Open a connection to a MySQL server
 190          *
 191          * @param string $realServer
 192          * @return mixed Raw connection
 193          * @throws DBConnectionError
 194          */
 195         abstract protected function mysqlConnect( $realServer );
 196
 197         /**
 198          * Set the character set of the MySQL link
 199          *
 200          * @param string $charset
 201          * @return bool
 202          */
 203         abstract protected function mysqlSetCharset( $charset );
 204
 205         /**
 206          * @param ResultWrapper|resource $res
 207          * @throws DBUnexpectedError
 208          */
 209         function freeResult( $res ) {
 210                 if ( $res instanceof ResultWrapper ) {
 211                         $res = $res->result;
 212                 }
 213                 MediaWiki\suppressWarnings();
 214                 $ok = $this->mysqlFreeResult( $res );
 215                 MediaWiki\restoreWarnings();
 216                 if ( !$ok ) {
 217                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 218                 }
 219         }
 220
 221         /**
 222          * Free result memory
 223          *
 224          * @param resource $res Raw result
 225          * @return bool
 226          */
 227         abstract protected function mysqlFreeResult( $res );
 228
 229         /**
 230          * @param ResultWrapper|resource $res
 231          * @return stdClass|bool
 232          * @throws DBUnexpectedError
 233          */
 234         function fetchObject( $res ) {
 235                 if ( $res instanceof ResultWrapper ) {
 236                         $res = $res->result;
 237                 }
 238                 MediaWiki\suppressWarnings();
 239                 $row = $this->mysqlFetchObject( $res );
 240                 MediaWiki\restoreWarnings();
 241
 242                 $errno = $this->lastErrno();
 243                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 244                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 245                 // these are the only errors mysql_fetch_object can cause.
 246                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 247                 if ( $errno == 2000 || $errno == 2013 ) {
 248                         throw new DBUnexpectedError(
 249                                 $this,
 250                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 251                         );
 252                 }
 253
 254                 return $row;
 255         }
 256
 257         /**
 258          * Fetch a result row as an object
 259          *
 260          * @param resource $res Raw result
 261          * @return stdClass
 262          */
 263         abstract protected function mysqlFetchObject( $res );
 264
 265         /**
 266          * @param ResultWrapper|resource $res
 267          * @return array|bool
 268          * @throws DBUnexpectedError
 269          */
 270         function fetchRow( $res ) {
 271                 if ( $res instanceof ResultWrapper ) {
 272                         $res = $res->result;
 273                 }
 274                 MediaWiki\suppressWarnings();
 275                 $row = $this->mysqlFetchArray( $res );
 276                 MediaWiki\restoreWarnings();
 277
 278                 $errno = $this->lastErrno();
 279                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 280                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 281                 // these are the only errors mysql_fetch_array can cause.
 282                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 283                 if ( $errno == 2000 || $errno == 2013 ) {
 284                         throw new DBUnexpectedError(
 285                                 $this,
 286                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 287                         );
 288                 }
 289
 290                 return $row;
 291         }
 292
 293         /**
 294          * Fetch a result row as an associative and numeric array
 295          *
 296          * @param resource $res Raw result
 297          * @return array
 298          */
 299         abstract protected function mysqlFetchArray( $res );
 300
 301         /**
 302          * @throws DBUnexpectedError
 303          * @param ResultWrapper|resource $res
 304          * @return int
 305          */
 306         function numRows( $res ) {
 307                 if ( $res instanceof ResultWrapper ) {
 308                         $res = $res->result;
 309                 }
 310                 MediaWiki\suppressWarnings();
 311                 $n = $this->mysqlNumRows( $res );
 312                 MediaWiki\restoreWarnings();
 313
 314                 // Unfortunately, mysql_num_rows does not reset the last errno.
 315                 // We are not checking for any errors here, since
 316                 // these are no errors mysql_num_rows can cause.
