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 namespace Wikimedia\Rdbms;
  24
  25 use DateTime;
  26 use DateTimeZone;
  27 use Wikimedia;
  28 use InvalidArgumentException;
  29 use Exception;
  30 use stdClass;
  31
  32 /**
  33  * Database abstraction object for MySQL.
  34  * Defines methods independent on used MySQL extension.
  35  *
  36  * @ingroup Database
  37  * @since 1.22
  38  * @see Database
  39  */
  40 abstract class DatabaseMysqlBase extends Database {
  41         /** @var MysqlMasterPos */
  42         protected $lastKnownReplicaPos;
  43         /** @var string Method to detect replica DB lag */
  44         protected $lagDetectionMethod;
  45         /** @var array Method to detect replica DB lag */
  46         protected $lagDetectionOptions = [];
  47         /** @var bool bool Whether to use GTID methods */
  48         protected $useGTIDs = false;
  49         /** @var string|null */
  50         protected $sslKeyPath;
  51         /** @var string|null */
  52         protected $sslCertPath;
  53         /** @var string|null */
  54         protected $sslCAFile;
  55         /** @var string|null */
  56         protected $sslCAPath;
  57         /** @var string[]|null */
  58         protected $sslCiphers;
  59         /** @var string sql_mode value to send on connection */
  60         protected $sqlMode;
  61         /** @var bool Use experimental UTF-8 transmission encoding */
  62         protected $utf8Mode;
  63         /** @var bool|null */
  64         protected $defaultBigSelects = null;
  65
  66         /** @var string|null */
  67         private $serverVersion = null;
  68         /** @var bool|null */
  69         private $insertSelectIsSafe = null;
  70         /** @var stdClass|null */
  71         private $replicationInfoRow = null;
  72
  73         // Cache getServerId() for 24 hours
  74         const SERVER_ID_CACHE_TTL = 86400;
  75
  76         /** @var float Warn if lag estimates are made for transactions older than this many seconds */
  77         const LAG_STALE_WARN_THRESHOLD = 0.100;
  78
  79         /**
  80          * Additional $params include:
  81          *   - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat).
  82          *       pt-heartbeat assumes the table is at heartbeat.heartbeat
  83          *       and uses UTC timestamps in the heartbeat.ts column.
  84          *       (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html)
  85          *   - lagDetectionOptions : if using pt-heartbeat, this can be set to an array map to change
  86          *       the default behavior. Normally, the heartbeat row with the server
  87          *       ID of this server's master will be used. Set the "conds" field to
  88          *       override the query conditions, e.g. ['shard' => 's1'].
  89          *   - useGTIDs : use GTID methods like MASTER_GTID_WAIT() when possible.
  90          *   - insertSelectIsSafe : force that native INSERT SELECT is or is not safe [default: null]
  91          *   - sslKeyPath : path to key file [default: null]
  92          *   - sslCertPath : path to certificate file [default: null]
  93          *   - sslCAFile: path to a single certificate authority PEM file [default: null]
  94          *   - sslCAPath : parth to certificate authority PEM directory [default: null]
  95          *   - sslCiphers : array list of allowable ciphers [default: null]
  96          * @param array $params
  97          */
  98         function __construct( array $params ) {
  99                 $this->lagDetectionMethod = $params['lagDetectionMethod'] ?? 'Seconds_Behind_Master';
 100                 $this->lagDetectionOptions = $params['lagDetectionOptions'] ?? [];
 101                 $this->useGTIDs = !empty( $params['useGTIDs' ] );
 102                 foreach ( [ 'KeyPath', 'CertPath', 'CAFile', 'CAPath', 'Ciphers' ] as $name ) {
 103                         $var = "ssl{$name}";
 104                         if ( isset( $params[$var] ) ) {
 105                                 $this->$var = $params[$var];
 106                         }
 107                 }
 108                 $this->sqlMode = $params['sqlMode'] ?? '';
 109                 $this->utf8Mode = !empty( $params['utf8Mode'] );
 110                 $this->insertSelectIsSafe = isset( $params['insertSelectIsSafe'] )
 111                         ? (bool)$params['insertSelectIsSafe'] : null;
 112
 113                 parent::__construct( $params );
 114         }
 115
 116         /**
 117          * @return string
 118          */
 119         public function getType() {
 120                 return 'mysql';
 121         }
 122
 123         protected function open( $server, $user, $password, $dbName, $schema, $tablePrefix ) {
 124                 # Close/unset connection handle
 125                 $this->close();
 126
 127                 $this->server = $server;
 128                 $this->user = $user;
 129                 $this->password = $password;
 130
 131                 $this->installErrorHandler();
 132                 try {
 133                         $this->conn = $this->mysqlConnect( $this->server, $dbName );
 134                 } catch ( Exception $ex ) {
 135                         $this->restoreErrorHandler();
 136                         throw $ex;
 137                 }
 138                 $error = $this->restoreErrorHandler();
 139
 140                 # Always log connection errors
 141                 if ( !$this->conn ) {
 142                         $error = $error ?: $this->lastError();
 143                         $this->connLogger->error(
 144                                 "Error connecting to {db_server}: {error}",
 145                                 $this->getLogContext( [
 146                                         'method' => __METHOD__,
 147                                         'error' => $error,
 148                                 ] )
 149                         );
 150                         $this->connLogger->debug( "DB connection error\n" .
 151                                 "Server: $server, User: $user, Password: " .
