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                         wfLogDBError(
 658                                 "Unable to query master of {db_server} for server ID",
 659                                 $this->getLogContext( array(
 660                                         'method' => __METHOD__
 661                                 ) )
 662                         );
 663
 664                         return false; // could not get master server ID
 665                 }
 666
 667                 list( $time, $nowUnix ) = $this->getHeartbeatData( $masterInfo['serverId'] );
 668                 if ( $time !== null ) {
 669                         // @time is in ISO format like "2015-09-25T16:48:10.000510"
 670                         $dateTime = new DateTime( $time, new DateTimeZone( 'UTC' ) );
 671                         $timeUnix = (int)$dateTime->format( 'U' ) + $dateTime->format( 'u' ) / 1e6;
 672
 673                         return max( $nowUnix - $timeUnix, 0.0 );
 674                 }
 675
 676                 wfLogDBError(
 677                         "Unable to find pt-heartbeat row for {db_server}",
 678                         $this->getLogContext( array(
 679                                 'method' => __METHOD__
 680                         ) )
 681                 );
 682
 683                 return false;
 684         }
 685
 686         protected function getMasterServerInfo() {
 687                 $cache = $this->srvCache;
 688                 $key = $cache->makeGlobalKey(
 689                         'mysql',
 690                         'master-info',
 691                         // Using one key for all cluster slaves is preferable
 692                         $this->getLBInfo( 'clusterMasterHost' ) ?: $this->getServer()
 693                 );
 694
 695                 return $cache->getWithSetCallback(
 696                         $key,
 697                         $cache::TTL_INDEFINITE,
 698                         function () use ( $cache, $key ) {
 699                                 // Get and leave a lock key in place for a short period
 700                                 if ( !$cache->lock( $key, 0, 10 ) ) {
 701                                         return false; // avoid master connection spike slams
 702                                 }
 703
 704                                 $conn = $this->getLazyMasterHandle();
 705                                 if ( !$conn ) {
 706                                         return false; // something is misconfigured
 707                                 }
 708
 709                                 // Connect to and query the master; catch errors to avoid outages
 710                                 try {
 711                                         $res = $conn->query( 'SELECT @@server_id AS id', __METHOD__ );
 712                                         $row = $res ? $res->fetchObject() : false;
 713                                         $id = $row ? (int)$row->id : 0;
 714                                 } catch ( DBError $e ) {
 715                                         $id = 0;
 716                                 }
 717
 718                                 // Cache the ID if it was retrieved
 719                                 return $id ? array( 'serverId' => $id, 'asOf' => time() ) : false;
 720                         }
 721                 );
 722         }
 723
 724         /**
 725          * @param string $masterId Server ID
 726          * @return array (heartbeat `ts` column value or null, UNIX timestamp)
 727          * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html
 728          */
 729         protected function getHeartbeatData( $masterId ) {
 730                 // Get the status row for this master; use the oldest for sanity in case the master
 731                 // has entries listed under different server IDs (which should really not happen).
 732                 // Note: this would use "MAX(TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6)))" but the
 733                 // percision field is not supported in MySQL <= 5.5.
 734                 $res = $this->query(
 735                         "SELECT ts FROM heartbeat.heartbeat WHERE server_id=" . intval( $masterId )
 736                 );
 737                 $row = $res ? $res->fetchObject() : false;
 738
 739                 return array( $row ? $row->ts : null, microtime( true ) );
 740         }
 741
 742         public function getApproximateLagStatus() {
 743                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 744                         // Disable caching since this is fast enough and we don't wan't
 745                         // to be *too* pessimistic by having both the cache TTL and the
 746                         // pt-heartbeat interval count as lag in getSessionLagStatus()
 747                         return parent::getApproximateLagStatus();
 748                 }
 749
 750                 $key = $this->srvCache->makeGlobalKey( 'mysql-lag', $this->getServer() );
 751                 $approxLag = $this->srvCache->get( $key );
 752                 if ( !$approxLag ) {
 753                         $approxLag = parent::getApproximateLagStatus();
 754                         $this->srvCache->set( $key, $approxLag, 1 );
 755                 }
 756
 757                 return $approxLag;
 758         }
 759
 760         /**
 761          * Wait for the slave to catch up to a given master position.