 317                 // See http://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 318                 // See https://phabricator.wikimedia.org/T44430
 319                 return $n;
 320         }
 321
 322         /**
 323          * Get number of rows in result
 324          *
 325          * @param resource $res Raw result
 326          * @return int
 327          */
 328         abstract protected function mysqlNumRows( $res );
 329
 330         /**
 331          * @param ResultWrapper|resource $res
 332          * @return int
 333          */
 334         function numFields( $res ) {
 335                 if ( $res instanceof ResultWrapper ) {
 336                         $res = $res->result;
 337                 }
 338
 339                 return $this->mysqlNumFields( $res );
 340         }
 341
 342         /**
 343          * Get number of fields in result
 344          *
 345          * @param resource $res Raw result
 346          * @return int
 347          */
 348         abstract protected function mysqlNumFields( $res );
 349
 350         /**
 351          * @param ResultWrapper|resource $res
 352          * @param int $n
 353          * @return string
 354          */
 355         function fieldName( $res, $n ) {
 356                 if ( $res instanceof ResultWrapper ) {
 357                         $res = $res->result;
 358                 }
 359
 360                 return $this->mysqlFieldName( $res, $n );
 361         }
 362
 363         /**
 364          * Get the name of the specified field in a result
 365          *
 366          * @param ResultWrapper|resource $res
 367          * @param int $n
 368          * @return string
 369          */
 370         abstract protected function mysqlFieldName( $res, $n );
 371
 372         /**
 373          * mysql_field_type() wrapper
 374          * @param ResultWrapper|resource $res
 375          * @param int $n
 376          * @return string
 377          */
 378         public function fieldType( $res, $n ) {
 379                 if ( $res instanceof ResultWrapper ) {
 380                         $res = $res->result;
 381                 }
 382
 383                 return $this->mysqlFieldType( $res, $n );
 384         }
 385
 386         /**
 387          * Get the type of the specified field in a result
 388          *
 389          * @param ResultWrapper|resource $res
 390          * @param int $n
 391          * @return string
 392          */
 393         abstract protected function mysqlFieldType( $res, $n );
 394
 395         /**
 396          * @param ResultWrapper|resource $res
 397          * @param int $row
 398          * @return bool
 399          */
 400         function dataSeek( $res, $row ) {
 401                 if ( $res instanceof ResultWrapper ) {
 402                         $res = $res->result;
 403                 }
 404
 405                 return $this->mysqlDataSeek( $res, $row );
 406         }
 407
 408         /**
 409          * Move internal result pointer
 410          *
 411          * @param ResultWrapper|resource $res
 412          * @param int $row
 413          * @return bool
 414          */
 415         abstract protected function mysqlDataSeek( $res, $row );
 416
 417         /**
 418          * @return string
 419          */
 420         function lastError() {
 421                 if ( $this->mConn ) {
 422                         # Even if it's non-zero, it can still be invalid
 423                         MediaWiki\suppressWarnings();
 424                         $error = $this->mysqlError( $this->mConn );
 425                         if ( !$error ) {
 426                                 $error = $this->mysqlError();
 427                         }
 428                         MediaWiki\restoreWarnings();
 429                 } else {
 430                         $error = $this->mysqlError();
 431                 }
 432                 if ( $error ) {
 433                         $error .= ' (' . $this->mServer . ')';
 434                 }
 435
 436                 return $error;
 437         }
 438
 439         /**
 440          * Returns the text of the error message from previous MySQL operation
 441          *
 442          * @param resource $conn Raw connection
 443          * @return string
 444          */
 445         abstract protected function mysqlError( $conn = null );
 446
 447         /**
 448          * @param string $table
 449          * @param array $uniqueIndexes
 450          * @param array $rows
 451          * @param string $fname
 452          * @return ResultWrapper
 453          */
 454         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 455                 return $this->nativeReplace( $table, $rows, $fname );
 456         }
 457
 458         /**
 459          * Estimate rows in dataset
 460          * Returns estimated count, based on EXPLAIN output
 461          * Takes same arguments as Database::select()
 462          *
 463          * @param string|array $table
 464          * @param string|array $vars
 465          * @param string|array $conds
 466          * @param string $fname
 467          * @param string|array $options
 468          * @return bool|int
 469          */
 470         public function estimateRowCount( $table, $vars = '*', $conds = '',
 471                 $fname = __METHOD__, $options = array()
 472         ) {
 473                 $options['EXPLAIN'] = true;
 474                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 475                 if ( $res === false ) {
 476                         return false;
 477                 }
 478                 if ( !$this->numRows( $res ) ) {
 479                         return 0;
 480                 }
 481
 482                 $rows = 1;
 483                 foreach ( $res as $plan ) {
