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\AtEase\AtEase;
  28 use InvalidArgumentException;
  29 use Exception;
  30 use RuntimeException;
  31 use stdClass;
  32
  33 /**
  34  * Database abstraction object for MySQL.
  35  * Defines methods independent on used MySQL extension.
  36  *
  37  * @ingroup Database
  38  * @since 1.22
  39  * @see Database
  40  */
  41 abstract class DatabaseMysqlBase extends Database {
  42         /** @var MysqlMasterPos */
  43         protected $lastKnownReplicaPos;
  44         /** @var string Method to detect replica DB lag */
  45         protected $lagDetectionMethod;
  46         /** @var array Method to detect replica DB lag */
  47         protected $lagDetectionOptions = [];
  48         /** @var bool bool Whether to use GTID methods */
  49         protected $useGTIDs = false;
  50         /** @var string|null */
  51         protected $sslKeyPath;
  52         /** @var string|null */
  53         protected $sslCertPath;
  54         /** @var string|null */
  55         protected $sslCAFile;
  56         /** @var string|null */
  57         protected $sslCAPath;
  58         /** @var string[]|null */
  59         protected $sslCiphers;
  60         /** @var string sql_mode value to send on connection */
  61         protected $sqlMode;
  62         /** @var bool Use experimental UTF-8 transmission encoding */
  63         protected $utf8Mode;
  64         /** @var bool|null */
  65         protected $defaultBigSelects = null;
  66
  67         /** @var bool|null */
  68         private $insertSelectIsSafe = null;
  69         /** @var stdClass|null */
  70         private $replicationInfoRow = null;
  71
  72         // Cache getServerId() for 24 hours
  73         const SERVER_ID_CACHE_TTL = 86400;
  74
  75         /** @var float Warn if lag estimates are made for transactions older than this many seconds */
  76         const LAG_STALE_WARN_THRESHOLD = 0.100;
  77
  78         /**
  79          * Additional $params include:
  80          *   - lagDetectionMethod : set to one of (Seconds_Behind_Master,pt-heartbeat).
  81          *       pt-heartbeat assumes the table is at heartbeat.heartbeat
  82          *       and uses UTC timestamps in the heartbeat.ts column.
  83          *       (https://www.percona.com/doc/percona-toolkit/2.2/pt-heartbeat.html)
  84          *   - lagDetectionOptions : if using pt-heartbeat, this can be set to an array map to change
  85          *       the default behavior. Normally, the heartbeat row with the server
  86          *       ID of this server's master will be used. Set the "conds" field to
  87          *       override the query conditions, e.g. ['shard' => 's1'].
  88          *   - useGTIDs : use GTID methods like MASTER_GTID_WAIT() when possible.
  89          *   - insertSelectIsSafe : force that native INSERT SELECT is or is not safe [default: null]
  90          *   - sslKeyPath : path to key file [default: null]
  91          *   - sslCertPath : path to certificate file [default: null]
  92          *   - sslCAFile: path to a single certificate authority PEM file [default: null]
  93          *   - sslCAPath : parth to certificate authority PEM directory [default: null]
  94          *   - sslCiphers : array list of allowable ciphers [default: null]
  95          * @param array $params
  96          */
  97         public function __construct( array $params ) {
  98                 $this->lagDetectionMethod = $params['lagDetectionMethod'] ?? 'Seconds_Behind_Master';
  99                 $this->lagDetectionOptions = $params['lagDetectionOptions'] ?? [];
 100                 $this->useGTIDs = !empty( $params['useGTIDs' ] );
 101                 foreach ( [ 'KeyPath', 'CertPath', 'CAFile', 'CAPath', 'Ciphers' ] as $name ) {
 102                         $var = "ssl{$name}";
 103                         if ( isset( $params[$var] ) ) {
 104                                 $this->$var = $params[$var];
 105                         }
 106                 }
 107                 $this->sqlMode = $params['sqlMode'] ?? null;
 108                 $this->utf8Mode = !empty( $params['utf8Mode'] );
 109                 $this->insertSelectIsSafe = isset( $params['insertSelectIsSafe'] )
 110                         ? (bool)$params['insertSelectIsSafe'] : null;
 111
 112                 parent::__construct( $params );
 113         }
 114
 115         /**
 116          * @return string
 117          */
 118         public function getType() {
 119                 return 'mysql';
 120         }
 121
 122         protected function open( $server, $user, $password, $dbName, $schema, $tablePrefix ) {
 123                 $this->close();
 124
 125                 if ( $schema !== null ) {
 126                         throw $this->newExceptionAfterConnectError( "Got schema '$schema'; not supported." );
 127                 }
 128
 129                 $this->server = $server;
 130                 $this->user = $user;
 131                 $this->password = $password;
 132
 133                 $this->installErrorHandler();
 134                 try {
 135                         $this->conn = $this->mysqlConnect( $this->server, $dbName );
 136                 } catch ( Exception $e ) {
 137                         $this->restoreErrorHandler();
 138                         throw $this->newExceptionAfterConnectError( $e->getMessage() );
 139                 }
 140                 $error = $this->restoreErrorHandler();
 141
 142                 if ( !$this->conn ) {
 143                         throw $this->newExceptionAfterConnectError( $error ?: $this->lastError() );
 144                 }
 145
 146                 try {
 147                         $this->currentDomain = new DatabaseDomain(
 148                                 strlen( $dbName ) ? $dbName : null,
 149                                 null,
 150                                 $tablePrefix
 151                         );
 152                         // Abstract over any insane MySQL defaults
 153                         $set = [ 'group_concat_max_len = 262144' ];
 154                         // Set SQL mode, default is turning them all off, can be overridden or skipped with null
 155                         if ( is_string( $this->sqlMode ) ) {
 156                                 $set[] = 'sql_mode = ' . $this->addQuotes( $this->sqlMode );
 157                         }
 158                         // Set any custom settings defined by site config
 159                         // (e.g. https://dev.mysql.com/doc/refman/4.1/en/innodb-parameters.html)
 160                         foreach ( $this->connectionVariables as $var => $val ) {
 161                                 // Escape strings but not numbers to avoid MySQL complaining
 162                                 if ( !is_int( $val ) && !is_float( $val ) ) {
 163                                         $val = $this->addQuotes( $val );
 164                                 }
 165                                 $set[] = $this->addIdentifierQuotes( $var ) . ' = ' . $val;
 166                         }
 167
 168                         if ( $set ) {
 169                                 $this->query(
 170                                         'SET ' . implode( ', ', $set ),
 171                                         __METHOD__,
 172                                         self::QUERY_IGNORE_DBO_TRX | self::QUERY_NO_RETRY
 173                                 );
 174                         }
 175                 } catch ( Exception $e ) {
 176                         throw $this->newExceptionAfterConnectError( $e->getMessage() );
 177                 }
 178         }
 179
 180         protected function doSelectDomain( DatabaseDomain $domain ) {
 181                 if ( $domain->getSchema() !== null ) {
 182                         throw new DBExpectedError(
 183                                 $this,
 184                                 __CLASS__ . ": domain '{$domain->getId()}' has a schema component"
 185                         );
 186                 }
 187
 188                 $database = $domain->getDatabase();
 189                 // A null database means "don't care" so leave it as is and update the table prefix
 190                 if ( $database === null ) {
 191                         $this->currentDomain = new DatabaseDomain(
 192                                 $this->currentDomain->getDatabase(),
 193                                 null,
 194                                 $domain->getTablePrefix()
 195                         );
 196
 197                         return true;
 198                 }
 199
 200                 if ( $database !== $this->getDBname() ) {
 201                         $sql = 'USE ' . $this->addIdentifierQuotes( $database );
 202                         list( $res, $err, $errno ) =
 203                                 $this->executeQuery( $sql, __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 204
 205                         if ( $res === false ) {
 206                                 $this->reportQueryError( $err, $errno, $sql, __METHOD__ );
 207                                 return false; // unreachable
 208                         }
 209                 }
 210
 211                 // Update that domain fields on success (no exception thrown)
 212                 $this->currentDomain = $domain;
 213
 214                 return true;
 215         }
 216
 217         /**
 218          * Open a connection to a MySQL server
 219          *
 220          * @param string $realServer
 221          * @param string|null $dbName
 222          * @return mixed|null Driver connection handle
 223          * @throws DBConnectionError