 152                                 substr( $password, 0, 3 ) . "..., error: " . $error . "\n" );
 153
 154                         throw new DBConnectionError( $this, $error );
 155                 }
 156
 157                 if ( strlen( $dbName ) ) {
 158                         $this->selectDomain( new DatabaseDomain( $dbName, null, $tablePrefix ) );
 159                 } else {
 160                         $this->currentDomain = new DatabaseDomain( null, null, $tablePrefix );
 161                 }
 162
 163                 // Tell the server what we're communicating with
 164                 if ( !$this->connectInitCharset() ) {
 165                         $error = $this->lastError();
 166                         $this->queryLogger->error(
 167                                 "Error setting character set: {error}",
 168                                 $this->getLogContext( [
 169                                         'method' => __METHOD__,
 170                                         'error' => $this->lastError(),
 171                                 ] )
 172                         );
 173                         throw new DBConnectionError( $this, "Error setting character set: $error" );
 174                 }
 175
 176                 // Abstract over any insane MySQL defaults
 177                 $set = [ 'group_concat_max_len = 262144' ];
 178                 // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 179                 if ( is_string( $this->sqlMode ) ) {
 180                         $set[] = 'sql_mode = ' . $this->addQuotes( $this->sqlMode );
 181                 }
 182                 // Set any custom settings defined by site config
 183                 // (e.g. https://dev.mysql.com/doc/refman/4.1/en/innodb-parameters.html)
 184                 foreach ( $this->sessionVars as $var => $val ) {
 185                         // Escape strings but not numbers to avoid MySQL complaining
 186                         if ( !is_int( $val ) && !is_float( $val ) ) {
 187                                 $val = $this->addQuotes( $val );
 188                         }
 189                         $set[] = $this->addIdentifierQuotes( $var ) . ' = ' . $val;
 190                 }
 191
 192                 if ( $set ) {
 193                         // Use doQuery() to avoid opening implicit transactions (DBO_TRX)
 194                         $success = $this->doQuery( 'SET ' . implode( ', ', $set ) );
 195                         if ( !$success ) {
 196                                 $error = $this->lastError();
 197                                 $this->queryLogger->error(
 198                                         'Error setting MySQL variables on server {db_server}: {error}',
 199                                         $this->getLogContext( [
 200                                                 'method' => __METHOD__,
 201                                                 'error' => $error,
 202                                         ] )
 203                                 );
 204                                 throw new DBConnectionError( $this, "Error setting MySQL variables: $error" );
 205                         }
 206                 }
 207
 208                 $this->opened = true;
 209
 210                 return true;
 211         }
 212
 213         /**
 214          * Set the character set information right after connection
 215          * @return bool
 216          */
 217         protected function connectInitCharset() {
 218                 if ( $this->utf8Mode ) {
 219                         // Tell the server we're communicating with it in UTF-8.
 220                         // This may engage various charset conversions.
 221                         return $this->mysqlSetCharset( 'utf8' );
 222                 } else {
 223                         return $this->mysqlSetCharset( 'binary' );
 224                 }
 225         }
 226
 227         /**
 228          * Open a connection to a MySQL server
 229          *
 230          * @param string $realServer
 231          * @param string|null $dbName
 232          * @return mixed Raw connection
 233          * @throws DBConnectionError
 234          */
 235         abstract protected function mysqlConnect( $realServer, $dbName );
 236
 237         /**
 238          * Set the character set of the MySQL link
 239          *
 240          * @param string $charset
 241          * @return bool
 242          */
 243         abstract protected function mysqlSetCharset( $charset );
 244
 245         /**
 246          * @param ResultWrapper|resource $res
 247          * @throws DBUnexpectedError
 248          */
 249         public function freeResult( $res ) {
 250                 if ( $res instanceof ResultWrapper ) {
 251                         $res = $res->result;
 252                 }
 253                 Wikimedia\suppressWarnings();
 254                 $ok = $this->mysqlFreeResult( $res );
 255                 Wikimedia\restoreWarnings();
 256                 if ( !$ok ) {
 257                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 258                 }
 259         }
 260
 261         /**
 262          * Free result memory
 263          *
 264          * @param resource $res Raw result
 265          * @return bool
 266          */
 267         abstract protected function mysqlFreeResult( $res );
 268
 269         /**
 270          * @param ResultWrapper|resource $res
 271          * @return stdClass|bool
 272          * @throws DBUnexpectedError
 273          */
 274         public function fetchObject( $res ) {
 275                 if ( $res instanceof ResultWrapper ) {
 276                         $res = $res->result;
 277                 }
 278                 Wikimedia\suppressWarnings();
 279                 $row = $this->mysqlFetchObject( $res );
 280                 Wikimedia\restoreWarnings();
 281
 282                 $errno = $this->lastErrno();
 283                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 284                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 285                 // these are the only errors mysql_fetch_object can cause.
 286                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 287                 if ( $errno == 2000 || $errno == 2013 ) {
 288                         throw new DBUnexpectedError(
 289                                 $this,
 290                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 291                         );
 292                 }
 293
 294                 return $row;
 295         }
 296
 297         /**
 298          * Fetch a result row as an object
 299          *
 300          * @param resource $res Raw result
 301          * @return stdClass
 302          */
 303         abstract protected function mysqlFetchObject( $res );
 304
 305         /**
 306          * @param IResultWrapper|resource $res
 307          * @return array|bool
 308          * @throws DBUnexpectedError
 309          */
 310         public function fetchRow( $res ) {
 311                 if ( $res instanceof ResultWrapper ) {
 312                         $res = $res->result;
 313                 }
 314                 Wikimedia\suppressWarnings();
 315                 $row = $this->mysqlFetchArray( $res );
 316                 Wikimedia\restoreWarnings();
 317
 318                 $errno = $this->lastErrno();
 319                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 320                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 321                 // these are the only errors mysql_fetch_array can cause.
 322                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 323                 if ( $errno == 2000 || $errno == 2013 ) {
 324                         throw new DBUnexpectedError(
 325                                 $this,
 326                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 327                         );
 328                 }
 329
 330                 return $row;
 331         }
 332
 333         /**
 334          * Fetch a result row as an associative and numeric array
 335          *
 336          * @param resource $res Raw result
 337          * @return array
 338          */
 339         abstract protected function mysqlFetchArray( $res );
 340
 341         /**
 342          * @throws DBUnexpectedError
 343          * @param ResultWrapper|resource $res
 344          * @return int
 345          */
 346         function numRows( $res ) {
 347                 if ( $res instanceof ResultWrapper ) {
 348                         $res = $res->result;
 349                 }
 350                 Wikimedia\suppressWarnings();
 351                 $n = !is_bool( $res ) ? $this->mysqlNumRows( $res ) : 0;
 352                 Wikimedia\restoreWarnings();
 353
 354                 // Unfortunately, mysql_num_rows does not reset the last errno.
 355                 // We are not checking for any errors here, since
 356                 // there are no errors mysql_num_rows can cause.