 762          * @todo Return values for this and base class are rubbish
 763          *
 764          * @param DBMasterPos|MySQLMasterPos $pos
 765          * @param int $timeout The maximum number of seconds to wait for synchronisation
 766          * @return int Zero if the slave was past that position already,
 767          *   greater than zero if we waited for some period of time, less than
 768          *   zero if we timed out.
 769          */
 770         function masterPosWait( DBMasterPos $pos, $timeout ) {
 771                 if ( $this->lastKnownSlavePos && $this->lastKnownSlavePos->hasReached( $pos ) ) {
 772                         return '0'; // http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html
 773                 }
 774
 775                 # Commit any open transactions
 776                 $this->commit( __METHOD__, 'flush' );
 777
 778                 # Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 779                 $encFile = $this->addQuotes( $pos->file );
 780                 $encPos = intval( $pos->pos );
 781                 $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 782                 $res = $this->doQuery( $sql );
 783
 784                 $status = false;
 785                 if ( $res ) {
 786                         $row = $this->fetchRow( $res );
 787                         if ( $row ) {
 788                                 $status = $row[0]; // can be NULL, -1, or 0+ per the MySQL manual
 789                                 if ( ctype_digit( $status ) ) { // success
 790                                         $this->lastKnownSlavePos = $pos;
 791                                 }
 792                         }
 793                 }
 794
 795                 return $status;
 796         }
 797
 798         /**
 799          * Get the position of the master from SHOW SLAVE STATUS
 800          *
 801          * @return MySQLMasterPos|bool
 802          */
 803         function getSlavePos() {
 804                 $res = $this->query( 'SHOW SLAVE STATUS', 'DatabaseBase::getSlavePos' );
 805                 $row = $this->fetchObject( $res );
 806
 807                 if ( $row ) {
 808                         $pos = isset( $row->Exec_master_log_pos )
 809                                 ? $row->Exec_master_log_pos
 810                                 : $row->Exec_Master_Log_Pos;
 811
 812                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos );
 813                 } else {
 814                         return false;
 815                 }
 816         }
 817
 818         /**
 819          * Get the position of the master from SHOW MASTER STATUS
 820          *
 821          * @return MySQLMasterPos|bool
 822          */
 823         function getMasterPos() {
 824                 $res = $this->query( 'SHOW MASTER STATUS', 'DatabaseBase::getMasterPos' );
 825                 $row = $this->fetchObject( $res );
 826
 827                 if ( $row ) {
 828                         return new MySQLMasterPos( $row->File, $row->Position );
 829                 } else {
 830                         return false;
 831                 }
 832         }
 833
 834         /**
 835          * @param string $index
 836          * @return string
 837          */
 838         function useIndexClause( $index ) {
 839                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 840         }
 841
 842         /**
 843          * @return string
 844          */
 845         function lowPriorityOption() {
 846                 return 'LOW_PRIORITY';
 847         }
 848
 849         /**
 850          * @return string
 851          */
 852         public function getSoftwareLink() {
 853                 // MariaDB includes its name in its version string; this is how MariaDB's version of
 854                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
 855                 // in libmysql/libmysql.c).
 856                 $version = $this->getServerVersion();
 857                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 858                         return '[{{int:version-db-mariadb-url}} MariaDB]';
 859                 }
 860
 861                 // Percona Server's version suffix is not very distinctive, and @@version_comment
 862                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
 863                 // (Even Percona's version of mysql doesn't try to make the distinction.)
 864                 return '[{{int:version-db-mysql-url}} MySQL]';
 865         }
 866
 867         /**
 868          * @return string
 869          */
 870         public function getServerVersion() {
 871                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
 872                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
 873                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
 874                 if ( $this->serverVersion === null ) {
 875                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
 876                 }
 877                 return $this->serverVersion;
 878         }
 879
 880         /**
 881          * @param array $options
 882          */
 883         public function setSessionOptions( array $options ) {
 884                 if ( isset( $options['connTimeout'] ) ) {
 885                         $timeout = (int)$options['connTimeout'];
 886                         $this->query( "SET net_read_timeout=$timeout" );
 887                         $this->query( "SET net_write_timeout=$timeout" );
 888                 }
 889         }
 890
 891         /**
 892          * @param string $sql
 893          * @param string $newLine
 894          * @return bool
 895          */
 896         public function streamStatementEnd( &$sql, &$newLine ) {
 897                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 898                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 899                         $this->delimiter = $m[1];
 900                         $newLine = '';
 901                 }
 902
 903                 return parent::streamStatementEnd( $sql, $newLine );
 904         }
 905
 906         /**
 907          * Check to see if a named lock is available. This is non-blocking.
