includes/libs/rdbms/database/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres 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 Wikimedia\Timestamp\ConvertibleTimestamp;
  26 use Wikimedia\WaitConditionLoop;
  27 use Wikimedia\AtEase\AtEase;
  28 use Exception;
  29
  30 /**
  31  * @ingroup Database
  32  */
  33 class DatabasePostgres extends Database {
  34         /** @var int|bool */
  35         protected $port;
  36
  37         /** @var resource */
  38         protected $lastResultHandle = null;
  39
  40         /** @var float|string */
  41         private $numericVersion = null;
  42         /** @var string Connect string to open a PostgreSQL connection */
  43         private $connectString;
  44         /** @var string */
  45         private $coreSchema;
  46         /** @var string */
  47         private $tempSchema;
  48         /** @var string[] Map of (reserved table name => alternate table name) */
  49         private $keywordTableMap = [];
  50
  51         /**
  52          * @see Database::__construct()
  53          * @param array $params Additional parameters include:
  54          *   - keywordTableMap : Map of reserved table names to alternative table names to use
  55          */
  56         public function __construct( array $params ) {
  57                 $this->port = $params['port'] ?? false;
  58                 $this->keywordTableMap = $params['keywordTableMap'] ?? [];
  59
  60                 parent::__construct( $params );
  61         }
  62
  63         public function getType() {
  64                 return 'postgres';
  65         }
  66
  67         public function implicitGroupby() {
  68                 return false;
  69         }
  70
  71         public function implicitOrderby() {
  72                 return false;
  73         }
  74
  75         public function hasConstraint( $name ) {
  76                 foreach ( $this->getCoreSchemas() as $schema ) {
  77                         $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
  78                                 "WHERE c.connamespace = n.oid AND conname = " .
  79                                 $this->addQuotes( $name ) . " AND n.nspname = " .
  80                                 $this->addQuotes( $schema );
  81                         $res = $this->doQuery( $sql );
  82                         if ( $res && $this->numRows( $res ) ) {
  83                                 return true;
  84                         }
  85                 }
  86                 return false;
  87         }
  88
  89         protected function open( $server, $user, $password, $dbName, $schema, $tablePrefix ) {
  90                 // Test for Postgres support, to avoid suppressed fatal error
  91                 if ( !function_exists( 'pg_connect' ) ) {
  92                         throw new DBConnectionError(
  93                                 $this,
  94                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
  95                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
  96                                 "webserver and database)\n"
  97                         );
  98                 }
  99
 100                 $this->close();
 101
 102                 $this->server = $server;
 103                 $this->user = $user;
 104                 $this->password = $password;
 105
 106                 $connectVars = [
 107                         // pg_connect() user $user as the default database. Since a database is *required*,
 108                         // at least pick a "don't care" database that is more likely to exist. This case
 109                         // arrises when LoadBalancer::getConnection( $i, [], '' ) is used.
 110                         'dbname' => strlen( $dbName ) ? $dbName : 'postgres',
 111                         'user' => $user,
 112                         'password' => $password
 113                 ];
 114                 if ( $server != false && $server != '' ) {
 115                         $connectVars['host'] = $server;
 116                 }
 117                 if ( (int)$this->port > 0 ) {
 118                         $connectVars['port'] = (int)$this->port;
 119                 }
 120                 if ( $this->flags & self::DBO_SSL ) {
 121                         $connectVars['sslmode'] = 'require';
 122                 }
 123
 124                 $this->connectString = $this->makeConnectionString( $connectVars );
 125
 126                 $this->installErrorHandler();
 127                 try {
 128                         // Use new connections to let LoadBalancer/LBFactory handle reuse
 129                         $this->conn = pg_connect( $this->connectString, PGSQL_CONNECT_FORCE_NEW );
 130                 } catch ( Exception $ex ) {
 131                         $this->restoreErrorHandler();
 132                         throw $ex;
 133                 }
 134                 $phpError = $this->restoreErrorHandler();
 135
 136                 if ( !$this->conn ) {
 137                         $this->queryLogger->debug(
 138                                 "DB connection error\n" .
 139                                 "Server: $server, Database: $dbName, User: $user, Password: " .
 140                                 substr( $password, 0, 3 ) . "...\n"
 141                         );
 142                         $this->queryLogger->debug( $this->lastError() . "\n" );
 143                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 144                 }
 145
 146                 try {
 147                         // If called from the command-line (e.g. importDump), only show errors.
 148                         // No transaction should be open at this point, so the problem of the SET
 149                         // effects being rolled back should not be an issue.
 150                         // See https://www.postgresql.org/docs/8.3/sql-set.html
 151                         $variables = [];
 152                         if ( $this->cliMode ) {
 153                                 $variables['client_min_messages'] = 'ERROR';
 154                         }
 155                         $variables += [
 156                                 'client_encoding' => 'UTF8',
 157                                 'datestyle' => 'ISO, YMD',
 158                                 'timezone' => 'GMT',
 159                                 'standard_conforming_strings' => 'on',
 160                                 'bytea_output' => 'escape'
 161                         ];
 162                         foreach ( $variables as $var => $val ) {
 163                                 $this->query(
 164                                         'SET ' . $this->addIdentifierQuotes( $var ) . ' = ' . $this->addQuotes( $val ),
 165                                         __METHOD__,
 166                                         self::QUERY_IGNORE_DBO_TRX | self::QUERY_NO_RETRY
 167                                 );
 168                         }
 169
 170                         $this->determineCoreSchema( $schema );
 171                         $this->currentDomain = new DatabaseDomain( $dbName, $schema, $tablePrefix );
 172                 } catch ( Exception $e ) {
 173                         // Connection was not fully initialized and is not safe for use
 174                         $this->conn = false;
 175                 }
 176         }
 177
 178         protected function relationSchemaQualifier() {
 179                 if ( $this->coreSchema === $this->currentDomain->getSchema() ) {
 180                         // The schema to be used is now in the search path; no need for explicit qualification
 181                         return '';
 182                 }
 183
 184                 return parent::relationSchemaQualifier();
 185         }
 186
 187         public function databasesAreIndependent() {
 188                 return true;
 189         }
 190
 191         public function doSelectDomain( DatabaseDomain $domain ) {
 192                 if ( $this->getDBname() !== $domain->getDatabase() ) {
 193                         // Postgres doesn't support selectDB in the same way MySQL does.