 484                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 485                 }
 486
 487                 return (int)$rows;
 488         }
 489
 490         /**
 491          * @param string $table
 492          * @param string $field
 493          * @return bool|MySQLField
 494          */
 495         function fieldInfo( $table, $field ) {
 496                 $table = $this->tableName( $table );
 497                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 498                 if ( !$res ) {
 499                         return false;
 500                 }
 501                 $n = $this->mysqlNumFields( $res->result );
 502                 for ( $i = 0; $i < $n; $i++ ) {
 503                         $meta = $this->mysqlFetchField( $res->result, $i );
 504                         if ( $field == $meta->name ) {
 505                                 return new MySQLField( $meta );
 506                         }
 507                 }
 508
 509                 return false;
 510         }
 511
 512         /**
 513          * Get column information from a result
 514          *
 515          * @param resource $res Raw result
 516          * @param int $n
 517          * @return stdClass
 518          */
 519         abstract protected function mysqlFetchField( $res, $n );
 520
 521         /**
 522          * Get information about an index into an object
 523          * Returns false if the index does not exist
 524          *
 525          * @param string $table
 526          * @param string $index
 527          * @param string $fname
 528          * @return bool|array|null False or null on failure
 529          */
 530         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 531                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 532                 # SHOW INDEX should work for 3.x and up:
 533                 # http://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 534                 $table = $this->tableName( $table );
 535                 $index = $this->indexName( $index );
 536
 537                 $sql = 'SHOW INDEX FROM ' . $table;
 538                 $res = $this->query( $sql, $fname );
 539
 540                 if ( !$res ) {
 541                         return null;
 542                 }
 543
 544                 $result = array();
 545
 546                 foreach ( $res as $row ) {
 547                         if ( $row->Key_name == $index ) {
 548                                 $result[] = $row;
 549                         }
 550                 }
 551
 552                 return empty( $result ) ? false : $result;
 553         }
 554
 555         /**
 556          * @param string $s
 557          * @return string
 558          */
 559         function strencode( $s ) {
 560                 $sQuoted = $this->mysqlRealEscapeString( $s );
 561
 562                 if ( $sQuoted === false ) {
 563                         $this->ping();
 564                         $sQuoted = $this->mysqlRealEscapeString( $s );
 565                 }
 566
 567                 return $sQuoted;
 568         }
 569
 570         /**
 571          * @param string $s
 572          * @return mixed
 573          */
 574         abstract protected function mysqlRealEscapeString( $s );
 575
 576         /**
 577          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 578          *
 579          * @param string $s
 580          * @return string
 581          */
 582         public function addIdentifierQuotes( $s ) {
 583                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 584                 // Remove NUL bytes and escape backticks by doubling
 585                 return '`' . str_replace( array( "\0", '`' ), array( '', '``' ), $s ) . '`';
 586         }
 587
 588         /**
 589          * @param string $name
 590          * @return bool
 591          */
 592         public function isQuotedIdentifier( $name ) {
 593                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 594         }
 595
 596         /**
 597          * @return bool
 598          */
 599         function ping() {
 600                 $ping = $this->mysqlPing();
 601                 if ( $ping ) {
 602                         // Connection was good or lost but reconnected...
 603                         // @note: mysqlnd (php 5.6+) does not support this (PHP bug 52561)
 604                         return true;
 605                 }
 606
 607                 // Try a full disconnect/reconnect cycle if ping() failed
 608                 $this->closeConnection();
 609                 $this->mOpened = false;
 610                 $this->mConn = false;
 611                 $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
 612
 613                 return true;
 614         }
 615
 616         /**
 617          * Ping a server connection or reconnect if there is no connection
 618          *
 619          * @return bool
 620          */
 621         abstract protected function mysqlPing();
 622
 623         function getLag() {
 624                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 625                         return $this->getLagFromPtHeartbeat();
 626                 } else {
 627                         return $this->getLagFromSlaveStatus();
 628                 }
 629         }
 630
 631         /**
 632          * @return string
 633          */
 634         protected function getLagDetectionMethod() {
 635                 return $this->lagDetectionMethod;
 636         }
 637
 638         /**
 639          * @return bool|int
 640          */
 641         protected function getLagFromSlaveStatus() {
 642                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 643                 $row = $res ? $res->fetchObject() : false;
