includes/libs/rdbms/database/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23 namespace Wikimedia\Rdbms;
  24
  25 use Wikimedia\Timestamp\ConvertibleTimestamp;
  26 use Wikimedia\WaitConditionLoop;
  27 use Wikimedia;
  28 use Exception;
  29
  30 /**
  31  * @ingroup Database
  32  */
  33 class DatabasePostgres extends Database {
  34         /** @var int|bool */
  35         protected $port;
  36
  37         /** @var resource */
  38         protected $lastResultHandle = null;
  39
  40         /** @var float|string */
  41         private $numericVersion = null;
  42         /** @var string Connect string to open a PostgreSQL connection */
  43         private $connectString;
  44         /** @var string */
  45         private $coreSchema;
  46         /** @var string */
  47         private $tempSchema;
  48         /** @var string[] Map of (reserved table name => alternate table name) */
  49         private $keywordTableMap = [];
  50
  51         /**
  52          * @see Database::__construct()
  53          * @param array $params Additional parameters include:
  54          *   - keywordTableMap : Map of reserved table names to alternative table names to use
  55          */
  56         public function __construct( array $params ) {
  57                 $this->port = $params['port'] ?? false;
  58                 $this->keywordTableMap = $params['keywordTableMap'] ?? [];
  59
  60                 parent::__construct( $params );
  61         }
  62
  63         public function getType() {
  64                 return 'postgres';
  65         }
  66
  67         public function implicitGroupby() {
  68                 return false;
  69         }
  70
  71         public function implicitOrderby() {
  72                 return false;
  73         }
  74
  75         public function hasConstraint( $name ) {
  76                 foreach ( $this->getCoreSchemas() as $schema ) {
  77                         $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
  78                                 "WHERE c.connamespace = n.oid AND conname = " .
  79                                 $this->addQuotes( $name ) . " AND n.nspname = " .
  80                                 $this->addQuotes( $schema );
  81                         $res = $this->doQuery( $sql );
  82                         if ( $res && $this->numRows( $res ) ) {
  83                                 return true;
  84                         }
  85                 }
  86                 return false;
  87         }
  88
  89         protected function open( $server, $user, $password, $dbName, $schema, $tablePrefix ) {
  90                 # Test for Postgres support, to avoid suppressed fatal error
  91                 if ( !function_exists( 'pg_connect' ) ) {
  92                         throw new DBConnectionError(
  93                                 $this,
  94                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
  95                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
  96                                 "webserver and database)\n"
  97                         );
  98                 }
  99
 100                 $this->server = $server;
 101                 $this->user = $user;
 102                 $this->password = $password;
 103
 104                 $connectVars = [
 105                         // pg_connect() user $user as the default database. Since a database is *required*,
 106                         // at least pick a "don't care" database that is more likely to exist. This case
 107                         // arrises when LoadBalancer::getConnection( $i, [], '' ) is used.
 108                         'dbname' => strlen( $dbName ) ? $dbName : 'postgres',
 109                         'user' => $user,
 110                         'password' => $password
 111                 ];
 112                 if ( $server != false && $server != '' ) {
 113                         $connectVars['host'] = $server;
 114                 }
 115                 if ( (int)$this->port > 0 ) {
 116                         $connectVars['port'] = (int)$this->port;
 117                 }
 118                 if ( $this->flags & self::DBO_SSL ) {
 119                         $connectVars['sslmode'] = 1;
 120                 }
 121
 122                 $this->connectString = $this->makeConnectionString( $connectVars );
 123                 $this->close();
 124                 $this->installErrorHandler();
 125
 126                 try {
 127                         // Use new connections to let LoadBalancer/LBFactory handle reuse
 128                         $this->conn = pg_connect( $this->connectString, PGSQL_CONNECT_FORCE_NEW );
 129                 } catch ( Exception $ex ) {
 130                         $this->restoreErrorHandler();
 131                         throw $ex;
 132                 }
 133
 134                 $phpError = $this->restoreErrorHandler();
 135
 136                 if ( !$this->conn ) {
 137                         $this->queryLogger->debug(
 138                                 "DB connection error\n" .
 139                                 "Server: $server, Database: $dbName, User: $user, Password: " .
 140                                 substr( $password, 0, 3 ) . "...\n"
 141                         );
 142                         $this->queryLogger->debug( $this->lastError() . "\n" );
 143                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 144                 }
 145
 146                 $this->opened = true;
 147
 148                 # If called from the command-line (e.g. importDump), only show errors
 149                 if ( $this->cliMode ) {
 150                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 151                 }
 152
 153                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 154                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 155                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 156                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 157                 $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 158
 159                 $this->determineCoreSchema( $schema );
 160                 $this->currentDomain = new DatabaseDomain( $dbName, $schema, $tablePrefix );
 161
 162                 return (bool)$this->conn;
 163         }
 164
 165         protected function relationSchemaQualifier() {
 166                 if ( $this->coreSchema === $this->currentDomain->getSchema() ) {
 167                         // The schema to be used is now in the search path; no need for explicit qualification
 168                         return '';
 169                 }
 170
 171                 return parent::relationSchemaQualifier();
 172         }
 173
 174         public function databasesAreIndependent() {
 175                 return true;
 176         }
 177
 178         public function doSelectDomain( DatabaseDomain $domain ) {
 179                 if ( $this->getDBname() !== $domain->getDatabase() ) {
 180                         // Postgres doesn't support selectDB in the same way MySQL does.