 194                         // So if the DB name doesn't match the open connection, open a new one
 195                         $this->open(
 196                                 $this->server,
 197                                 $this->user,
 198                                 $this->password,
 199                                 $domain->getDatabase(),
 200                                 $domain->getSchema(),
 201                                 $domain->getTablePrefix()
 202                         );
 203                 } else {
 204                         $this->currentDomain = $domain;
 205                 }
 206
 207                 return true;
 208         }
 209
 210         /**
 211          * @param string[] $vars
 212          * @return string
 213          */
 214         private function makeConnectionString( $vars ) {
 215                 $s = '';
 216                 foreach ( $vars as $name => $value ) {
 217                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 218                 }
 219
 220                 return $s;
 221         }
 222
 223         protected function closeConnection() {
 224                 return $this->conn ? pg_close( $this->conn ) : true;
 225         }
 226
 227         protected function isTransactableQuery( $sql ) {
 228                 return parent::isTransactableQuery( $sql ) &&
 229                         !preg_match( '/^SELECT\s+pg_(try_|)advisory_\w+\(/', $sql );
 230         }
 231
 232         /**
 233          * @param string $sql
 234          * @return bool|mixed|resource
 235          */
 236         public function doQuery( $sql ) {
 237                 $conn = $this->getBindingHandle();
 238
 239                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 240                 // Clear previously left over PQresult
 241                 while ( $res = pg_get_result( $conn ) ) {
 242                         pg_free_result( $res );
 243                 }
 244                 if ( pg_send_query( $conn, $sql ) === false ) {
 245                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 246                 }
 247                 $this->lastResultHandle = pg_get_result( $conn );
 248                 if ( pg_result_error( $this->lastResultHandle ) ) {
 249                         return false;
 250                 }
 251
 252                 return $this->lastResultHandle;
 253         }
 254
 255         protected function dumpError() {
 256                 $diags = [
 257                         PGSQL_DIAG_SEVERITY,
 258                         PGSQL_DIAG_SQLSTATE,
 259                         PGSQL_DIAG_MESSAGE_PRIMARY,
 260                         PGSQL_DIAG_MESSAGE_DETAIL,
 261                         PGSQL_DIAG_MESSAGE_HINT,
 262                         PGSQL_DIAG_STATEMENT_POSITION,
 263                         PGSQL_DIAG_INTERNAL_POSITION,
 264                         PGSQL_DIAG_INTERNAL_QUERY,
 265                         PGSQL_DIAG_CONTEXT,
 266                         PGSQL_DIAG_SOURCE_FILE,
 267                         PGSQL_DIAG_SOURCE_LINE,
 268                         PGSQL_DIAG_SOURCE_FUNCTION
 269                 ];
 270                 foreach ( $diags as $d ) {
 271                         $this->queryLogger->debug( sprintf( "PgSQL ERROR(%d): %s\n",
 272                                 $d, pg_result_error_field( $this->lastResultHandle, $d ) ) );
 273                 }
 274         }
 275
 276         public function freeResult( $res ) {
 277                 AtEase::suppressWarnings();
 278                 $ok = pg_free_result( ResultWrapper::unwrap( $res ) );
 279                 AtEase::restoreWarnings();
 280                 if ( !$ok ) {
 281                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 282                 }
 283         }
 284
 285         public function fetchObject( $res ) {
 286                 AtEase::suppressWarnings();
 287                 $row = pg_fetch_object( ResultWrapper::unwrap( $res ) );
 288                 AtEase::restoreWarnings();
 289                 # @todo FIXME: HACK HACK HACK HACK debug
 290
 291                 # @todo hashar: not sure if the following test really trigger if the object
 292                 #          fetching failed.
 293                 $conn = $this->getBindingHandle();
 294                 if ( pg_last_error( $conn ) ) {
 295                         throw new DBUnexpectedError(
 296                                 $this,
 297                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 298                         );
 299                 }
 300
 301                 return $row;
 302         }
 303
 304         public function fetchRow( $res ) {
 305                 AtEase::suppressWarnings();
 306                 $row = pg_fetch_array( ResultWrapper::unwrap( $res ) );
 307                 AtEase::restoreWarnings();
 308
 309                 $conn = $this->getBindingHandle();
 310                 if ( pg_last_error( $conn ) ) {
 311                         throw new DBUnexpectedError(
 312                                 $this,
 313                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 314                         );
 315                 }
 316
 317                 return $row;
 318         }
 319
 320         public function numRows( $res ) {
 321                 if ( $res === false ) {
 322                         return 0;
 323                 }
 324
 325                 AtEase::suppressWarnings();
 326                 $n = pg_num_rows( ResultWrapper::unwrap( $res ) );
 327                 AtEase::restoreWarnings();
 328
 329                 $conn = $this->getBindingHandle();
 330                 if ( pg_last_error( $conn ) ) {
 331                         throw new DBUnexpectedError(
 332                                 $this,
 333                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 334                         );
 335                 }
 336
 337                 return $n;
 338         }
 339
 340         public function numFields( $res ) {
 341                 return pg_num_fields( ResultWrapper::unwrap( $res ) );
 342         }
 343
 344         public function fieldName( $res, $n ) {
 345                 return pg_field_name( ResultWrapper::unwrap( $res ), $n );
 346         }
 347
 348         public function insertId() {
 349                 $res = $this->query( "SELECT lastval()" );
 350                 $row = $this->fetchRow( $res );
 351                 return is_null( $row[0] ) ? null : (int)$row[0];
 352         }
 353
 354         public function dataSeek( $res, $row ) {
 355                 return pg_result_seek( ResultWrapper::unwrap( $res ), $row );
 356         }
 357
 358         public function lastError() {
 359                 if ( $this->conn ) {
 360                         if ( $this->lastResultHandle ) {
 361                                 return pg_result_error( $this->lastResultHandle );
 362                         } else {
 363                                 return pg_last_error();
 364                         }
 365                 }
 366
 367                 return $this->getLastPHPError() ?: 'No database connection';
 368         }
 369
 370         public function lastErrno() {
 371                 if ( $this->lastResultHandle ) {
 372                         return pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
 373                 } else {
 374                         return false;
 375                 }
 376         }
 377
 378         protected function fetchAffectedRowCount() {
 379                 if ( !$this->lastResultHandle ) {
 380                         return 0;
 381                 }
 382
 383                 return pg_affected_rows( $this->lastResultHandle );
 384         }
 385
 386         /**
 387          * Estimate rows in dataset
 388          * Returns estimated count, based on EXPLAIN output
 389          * This is not necessarily an accurate estimate, so use sparingly
 390          * Returns -1 if count cannot be found
 391          * Takes same arguments as Database::select()
 392          *
 393          * @param string $table
 394          * @param string $var
 395          * @param string $conds
 396          * @param string $fname
