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;
  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->server = $server;
 101                 $this->user = $user;
 102                 $this->password = $password;
 103
 104                 $connectVars = [
 105                         // pg_connect() user $user as the default database. Since a database is *required*,
 106                         // at least pick a "don't care" database that is more likely to exist. This case
 107                         // arrises when LoadBalancer::getConnection( $i, [], '' ) is used.
 108                         'dbname' => strlen( $dbName ) ? $dbName : 'postgres',
 109                         'user' => $user,
 110                         'password' => $password
 111                 ];
 112                 if ( $server != false && $server != '' ) {
 113                         $connectVars['host'] = $server;
 114                 }
 115                 if ( (int)$this->port > 0 ) {
 116                         $connectVars['port'] = (int)$this->port;
 117                 }
 118                 if ( $this->flags & self::DBO_SSL ) {
 119                         $connectVars['sslmode'] = 1;
 120                 }
 121
 122                 $this->connectString = $this->makeConnectionString( $connectVars );
 123                 $this->close();
 124                 $this->installErrorHandler();
 125
 126                 try {
 127                         // Use new connections to let LoadBalancer/LBFactory handle reuse
 128                         $this->conn = pg_connect( $this->connectString, PGSQL_CONNECT_FORCE_NEW );
 129                 } catch ( Exception $ex ) {
 130                         $this->restoreErrorHandler();
 131                         throw $ex;
 132                 }
 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                 $this->opened = true;
 147
 148                 # If called from the command-line (e.g. importDump), only show errors
 149                 if ( $this->cliMode ) {
 150                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 151                 }
 152
 153                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 154                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 155                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 156                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 157                 $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 158
 159                 $this->determineCoreSchema( $schema );
 160                 $this->currentDomain = new DatabaseDomain( $dbName, $schema, $tablePrefix );
 161
 162                 return (bool)$this->conn;
 163         }
 164
 165         protected function relationSchemaQualifier() {
 166                 if ( $this->coreSchema === $this->currentDomain->getSchema() ) {
 167                         // The schema to be used is now in the search path; no need for explicit qualification
 168                         return '';
 169                 }
 170
 171                 return parent::relationSchemaQualifier();
 172         }
 173
 174         public function databasesAreIndependent() {
 175                 return true;
 176         }
 177
 178         public function doSelectDomain( DatabaseDomain $domain ) {
 179                 if ( $this->getDBname() !== $domain->getDatabase() ) {
 180                         // Postgres doesn't support selectDB in the same way MySQL does.
 181                         // So if the DB name doesn't match the open connection, open a new one
 182                         $this->open(
 183                                 $this->server,
 184                                 $this->user,
 185                                 $this->password,
 186                                 $domain->getDatabase(),
 187                                 $domain->getSchema(),
 188                                 $domain->getTablePrefix()
 189                         );
 190                 } else {
 191                         $this->currentDomain = $domain;
 192                 }
 193
 194                 return true;
 195         }
 196
 197         /**
 198          * @param string[] $vars
 199          * @return string
 200          */
 201         private function makeConnectionString( $vars ) {
 202                 $s = '';
 203                 foreach ( $vars as $name => $value ) {
 204                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 205                 }
 206
 207                 return $s;
 208         }
 209
 210         protected function closeConnection() {
 211                 return $this->conn ? pg_close( $this->conn ) : true;
 212         }
 213
 214         protected function isTransactableQuery( $sql ) {
 215                 return parent::isTransactableQuery( $sql ) &&
 216                         !preg_match( '/^SELECT\s+pg_(try_|)advisory_\w+\(/', $sql );
 217         }
 218
 219         public function doQuery( $sql ) {
 220                 $conn = $this->getBindingHandle();
 221
 222                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 223                 // Clear previously left over PQresult
 224                 while ( $res = pg_get_result( $conn ) ) {
 225                         pg_free_result( $res );
 226                 }
 227                 if ( pg_send_query( $conn, $sql ) === false ) {
 228                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 229                 }
 230                 $this->lastResultHandle = pg_get_result( $conn );
 231                 if ( pg_result_error( $this->lastResultHandle ) ) {
 232                         return false;
 233                 }
 234
 235                 return $this->lastResultHandle;
 236         }
 237
 238         protected function dumpError() {
 239                 $diags = [
 240                         PGSQL_DIAG_SEVERITY,
 241                         PGSQL_DIAG_SQLSTATE,
 242                         PGSQL_DIAG_MESSAGE_PRIMARY,
 243                         PGSQL_DIAG_MESSAGE_DETAIL,
 244                         PGSQL_DIAG_MESSAGE_HINT,
 245                         PGSQL_DIAG_STATEMENT_POSITION,
 246                         PGSQL_DIAG_INTERNAL_POSITION,
 247                         PGSQL_DIAG_INTERNAL_QUERY,
 248                         PGSQL_DIAG_CONTEXT,
 249                         PGSQL_DIAG_SOURCE_FILE,
 250                         PGSQL_DIAG_SOURCE_LINE,
 251                         PGSQL_DIAG_SOURCE_FUNCTION
 252                 ];
 253                 foreach ( $diags as $d ) {
 254                         $this->queryLogger->debug( sprintf( "PgSQL ERROR(%d): %s\n",
 255                                 $d, pg_result_error_field( $this->lastResultHandle, $d ) ) );
 256                 }
 257         }
 258
 259         public function freeResult( $res ) {
 260                 if ( $res instanceof ResultWrapper ) {
 261                         $res = $res->result;
 262                 }
 263                 Wikimedia\suppressWarnings();
 264                 $ok = pg_free_result( $res );
 265                 Wikimedia\restoreWarnings();
 266                 if ( !$ok ) {
 267                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 268                 }
 269         }
 270
 271         public function fetchObject( $res ) {
 272                 if ( $res instanceof ResultWrapper ) {
 273                         $res = $res->result;
 274                 }
 275                 Wikimedia\suppressWarnings();
 276                 $row = pg_fetch_object( $res );
 277                 Wikimedia\restoreWarnings();
 278                 # @todo FIXME: HACK HACK HACK HACK debug
 279
 280                 # @todo hashar: not sure if the following test really trigger if the object
 281                 #          fetching failed.
