includes/libs/rdbms/database/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 use Wikimedia\Rdbms\DBMasterPos;
  24 use Wikimedia\Rdbms\MySQLMasterPos;
  25 use Wikimedia\Rdbms\MySQLField;
  26
  27 /**
  28  * Database abstraction object for MySQL.
  29  * Defines methods independent on used MySQL extension.
  30  *
  31  * @ingroup Database
  32  * @since 1.22
  33  * @see Database
  34  */
  35 abstract class DatabaseMysqlBase extends Database {
  36         /** @var MysqlMasterPos */
  37         protected $lastKnownReplicaPos;
  38         /** @var string Method to detect replica DB lag */
  39         protected $lagDetectionMethod;
  40         /** @var array Method to detect replica DB lag */
  41         protected $lagDetectionOptions = [];
  42         /** @var bool bool Whether to use GTID methods */
  43         protected $useGTIDs = false;
  44         /** @var string|null */
  45         protected $sslKeyPath;
  46         /** @var string|null */
  47         protected $sslCertPath;
  48         /** @var string|null */
  49         protected $sslCAPath;
  50         /** @var string[]|null */
  51         protected $sslCiphers;
  52         /** @var string sql_mode value to send on connection */
  53         protected $sqlMode;
  54         /** @var bool Use experimental UTF-8 transmission encoding */
  55         protected $utf8Mode;
  56
  57         /** @var string|null */
  58         private $serverVersion = null;
  59
  60         /**
  61          * Additional $params include:
  62          *   - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat).
  63          *       pt-heartbeat assumes the table is at heartbeat.heartbeat
  64          *       and uses UTC timestamps in the heartbeat.ts column.
  65          *       (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html)
  66          *   - lagDetectionOptions : if using pt-heartbeat, this can be set to an array map to change
  67          *       the default behavior. Normally, the heartbeat row with the server
  68          *       ID of this server's master will be used. Set the "conds" field to
  69          *       override the query conditions, e.g. ['shard' => 's1'].
  70          *   - useGTIDs : use GTID methods like MASTER_GTID_WAIT() when possible.
  71          *   - sslKeyPath : path to key file [default: null]
  72          *   - sslCertPath : path to certificate file [default: null]
  73          *   - sslCAPath : parth to certificate authority PEM files [default: null]
  74          *   - sslCiphers : array list of allowable ciphers [default: null]
  75          * @param array $params
  76          */
  77         function __construct( array $params ) {
  78                 $this->lagDetectionMethod = isset( $params['lagDetectionMethod'] )
  79                         ? $params['lagDetectionMethod']
  80                         : 'Seconds_Behind_Master';
  81                 $this->lagDetectionOptions = isset( $params['lagDetectionOptions'] )
  82                         ? $params['lagDetectionOptions']
  83                         : [];
  84                 $this->useGTIDs = !empty( $params['useGTIDs' ] );
  85                 foreach ( [ 'KeyPath', 'CertPath', 'CAPath', 'Ciphers' ] as $name ) {
  86                         $var = "ssl{$name}";
  87                         if ( isset( $params[$var] ) ) {
  88                                 $this->$var = $params[$var];
  89                         }
  90                 }
  91                 $this->sqlMode = isset( $params['sqlMode'] ) ? $params['sqlMode'] : '';
  92                 $this->utf8Mode = !empty( $params['utf8Mode'] );
  93
  94                 parent::__construct( $params );
  95         }
  96
  97         /**
  98          * @return string
  99          */
 100         public function getType() {
 101                 return 'mysql';
 102         }
 103
 104         /**
 105          * @param string $server
 106          * @param string $user
 107          * @param string $password
 108          * @param string $dbName
 109          * @throws Exception|DBConnectionError
 110          * @return bool
 111          */
 112         public function open( $server, $user, $password, $dbName ) {
 113                 # Close/unset connection handle
 114                 $this->close();
 115
 116                 $this->mServer = $server;
 117                 $this->mUser = $user;
 118                 $this->mPassword = $password;
 119                 $this->mDBname = $dbName;
 120
 121                 $this->installErrorHandler();
 122                 try {
 123                         $this->mConn = $this->mysqlConnect( $this->mServer );
 124                 } catch ( Exception $ex ) {
 125                         $this->restoreErrorHandler();
 126                         throw $ex;
 127                 }
 128                 $error = $this->restoreErrorHandler();
 129
 130                 # Always log connection errors
 131                 if ( !$this->mConn ) {
 132                         if ( !$error ) {
 133                                 $error = $this->lastError();
 134                         }
 135                         $this->connLogger->error(
 136                                 "Error connecting to {db_server}: {error}",
 137                                 $this->getLogContext( [
 138                                         'method' => __METHOD__,
 139                                         'error' => $error,
 140                                 ] )
 141                         );
 142                         $this->connLogger->debug( "DB connection error\n" .
 143                                 "Server: $server, User: $user, Password: " .