 181                         // So if the DB name doesn't match the open connection, open a new one
 182                         $this->open(
 183                                 $this->server,
 184                                 $this->user,
 185                                 $this->password,
 186                                 $domain->getDatabase(),
 187                                 $domain->getSchema(),
 188                                 $domain->getTablePrefix()
 189                         );
 190                 } else {
 191                         $this->currentDomain = $domain;
 192                 }
 193
 194                 return true;
 195         }
 196
 197         /**
 198          * @param string[] $vars
 199          * @return string
 200          */
 201         private function makeConnectionString( $vars ) {
 202                 $s = '';
 203                 foreach ( $vars as $name => $value ) {
 204                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 205                 }
 206
 207                 return $s;
 208         }
 209
 210         protected function closeConnection() {
 211                 return $this->conn ? pg_close( $this->conn ) : true;
 212         }
 213
 214         protected function isTransactableQuery( $sql ) {
 215                 return parent::isTransactableQuery( $sql ) &&
 216                         !preg_match( '/^SELECT\s+pg_(try_|)advisory_\w+\(/', $sql );
 217         }
 218
 219         /**
 220          * @param string $sql
 221          * @return bool|mixed|resource
 222          */
 223         public function doQuery( $sql ) {
 224                 $conn = $this->getBindingHandle();
 225
 226                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 227                 // Clear previously left over PQresult
 228                 while ( $res = pg_get_result( $conn ) ) {
 229                         pg_free_result( $res );
 230                 }
 231                 if ( pg_send_query( $conn, $sql ) === false ) {
 232                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 233                 }
 234                 $this->lastResultHandle = pg_get_result( $conn );
 235                 if ( pg_result_error( $this->lastResultHandle ) ) {
 236                         return false;
 237                 }
 238
 239                 return $this->lastResultHandle;
 240         }
 241
 242         protected function dumpError() {
 243                 $diags = [
 244                         PGSQL_DIAG_SEVERITY,
 245                         PGSQL_DIAG_SQLSTATE,
 246                         PGSQL_DIAG_MESSAGE_PRIMARY,
 247                         PGSQL_DIAG_MESSAGE_DETAIL,
 248                         PGSQL_DIAG_MESSAGE_HINT,
 249                         PGSQL_DIAG_STATEMENT_POSITION,
 250                         PGSQL_DIAG_INTERNAL_POSITION,
 251                         PGSQL_DIAG_INTERNAL_QUERY,
 252                         PGSQL_DIAG_CONTEXT,
 253                         PGSQL_DIAG_SOURCE_FILE,
 254                         PGSQL_DIAG_SOURCE_LINE,
 255                         PGSQL_DIAG_SOURCE_FUNCTION
 256                 ];
 257                 foreach ( $diags as $d ) {
 258                         $this->queryLogger->debug( sprintf( "PgSQL ERROR(%d): %s\n",
 259                                 $d, pg_result_error_field( $this->lastResultHandle, $d ) ) );
 260                 }
 261         }
 262
 263         public function freeResult( $res ) {
 264                 if ( $res instanceof ResultWrapper ) {
 265                         $res = $res->result;
 266                 }
 267                 Wikimedia\suppressWarnings();
 268                 $ok = pg_free_result( $res );
 269                 Wikimedia\restoreWarnings();
 270                 if ( !$ok ) {
 271                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 272                 }
 273         }
 274
 275         public function fetchObject( $res ) {
 276                 if ( $res instanceof ResultWrapper ) {
 277                         $res = $res->result;
 278                 }
 279                 Wikimedia\suppressWarnings();
 280                 $row = pg_fetch_object( $res );
 281                 Wikimedia\restoreWarnings();
 282                 # @todo FIXME: HACK HACK HACK HACK debug
 283
 284                 # @todo hashar: not sure if the following test really trigger if the object
 285                 #          fetching failed.
 286                 $conn = $this->getBindingHandle();
 287                 if ( pg_last_error( $conn ) ) {
 288                         throw new DBUnexpectedError(
 289                                 $this,
 290                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 291                         );
 292                 }
 293
 294                 return $row;
 295         }
 296
 297         public function fetchRow( $res ) {
 298                 if ( $res instanceof ResultWrapper ) {
 299                         $res = $res->result;
 300                 }
 301                 Wikimedia\suppressWarnings();
 302                 $row = pg_fetch_array( $res );
 303                 Wikimedia\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 $row;
 314         }
 315
 316         public function numRows( $res ) {
 317                 if ( $res === false ) {
 318                         return 0;
 319                 }
 320
 321                 if ( $res instanceof ResultWrapper ) {
 322                         $res = $res->result;
 323                 }
 324                 Wikimedia\suppressWarnings();
 325                 $n = pg_num_rows( $res );
 326                 Wikimedia\restoreWarnings();
 327
 328                 $conn = $this->getBindingHandle();
 329                 if ( pg_last_error( $conn ) ) {
 330                         throw new DBUnexpectedError(
 331                                 $this,
 332                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 333                         );
 334                 }
 335
 336                 return $n;
 337         }
 338
 339         public function numFields( $res ) {
 340                 if ( $res instanceof ResultWrapper ) {
 341                         $res = $res->result;
 342                 }
 343
 344                 return pg_num_fields( $res );
 345         }
 346
 347         public function fieldName( $res, $n ) {
 348                 if ( $res instanceof ResultWrapper ) {
 349                         $res = $res->result;
 350                 }
 351
 352                 return pg_field_name( $res, $n );
 353         }
 354
 355         public function insertId() {
 356                 $res = $this->query( "SELECT lastval()" );
 357                 $row = $this->fetchRow( $res );
 358                 return is_null( $row[0] ) ? null : (int)$row[0];
 359         }
 360
 361         public function dataSeek( $res, $row ) {
 362                 if ( $res instanceof ResultWrapper ) {
 363                         $res = $res->result;
 364                 }
 365
 366                 return pg_result_seek( $res, $row );
 367         }
 368
 369         public function lastError() {
 370                 if ( $this->conn ) {
 371                         if ( $this->lastResultHandle ) {
 372                                 return pg_result_error( $this->lastResultHandle );
 373                         } else {
 374                                 return pg_last_error();
 375                         }
 376                 }
 377
 378                 return $this->getLastPHPError() ?: 'No database connection';
 379         }
 380
 381         public function lastErrno() {
 382                 if ( $this->lastResultHandle ) {
 383                         return pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
 384                 } else {
 385                         return false;
 386                 }
 387         }
 388
 389         protected function fetchAffectedRowCount() {
 390                 if ( !$this->lastResultHandle ) {
 391                         return 0;
 392                 }
 393
 394                 return pg_affected_rows( $this->lastResultHandle );
 395         }
 396
 397         /**
 398          * Estimate rows in dataset
 399          * Returns estimated count, based on EXPLAIN output
 400          * This is not necessarily an accurate estimate, so use sparingly
 401          * Returns -1 if count cannot be found