 282                 $conn = $this->getBindingHandle();
 283                 if ( pg_last_error( $conn ) ) {
 284                         throw new DBUnexpectedError(
 285                                 $this,
 286                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 287                         );
 288                 }
 289
 290                 return $row;
 291         }
 292
 293         public function fetchRow( $res ) {
 294                 if ( $res instanceof ResultWrapper ) {
 295                         $res = $res->result;
 296                 }
 297                 Wikimedia\suppressWarnings();
 298                 $row = pg_fetch_array( $res );
 299                 Wikimedia\restoreWarnings();
 300
 301                 $conn = $this->getBindingHandle();
 302                 if ( pg_last_error( $conn ) ) {
 303                         throw new DBUnexpectedError(
 304                                 $this,
 305                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 306                         );
 307                 }
 308
 309                 return $row;
 310         }
 311
 312         public function numRows( $res ) {
 313                 if ( $res === false ) {
 314                         return 0;
 315                 }
 316
 317                 if ( $res instanceof ResultWrapper ) {
 318                         $res = $res->result;
 319                 }
 320                 Wikimedia\suppressWarnings();
 321                 $n = pg_num_rows( $res );
 322                 Wikimedia\restoreWarnings();
 323
 324                 $conn = $this->getBindingHandle();
 325                 if ( pg_last_error( $conn ) ) {
 326                         throw new DBUnexpectedError(
 327                                 $this,
 328                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 329                         );
 330                 }
 331
 332                 return $n;
 333         }
 334
 335         public function numFields( $res ) {
 336                 if ( $res instanceof ResultWrapper ) {
 337                         $res = $res->result;
 338                 }
 339
 340                 return pg_num_fields( $res );
 341         }
 342
 343         public function fieldName( $res, $n ) {
 344                 if ( $res instanceof ResultWrapper ) {
 345                         $res = $res->result;
 346                 }
 347
 348                 return pg_field_name( $res, $n );
 349         }
 350
 351         public function insertId() {
 352                 $res = $this->query( "SELECT lastval()" );
 353                 $row = $this->fetchRow( $res );
 354                 return is_null( $row[0] ) ? null : (int)$row[0];
 355         }
 356
 357         public function dataSeek( $res, $row ) {
 358                 if ( $res instanceof ResultWrapper ) {
 359                         $res = $res->result;
 360                 }
 361
 362                 return pg_result_seek( $res, $row );
 363         }
 364
 365         public function lastError() {
 366                 if ( $this->conn ) {
 367                         if ( $this->lastResultHandle ) {
 368                                 return pg_result_error( $this->lastResultHandle );
 369                         } else {
 370                                 return pg_last_error();
 371                         }
 372                 }
 373
 374                 return $this->getLastPHPError() ?: 'No database connection';
 375         }
 376
 377         public function lastErrno() {
 378                 if ( $this->lastResultHandle ) {
 379                         return pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
 380                 } else {
 381                         return false;
 382                 }
 383         }
 384
 385         protected function fetchAffectedRowCount() {
 386                 if ( !$this->lastResultHandle ) {
 387                         return 0;
 388                 }
 389
 390                 return pg_affected_rows( $this->lastResultHandle );
 391         }
 392
 393         /**
 394          * Estimate rows in dataset
 395          * Returns estimated count, based on EXPLAIN output
 396          * This is not necessarily an accurate estimate, so use sparingly
 397          * Returns -1 if count cannot be found
 398          * Takes same arguments as Database::select()
 399          *
 400          * @param string $table
 401          * @param string $var
 402          * @param string $conds
 403          * @param string $fname
 404          * @param array $options
 405          * @param array $join_conds
 406          * @return int
 407          */
 408         public function estimateRowCount( $table, $var = '*', $conds = '',
 409                 $fname = __METHOD__, $options = [], $join_conds = []
 410         ) {
 411                 $conds = $this->normalizeConditions( $conds, $fname );
 412                 $column = $this->extractSingleFieldFromList( $var );
 413                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 414                         $conds[] = "$column IS NOT NULL";
 415                 }
 416
 417                 $options['EXPLAIN'] = true;
 418                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 419                 $rows = -1;
 420                 if ( $res ) {
 421                         $row = $this->fetchRow( $res );
 422                         $count = [];
 423                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 424                                 $rows = (int)$count[1];
 425                         }
 426                 }
 427
 428                 return $rows;
 429         }
 430
 431         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 432                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 433                 $res = $this->query( $sql, $fname );
 434                 if ( !$res ) {
 435                         return null;
 436                 }
 437                 foreach ( $res as $row ) {
 438                         if ( $row->indexname == $this->indexName( $index ) ) {
 439                                 return $row;
 440                         }
 441                 }
 442
 443                 return false;
 444         }
 445
 446         public function indexAttributes( $index, $schema = false ) {
 447                 if ( $schema === false ) {
 448                         $schemas = $this->getCoreSchemas();
 449                 } else {
 450                         $schemas = [ $schema ];
 451                 }
 452
 453                 $eindex = $this->addQuotes( $index );
 454
 455                 foreach ( $schemas as $schema ) {
 456                         $eschema = $this->addQuotes( $schema );
 457                         /*
 458                          * A subquery would be not needed if we didn't care about the order
 459                          * of attributes, but we do
 460                          */
 461                         $sql = <<<__INDEXATTR__
 462
 463                                 SELECT opcname,
 464                                         attname,
 465                                         i.indoption[s.g] as option,
 466                                         pg_am.amname
 467                                 FROM
 468                                         (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 469                                                 FROM
 470                                                         pg_index isub
 471                                                 JOIN pg_class cis
 472                                                         ON cis.oid=isub.indexrelid
 473                                                 JOIN pg_namespace ns
 474                                                         ON cis.relnamespace = ns.oid