 908          *
 909          * @param string $lockName Name of lock to poll
 910          * @param string $method Name of method calling us
 911          * @return bool
 912          * @since 1.20
 913          */
 914         public function lockIsFree( $lockName, $method ) {
 915                 $lockName = $this->addQuotes( $this->makeLockName( $lockName ) );
 916                 $result = $this->query( "SELECT IS_FREE_LOCK($lockName) AS lockstatus", $method );
 917                 $row = $this->fetchObject( $result );
 918
 919                 return ( $row->lockstatus == 1 );
 920         }
 921
 922         /**
 923          * @param string $lockName
 924          * @param string $method
 925          * @param int $timeout
 926          * @return bool
 927          */
 928         public function lock( $lockName, $method, $timeout = 5 ) {
 929                 $lockName = $this->addQuotes( $this->makeLockName( $lockName ) );
 930                 $result = $this->query( "SELECT GET_LOCK($lockName, $timeout) AS lockstatus", $method );
 931                 $row = $this->fetchObject( $result );
 932
 933                 if ( $row->lockstatus == 1 ) {
 934                         parent::lock( $lockName, $method, $timeout ); // record
 935                         return true;
 936                 }
 937
 938                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
 939
 940                 return false;
 941         }
 942
 943         /**
 944          * FROM MYSQL DOCS:
 945          * http://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
 946          * @param string $lockName
 947          * @param string $method
 948          * @return bool
 949          */
 950         public function unlock( $lockName, $method ) {
 951                 $lockName = $this->addQuotes( $this->makeLockName( $lockName ) );
 952                 $result = $this->query( "SELECT RELEASE_LOCK($lockName) as lockstatus", $method );
 953                 $row = $this->fetchObject( $result );
 954
 955                 if ( $row->lockstatus == 1 ) {
 956                         parent::unlock( $lockName, $method ); // record
 957                         return true;
 958                 }
 959
 960                 wfDebug( __METHOD__ . " failed to release lock\n" );
 961
 962                 return false;
 963         }
 964
 965         private function makeLockName( $lockName ) {
 966                 // http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
 967                 // Newer version enforce a 64 char length limit.
 968                 return ( strlen( $lockName ) > 64 ) ? sha1( $lockName ) : $lockName;
 969         }
 970
 971         public function namedLocksEnqueue() {
 972                 return true;
 973         }
 974
 975         /**
 976          * @param array $read
 977          * @param array $write
 978          * @param string $method
 979          * @param bool $lowPriority
 980          * @return bool
 981          */
 982         public function lockTables( $read, $write, $method, $lowPriority = true ) {
 983                 $items = array();
 984
 985                 foreach ( $write as $table ) {
 986                         $tbl = $this->tableName( $table ) .
 987                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
 988                                 ' WRITE';
 989                         $items[] = $tbl;
 990                 }
 991                 foreach ( $read as $table ) {
 992                         $items[] = $this->tableName( $table ) . ' READ';
 993                 }
 994                 $sql = "LOCK TABLES " . implode( ',', $items );
 995                 $this->query( $sql, $method );
 996
 997                 return true;
 998         }
 999
1000         /**
1001          * @param string $method
1002          * @return bool
1003          */
1004         public function unlockTables( $method ) {
1005                 $this->query( "UNLOCK TABLES", $method );
1006
1007                 return true;
1008         }
1009
1010         /**
1011          * Get search engine class. All subclasses of this
1012          * need to implement this if they wish to use searching.
1013          *
1014          * @return string
1015          */
1016         public function getSearchEngine() {
1017                 return 'SearchMySQL';
1018         }
1019
1020         /**
1021          * @param bool $value
1022          */
1023         public function setBigSelects( $value = true ) {
1024                 if ( $value === 'default' ) {
1025                         if ( $this->mDefaultBigSelects === null ) {
1026                                 # Function hasn't been called before so it must already be set to the default
1027                                 return;
1028                         } else {
1029                                 $value = $this->mDefaultBigSelects;
1030                         }
1031                 } elseif ( $this->mDefaultBigSelects === null ) {
1032                         $this->mDefaultBigSelects =
1033                                 (bool)$this->selectField( false, '@@sql_big_selects', '', __METHOD__ );
1034                 }
1035                 $encValue = $value ? '1' : '0';
1036                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
1037         }
1038
1039         /**
1040          * DELETE where the condition is a join. MySql uses multi-table deletes.