 144                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 145
 146                         $this->reportConnectionError( $error );
 147                 }
 148
 149                 if ( $dbName != '' ) {
 150                         MediaWiki\suppressWarnings();
 151                         $success = $this->selectDB( $dbName );
 152                         MediaWiki\restoreWarnings();
 153                         if ( !$success ) {
 154                                 $this->queryLogger->error(
 155                                         "Error selecting database {db_name} on server {db_server}",
 156                                         $this->getLogContext( [
 157                                                 'method' => __METHOD__,
 158                                         ] )
 159                                 );
 160                                 $this->queryLogger->debug(
 161                                         "Error selecting database $dbName on server {$this->mServer}" );
 162
 163                                 $this->reportConnectionError( "Error selecting database $dbName" );
 164                         }
 165                 }
 166
 167                 // Tell the server what we're communicating with
 168                 if ( !$this->connectInitCharset() ) {
 169                         $this->reportConnectionError( "Error setting character set" );
 170                 }
 171
 172                 // Abstract over any insane MySQL defaults
 173                 $set = [ 'group_concat_max_len = 262144' ];
 174                 // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 175                 if ( is_string( $this->sqlMode ) ) {
 176                         $set[] = 'sql_mode = ' . $this->addQuotes( $this->sqlMode );
 177                 }
 178                 // Set any custom settings defined by site config
 179                 // (e.g. https://dev.mysql.com/doc/refman/4.1/en/innodb-parameters.html)
 180                 foreach ( $this->mSessionVars as $var => $val ) {
 181                         // Escape strings but not numbers to avoid MySQL complaining
 182                         if ( !is_int( $val ) && !is_float( $val ) ) {
 183                                 $val = $this->addQuotes( $val );
 184                         }
 185                         $set[] = $this->addIdentifierQuotes( $var ) . ' = ' . $val;
 186                 }
 187
 188                 if ( $set ) {
 189                         // Use doQuery() to avoid opening implicit transactions (DBO_TRX)
 190                         $success = $this->doQuery( 'SET ' . implode( ', ', $set ) );
 191                         if ( !$success ) {
 192                                 $this->queryLogger->error(
 193                                         'Error setting MySQL variables on server {db_server} (check $wgSQLMode)',
 194                                         $this->getLogContext( [
 195                                                 'method' => __METHOD__,
 196                                         ] )
 197                                 );
 198                                 $this->reportConnectionError(
 199                                         'Error setting MySQL variables on server {db_server} (check $wgSQLMode)' );
 200                         }
 201                 }
 202
 203                 $this->mOpened = true;
 204
 205                 return true;
 206         }
 207
 208         /**
 209          * Set the character set information right after connection
 210          * @return bool
 211          */
 212         protected function connectInitCharset() {
 213                 if ( $this->utf8Mode ) {
 214                         // Tell the server we're communicating with it in UTF-8.
 215                         // This may engage various charset conversions.
 216                         return $this->mysqlSetCharset( 'utf8' );
 217                 } else {
 218                         return $this->mysqlSetCharset( 'binary' );
 219                 }
 220         }
 221
 222         /**
 223          * Open a connection to a MySQL server
 224          *
 225          * @param string $realServer
 226          * @return mixed Raw connection
 227          * @throws DBConnectionError
 228          */
 229         abstract protected function mysqlConnect( $realServer );
 230
 231         /**
 232          * Set the character set of the MySQL link
 233          *
 234          * @param string $charset
 235          * @return bool
 236          */
 237         abstract protected function mysqlSetCharset( $charset );
 238
 239         /**
 240          * @param ResultWrapper|resource $res
 241          * @throws DBUnexpectedError
 242          */
 243         public function freeResult( $res ) {
 244                 if ( $res instanceof ResultWrapper ) {
 245                         $res = $res->result;
 246                 }
 247                 MediaWiki\suppressWarnings();
 248                 $ok = $this->mysqlFreeResult( $res );
 249                 MediaWiki\restoreWarnings();
 250                 if ( !$ok ) {
 251                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 252                 }
 253         }
 254
 255         /**
 256          * Free result memory
 257          *
 258          * @param resource $res Raw result
 259          * @return bool
 260          */
 261         abstract protected function mysqlFreeResult( $res );
 262
 263         /**
 264          * @param ResultWrapper|resource $res
 265          * @return stdClass|bool
 266          * @throws DBUnexpectedError
 267          */
 268         public function fetchObject( $res ) {
 269                 if ( $res instanceof ResultWrapper ) {
 270                         $res = $res->result;
 271                 }
 272                 MediaWiki\suppressWarnings();
 273                 $row = $this->mysqlFetchObject( $res );
 274                 MediaWiki\restoreWarnings();
 275
 276                 $errno = $this->lastErrno();
 277                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 278                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 279                 // these are the only errors mysql_fetch_object can cause.
 280                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 281                 if ( $errno == 2000 || $errno == 2013 ) {
 282                         throw new DBUnexpectedError(
 283                                 $this,
 284                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 285                         );
 286                 }
 287
 288                 return $row;
 289         }
 290
 291         /**
 292          * Fetch a result row as an object
 293          *
 294          * @param resource $res Raw result
 295          * @return stdClass
 296          */
 297         abstract protected function mysqlFetchObject( $res );
 298
 299         /**
 300          * @param ResultWrapper|resource $res
 301          * @return array|bool
 302          * @throws DBUnexpectedError
 303          */
 304         public function fetchRow( $res ) {
 305                 if ( $res instanceof ResultWrapper ) {
 306                         $res = $res->result;
 307                 }
 308                 MediaWiki\suppressWarnings();
 309                 $row = $this->mysqlFetchArray( $res );
 310                 MediaWiki\restoreWarnings();
 311
 312                 $errno = $this->lastErrno();
 313                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 314                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 315                 // these are the only errors mysql_fetch_array can cause.