 224          */
 225         abstract protected function mysqlConnect( $realServer, $dbName );
 226
 227         /**
 228          * @param IResultWrapper|resource $res
 229          * @throws DBUnexpectedError
 230          */
 231         public function freeResult( $res ) {
 232                 AtEase::suppressWarnings();
 233                 $ok = $this->mysqlFreeResult( ResultWrapper::unwrap( $res ) );
 234                 AtEase::restoreWarnings();
 235                 if ( !$ok ) {
 236                         throw new DBUnexpectedError( $this, "Unable to free MySQL result" );
 237                 }
 238         }
 239
 240         /**
 241          * Free result memory
 242          *
 243          * @param resource $res Raw result
 244          * @return bool
 245          */
 246         abstract protected function mysqlFreeResult( $res );
 247
 248         /**
 249          * @param IResultWrapper|resource $res
 250          * @return stdClass|bool
 251          * @throws DBUnexpectedError
 252          */
 253         public function fetchObject( $res ) {
 254                 AtEase::suppressWarnings();
 255                 $row = $this->mysqlFetchObject( ResultWrapper::unwrap( $res ) );
 256                 AtEase::restoreWarnings();
 257
 258                 $errno = $this->lastErrno();
 259                 // Unfortunately, mysql_fetch_object does not reset the last errno.
 260                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 261                 // these are the only errors mysql_fetch_object can cause.
 262                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 263                 if ( $errno == 2000 || $errno == 2013 ) {
 264                         throw new DBUnexpectedError(
 265                                 $this,
 266                                 'Error in fetchObject(): ' . htmlspecialchars( $this->lastError() )
 267                         );
 268                 }
 269
 270                 return $row;
 271         }
 272
 273         /**
 274          * Fetch a result row as an object
 275          *
 276          * @param resource $res Raw result
 277          * @return stdClass
 278          */
 279         abstract protected function mysqlFetchObject( $res );
 280
 281         /**
 282          * @param IResultWrapper|resource $res
 283          * @return array|bool
 284          * @throws DBUnexpectedError
 285          */
 286         public function fetchRow( $res ) {
 287                 AtEase::suppressWarnings();
 288                 $row = $this->mysqlFetchArray( ResultWrapper::unwrap( $res ) );
 289                 AtEase::restoreWarnings();
 290
 291                 $errno = $this->lastErrno();
 292                 // Unfortunately, mysql_fetch_array does not reset the last errno.
 293                 // Only check for CR_SERVER_LOST and CR_UNKNOWN_ERROR, as
 294                 // these are the only errors mysql_fetch_array can cause.
 295                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 296                 if ( $errno == 2000 || $errno == 2013 ) {
 297                         throw new DBUnexpectedError(
 298                                 $this,
 299                                 'Error in fetchRow(): ' . htmlspecialchars( $this->lastError() )
 300                         );
 301                 }
 302
 303                 return $row;
 304         }
 305
 306         /**
 307          * Fetch a result row as an associative and numeric array
 308          *
 309          * @param resource $res Raw result
 310          * @return array|false
 311          */
 312         abstract protected function mysqlFetchArray( $res );
 313
 314         /**
 315          * @throws DBUnexpectedError
 316          * @param IResultWrapper|resource $res
 317          * @return int
 318          */
 319         function numRows( $res ) {
 320                 if ( is_bool( $res ) ) {
 321                         $n = 0;
 322                 } else {
 323                         AtEase::suppressWarnings();
 324                         $n = $this->mysqlNumRows( ResultWrapper::unwrap( $res ) );
 325                         AtEase::restoreWarnings();
 326                 }
 327
 328                 // Unfortunately, mysql_num_rows does not reset the last errno.
 329                 // We are not checking for any errors here, since
 330                 // there are no errors mysql_num_rows can cause.
 331                 // See https://dev.mysql.com/doc/refman/5.0/en/mysql-fetch-row.html.
 332                 // See https://phabricator.wikimedia.org/T44430
 333                 return $n;
 334         }
 335
 336         /**
 337          * Get number of rows in result
 338          *
 339          * @param resource $res Raw result
 340          * @return int
 341          */
 342         abstract protected function mysqlNumRows( $res );
 343
 344         /**
 345          * @param IResultWrapper|resource $res
 346          * @return int
 347          */
 348         public function numFields( $res ) {
 349                 return $this->mysqlNumFields( ResultWrapper::unwrap( $res ) );
 350         }
 351
 352         /**
 353          * Get number of fields in result
 354          *
 355          * @param resource $res Raw result
 356          * @return int
 357          */
 358         abstract protected function mysqlNumFields( $res );
 359
 360         /**
 361          * @param IResultWrapper|resource $res
 362          * @param int $n
 363          * @return string
 364          */
 365         public function fieldName( $res, $n ) {
 366                 return $this->mysqlFieldName( ResultWrapper::unwrap( $res ), $n );
 367         }
 368
 369         /**
 370          * Get the name of the specified field in a result
 371          *
 372          * @param IResultWrapper|resource $res
 373          * @param int $n
 374          * @return string
 375          */
 376         abstract protected function mysqlFieldName( $res, $n );
 377
 378         /**
 379          * mysql_field_type() wrapper
 380          * @param IResultWrapper|resource $res
 381          * @param int $n
 382          * @return string
 383          */
 384         public function fieldType( $res, $n ) {
 385                 return $this->mysqlFieldType( ResultWrapper::unwrap( $res ), $n );
 386         }
 387
 388         /**
 389          * Get the type of the specified field in a result
 390          *
 391          * @param IResultWrapper|resource $res
 392          * @param int $n
 393          * @return string
 394          */
 395         abstract protected function mysqlFieldType( $res, $n );
 396
 397         /**
 398          * @param IResultWrapper|resource $res
 399          * @param int $row
 400          * @return bool
 401          */
 402         public function dataSeek( $res, $row ) {
 403                 return $this->mysqlDataSeek( ResultWrapper::unwrap( $res ), $row );
 404         }
 405
 406         /**
 407          * Move internal result pointer
 408          *
 409          * @param IResultWrapper|resource $res
 410          * @param int $row
 411          * @return bool
 412          */
 413         abstract protected function mysqlDataSeek( $res, $row );
 414
 415         /**
 416          * @return string
 417          */
 418         public function lastError() {
 419                 if ( $this->conn ) {
 420                         # Even if it's non-zero, it can still be invalid
 421                         AtEase::suppressWarnings();
 422                         $error = $this->mysqlError( $this->conn );
 423                         if ( !$error ) {
 424                                 $error = $this->mysqlError();
 425                         }
 426                         AtEase::restoreWarnings();
 427                 } else {
 428                         $error = $this->mysqlError();
 429                 }
 430                 if ( $error ) {
 431                         $error .= ' (' . $this->server . ')';
 432                 }
 433
 434                 return $error;
 435         }
 436
 437         /**
 438          * Returns the text of the error message from previous MySQL operation
 439          *
 440          * @param resource|null $conn Raw connection
 441          * @return string
 442          */
 443         abstract protected function mysqlError( $conn = null );
 444
 445         protected function wasQueryTimeout( $error, $errno ) {
 446                 // https://dev.mysql.com/doc/refman/8.0/en/client-error-reference.html
 447                 // https://phabricator.wikimedia.org/T170638
 448                 return in_array( $errno, [ 2062, 3024 ] );
 449         }
 450
 451         public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 452                 $this->nativeReplace( $table, $rows, $fname );
 453         }
 454
 455         protected function isInsertSelectSafe( array $insertOptions, array $selectOptions ) {
 456                 $row = $this->getReplicationSafetyInfo();
 457                 // For row-based-replication, the resulting changes will be relayed, not the query
 458                 if ( $row->binlog_format === 'ROW' ) {
 459                         return true;
 460                 }
 461                 // LIMIT requires ORDER BY on a unique key or it is non-deterministic
 462                 if ( isset( $selectOptions['LIMIT'] ) ) {
 463                         return false;
 464                 }
 465                 // In MySQL, an INSERT SELECT is only replication safe with row-based
 466                 // replication or if innodb_autoinc_lock_mode is 0. When those
 467                 // conditions aren't met, use non-native mode.