 357                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 358                 // See https://phabricator.wikimedia.org/T44430
 359                 return $n;
 360         }
 361
 362         /**
 363          * Get number of rows in result
 364          *
 365          * @param resource $res Raw result
 366          * @return int
 367          */
 368         abstract protected function mysqlNumRows( $res );
 369
 370         /**
 371          * @param ResultWrapper|resource $res
 372          * @return int
 373          */
 374         public function numFields( $res ) {
 375                 if ( $res instanceof ResultWrapper ) {
 376                         $res = $res->result;
 377                 }
 378
 379                 return $this->mysqlNumFields( $res );
 380         }
 381
 382         /**
 383          * Get number of fields in result
 384          *
 385          * @param resource $res Raw result
 386          * @return int
 387          */
 388         abstract protected function mysqlNumFields( $res );
 389
 390         /**
 391          * @param ResultWrapper|resource $res
 392          * @param int $n
 393          * @return string
 394          */
 395         public function fieldName( $res, $n ) {
 396                 if ( $res instanceof ResultWrapper ) {
 397                         $res = $res->result;
 398                 }
 399
 400                 return $this->mysqlFieldName( $res, $n );
 401         }
 402
 403         /**
 404          * Get the name of the specified field in a result
 405          *
 406          * @param ResultWrapper|resource $res
 407          * @param int $n
 408          * @return string
 409          */
 410         abstract protected function mysqlFieldName( $res, $n );
 411
 412         /**
 413          * mysql_field_type() wrapper
 414          * @param ResultWrapper|resource $res
 415          * @param int $n
 416          * @return string
 417          */
 418         public function fieldType( $res, $n ) {
 419                 if ( $res instanceof ResultWrapper ) {
 420                         $res = $res->result;
 421                 }
 422
 423                 return $this->mysqlFieldType( $res, $n );
 424         }
 425
 426         /**
 427          * Get the type of the specified field in a result
 428          *
 429          * @param ResultWrapper|resource $res
 430          * @param int $n
 431          * @return string
 432          */
 433         abstract protected function mysqlFieldType( $res, $n );
 434
 435         /**
 436          * @param ResultWrapper|resource $res
 437          * @param int $row
 438          * @return bool
 439          */
 440         public function dataSeek( $res, $row ) {
 441                 if ( $res instanceof ResultWrapper ) {
 442                         $res = $res->result;
 443                 }
 444
 445                 return $this->mysqlDataSeek( $res, $row );
 446         }
 447
 448         /**
 449          * Move internal result pointer
 450          *
 451          * @param ResultWrapper|resource $res
 452          * @param int $row
 453          * @return bool
 454          */
 455         abstract protected function mysqlDataSeek( $res, $row );
 456
 457         /**
 458          * @return string
 459          */
 460         public function lastError() {
 461                 if ( $this->conn ) {
 462                         # Even if it's non-zero, it can still be invalid
 463                         Wikimedia\suppressWarnings();
 464                         $error = $this->mysqlError( $this->conn );
 465                         if ( !$error ) {
 466                                 $error = $this->mysqlError();
 467                         }
 468                         Wikimedia\restoreWarnings();
 469                 } else {
 470                         $error = $this->mysqlError();
 471                 }
 472                 if ( $error ) {
 473                         $error .= ' (' . $this->server . ')';
 474                 }
 475
 476                 return $error;
 477         }
 478
 479         /**
 480          * Returns the text of the error message from previous MySQL operation
 481          *
 482          * @param resource|null $conn Raw connection
 483          * @return string
 484          */
 485         abstract protected function mysqlError( $conn = null );
 486
 487         protected function wasQueryTimeout( $error, $errno ) {
 488                 return $errno == 2062;
 489         }
 490
 491         /**
 492          * @param string $table
 493          * @param array $uniqueIndexes
 494          * @param array $rows
 495          * @param string $fname
 496          */
 497         public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 498                 $this->nativeReplace( $table, $rows, $fname );
 499         }
 500
 501         protected function isInsertSelectSafe( array $insertOptions, array $selectOptions ) {
 502                 $row = $this->getReplicationSafetyInfo();
 503                 // For row-based-replication, the resulting changes will be relayed, not the query
 504                 if ( $row->binlog_format === 'ROW' ) {
 505                         return true;
 506                 }
 507                 // LIMIT requires ORDER BY on a unique key or it is non-deterministic
 508                 if ( isset( $selectOptions['LIMIT'] ) ) {
 509                         return false;
 510                 }
 511                 // In MySQL, an INSERT SELECT is only replication safe with row-based
 512                 // replication or if innodb_autoinc_lock_mode is 0. When those
 513                 // conditions aren't met, use non-native mode.
 514                 // While we could try to determine if the insert is safe anyway by
 515                 // checking if the target table has an auto-increment column that
 516                 // isn't set in $varMap, that seems unlikely to be worth the extra
 517                 // complexity.
 518                 return (
 519                         in_array( 'NO_AUTO_COLUMNS', $insertOptions ) ||
 520                         (int)$row->innodb_autoinc_lock_mode === 0
 521                 );
 522         }
 523
 524         /**
 525          * @return stdClass Process cached row
 526          */
 527         protected function getReplicationSafetyInfo() {
 528                 if ( $this->replicationInfoRow === null ) {
 529                         $this->replicationInfoRow = $this->selectRow(
 530                                 false,
 531                                 [
 532                                         'innodb_autoinc_lock_mode' => '@@innodb_autoinc_lock_mode',
 533                                         'binlog_format' => '@@binlog_format',
 534                                 ],
 535                                 [],
 536                                 __METHOD__
 537                         );
 538                 }
 539
 540                 return $this->replicationInfoRow;
 541         }
 542
 543         /**
 544          * Estimate rows in dataset
 545          * Returns estimated count, based on EXPLAIN output
 546          * Takes same arguments as Database::select()
 547          *
 548          * @param string|array $table
 549          * @param string|array $var
 550          * @param string|array $conds
 551          * @param string $fname
 552          * @param string|array $options
 553          * @param array $join_conds
 554          * @return bool|int
 555          */
 556         public function estimateRowCount( $table, $var = '*', $conds = '',
 557                 $fname = __METHOD__, $options = [], $join_conds = []
 558         ) {
 559                 $conds = $this->normalizeConditions( $conds, $fname );
 560                 $column = $this->extractSingleFieldFromList( $var );
 561                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 562                         $conds[] = "$column IS NOT NULL";
 563                 }
 564
 565                 $options['EXPLAIN'] = true;
 566                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 567                 if ( $res === false ) {
 568                         return false;
 569                 }
 570                 if ( !$this->numRows( $res ) ) {
 571                         return 0;
 572                 }
 573
 574                 $rows = 1;
 575                 foreach ( $res as $plan ) {
 576                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 577                 }
 578
 579                 return (int)$rows;
 580         }
 581
 582         public function tableExists( $table, $fname = __METHOD__ ) {
 583                 // Split database and table into proper variables as Database::tableName() returns
 584                 // shared tables prefixed with their database, which do not work in SHOW TABLES statements
 585                 list( $database, , $prefix, $table ) = $this->qualifiedTableComponents( $table );
 586                 $tableName = "{$prefix}{$table}";
 587
 588                 if ( isset( $this->sessionTempTables[$tableName] ) ) {
 589                         return true; // already known to exist and won't show in SHOW TABLES anyway
 590                 }
 591
 592                 // We can't use buildLike() here, because it specifies an escape character
 593                 // other than the backslash, which is the only one supported by SHOW TABLES
 594                 $encLike = $this->escapeLikeInternal( $tableName, '\\' );
 595
 596                 // If the database has been specified (such as for shared tables), use "FROM"
 597                 if ( $database !== '' ) {
 598                         $encDatabase = $this->addIdentifierQuotes( $database );
 599                         $query = "SHOW TABLES FROM $encDatabase LIKE '$encLike'";
 600                 } else {
 601                         $query = "SHOW TABLES LIKE '$encLike'";
 602                 }
 603
 604                 return $this->query( $query, $fname )->numRows() > 0;
 605         }
 606
 607         /**
 608          * @param string $table
 609          * @param string $field
 610          * @return bool|MySQLField
 611          */
 612         public function fieldInfo( $table, $field ) {
 613                 $table = $this->tableName( $table );
 614                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, true );
 615                 if ( !$res ) {
 616                         return false;
 617                 }
 618                 $n = $this->mysqlNumFields( $res->result );
 619                 for ( $i = 0; $i < $n; $i++ ) {
 620                         $meta = $this->mysqlFetchField( $res->result, $i );
 621                         if ( $field == $meta->name ) {