 316                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 317                 if ( $errno == 2000 || $errno == 2013 ) {
 318                         throw new DBUnexpectedError(
 319                                 $this,
 320                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 321                         );
 322                 }
 323
 324                 return $row;
 325         }
 326
 327         /**
 328          * Fetch a result row as an associative and numeric array
 329          *
 330          * @param resource $res Raw result
 331          * @return array
 332          */
 333         abstract protected function mysqlFetchArray( $res );
 334
 335         /**
 336          * @throws DBUnexpectedError
 337          * @param ResultWrapper|resource $res
 338          * @return int
 339          */
 340         function numRows( $res ) {
 341                 if ( $res instanceof ResultWrapper ) {
 342                         $res = $res->result;
 343                 }
 344                 MediaWiki\suppressWarnings();
 345                 $n = $this->mysqlNumRows( $res );
 346                 MediaWiki\restoreWarnings();
 347
 348                 // Unfortunately, mysql_num_rows does not reset the last errno.
 349                 // We are not checking for any errors here, since
 350                 // these are no errors mysql_num_rows can cause.
 351                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 352                 // See https://phabricator.wikimedia.org/T44430
 353                 return $n;
 354         }
 355
 356         /**
 357          * Get number of rows in result
 358          *
 359          * @param resource $res Raw result
 360          * @return int
 361          */
 362         abstract protected function mysqlNumRows( $res );
 363
 364         /**
 365          * @param ResultWrapper|resource $res
 366          * @return int
 367          */
 368         public function numFields( $res ) {
 369                 if ( $res instanceof ResultWrapper ) {
 370                         $res = $res->result;
 371                 }
 372
 373                 return $this->mysqlNumFields( $res );
 374         }
 375
 376         /**
 377          * Get number of fields in result
 378          *
 379          * @param resource $res Raw result
 380          * @return int
 381          */
 382         abstract protected function mysqlNumFields( $res );
 383
 384         /**
 385          * @param ResultWrapper|resource $res
 386          * @param int $n
 387          * @return string
 388          */
 389         public function fieldName( $res, $n ) {
 390                 if ( $res instanceof ResultWrapper ) {
 391                         $res = $res->result;
 392                 }
 393
 394                 return $this->mysqlFieldName( $res, $n );
 395         }
 396
 397         /**
 398          * Get the name of the specified field in a result
 399          *
 400          * @param ResultWrapper|resource $res
 401          * @param int $n
 402          * @return string
 403          */
 404         abstract protected function mysqlFieldName( $res, $n );
 405
 406         /**
 407          * mysql_field_type() wrapper
 408          * @param ResultWrapper|resource $res
 409          * @param int $n
 410          * @return string
 411          */
 412         public function fieldType( $res, $n ) {
 413                 if ( $res instanceof ResultWrapper ) {
 414                         $res = $res->result;
 415                 }
 416
 417                 return $this->mysqlFieldType( $res, $n );
 418         }
 419
 420         /**
 421          * Get the type of the specified field in a result
 422          *
 423          * @param ResultWrapper|resource $res
 424          * @param int $n
 425          * @return string
 426          */
 427         abstract protected function mysqlFieldType( $res, $n );
 428
 429         /**
 430          * @param ResultWrapper|resource $res
 431          * @param int $row
 432          * @return bool
 433          */
 434         public function dataSeek( $res, $row ) {
 435                 if ( $res instanceof ResultWrapper ) {
 436                         $res = $res->result;
 437                 }
 438
 439                 return $this->mysqlDataSeek( $res, $row );
 440         }
 441
 442         /**
 443          * Move internal result pointer
 444          *
 445          * @param ResultWrapper|resource $res
 446          * @param int $row
 447          * @return bool
 448          */
 449         abstract protected function mysqlDataSeek( $res, $row );
 450
 451         /**
 452          * @return string
 453          */
 454         public function lastError() {
 455                 if ( $this->mConn ) {
 456                         # Even if it's non-zero, it can still be invalid
 457                         MediaWiki\suppressWarnings();
 458                         $error = $this->mysqlError( $this->mConn );
 459                         if ( !$error ) {
 460                                 $error = $this->mysqlError();
 461                         }
 462                         MediaWiki\restoreWarnings();
 463                 } else {
 464                         $error = $this->mysqlError();
 465                 }
 466                 if ( $error ) {
 467                         $error .= ' (' . $this->mServer . ')';
 468                 }
 469
 470                 return $error;
 471         }
 472
 473         /**
 474          * Returns the text of the error message from previous MySQL operation
 475          *
 476          * @param resource $conn Raw connection
 477          * @return string
 478          */
 479         abstract protected function mysqlError( $conn = null );
 480
 481         /**
 482          * @param string $table
 483          * @param array $uniqueIndexes
 484          * @param array $rows
 485          * @param string $fname
 486          * @return ResultWrapper
 487          */
 488         public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 489                 return $this->nativeReplace( $table, $rows, $fname );
 490         }
 491
 492         /**
 493          * Estimate rows in dataset
 494          * Returns estimated count, based on EXPLAIN output
 495          * Takes same arguments as Database::select()
 496          *
 497          * @param string|array $table
 498          * @param string|array $vars
 499          * @param string|array $conds
 500          * @param string $fname
 501          * @param string|array $options
 502          * @return bool|int
 503          */
 504         public function estimateRowCount( $table, $vars = '*', $conds = '',
 505                 $fname = __METHOD__, $options = []
 506         ) {
 507                 $options['EXPLAIN'] = true;
 508                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 509                 if ( $res === false ) {
 510                         return false;
 511                 }
 512                 if ( !$this->numRows( $res ) ) {
 513                         return 0;
 514                 }
 515
 516                 $rows = 1;
 517                 foreach ( $res as $plan ) {
 518                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 519                 }
 520
 521                 return (int)$rows;