 468                 // While we could try to determine if the insert is safe anyway by
 469                 // checking if the target table has an auto-increment column that
 470                 // isn't set in $varMap, that seems unlikely to be worth the extra
 471                 // complexity.
 472                 return (
 473                         in_array( 'NO_AUTO_COLUMNS', $insertOptions ) ||
 474                         (int)$row->innodb_autoinc_lock_mode === 0
 475                 );
 476         }
 477
 478         /**
 479          * @return stdClass Process cached row
 480          */
 481         protected function getReplicationSafetyInfo() {
 482                 if ( $this->replicationInfoRow === null ) {
 483                         $this->replicationInfoRow = $this->selectRow(
 484                                 false,
 485                                 [
 486                                         'innodb_autoinc_lock_mode' => '@@innodb_autoinc_lock_mode',
 487                                         'binlog_format' => '@@binlog_format',
 488                                 ],
 489                                 [],
 490                                 __METHOD__
 491                         );
 492                 }
 493
 494                 return $this->replicationInfoRow;
 495         }
 496
 497         /**
 498          * Estimate rows in dataset
 499          * Returns estimated count, based on EXPLAIN output
 500          * Takes same arguments as Database::select()
 501          *
 502          * @param string|array $table
 503          * @param string|array $var
 504          * @param string|array $conds
 505          * @param string $fname
 506          * @param string|array $options
 507          * @param array $join_conds
 508          * @return bool|int
 509          */
 510         public function estimateRowCount( $table, $var = '*', $conds = '',
 511                 $fname = __METHOD__, $options = [], $join_conds = []
 512         ) {
 513                 $conds = $this->normalizeConditions( $conds, $fname );
 514                 $column = $this->extractSingleFieldFromList( $var );
 515                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 516                         $conds[] = "$column IS NOT NULL";
 517                 }
 518
 519                 $options['EXPLAIN'] = true;
 520                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 521                 if ( $res === false ) {
 522                         return false;
 523                 }
 524                 if ( !$this->numRows( $res ) ) {
 525                         return 0;
 526                 }
 527
 528                 $rows = 1;
 529                 foreach ( $res as $plan ) {
 530                         $rows *= $plan->rows > 0 ? $plan->rows : 1; // avoid resetting to zero
 531                 }
 532
 533                 return (int)$rows;
 534         }
 535
 536         public function tableExists( $table, $fname = __METHOD__ ) {
 537                 // Split database and table into proper variables as Database::tableName() returns
 538                 // shared tables prefixed with their database, which do not work in SHOW TABLES statements
 539                 list( $database, , $prefix, $table ) = $this->qualifiedTableComponents( $table );
 540                 $tableName = "{$prefix}{$table}";
 541
 542                 if ( isset( $this->sessionTempTables[$tableName] ) ) {
 543                         return true; // already known to exist and won't show in SHOW TABLES anyway
 544                 }
 545
 546                 // We can't use buildLike() here, because it specifies an escape character
 547                 // other than the backslash, which is the only one supported by SHOW TABLES
 548                 $encLike = $this->escapeLikeInternal( $tableName, '\\' );
 549
 550                 // If the database has been specified (such as for shared tables), use "FROM"
 551                 if ( $database !== '' ) {
 552                         $encDatabase = $this->addIdentifierQuotes( $database );
 553                         $query = "SHOW TABLES FROM $encDatabase LIKE '$encLike'";
 554                 } else {
 555                         $query = "SHOW TABLES LIKE '$encLike'";
 556                 }
 557
 558                 return $this->query( $query, $fname )->numRows() > 0;
 559         }
 560
 561         /**
 562          * @param string $table
 563          * @param string $field
 564          * @return bool|MySQLField
 565          */
 566         public function fieldInfo( $table, $field ) {
 567                 $table = $this->tableName( $table );
 568                 $flags = self::QUERY_SILENCE_ERRORS;
 569                 $res = $this->query( "SELECT * FROM $table LIMIT 1", __METHOD__, $flags );
 570                 if ( !$res ) {
 571                         return false;
 572                 }
 573                 $n = $this->mysqlNumFields( ResultWrapper::unwrap( $res ) );
 574                 for ( $i = 0; $i < $n; $i++ ) {
 575                         $meta = $this->mysqlFetchField( ResultWrapper::unwrap( $res ), $i );
 576                         if ( $field == $meta->name ) {
 577                                 return new MySQLField( $meta );
 578                         }
 579                 }
 580
 581                 return false;
 582         }
 583
 584         /**
 585          * Get column information from a result
 586          *
 587          * @param resource $res Raw result
 588          * @param int $n
 589          * @return stdClass
 590          */
 591         abstract protected function mysqlFetchField( $res, $n );
 592
 593         /**
 594          * Get information about an index into an object
 595          * Returns false if the index does not exist
 596          *
 597          * @param string $table
 598          * @param string $index
 599          * @param string $fname
 600          * @return bool|array|null False or null on failure
 601          */
 602         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 603                 # SHOW INDEX works in MySQL 3.23.58, but SHOW INDEXES does not.