 622                                 return new MySQLField( $meta );
 623                         }
 624                 }
 625
 626                 return false;
 627         }
 628
 629         /**
 630          * Get column information from a result
 631          *
 632          * @param resource $res Raw result
 633          * @param int $n
 634          * @return stdClass
 635          */
 636         abstract protected function mysqlFetchField( $res, $n );
 637
 638         /**
 639          * Get information about an index into an object
 640          * Returns false if the index does not exist
 641          *
 642          * @param string $table
 643          * @param string $index
 644          * @param string $fname
 645          * @return bool|array|null False or null on failure
 646          */
 647         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 648                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 649                 # SHOW INDEX should work for 3.x and up:
 650                 # https://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 651                 $table = $this->tableName( $table );
 652                 $index = $this->indexName( $index );
 653
 654                 $sql = 'SHOW INDEX FROM ' . $table;
 655                 $res = $this->query( $sql, $fname );
 656
 657                 if ( !$res ) {
 658                         return null;
 659                 }
 660
 661                 $result = [];
 662
 663                 foreach ( $res as $row ) {
 664                         if ( $row->Key_name == $index ) {
 665                                 $result[] = $row;
 666                         }
 667                 }
 668
 669                 return $result ?: false;
 670         }
 671
 672         /**
 673          * @param string $s
 674          * @return string
 675          */
 676         public function strencode( $s ) {
 677                 return $this->mysqlRealEscapeString( $s );
 678         }
 679
 680         /**
 681          * @param string $s
 682          * @return mixed
 683          */
 684         abstract protected function mysqlRealEscapeString( $s );
 685
 686         public function addQuotes( $s ) {
 687                 if ( is_bool( $s ) ) {
 688                         // Parent would transform to int, which does not play nice with MySQL type juggling.
 689                         // When searching for an int in a string column, the strings are cast to int, which
 690                         // means false would match any string not starting with a number.
 691                         $s = (string)(int)$s;
 692                 }
 693                 return parent::addQuotes( $s );
 694         }
 695
 696         /**
 697          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 698          *
 699          * @param string $s
 700          * @return string
 701          */
 702         public function addIdentifierQuotes( $s ) {
 703                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 704                 // Remove NUL bytes and escape backticks by doubling
 705                 return '`' . str_replace( [ "\0", '`' ], [ '', '``' ], $s ) . '`';
 706         }
 707
 708         /**
 709          * @param string $name
 710          * @return bool
 711          */
 712         public function isQuotedIdentifier( $name ) {
 713                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 714         }
 715
 716         public function getLag() {
 717                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 718                         return $this->getLagFromPtHeartbeat();
 719                 } else {
 720                         return $this->getLagFromSlaveStatus();
 721                 }
 722         }
 723
 724         /**
 725          * @return string
 726          */
 727         protected function getLagDetectionMethod() {
 728                 return $this->lagDetectionMethod;
 729         }
 730
 731         /**
 732          * @return bool|int
 733          */
 734         protected function getLagFromSlaveStatus() {
 735                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__ );
 736                 $row = $res ? $res->fetchObject() : false;
 737                 // If the server is not replicating, there will be no row
 738                 if ( $row && strval( $row->Seconds_Behind_Master ) !== '' ) {
 739                         return intval( $row->Seconds_Behind_Master );
 740                 }
 741
 742                 return false;
 743         }
 744
 745         /**
 746          * @return bool|float
 747          */
 748         protected function getLagFromPtHeartbeat() {
 749                 $options = $this->lagDetectionOptions;
 750
 751                 $currentTrxInfo = $this->getRecordedTransactionLagStatus();
 752                 if ( $currentTrxInfo ) {
 753                         // There is an active transaction and the initial lag was already queried
 754                         $staleness = microtime( true ) - $currentTrxInfo['since'];
 755                         if ( $staleness > self::LAG_STALE_WARN_THRESHOLD ) {
 756                                 // Avoid returning higher and higher lag value due to snapshot age
 757                                 // given that the isolation level will typically be REPEATABLE-READ
 758                                 $this->queryLogger->warning(
 759                                         "Using cached lag value for {db_server} due to active transaction",
 760                                         $this->getLogContext( [ 'method' => __METHOD__, 'age' => $staleness ] )
 761                                 );
 762                         }
 763
 764                         return $currentTrxInfo['lag'];
 765                 }
 766
 767                 if ( isset( $options['conds'] ) ) {
 768                         // Best method for multi-DC setups: use logical channel names
 769                         $data = $this->getHeartbeatData( $options['conds'] );
 770                 } else {
 771                         // Standard method: use master server ID (works with stock pt-heartbeat)
 772                         $masterInfo = $this->getMasterServerInfo();
 773                         if ( !$masterInfo ) {
 774                                 $this->queryLogger->error(
 775                                         "Unable to query master of {db_server} for server ID",
 776                                         $this->getLogContext( [
 777                                                 'method' => __METHOD__
 778                                         ] )
 779                                 );
 780
 781                                 return false; // could not get master server ID
 782                         }
 783
 784                         $conds = [ 'server_id' => intval( $masterInfo['serverId'] ) ];
 785                         $data = $this->getHeartbeatData( $conds );
 786                 }
 787
 788                 list( $time, $nowUnix ) = $data;
 789                 if ( $time !== null ) {
 790                         // @time is in ISO format like "2015-09-25T16:48:10.000510"
 791                         $dateTime = new DateTime( $time, new DateTimeZone( 'UTC' ) );
 792                         $timeUnix = (int)$dateTime->format( 'U' ) + $dateTime->format( 'u' ) / 1e6;
 793
 794                         return max( $nowUnix - $timeUnix, 0.0 );
 795                 }
 796
 797                 $this->queryLogger->error(
 798                         "Unable to find pt-heartbeat row for {db_server}",
 799                         $this->getLogContext( [
 800                                 'method' => __METHOD__
 801                         ] )
 802                 );
 803
 804                 return false;
 805         }
 806
 807         protected function getMasterServerInfo() {
 808                 $cache = $this->srvCache;
 809                 $key = $cache->makeGlobalKey(
 810                         'mysql',
 811                         'master-info',
 812                         // Using one key for all cluster replica DBs is preferable
 813                         $this->getLBInfo( 'clusterMasterHost' ) ?: $this->getServer()
 814                 );
 815                 $fname = __METHOD__;
 816
 817                 return $cache->getWithSetCallback(
 818                         $key,
 819                         $cache::TTL_INDEFINITE,
 820                         function () use ( $cache, $key, $fname ) {
 821                                 // Get and leave a lock key in place for a short period
 822                                 if ( !$cache->lock( $key, 0, 10 ) ) {
 823                                         return false; // avoid master connection spike slams
 824                                 }
 825
 826                                 $conn = $this->getLazyMasterHandle();
 827                                 if ( !$conn ) {
 828                                         return false; // something is misconfigured
 829                                 }
 830
 831                                 // Connect to and query the master; catch errors to avoid outages
 832                                 try {
 833                                         $res = $conn->query( 'SELECT @@server_id AS id', $fname );
 834                                         $row = $res ? $res->fetchObject() : false;
 835                                         $id = $row ? (int)$row->id : 0;
 836                                 } catch ( DBError $e ) {
 837                                         $id = 0;
 838                                 }
 839
 840                                 // Cache the ID if it was retrieved
 841                                 return $id ? [ 'serverId' => $id, 'asOf' => time() ] : false;
 842                         }
 843                 );
 844         }
 845
 846         /**
 847          * @param array $conds WHERE clause conditions to find a row
 848          * @return array (heartbeat `ts` column value or null, UNIX timestamp) for the newest beat
 849          * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html
 850          */
 851         protected function getHeartbeatData( array $conds ) {
 852                 // Query time and trip time are not counted
 853                 $nowUnix = microtime( true );
 854                 // Do not bother starting implicit transactions here
 855                 $this->clearFlag( self::DBO_TRX, self::REMEMBER_PRIOR );
 856                 try {
 857                         $whereSQL = $this->makeList( $conds, self::LIST_AND );
 858                         // Use ORDER BY for channel based queries since that field might not be UNIQUE.