 644                 if ( $row && strval( $row->Seconds_Behind_Master ) !== '' ) {
 645                         return intval( $row->Seconds_Behind_Master );
 646                 }
 647
 648                 return false;
 649         }
 650
 651         /**
 652          * @return bool|float
 653          */
 654         protected function getLagFromPtHeartbeat() {
 655                 $masterInfo = $this->getMasterServerInfo();
 656                 if ( !$masterInfo ) {
 657                         return false; // could not get master server ID
 658                 }
 659
 660                 list( $time, $nowUnix ) = $this->getHeartbeatData( $masterInfo['serverId'] );
 661                 if ( $time !== null ) {
 662                         // @time is in ISO format like "2015-09-25T16:48:10.000510"
 663                         $dateTime = new DateTime( $time, new DateTimeZone( 'UTC' ) );
 664                         $timeUnix = (int)$dateTime->format( 'U' ) + $dateTime->format( 'u' ) / 1e6;
 665
 666                         return max( $nowUnix - $timeUnix, 0.0 );
 667                 }
 668
 669                 return false;
 670         }
 671
 672         protected function getMasterServerInfo() {
 673                 $cache = $this->srvCache;
 674                 $key = $cache->makeGlobalKey(
 675                         'mysql',
 676                         'master-info',
 677                         // Using one key for all cluster slaves is preferable
 678                         $this->getLBInfo( 'clusterMasterHost' ) ?: $this->getServer()
 679                 );
 680
 681                 $that = $this;
 682                 return $cache->getWithSetCallback(
 683                         $key,
 684                         $cache::TTL_INDEFINITE,
 685                         function () use ( $that, $cache, $key ) {
 686                                 // Get and leave a lock key in place for a short period
 687                                 if ( !$cache->lock( $key, 0, 10 ) ) {
 688                                         return false; // avoid master connection spike slams
 689                                 }
 690
 691                                 $conn = $that->getLazyMasterHandle();
 692                                 if ( !$conn ) {
 693                                         return false; // something is misconfigured
 694                                 }
 695
 696                                 // Connect to and query the master; catch errors to avoid outages
 697                                 try {
 698                                         $res = $conn->query( 'SELECT @@server_id AS id', __METHOD__ );
 699                                         $row = $res ? $res->fetchObject() : false;
 700                                         $id = $row ? (int)$row->id : 0;
 701                                 } catch ( DBError $e ) {
 702                                         $id = 0;
 703                                 }
 704
 705                                 // Cache the ID if it was retrieved
 706                                 return $id ? array( 'serverId' => $id, 'asOf' => time() ) : false;
 707                         }
 708                 );
 709         }
 710
 711         /**
 712          * @param string $masterId Server ID
 713          * @return array (heartbeat `ts` column value or null, UNIX timestamp)
 714          * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html
 715          */
 716         protected function getHeartbeatData( $masterId ) {
 717                 // Get the status row for this master; use the oldest for sanity in case the master
 718                 // has entries listed under different server IDs (which should really not happen).
 719                 // Note: this would use "MAX(TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6)))" but the
 720                 // percision field is not supported in MySQL <= 5.5.
 721                 $res = $this->query(
 722                         "SELECT ts FROM heartbeat.heartbeat WHERE server_id=" . intval( $masterId )
 723                 );
 724                 $row = $res ? $res->fetchObject() : false;
 725
 726                 return array( $row ? $row->ts : null, microtime( true ) );
 727         }
 728
 729         public function getApproximateLagStatus() {
 730                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 731                         // Disable caching since this is fast enough and we don't wan't
 732                         // to be *too* pessimistic by having both the cache TTL and the
 733                         // pt-heartbeat interval count as lag in getSessionLagStatus()
 734                         return parent::getApproximateLagStatus();
 735                 }
 736
 737                 $key = $this->srvCache->makeGlobalKey( 'mysql-lag', $this->getServer() );
 738                 $approxLag = $this->srvCache->get( $key );
 739                 if ( !$approxLag ) {
 740                         $approxLag = parent::getApproximateLagStatus();
 741                         $this->srvCache->set( $key, $approxLag, 1 );
 742                 }
 743
 744                 return $approxLag;
 745         }
 746
 747         /**
 748          * Wait for the slave to catch up to a given master position.
 749          * @todo Return values for this and base class are rubbish
 750          *
 751          * @param DBMasterPos|MySQLMasterPos $pos
 752          * @param int $timeout The maximum number of seconds to wait for synchronisation
 753          * @return int Zero if the slave was past that position already,
 754          *   greater than zero if we waited for some period of time, less than
 755          *   zero if we timed out.