 604                 # SHOW INDEX should work for 3.x and up:
 605                 # https://dev.mysql.com/doc/mysql/en/SHOW_INDEX.html
 606                 $table = $this->tableName( $table );
 607                 $index = $this->indexName( $index );
 608
 609                 $sql = 'SHOW INDEX FROM ' . $table;
 610                 $res = $this->query( $sql, $fname );
 611
 612                 if ( !$res ) {
 613                         return null;
 614                 }
 615
 616                 $result = [];
 617
 618                 foreach ( $res as $row ) {
 619                         if ( $row->Key_name == $index ) {
 620                                 $result[] = $row;
 621                         }
 622                 }
 623
 624                 return $result ?: false;
 625         }
 626
 627         /**
 628          * @param string $s
 629          * @return string
 630          */
 631         public function strencode( $s ) {
 632                 return $this->mysqlRealEscapeString( $s );
 633         }
 634
 635         /**
 636          * @param string $s
 637          * @return mixed
 638          */
 639         abstract protected function mysqlRealEscapeString( $s );
 640
 641         public function addQuotes( $s ) {
 642                 if ( is_bool( $s ) ) {
 643                         // Parent would transform to int, which does not play nice with MySQL type juggling.
 644                         // When searching for an int in a string column, the strings are cast to int, which
 645                         // means false would match any string not starting with a number.
 646                         $s = (string)(int)$s;
 647                 }
 648                 return parent::addQuotes( $s );
 649         }
 650
 651         /**
 652          * MySQL uses `backticks` for identifier quoting instead of the sql standard "double quotes".
 653          *
 654          * @param string $s
 655          * @return string
 656          */
 657         public function addIdentifierQuotes( $s ) {
 658                 // Characters in the range \u0001-\uFFFF are valid in a quoted identifier
 659                 // Remove NUL bytes and escape backticks by doubling
 660                 return '`' . str_replace( [ "\0", '`' ], [ '', '``' ], $s ) . '`';
 661         }
 662
 663         /**
 664          * @param string $name
 665          * @return bool
 666          */
 667         public function isQuotedIdentifier( $name ) {
 668                 return strlen( $name ) && $name[0] == '`' && substr( $name, -1, 1 ) == '`';
 669         }
 670
 671         protected function doGetLag() {
 672                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 673                         return $this->getLagFromPtHeartbeat();
 674                 } else {
 675                         return $this->getLagFromSlaveStatus();
 676                 }
 677         }
 678
 679         /**
 680          * @return string
 681          */
 682         protected function getLagDetectionMethod() {
 683                 return $this->lagDetectionMethod;
 684         }
 685
 686         /**
 687          * @return bool|int
 688          */
 689         protected function getLagFromSlaveStatus() {
 690                 $flags = self::QUERY_SILENCE_ERRORS | self::QUERY_IGNORE_DBO_TRX;
 691                 $res = $this->query( 'SHOW SLAVE STATUS', __METHOD__, $flags );
 692                 $row = $res ? $res->fetchObject() : false;
 693                 // If the server is not replicating, there will be no row
 694                 if ( $row && strval( $row->Seconds_Behind_Master ) !== '' ) {
 695                         return intval( $row->Seconds_Behind_Master );
 696                 }
 697
 698                 return false;
 699         }
 700
 701         /**
 702          * @return bool|float
 703          */
 704         protected function getLagFromPtHeartbeat() {
 705                 $options = $this->lagDetectionOptions;
 706
 707                 $currentTrxInfo = $this->getRecordedTransactionLagStatus();
 708                 if ( $currentTrxInfo ) {
 709                         // There is an active transaction and the initial lag was already queried
 710                         $staleness = microtime( true ) - $currentTrxInfo['since'];
 711                         if ( $staleness > self::LAG_STALE_WARN_THRESHOLD ) {
 712                                 // Avoid returning higher and higher lag value due to snapshot age
 713                                 // given that the isolation level will typically be REPEATABLE-READ
 714                                 $this->queryLogger->warning(
 715                                         "Using cached lag value for {db_server} due to active transaction",
 716                                         $this->getLogContext( [
 717                                                 'method' => __METHOD__,
 718                                                 'age' => $staleness,
 719                                                 'trace' => ( new RuntimeException() )->getTraceAsString()
 720                                         ] )
 721                                 );
 722                         }
 723
 724                         return $currentTrxInfo['lag'];
 725                 }
 726
 727                 if ( isset( $options['conds'] ) ) {
 728                         // Best method for multi-DC setups: use logical channel names
 729                         $data = $this->getHeartbeatData( $options['conds'] );
 730                 } else {
 731                         // Standard method: use master server ID (works with stock pt-heartbeat)
 732                         $masterInfo = $this->getMasterServerInfo();
 733                         if ( !$masterInfo ) {
 734                                 $this->queryLogger->error(
 735                                         "Unable to query master of {db_server} for server ID",
 736                                         $this->getLogContext( [
 737                                                 'method' => __METHOD__
 738                                         ] )
 739                                 );
 740
 741                                 return false; // could not get master server ID
 742                         }
 743
 744                         $conds = [ 'server_id' => intval( $masterInfo['serverId'] ) ];
 745                         $data = $this->getHeartbeatData( $conds );
 746                 }
 747
 748                 list( $time, $nowUnix ) = $data;
 749                 if ( $time !== null ) {
 750                         // @time is in ISO format like "2015-09-25T16:48:10.000510"
 751                         $dateTime = new DateTime( $time, new DateTimeZone( 'UTC' ) );
 752                         $timeUnix = (int)$dateTime->format( 'U' ) + $dateTime->format( 'u' ) / 1e6;
 753
 754                         return max( $nowUnix - $timeUnix, 0.0 );
 755                 }
 756
 757                 $this->queryLogger->error(
 758                         "Unable to find pt-heartbeat row for {db_server}",
 759                         $this->getLogContext( [
 760                                 'method' => __METHOD__
 761                         ] )
 762                 );
 763
 764                 return false;
 765         }
 766
 767         protected function getMasterServerInfo() {
 768                 $cache = $this->srvCache;
 769                 $key = $cache->makeGlobalKey(
 770                         'mysql',
 771                         'master-info',
 772                         // Using one key for all cluster replica DBs is preferable
 773                         $this->getLBInfo( 'clusterMasterHost' ) ?: $this->getServer()
 774                 );
 775                 $fname = __METHOD__;
 776
 777                 return $cache->getWithSetCallback(
 778                         $key,
 779                         $cache::TTL_INDEFINITE,
 780                         function () use ( $cache, $key, $fname ) {
 781                                 // Get and leave a lock key in place for a short period
 782                                 if ( !$cache->lock( $key, 0, 10 ) ) {
 783                                         return false; // avoid master connection spike slams
 784                                 }
 785
 786                                 $conn = $this->getLazyMasterHandle();
 787                                 if ( !$conn ) {
 788                                         return false; // something is misconfigured
 789                                 }
 790
 791                                 // Connect to and query the master; catch errors to avoid outages
 792                                 try {
 793                                         $flags = self::QUERY_SILENCE_ERRORS | self::QUERY_IGNORE_DBO_TRX;
 794                                         $res = $conn->query( 'SELECT @@server_id AS id', $fname, $flags );
 795                                         $row = $res ? $res->fetchObject() : false;
 796                                         $id = $row ? (int)$row->id : 0;
 797                                 } catch ( DBError $e ) {
 798                                         $id = 0;
 799                                 }
 800
 801                                 // Cache the ID if it was retrieved
 802                                 return $id ? [ 'serverId' => $id, 'asOf' => time() ] : false;
 803                         }
 804                 );
 805         }
 806
 807         /**
 808          * @param array $conds WHERE clause conditions to find a row
 809          * @return array (heartbeat `ts` column value or null, UNIX timestamp) for the newest beat
 810          * @see https://www.percona.com/doc/percona-toolkit/2.1/pt-heartbeat.html
 811          */
 812         protected function getHeartbeatData( array $conds ) {
 813                 // Query time and trip time are not counted
 814                 $nowUnix = microtime( true );
 815                 $whereSQL = $this->makeList( $conds, self::LIST_AND );
 816                 // Use ORDER BY for channel based queries since that field might not be UNIQUE.