 397          * @param array $options
 398          * @param array $join_conds
 399          * @return int
 400          */
 401         public function estimateRowCount( $table, $var = '*', $conds = '',
 402                 $fname = __METHOD__, $options = [], $join_conds = []
 403         ) {
 404                 $conds = $this->normalizeConditions( $conds, $fname );
 405                 $column = $this->extractSingleFieldFromList( $var );
 406                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 407                         $conds[] = "$column IS NOT NULL";
 408                 }
 409
 410                 $options['EXPLAIN'] = true;
 411                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 412                 $rows = -1;
 413                 if ( $res ) {
 414                         $row = $this->fetchRow( $res );
 415                         $count = [];
 416                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 417                                 $rows = (int)$count[1];
 418                         }
 419                 }
 420
 421                 return $rows;
 422         }
 423
 424         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 425                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 426                 $res = $this->query( $sql, $fname );
 427                 if ( !$res ) {
 428                         return null;
 429                 }
 430                 foreach ( $res as $row ) {
 431                         if ( $row->indexname == $this->indexName( $index ) ) {
 432                                 return $row;
 433                         }
 434                 }
 435
 436                 return false;
 437         }
 438
 439         public function indexAttributes( $index, $schema = false ) {
 440                 if ( $schema === false ) {
 441                         $schemas = $this->getCoreSchemas();
 442                 } else {
 443                         $schemas = [ $schema ];
 444                 }
 445
 446                 $eindex = $this->addQuotes( $index );
 447
 448                 foreach ( $schemas as $schema ) {
 449                         $eschema = $this->addQuotes( $schema );
 450                         /*
 451                          * A subquery would be not needed if we didn't care about the order
 452                          * of attributes, but we do
 453                          */
 454                         $sql = <<<__INDEXATTR__
 455
 456                                 SELECT opcname,
 457                                         attname,
 458                                         i.indoption[s.g] as option,
 459                                         pg_am.amname
 460                                 FROM
 461                                         (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 462                                                 FROM
 463                                                         pg_index isub
 464                                                 JOIN pg_class cis
 465                                                         ON cis.oid=isub.indexrelid
 466                                                 JOIN pg_namespace ns
 467                                                         ON cis.relnamespace = ns.oid
 468                                                 WHERE cis.relname=$eindex AND ns.nspname=$eschema) AS s,
 469                                         pg_attribute,
 470                                         pg_opclass opcls,
 471                                         pg_am,
 472                                         pg_class ci
 473                                         JOIN pg_index i
 474                                                 ON ci.oid=i.indexrelid
 475                                         JOIN pg_class ct
 476                                                 ON ct.oid = i.indrelid
 477                                         JOIN pg_namespace n
 478                                                 ON ci.relnamespace = n.oid
 479                                         WHERE
 480                                                 ci.relname=$eindex AND n.nspname=$eschema
 481                                                 AND     attrelid = ct.oid
 482                                                 AND     i.indkey[s.g] = attnum
 483                                                 AND     i.indclass[s.g] = opcls.oid
 484                                                 AND     pg_am.oid = opcls.opcmethod
 485 __INDEXATTR__;
 486                         $res = $this->query( $sql, __METHOD__ );
 487                         $a = [];
 488                         if ( $res ) {
 489                                 foreach ( $res as $row ) {
 490                                         $a[] = [
 491                                                 $row->attname,
 492                                                 $row->opcname,
 493                                                 $row->amname,
 494                                                 $row->option ];
 495                                 }
 496                                 return $a;
 497                         }
 498                 }
 499                 return null;
 500         }
 501
 502         public function indexUnique( $table, $index, $fname = __METHOD__ ) {
 503                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 504                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 505                         $this->strencode( $this->indexName( $index ) ) .
 506                         ")'";
 507                 $res = $this->query( $sql, $fname );
 508                 if ( !$res ) {
 509                         return null;
 510                 }
 511
 512                 return $res->numRows() > 0;
 513         }
 514
 515         public function selectSQLText(
 516                 $table, $vars, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
 517         ) {
 518                 if ( is_string( $options ) ) {
 519                         $options = [ $options ];
 520                 }
 521
 522                 // Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 523                 // to the parent function to get the actual SQL text.
 524                 // In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 525                 // can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to
 526                 // do so causes a DB error. This wrapper checks which tables can be locked and adjusts it
 527                 // accordingly.
 528                 // MySQL uses "ORDER BY NULL" as an optimization hint, but that is illegal in PostgreSQL.
 529                 if ( is_array( $options ) ) {
 530                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 531                         if ( $forUpdateKey !== false && $join_conds ) {
 532                                 unset( $options[$forUpdateKey] );
 533                                 $options['FOR UPDATE'] = [];
 534
 535                                 $toCheck = $table;
 536                                 reset( $toCheck );
 537                                 while ( $toCheck ) {
 538                                         $alias = key( $toCheck );
 539                                         $name = $toCheck[$alias];
 540                                         unset( $toCheck[$alias] );
 541
 542                                         $hasAlias = !is_numeric( $alias );
 543                                         if ( !$hasAlias && is_string( $name ) ) {
 544                                                 $alias = $name;
 545                                         }
 546
 547                                         if ( !isset( $join_conds[$alias] ) ||
 548                                                 !preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_conds[$alias][0] )
 549                                         ) {
 550                                                 if ( is_array( $name ) ) {
 551                                                         // It's a parenthesized group, process all the tables inside the group.