 756          */
 757         function masterPosWait( DBMasterPos $pos, $timeout ) {
 758                 if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
 759                         return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 760                 }
 761
 762                 # Commit any open transactions
 763                 $this->commit( __METHOD__, 'flush' );
 764
 765                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 766                 $encFile = $this->addQuotes( $pos->file );
 767                 $encPos = intval( $pos->pos );
 768                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 769                 $res = $this->doQuery( $sql );
 770
 771                 $status = false;
 772                 if ( $res ) {
 773                         $row = $this->fetchRow( $res );
 774                         if ( $row ) {
 775                                 $status = $row[0]; // can be NULL, -1, or 0+ per the MySQL manual
 776                                 if ( ctype_digit( $status ) ) { // success
 777                                         $this->lastKnownSlavePos = $pos;
 778                                 }
 779                         }
 780                 }
 781
 782                 return $status;
 783         }
 784
 785         /**
 786          * Get the position of the master from SHOW SLAVE STATUS
 787          *
 788          * @return MySQLMasterPos|bool
 789          */
 790         function getSlavePos() {
 791                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
 792                 $row = $this->fetchObject( $res );
 793
 794                 if ( $row ) {
 795                         $pos = isset( $row->Exec_master_log_pos )
 796                                 ? $row->Exec_master_log_pos
 797                                 : $row->Exec_Master_Log_Pos;
 798
 799                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
 800                 } else {
 801                         return false;
 802                 }
 803         }
 804
 805         /**
 806          * Get the position of the master from SHOW MASTER STATUS
 807          *
 808          * @return MySQLMasterPos|bool
 809          */
 810         function getMasterPos() {
 811                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
 812                 $row = $this->fetchObject( $res );
 813
 814                 if ( $row ) {
 815                         return new MySQLMasterPos( $row->File, $row->Position );
 816                 } else {
 817                         return false;
 818                 }
 819         }
 820
 821         /**
 822          * @param string $index
 823          * @return string
 824          */
 825         function useIndexClause( $index ) {
 826                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 827         }
 828
 829         /**
 830          * @return string
 831          */
 832         function lowPriorityOption() {
 833                 return 'LOW_PRIORITY';
 834         }
 835
 836         /**
 837          * @return string
 838          */
 839         public function getSoftwareLink() {
 840                 // MariaDB includes its name in its version string; this is how MariaDB's version of
 841                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
 842                 // in libmysql/libmysql.c).
 843                 $version = $this->getServerVersion();
 844                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 845                         return '[{{int:version-db-mariadb-url}} MariaDB]';
 846                 }
 847
 848                 // Percona Server's version suffix is not very distinctive, and @@version_comment
 849                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
 850                 // (Even Percona's version of mysql doesn't try to make the distinction.)
 851                 return '[{{int:version-db-mysql-url}} MySQL]';
 852         }
 853
 854         /**
 855          * @return string
 856          */
 857         public function getServerVersion() {
 858                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
 859                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
 860                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
 861                 if ( $this->serverVersion === null ) {
 862                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
 863                 }
 864                 return $this->serverVersion;
 865         }
 866
 867         /**
 868          * @param array $options
 869          */
 870         public function setSessionOptions( array $options ) {
 871                 if ( isset( $options['connTimeout'] ) ) {
 872                         $timeout = (int)$options['connTimeout'];
 873                         $this->query( "SET net_read_timeout=$timeout" );
 874                         $this->query( "SET net_write_timeout=$timeout" );
 875                 }
 876         }
 877
 878         /**
 879          * @param string $sql
 880          * @param string $newLine
 881          * @return bool
 882          */
 883         public function streamStatementEnd( &$sql, &$newLine ) {
 884                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 885                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 886                         $this->delimiter = $m[1];
 887                         $newLine = '';
 888                 }
 889
 890                 return parent::streamStatementEnd( $sql, $newLine );
 891         }
 892
 893         /**
 894          * Check to see if a named lock is available. This is non-blocking.
 895          *
 896          * @param string $lockName Name of lock to poll
 897          * @param string $method Name of method calling us
 898          * @return bool
 899          * @since 1.20
 900          */
 901         public function lockIsFree( $lockName, $method ) {
 902                 $lockName = $this->addQuotes( $lockName );
 903                 $result = $this->query( "SELECT IS_FREE_LOCK($lockName) AS lockstatus", $method );
 904                 $row = $this->fetchObject( $result );
 905
 906                 return ( $row->lockstatus == 1 );
 907         }
 908
 909         /**
 910          * @param string $lockName
 911          * @param string $method
 912          * @param int $timeout
 913          * @return bool
 914          */
 915         public function lock( $lockName, $method, $timeout = 5 ) {
 916                 $lockName = $this->addQuotes( $lockName );
 917                 $result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
 918                 $row = $this->fetchObject( $result );
 919
 920                 if ( $row->lockstatus == 1 ) {
 921                         return true;
 922                 } else {
 923                         wfDebug( __METHOD__ . " failed to acquire lock\n" );
 924
 925                         return false;
 926                 }
 927         }
 928
 929         /**
 930          * FROM MYSQL DOCS:
 931          * http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
 932          * @param string $lockName
 933          * @param string $method
 934          * @return bool
 935          */
 936         public function unlock( $lockName, $method ) {
 937                 $lockName = $this->addQuotes( $lockName );
 938                 $result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
 939                 $row = $this->fetchObject( $result );
 940
 941                 return ( $row->lockstatus == 1 );
 942         }
 943
 944         public function namedLocksEnqueue() {
 945                 return true;
 946         }
 947
 948         /**
 949          * @param array $read
 950          * @param array $write
 951          * @param string $method
 952          * @param bool $lowPriority
 953          * @return bool
 954          */
 955         public function lockTables( $read, $write, $method, $lowPriority = true ) {
 956                 $items = array();
 957
 958                 foreach ( $write as $table ) {
 959                         $tbl = $this->tableName( $table ) .