 475                                                 WHERE cis.relname=$eindex AND ns.nspname=$eschema) AS s,
 476                                         pg_attribute,
 477                                         pg_opclass opcls,
 478                                         pg_am,
 479                                         pg_class ci
 480                                         JOIN pg_index i
 481                                                 ON ci.oid=i.indexrelid
 482                                         JOIN pg_class ct
 483                                                 ON ct.oid = i.indrelid
 484                                         JOIN pg_namespace n
 485                                                 ON ci.relnamespace = n.oid
 486                                         WHERE
 487                                                 ci.relname=$eindex AND n.nspname=$eschema
 488                                                 AND     attrelid = ct.oid
 489                                                 AND     i.indkey[s.g] = attnum
 490                                                 AND     i.indclass[s.g] = opcls.oid
 491                                                 AND     pg_am.oid = opcls.opcmethod
 492 __INDEXATTR__;
 493                         $res = $this->query( $sql, __METHOD__ );
 494                         $a = [];
 495                         if ( $res ) {
 496                                 foreach ( $res as $row ) {
 497                                         $a[] = [
 498                                                 $row->attname,
 499                                                 $row->opcname,
 500                                                 $row->amname,
 501                                                 $row->option ];
 502                                 }
 503                                 return $a;
 504                         }
 505                 }
 506                 return null;
 507         }
 508
 509         public function indexUnique( $table, $index, $fname = __METHOD__ ) {
 510                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 511                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 512                         $this->strencode( $this->indexName( $index ) ) .
 513                         ")'";
 514                 $res = $this->query( $sql, $fname );
 515                 if ( !$res ) {
 516                         return null;
 517                 }
 518
 519                 return $res->numRows() > 0;
 520         }
 521
 522         public function selectSQLText(
 523                 $table, $vars, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
 524         ) {
 525                 if ( is_string( $options ) ) {
 526                         $options = [ $options ];
 527                 }
 528
 529                 // Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 530                 // to the parent function to get the actual SQL text.
 531                 // In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 532                 // can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to
 533                 // do so causes a DB error. This wrapper checks which tables can be locked and adjusts it
 534                 // accordingly.
 535                 // MySQL uses "ORDER BY NULL" as an optimization hint, but that is illegal in PostgreSQL.
 536                 if ( is_array( $options ) ) {
 537                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 538                         if ( $forUpdateKey !== false && $join_conds ) {
 539                                 unset( $options[$forUpdateKey] );
 540                                 $options['FOR UPDATE'] = [];
 541
 542                                 $toCheck = $table;
 543                                 reset( $toCheck );
 544                                 while ( $toCheck ) {
 545                                         $alias = key( $toCheck );
 546                                         $name = $toCheck[$alias];
 547                                         unset( $toCheck[$alias] );
 548
 549                                         $hasAlias = !is_numeric( $alias );
 550                                         if ( !$hasAlias && is_string( $name ) ) {
 551                                                 $alias = $name;
 552                                         }
 553
 554                                         if ( !isset( $join_conds[$alias] ) ||
 555                                                 !preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_conds[$alias][0] )
 556                                         ) {
 557                                                 if ( is_array( $name ) ) {
 558                                                         // It's a parenthesized group, process all the tables inside the group.
 559                                                         $toCheck = array_merge( $toCheck, $name );
 560                                                 } else {
 561                                                         // Quote alias names so $this->tableName() won't mangle them
 562                                                         $options['FOR UPDATE'][] = $hasAlias ? $this->addIdentifierQuotes( $alias ) : $alias;
 563                                                 }
 564                                         }
 565                                 }
 566                         }
 567
 568                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 569                                 unset( $options['ORDER BY'] );
 570                         }
 571                 }
 572
 573                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 574         }
 575
 576         /** @inheritDoc */
 577         public function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 578                 if ( !count( $args ) ) {
 579                         return true;
 580                 }
 581
 582                 $table = $this->tableName( $table );
 583                 if ( !isset( $this->numericVersion ) ) {
 584                         $this->getServerVersion();
 585                 }
 586
 587                 if ( !is_array( $options ) ) {
 588                         $options = [ $options ];
 589                 }
 590
 591                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 592                         $rows = $args;
 593                         $keys = array_keys( $args[0] );
 594                 } else {
 595                         $rows = [ $args ];
 596                         $keys = array_keys( $args );
 597                 }
 598
 599                 $ignore = in_array( 'IGNORE', $options );
 600
 601                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 602
 603                 if ( $this->numericVersion >= 9.5 || !$ignore ) {
 604                         // No IGNORE or our PG has "ON CONFLICT DO NOTHING"
 605                         $first = true;
 606                         foreach ( $rows as $row ) {
 607                                 if ( $first ) {
 608                                         $first = false;
 609                                 } else {
 610                                         $sql .= ',';
 611                                 }
 612                                 $sql .= '(' . $this->makeList( $row ) . ')';
 613                         }
 614                         if ( $ignore ) {
 615                                 $sql .= ' ON CONFLICT DO NOTHING';
 616                         }
 617                         $this->query( $sql, $fname );
 618                 } else {
 619                         // Emulate IGNORE by doing each row individually, with savepoints
 620                         // to roll back as necessary.