 859                         // Note: this would use "TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6))" but the
 860                         // percision field is not supported in MySQL <= 5.5.
 861                         $res = $this->query(
 862                                 "SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1",
 863                                 __METHOD__
 864                         );
 865                         $row = $res ? $res->fetchObject() : false;
 866                 } finally {
 867                         $this->restoreFlags();
 868                 }
 869
 870                 return [ $row ? $row->ts : null, $nowUnix ];
 871         }
 872
 873         protected function getApproximateLagStatus() {
 874                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 875                         // Disable caching since this is fast enough and we don't wan't
 876                         // to be *too* pessimistic by having both the cache TTL and the
 877                         // pt-heartbeat interval count as lag in getSessionLagStatus()
 878                         return parent::getApproximateLagStatus();
 879                 }
 880
 881                 $key = $this->srvCache->makeGlobalKey( 'mysql-lag', $this->getServer() );
 882                 $approxLag = $this->srvCache->get( $key );
 883                 if ( !$approxLag ) {
 884                         $approxLag = parent::getApproximateLagStatus();
 885                         $this->srvCache->set( $key, $approxLag, 1 );
 886                 }
 887
 888                 return $approxLag;
 889         }
 890
 891         public function masterPosWait( DBMasterPos $pos, $timeout ) {
 892                 if ( !( $pos instanceof MySQLMasterPos ) ) {
 893                         throw new InvalidArgumentException( "Position not an instance of MySQLMasterPos" );
 894                 }
 895
 896                 if ( $this->getLBInfo( 'is static' ) === true ) {
 897                         return 0; // this is a copy of a read-only dataset with no master DB
 898                 } elseif ( $this->lastKnownReplicaPos && $this->lastKnownReplicaPos->hasReached( $pos ) ) {
 899                         return 0; // already reached this point for sure
 900                 }
 901
 902                 // Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 903                 if ( $pos->getGTIDs() ) {
 904                         // Ignore GTIDs from domains exclusive to the master DB (presumably inactive)
 905                         $rpos = $this->getReplicaPos();
 906                         $gtidsWait = $rpos ? MySQLMasterPos::getCommonDomainGTIDs( $pos, $rpos ) : [];
 907                         if ( !$gtidsWait ) {
 908                                 $this->queryLogger->error(
 909                                         "No GTIDs with the same domain between master ($pos) and replica ($rpos)",
 910                                         $this->getLogContext( [
 911                                                 'method' => __METHOD__,
 912                                         ] )
 913                                 );
 914
 915                                 return -1; // $pos is from the wrong cluster?
 916                         }
 917                         // Wait on the GTID set (MariaDB only)
 918                         $gtidArg = $this->addQuotes( implode( ',', $gtidsWait ) );
 919                         if ( strpos( $gtidArg, ':' ) !== false ) {
 920                                 // MySQL GTIDs, e.g "source_id:transaction_id"
 921                                 $res = $this->doQuery( "SELECT WAIT_FOR_EXECUTED_GTID_SET($gtidArg, $timeout)" );
 922                         } else {
 923                                 // MariaDB GTIDs, e.g."domain:server:sequence"
 924                                 $res = $this->doQuery( "SELECT MASTER_GTID_WAIT($gtidArg, $timeout)" );
 925                         }
 926                 } else {
 927                         // Wait on the binlog coordinates
 928                         $encFile = $this->addQuotes( $pos->getLogFile() );
 929                         $encPos = intval( $pos->getLogPosition()[$pos::CORD_EVENT] );
 930                         $res = $this->doQuery( "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)" );
 931                 }
 932
 933                 $row = $res ? $this->fetchRow( $res ) : false;
 934                 if ( !$row ) {
 935                         throw new DBExpectedError( $this, "Replication wait failed: {$this->lastError()}" );
 936                 }
 937
 938                 // Result can be NULL (error), -1 (timeout), or 0+ per the MySQL manual
 939                 $status = ( $row[0] !== null ) ? intval( $row[0] ) : null;
 940                 if ( $status === null ) {
 941                         if ( !$pos->getGTIDs() ) {
 942                                 // T126436: jobs programmed to wait on master positions might be referencing
 943                                 // binlogs with an old master hostname; this makes MASTER_POS_WAIT() return null.
 944                                 // Try to detect this case and treat the replica DB as having reached the given
 945                                 // position (any master switchover already requires that the new master be caught
 946                                 // up before the switch).