 960                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
 961                                 ' WRITE';
 962                         $items[] = $tbl;
 963                 }
 964                 foreach ( $read as $table ) {
 965                         $items[] = $this->tableName( $table ) . ' READ';
 966                 }
 967                 $sql = "LOCK TABLES " . implode( ',', $items );
 968                 $this->query( $sql, $method );
 969
 970                 return true;
 971         }
 972
 973         /**
 974          * @param string $method
 975          * @return bool
 976          */
 977         public function unlockTables( $method ) {
 978                 $this->query( "UNLOCK TABLES", $method );
 979
 980                 return true;
 981         }
 982
 983         /**
 984          * Get search engine class. All subclasses of this
 985          * need to implement this if they wish to use searching.
 986          *
 987          * @return string
 988          */
 989         public function getSearchEngine() {
 990                 return 'SearchMySQL';
 991         }
 992
 993         /**
 994          * @param bool $value
 995          */
 996         public function setBigSelects( $value = true ) {
 997                 if ( $value === 'default' ) {
 998                         if ( $this->mDefaultBigSelects === null ) {
 999                                 # Function hasn't been called before so it must already be set to the default
1000                                 return;
1001                         } else {
1002                                 $value = $this->mDefaultBigSelects;
1003                         }
1004                 } elseif ( $this->mDefaultBigSelects === null ) {
1005                         $this->mDefaultBigSelects =
1006                                 (bool)$this->selectField( false, '@@sql_big_selects', '', __METHOD__ );
1007                 }
1008                 $encValue = $value ? '1' : '0';
1009                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
1010         }
1011
1012         /**
1013          * DELETE where the condition is a join. MySql uses multi-table deletes.
1014          * @param string $delTable
1015          * @param string $joinTable
1016          * @param string $delVar
1017          * @param string $joinVar
1018          * @param array|string $conds
1019          * @param bool|string $fname
1020          * @throws DBUnexpectedError
1021          * @return bool|ResultWrapper
1022          */
1023         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) {
1024                 if ( !$conds ) {
1025                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
1026                 }
1027
1028                 $delTable = $this->tableName( $delTable );
1029                 $joinTable = $this->tableName( $joinTable );
1030                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1031
1032                 if ( $conds != '*' ) {
1033                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1034                 }
1035
1036                 return $this->query( $sql, $fname );
1037         }
1038
1039         /**
1040          * @param string $table
1041          * @param array $rows
1042          * @param array $uniqueIndexes
1043          * @param array $set
1044          * @param string $fname
1045          * @return bool
1046          */
1047         public function upsert( $table, array $rows, array $uniqueIndexes,
1048                 array $set, $fname = __METHOD__
1049         ) {
1050                 if ( !count( $rows ) ) {
1051                         return true; // nothing to do
1052                 }
1053
1054                 if ( !is_array( reset( $rows ) ) ) {
1055                         $rows = array( $rows );
1056                 }
1057
1058                 $table = $this->tableName( $table );
1059                 $columns = array_keys( $rows[0] );
1060
1061                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
1062                 $rowTuples = array();
1063                 foreach ( $rows as $row ) {
1064                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
1065                 }
1066                 $sql .= implode( ',', $rowTuples );
1067                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, LIST_SET );
1068
1069                 return (bool)$this->query( $sql, $fname );
1070         }
1071
1072         /**
1073          * Determines how long the server has been up
1074          *
1075          * @return int
1076          */
1077         function getServerUptime() {
1078                 $vars = $this->getMysqlStatus( 'Uptime' );
1079
1080                 return (int)$vars['Uptime'];
1081         }
1082
1083         /**
1084          * Determines if the last failure was due to a deadlock
1085          *
1086          * @return bool
1087          */
1088         function wasDeadlock() {
1089                 return $this->lastErrno() == 1213;
1090         }
1091
1092         /**
1093          * Determines if the last failure was due to a lock timeout
1094          *
1095          * @return bool
1096          */
1097         function wasLockTimeout() {
1098                 return $this->lastErrno() == 1205;
1099         }
1100
1101         /**
1102          * Determines if the last query error was something that should be dealt
1103          * with by pinging the connection and reissuing the query
1104          *
1105          * @return bool
1106          */
1107         function wasErrorReissuable() {
1108                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
1109         }
1110
1111         /**
1112          * Determines if the last failure was due to the database being read-only.
