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