 552                                                         $toCheck = array_merge( $toCheck, $name );
 553                                                 } else {
 554                                                         // Quote alias names so $this->tableName() won't mangle them
 555                                                         $options['FOR UPDATE'][] = $hasAlias ? $this->addIdentifierQuotes( $alias ) : $alias;
 556                                                 }
 557                                         }
 558                                 }
 559                         }
 560
 561                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 562                                 unset( $options['ORDER BY'] );
 563                         }
 564                 }
 565
 566                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 567         }
 568
 569         /** @inheritDoc */
 570         public function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 571                 if ( !count( $args ) ) {
 572                         return true;
 573                 }
 574
 575                 $table = $this->tableName( $table );
 576                 if ( !isset( $this->numericVersion ) ) {
 577                         $this->getServerVersion();
 578                 }
 579
 580                 if ( !is_array( $options ) ) {
 581                         $options = [ $options ];
 582                 }
 583
 584                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 585                         $rows = $args;
 586                         $keys = array_keys( $args[0] );
 587                 } else {
 588                         $rows = [ $args ];
 589                         $keys = array_keys( $args );
 590                 }
 591
 592                 $ignore = in_array( 'IGNORE', $options );
 593
 594                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 595
 596                 if ( $this->numericVersion >= 9.5 || !$ignore ) {
 597                         // No IGNORE or our PG has "ON CONFLICT DO NOTHING"
 598                         $first = true;
 599                         foreach ( $rows as $row ) {
 600                                 if ( $first ) {
 601                                         $first = false;
 602                                 } else {
 603                                         $sql .= ',';
 604                                 }
 605                                 $sql .= '(' . $this->makeList( $row ) . ')';
 606                         }
 607                         if ( $ignore ) {
 608                                 $sql .= ' ON CONFLICT DO NOTHING';
 609                         }
 610                         $this->query( $sql, $fname );
 611                 } else {
 612                         // Emulate IGNORE by doing each row individually, with savepoints
 613                         // to roll back as necessary.
 614                         $numrowsinserted = 0;
 615
 616                         $tok = $this->startAtomic( "$fname (outer)", self::ATOMIC_CANCELABLE );
 617                         try {
 618                                 foreach ( $rows as $row ) {
 619                                         $tempsql = $sql;
 620                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 621
 622                                         $this->startAtomic( "$fname (inner)", self::ATOMIC_CANCELABLE );
 623                                         try {
 624                                                 $this->query( $tempsql, $fname );
 625                                                 $this->endAtomic( "$fname (inner)" );
 626                                                 $numrowsinserted++;
 627                                         } catch ( DBQueryError $e ) {
 628                                                 $this->cancelAtomic( "$fname (inner)" );
 629                                                 // Our IGNORE is supposed to ignore duplicate key errors, but not others.
 630                                                 // (even though MySQL's version apparently ignores all errors)
 631                                                 if ( $e->errno !== '23505' ) {
 632                                                         throw $e;
 633                                                 }
 634                                         }
 635                                 }
 636                         } catch ( Exception $e ) {
 637                                 $this->cancelAtomic( "$fname (outer)", $tok );
 638                                 throw $e;
 639                         }
 640                         $this->endAtomic( "$fname (outer)" );
 641
 642                         // Set the affected row count for the whole operation
 643                         $this->affectedRowCount = $numrowsinserted;
 644                 }
 645
 646                 return true;
 647         }
 648
 649         protected function makeUpdateOptionsArray( $options ) {
 650                 if ( !is_array( $options ) ) {
 651                         $options = [ $options ];
 652                 }
 653
 654                 // PostgreSQL doesn't support anything like "ignore" for
 655                 // UPDATE.
 656                 $options = array_diff( $options, [ 'IGNORE' ] );
 657
 658                 return parent::makeUpdateOptionsArray( $options );
 659         }
 660
 661         /**
 662          * INSERT SELECT wrapper
 663          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 664          * Source items may be literals rather then field names, but strings should
 665          * be quoted with Database::addQuotes()
 666          * $conds may be "*" to copy the whole table
 667          * srcTable may be an array of tables.
 668          * @todo FIXME: Implement this a little better (separate select/insert)?
 669          *
 670          * @param string $destTable
 671          * @param array|string $srcTable
 672          * @param array $varMap
 673          * @param array $conds
 674          * @param string $fname
 675          * @param array $insertOptions
 676          * @param array $selectOptions
 677          * @param array $selectJoinConds
 678          */
 679         protected function nativeInsertSelect(
 680                 $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 681                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 682         ) {
 683                 if ( !is_array( $insertOptions ) ) {
 684                         $insertOptions = [ $insertOptions ];
 685                 }
 686
 687                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 688                         if ( $this->getServerVersion() >= 9.5 ) {
 689                                 // Use ON CONFLICT DO NOTHING if we have it for IGNORE
 690                                 $destTable = $this->tableName( $destTable );
 691
 692                                 $selectSql = $this->selectSQLText(
 693                                         $srcTable,
 694                                         array_values( $varMap ),
 695                                         $conds,
 696                                         $fname,
 697                                         $selectOptions,
 698                                         $selectJoinConds
 699                                 );
 700
 701                                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ') ' .