 402          * Takes same arguments as Database::select()
 403          *
 404          * @param string $table
 405          * @param string $var
 406          * @param string $conds
 407          * @param string $fname
 408          * @param array $options
 409          * @param array $join_conds
 410          * @return int
 411          */
 412         public function estimateRowCount( $table, $var = '*', $conds = '',
 413                 $fname = __METHOD__, $options = [], $join_conds = []
 414         ) {
 415                 $conds = $this->normalizeConditions( $conds, $fname );
 416                 $column = $this->extractSingleFieldFromList( $var );
 417                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 418                         $conds[] = "$column IS NOT NULL";
 419                 }
 420
 421                 $options['EXPLAIN'] = true;
 422                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 423                 $rows = -1;
 424                 if ( $res ) {
 425                         $row = $this->fetchRow( $res );
 426                         $count = [];
 427                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 428                                 $rows = (int)$count[1];
 429                         }
 430                 }
 431
 432                 return $rows;
 433         }
 434
 435         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 436                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 437                 $res = $this->query( $sql, $fname );
 438                 if ( !$res ) {
 439                         return null;
 440                 }
 441                 foreach ( $res as $row ) {
 442                         if ( $row->indexname == $this->indexName( $index ) ) {
 443                                 return $row;
 444                         }
 445                 }
 446
 447                 return false;
 448         }
 449
 450         public function indexAttributes( $index, $schema = false ) {
 451                 if ( $schema === false ) {
 452                         $schemas = $this->getCoreSchemas();
 453                 } else {
 454                         $schemas = [ $schema ];
 455                 }
 456
 457                 $eindex = $this->addQuotes( $index );
 458
 459                 foreach ( $schemas as $schema ) {
 460                         $eschema = $this->addQuotes( $schema );
 461                         /*
 462                          * A subquery would be not needed if we didn't care about the order
 463                          * of attributes, but we do
 464                          */
 465                         $sql = <<<__INDEXATTR__
 466
 467                                 SELECT opcname,
 468                                         attname,
 469                                         i.indoption[s.g] as option,
 470                                         pg_am.amname
 471                                 FROM
 472                                         (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 473                                                 FROM
 474                                                         pg_index isub
 475                                                 JOIN pg_class cis
 476                                                         ON cis.oid=isub.indexrelid
 477                                                 JOIN pg_namespace ns
 478                                                         ON cis.relnamespace = ns.oid
 479                                                 WHERE cis.relname=$eindex AND ns.nspname=$eschema) AS s,
 480                                         pg_attribute,
 481                                         pg_opclass opcls,
 482                                         pg_am,
 483                                         pg_class ci
 484                                         JOIN pg_index i
 485                                                 ON ci.oid=i.indexrelid
 486                                         JOIN pg_class ct
 487                                                 ON ct.oid = i.indrelid
 488                                         JOIN pg_namespace n
 489                                                 ON ci.relnamespace = n.oid
 490                                         WHERE
 491                                                 ci.relname=$eindex AND n.nspname=$eschema
 492                                                 AND     attrelid = ct.oid
 493                                                 AND     i.indkey[s.g] = attnum
 494                                                 AND     i.indclass[s.g] = opcls.oid
 495                                                 AND     pg_am.oid = opcls.opcmethod
 496 __INDEXATTR__;
 497                         $res = $this->query( $sql, __METHOD__ );
 498                         $a = [];
 499                         if ( $res ) {
 500                                 foreach ( $res as $row ) {
 501                                         $a[] = [
 502                                                 $row->attname,
 503                                                 $row->opcname,
 504                                                 $row->amname,
 505                                                 $row->option ];
 506                                 }
 507                                 return $a;
 508                         }
 509                 }
 510                 return null;
 511         }
 512
 513         public function indexUnique( $table, $index, $fname = __METHOD__ ) {
 514                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 515                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 516                         $this->strencode( $this->indexName( $index ) ) .
 517                         ")'";
 518                 $res = $this->query( $sql, $fname );
 519                 if ( !$res ) {
 520                         return null;
 521                 }
 522
 523                 return $res->numRows() > 0;
 524         }
 525
 526         public function selectSQLText(
 527                 $table, $vars, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
 528         ) {
 529                 if ( is_string( $options ) ) {
 530                         $options = [ $options ];
 531                 }
 532
 533                 // Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 534                 // to the parent function to get the actual SQL text.
 535                 // In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 536                 // can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to
 537                 // do so causes a DB error. This wrapper checks which tables can be locked and adjusts it
 538                 // accordingly.
 539                 // MySQL uses "ORDER BY NULL" as an optimization hint, but that is illegal in PostgreSQL.
 540                 if ( is_array( $options ) ) {
 541                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 542                         if ( $forUpdateKey !== false && $join_conds ) {
 543                                 unset( $options[$forUpdateKey] );
 544                                 $options['FOR UPDATE'] = [];
 545
 546                                 $toCheck = $table;
 547                                 reset( $toCheck );
 548                                 while ( $toCheck ) {
 549                                         $alias = key( $toCheck );
 550                                         $name = $toCheck[$alias];
 551                                         unset( $toCheck[$alias] );
 552
 553                                         $hasAlias = !is_numeric( $alias );
 554                                         if ( !$hasAlias && is_string( $name ) ) {
 555                                                 $alias = $name;
 556                                         }
 557
 558                                         if ( !isset( $join_conds[$alias] ) ||
 559                                                 !preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_conds[$alias][0] )
 560                                         ) {
 561                                                 if ( is_array( $name ) ) {
 562                                                         // It's a parenthesized group, process all the tables inside the group.