 621                         $numrowsinserted = 0;
 622
 623                         $tok = $this->startAtomic( "$fname (outer)", self::ATOMIC_CANCELABLE );
 624                         try {
 625                                 foreach ( $rows as $row ) {
 626                                         $tempsql = $sql;
 627                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 628
 629                                         $this->startAtomic( "$fname (inner)", self::ATOMIC_CANCELABLE );
 630                                         try {
 631                                                 $this->query( $tempsql, $fname );
 632                                                 $this->endAtomic( "$fname (inner)" );
 633                                                 $numrowsinserted++;
 634                                         } catch ( DBQueryError $e ) {
 635                                                 $this->cancelAtomic( "$fname (inner)" );
 636                                                 // Our IGNORE is supposed to ignore duplicate key errors, but not others.
 637                                                 // (even though MySQL's version apparently ignores all errors)
 638                                                 if ( $e->errno !== '23505' ) {
 639                                                         throw $e;
 640                                                 }
 641                                         }
 642                                 }
 643                         } catch ( Exception $e ) {
 644                                 $this->cancelAtomic( "$fname (outer)", $tok );
 645                                 throw $e;
 646                         }
 647                         $this->endAtomic( "$fname (outer)" );
 648
 649                         // Set the affected row count for the whole operation
 650                         $this->affectedRowCount = $numrowsinserted;
 651                 }
 652
 653                 return true;
 654         }
 655
 656         protected function makeUpdateOptionsArray( $options ) {
 657                 if ( !is_array( $options ) ) {
 658                         $options = [ $options ];
 659                 }
 660
 661                 // PostgreSQL doesn't support anything like "ignore" for
 662                 // UPDATE.
 663                 $options = array_diff( $options, [ 'IGNORE' ] );
 664
 665                 return parent::makeUpdateOptionsArray( $options );
 666         }
 667
 668         /**
 669          * INSERT SELECT wrapper
 670          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 671          * Source items may be literals rather then field names, but strings should
 672          * be quoted with Database::addQuotes()
 673          * $conds may be "*" to copy the whole table
 674          * srcTable may be an array of tables.
 675          * @todo FIXME: Implement this a little better (separate select/insert)?
 676          *
 677          * @param string $destTable
 678          * @param array|string $srcTable
 679          * @param array $varMap
 680          * @param array $conds
 681          * @param string $fname
 682          * @param array $insertOptions
 683          * @param array $selectOptions
 684          * @param array $selectJoinConds
 685          */
 686         protected function nativeInsertSelect(
 687                 $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 688                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 689         ) {
 690                 if ( !is_array( $insertOptions ) ) {
 691                         $insertOptions = [ $insertOptions ];
 692                 }
 693
 694                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 695                         if ( $this->getServerVersion() >= 9.5 ) {
 696                                 // Use ON CONFLICT DO NOTHING if we have it for IGNORE
 697                                 $destTable = $this->tableName( $destTable );
 698
 699                                 $selectSql = $this->selectSQLText(
 700                                         $srcTable,
 701                                         array_values( $varMap ),
 702                                         $conds,
 703                                         $fname,
 704                                         $selectOptions,
 705                                         $selectJoinConds
 706                                 );
 707
 708                                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ') ' .