 522         }
 523
 524         public function tableExists( $table, $fname = __METHOD__ ) {
 525                 $table = $this->tableName( $table, 'raw' );
 526                 if ( isset( $this->mSessionTempTables[$table] ) ) {
 527                         return true; // already known to exist and won't show in SHOW TABLES anyway
 528                 }
 529
 530                 $encLike = $this->buildLike( $table );
 531
 532                 return $this->query( "SHOW TABLES $encLike", $fname )->numRows() > 0;
 533         }
 534
 535         /**
 536          * @param string $table
 537          * @param string $field
 538          * @return bool|MySQLField
 539          */
 540         public function fieldInfo( $table, $field ) {
 541                 $table = $this->tableName( $table );
 542                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 543                 if ( !$res ) {
 544                         return false;
 545                 }
 546                 $n = $this->mysqlNumFields( $res->result );
 547                 for ( $i = 0; $i < $n; $i++ ) {
 548                         $meta = $this->mysqlFetchField( $res->result, $i );
 549                         if ( $field == $meta->name ) {
 550                                 return new MySQLField( $meta );
 551                         }
 552                 }
 553
 554                 return false;
 555         }
 556
 557         /**
 558          * Get column information from a result
 559          *
 560          * @param resource $res Raw result
 561          * @param int $n
 562          * @return stdClass
 563          */
 564         abstract protected function mysqlFetchField( $res, $n );
 565
 566         /**
 567          * Get information about an index into an object
 568          * Returns false if the index does not exist
 569          *
 570          * @param string $table
 571          * @param string $index
 572          * @param string $fname
 573          * @return bool|array|null False or null on failure
 574          */
 575         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 576                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 577                 # SHOW INDEX should work for 3.x and up:
 578                 # https://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 579                 $table = $this->tableName( $table );
 580                 $index = $this->indexName( $index );
 581
 582                 $sql = 'SHOW INDEX FROM ' . $table;
 583                 $res = $this->query( $sql, $fname );
 584
 585                 if ( !$res ) {
 586                         return null;
 587                 }
 588
 589                 $result = [];
 590
 591                 foreach ( $res as $row ) {
 592                         if ( $row->Key_name == $index ) {
 593                                 $result[] = $row;
 594                         }
 595                 }
 596
 597                 return empty( $result ) ? false : $result;
 598         }
 599
 600         /**
 601          * @param string $s
 602          * @return string
 603          */
 604         public function strencode( $s ) {
 605                 return $this->mysqlRealEscapeString( $s );
 606         }
 607
 608         /**
 609          * @param string $s
 610          * @return mixed
 611          */
 612         abstract protected function mysqlRealEscapeString( $s );
 613
 614         public function addQuotes( $s ) {
 615                 if ( is_bool( $s ) ) {
 616                         // Parent would transform to int, which does not play nice with MySQL type juggling.
 617                         // When searching for an int in a string column, the strings are cast to int, which
 618                         // means false would match any string not starting with a number.
 619                         $s = (string)(int)$s;
 620                 }
 621                 return parent::addQuotes( $s );
 622         }
 623
 624         /**
 625          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 626          *
 627          * @param string $s
 628          * @return string
 629          */
 630         public function addIdentifierQuotes( $s ) {
 631                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 632                 // Remove NUL bytes and escape backticks by doubling
 633                 return '`' . str_replace( [ "\0", '`' ], [ '', '``' ], $s ) . '`';
 634         }
 635
 636         /**
 637          * @param string $name
 638          * @return bool
 639          */
 640         public function isQuotedIdentifier( $name ) {
 641                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 642         }
 643
 644         public function getLag() {
 645                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 646                         return $this->getLagFromPtHeartbeat();
 647                 } else {
 648                         return $this->getLagFromSlaveStatus();
 649                 }
 650         }
 651
 652         /**
 653          * @return string
 654          */
 655         protected function getLagDetectionMethod() {
 656                 return $this->lagDetectionMethod;
 657         }
 658
 659         /**
 660          * @return bool|int
 661          */
 662         protected function getLagFromSlaveStatus() {
 663                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 664                 $row = $res ? $res->fetchObject() : false;
 665                 if ( $row && strval( $row->Seconds_Behind_Master ) !== '' ) {
 666                         return intval( $row->Seconds_Behind_Master );
 667                 }
 668
 669                 return false;
 670         }
 671
 672         /**
 673          * @return bool|float
 674          */
 675         protected function getLagFromPtHeartbeat() {
 676                 $options = $this->lagDetectionOptions;
 677
 678                 if ( isset( $options['conds'] ) ) {
 679                         // Best method for multi-DC setups: use logical channel names
 680                         $data = $this->getHeartbeatData( $options['conds'] );
 681                 } else {
 682                         // Standard method: use master server ID (works with stock pt-heartbeat)
 683                         $masterInfo = $this->getMasterServerInfo();
 684                         if ( !$masterInfo ) {
 685                                 $this->queryLogger->error(
 686                                         "Unable to query master of {db_server} for server ID",
 687                                         $this->getLogContext( [
 688                                                 'method' => __METHOD__
 689                                         ] )
 690                                 );
 691
 692                                 return false; // could not get master server ID
 693                         }
 694
 695                         $conds = [ 'server_id' => intval( $masterInfo['serverId'] ) ];
 696                         $data = $this->getHeartbeatData( $conds );
 697                 }
 698
 699                 list( $time, $nowUnix ) = $data;
 700                 if ( $time !== null ) {
 701                         // @time is in ISO format like "2015-09-25T16:48:10.000510"