 563                                                         $toCheck = array_merge( $toCheck, $name );
 564                                                 } else {
 565                                                         // Quote alias names so $this->tableName() won't mangle them
 566                                                         $options['FOR UPDATE'][] = $hasAlias ? $this->addIdentifierQuotes( $alias ) : $alias;
 567                                                 }
 568                                         }
 569                                 }
 570                         }
 571
 572                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 573                                 unset( $options['ORDER BY'] );
 574                         }
 575                 }
 576
 577                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 578         }
 579
 580         /** @inheritDoc */
 581         public function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 582                 if ( !count( $args ) ) {
 583                         return true;
 584                 }
 585
 586                 $table = $this->tableName( $table );
 587                 if ( !isset( $this->numericVersion ) ) {
 588                         $this->getServerVersion();
 589                 }
 590
 591                 if ( !is_array( $options ) ) {
 592                         $options = [ $options ];
 593                 }
 594
 595                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 596                         $rows = $args;
 597                         $keys = array_keys( $args[0] );
 598                 } else {
 599                         $rows = [ $args ];
 600                         $keys = array_keys( $args );
 601                 }
 602
 603                 $ignore = in_array( 'IGNORE', $options );
 604
 605                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 606
 607                 if ( $this->numericVersion >= 9.5 || !$ignore ) {
 608                         // No IGNORE or our PG has "ON CONFLICT DO NOTHING"
 609                         $first = true;
 610                         foreach ( $rows as $row ) {
 611                                 if ( $first ) {
 612                                         $first = false;
 613                                 } else {
 614                                         $sql .= ',';
 615                                 }
 616                                 $sql .= '(' . $this->makeList( $row ) . ')';
 617                         }
 618                         if ( $ignore ) {
 619                                 $sql .= ' ON CONFLICT DO NOTHING';
 620                         }
 621                         $this->query( $sql, $fname );
 622                 } else {
 623                         // Emulate IGNORE by doing each row individually, with savepoints
 624                         // to roll back as necessary.
 625                         $numrowsinserted = 0;
 626
 627                         $tok = $this->startAtomic( "$fname (outer)", self::ATOMIC_CANCELABLE );
 628                         try {
 629                                 foreach ( $rows as $row ) {
 630                                         $tempsql = $sql;
 631                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 632
 633                                         $this->startAtomic( "$fname (inner)", self::ATOMIC_CANCELABLE );
 634                                         try {
 635                                                 $this->query( $tempsql, $fname );
 636                                                 $this->endAtomic( "$fname (inner)" );
 637                                                 $numrowsinserted++;
 638                                         } catch ( DBQueryError $e ) {
 639                                                 $this->cancelAtomic( "$fname (inner)" );
 640                                                 // Our IGNORE is supposed to ignore duplicate key errors, but not others.
 641                                                 // (even though MySQL's version apparently ignores all errors)
 642                                                 if ( $e->errno !== '23505' ) {
 643                                                         throw $e;
 644                                                 }
 645                                         }
 646                                 }
 647                         } catch ( Exception $e ) {
 648                                 $this->cancelAtomic( "$fname (outer)", $tok );
 649                                 throw $e;
 650                         }
 651                         $this->endAtomic( "$fname (outer)" );
 652
 653                         // Set the affected row count for the whole operation
 654                         $this->affectedRowCount = $numrowsinserted;
 655                 }
 656
 657                 return true;
 658         }
 659
 660         protected function makeUpdateOptionsArray( $options ) {
 661                 if ( !is_array( $options ) ) {
 662                         $options = [ $options ];
 663                 }
 664
 665                 // PostgreSQL doesn't support anything like "ignore" for
 666                 // UPDATE.
 667                 $options = array_diff( $options, [ 'IGNORE' ] );
 668
 669                 return parent::makeUpdateOptionsArray( $options );
 670         }
 671
 672         /**
 673          * INSERT SELECT wrapper
 674          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 675          * Source items may be literals rather then field names, but strings should
 676          * be quoted with Database::addQuotes()
 677          * $conds may be "*" to copy the whole table
 678          * srcTable may be an array of tables.
 679          * @todo FIXME: Implement this a little better (separate select/insert)?
 680          *
 681          * @param string $destTable
 682          * @param array|string $srcTable
 683          * @param array $varMap
 684          * @param array $conds
 685          * @param string $fname
 686          * @param array $insertOptions
 687          * @param array $selectOptions
 688          * @param array $selectJoinConds
 689          */
 690         protected function nativeInsertSelect(
 691                 $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 692                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 693         ) {
 694                 if ( !is_array( $insertOptions ) ) {
 695                         $insertOptions = [ $insertOptions ];
 696                 }
 697
 698                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 699                         if ( $this->getServerVersion() >= 9.5 ) {
 700                                 // Use ON CONFLICT DO NOTHING if we have it for IGNORE
 701                                 $destTable = $this->tableName( $destTable );
 702
 703                                 $selectSql = $this->selectSQLText(
 704                                         $srcTable,
 705                                         array_values( $varMap ),
 706                                         $conds,
 707                                         $fname,
 708                                         $selectOptions,
 709                                         $selectJoinConds
 710                                 );
 711
 712                                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ') ' .