 702                                         $selectSql . ' ON CONFLICT DO NOTHING';
 703
 704                                 $this->query( $sql, $fname );
 705                         } else {
 706                                 // IGNORE and we don't have ON CONFLICT DO NOTHING, so just use the non-native version
 707                                 $this->nonNativeInsertSelect(
 708                                         $destTable, $srcTable, $varMap, $conds, $fname,
 709                                         $insertOptions, $selectOptions, $selectJoinConds
 710                                 );
 711                         }
 712                 } else {
 713                         parent::nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname,
 714                                 $insertOptions, $selectOptions, $selectJoinConds );
 715                 }
 716         }
 717
 718         public function tableName( $name, $format = 'quoted' ) {
 719                 // Replace reserved words with better ones
 720                 $name = $this->remappedTableName( $name );
 721
 722                 return parent::tableName( $name, $format );
 723         }
 724
 725         /**
 726          * @param string $name
 727          * @return string Value of $name or remapped name if $name is a reserved keyword
 728          */
 729         public function remappedTableName( $name ) {
 730                 return $this->keywordTableMap[$name] ?? $name;
 731         }
 732
 733         /**
 734          * @param string $name
 735          * @param string $format
 736          * @return string Qualified and encoded (if requested) table name
 737          */
 738         public function realTableName( $name, $format = 'quoted' ) {
 739                 return parent::tableName( $name, $format );
 740         }
 741
 742         public function nextSequenceValue( $seqName ) {
 743                 return new NextSequenceValue;
 744         }
 745
 746         /**
 747          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 748          *
 749          * @param string $seqName
 750          * @return int
 751          */
 752         public function currentSequenceValue( $seqName ) {
 753                 $safeseq = str_replace( "'", "''", $seqName );
 754                 $res = $this->query( "SELECT currval('$safeseq')" );
 755                 $row = $this->fetchRow( $res );
 756                 $currval = $row[0];
 757
 758                 return $currval;
 759         }
 760
 761         public function textFieldSize( $table, $field ) {
 762                 $table = $this->tableName( $table );
 763                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 764                         FROM pg_class c, pg_attribute a, pg_type t
 765                         WHERE relname='$table' AND a.attrelid=c.oid AND
 766                                 a.atttypid=t.oid and a.attname='$field'";
 767                 $res = $this->query( $sql );
 768                 $row = $this->fetchObject( $res );
 769                 if ( $row->ftype == 'varchar' ) {
 770                         $size = $row->size - 4;
 771                 } else {
 772                         $size = $row->size;
 773                 }
 774
 775                 return $size;
 776         }
 777
 778         public function limitResult( $sql, $limit, $offset = false ) {
 779                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 780         }
 781
 782         public function wasDeadlock() {
 783                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 784                 return $this->lastErrno() === '40P01';
 785         }
 786
 787         public function wasLockTimeout() {
 788                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 789                 return $this->lastErrno() === '55P03';
 790         }
 791
 792         public function wasConnectionError( $errno ) {
 793                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 794                 static $codes = [ '08000', '08003', '08006', '08001', '08004', '57P01', '57P03', '53300' ];
 795
 796                 return in_array( $errno, $codes, true );
 797         }
 798
 799         protected function wasKnownStatementRollbackError() {
 800                 return false; // transaction has to be rolled-back from error state
 801         }
 802
 803         public function duplicateTableStructure(
 804                 $oldName, $newName, $temporary = false, $fname = __METHOD__
 805         ) {
 806                 $newNameE = $this->addIdentifierQuotes( $newName );
 807                 $oldNameE = $this->addIdentifierQuotes( $oldName );
 808
 809                 $temporary = $temporary ? 'TEMPORARY' : '';
 810
 811                 $ret = $this->query(
 812                         "CREATE $temporary TABLE $newNameE " .
 813                                 "(LIKE $oldNameE INCLUDING DEFAULTS INCLUDING INDEXES)",
 814                         $fname,
 815                         $this::QUERY_PSEUDO_PERMANENT
 816                 );
 817                 if ( !$ret ) {
 818                         return $ret;
 819                 }
 820
 821                 $res = $this->query( 'SELECT attname FROM pg_class c'
 822                         . ' JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 823                         . ' JOIN pg_attribute a ON (a.attrelid = c.oid)'
 824                         . ' JOIN pg_attrdef d ON (c.oid=d.adrelid and a.attnum=d.adnum)'
 825                         . ' WHERE relkind = \'r\''
 826                         . ' AND nspname = ' . $this->addQuotes( $this->getCoreSchema() )
 827                         . ' AND relname = ' . $this->addQuotes( $oldName )
 828                         . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 829                         $fname
 830                 );
 831                 $row = $this->fetchObject( $res );
 832                 if ( $row ) {
 833                         $field = $row->attname;
 834                         $newSeq = "{$newName}_{$field}_seq";
 835                         $fieldE = $this->addIdentifierQuotes( $field );
 836                         $newSeqE = $this->addIdentifierQuotes( $newSeq );
 837                         $newSeqQ = $this->addQuotes( $newSeq );
 838                         $this->query(
 839                                 "CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE",
 840                                 $fname
 841                         );
 842                         $this->query(
 843                                 "ALTER TABLE $newNameE ALTER COLUMN $fieldE SET DEFAULT nextval({$newSeqQ}::regclass)",
 844                                 $fname
 845                         );
 846                 }
 847
 848                 return $ret;
 849         }
 850
 851         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
 852                 $table = $this->tableName( $table, 'raw' );
 853                 foreach ( $this->getCoreSchemas() as $schema ) {
 854                         $res = $this->query(
 855                                 'SELECT c.oid FROM pg_class c JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 856                                 . ' WHERE relkind = \'r\''
 857                                 . ' AND nspname = ' . $this->addQuotes( $schema )
 858                                 . ' AND relname = ' . $this->addQuotes( $table ),
 859                                 $fname
 860                         );
 861                         if ( !$res || !$this->numRows( $res ) ) {
 862                                 continue;
 863                         }
 864
 865                         $oid = $this->fetchObject( $res )->oid;
 866                         $res = $this->query( 'SELECT pg_get_expr(adbin, adrelid) AS adsrc FROM pg_attribute a'
 867                                 . ' JOIN pg_attrdef d ON (a.attrelid=d.adrelid and a.attnum=d.adnum)'
 868                                 . " WHERE a.attrelid = $oid"
 869                                 . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 870                                 $fname
 871                         );
 872                         $row = $this->fetchObject( $res );
 873                         if ( $row ) {
 874                                 $this->query(
 875                                         'SELECT ' . preg_replace( '/^nextval\((.+)\)$/', 'setval($1,1,false)', $row->adsrc ),
 876                                         $fname
 877                                 );
 878                                 return true;
 879                         }
 880                         return false;
 881                 }
 882
 883                 return false;
 884         }
 885
 886         /**
 887          * @param string $prefix Only show tables with this prefix, e.g. mw_
 888          * @param string $fname Calling function name
 889          * @return string[]
 890          * @suppress SecurityCheck-SQLInjection array_map not recognized T204911
 891          */
 892         public function listTables( $prefix = '', $fname = __METHOD__ ) {
 893                 $eschemas = implode( ',', array_map( [ $this, 'addQuotes' ], $this->getCoreSchemas() ) );
 894                 $result = $this->query(
 895                         "SELECT DISTINCT tablename FROM pg_tables WHERE schemaname IN ($eschemas)", $fname );
 896                 $endArray = [];
 897
 898                 foreach ( $result as $table ) {
 899                         $vars = get_object_vars( $table );
 900                         $table = array_pop( $vars );
 901                         if ( $prefix == '' || strpos( $table, $prefix ) === 0 ) {
 902                                 $endArray[] = $table;
 903                         }
 904                 }
 905
 906                 return $endArray;
 907         }
 908
 909         public function timestamp( $ts = 0 ) {
 910                 $ct = new ConvertibleTimestamp( $ts );
 911
 912                 return $ct->getTimestamp( TS_POSTGRES );
 913         }
 914
 915         /**
 916          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
 917          * to https://www.php.net/manual/en/ref.pgsql.php
 918          *
 919          * Parsing a postgres array can be a tricky problem, he's my
 920          * take on this, it handles multi-dimensional arrays plus
 921          * escaping using a nasty regexp to determine the limits of each
 922          * data-item.