 702                         $dateTime = new DateTime( $time, new DateTimeZone( 'UTC' ) );
 703                         $timeUnix = (int)$dateTime->format( 'U' ) + $dateTime->format( 'u' ) / 1e6;
 704
 705                         return max( $nowUnix - $timeUnix, 0.0 );
 706                 }
 707
 708                 $this->queryLogger->error(
 709                         "Unable to find pt-heartbeat row for {db_server}",
 710                         $this->getLogContext( [
 711                                 'method' => __METHOD__
 712                         ] )
 713                 );
 714
 715                 return false;
 716         }
 717
 718         protected function getMasterServerInfo() {
 719                 $cache = $this->srvCache;
 720                 $key = $cache->makeGlobalKey(
 721                         'mysql',
 722                         'master-info',
 723                         // Using one key for all cluster replica DBs is preferable
 724                         $this->getLBInfo( 'clusterMasterHost' ) ?: $this->getServer()
 725                 );
 726
 727                 return $cache->getWithSetCallback(
 728                         $key,
 729                         $cache::TTL_INDEFINITE,
 730                         function () use ( $cache, $key ) {
 731                                 // Get and leave a lock key in place for a short period
 732                                 if ( !$cache->lock( $key, 0, 10 ) ) {
 733                                         return false; // avoid master connection spike slams
 734                                 }
 735
 736                                 $conn = $this->getLazyMasterHandle();
 737                                 if ( !$conn ) {
 738                                         return false; // something is misconfigured
 739                                 }
 740
 741                                 // Connect to and query the master; catch errors to avoid outages
 742                                 try {
 743                                         $res = $conn->query( 'SELECT @@server_id AS id', __METHOD__ );
 744                                         $row = $res ? $res->fetchObject() : false;
 745                                         $id = $row ? (int)$row->id : 0;
 746                                 } catch ( DBError $e ) {
 747                                         $id = 0;
 748                                 }
 749
 750                                 // Cache the ID if it was retrieved
 751                                 return $id ? [ 'serverId' => $id, 'asOf' => time() ] : false;
 752                         }
 753                 );
 754         }
 755
 756         /**
 757          * @param array $conds WHERE clause conditions to find a row
 758          * @return array (heartbeat `ts` column value or null, UNIX timestamp) for the newest beat
 759          * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html
 760          */
 761         protected function getHeartbeatData( array $conds ) {
 762                 // Do not bother starting implicit transactions here
 763                 $this->clearFlag( self::DBO_TRX, self::REMEMBER_PRIOR );
 764                 try {
 765                         $whereSQL = $this->makeList( $conds, self::LIST_AND );
 766                         // Use ORDER BY for channel based queries since that field might not be UNIQUE.
 767                         // Note: this would use "TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6))" but the
 768                         // percision field is not supported in MySQL <= 5.5.
 769                         $res = $this->query(
 770                                 "SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1"
 771                         );
 772                         $row = $res ? $res->fetchObject() : false;
 773                 } finally {
 774                         $this->restoreFlags();
 775                 }
 776
 777                 return [ $row ? $row->ts : null, microtime( true ) ];
 778         }
 779
 780         protected function getApproximateLagStatus() {
 781                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 782                         // Disable caching since this is fast enough and we don't wan't
 783                         // to be *too* pessimistic by having both the cache TTL and the
 784                         // pt-heartbeat interval count as lag in getSessionLagStatus()
 785                         return parent::getApproximateLagStatus();
 786                 }
 787
 788                 $key = $this->srvCache->makeGlobalKey( 'mysql-lag', $this->getServer() );
 789                 $approxLag = $this->srvCache->get( $key );
 790                 if ( !$approxLag ) {
 791                         $approxLag = parent::getApproximateLagStatus();
 792                         $this->srvCache->set( $key, $approxLag, 1 );
 793                 }
 794
 795                 return $approxLag;
 796         }
 797
 798         public function masterPosWait( DBMasterPos $pos, $timeout ) {
 799                 if ( !( $pos instanceof MySQLMasterPos ) ) {
 800                         throw new InvalidArgumentException( "Position not an instance of MySQLMasterPos" );
 801                 }
 802
 803                 if ( $this->getLBInfo( 'is static' ) === true ) {
 804                         return 0; // this is a copy of a read-only dataset with no master DB
 805                 } elseif ( $this->lastKnownReplicaPos && $this->lastKnownReplicaPos->hasReached( $pos ) ) {
 806                         return 0; // already reached this point for sure
 807                 }
 808
 809                 // Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 810                 if ( $this->useGTIDs && $pos->gtids ) {
 811                         // Wait on the GTID set (MariaDB only)
 812                         $gtidArg = $this->addQuotes( implode( ',', $pos->gtids ) );
 813                         $res = $this->doQuery( "SELECT MASTER_GTID_WAIT($gtidArg, $timeout)" );
 814                 } else {
 815                         // Wait on the binlog coordinates
 816                         $encFile = $this->addQuotes( $pos->file );
 817                         $encPos = intval( $pos->pos );
 818                         $res = $this->doQuery( "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)" );
 819                 }
 820
 821                 $row = $res ? $this->fetchRow( $res ) : false;
 822                 if ( !$row ) {
 823                         throw new DBExpectedError( $this, "Failed to query MASTER_POS_WAIT()" );
 824                 }
 825
 826                 // Result can be NULL (error), -1 (timeout), or 0+ per the MySQL manual
 827                 $status = ( $row[0] !== null ) ? intval( $row[0] ) : null;
 828                 if ( $status === null ) {
 829                         // T126436: jobs programmed to wait on master positions might be referencing binlogs
 830                         // with an old master hostname. Such calls make MASTER_POS_WAIT() return null. Try
 831                         // to detect this and treat the replica DB as having reached the position; a proper master
 832                         // switchover already requires that the new master be caught up before the switch.