 713                                         $selectSql . ' ON CONFLICT DO NOTHING';
 714
 715                                 $this->query( $sql, $fname );
 716                         } else {
 717                                 // IGNORE and we don't have ON CONFLICT DO NOTHING, so just use the non-native version
 718                                 $this->nonNativeInsertSelect(
 719                                         $destTable, $srcTable, $varMap, $conds, $fname,
 720                                         $insertOptions, $selectOptions, $selectJoinConds
 721                                 );
 722                         }
 723                 } else {
 724                         parent::nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname,
 725                                 $insertOptions, $selectOptions, $selectJoinConds );
 726                 }
 727         }
 728
 729         public function tableName( $name, $format = 'quoted' ) {
 730                 // Replace reserved words with better ones
 731                 $name = $this->remappedTableName( $name );
 732
 733                 return parent::tableName( $name, $format );
 734         }
 735
 736         /**
 737          * @param string $name
 738          * @return string Value of $name or remapped name if $name is a reserved keyword
 739          */
 740         public function remappedTableName( $name ) {
 741                 return $this->keywordTableMap[$name] ?? $name;
 742         }
 743
 744         /**
 745          * @param string $name
 746          * @param string $format
 747          * @return string Qualified and encoded (if requested) table name
 748          */
 749         public function realTableName( $name, $format = 'quoted' ) {
 750                 return parent::tableName( $name, $format );
 751         }
 752
 753         public function nextSequenceValue( $seqName ) {
 754                 return new NextSequenceValue;
 755         }
 756
 757         /**
 758          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 759          *
 760          * @param string $seqName
 761          * @return int
 762          */
 763         public function currentSequenceValue( $seqName ) {
 764                 $safeseq = str_replace( "'", "''", $seqName );
 765                 $res = $this->query( "SELECT currval('$safeseq')" );
 766                 $row = $this->fetchRow( $res );
 767                 $currval = $row[0];
 768
 769                 return $currval;
 770         }
 771
 772         public function textFieldSize( $table, $field ) {
 773                 $table = $this->tableName( $table );
 774                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 775                         FROM pg_class c, pg_attribute a, pg_type t
 776                         WHERE relname='$table' AND a.attrelid=c.oid AND
 777                                 a.atttypid=t.oid and a.attname='$field'";
 778                 $res = $this->query( $sql );
 779                 $row = $this->fetchObject( $res );
 780                 if ( $row->ftype == 'varchar' ) {
 781                         $size = $row->size - 4;
 782                 } else {
 783                         $size = $row->size;
 784                 }
 785
 786                 return $size;
 787         }
 788
 789         public function limitResult( $sql, $limit, $offset = false ) {
 790                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 791         }
 792
 793         public function wasDeadlock() {
 794                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 795                 return $this->lastErrno() === '40P01';
 796         }
 797
 798         public function wasLockTimeout() {
 799                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 800                 return $this->lastErrno() === '55P03';
 801         }
 802
 803         public function wasConnectionError( $errno ) {
 804                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 805                 static $codes = [ '08000', '08003', '08006', '08001', '08004', '57P01', '57P03', '53300' ];
 806
 807                 return in_array( $errno, $codes, true );
 808         }
 809
 810         protected function wasKnownStatementRollbackError() {
 811                 return false; // transaction has to be rolled-back from error state
 812         }
 813
 814         public function duplicateTableStructure(
 815                 $oldName, $newName, $temporary = false, $fname = __METHOD__
 816         ) {
 817                 $newNameE = $this->addIdentifierQuotes( $newName );
 818                 $oldNameE = $this->addIdentifierQuotes( $oldName );
 819
 820                 $temporary = $temporary ? 'TEMPORARY' : '';
 821
 822                 $ret = $this->query( "CREATE $temporary TABLE $newNameE " .
 823                         "(LIKE $oldNameE INCLUDING DEFAULTS INCLUDING INDEXES)", $fname );
 824                 if ( !$ret ) {
 825                         return $ret;
 826                 }
 827
 828                 $res = $this->query( 'SELECT attname FROM pg_class c'
 829                         . ' JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 830                         . ' JOIN pg_attribute a ON (a.attrelid = c.oid)'
 831                         . ' JOIN pg_attrdef d ON (c.oid=d.adrelid and a.attnum=d.adnum)'
 832                         . ' WHERE relkind = \'r\''
 833                         . ' AND nspname = ' . $this->addQuotes( $this->getCoreSchema() )
 834                         . ' AND relname = ' . $this->addQuotes( $oldName )
 835                         . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 836                         $fname
 837                 );
 838                 $row = $this->fetchObject( $res );
 839                 if ( $row ) {
 840                         $field = $row->attname;
 841                         $newSeq = "{$newName}_{$field}_seq";
 842                         $fieldE = $this->addIdentifierQuotes( $field );
 843                         $newSeqE = $this->addIdentifierQuotes( $newSeq );
 844                         $newSeqQ = $this->addQuotes( $newSeq );
 845                         $this->query( "CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE", $fname );
 846                         $this->query(
 847                                 "ALTER TABLE $newNameE ALTER COLUMN $fieldE SET DEFAULT nextval({$newSeqQ}::regclass)",
 848                                 $fname
 849                         );
 850                 }
 851
 852                 return $ret;
 853         }
 854
 855         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
 856                 $table = $this->tableName( $table, 'raw' );
 857                 foreach ( $this->getCoreSchemas() as $schema ) {
 858                         $res = $this->query(
 859                                 'SELECT c.oid FROM pg_class c JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 860                                 . ' WHERE relkind = \'r\''
 861                                 . ' AND nspname = ' . $this->addQuotes( $schema )
 862                                 . ' AND relname = ' . $this->addQuotes( $table ),
 863                                 $fname
 864                         );
 865                         if ( !$res || !$this->numRows( $res ) ) {
 866                                 continue;
 867                         }
 868
 869                         $oid = $this->fetchObject( $res )->oid;
 870                         $res = $this->query( 'SELECT pg_get_expr(adbin, adrelid) AS adsrc FROM pg_attribute a'
 871                                 . ' JOIN pg_attrdef d ON (a.attrelid=d.adrelid and a.attnum=d.adnum)'
 872                                 . " WHERE a.attrelid = $oid"
 873                                 . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 874                                 $fname
 875                         );
 876                         $row = $this->fetchObject( $res );
 877                         if ( $row ) {
 878                                 $this->query(
 879                                         'SELECT ' . preg_replace( '/^nextval\((.+)\)$/', 'setval($1,1,false)', $row->adsrc ),
 880                                         $fname
 881                                 );
 882                                 return true;
 883                         }
 884                         return false;
 885                 }
 886
 887                 return false;
 888         }
 889
 890         /**
 891          * @suppress SecurityCheck-SQLInjection array_map not recognized T204911
 892          */
 893         public function listTables( $prefix = null, $fname = __METHOD__ ) {
 894                 $eschemas = implode( ',', array_map( [ $this, 'addQuotes' ], $this->getCoreSchemas() ) );
 895                 $result = $this->query(
 896                         "SELECT DISTINCT tablename FROM pg_tables WHERE schemaname IN ($eschemas)", $fname );
 897                 $endArray = [];
 898
 899                 foreach ( $result as $table ) {
 900                         $vars = get_object_vars( $table );
 901                         $table = array_pop( $vars );
 902                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
 903                                 $endArray[] = $table;
 904                         }
 905                 }
 906
 907                 return $endArray;
 908         }
 909
 910         public function timestamp( $ts = 0 ) {
 911                 $ct = new ConvertibleTimestamp( $ts );
 912
 913                 return $ct->getTimestamp( TS_POSTGRES );
 914         }
 915
 916         /**
 917          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
 918          * to https://secure.php.net/manual/en/ref.pgsql.php
 919          *
 920          * Parsing a postgres array can be a tricky problem, he's my
 921          * take on this, it handles multi-dimensional arrays plus
 922          * escaping using a nasty regexp to determine the limits of each
 923          * data-item.