 923          *
 924          * This should really be handled by PHP PostgreSQL module
 925          *
 926          * @since 1.19
 927          * @param string $text Postgreql array returned in a text form like {a,b}
 928          * @param string[] $output
 929          * @param int|bool $limit
 930          * @param int $offset
 931          * @return string[]
 932          */
 933         private function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
 934                 if ( $limit === false ) {
 935                         $limit = strlen( $text ) - 1;
 936                         $output = [];
 937                 }
 938                 if ( $text == '{}' ) {
 939                         return $output;
 940                 }
 941                 do {
 942                         if ( $text[$offset] != '{' ) {
 943                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
 944                                         $text, $match, 0, $offset );
 945                                 $offset += strlen( $match[0] );
 946                                 $output[] = ( $match[1][0] != '"'
 947                                         ? $match[1]
 948                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
 949                                 if ( $match[3] == '},' ) {
 950                                         return $output;
 951                                 }
 952                         } else {
 953                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
 954                         }
 955                 } while ( $limit > $offset );
 956
 957                 return $output;
 958         }
 959
 960         public function aggregateValue( $valuedata, $valuename = 'value' ) {
 961                 return $valuedata;
 962         }
 963
 964         public function getSoftwareLink() {
 965                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
 966         }
 967
 968         /**
 969          * Return current schema (executes SELECT current_schema())
 970          * Needs transaction
 971          *
 972          * @since 1.19
 973          * @return string Default schema for the current session
 974          */
 975         public function getCurrentSchema() {
 976                 $res = $this->query( "SELECT current_schema()", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 977                 $row = $this->fetchRow( $res );
 978
 979                 return $row[0];
 980         }
 981
 982         /**
 983          * Return list of schemas which are accessible without schema name
 984          * This is list does not contain magic keywords like "$user"
 985          * Needs transaction
 986          *
 987          * @see getSearchPath()
 988          * @see setSearchPath()
 989          * @since 1.19
 990          * @return array List of actual schemas for the current sesson
 991          */
 992         public function getSchemas() {
 993                 $res = $this->query(
 994                         "SELECT current_schemas(false)",
 995                         __METHOD__,
 996                         self::QUERY_IGNORE_DBO_TRX
 997                 );
 998                 $row = $this->fetchRow( $res );
 999                 $schemas = [];
1000
1001                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1002
1003                 return $this->pg_array_parse( $row[0], $schemas );
1004         }
1005
1006         /**
1007          * Return search patch for schemas
1008          * This is different from getSchemas() since it contain magic keywords
1009          * (like "$user").
1010          * Needs transaction
1011          *
1012          * @since 1.19
1013          * @return array How to search for table names schemas for the current user
1014          */
1015         public function getSearchPath() {
1016                 $res = $this->query( "SHOW search_path", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
1017                 $row = $this->fetchRow( $res );
1018
1019                 /* PostgreSQL returns SHOW values as strings */
1020
1021                 return explode( ",", $row[0] );
1022         }
1023
1024         /**
1025          * Update search_path, values should already be sanitized
1026          * Values may contain magic keywords like "$user"
1027          * @since 1.19
1028          *
1029          * @param array $search_path List of schemas to be searched by default
1030          */
1031         private function setSearchPath( $search_path ) {
1032                 $this->query(
1033                         "SET search_path = " . implode( ", ", $search_path ),
1034                         __METHOD__,
1035                         self::QUERY_IGNORE_DBO_TRX
1036                 );
1037         }
1038
1039         /**
1040          * Determine default schema for the current application
1041          * Adjust this session schema search path if desired schema exists
1042          * and is not alread there.
1043          *
1044          * We need to have name of the core schema stored to be able
1045          * to query database metadata.
1046          *
1047          * This will be also called by the installer after the schema is created
1048          *
1049          * @since 1.19
1050          *
1051          * @param string $desiredSchema
1052          */
1053         public function determineCoreSchema( $desiredSchema ) {
1054                 if ( $this->trxLevel() ) {
1055                         // We do not want the schema selection to change on ROLLBACK or INSERT SELECT.