 709                                         $selectSql . ' ON CONFLICT DO NOTHING';
 710
 711                                 $this->query( $sql, $fname );
 712                         } else {
 713                                 // IGNORE and we don't have ON CONFLICT DO NOTHING, so just use the non-native version
 714                                 $this->nonNativeInsertSelect(
 715                                         $destTable, $srcTable, $varMap, $conds, $fname,
 716                                         $insertOptions, $selectOptions, $selectJoinConds
 717                                 );
 718                         }
 719                 } else {
 720                         parent::nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname,
 721                                 $insertOptions, $selectOptions, $selectJoinConds );
 722                 }
 723         }
 724
 725         public function tableName( $name, $format = 'quoted' ) {
 726                 // Replace reserved words with better ones
 727                 $name = $this->remappedTableName( $name );
 728
 729                 return parent::tableName( $name, $format );
 730         }
 731
 732         /**
 733          * @param string $name
 734          * @return string Value of $name or remapped name if $name is a reserved keyword
 735          */
 736         public function remappedTableName( $name ) {
 737                 return $this->keywordTableMap[$name] ?? $name;
 738         }
 739
 740         /**
 741          * @param string $name
 742          * @param string $format
 743          * @return string Qualified and encoded (if requested) table name
 744          */
 745         public function realTableName( $name, $format = 'quoted' ) {
 746                 return parent::tableName( $name, $format );
 747         }
 748
 749         public function nextSequenceValue( $seqName ) {
 750                 return new NextSequenceValue;
 751         }
 752
 753         /**
 754          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 755          *
 756          * @param string $seqName
 757          * @return int
 758          */
 759         public function currentSequenceValue( $seqName ) {
 760                 $safeseq = str_replace( "'", "''", $seqName );
 761                 $res = $this->query( "SELECT currval('$safeseq')" );
 762                 $row = $this->fetchRow( $res );
 763                 $currval = $row[0];
 764
 765                 return $currval;
 766         }
 767
 768         public function textFieldSize( $table, $field ) {
 769                 $table = $this->tableName( $table );
 770                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 771                         FROM pg_class c, pg_attribute a, pg_type t
 772                         WHERE relname='$table' AND a.attrelid=c.oid AND
 773                                 a.atttypid=t.oid and a.attname='$field'";
 774                 $res = $this->query( $sql );
 775                 $row = $this->fetchObject( $res );
 776                 if ( $row->ftype == 'varchar' ) {
 777                         $size = $row->size - 4;
 778                 } else {
 779                         $size = $row->size;
 780                 }
 781
 782                 return $size;
 783         }
 784
 785         public function limitResult( $sql, $limit, $offset = false ) {
 786                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 787         }
 788
 789         public function wasDeadlock() {
 790                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 791                 return $this->lastErrno() === '40P01';
 792         }
 793
 794         public function wasLockTimeout() {
 795                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 796                 return $this->lastErrno() === '55P03';
 797         }
 798
 799         public function wasConnectionError( $errno ) {
 800                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 801                 static $codes = [ '08000', '08003', '08006', '08001', '08004', '57P01', '57P03', '53300' ];
 802
 803                 return in_array( $errno, $codes, true );
 804         }
 805
 806         protected function wasKnownStatementRollbackError() {
 807                 return false; // transaction has to be rolled-back from error state
 808         }
 809
 810         public function duplicateTableStructure(
 811                 $oldName, $newName, $temporary = false, $fname = __METHOD__
 812         ) {
 813                 $newNameE = $this->addIdentifierQuotes( $newName );
 814                 $oldNameE = $this->addIdentifierQuotes( $oldName );
 815
 816                 $temporary = $temporary ? 'TEMPORARY' : '';
 817
 818                 $ret = $this->query( "CREATE $temporary TABLE $newNameE " .
 819                         "(LIKE $oldNameE INCLUDING DEFAULTS INCLUDING INDEXES)", $fname );
 820                 if ( !$ret ) {
 821                         return $ret;
 822                 }
 823
 824                 $res = $this->query( 'SELECT attname FROM pg_class c'
 825                         . ' JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 826                         . ' JOIN pg_attribute a ON (a.attrelid = c.oid)'
 827                         . ' JOIN pg_attrdef d ON (c.oid=d.adrelid and a.attnum=d.adnum)'
 828                         . ' WHERE relkind = \'r\''
 829                         . ' AND nspname = ' . $this->addQuotes( $this->getCoreSchema() )
 830                         . ' AND relname = ' . $this->addQuotes( $oldName )
 831                         . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 832                         $fname
 833                 );
 834                 $row = $this->fetchObject( $res );
 835                 if ( $row ) {
 836                         $field = $row->attname;
 837                         $newSeq = "{$newName}_{$field}_seq";
 838                         $fieldE = $this->addIdentifierQuotes( $field );
 839                         $newSeqE = $this->addIdentifierQuotes( $newSeq );
 840                         $newSeqQ = $this->addQuotes( $newSeq );
 841                         $this->query( "CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE", $fname );
 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          * @suppress SecurityCheck-SQLInjection array_map not recognized T204911
 888          */
 889         public function listTables( $prefix = null, $fname = __METHOD__ ) {
 890                 $eschemas = implode( ',', array_map( [ $this, 'addQuotes' ], $this->getCoreSchemas() ) );
 891                 $result = $this->query(
 892                         "SELECT DISTINCT tablename FROM pg_tables WHERE schemaname IN ($eschemas)", $fname );
 893                 $endArray = [];
 894
 895                 foreach ( $result as $table ) {
 896                         $vars = get_object_vars( $table );
 897                         $table = array_pop( $vars );
 898                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
 899                                 $endArray[] = $table;
 900                         }
 901                 }
 902
 903                 return $endArray;
 904         }
 905
 906         public function timestamp( $ts = 0 ) {
 907                 $ct = new ConvertibleTimestamp( $ts );
 908
 909                 return $ct->getTimestamp( TS_POSTGRES );
 910         }
 911
 912         /**
 913          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
 914          * to https://secure.php.net/manual/en/ref.pgsql.php
 915          *
 916          * Parsing a postgres array can be a tricky problem, he's my
 917          * take on this, it handles multi-dimensional arrays plus
 918          * escaping using a nasty regexp to determine the limits of each
 919          * data-item.