 924          *
 925          * This should really be handled by PHP PostgreSQL module
 926          *
 927          * @since 1.19
 928          * @param string $text Postgreql array returned in a text form like {a,b}
 929          * @param string[] $output
 930          * @param int|bool $limit
 931          * @param int $offset
 932          * @return string[]
 933          */
 934         private function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
 935                 if ( $limit === false ) {
 936                         $limit = strlen( $text ) - 1;
 937                         $output = [];
 938                 }
 939                 if ( $text == '{}' ) {
 940                         return $output;
 941                 }
 942                 do {
 943                         if ( $text[$offset] != '{' ) {
 944                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
 945                                         $text, $match, 0, $offset );
 946                                 $offset += strlen( $match[0] );
 947                                 $output[] = ( $match[1][0] != '"'
 948                                         ? $match[1]
 949                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
 950                                 if ( $match[3] == '},' ) {
 951                                         return $output;
 952                                 }
 953                         } else {
 954                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
 955                         }
 956                 } while ( $limit > $offset );
 957
 958                 return $output;
 959         }
 960
 961         public function aggregateValue( $valuedata, $valuename = 'value' ) {
 962                 return $valuedata;
 963         }
 964
 965         public function getSoftwareLink() {
 966                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
 967         }
 968
 969         /**
 970          * Return current schema (executes SELECT current_schema())
 971          * Needs transaction
 972          *
 973          * @since 1.19
 974          * @return string Default schema for the current session
 975          */
 976         public function getCurrentSchema() {
 977                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
 978                 $row = $this->fetchRow( $res );
 979
 980                 return $row[0];
 981         }
 982
 983         /**
 984          * Return list of schemas which are accessible without schema name
 985          * This is list does not contain magic keywords like "$user"
 986          * Needs transaction
 987          *
 988          * @see getSearchPath()
 989          * @see setSearchPath()
 990          * @since 1.19
 991          * @return array List of actual schemas for the current sesson
 992          */
 993         public function getSchemas() {
 994                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
 995                 $row = $this->fetchRow( $res );
 996                 $schemas = [];
 997
 998                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
 999
1000                 return $this->pg_array_parse( $row[0], $schemas );
1001         }
1002
1003         /**
1004          * Return search patch for schemas
1005          * This is different from getSchemas() since it contain magic keywords
1006          * (like "$user").
1007          * Needs transaction
1008          *
1009          * @since 1.19
1010          * @return array How to search for table names schemas for the current user
1011          */
1012         public function getSearchPath() {
1013                 $res = $this->query( "SHOW search_path", __METHOD__ );
1014                 $row = $this->fetchRow( $res );
1015
1016                 /* PostgreSQL returns SHOW values as strings */
1017
1018                 return explode( ",", $row[0] );
1019         }
1020
1021         /**
1022          * Update search_path, values should already be sanitized
1023          * Values may contain magic keywords like "$user"
1024          * @since 1.19
1025          *
1026          * @param array $search_path List of schemas to be searched by default
1027          */
1028         private function setSearchPath( $search_path ) {
1029                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1030         }
1031
1032         /**
1033          * Determine default schema for the current application
1034          * Adjust this session schema search path if desired schema exists
1035          * and is not alread there.
1036          *
1037          * We need to have name of the core schema stored to be able
1038          * to query database metadata.