 817                 // Note: this would use "TIMESTAMPDIFF(MICROSECOND,ts,UTC_TIMESTAMP(6))" but the
 818                 // percision field is not supported in MySQL <= 5.5.
 819                 $res = $this->query(
 820                         "SELECT ts FROM heartbeat.heartbeat WHERE $whereSQL ORDER BY ts DESC LIMIT 1",
 821                         __METHOD__,
 822                         self::QUERY_SILENCE_ERRORS | self::QUERY_IGNORE_DBO_TRX
 823                 );
 824                 $row = $res ? $res->fetchObject() : false;
 825
 826                 return [ $row ? $row->ts : null, $nowUnix ];
 827         }
 828
 829         protected function getApproximateLagStatus() {
 830                 if ( $this->getLagDetectionMethod() === 'pt-heartbeat' ) {
 831                         // Disable caching since this is fast enough and we don't wan't
 832                         // to be *too* pessimistic by having both the cache TTL and the
 833                         // pt-heartbeat interval count as lag in getSessionLagStatus()
 834                         return parent::getApproximateLagStatus();
 835                 }
 836
 837                 $key = $this->srvCache->makeGlobalKey( 'mysql-lag', $this->getServer() );
 838                 $approxLag = $this->srvCache->get( $key );
 839                 if ( !$approxLag ) {
 840                         $approxLag = parent::getApproximateLagStatus();
 841                         $this->srvCache->set( $key, $approxLag, 1 );
 842                 }
 843
 844                 return $approxLag;
 845         }
 846
 847         public function masterPosWait( DBMasterPos $pos, $timeout ) {
 848                 if ( !( $pos instanceof MySQLMasterPos ) ) {
 849                         throw new InvalidArgumentException( "Position not an instance of MySQLMasterPos" );
 850                 }
 851
 852                 if ( $this->getLBInfo( 'is static' ) === true ) {
 853                         return 0; // this is a copy of a read-only dataset with no master DB
 854                 } elseif ( $this->lastKnownReplicaPos && $this->lastKnownReplicaPos->hasReached( $pos ) ) {
 855                         return 0; // already reached this point for sure
 856                 }
 857
 858                 // Call doQuery() directly, to avoid opening a transaction if DBO_TRX is set
 859                 if ( $pos->getGTIDs() ) {
 860                         // Ignore GTIDs from domains exclusive to the master DB (presumably inactive)
 861                         $rpos = $this->getReplicaPos();
 862                         $gtidsWait = $rpos ? MySQLMasterPos::getCommonDomainGTIDs( $pos, $rpos ) : [];
 863                         if ( !$gtidsWait ) {
 864                                 $this->queryLogger->error(
 865                                         "No GTIDs with the same domain between master ($pos) and replica ($rpos)",
 866                                         $this->getLogContext( [
 867                                                 'method' => __METHOD__,
 868                                         ] )
 869                                 );
 870
 871                                 return -1; // $pos is from the wrong cluster?
 872                         }
 873                         // Wait on the GTID set (MariaDB only)
 874                         $gtidArg = $this->addQuotes( implode( ',', $gtidsWait ) );
 875                         if ( strpos( $gtidArg, ':' ) !== false ) {
 876                                 // MySQL GTIDs, e.g "source_id:transaction_id"
 877                                 $sql = "SELECT WAIT_FOR_EXECUTED_GTID_SET($gtidArg, $timeout)";
 878                         } else {
 879                                 // MariaDB GTIDs, e.g."domain:server:sequence"
 880                                 $sql = "SELECT MASTER_GTID_WAIT($gtidArg, $timeout)";
 881                         }
 882                 } else {
 883                         // Wait on the binlog coordinates
 884                         $encFile = $this->addQuotes( $pos->getLogFile() );
 885                         $encPos = intval( $pos->getLogPosition()[$pos::CORD_EVENT] );
 886                         $sql = "SELECT MASTER_POS_WAIT($encFile, $encPos, $timeout)";
 887                 }
 888
 889                 list( $res, $err ) = $this->executeQuery( $sql, __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 890                 $row = $res ? $this->fetchRow( $res ) : false;
 891                 if ( !$row ) {
 892                         throw new DBExpectedError( $this, "Replication wait failed: {$err}" );
 893                 }
 894
 895                 // Result can be NULL (error), -1 (timeout), or 0+ per the MySQL manual
 896                 $status = ( $row[0] !== null ) ? intval( $row[0] ) : null;
 897                 if ( $status === null ) {
 898                         if ( !$pos->getGTIDs() ) {
 899                                 // T126436: jobs programmed to wait on master positions might be referencing
 900                                 // binlogs with an old master hostname; this makes MASTER_POS_WAIT() return null.
 901                                 // Try to detect this case and treat the replica DB as having reached the given
 902                                 // position (any master switchover already requires that the new master be caught
 903                                 // up before the switch).