1041          * @param string $delTable
1042          * @param string $joinTable
1043          * @param string $delVar
1044          * @param string $joinVar
1045          * @param array|string $conds
1046          * @param bool|string $fname
1047          * @throws DBUnexpectedError
1048          * @return bool|ResultWrapper
1049          */
1050         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__ ) {
1051                 if ( !$conds ) {
1052                         throw new DBUnexpectedError( $this, 'DatabaseBase::deleteJoin() called with empty $conds' );
1053                 }
1054
1055                 $delTable = $this->tableName( $delTable );
1056                 $joinTable = $this->tableName( $joinTable );
1057                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1058
1059                 if ( $conds != '*' ) {
1060                         $sql .= ' AND ' . $this->makeList( $conds, LIST_AND );
1061                 }
1062
1063                 return $this->query( $sql, $fname );
1064         }
1065
1066         /**
1067          * @param string $table
1068          * @param array $rows
1069          * @param array $uniqueIndexes
1070          * @param array $set
1071          * @param string $fname
1072          * @return bool
1073          */
1074         public function upsert( $table, array $rows, array $uniqueIndexes,
1075                 array $set, $fname = __METHOD__
1076         ) {
1077                 if ( !count( $rows ) ) {
1078                         return true; // nothing to do
1079                 }
1080
1081                 if ( !is_array( reset( $rows ) ) ) {
1082                         $rows = array( $rows );
1083                 }
1084
1085                 $table = $this->tableName( $table );
1086                 $columns = array_keys( $rows[0] );
1087
1088                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
1089                 $rowTuples = array();
1090                 foreach ( $rows as $row ) {
1091                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
1092                 }
1093                 $sql .= implode( ',', $rowTuples );
1094                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, LIST_SET );
1095
1096                 return (bool)$this->query( $sql, $fname );
1097         }
1098
1099         /**
1100          * Determines how long the server has been up
1101          *
1102          * @return int
1103          */
1104         function getServerUptime() {
1105                 $vars = $this->getMysqlStatus( 'Uptime' );
1106
1107                 return (int)$vars['Uptime'];
1108         }
1109
1110         /**
1111          * Determines if the last failure was due to a deadlock
1112          *
1113          * @return bool
1114          */
1115         function wasDeadlock() {
1116                 return $this->lastErrno() == 1213;
1117         }
1118
1119         /**
1120          * Determines if the last failure was due to a lock timeout
1121          *
1122          * @return bool
1123          */
1124         function wasLockTimeout() {
1125                 return $this->lastErrno() == 1205;
1126         }
1127
1128         /**
1129          * Determines if the last query error was something that should be dealt
1130          * with by pinging the connection and reissuing the query
1131          *
1132          * @return bool
1133          */
1134         function wasErrorReissuable() {
1135                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
1136         }
1137
1138         /**
1139          * Determines if the last failure was due to the database being read-only.
1140          *
1141          * @return bool
1142          */
1143         function wasReadOnlyError() {
1144                 return $this->lastErrno() == 1223 ||
1145                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1146         }
1147
1148         function wasConnectionError( $errno ) {
1149                 return $errno == 2013 || $errno == 2006;
1150         }
1151
1152         /**
1153          * Get the underlying binding handle, mConn
1154          *
1155          * Makes sure that mConn is set (disconnects and ping() failure can unset it).
1156          * This catches broken callers than catch and ignore disconnection exceptions.
1157          * Unlike checking isOpen(), this is safe to call inside of open().
1158          *
1159          * @return resource|object
1160          * @throws DBUnexpectedError
1161          * @since 1.26
1162          */
1163         protected function getBindingHandle() {
1164                 if ( !$this->mConn ) {
1165                         throw new DBUnexpectedError(
1166                                 $this,
1167                                 'DB connection was already closed or the connection dropped.'