 833                         $replicationPos = $this->getReplicaPos();
 834                         if ( $replicationPos && !$replicationPos->channelsMatch( $pos ) ) {
 835                                 $this->lastKnownReplicaPos = $replicationPos;
 836                                 $status = 0;
 837                         }
 838                 } elseif ( $status >= 0 ) {
 839                         // Remember that this position was reached to save queries next time
 840                         $this->lastKnownReplicaPos = $pos;
 841                 }
 842
 843                 return $status;
 844         }
 845
 846         /**
 847          * Get the position of the master from SHOW SLAVE STATUS
 848          *
 849          * @return MySQLMasterPos|bool
 850          */
 851         public function getReplicaPos() {
 852                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 853                 $row = $this->fetchObject( $res );
 854
 855                 if ( $row ) {
 856                         $pos = isset( $row->Exec_master_log_pos )
 857                                 ? $row->Exec_master_log_pos
 858                                 : $row->Exec_Master_Log_Pos;
 859                         // Also fetch the last-applied GTID set (MariaDB)
 860                         if ( $this->useGTIDs ) {
 861                                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'gtid_slave_pos'", __METHOD__ );
 862                                 $gtidRow = $this->fetchObject( $res );
 863                                 $gtidSet = $gtidRow ? $gtidRow->Value : '';
 864                         } else {
 865                                 $gtidSet = '';
 866                         }
 867
 868                         return new MySQLMasterPos( $row->Relay_Master_Log_File, $pos, $gtidSet );
 869                 } else {
 870                         return false;
 871                 }
 872         }
 873
 874         /**
 875          * Get the position of the master from SHOW MASTER STATUS
 876          *
 877          * @return MySQLMasterPos|bool
 878          */
 879         public function getMasterPos() {
 880                 $res = $this->query( 'SHOW MASTER STATUS', __METHOD__ );
 881                 $row = $this->fetchObject( $res );
 882
 883                 if ( $row ) {
 884                         // Also fetch the last-written GTID set (MariaDB)
 885                         if ( $this->useGTIDs ) {
 886                                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'gtid_binlog_pos'", __METHOD__ );
 887                                 $gtidRow = $this->fetchObject( $res );
 888                                 $gtidSet = $gtidRow ? $gtidRow->Value : '';
 889                         } else {
 890                                 $gtidSet = '';
 891                         }
 892
 893                         return new MySQLMasterPos( $row->File, $row->Position, $gtidSet );
 894                 } else {
 895                         return false;
 896                 }
 897         }
 898
 899         public function serverIsReadOnly() {
 900                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'read_only'", __METHOD__ );
 901                 $row = $this->fetchObject( $res );
 902
 903                 return $row ? ( strtolower( $row->Value ) === 'on' ) : false;
 904         }
 905
 906         /**
 907          * @param string $index
 908          * @return string
 909          */
 910         function useIndexClause( $index ) {
 911                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
 912         }
 913
 914         /**
 915          * @param string $index
 916          * @return string
 917          */
 918         function ignoreIndexClause( $index ) {
 919                 return "IGNORE INDEX (" . $this->indexName( $index ) . ")";
 920         }
 921
 922         /**
 923          * @return string
 924          */
 925         function lowPriorityOption() {
 926                 return 'LOW_PRIORITY';
 927         }
 928
 929         /**
 930          * @return string
 931          */
 932         public function getSoftwareLink() {
 933                 // MariaDB includes its name in its version string; this is how MariaDB's version of
 934                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
 935                 // in libmysql/libmysql.c).
 936                 $version = $this->getServerVersion();
 937                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
 938                         return '[{{int:version-db-mariadb-url}} MariaDB]';
 939                 }
 940
 941                 // Percona Server's version suffix is not very distinctive, and @@version_comment
 942                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
 943                 // (Even Percona's version of mysql doesn't try to make the distinction.)
 944                 return '[{{int:version-db-mysql-url}} MySQL]';
 945         }
 946
 947         /**
 948          * @return string
 949          */
 950         public function getServerVersion() {
 951                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
 952                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
 953                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
 954                 if ( $this->serverVersion === null ) {
 955                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
 956                 }
 957                 return $this->serverVersion;
 958         }
 959
 960         /**
 961          * @param array $options
 962          */
 963         public function setSessionOptions( array $options ) {
 964                 if ( isset( $options['connTimeout'] ) ) {
 965                         $timeout = (int)$options['connTimeout'];
 966                         $this->query( "SET net_read_timeout=$timeout" );
 967                         $this->query( "SET net_write_timeout=$timeout" );
 968                 }
 969         }
 970
 971         /**
 972          * @param string $sql
 973          * @param string $newLine
 974          * @return bool
 975          */
 976         public function streamStatementEnd( &$sql, &$newLine ) {
 977                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
 978                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
 979                         $this->delimiter = $m[1];
 980                         $newLine = '';
 981                 }
 982
 983                 return parent::streamStatementEnd( $sql, $newLine );
 984         }
 985
 986         /**
 987          * Check to see if a named lock is available. This is non-blocking.