 904                                 $replicationPos = $this->getReplicaPos();
 905                                 if ( $replicationPos && !$replicationPos->channelsMatch( $pos ) ) {
 906                                         $this->lastKnownReplicaPos = $replicationPos;
 907                                         $status = 0;
 908                                 }
 909                         }
 910                 } elseif ( $status >= 0 ) {
 911                         // Remember that this position was reached to save queries next time
 912                         $this->lastKnownReplicaPos = $pos;
 913                 }
 914
 915                 return $status;
 916         }
 917
 918         /**
 919          * Get the position of the master from SHOW SLAVE STATUS
 920          *
 921          * @return MySQLMasterPos|bool
 922          */
 923         public function getReplicaPos() {
 924                 $now = microtime( true ); // as-of-time *before* fetching GTID variables
 925
 926                 if ( $this->useGTIDs() ) {
 927                         // Try to use GTIDs, fallbacking to binlog positions if not possible
 928                         $data = $this->getServerGTIDs( __METHOD__ );
 929                         // Use gtid_slave_pos for MariaDB and gtid_executed for MySQL
 930                         foreach ( [ 'gtid_slave_pos', 'gtid_executed' ] as $name ) {
 931                                 if ( isset( $data[$name] ) && strlen( $data[$name] ) ) {
 932                                         return new MySQLMasterPos( $data[$name], $now );
 933                                 }
 934                         }
 935                 }
 936
 937                 $data = $this->getServerRoleStatus( 'SLAVE', __METHOD__ );
 938                 if ( $data && strlen( $data['Relay_Master_Log_File'] ) ) {
 939                         return new MySQLMasterPos(
 940                                 "{$data['Relay_Master_Log_File']}/{$data['Exec_Master_Log_Pos']}",
 941                                 $now
 942                         );
 943                 }
 944
 945                 return false;
 946         }
 947
 948         /**
 949          * Get the position of the master from SHOW MASTER STATUS
 950          *
 951          * @return MySQLMasterPos|bool
 952          */
 953         public function getMasterPos() {
 954                 $now = microtime( true ); // as-of-time *before* fetching GTID variables
 955
 956                 $pos = false;
 957                 if ( $this->useGTIDs() ) {
 958                         // Try to use GTIDs, fallbacking to binlog positions if not possible
 959                         $data = $this->getServerGTIDs( __METHOD__ );
 960                         // Use gtid_binlog_pos for MariaDB and gtid_executed for MySQL
 961                         foreach ( [ 'gtid_binlog_pos', 'gtid_executed' ] as $name ) {
 962                                 if ( isset( $data[$name] ) && strlen( $data[$name] ) ) {
 963                                         $pos = new MySQLMasterPos( $data[$name], $now );
 964                                         break;
 965                                 }
 966                         }
 967                         // Filter domains that are inactive or not relevant to the session
 968                         if ( $pos ) {
 969                                 $pos->setActiveOriginServerId( $this->getServerId() );
 970                                 $pos->setActiveOriginServerUUID( $this->getServerUUID() );
 971                                 if ( isset( $data['gtid_domain_id'] ) ) {
 972                                         $pos->setActiveDomain( $data['gtid_domain_id'] );
 973                                 }
 974                         }
 975                 }
 976
 977                 if ( !$pos ) {
 978                         $data = $this->getServerRoleStatus( 'MASTER', __METHOD__ );
 979                         if ( $data && strlen( $data['File'] ) ) {
 980                                 $pos = new MySQLMasterPos( "{$data['File']}/{$data['Position']}", $now );
 981                         }
 982                 }
 983
 984                 return $pos;
 985         }
 986
 987         /**
 988          * @return int
 989          * @throws DBQueryError If the variable doesn't exist for some reason
 990          */
 991         protected function getServerId() {
 992                 $fname = __METHOD__;
 993                 return $this->srvCache->getWithSetCallback(
 994                         $this->srvCache->makeGlobalKey( 'mysql-server-id', $this->getServer() ),
 995                         self::SERVER_ID_CACHE_TTL,
 996                         function () use ( $fname ) {
 997                                 $flags = self::QUERY_IGNORE_DBO_TRX;
 998                                 $res = $this->query( "SELECT @@server_id AS id", $fname, $flags );
 999
1000                                 return intval( $this->fetchObject( $res )->id );
1001                         }
1002                 );
1003         }
1004
1005         /**
1006          * @return string|null
1007          */
1008         protected function getServerUUID() {
1009                 $fname = __METHOD__;
1010                 return $this->srvCache->getWithSetCallback(
1011                         $this->srvCache->makeGlobalKey( 'mysql-server-uuid', $this->getServer() ),
1012                         self::SERVER_ID_CACHE_TTL,
1013                         function () use ( $fname ) {
1014                                 $flags = self::QUERY_IGNORE_DBO_TRX;
1015                                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'server_uuid'", $fname, $flags );
1016                                 $row = $this->fetchObject( $res );
1017
1018                                 return $row ? $row->Value : null;
1019                         }
1020                 );
1021         }
1022
1023         /**
1024          * @param string $fname
1025          * @return string[]
1026          */
1027         protected function getServerGTIDs( $fname = __METHOD__ ) {
1028                 $map = [];
1029
1030                 $flags = self::QUERY_IGNORE_DBO_TRX;
1031                 // Get global-only variables like gtid_executed
1032                 $res = $this->query( "SHOW GLOBAL VARIABLES LIKE 'gtid_%'", $fname, $flags );
1033                 foreach ( $res as $row ) {
1034                         $map[$row->Variable_name] = $row->Value;
1035                 }
1036                 // Get session-specific (e.g. gtid_domain_id since that is were writes will log)
1037                 $res = $this->query( "SHOW SESSION VARIABLES LIKE 'gtid_%'", $fname, $flags );
1038                 foreach ( $res as $row ) {
1039                         $map[$row->Variable_name] = $row->Value;
1040                 }
1041
1042                 return $map;
1043         }
1044
1045         /**
1046          * @param string $role One of "MASTER"/"SLAVE"
1047          * @param string $fname
1048          * @return string[] Latest available server status row
1049          */
1050         protected function getServerRoleStatus( $role, $fname = __METHOD__ ) {
1051                 $flags = self::QUERY_IGNORE_DBO_TRX;
1052
1053                 return $this->query( "SHOW $role STATUS", $fname, $flags )->fetchRow() ?: [];
1054         }
1055
1056         public function serverIsReadOnly() {
1057                 // Avoid SHOW to avoid internal temporary tables
1058                 $flags = self::QUERY_IGNORE_DBO_TRX | self::QUERY_SILENCE_ERRORS;
1059                 $res = $this->query( "SELECT @@GLOBAL.read_only AS Value", __METHOD__, $flags );
1060                 $row = $this->fetchObject( $res );
1061
1062                 return $row ? (bool)$row->Value : false;
1063         }
1064
1065         /**
1066          * @param string $index
1067          * @return string
1068          */
1069         function useIndexClause( $index ) {
1070                 return "FORCE INDEX (" . $this->indexName( $index ) . ")";
1071         }
1072
1073         /**
1074          * @param string $index
1075          * @return string
1076          */
1077         function ignoreIndexClause( $index ) {
1078                 return "IGNORE INDEX (" . $this->indexName( $index ) . ")";
1079         }
1080
1081         /**
1082          * @return string
1083          */
1084         public function getSoftwareLink() {
1085                 // MariaDB includes its name in its version string; this is how MariaDB's version of
1086                 // the mysql command-line client identifies MariaDB servers (see mariadb_connection()
1087                 // in libmysql/libmysql.c).
1088                 $version = $this->getServerVersion();
1089                 if ( strpos( $version, 'MariaDB' ) !== false || strpos( $version, '-maria-' ) !== false ) {
1090                         return '[{{int:version-db-mariadb-url}} MariaDB]';
1091                 }
1092
1093                 // Percona Server's version suffix is not very distinctive, and @@version_comment
1094                 // doesn't give the necessary info for source builds, so assume the server is MySQL.
1095                 // (Even Percona's version of mysql doesn't try to make the distinction.)
1096                 return '[{{int:version-db-mysql-url}} MySQL]';
1097         }
1098
1099         /**
1100          * @return string
1101          */
1102         public function getServerVersion() {
1103                 $cache = $this->srvCache;
1104                 $fname = __METHOD__;
1105
1106                 return $cache->getWithSetCallback(
1107                         $cache->makeGlobalKey( 'mysql-server-version', $this->getServer() ),
1108                         $cache::TTL_HOUR,
1109                         function () use ( $fname ) {
1110                                 // Not using mysql_get_server_info() or similar for consistency: in the handshake,
1111                                 // MariaDB 10 adds the prefix "5.5.5-", and only some newer client libraries strip
1112                                 // it off (see RPL_VERSION_HACK in include/mysql_com.h).