 920          *
 921          * This should really be handled by PHP PostgreSQL module
 922          *
 923          * @since 1.19
 924          * @param string $text Postgreql array returned in a text form like {a,b}
 925          * @param string[] $output
 926          * @param int|bool $limit
 927          * @param int $offset
 928          * @return string[]
 929          */
 930         private function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
 931                 if ( $limit === false ) {
 932                         $limit = strlen( $text ) - 1;
 933                         $output = [];
 934                 }
 935                 if ( $text == '{}' ) {
 936                         return $output;
 937                 }
 938                 do {
 939                         if ( $text[$offset] != '{' ) {
 940                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
 941                                         $text, $match, 0, $offset );
 942                                 $offset += strlen( $match[0] );
 943                                 $output[] = ( $match[1][0] != '"'
 944                                         ? $match[1]
 945                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
 946                                 if ( $match[3] == '},' ) {
 947                                         return $output;
 948                                 }
 949                         } else {
 950                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
 951                         }
 952                 } while ( $limit > $offset );
 953
 954                 return $output;
 955         }
 956
 957         public function aggregateValue( $valuedata, $valuename = 'value' ) {
 958                 return $valuedata;
 959         }
 960
 961         public function getSoftwareLink() {
 962                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
 963         }
 964
 965         /**
 966          * Return current schema (executes SELECT current_schema())
 967          * Needs transaction
 968          *
 969          * @since 1.19
 970          * @return string Default schema for the current session
 971          */
 972         public function getCurrentSchema() {
 973                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
 974                 $row = $this->fetchRow( $res );
 975
 976                 return $row[0];
 977         }
 978
 979         /**
 980          * Return list of schemas which are accessible without schema name
 981          * This is list does not contain magic keywords like "$user"
 982          * Needs transaction
 983          *
 984          * @see getSearchPath()
 985          * @see setSearchPath()
 986          * @since 1.19
 987          * @return array List of actual schemas for the current sesson
 988          */
 989         public function getSchemas() {
 990                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
 991                 $row = $this->fetchRow( $res );
 992                 $schemas = [];
 993
 994                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
 995
 996                 return $this->pg_array_parse( $row[0], $schemas );
 997         }
 998
 999         /**
1000          * Return search patch for schemas
1001          * This is different from getSchemas() since it contain magic keywords
1002          * (like "$user").
1003          * Needs transaction
1004          *
1005          * @since 1.19
1006          * @return array How to search for table names schemas for the current user
1007          */
1008         public function getSearchPath() {
1009                 $res = $this->query( "SHOW search_path", __METHOD__ );
1010                 $row = $this->fetchRow( $res );
1011
1012                 /* PostgreSQL returns SHOW values as strings */
1013
1014                 return explode( ",", $row[0] );
1015         }
1016
1017         /**
1018          * Update search_path, values should already be sanitized
1019          * Values may contain magic keywords like "$user"
1020          * @since 1.19
1021          *
1022          * @param array $search_path List of schemas to be searched by default
1023          */
1024         private function setSearchPath( $search_path ) {
1025                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1026         }
1027
1028         /**
1029          * Determine default schema for the current application
1030          * Adjust this session schema search path if desired schema exists
1031          * and is not alread there.
1032          *
1033          * We need to have name of the core schema stored to be able
1034          * to query database metadata.
1035          *
1036          * This will be also called by the installer after the schema is created
1037          *
1038          * @since 1.19
1039          *
1040          * @param string $desiredSchema
1041          */
1042         public function determineCoreSchema( $desiredSchema ) {
1043                 $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
1044                 if ( $this->schemaExists( $desiredSchema ) ) {
1045                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1046                                 $this->coreSchema = $desiredSchema;
1047                                 $this->queryLogger->debug(
1048                                         "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1049                         } else {
1050                                 /**
1051                                  * Prepend our schema (e.g. 'mediawiki') in front
1052                                  * of the search path
1053                                  * Fixes T17816
1054                                  */
1055                                 $search_path = $this->getSearchPath();
1056                                 array_unshift( $search_path,
1057                                         $this->addIdentifierQuotes( $desiredSchema ) );
1058                                 $this->setSearchPath( $search_path );
1059                                 $this->coreSchema = $desiredSchema;
1060                                 $this->queryLogger->debug(
1061                                         "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1062                         }
1063                 } else {
1064                         $this->coreSchema = $this->getCurrentSchema();
1065                         $this->queryLogger->debug(
1066                                 "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1067                                 $this->coreSchema . "\"\n" );
1068                 }
1069                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1070                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
1071         }
1072
1073         /**
1074          * Return schema name for core application tables
1075          *
1076          * @since 1.19
1077          * @return string Core schema name
1078          */
1079         public function getCoreSchema() {
1080                 return $this->coreSchema;
1081         }
1082
1083         /**
1084          * Return schema names for temporary tables and core application tables
1085          *
1086          * @since 1.31
1087          * @return string[] schema names
1088          */
1089         public function getCoreSchemas() {
1090                 if ( $this->tempSchema ) {
1091                         return [ $this->tempSchema, $this->getCoreSchema() ];
1092                 }
1093
1094                 $res = $this->query(
1095                         "SELECT nspname FROM pg_catalog.pg_namespace n WHERE n.oid = pg_my_temp_schema()", __METHOD__
1096                 );
1097                 $row = $this->fetchObject( $res );
1098                 if ( $row ) {
1099                         $this->tempSchema = $row->nspname;
1100                         return [ $this->tempSchema, $this->getCoreSchema() ];
1101                 }
1102
1103                 return [ $this->getCoreSchema() ];
1104         }
1105
1106         public function getServerVersion() {
1107                 if ( !isset( $this->numericVersion ) ) {
1108                         $conn = $this->getBindingHandle();
1109                         $versionInfo = pg_version( $conn );
1110                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1111                                 // Old client, abort install
1112                                 $this->numericVersion = '7.3 or earlier';
1113                         } elseif ( isset( $versionInfo['server'] ) ) {
1114                                 // Normal client
1115                                 $this->numericVersion = $versionInfo['server'];
1116                         } else {
1117                                 // T18937: broken pgsql extension from PHP<5.3
1118                                 $this->numericVersion = pg_parameter_status( $conn, 'server_version' );
1119                         }
1120                 }
1121
1122                 return $this->numericVersion;
1123         }
1124
1125         /**
1126          * Query whether a given relation exists (in the given schema, or the
1127          * default mw one if not given)
1128          * @param string $table
1129          * @param array|string $types
1130          * @param bool|string $schema
1131          * @return bool
1132          */
1133         private function relationExists( $table, $types, $schema = false ) {
1134                 if ( !is_array( $types ) ) {
1135                         $types = [ $types ];
1136                 }
1137                 if ( $schema === false ) {
1138                         $schemas = $this->getCoreSchemas();
1139                 } else {
1140                         $schemas = [ $schema ];
1141                 }
1142                 $table = $this->realTableName( $table, 'raw' );
1143                 $etable = $this->addQuotes( $table );
1144                 foreach ( $schemas as $schema ) {
1145                         $eschema = $this->addQuotes( $schema );
1146                         $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1147                                 . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1148                                 . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1149                         $res = $this->query( $sql );
1150                         if ( $res && $res->numRows() ) {
1151                                 return true;
1152                         }
1153                 }
1154
1155                 return false;
1156         }
1157
1158         /**
1159          * For backward compatibility, this function checks both tables and views.