1113          *
1114          * @return bool
1115          */
1116         function wasReadOnlyError() {
1117                 return $this->lastErrno() == 1223 ||
1118                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1119         }
1120
1121         function wasConnectionError( $errno ) {
1122                 return $errno == 2013 || $errno == 2006;
1123         }
1124
1125         /**
1126          * Get the underlying binding handle, mConn
1127          *
1128          * Makes sure that mConn is set (disconnects and ping() failure can unset it).
1129          * This catches broken callers than catch and ignore disconnection exceptions.
1130          * Unlike checking isOpen(), this is safe to call inside of open().
1131          *
1132          * @return resource|object
1133          * @throws DBUnexpectedError
1134          * @since 1.26
1135          */
1136         protected function getBindingHandle() {
1137                 if ( !$this->mConn ) {
1138                         throw new DBUnexpectedError(
1139                                 $this,
1140                                 'DB connection was already closed or the connection dropped.'
1141                         );
1142                 }
1143
1144                 return $this->mConn;
1145         }
1146
1147         /**
1148          * @param string $oldName
1149          * @param string $newName
1150          * @param bool $temporary
1151          * @param string $fname
1152          * @return bool
1153          */
1154         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1155                 $tmp = $temporary ? 'TEMPORARY ' : '';
1156                 $newName = $this->addIdentifierQuotes( $newName );
1157                 $oldName = $this->addIdentifierQuotes( $oldName );
1158                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1159
1160                 return $this->query( $query, $fname );
1161         }
1162
1163         /**
1164          * List all tables on the database
1165          *
1166          * @param string $prefix Only show tables with this prefix, e.g. mw_
1167          * @param string $fname Calling function name
1168          * @return array
1169          */
1170         function listTables( $prefix = null, $fname = __METHOD__ ) {
1171                 $result = $this->query( "SHOW TABLES", $fname );
1172
1173                 $endArray = array();
1174
1175                 foreach ( $result as $table ) {
1176                         $vars = get_object_vars( $table );
1177                         $table = array_pop( $vars );
1178
1179                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1180                                 $endArray[] = $table;
1181                         }
1182                 }
1183
1184                 return $endArray;
1185         }
1186
1187         /**
1188          * @param string $tableName
1189          * @param string $fName
1190          * @return bool|ResultWrapper
1191          */
1192         public function dropTable( $tableName, $fName = __METHOD__ ) {
1193                 if ( !$this->tableExists( $tableName, $fName ) ) {
1194                         return false;
1195                 }
1196
1197                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1198         }
1199
1200         /**
1201          * @return array
1202          */
1203         protected function getDefaultSchemaVars() {
1204                 $vars = parent::getDefaultSchemaVars();
1205                 $vars['wgDBTableOptions'] = str_replace( 'TYPE', 'ENGINE', $GLOBALS['wgDBTableOptions'] );
1206                 $vars['wgDBTableOptions'] = str_replace(
1207                         'CHARSET=mysql4',
1208                         'CHARSET=binary',
1209                         $vars['wgDBTableOptions']
1210                 );
1211
1212                 return $vars;
1213         }
1214
1215         /**
1216          * Get status information from SHOW STATUS in an associative array
1217          *
1218          * @param string $which
1219          * @return array
1220          */
1221         function getMysqlStatus( $which = "%" ) {
1222                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1223                 $status = array();
1224
1225                 foreach ( $res as $row ) {
1226                         $status[$row->Variable_name] = $row->Value;
1227                 }
1228
1229                 return $status;
1230         }
1231
1232         /**
1233          * Lists VIEWs in the database
1234          *
1235          * @param string $prefix Only show VIEWs with this prefix, eg.
1236          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1237          * @param string $fname Name of calling function
1238          * @return array
1239          * @since 1.22
1240          */
1241         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1242
1243                 if ( !isset( $this->allViews ) ) {
1244
1245                         // The name of the column containing the name of the VIEW
1246                         $propertyName = 'Tables_in_' . $this->mDBname;
1247
1248                         // Query for the VIEWS
1249                         $result = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1250                         $this->allViews = array();
1251                         while ( ( $row = $this->fetchRow( $result ) ) !== false ) {
1252                                 array_push( $this->allViews, $row[$propertyName] );
1253                         }
1254                 }
1255
1256                 if ( is_null( $prefix ) || $prefix === '' ) {
1257                         return $this->allViews;
1258                 }
1259
1260                 $filteredViews = array();
1261                 foreach ( $this->allViews as $viewName ) {
1262                         // Does the name of this VIEW start with the table-prefix?
1263                         if ( strpos( $viewName, $prefix ) === 0 ) {
1264                                 array_push( $filteredViews, $viewName );
1265                         }
1266                 }
1267
1268                 return $filteredViews;
1269         }
1270
1271         /**
1272          * Differentiates between a TABLE and a VIEW.