1113                                 return $this->selectField( '', 'VERSION()', '', $fname );
1114                         }
1115                 );
1116         }
1117
1118         /**
1119          * @param array $options
1120          */
1121         public function setSessionOptions( array $options ) {
1122                 if ( isset( $options['connTimeout'] ) ) {
1123                         $flags = self::QUERY_IGNORE_DBO_TRX;
1124                         $timeout = (int)$options['connTimeout'];
1125                         $this->query( "SET net_read_timeout=$timeout", __METHOD__, $flags );
1126                         $this->query( "SET net_write_timeout=$timeout", __METHOD__, $flags );
1127                 }
1128         }
1129
1130         /**
1131          * @param string &$sql
1132          * @param string &$newLine
1133          * @return bool
1134          */
1135         public function streamStatementEnd( &$sql, &$newLine ) {
1136                 if ( strtoupper( substr( $newLine, 0, 9 ) ) == 'DELIMITER' ) {
1137                         preg_match( '/^DELIMITER\s+(\S+)/', $newLine, $m );
1138                         $this->delimiter = $m[1];
1139                         $newLine = '';
1140                 }
1141
1142                 return parent::streamStatementEnd( $sql, $newLine );
1143         }
1144
1145         /**
1146          * Check to see if a named lock is available. This is non-blocking.
1147          *
1148          * @param string $lockName Name of lock to poll
1149          * @param string $method Name of method calling us
1150          * @return bool
1151          * @since 1.20
1152          */
1153         public function lockIsFree( $lockName, $method ) {
1154                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1155                         return false; // already held
1156                 }
1157
1158                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1159
1160                 $flags = self::QUERY_IGNORE_DBO_TRX;
1161                 $res = $this->query( "SELECT IS_FREE_LOCK($encName) AS lockstatus", $method, $flags );
1162                 $row = $this->fetchObject( $res );
1163
1164                 return ( $row->lockstatus == 1 );
1165         }
1166
1167         /**
1168          * @param string $lockName
1169          * @param string $method
1170          * @param int $timeout
1171          * @return bool
1172          */
1173         public function lock( $lockName, $method, $timeout = 5 ) {
1174                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1175
1176                 $flags = self::QUERY_IGNORE_DBO_TRX;
1177                 $res = $this->query( "SELECT GET_LOCK($encName, $timeout) AS lockstatus", $method, $flags );
1178                 $row = $this->fetchObject( $res );
1179
1180                 if ( $row->lockstatus == 1 ) {
1181                         parent::lock( $lockName, $method, $timeout ); // record
1182                         return true;
1183                 }
1184
1185                 $this->queryLogger->info( __METHOD__ . " failed to acquire lock '{lockname}'",
1186                         [ 'lockname' => $lockName ] );
1187
1188                 return false;
1189         }
1190
1191         /**
1192          * FROM MYSQL DOCS:
1193          * https://dev.mysql.com/doc/refman/5.0/en/miscellaneous-functions.html#function_release-lock
1194          * @param string $lockName
1195          * @param string $method
1196          * @return bool
1197          */
1198         public function unlock( $lockName, $method ) {
1199                 $encName = $this->addQuotes( $this->makeLockName( $lockName ) );
1200
1201                 $flags = self::QUERY_IGNORE_DBO_TRX;
1202                 $res = $this->query( "SELECT RELEASE_LOCK($encName) as lockstatus", $method, $flags );
1203                 $row = $this->fetchObject( $res );
1204
1205                 if ( $row->lockstatus == 1 ) {
1206                         parent::unlock( $lockName, $method ); // record
1207                         return true;
1208                 }
1209
1210                 $this->queryLogger->warning( __METHOD__ . " failed to release lock '$lockName'\n" );
1211
1212                 return false;
1213         }
1214
1215         private function makeLockName( $lockName ) {
1216                 // https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock
1217                 // Newer version enforce a 64 char length limit.
1218                 return ( strlen( $lockName ) > 64 ) ? sha1( $lockName ) : $lockName;
1219         }
1220
1221         public function namedLocksEnqueue() {
1222                 return true;
1223         }
1224
1225         public function tableLocksHaveTransactionScope() {
1226                 return false; // tied to TCP connection
1227         }
1228
1229         protected function doLockTables( array $read, array $write, $method ) {
1230                 $items = [];
1231                 foreach ( $write as $table ) {
1232                         $items[] = $this->tableName( $table ) . ' WRITE';
1233                 }
1234                 foreach ( $read as $table ) {
1235                         $items[] = $this->tableName( $table ) . ' READ';
1236                 }
1237
1238                 $sql = "LOCK TABLES " . implode( ',', $items );
1239                 $this->query( $sql, $method, self::QUERY_IGNORE_DBO_TRX );
1240
1241                 return true;
1242         }
1243
1244         protected function doUnlockTables( $method ) {
1245                 $this->query( "UNLOCK TABLES", $method, self::QUERY_IGNORE_DBO_TRX );
1246
1247                 return true;
1248         }
1249
1250         /**
1251          * @param bool $value
1252          */
1253         public function setBigSelects( $value = true ) {
1254                 if ( $value === 'default' ) {
1255                         if ( $this->defaultBigSelects === null ) {
1256                                 # Function hasn't been called before so it must already be set to the default
1257                                 return;
1258                         } else {
1259                                 $value = $this->defaultBigSelects;
1260                         }
1261                 } elseif ( $this->defaultBigSelects === null ) {
1262                         $this->defaultBigSelects =
1263                                 (bool)$this->selectField( false, '@@sql_big_selects', '', __METHOD__ );
1264                 }
1265                 $encValue = $value ? '1' : '0';
1266                 $this->query( "SET sql_big_selects=$encValue", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
1267         }
1268
1269         /**
1270          * DELETE where the condition is a join. MySql uses multi-table deletes.
1271          * @param string $delTable
1272          * @param string $joinTable
1273          * @param string $delVar
1274          * @param string $joinVar
1275          * @param array|string $conds
1276          * @param bool|string $fname
1277          * @throws DBUnexpectedError
1278          */
1279         public function deleteJoin(
1280                 $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = __METHOD__
1281         ) {
1282                 if ( !$conds ) {
1283                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with empty $conds' );
1284                 }
1285
1286                 $delTable = $this->tableName( $delTable );
1287                 $joinTable = $this->tableName( $joinTable );
1288                 $sql = "DELETE $delTable FROM $delTable, $joinTable WHERE $delVar=$joinVar ";
1289
1290                 if ( $conds != '*' ) {
1291                         $sql .= ' AND ' . $this->makeList( $conds, self::LIST_AND );
1292                 }
1293
1294                 $this->query( $sql, $fname );
1295         }
1296
1297         public function upsert(
1298                 $table, array $rows, $uniqueIndexes, array $set, $fname = __METHOD__
1299         ) {
1300                 if ( $rows === [] ) {
1301                         return true; // nothing to do
1302                 }
1303
1304                 if ( !is_array( reset( $rows ) ) ) {
1305                         $rows = [ $rows ];
1306                 }
1307
1308                 $table = $this->tableName( $table );
1309                 $columns = array_keys( $rows[0] );
1310
1311                 $sql = "INSERT INTO $table (" . implode( ',', $columns ) . ') VALUES ';
1312                 $rowTuples = [];
1313                 foreach ( $rows as $row ) {
1314                         $rowTuples[] = '(' . $this->makeList( $row ) . ')';
1315                 }
1316                 $sql .= implode( ',', $rowTuples );
1317                 $sql .= " ON DUPLICATE KEY UPDATE " . $this->makeList( $set, self::LIST_SET );
1318
1319                 $this->query( $sql, $fname );
1320
1321                 return true;
1322         }
1323
1324         /**
1325          * Determines how long the server has been up
1326          *
1327          * @return int
1328          */
1329         public function getServerUptime() {
1330                 $vars = $this->getMysqlStatus( 'Uptime' );
1331
1332                 return (int)$vars['Uptime'];
1333         }
1334
1335         /**
1336          * Determines if the last failure was due to a deadlock
1337          *
1338          * @return bool
1339          */
1340         public function wasDeadlock() {
1341                 return $this->lastErrno() == 1213;
1342         }
1343
1344         /**
1345          * Determines if the last failure was due to a lock timeout
1346          *
1347          * @return bool
1348          */
1349         public function wasLockTimeout() {
1350                 return $this->lastErrno() == 1205;
1351         }
1352
1353         /**
1354          * Determines if the last failure was due to the database being read-only.