1160          * @param string $table
1161          * @param string $fname
1162          * @param bool|string $schema
1163          * @return bool
1164          */
1165         public function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1166                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1167         }
1168
1169         public function sequenceExists( $sequence, $schema = false ) {
1170                 return $this->relationExists( $sequence, 'S', $schema );
1171         }
1172
1173         public function triggerExists( $table, $trigger ) {
1174                 $q = <<<SQL
1175         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1176                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1177                         AND tgrelid=pg_class.oid
1178                         AND nspname=%s AND relname=%s AND tgname=%s
1179 SQL;
1180                 foreach ( $this->getCoreSchemas() as $schema ) {
1181                         $res = $this->query(
1182                                 sprintf(
1183                                         $q,
1184                                         $this->addQuotes( $schema ),
1185                                         $this->addQuotes( $table ),
1186                                         $this->addQuotes( $trigger )
1187                                 )
1188                         );
1189                         if ( $res && $res->numRows() ) {
1190                                 return true;
1191                         }
1192                 }
1193
1194                 return false;
1195         }
1196
1197         public function ruleExists( $table, $rule ) {
1198                 $exists = $this->selectField( 'pg_rules', 'rulename',
1199                         [
1200                                 'rulename' => $rule,
1201                                 'tablename' => $table,
1202                                 'schemaname' => $this->getCoreSchemas()
1203                         ]
1204                 );
1205
1206                 return $exists === $rule;
1207         }
1208
1209         public function constraintExists( $table, $constraint ) {
1210                 foreach ( $this->getCoreSchemas() as $schema ) {
1211                         $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1212                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1213                                 $this->addQuotes( $schema ),
1214                                 $this->addQuotes( $table ),
1215                                 $this->addQuotes( $constraint )
1216                         );
1217                         $res = $this->query( $sql );
1218                         if ( $res && $res->numRows() ) {
1219                                 return true;
1220                         }
1221                 }
1222                 return false;
1223         }
1224
1225         /**
1226          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1227          * @param string $schema
1228          * @return bool
1229          */
1230         public function schemaExists( $schema ) {
1231                 if ( !strlen( $schema ) ) {
1232                         return false; // short-circuit
1233                 }
1234
1235                 $exists = $this->selectField(
1236                         '"pg_catalog"."pg_namespace"', 1, [ 'nspname' => $schema ], __METHOD__ );
1237
1238                 return (bool)$exists;
1239         }
1240
1241         /**
1242          * Returns true if a given role (i.e. user) exists, false otherwise.
1243          * @param string $roleName
1244          * @return bool
1245          */
1246         public function roleExists( $roleName ) {
1247                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1248                         [ 'rolname' => $roleName ], __METHOD__ );
1249
1250                 return (bool)$exists;
1251         }
1252
1253         /**
1254          * @param string $table
1255          * @param string $field
1256          * @return PostgresField|null
1257          */
1258         public function fieldInfo( $table, $field ) {
1259                 return PostgresField::fromText( $this, $table, $field );
1260         }
1261
1262         /**
1263          * pg_field_type() wrapper
1264          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1265          * @param int $index Field number, starting from 0
1266          * @return string
1267          */
1268         public function fieldType( $res, $index ) {
1269                 if ( $res instanceof ResultWrapper ) {
1270                         $res = $res->result;
1271                 }
1272
1273                 return pg_field_type( $res, $index );
1274         }
1275
1276         public function encodeBlob( $b ) {
1277                 return new PostgresBlob( pg_escape_bytea( $b ) );
1278         }
1279
1280         public function decodeBlob( $b ) {
1281                 if ( $b instanceof PostgresBlob ) {
1282                         $b = $b->fetch();
1283                 } elseif ( $b instanceof Blob ) {
1284                         return $b->fetch();
1285                 }
1286
1287                 return pg_unescape_bytea( $b );
1288         }
1289
1290         public function strencode( $s ) {
1291                 // Should not be called by us
1292                 return pg_escape_string( $this->getBindingHandle(), (string)$s );
1293         }
1294
1295         public function addQuotes( $s ) {
1296                 $conn = $this->getBindingHandle();
1297
1298                 if ( is_null( $s ) ) {
1299                         return 'NULL';
1300                 } elseif ( is_bool( $s ) ) {
1301                         return intval( $s );
1302                 } elseif ( $s instanceof Blob ) {
1303                         if ( $s instanceof PostgresBlob ) {
1304                                 $s = $s->fetch();
1305                         } else {
1306                                 $s = pg_escape_bytea( $conn, $s->fetch() );
1307                         }
1308                         return "'$s'";
1309                 } elseif ( $s instanceof NextSequenceValue ) {
1310                         return 'DEFAULT';
1311                 }
1312
1313                 return "'" . pg_escape_string( $conn, (string)$s ) . "'";
1314         }
1315
1316         public function makeSelectOptions( $options ) {
1317                 $preLimitTail = $postLimitTail = '';
1318                 $startOpts = $useIndex = $ignoreIndex = '';
1319
1320                 $noKeyOptions = [];
1321                 foreach ( $options as $key => $option ) {
1322                         if ( is_numeric( $key ) ) {
1323                                 $noKeyOptions[$option] = true;
1324                         }
1325                 }
1326
1327                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1328
1329                 $preLimitTail .= $this->makeOrderBy( $options );
1330
1331                 if ( isset( $options['FOR UPDATE'] ) ) {
1332                         $postLimitTail .= ' FOR UPDATE OF ' .