 947                                 $replicationPos = $this->getReplicaPos();
 948                                 if ( $replicationPos && !$replicationPos->channelsMatch( $pos ) ) {
 949                                         $this->lastKnownReplicaPos = $replicationPos;
 950                                         $status = 0;
 951                                 }
 952                         }
 953                 } elseif ( $status >= 0 ) {
 954                         // Remember that this position was reached to save queries next time
 955                         $this->lastKnownReplicaPos = $pos;
 956                 }
 957
 958                 return $status;
 959         }
 960
 961         /**
 962          * Get the position of the master from SHOW SLAVE STATUS
 963          *
 964          * @return MySQLMasterPos|bool
 965          */
 966         public function getReplicaPos() {
 967                 $now = microtime( true ); // as-of-time *before* fetching GTID variables
 968
 969                 if ( $this->useGTIDs() ) {
 970                         // Try to use GTIDs, fallbacking to binlog positions if not possible
 971                         $data = $this->getServerGTIDs( __METHOD__ );
 972                         // Use gtid_slave_pos for MariaDB and gtid_executed for MySQL
 973                         foreach ( [ 'gtid_slave_pos', 'gtid_executed' ] as $name ) {
 974                                 if ( isset( $data[$name] ) && strlen( $data[$name] ) ) {
 975                                         return new MySQLMasterPos( $data[$name], $now );
 976                                 }
 977                         }
 978                 }
 979
 980                 $data = $this->getServerRoleStatus( 'SLAVE', __METHOD__ );
 981                 if ( $data && strlen( $data['Relay_Master_Log_File'] ) ) {
 982                         return new MySQLMasterPos(
 983                                 "{$data['Relay_Master_Log_File']}/{$data['Exec_Master_Log_Pos']}",
 984                                 $now
 985                         );
 986                 }
 987
 988                 return false;
 989         }
 990
 991         /**
 992          * Get the position of the master from SHOW MASTER STATUS
 993          *
 994          * @return MySQLMasterPos|bool
 995          */
 996         public function getMasterPos() {
 997                 $now = microtime( true ); // as-of-time *before* fetching GTID variables
 998
 999                 $pos = false;
1000                 if ( $this->useGTIDs() ) {
1001                         // Try to use GTIDs, fallbacking to binlog positions if not possible
1002                         $data = $this->getServerGTIDs( __METHOD__ );
1003                         // Use gtid_binlog_pos for MariaDB and gtid_executed for MySQL
1004                         foreach ( [ 'gtid_binlog_pos', 'gtid_executed' ] as $name ) {
1005                                 if ( isset( $data[$name] ) && strlen( $data[$name] ) ) {
1006                                         $pos = new MySQLMasterPos( $data[$name], $now );
1007                                         break;
1008                                 }
1009                         }
1010                         // Filter domains that are inactive or not relevant to the session
1011                         if ( $pos ) {
1012                                 $pos->setActiveOriginServerId( $this->getServerId() );
1013                                 $pos->setActiveOriginServerUUID( $this->getServerUUID() );
1014                                 if ( isset( $data['gtid_domain_id'] ) ) {
1015                                         $pos->setActiveDomain( $data['gtid_domain_id'] );
1016                                 }
1017                         }
1018                 }
1019
1020                 if ( !$pos ) {
1021                         $data = $this->getServerRoleStatus( 'MASTER', __METHOD__ );
1022                         if ( $data && strlen( $data['File'] ) ) {
1023                                 $pos = new MySQLMasterPos( "{$data['File']}/{$data['Position']}", $now );
1024                         }
1025                 }
1026
1027                 return $pos;
1028         }
1029
1030         /**
1031          * @return int
1032          * @throws DBQueryError If the variable doesn't exist for some reason
1033          */
1034         protected function getServerId() {
1035                 $fname = __METHOD__;
1036                 return $this->srvCache->getWithSetCallback(
1037                         $this->srvCache->makeGlobalKey( 'mysql-server-id', $this->getServer() ),
1038                         self::SERVER_ID_CACHE_TTL,
1039                         function () use ( $fname ) {
1040                                 $res = $this->query( "SELECT @@server_id AS id", $fname );
1041                                 return intval( $this->fetchObject( $res )->id );
1042                         }
1043                 );
1044         }
1045
1046         /**
1047          * @return string|null
1048          */
1049         protected function getServerUUID() {
1050                 return $this->srvCache->getWithSetCallback(
1051                         $this->srvCache->makeGlobalKey( 'mysql-server-uuid', $this->getServer() ),
1052                         self::SERVER_ID_CACHE_TTL,
1053                         function () {
1054                                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'server_uuid'" );
1055                                 $row = $this->fetchObject( $res );
1056
1057                                 return $row ? $row->Value : null;
1058                         }
1059                 );
1060         }
1061
1062         /**
1063          * @param string $fname
1064          * @return string[]
1065          */
1066         protected function getServerGTIDs( $fname = __METHOD__ ) {
1067                 $map = [];
1068                 // Get global-only variables like gtid_executed
1069                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'gtid_%'", $fname );
1070                 foreach ( $res as $row ) {
1071                         $map[$row->Variable_name] = $row->Value;
1072                 }
1073                 // Get session-specific (e.g. gtid_domain_id since that is were writes will log)
1074                 $res = $this->query( "SHOW SESSION VARIABLES LIKE 'gtid_%'", $fname );
1075                 foreach ( $res as $row ) {
1076                         $map[$row->Variable_name] = $row->Value;
1077                 }
1078
1079                 return $map;
1080         }
1081
1082         /**
1083          * @param string $role One of "MASTER"/"SLAVE"
1084          * @param string $fname
1085          * @return string[] Latest available server status row
1086          */
1087         protected function getServerRoleStatus( $role, $fname = __METHOD__ ) {
1088                 return $this->query( "SHOW $role STATUS", $fname )->fetchRow() ?: [];
1089         }
1090
1091         public function serverIsReadOnly() {
1092                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'read_only'", __METHOD__ );
1093                 $row = $this->fetchObject( $res );
1094
1095                 return $row ? ( strtolower( $row->Value ) === 'on' ) : false;
1096         }
1097
1098         /**
1099          * @param string $index
1100          * @return string
1101          */
1102         function useIndexClause( $index ) {
1103                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
1104         }
1105
1106         /**
1107          * @param string $index
1108          * @return string
1109          */
1110         function ignoreIndexClause( $index ) {
1111                 return "IGNORE INDEX (" . $this->indexName( $index ) . ")";
1112         }
1113
1114         /**
1115          * @return string
1116          */
1117         function lowPriorityOption() {
1118                 return 'LOW_PRIORITY';
1119         }
1120
1121         /**
1122          * @return string
1123          */
1124         public function getSoftwareLink() {
1125                 // MariaDB includes its name in its version string; this is how MariaDB's version of
1126                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
1127                 // in libmysql/libmysql.c).
1128                 $version = $this->getServerVersion();
1129                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
1130                         return '[{{int:version-db-mariadb-url}} MariaDB]';
1131                 }
1132
1133                 // Percona Server's version suffix is not very distinctive, and @@version_comment
1134                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
1135                 // (Even Percona's version of mysql doesn't try to make the distinction.)