1355          *
1356          * @return bool
1357          */
1358         public function wasReadOnlyError() {
1359                 return $this->lastErrno() == 1223 ||
1360                         ( $this->lastErrno() == 1290 && strpos( $this->lastError(), '--read-only' ) !== false );
1361         }
1362
1363         public function wasConnectionError( $errno ) {
1364                 return $errno == 2013 || $errno == 2006;
1365         }
1366
1367         protected function wasKnownStatementRollbackError() {
1368                 $errno = $this->lastErrno();
1369
1370                 if ( $errno === 1205 ) { // lock wait timeout
1371                         // Note that this is uncached to avoid stale values of SET is used
1372                         $row = $this->selectRow(
1373                                 false,
1374                                 [ 'innodb_rollback_on_timeout' => '@@innodb_rollback_on_timeout' ],
1375                                 [],
1376                                 __METHOD__
1377                         );
1378                         // https://dev.mysql.com/doc/refman/5.7/en/innodb-error-handling.html
1379                         // https://dev.mysql.com/doc/refman/5.5/en/innodb-parameters.html
1380                         return $row->innodb_rollback_on_timeout ? false : true;
1381                 }
1382
1383                 // See https://dev.mysql.com/doc/refman/5.5/en/error-messages-server.html
1384                 return in_array( $errno, [ 1022, 1062, 1216, 1217, 1137, 1146, 1051, 1054 ], true );
1385         }
1386
1387         /**
1388          * @param string $oldName
1389          * @param string $newName
1390          * @param bool $temporary
1391          * @param string $fname
1392          * @return bool
1393          */
1394         public function duplicateTableStructure(
1395                 $oldName, $newName, $temporary = false, $fname = __METHOD__
1396         ) {
1397                 $tmp = $temporary ? 'TEMPORARY ' : '';
1398                 $newName = $this->addIdentifierQuotes( $newName );
1399                 $oldName = $this->addIdentifierQuotes( $oldName );
1400                 $query = "CREATE $tmp TABLE $newName (LIKE $oldName)";
1401
1402                 return $this->query( $query, $fname, $this::QUERY_PSEUDO_PERMANENT );
1403         }
1404
1405         /**
1406          * List all tables on the database
1407          *
1408          * @param string|null $prefix Only show tables with this prefix, e.g. mw_
1409          * @param string $fname Calling function name
1410          * @return array
1411          */
1412         public function listTables( $prefix = null, $fname = __METHOD__ ) {
1413                 $result = $this->query( "SHOW TABLES", $fname );
1414
1415                 $endArray = [];
1416
1417                 foreach ( $result as $table ) {
1418                         $vars = get_object_vars( $table );
1419                         $table = array_pop( $vars );
1420
1421                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1422                                 $endArray[] = $table;
1423                         }
1424                 }
1425
1426                 return $endArray;
1427         }
1428
1429         /**
1430          * @param string $tableName
1431          * @param string $fName
1432          * @return bool|IResultWrapper
1433          */
1434         public function dropTable( $tableName, $fName = __METHOD__ ) {
1435                 if ( !$this->tableExists( $tableName, $fName ) ) {
1436                         return false;
1437                 }
1438
1439                 return $this->query( "DROP TABLE IF EXISTS " . $this->tableName( $tableName ), $fName );
1440         }
1441
1442         /**
1443          * Get status information from SHOW STATUS in an associative array
1444          *
1445          * @param string $which
1446          * @return array
1447          */
1448         private function getMysqlStatus( $which = "%" ) {
1449                 $flags = self::QUERY_IGNORE_DBO_TRX;
1450                 $res = $this->query( "SHOW STATUS LIKE '{$which}'", __METHOD__, $flags );
1451                 $status = [];
1452
1453                 foreach ( $res as $row ) {
1454                         $status[$row->Variable_name] = $row->Value;
1455                 }
1456
1457                 return $status;
1458         }
1459
1460         /**
1461          * Lists VIEWs in the database
1462          *
1463          * @param string|null $prefix Only show VIEWs with this prefix, eg.
1464          * unit_test_, or $wgDBprefix. Default: null, would return all views.
1465          * @param string $fname Name of calling function
1466          * @return array
1467          * @since 1.22
1468          */
1469         public function listViews( $prefix = null, $fname = __METHOD__ ) {
1470                 // The name of the column containing the name of the VIEW
1471                 $propertyName = 'Tables_in_' . $this->getDBname();
1472
1473                 // Query for the VIEWS
1474                 $res = $this->query( 'SHOW FULL TABLES WHERE TABLE_TYPE = "VIEW"' );
1475                 $allViews = [];
1476                 foreach ( $res as $row ) {
1477                         array_push( $allViews, $row->$propertyName );
1478                 }
1479
1480                 if ( is_null( $prefix ) || $prefix === '' ) {
1481                         return $allViews;
1482                 }
1483
1484                 $filteredViews = [];
1485                 foreach ( $allViews as $viewName ) {
1486                         // Does the name of this VIEW start with the table-prefix?
1487                         if ( strpos( $viewName, $prefix ) === 0 ) {
1488                                 array_push( $filteredViews, $viewName );
1489                         }
1490                 }
1491
1492                 return $filteredViews;
1493         }
1494
1495         /**
1496          * Differentiates between a TABLE and a VIEW.
1497          *
1498          * @param string $name Name of the TABLE/VIEW to test
1499          * @param string|null $prefix
1500          * @return bool
1501          * @since 1.22
1502          */
1503         public function isView( $name, $prefix = null ) {
1504                 return in_array( $name, $this->listViews( $prefix ) );
1505         }
1506
1507         protected function isTransactableQuery( $sql ) {
1508                 return parent::isTransactableQuery( $sql ) &&
1509                         !preg_match( '/^SELECT\s+(GET|RELEASE|IS_FREE)_LOCK\(/', $sql );
1510         }
1511
1512         public function buildStringCast( $field ) {
1513                 return "CAST( $field AS BINARY )";
1514         }
1515
1516         /**
1517          * @param string $field Field or column to cast
1518          * @return string
1519          */
1520         public function buildIntegerCast( $field ) {
1521                 return 'CAST( ' . $field . ' AS SIGNED )';
1522         }
1523
1524         /*
1525          * @return bool Whether GTID support is used (mockable for testing)
1526          */
1527         protected function useGTIDs() {
1528                 return $this->useGTIDs;
1529         }
1530 }
1531
1532 /**
1533  * @deprecated since 1.29
1534  */
1535 class_alias( DatabaseMysqlBase::class, 'DatabaseMysqlBase' );