1039          *
1040          * This will be also called by the installer after the schema is created
1041          *
1042          * @since 1.19
1043          *
1044          * @param string $desiredSchema
1045          */
1046         public function determineCoreSchema( $desiredSchema ) {
1047                 $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
1048                 if ( $this->schemaExists( $desiredSchema ) ) {
1049                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1050                                 $this->coreSchema = $desiredSchema;
1051                                 $this->queryLogger->debug(
1052                                         "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1053                         } else {
1054                                 /**
1055                                  * Prepend our schema (e.g. 'mediawiki') in front
1056                                  * of the search path
1057                                  * Fixes T17816
1058                                  */
1059                                 $search_path = $this->getSearchPath();
1060                                 array_unshift( $search_path,
1061                                         $this->addIdentifierQuotes( $desiredSchema ) );
1062                                 $this->setSearchPath( $search_path );
1063                                 $this->coreSchema = $desiredSchema;
1064                                 $this->queryLogger->debug(
1065                                         "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1066                         }
1067                 } else {
1068                         $this->coreSchema = $this->getCurrentSchema();
1069                         $this->queryLogger->debug(
1070                                 "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1071                                 $this->coreSchema . "\"\n" );
1072                 }
1073                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1074                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
1075         }
1076
1077         /**
1078          * Return schema name for core application tables
1079          *
1080          * @since 1.19
1081          * @return string Core schema name
1082          */
1083         public function getCoreSchema() {
1084                 return $this->coreSchema;
1085         }
1086
1087         /**
1088          * Return schema names for temporary tables and core application tables
1089          *
1090          * @since 1.31
1091          * @return string[] schema names
1092          */
1093         public function getCoreSchemas() {
1094                 if ( $this->tempSchema ) {
1095                         return [ $this->tempSchema, $this->getCoreSchema() ];
1096                 }
1097
1098                 $res = $this->query(
1099                         "SELECT nspname FROM pg_catalog.pg_namespace n WHERE n.oid = pg_my_temp_schema()", __METHOD__
1100                 );
1101                 $row = $this->fetchObject( $res );
1102                 if ( $row ) {
1103                         $this->tempSchema = $row->nspname;
1104                         return [ $this->tempSchema, $this->getCoreSchema() ];
1105                 }
1106
1107                 return [ $this->getCoreSchema() ];
1108         }
1109
1110         public function getServerVersion() {
1111                 if ( !isset( $this->numericVersion ) ) {
1112                         $conn = $this->getBindingHandle();
1113                         $versionInfo = pg_version( $conn );
1114                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1115                                 // Old client, abort install
1116                                 $this->numericVersion = '7.3 or earlier';
1117                         } elseif ( isset( $versionInfo['server'] ) ) {
1118                                 // Normal client
1119                                 $this->numericVersion = $versionInfo['server'];
1120                         } else {
1121                                 // T18937: broken pgsql extension from PHP<5.3
1122                                 $this->numericVersion = pg_parameter_status( $conn, 'server_version' );
1123                         }
1124                 }
1125
1126                 return $this->numericVersion;
1127         }
1128
1129         /**
1130          * Query whether a given relation exists (in the given schema, or the
1131          * default mw one if not given)
1132          * @param string $table
1133          * @param array|string $types
1134          * @param bool|string $schema
1135          * @return bool
1136          */
1137         private function relationExists( $table, $types, $schema = false ) {
1138                 if ( !is_array( $types ) ) {
1139                         $types = [ $types ];
1140                 }
1141                 if ( $schema === false ) {
1142                         $schemas = $this->getCoreSchemas();
1143                 } else {
1144                         $schemas = [ $schema ];
1145                 }
1146                 $table = $this->realTableName( $table, 'raw' );
1147                 $etable = $this->addQuotes( $table );
1148                 foreach ( $schemas as $schema ) {
1149                         $eschema = $this->addQuotes( $schema );
1150                         $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1151                                 . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1152                                 . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1153                         $res = $this->query( $sql );
1154                         if ( $res && $res->numRows() ) {
1155                                 return true;
1156                         }
1157                 }
1158
1159                 return false;
1160         }
1161
1162         /**
1163          * For backward compatibility, this function checks both tables and views.
1164          * @param string $table
1165          * @param string $fname
1166          * @param bool|string $schema
1167          * @return bool
1168          */
1169         public function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1170                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1171         }
1172
1173         public function sequenceExists( $sequence, $schema = false ) {
1174                 return $this->relationExists( $sequence, 'S', $schema );
1175         }
1176
1177         public function triggerExists( $table, $trigger ) {
1178                 $q = <<<SQL
1179         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1180                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1181                         AND tgrelid=pg_class.oid
1182                         AND nspname=%s AND relname=%s AND tgname=%s
1183 SQL;
1184                 foreach ( $this->getCoreSchemas() as $schema ) {
1185                         $res = $this->query(
1186                                 sprintf(
1187                                         $q,
1188                                         $this->addQuotes( $schema ),
1189                                         $this->addQuotes( $table ),
1190                                         $this->addQuotes( $trigger )
1191                                 )
1192                         );
1193                         if ( $res && $res->numRows() ) {
1194                                 return true;
1195                         }
1196                 }
1197
1198                 return false;
1199         }
1200
1201         public function ruleExists( $table, $rule ) {
1202                 $exists = $this->selectField( 'pg_rules', 'rulename',
1203                         [
1204                                 'rulename' => $rule,
1205                                 'tablename' => $table,
1206                                 'schemaname' => $this->getCoreSchemas()
1207                         ]
1208                 );
1209
1210                 return $exists === $rule;
1211         }
1212
1213         public function constraintExists( $table, $constraint ) {
1214                 foreach ( $this->getCoreSchemas() as $schema ) {
1215                         $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1216                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1217                                 $this->addQuotes( $schema ),
1218                                 $this->addQuotes( $table ),
1219                                 $this->addQuotes( $constraint )
1220                         );
1221                         $res = $this->query( $sql );
1222                         if ( $res && $res->numRows() ) {
1223                                 return true;
1224                         }
1225                 }
1226                 return false;
1227         }
1228
1229         /**
1230          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1231          * @param string $schema
1232          * @return bool
1233          */
1234         public function schemaExists( $schema ) {
1235                 if ( !strlen( $schema ) ) {
1236                         return false; // short-circuit
1237                 }
1238
1239                 $exists = $this->selectField(
1240                         '"pg_catalog"."pg_namespace"', 1, [ 'nspname' => $schema ], __METHOD__ );
1241
1242                 return (bool)$exists;
1243         }
1244
1245         /**
1246          * Returns true if a given role (i.e. user) exists, false otherwise.