 988          *
 989          * @param string $lockName Name of lock to poll
 990          * @param string $method Name of method calling us
 991          * @return bool
 992          * @since 1.20
 993          */
 994         public function lockIsFree( $lockName, $method ) {
 995                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
 996                 $result = $this->query( "SELECT IS_FREE_LOCK($encName) AS lockstatus", $method );
 997                 $row = $this->fetchObject( $result );
 998
 999                 return ( $row->lockstatus == 1 );
1000         }
1001
1002         /**
1003          * @param string $lockName
1004          * @param string $method
1005          * @param int $timeout
1006          * @return bool
1007          */
1008         public function lock( $lockName, $method, $timeout = 5 ) {
1009                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1010                 $result = $this->query( "SELECT GET_LOCK($encName, $timeout) AS lockstatus", $method );
1011                 $row = $this->fetchObject( $result );
1012
1013                 if ( $row->lockstatus == 1 ) {
1014                         parent::lock( $lockName, $method, $timeout ); // record
1015                         return true;
1016                 }
1017
1018                 $this->queryLogger->warning( __METHOD__ . " failed to acquire lock '$lockName'\n" );
1019
1020                 return false;
1021         }
1022
1023         /**
1024          * FROM MYSQL DOCS:
1025          * https://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
1026          * @param string $lockName
1027          * @param string $method
1028          * @return bool
1029          */
1030         public function unlock( $lockName, $method ) {
1031                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1032                 $result = $this->query( "SELECT RELEASE_LOCK($encName) as lockstatus", $method );
1033                 $row = $this->fetchObject( $result );
1034
1035                 if ( $row->lockstatus == 1 ) {
1036                         parent::unlock( $lockName, $method ); // record
1037                         return true;
1038                 }
1039
1040                 $this->queryLogger->warning( __METHOD__ . " failed to release lock '$lockName'\n" );
1041
1042                 return false;
1043         }
1044
1045         private function makeLockName( $lockName ) {
1046                 // https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
1047                 // Newer version enforce a 64 char length limit.
1048                 return ( strlen( $lockName ) > 64 ) ? sha1( $lockName ) : $lockName;
1049         }
1050
1051         public function namedLocksEnqueue() {
1052                 return true;
1053         }
1054
1055         /**
1056          * @param array $read
1057          * @param array $write
1058          * @param string $method
1059          * @param bool $lowPriority
1060          * @return bool
1061          */
1062         public function lockTables( $read, $write, $method, $lowPriority = true ) {
1063                 $items = [];
1064
1065                 foreach ( $write as $table ) {
1066                         $tbl = $this->tableName( $table ) .
1067                                 ( $lowPriority ? ' LOW_PRIORITY' : '' ) .
1068                                 ' WRITE';
1069                         $items[] = $tbl;
1070                 }
1071                 foreach ( $read as $table ) {
1072                         $items[] = $this->tableName( $table ) . ' READ';
1073                 }
1074                 $sql = "LOCK TABLES " . implode( ',', $items );
1075                 $this->query( $sql, $method );
1076
1077                 return true;
1078         }
1079
1080         /**
1081          * @param string $method
1082          * @return bool
1083          */
1084         public function unlockTables( $method ) {
1085                 $this->query( "UNLOCK TABLES", $method );
1086
1087                 return true;
1088         }
1089
1090         /**
1091          * @param bool $value
1092          */
1093         public function setBigSelects( $value = true ) {
1094                 if ( $value === 'default' ) {
1095                         if ( $this->mDefaultBigSelects === null ) {
1096                                 # Function hasn't been called before so it must already be set to the default
1097                                 return;
1098                         } else {
1099                                 $value = $this->mDefaultBigSelects;
1100                         }
1101                 } elseif ( $this->mDefaultBigSelects === null ) {
1102                         $this->mDefaultBigSelects =
1103                                 (bool)$this->selectField( false, '@@sql_big_selects', '', __METHOD__ );
1104                 }
1105                 $encValue = $value ? '1' : '0';
1106                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
1107         }
1108
1109         /**
1110          * DELETE where the condition is a join. MySql uses multi-table deletes.