1056                         // See https://www.postgresql.org/docs/8.3/sql-set.html
1057                         throw new DBUnexpectedError(
1058                                 $this,
1059                                 __METHOD__ . ": a transaction is currently active"
1060                         );
1061                 }
1062
1063                 if ( $this->schemaExists( $desiredSchema ) ) {
1064                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1065                                 $this->coreSchema = $desiredSchema;
1066                                 $this->queryLogger->debug(
1067                                         "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1068                         } else {
1069                                 /**
1070                                  * Prepend our schema (e.g. 'mediawiki') in front
1071                                  * of the search path
1072                                  * Fixes T17816
1073                                  */
1074                                 $search_path = $this->getSearchPath();
1075                                 array_unshift( $search_path, $this->addIdentifierQuotes( $desiredSchema ) );
1076                                 $this->setSearchPath( $search_path );
1077                                 $this->coreSchema = $desiredSchema;
1078                                 $this->queryLogger->debug(
1079                                         "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1080                         }
1081                 } else {
1082                         $this->coreSchema = $this->getCurrentSchema();
1083                         $this->queryLogger->debug(
1084                                 "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1085                                 $this->coreSchema . "\"\n" );
1086                 }
1087         }
1088
1089         /**
1090          * Return schema name for core application tables
1091          *
1092          * @since 1.19
1093          * @return string Core schema name
1094          */
1095         public function getCoreSchema() {
1096                 return $this->coreSchema;
1097         }
1098
1099         /**
1100          * Return schema names for temporary tables and core application tables
1101          *
1102          * @since 1.31
1103          * @return string[] schema names
1104          */
1105         public function getCoreSchemas() {
1106                 if ( $this->tempSchema ) {
1107                         return [ $this->tempSchema, $this->getCoreSchema() ];
1108                 }
1109
1110                 $res = $this->query(
1111                         "SELECT nspname FROM pg_catalog.pg_namespace n WHERE n.oid = pg_my_temp_schema()", __METHOD__
1112                 );
1113                 $row = $this->fetchObject( $res );
1114                 if ( $row ) {
1115                         $this->tempSchema = $row->nspname;
1116                         return [ $this->tempSchema, $this->getCoreSchema() ];
1117                 }
1118
1119                 return [ $this->getCoreSchema() ];
1120         }
1121
1122         public function getServerVersion() {
1123                 if ( !isset( $this->numericVersion ) ) {
1124                         $conn = $this->getBindingHandle();
1125                         $versionInfo = pg_version( $conn );
1126                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1127                                 // Old client, abort install
1128                                 $this->numericVersion = '7.3 or earlier';
1129                         } elseif ( isset( $versionInfo['server'] ) ) {
1130                                 // Normal client
1131                                 $this->numericVersion = $versionInfo['server'];
1132                         } else {
1133                                 // T18937: broken pgsql extension from PHP<5.3
1134                                 $this->numericVersion = pg_parameter_status( $conn, 'server_version' );
1135                         }
1136                 }
1137
1138                 return $this->numericVersion;
1139         }
1140
1141         /**
1142          * Query whether a given relation exists (in the given schema, or the
1143          * default mw one if not given)
1144          * @param string $table
1145          * @param array|string $types
1146          * @param bool|string $schema
1147          * @return bool
1148          */
1149         private function relationExists( $table, $types, $schema = false ) {
1150                 if ( !is_array( $types ) ) {
1151                         $types = [ $types ];
1152                 }
1153                 if ( $schema === false ) {
1154                         $schemas = $this->getCoreSchemas();
1155                 } else {
1156                         $schemas = [ $schema ];
1157                 }
1158                 $table = $this->realTableName( $table, 'raw' );
1159                 $etable = $this->addQuotes( $table );
1160                 foreach ( $schemas as $schema ) {
1161                         $eschema = $this->addQuotes( $schema );
1162                         $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1163                                 . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1164                                 . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1165                         $res = $this->query( $sql );
1166                         if ( $res && $res->numRows() ) {
1167                                 return true;
1168                         }
1169                 }
1170
1171                 return false;
1172         }
1173
1174         /**
1175          * For backward compatibility, this function checks both tables and views.
1176          * @param string $table
1177          * @param string $fname
1178          * @param bool|string $schema
1179          * @return bool
1180          */
1181         public function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1182                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1183         }
1184
1185         public function sequenceExists( $sequence, $schema = false ) {
1186                 return $this->relationExists( $sequence, 'S', $schema );
1187         }
1188
1189         public function triggerExists( $table, $trigger ) {
1190                 $q = <<<SQL
1191         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1192                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1193                         AND tgrelid=pg_class.oid
1194                         AND nspname=%s AND relname=%s AND tgname=%s
1195 SQL;
1196                 foreach ( $this->getCoreSchemas() as $schema ) {
1197                         $res = $this->query(
1198                                 sprintf(
1199                                         $q,
1200                                         $this->addQuotes( $schema ),
1201                                         $this->addQuotes( $table ),
1202                                         $this->addQuotes( $trigger )
1203                                 )
1204                         );
1205                         if ( $res && $res->numRows() ) {
1206                                 return true;
1207                         }
1208                 }
1209
1210                 return false;
1211         }
1212
1213         public function ruleExists( $table, $rule ) {
1214                 $exists = $this->selectField( 'pg_rules', 'rulename',
1215                         [
1216                                 'rulename' => $rule,
1217                                 'tablename' => $table,
1218                                 'schemaname' => $this->getCoreSchemas()
1219                         ]
1220                 );
1221
1222                 return $exists === $rule;
1223         }
1224
1225         public function constraintExists( $table, $constraint ) {
1226                 foreach ( $this->getCoreSchemas() as $schema ) {
1227                         $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1228                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1229                                 $this->addQuotes( $schema ),
1230                                 $this->addQuotes( $table ),
1231                                 $this->addQuotes( $constraint )
1232                         );
1233                         $res = $this->query( $sql );
1234                         if ( $res && $res->numRows() ) {
1235                                 return true;
1236                         }
1237                 }
1238                 return false;
1239         }
1240
1241         /**
1242          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1243          * @param string $schema
1244          * @return bool
1245          */
1246         public function schemaExists( $schema ) {
1247                 if ( !strlen( $schema ) ) {
1248                         return false; // short-circuit
1249                 }
1250
1251                 $res = $this->query(
1252                         "SELECT 1 FROM pg_catalog.pg_namespace " .
1253                         "WHERE nspname = " . $this->addQuotes( $schema ) . " LIMIT 1",
1254                         __METHOD__,
1255                         self::QUERY_IGNORE_DBO_TRX
1256                 );
1257
1258                 return ( $this->numRows( $res ) > 0 );
1259         }
1260
1261         /**
1262          * Returns true if a given role (i.e. user) exists, false otherwise.