1333                                 implode( ', ', array_map( [ $this, 'tableName' ], $options['FOR UPDATE'] ) );
1334                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1335                         $postLimitTail .= ' FOR UPDATE';
1336                 }
1337
1338                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1339                         $startOpts .= 'DISTINCT';
1340                 }
1341
1342                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1343         }
1344
1345         public function getServer() {
1346                 return $this->server;
1347         }
1348
1349         public function buildConcat( $stringList ) {
1350                 return implode( ' || ', $stringList );
1351         }
1352
1353         public function buildGroupConcatField(
1354                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1355         ) {
1356                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1357
1358                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1359         }
1360
1361         public function buildStringCast( $field ) {
1362                 return $field . '::text';
1363         }
1364
1365         public function streamStatementEnd( &$sql, &$newLine ) {
1366                 # Allow dollar quoting for function declarations
1367                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1368                         if ( $this->delimiter ) {
1369                                 $this->delimiter = false;
1370                         } else {
1371                                 $this->delimiter = ';';
1372                         }
1373                 }
1374
1375                 return parent::streamStatementEnd( $sql, $newLine );
1376         }
1377
1378         public function doLockTables( array $read, array $write, $method ) {
1379                 $tablesWrite = [];
1380                 foreach ( $write as $table ) {
1381                         $tablesWrite[] = $this->tableName( $table );
1382                 }
1383                 $tablesRead = [];
1384                 foreach ( $read as $table ) {
1385                         $tablesRead[] = $this->tableName( $table );
1386                 }
1387
1388                 // Acquire locks for the duration of the current transaction...
1389                 if ( $tablesWrite ) {
1390                         $this->query(
1391                                 'LOCK TABLE ONLY ' . implode( ',', $tablesWrite ) . ' IN EXCLUSIVE MODE',
1392                                 $method
1393                         );
1394                 }
1395                 if ( $tablesRead ) {
1396                         $this->query(
1397                                 'LOCK TABLE ONLY ' . implode( ',', $tablesRead ) . ' IN SHARE MODE',
1398                                 $method
1399                         );
1400                 }
1401
1402                 return true;
1403         }
1404
1405         public function lockIsFree( $lockName, $method ) {
1406                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1407                         return false; // already held
1408                 }
1409                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1410                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1411                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1412                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1413                 $row = $this->fetchObject( $result );
1414
1415                 return ( $row->lockstatus === 't' );
1416         }
1417
1418         public function lock( $lockName, $method, $timeout = 5 ) {
1419                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1420                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1421                 $loop = new WaitConditionLoop(
1422                         function () use ( $lockName, $key, $timeout, $method ) {
1423                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1424                                 $row = $this->fetchObject( $res );
1425                                 if ( $row->lockstatus === 't' ) {
1426                                         parent::lock( $lockName, $method, $timeout ); // record
1427                                         return true;
1428                                 }
1429
1430                                 return WaitConditionLoop::CONDITION_CONTINUE;
1431                         },
1432                         $timeout
1433                 );
1434
1435                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1436         }
1437
1438         public function unlock( $lockName, $method ) {
1439                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1440                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1441                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1442                 $row = $this->fetchObject( $result );
1443
1444                 if ( $row->lockstatus === 't' ) {
1445                         parent::unlock( $lockName, $method ); // record
1446                         return true;
1447                 }
1448
1449                 $this->queryLogger->debug( __METHOD__ . " failed to release lock\n" );
1450
1451                 return false;
1452         }
1453
1454         public function serverIsReadOnly() {
1455                 $res = $this->query( "SHOW default_transaction_read_only", __METHOD__ );
1456                 $row = $this->fetchObject( $res );
1457
1458                 return $row ? ( strtolower( $row->default_transaction_read_only ) === 'on' ) : false;
1459         }
1460
1461         /**
1462          * @param string $lockName
1463          * @return string Integer
1464          */
1465         private function bigintFromLockName( $lockName ) {
1466                 return \Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1467         }
1468 }
1469
1470 /**
1471  * @deprecated since 1.29
1472  */
1473 class_alias( DatabasePostgres::class, 'DatabasePostgres' );