1111          * @param string $delTable
1112          * @param string $joinTable
1113          * @param string $delVar
1114          * @param string $joinVar
1115          * @param array|string $conds
1116          * @param bool|string $fname
1117          * @throws DBUnexpectedError
1118          * @return bool|ResultWrapper
1119          */
1120         public function deleteJoin(
1121                 $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__
1122         ) {
1123                 if ( !$conds ) {
1124                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with empty $conds' );
1125                 }
1126
1127                 $delTable = $this->tableName( $delTable );
1128                 $joinTable = $this->tableName( $joinTable );
1129                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1130
1131                 if ( $conds != '*' ) {
1132                         $sql .= ' AND ' . $this->makeList( $conds, self::LIST_AND );
1133                 }
1134
1135                 return $this->query( $sql, $fname );
1136         }
1137
1138         /**
1139          * @param string $table
1140          * @param array $rows
1141          * @param array $uniqueIndexes
1142          * @param array $set
1143          * @param string $fname
1144          * @return bool
1145          */
1146         public function upsert( $table, array $rows, array $uniqueIndexes,
1147                 array $set, $fname = __METHOD__
1148         ) {
1149                 if ( !count( $rows ) ) {
1150                         return true; // nothing to do
1151                 }
1152
1153                 if ( !is_array( reset( $rows ) ) ) {
1154                         $rows = [ $rows ];
1155                 }
1156
1157                 $table = $this->tableName( $table );
1158                 $columns = array_keys( $rows[0] );
1159
1160                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
1161                 $rowTuples = [];
1162                 foreach ( $rows as $row ) {
1163                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
1164                 }
1165                 $sql .= implode( ',', $rowTuples );
1166                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, self::LIST_SET );
1167
1168                 return (bool)$this->query( $sql, $fname );
1169         }
1170
1171         /**
1172          * Determines how long the server has been up
1173          *
1174          * @return int
1175          */
1176         public function getServerUptime() {
1177                 $vars = $this->getMysqlStatus( 'Uptime' );
1178
1179                 return (int)$vars['Uptime'];
1180         }
1181
1182         /**
1183          * Determines if the last failure was due to a deadlock
1184          *
1185          * @return bool
1186          */
1187         public function wasDeadlock() {
1188                 return $this->lastErrno() == 1213;
1189         }
1190
1191         /**
1192          * Determines if the last failure was due to a lock timeout
1193          *
1194          * @return bool
1195          */
1196         public function wasLockTimeout() {
1197                 return $this->lastErrno() == 1205;
1198         }
1199
1200         public function wasErrorReissuable() {
1201                 return $this->lastErrno() == 2013 || $this->lastErrno() == 2006;
1202         }
1203
1204         /**
1205          * Determines if the last failure was due to the database being read-only.
1206          *
1207          * @return bool
1208          */
1209         public function wasReadOnlyError() {
1210                 return $this->lastErrno() == 1223 ||
1211                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1212         }
1213
1214         public function wasConnectionError( $errno ) {
1215                 return $errno == 2013 || $errno == 2006;
1216         }
1217
1218         /**
1219          * @param string $oldName
1220          * @param string $newName
1221          * @param bool $temporary
1222          * @param string $fname
1223          * @return bool
1224          */
1225         public function duplicateTableStructure(
1226                 $oldName, $newName, $temporary = false, $fname = __METHOD__
1227         ) {
1228                 $tmp = $temporary ? 'TEMPORARY ' : '';
1229                 $newName = $this->addIdentifierQuotes( $newName );
1230                 $oldName = $this->addIdentifierQuotes( $oldName );
1231                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1232
1233                 return $this->query( $query, $fname );
1234         }
1235
1236         /**
1237          * List all tables on the database
1238          *
1239          * @param string $prefix Only show tables with this prefix, e.g. mw_
1240          * @param string $fname Calling function name
1241          * @return array
1242          */
1243         public function listTables( $prefix = null, $fname = __METHOD__ ) {
1244                 $result = $this->query( "SHOW TABLES", $fname );
1245
1246                 $endArray = [];
1247
1248                 foreach ( $result as $table ) {
1249                         $vars = get_object_vars( $table );
1250                         $table = array_pop( $vars );
1251
1252                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1253                                 $endArray[] = $table;
1254                         }
1255                 }
1256
1257                 return $endArray;
1258         }
1259
1260         /**
1261          * @param string $tableName
1262          * @param string $fName
1263          * @return bool|ResultWrapper
1264          */
1265         public function dropTable( $tableName, $fName = __METHOD__ ) {
1266                 if ( !$this->tableExists( $tableName, $fName ) ) {
1267                         return false;
1268                 }
1269
1270                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1271         }
1272
1273         /**
1274          * Get status information from SHOW STATUS in an associative array
1275          *
1276          * @param string $which
1277          * @return array
1278          */
1279         private function getMysqlStatus( $which = "%" ) {
1280                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1281                 $status = [];
1282
1283                 foreach ( $res as $row ) {
1284                         $status[$row->Variable_name] = $row->Value;
1285                 }
1286
1287                 return $status;
1288         }
1289
1290         /**
1291          * Lists VIEWs in the database
1292          *
1293          * @param string $prefix Only show VIEWs with this prefix, eg.
1294          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1295          * @param string $fname Name of calling function
1296          * @return array
1297          * @since 1.22
1298          */
1299         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1300                 // The name of the column containing the name of the VIEW
1301                 $propertyName = 'Tables_in_' . $this->mDBname;
1302
1303                 // Query for the VIEWS
1304                 $res = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1305                 $allViews = [];
1306                 foreach ( $res as $row ) {
1307                         array_push( $allViews, $row->$propertyName );
1308                 }
1309
1310                 if ( is_null( $prefix ) || $prefix === '' ) {
1311                         return $allViews;
1312                 }
1313
1314                 $filteredViews = [];
1315                 foreach ( $allViews as $viewName ) {
1316                         // Does the name of this VIEW start with the table-prefix?
1317                         if ( strpos( $viewName, $prefix ) === 0 ) {
1318                                 array_push( $filteredViews, $viewName );
1319                         }
1320                 }
1321
1322                 return $filteredViews;
1323         }
1324
1325         /**
1326          * Differentiates between a TABLE and a VIEW.
1327          *
1328          * @param string $name Name of the TABLE/VIEW to test
1329          * @param string $prefix
1330          * @return bool
1331          * @since 1.22
1332          */
1333         public function isView( $name, $prefix = null ) {
1334                 return in_array( $name, $this->listViews( $prefix ) );
1335         }
1336 }