1263          * @param string $roleName
1264          * @return bool
1265          */
1266         public function roleExists( $roleName ) {
1267                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1268                         [ 'rolname' => $roleName ], __METHOD__ );
1269
1270                 return (bool)$exists;
1271         }
1272
1273         /**
1274          * @param string $table
1275          * @param string $field
1276          * @return PostgresField|null
1277          */
1278         public function fieldInfo( $table, $field ) {
1279                 return PostgresField::fromText( $this, $table, $field );
1280         }
1281
1282         /**
1283          * pg_field_type() wrapper
1284          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1285          * @param int $index Field number, starting from 0
1286          * @return string
1287          */
1288         public function fieldType( $res, $index ) {
1289                 return pg_field_type( ResultWrapper::unwrap( $res ), $index );
1290         }
1291
1292         public function encodeBlob( $b ) {
1293                 return new PostgresBlob( pg_escape_bytea( $b ) );
1294         }
1295
1296         public function decodeBlob( $b ) {
1297                 if ( $b instanceof PostgresBlob ) {
1298                         $b = $b->fetch();
1299                 } elseif ( $b instanceof Blob ) {
1300                         return $b->fetch();
1301                 }
1302
1303                 return pg_unescape_bytea( $b );
1304         }
1305
1306         public function strencode( $s ) {
1307                 // Should not be called by us
1308                 return pg_escape_string( $this->getBindingHandle(), (string)$s );
1309         }
1310
1311         public function addQuotes( $s ) {
1312                 $conn = $this->getBindingHandle();
1313
1314                 if ( is_null( $s ) ) {
1315                         return 'NULL';
1316                 } elseif ( is_bool( $s ) ) {
1317                         return intval( $s );
1318                 } elseif ( $s instanceof Blob ) {
1319                         if ( $s instanceof PostgresBlob ) {
1320                                 $s = $s->fetch();
1321                         } else {
1322                                 $s = pg_escape_bytea( $conn, $s->fetch() );
1323                         }
1324                         return "'$s'";
1325                 } elseif ( $s instanceof NextSequenceValue ) {
1326                         return 'DEFAULT';
1327                 }
1328
1329                 return "'" . pg_escape_string( $conn, (string)$s ) . "'";
1330         }
1331
1332         public function makeSelectOptions( $options ) {
1333                 $preLimitTail = $postLimitTail = '';
1334                 $startOpts = $useIndex = $ignoreIndex = '';
1335
1336                 $noKeyOptions = [];
1337                 foreach ( $options as $key => $option ) {
1338                         if ( is_numeric( $key ) ) {
1339                                 $noKeyOptions[$option] = true;
1340                         }
1341                 }
1342
1343                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1344
1345                 $preLimitTail .= $this->makeOrderBy( $options );
1346
1347                 if ( isset( $options['FOR UPDATE'] ) ) {
1348                         $postLimitTail .= ' FOR UPDATE OF ' .
1349                                 implode( ', ', array_map( [ $this, 'tableName' ], $options['FOR UPDATE'] ) );
1350                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1351                         $postLimitTail .= ' FOR UPDATE';
1352                 }
1353
1354                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1355                         $startOpts .= 'DISTINCT';
1356                 }
1357
1358                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1359         }
1360
1361         public function buildConcat( $stringList ) {
1362                 return implode( ' || ', $stringList );
1363         }
1364
1365         public function buildGroupConcatField(
1366                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1367         ) {
1368                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1369
1370                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1371         }
1372
1373         public function buildStringCast( $field ) {
1374                 return $field . '::text';
1375         }
1376
1377         public function streamStatementEnd( &$sql, &$newLine ) {
1378                 # Allow dollar quoting for function declarations
1379                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1380                         if ( $this->delimiter ) {
1381                                 $this->delimiter = false;
1382                         } else {
1383                                 $this->delimiter = ';';
1384                         }
1385                 }
1386
1387                 return parent::streamStatementEnd( $sql, $newLine );
1388         }
1389
1390         public function doLockTables( array $read, array $write, $method ) {
1391                 $tablesWrite = [];
1392                 foreach ( $write as $table ) {
1393                         $tablesWrite[] = $this->tableName( $table );
1394                 }
1395                 $tablesRead = [];
1396                 foreach ( $read as $table ) {
1397                         $tablesRead[] = $this->tableName( $table );
1398                 }
1399
1400                 // Acquire locks for the duration of the current transaction...
1401                 if ( $tablesWrite ) {
1402                         $this->query(
1403                                 'LOCK TABLE ONLY ' . implode( ',', $tablesWrite ) . ' IN EXCLUSIVE MODE',
1404                                 $method
1405                         );
1406                 }
1407                 if ( $tablesRead ) {
1408                         $this->query(
1409                                 'LOCK TABLE ONLY ' . implode( ',', $tablesRead ) . ' IN SHARE MODE',
1410                                 $method
1411                         );
1412                 }
1413
1414                 return true;
1415         }
1416
1417         public function lockIsFree( $lockName, $method ) {
1418                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1419                         return false; // already held
1420                 }
1421                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1422                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1423                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1424                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1425                 $row = $this->fetchObject( $result );
1426
1427                 return ( $row->lockstatus === 't' );
1428         }
1429
1430         public function lock( $lockName, $method, $timeout = 5 ) {
1431                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1432                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1433                 $loop = new WaitConditionLoop(
1434                         function () use ( $lockName, $key, $timeout, $method ) {
1435                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1436                                 $row = $this->fetchObject( $res );
1437                                 if ( $row->lockstatus === 't' ) {
1438                                         parent::lock( $lockName, $method, $timeout ); // record
1439                                         return true;
1440                                 }
1441
1442                                 return WaitConditionLoop::CONDITION_CONTINUE;
1443                         },
1444                         $timeout
1445                 );
1446
1447                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1448         }
1449
1450         public function unlock( $lockName, $method ) {
1451                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1452                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1453                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1454                 $row = $this->fetchObject( $result );
1455
1456                 if ( $row->lockstatus === 't' ) {
1457                         parent::unlock( $lockName, $method ); // record
1458                         return true;
1459                 }
1460
1461                 $this->queryLogger->debug( __METHOD__ . " failed to release lock\n" );
1462
1463                 return false;
1464         }
1465
1466         public function serverIsReadOnly() {
1467                 $res = $this->query( "SHOW default_transaction_read_only", __METHOD__ );
1468                 $row = $this->fetchObject( $res );
1469
1470                 return $row ? ( strtolower( $row->default_transaction_read_only ) === 'on' ) : false;
1471         }
1472
1473         public static function getAttributes() {
1474                 return [ self::ATTR_SCHEMAS_AS_TABLE_GROUPS => true ];
1475         }
1476
1477         /**
1478          * @param string $lockName
1479          * @return string Integer
1480          */
1481         private function bigintFromLockName( $lockName ) {
1482                 return \Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1483         }
1484 }
1485
1486 /**
1487  * @deprecated since 1.29
1488  */
1489 class_alias( DatabasePostgres::class, 'DatabasePostgres' );