1168                         );
1169                 }
1170
1171                 return $this->mConn;
1172         }
1173
1174         /**
1175          * @param string $oldName
1176          * @param string $newName
1177          * @param bool $temporary
1178          * @param string $fname
1179          * @return bool
1180          */
1181         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1182                 $tmp = $temporary ? 'TEMPORARY ' : '';
1183                 $newName = $this->addIdentifierQuotes( $newName );
1184                 $oldName = $this->addIdentifierQuotes( $oldName );
1185                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1186
1187                 return $this->query( $query, $fname );
1188         }
1189
1190         /**
1191          * List all tables on the database
1192          *
1193          * @param string $prefix Only show tables with this prefix, e.g. mw_
1194          * @param string $fname Calling function name
1195          * @return array
1196          */
1197         function listTables( $prefix = null, $fname = __METHOD__ ) {
1198                 $result = $this->query( "SHOW TABLES", $fname );
1199
1200                 $endArray = array();
1201
1202                 foreach ( $result as $table ) {
1203                         $vars = get_object_vars( $table );
1204                         $table = array_pop( $vars );
1205
1206                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1207                                 $endArray[] = $table;
1208                         }
1209                 }
1210
1211                 return $endArray;
1212         }
1213
1214         /**
1215          * @param string $tableName
1216          * @param string $fName
1217          * @return bool|ResultWrapper
1218          */
1219         public function dropTable( $tableName, $fName = __METHOD__ ) {
1220                 if ( !$this->tableExists( $tableName, $fName ) ) {
1221                         return false;
1222                 }
1223
1224                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1225         }
1226
1227         /**
1228          * @return array
1229          */
1230         protected function getDefaultSchemaVars() {
1231                 $vars = parent::getDefaultSchemaVars();
1232                 $vars['wgDBTableOptions'] = str_replace( 'TYPE', 'ENGINE', $GLOBALS['wgDBTableOptions'] );
1233                 $vars['wgDBTableOptions'] = str_replace(
1234                         'CHARSET=mysql4',
1235                         'CHARSET=binary',
1236                         $vars['wgDBTableOptions']
1237                 );
1238
1239                 return $vars;
1240         }
1241
1242         /**
1243          * Get status information from SHOW STATUS in an associative array
1244          *
1245          * @param string $which
1246          * @return array
1247          */
1248         function getMysqlStatus( $which = "%" ) {
1249                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1250                 $status = array();
1251
1252                 foreach ( $res as $row ) {
1253                         $status[$row->Variable_name] = $row->Value;
1254                 }
1255
1256                 return $status;
1257         }
1258
1259         /**
1260          * Lists VIEWs in the database
1261          *
1262          * @param string $prefix Only show VIEWs with this prefix, eg.
1263          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1264          * @param string $fname Name of calling function
1265          * @return array
1266          * @since 1.22
1267          */
1268         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1269
1270                 if ( !isset( $this->allViews ) ) {
1271
1272                         // The name of the column containing the name of the VIEW
1273                         $propertyName = 'Tables_in_' . $this->mDBname;
1274
1275                         // Query for the VIEWS
1276                         $result = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1277                         $this->allViews = array();
1278                         while ( ( $row = $this->fetchRow( $result ) ) !== false ) {
1279                                 array_push( $this->allViews, $row[$propertyName] );
1280                         }
1281                 }
1282
1283                 if ( is_null( $prefix ) || $prefix === '' ) {
1284                         return $this->allViews;
1285                 }
1286
1287                 $filteredViews = array();
1288                 foreach ( $this->allViews as $viewName ) {
1289                         // Does the name of this VIEW start with the table-prefix?
1290                         if ( strpos( $viewName, $prefix ) === 0 ) {
1291                                 array_push( $filteredViews, $viewName );
1292                         }
1293                 }
1294
1295                 return $filteredViews;
1296         }
1297
1298         /**
1299          * Differentiates between a TABLE and a VIEW.
1300          *
1301          * @param string $name Name of the TABLE/VIEW to test
1302          * @param string $prefix
1303          * @return bool
1304          * @since 1.22
1305          */
1306         public function isView( $name, $prefix = null ) {
1307                 return in_array( $name, $this->listViews( $prefix ) );
1308         }
1309 }
1310
1311 /**
1312  * Utility class.
