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