1247          * @param string $roleName
1248          * @return bool
1249          */
1250         public function roleExists( $roleName ) {
1251                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1252                         [ 'rolname' => $roleName ], __METHOD__ );
1253
1254                 return (bool)$exists;
1255         }
1256
1257         /**
1258          * @param string $table
1259          * @param string $field
1260          * @return PostgresField|null
1261          */
1262         public function fieldInfo( $table, $field ) {
1263                 return PostgresField::fromText( $this, $table, $field );
1264         }
1265
1266         /**
1267          * pg_field_type() wrapper
1268          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1269          * @param int $index Field number, starting from 0
1270          * @return string
1271          */
1272         public function fieldType( $res, $index ) {
1273                 if ( $res instanceof ResultWrapper ) {
1274                         $res = $res->result;
1275                 }
1276
1277                 return pg_field_type( $res, $index );
1278         }
1279
1280         public function encodeBlob( $b ) {
1281                 return new PostgresBlob( pg_escape_bytea( $b ) );
1282         }
1283
1284         public function decodeBlob( $b ) {
1285                 if ( $b instanceof PostgresBlob ) {
1286                         $b = $b->fetch();
1287                 } elseif ( $b instanceof Blob ) {
1288                         return $b->fetch();
1289                 }
1290
1291                 return pg_unescape_bytea( $b );
1292         }
1293
1294         public function strencode( $s ) {
1295                 // Should not be called by us
1296                 return pg_escape_string( $this->getBindingHandle(), (string)$s );
1297         }
1298
1299         public function addQuotes( $s ) {
1300                 $conn = $this->getBindingHandle();
1301
1302                 if ( is_null( $s ) ) {
1303                         return 'NULL';
1304                 } elseif ( is_bool( $s ) ) {
1305                         return intval( $s );
1306                 } elseif ( $s instanceof Blob ) {
1307                         if ( $s instanceof PostgresBlob ) {
1308                                 $s = $s->fetch();
1309                         } else {
1310                                 $s = pg_escape_bytea( $conn, $s->fetch() );
1311                         }
1312                         return "'$s'";
1313                 } elseif ( $s instanceof NextSequenceValue ) {
1314                         return 'DEFAULT';
1315                 }
1316
1317                 return "'" . pg_escape_string( $conn, (string)$s ) . "'";
1318         }
1319
1320         public function makeSelectOptions( $options ) {
1321                 $preLimitTail = $postLimitTail = '';
1322                 $startOpts = $useIndex = $ignoreIndex = '';
1323
1324                 $noKeyOptions = [];
1325                 foreach ( $options as $key => $option ) {
1326                         if ( is_numeric( $key ) ) {
1327                                 $noKeyOptions[$option] = true;
1328                         }
1329                 }
1330
1331                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1332
1333                 $preLimitTail .= $this->makeOrderBy( $options );
1334
1335                 if ( isset( $options['FOR UPDATE'] ) ) {
1336                         $postLimitTail .= ' FOR UPDATE OF ' .
1337                                 implode( ', ', array_map( [ $this, 'tableName' ], $options['FOR UPDATE'] ) );
1338                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1339                         $postLimitTail .= ' FOR UPDATE';
1340                 }
1341
1342                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1343                         $startOpts .= 'DISTINCT';
1344                 }
1345
1346                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1347         }
1348
1349         public function buildConcat( $stringList ) {
1350                 return implode( ' || ', $stringList );
1351         }
1352
1353         public function buildGroupConcatField(
1354                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1355         ) {
1356                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1357
1358                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1359         }
1360
1361         public function buildStringCast( $field ) {
1362                 return $field . '::text';
1363         }
1364
1365         public function streamStatementEnd( &$sql, &$newLine ) {
1366                 # Allow dollar quoting for function declarations
1367                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1368                         if ( $this->delimiter ) {
1369                                 $this->delimiter = false;
1370                         } else {
1371                                 $this->delimiter = ';';
1372                         }
1373                 }
1374
1375                 return parent::streamStatementEnd( $sql, $newLine );
1376         }
1377
1378         public function doLockTables( array $read, array $write, $method ) {
1379                 $tablesWrite = [];
1380                 foreach ( $write as $table ) {
1381                         $tablesWrite[] = $this->tableName( $table );
1382                 }
1383                 $tablesRead = [];
1384                 foreach ( $read as $table ) {
1385                         $tablesRead[] = $this->tableName( $table );
1386                 }
1387
1388                 // Acquire locks for the duration of the current transaction...
1389                 if ( $tablesWrite ) {
1390                         $this->query(
1391                                 'LOCK TABLE ONLY ' . implode( ',', $tablesWrite ) . ' IN EXCLUSIVE MODE',
1392                                 $method
1393                         );
1394                 }
1395                 if ( $tablesRead ) {
1396                         $this->query(
1397                                 'LOCK TABLE ONLY ' . implode( ',', $tablesRead ) . ' IN SHARE MODE',
1398                                 $method
1399                         );
1400                 }
1401
1402                 return true;
1403         }
1404
1405         public function lockIsFree( $lockName, $method ) {
1406                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1407                         return false; // already held
1408                 }
1409                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1410                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1411                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1412                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1413                 $row = $this->fetchObject( $result );
1414
1415                 return ( $row->lockstatus === 't' );
1416         }
1417
1418         public function lock( $lockName, $method, $timeout = 5 ) {
1419                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1420                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1421                 $loop = new WaitConditionLoop(
1422                         function () use ( $lockName, $key, $timeout, $method ) {
1423                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1424                                 $row = $this->fetchObject( $res );
1425                                 if ( $row->lockstatus === 't' ) {
1426                                         parent::lock( $lockName, $method, $timeout ); // record
1427                                         return true;
1428                                 }
1429
1430                                 return WaitConditionLoop::CONDITION_CONTINUE;
1431                         },
1432                         $timeout
1433                 );
1434
1435                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1436         }
1437
1438         public function unlock( $lockName, $method ) {
1439                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1440                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1441                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1442                 $row = $this->fetchObject( $result );
1443
1444                 if ( $row->lockstatus === 't' ) {
1445                         parent::unlock( $lockName, $method ); // record
1446                         return true;
1447                 }
1448
1449                 $this->queryLogger->debug( __METHOD__ . " failed to release lock\n" );
1450
1451                 return false;
1452         }
1453
1454         public function serverIsReadOnly() {
1455                 $res = $this->query( "SHOW default_transaction_read_only", __METHOD__ );
1456                 $row = $this->fetchObject( $res );
1457
1458                 return $row ? ( strtolower( $row->default_transaction_read_only ) === 'on' ) : false;
1459         }
1460
1461         /**
1462          * @param string $lockName
1463          * @return string Integer
1464          */
1465         private function bigintFromLockName( $lockName ) {
1466                 return \Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1467         }
1468 }
1469
1470 /**
1471  * @deprecated since 1.29
1472  */
1473 class_alias( DatabasePostgres::class, 'DatabasePostgres' );