1273          *
1274          * @param string $name Name of the TABLE/VIEW to test
1275          * @param string $prefix
1276          * @return bool
1277          * @since 1.22
1278          */
1279         public function isView( $name, $prefix = null ) {
1280                 return in_array( $name, $this->listViews( $prefix ) );
1281         }
1282 }
1283
1284 /**
1285  * Utility class.
1286  * @ingroup Database
1287  */
1288 class MySQLField implements Field {
1289         private $name, $tablename, $default, $max_length, $nullable,
1290                 $is_pk, $is_unique, $is_multiple, $is_key, $type, $binary,
1291                 $is_numeric, $is_blob, $is_unsigned, $is_zerofill;
1292
1293         function __construct( $info ) {
1294                 $this->name = $info->name;
1295                 $this->tablename = $info->table;
1296                 $this->default = $info->def;
1297                 $this->max_length = $info->max_length;
1298                 $this->nullable = !$info->not_null;
1299                 $this->is_pk = $info->primary_key;
1300                 $this->is_unique = $info->unique_key;
1301                 $this->is_multiple = $info->multiple_key;
1302                 $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
1303                 $this->type = $info->type;
1304                 $this->binary = isset( $info->binary ) ? $info->binary : false;
1305                 $this->is_numeric = isset( $info->numeric ) ? $info->numeric : false;
1306                 $this->is_blob = isset( $info->blob ) ? $info->blob : false;
1307                 $this->is_unsigned = isset( $info->unsigned ) ? $info->unsigned : false;
1308                 $this->is_zerofill = isset( $info->zerofill ) ? $info->zerofill : false;
1309         }
1310
1311         /**
1312          * @return string
1313          */
1314         function name() {
1315                 return $this->name;
1316         }
1317
1318         /**
1319          * @return string
1320          */
1321         function tableName() {
1322                 return $this->tablename;
1323         }
1324
1325         /**
1326          * @return string
1327          */
1328         function type() {
1329                 return $this->type;
1330         }
1331
1332         /**
1333          * @return bool
1334          */
1335         function isNullable() {
1336                 return $this->nullable;
1337         }
1338
1339         function defaultValue() {
1340                 return $this->default;
1341         }
1342
1343         /**
1344          * @return bool
1345          */
1346         function isKey() {
1347                 return $this->is_key;
1348         }
1349
1350         /**
1351          * @return bool
1352          */
1353         function isMultipleKey() {
1354                 return $this->is_multiple;
1355         }
1356
1357         /**
1358          * @return bool
1359          */
1360         function isBinary() {
1361                 return $this->binary;
1362         }
1363
1364         /**
1365          * @return bool
1366          */
1367         function isNumeric() {
1368                 return $this->is_numeric;
1369         }
1370
1371         /**
1372          * @return bool
1373          */
1374         function isBlob() {
1375                 return $this->is_blob;
1376         }
1377
1378         /**
1379          * @return bool
1380          */
1381         function isUnsigned() {
1382                 return $this->is_unsigned;
1383         }
1384
1385         /**
1386          * @return bool
1387          */
1388         function isZerofill() {
1389                 return $this->is_zerofill;
1390         }
1391 }
1392
1393 class MySQLMasterPos implements DBMasterPos {
1394         /** @var string */
1395         public $file;
1396         /** @var int Position */
1397         public $pos;
1398         /** @var float UNIX timestamp */
1399         public $asOfTime = 0.0;
1400
1401         function __construct( $file, $pos ) {
1402                 $this->file = $file;
1403                 $this->pos = $pos;
1404                 $this->asOfTime = microtime( true );
1405         }
1406
1407         function asOfTime() {
1408                 return $this->asOfTime;
1409         }
1410
1411         function hasReached( DBMasterPos $pos ) {
1412                 if ( !( $pos instanceof self ) ) {
1413                         throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
1414                 }
1415
1416                 $thisPos = $this->getCoordinates();
1417                 $thatPos = $pos->getCoordinates();
1418
1419                 return ( $thisPos && $thatPos && $thisPos >= $thatPos );
1420         }
1421
1422         function __toString() {
1423                 // e.g db1034-bin.000976/843431247
1424                 return "{$this->file}/{$this->pos}";
1425         }
1426
1427         /**
1428          * @return array|bool (int, int)
1429          */
1430         protected function getCoordinates() {
1431                 $m = array();
1432                 if ( preg_match( '!\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
1433                         return array( (int)$m[1], (int)$m[2] );
1434                 }
1435
1436                 return false;
1437         }
1438 }