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