1313  * @ingroup Database
1314  */
1315 class MySQLField implements Field {
1316         private $name, $tablename, $default, $max_length, $nullable,
1317                 $is_pk, $is_unique, $is_multiple, $is_key, $type, $binary,
1318                 $is_numeric, $is_blob, $is_unsigned, $is_zerofill;
1319
1320         function __construct( $info ) {
1321                 $this->name = $info->name;
1322                 $this->tablename = $info->table;
1323                 $this->default = $info->def;
1324                 $this->max_length = $info->max_length;
1325                 $this->nullable = !$info->not_null;
1326                 $this->is_pk = $info->primary_key;
1327                 $this->is_unique = $info->unique_key;
1328                 $this->is_multiple = $info->multiple_key;
1329                 $this->is_key = ( $this->is_pk || $this->is_unique || $this->is_multiple );
1330                 $this->type = $info->type;
1331                 $this->binary = isset( $info->binary ) ? $info->binary : false;
1332                 $this->is_numeric = isset( $info->numeric ) ? $info->numeric : false;
1333                 $this->is_blob = isset( $info->blob ) ? $info->blob : false;
1334                 $this->is_unsigned = isset( $info->unsigned ) ? $info->unsigned : false;
1335                 $this->is_zerofill = isset( $info->zerofill ) ? $info->zerofill : false;
1336         }
1337
1338         /**
1339          * @return string
1340          */
1341         function name() {
1342                 return $this->name;
1343         }
1344
1345         /**
1346          * @return string
1347          */
1348         function tableName() {
1349                 return $this->tablename;
1350         }
1351
1352         /**
1353          * @return string
1354          */
1355         function type() {
1356                 return $this->type;
1357         }
1358
1359         /**
1360          * @return bool
1361          */
1362         function isNullable() {
1363                 return $this->nullable;
1364         }
1365
1366         function defaultValue() {
1367                 return $this->default;
1368         }
1369
1370         /**
1371          * @return bool
1372          */
1373         function isKey() {
1374                 return $this->is_key;
1375         }
1376
1377         /**
1378          * @return bool
1379          */
1380         function isMultipleKey() {
1381                 return $this->is_multiple;
1382         }
1383
1384         /**
1385          * @return bool
1386          */
1387         function isBinary() {
1388                 return $this->binary;
1389         }
1390
1391         /**
1392          * @return bool
1393          */
1394         function isNumeric() {
1395                 return $this->is_numeric;
1396         }
1397
1398         /**
1399          * @return bool
1400          */
1401         function isBlob() {
1402                 return $this->is_blob;
1403         }
1404
1405         /**
1406          * @return bool
1407          */
1408         function isUnsigned() {
1409                 return $this->is_unsigned;
1410         }
1411
1412         /**
1413          * @return bool
1414          */
1415         function isZerofill() {
1416                 return $this->is_zerofill;
1417         }
1418 }
1419
1420 class MySQLMasterPos implements DBMasterPos {
1421         /** @var string */
1422         public $file;
1423         /** @var int Position */
1424         public $pos;
1425         /** @var float UNIX timestamp */
1426         public $asOfTime = 0.0;
1427
1428         function __construct( $file, $pos ) {
1429                 $this->file = $file;
1430                 $this->pos = $pos;
1431                 $this->asOfTime = microtime( true );
1432         }
1433
1434         function asOfTime() {
1435                 return $this->asOfTime;
1436         }
1437
1438         function hasReached( DBMasterPos $pos ) {
1439                 if ( !( $pos instanceof self ) ) {
1440                         throw new InvalidArgumentException( "Position not an instance of " . __CLASS__ );
1441                 }
1442
1443                 $thisPos = $this->getCoordinates();
1444                 $thatPos = $pos->getCoordinates();
1445
1446                 return ( $thisPos && $thatPos && $thisPos >= $thatPos );
1447         }
1448
1449         function __toString() {
1450                 // e.g db1034-bin.000976/843431247
1451                 return "{$this->file}/{$this->pos}";
1452         }
1453
1454         /**
1455          * @return array|bool (int, int)
1456          */
1457         protected function getCoordinates() {
1458                 $m = array();
1459                 if ( preg_match( '!\.(\d+)/(\d+)$!', (string)$this, $m ) ) {
1460                         return array( (int)$m[1], (int)$m[2] );
1461                 }
1462
1463                 return false;
1464         }
1465 }