1136                 return '[{{int:version-db-mysql-url}} MySQL]';
1137         }
1138
1139         /**
1140          * @return string
1141          */
1142         public function getServerVersion() {
1143                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
1144                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
1145                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
1146                 if ( $this->serverVersion === null ) {
1147                         $this->serverVersion = $this->selectField( '', 'VERSION()', '', __METHOD__ );
1148                 }
1149                 return $this->serverVersion;
1150         }
1151
1152         /**
1153          * @param array $options
1154          */
1155         public function setSessionOptions( array $options ) {
1156                 if ( isset( $options['connTimeout'] ) ) {
1157                         $timeout = (int)$options['connTimeout'];
1158                         $this->query( "SET net_read_timeout=$timeout" );
1159                         $this->query( "SET net_write_timeout=$timeout" );
1160                 }
1161         }
1162
1163         /**
1164          * @param string &$sql
1165          * @param string &$newLine
1166          * @return bool
1167          */
1168         public function streamStatementEnd( &$sql, &$newLine ) {
1169                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
1170                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
1171                         $this->delimiter = $m[1];
1172                         $newLine = '';
1173                 }
1174
1175                 return parent::streamStatementEnd( $sql, $newLine );
1176         }
1177
1178         /**
1179          * Check to see if a named lock is available. This is non-blocking.
1180          *
1181          * @param string $lockName Name of lock to poll
1182          * @param string $method Name of method calling us
1183          * @return bool
1184          * @since 1.20
1185          */
1186         public function lockIsFree( $lockName, $method ) {
1187                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1188                         return false; // already held
1189                 }
1190
1191                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1192                 $result = $this->query( "SELECT IS_FREE_LOCK($encName) AS lockstatus", $method );
1193                 $row = $this->fetchObject( $result );
1194
1195                 return ( $row->lockstatus == 1 );
1196         }
1197
1198         /**
1199          * @param string $lockName
1200          * @param string $method
1201          * @param int $timeout
1202          * @return bool
1203          */
1204         public function lock( $lockName, $method, $timeout = 5 ) {
1205                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1206                 $result = $this->query( "SELECT GET_LOCK($encName, $timeout) AS lockstatus", $method );
1207                 $row = $this->fetchObject( $result );
1208
1209                 if ( $row->lockstatus == 1 ) {
1210                         parent::lock( $lockName, $method, $timeout ); // record
1211                         return true;
1212                 }
1213
1214                 $this->queryLogger->info( __METHOD__ . " failed to acquire lock '{lockname}'",
1215                         [ 'lockname' => $lockName ] );
1216
1217                 return false;
1218         }
1219
1220         /**
1221          * FROM MYSQL DOCS:
1222          * https://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
1223          * @param string $lockName
1224          * @param string $method
1225          * @return bool
1226          */
1227         public function unlock( $lockName, $method ) {
1228                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1229                 $result = $this->query( "SELECT RELEASE_LOCK($encName) as lockstatus", $method );
1230                 $row = $this->fetchObject( $result );
1231
1232                 if ( $row->lockstatus == 1 ) {
1233                         parent::unlock( $lockName, $method ); // record
1234                         return true;
1235                 }
1236
1237                 $this->queryLogger->warning( __METHOD__ . " failed to release lock '$lockName'\n" );
1238
1239                 return false;
1240         }
1241
1242         private function makeLockName( $lockName ) {
1243                 // https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
1244                 // Newer version enforce a 64 char length limit.
1245                 return ( strlen( $lockName ) > 64 ) ? sha1( $lockName ) : $lockName;
1246         }
1247
1248         public function namedLocksEnqueue() {
1249                 return true;
1250         }
1251
1252         public function tableLocksHaveTransactionScope() {
1253                 return false; // tied to TCP connection
1254         }
1255
1256         protected function doLockTables( array $read, array $write, $method ) {
1257                 $items = [];
1258                 foreach ( $write as $table ) {
1259                         $items[] = $this->tableName( $table ) . ' WRITE';
1260                 }
1261                 foreach ( $read as $table ) {
1262                         $items[] = $this->tableName( $table ) . ' READ';
1263                 }
1264
1265                 $sql = "LOCK TABLES " . implode( ',', $items );
1266                 $this->query( $sql, $method );
1267
1268                 return true;
1269         }
1270
1271         protected function doUnlockTables( $method ) {
1272                 $this->query( "UNLOCK TABLES", $method );
1273
1274                 return true;
1275         }
1276
1277         /**
1278          * @param bool $value
1279          */
1280         public function setBigSelects( $value = true ) {
1281                 if ( $value === 'default' ) {
1282                         if ( $this->defaultBigSelects === null ) {
1283                                 # Function hasn't been called before so it must already be set to the default
1284                                 return;
1285                         } else {
1286                                 $value = $this->defaultBigSelects;
1287                         }
1288                 } elseif ( $this->defaultBigSelects === null ) {
1289                         $this->defaultBigSelects =
1290                                 (bool)$this->selectField( false, '@@sql_big_selects', '', __METHOD__ );
1291                 }
1292                 $encValue = $value ? '1' : '0';
1293                 $this->query( "SET sql_big_selects=$encValue", __METHOD__ );
1294         }
1295
1296         /**
1297          * DELETE where the condition is a join. MySql uses multi-table deletes.
1298          * @param string $delTable
1299          * @param string $joinTable
1300          * @param string $delVar
1301          * @param string $joinVar
1302          * @param array|string $conds
1303          * @param bool|string $fname
1304          * @throws DBUnexpectedError
1305          */
1306         public function deleteJoin(
1307                 $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__
1308         ) {
1309                 if ( !$conds ) {
1310                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with empty $conds' );
1311                 }
1312
1313                 $delTable = $this->tableName( $delTable );
1314                 $joinTable = $this->tableName( $joinTable );
1315                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1316
1317                 if ( $conds != '*' ) {
1318                         $sql .= ' AND ' . $this->makeList( $conds, self::LIST_AND );
1319                 }
1320
1321                 $this->query( $sql, $fname );
1322         }
1323
1324         /**
1325          * @param string $table
1326          * @param array $rows
1327          * @param array $uniqueIndexes
1328          * @param array $set
1329          * @param string $fname
1330          * @return bool
1331          */
1332         public function upsert( $table, array $rows, array $uniqueIndexes,
1333                 array $set, $fname = __METHOD__
1334         ) {
1335                 if ( !count( $rows ) ) {
1336                         return true; // nothing to do
1337                 }
1338
1339                 if ( !is_array( reset( $rows ) ) ) {
1340                         $rows = [ $rows ];
1341                 }
1342
1343                 $table = $this->tableName( $table );
1344                 $columns = array_keys( $rows[0] );
1345
1346                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
1347                 $rowTuples = [];
1348                 foreach ( $rows as $row ) {
1349                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
1350                 }
1351                 $sql .= implode( ',', $rowTuples );
1352                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, self::LIST_SET );
1353
1354                 $this->query( $sql, $fname );
1355
1356                 return true;
1357         }
1358
1359         /**
1360          * Determines how long the server has been up
1361          *
1362          * @return int
1363          */
1364         public function getServerUptime() {
1365                 $vars = $this->getMysqlStatus( 'Uptime' );
1366
1367                 return (int)$vars['Uptime'];
1368         }
1369
1370         /**
1371          * Determines if the last failure was due to a deadlock
1372          *
1373          * @return bool
1374          */
1375         public function wasDeadlock() {
1376                 return $this->lastErrno() == 1213;
1377         }
1378
1379         /**
1380          * Determines if the last failure was due to a lock timeout
1381          *
1382          * @return bool
1383          */
1384         public function wasLockTimeout() {
1385                 return $this->lastErrno() == 1205;
1386         }
1387
1388         /**
1389          * Determines if the last failure was due to the database being read-only.
1390          *
1391          * @return bool
1392          */
1393         public function wasReadOnlyError() {
1394                 return $this->lastErrno() == 1223 ||
1395                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1396         }
1397
1398         public function wasConnectionError( $errno ) {
1399                 return $errno == 2013 || $errno == 2006;
1400         }
1401
1402         protected function wasKnownStatementRollbackError() {
1403                 $errno = $this->lastErrno();
1404
1405                 if ( $errno === 1205 ) { // lock wait timeout
1406                         // Note that this is uncached to avoid stale values of SET is used
1407                         $row = $this->selectRow(
1408                                 false,
1409                                 [ 'innodb_rollback_on_timeout' => '@@innodb_rollback_on_timeout' ],
1410                                 [],
1411                                 __METHOD__
1412                         );
1413                         // https://dev.mysql.com/doc/refman/5.7/en/innodb-error-handling.html
1414                         // https://dev.mysql.com/doc/refman/5.5/en/innodb-parameters.html
1415                         return $row->innodb_rollback_on_timeout ? false : true;
1416                 }
1417
1418                 // See https://dev.mysql.com/doc/refman/5.5/en/error-messages-server.html
1419                 return in_array( $errno, [ 1022, 1216, 1217, 1137 ], true );
1420         }
1421
1422         /**
1423          * @param string $oldName
1424          * @param string $newName
1425          * @param bool $temporary
1426          * @param string $fname
1427          * @return bool
1428          */
1429         public function duplicateTableStructure(
1430                 $oldName, $newName, $temporary = false, $fname = __METHOD__
1431         ) {
1432                 $tmp = $temporary ? 'TEMPORARY ' : '';
1433                 $newName = $this->addIdentifierQuotes( $newName );
1434                 $oldName = $this->addIdentifierQuotes( $oldName );
1435                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1436
1437                 return $this->query( $query, $fname );
1438         }
1439
1440         /**
1441          * List all tables on the database
1442          *
1443          * @param string|null $prefix Only show tables with this prefix, e.g. mw_
1444          * @param string $fname Calling function name
1445          * @return array
1446          */
1447         public function listTables( $prefix = null, $fname = __METHOD__ ) {
1448                 $result = $this->query( "SHOW TABLES", $fname );
1449
1450                 $endArray = [];
1451
1452                 foreach ( $result as $table ) {
1453                         $vars = get_object_vars( $table );
1454                         $table = array_pop( $vars );
1455
1456                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1457                                 $endArray[] = $table;
1458                         }
1459                 }
1460
1461                 return $endArray;
1462         }
1463
1464         /**
1465          * @param string $tableName
1466          * @param string $fName
1467          * @return bool|ResultWrapper
1468          */
1469         public function dropTable( $tableName, $fName = __METHOD__ ) {
1470                 if ( !$this->tableExists( $tableName, $fName ) ) {
1471                         return false;
1472                 }
1473
1474                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1475         }
1476
1477         /**
1478          * Get status information from SHOW STATUS in an associative array
1479          *
1480          * @param string $which
1481          * @return array
1482          */
1483         private function getMysqlStatus( $which = "%" ) {
1484                 $res = $this->query( "SHOW STATUS LIKE '{$which}'" );
1485                 $status = [];
1486
1487                 foreach ( $res as $row ) {
1488                         $status[$row->Variable_name] = $row->Value;
1489                 }
1490
1491                 return $status;
1492         }
1493
1494         /**
1495          * Lists VIEWs in the database
1496          *
1497          * @param string|null $prefix Only show VIEWs with this prefix, eg.
1498          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1499          * @param string $fname Name of calling function
1500          * @return array
1501          * @since 1.22
1502          */
1503         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1504                 // The name of the column containing the name of the VIEW
1505                 $propertyName = 'Tables_in_' . $this->getDBname();
1506
1507                 // Query for the VIEWS
1508                 $res = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1509                 $allViews = [];
1510                 foreach ( $res as $row ) {
1511                         array_push( $allViews, $row->$propertyName );
1512                 }
1513
1514                 if ( is_null( $prefix ) || $prefix === '' ) {
1515                         return $allViews;
1516                 }
1517
1518                 $filteredViews = [];
1519                 foreach ( $allViews as $viewName ) {
1520                         // Does the name of this VIEW start with the table-prefix?
1521                         if ( strpos( $viewName, $prefix ) === 0 ) {
1522                                 array_push( $filteredViews, $viewName );
1523                         }
1524                 }
1525
1526                 return $filteredViews;
1527         }
1528
1529         /**
1530          * Differentiates between a TABLE and a VIEW.
1531          *
1532          * @param string $name Name of the TABLE/VIEW to test
1533          * @param string|null $prefix
1534          * @return bool
1535          * @since 1.22
1536          */
1537         public function isView( $name, $prefix = null ) {
1538                 return in_array( $name, $this->listViews( $prefix ) );
1539         }
1540
1541         protected function isTransactableQuery( $sql ) {
1542                 return parent::isTransactableQuery( $sql ) &&
1543                         !preg_match( '/^SELECT\s+(GET|RELEASE|IS_FREE)_LOCK\(/', $sql );
1544         }
1545
1546         /**
1547          * @param string $field Field or column to cast
1548          * @return string
1549          */
1550         public function buildIntegerCast( $field ) {
1551                 return 'CAST( ' . $field . ' AS SIGNED )';
1552         }
1553
1554         /*
1555          * @return bool Whether GTID support is used (mockable for testing)
1556          */
1557         protected function useGTIDs() {
1558                 return $this->useGTIDs;
1559         }
1560 }
1561
1562 /**
1563  * @deprecated since 1.29
1564  */
1565 class_alias( DatabaseMysqlBase::class, 'DatabaseMysqlBase' );