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'] = 'require';
 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                 try {
 147                         // If called from the command-line (e.g. importDump), only show errors.
 148                         // No transaction should be open at this point, so the problem of the SET
 149                         // effects being rolled back should not be an issue.
 150                         // See https://www.postgresql.org/docs/8.3/sql-set.html
 151                         $variables = [];
 152                         if ( $this->cliMode ) {
 153                                 $variables['client_min_messages'] = 'ERROR';
 154                         }
 155                         $variables += [
 156                                 'client_encoding' => 'UTF8',
 157                                 'datestyle' => 'ISO, YMD',
 158                                 'timezone' => 'GMT',
 159                                 'standard_conforming_strings' => 'on',
 160                                 'bytea_output' => 'escape'
 161                         ];
 162                         foreach ( $variables as $var => $val ) {
 163                                 $this->query(
 164                                         'SET ' . $this->addIdentifierQuotes( $var ) . ' = ' . $this->addQuotes( $val ),
 165                                         __METHOD__,
 166                                         self::QUERY_IGNORE_DBO_TRX | self::QUERY_NO_RETRY
 167                                 );
 168                         }
 169
 170                         $this->determineCoreSchema( $schema );
 171                         $this->currentDomain = new DatabaseDomain( $dbName, $schema, $tablePrefix );
 172                 } catch ( Exception $e ) {
 173                         // Connection was not fully initialized and is not safe for use
 174                         $this->conn = false;
 175                 }
 176         }
 177
 178         protected function relationSchemaQualifier() {
 179                 if ( $this->coreSchema === $this->currentDomain->getSchema() ) {
 180                         // The schema to be used is now in the search path; no need for explicit qualification
 181                         return '';
 182                 }
 183
 184                 return parent::relationSchemaQualifier();
 185         }
 186
 187         public function databasesAreIndependent() {
 188                 return true;
 189         }
 190
 191         public function doSelectDomain( DatabaseDomain $domain ) {
 192                 if ( $this->getDBname() !== $domain->getDatabase() ) {
 193                         // Postgres doesn't support selectDB in the same way MySQL does.
 194                         // So if the DB name doesn't match the open connection, open a new one
 195                         $this->open(
 196                                 $this->server,
 197                                 $this->user,
 198                                 $this->password,
 199                                 $domain->getDatabase(),
 200                                 $domain->getSchema(),
 201                                 $domain->getTablePrefix()
 202                         );
 203                 } else {
 204                         $this->currentDomain = $domain;
 205                 }
 206
 207                 return true;
 208         }
 209
 210         /**
 211          * @param string[] $vars
 212          * @return string
 213          */
 214         private function makeConnectionString( $vars ) {
 215                 $s = '';
 216                 foreach ( $vars as $name => $value ) {
 217                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 218                 }
 219
 220                 return $s;
 221         }
 222
 223         protected function closeConnection() {
 224                 return $this->conn ? pg_close( $this->conn ) : true;
 225         }
 226
 227         protected function isTransactableQuery( $sql ) {
 228                 return parent::isTransactableQuery( $sql ) &&
 229                         !preg_match( '/^SELECT\s+pg_(try_|)advisory_\w+\(/', $sql );
 230         }
 231
 232         /**
 233          * @param string $sql
 234          * @return bool|mixed|resource
 235          */
 236         public function doQuery( $sql ) {
 237                 $conn = $this->getBindingHandle();
 238
 239                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 240                 // Clear previously left over PQresult
 241                 while ( $res = pg_get_result( $conn ) ) {
 242                         pg_free_result( $res );
 243                 }
 244                 if ( pg_send_query( $conn, $sql ) === false ) {
 245                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 246                 }
 247                 $this->lastResultHandle = pg_get_result( $conn );
 248                 if ( pg_result_error( $this->lastResultHandle ) ) {
 249                         return false;
 250                 }
 251
 252                 return $this->lastResultHandle;
 253         }
 254
 255         protected function dumpError() {
 256                 $diags = [
 257                         PGSQL_DIAG_SEVERITY,
 258                         PGSQL_DIAG_SQLSTATE,
 259                         PGSQL_DIAG_MESSAGE_PRIMARY,
 260                         PGSQL_DIAG_MESSAGE_DETAIL,
 261                         PGSQL_DIAG_MESSAGE_HINT,
 262                         PGSQL_DIAG_STATEMENT_POSITION,
 263                         PGSQL_DIAG_INTERNAL_POSITION,
 264                         PGSQL_DIAG_INTERNAL_QUERY,
 265                         PGSQL_DIAG_CONTEXT,
 266                         PGSQL_DIAG_SOURCE_FILE,
 267                         PGSQL_DIAG_SOURCE_LINE,
 268                         PGSQL_DIAG_SOURCE_FUNCTION
 269                 ];
 270                 foreach ( $diags as $d ) {
 271                         $this->queryLogger->debug( sprintf( "PgSQL ERROR(%d): %s\n",
 272                                 $d, pg_result_error_field( $this->lastResultHandle, $d ) ) );
 273                 }
 274         }
 275
 276         public function freeResult( $res ) {
 277                 if ( $res instanceof ResultWrapper ) {
 278                         $res = $res->result;
 279                 }
 280                 Wikimedia\suppressWarnings();
 281                 $ok = pg_free_result( $res );
 282                 Wikimedia\restoreWarnings();
 283                 if ( !$ok ) {
 284                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 285                 }
 286         }
 287
 288         public function fetchObject( $res ) {
 289                 if ( $res instanceof ResultWrapper ) {
 290                         $res = $res->result;
 291                 }
 292                 Wikimedia\suppressWarnings();
 293                 $row = pg_fetch_object( $res );
 294                 Wikimedia\restoreWarnings();
 295                 # @todo FIXME: HACK HACK HACK HACK debug
 296
 297                 # @todo hashar: not sure if the following test really trigger if the object
 298                 #          fetching failed.
 299                 $conn = $this->getBindingHandle();
 300                 if ( pg_last_error( $conn ) ) {
 301                         throw new DBUnexpectedError(
 302                                 $this,
 303                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 304                         );
 305                 }
 306
 307                 return $row;
 308         }
 309
 310         public function fetchRow( $res ) {
 311                 if ( $res instanceof ResultWrapper ) {
 312                         $res = $res->result;
 313                 }
 314                 Wikimedia\suppressWarnings();
 315                 $row = pg_fetch_array( $res );
 316                 Wikimedia\restoreWarnings();
 317
 318                 $conn = $this->getBindingHandle();
 319                 if ( pg_last_error( $conn ) ) {
 320                         throw new DBUnexpectedError(
 321                                 $this,
 322                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 323                         );
 324                 }
 325
 326                 return $row;
 327         }
 328
 329         public function numRows( $res ) {
 330                 if ( $res === false ) {
 331                         return 0;
 332                 }
 333
 334                 if ( $res instanceof ResultWrapper ) {
 335                         $res = $res->result;
 336                 }
 337                 Wikimedia\suppressWarnings();
 338                 $n = pg_num_rows( $res );
 339                 Wikimedia\restoreWarnings();
 340
 341                 $conn = $this->getBindingHandle();
 342                 if ( pg_last_error( $conn ) ) {
 343                         throw new DBUnexpectedError(
 344                                 $this,
 345                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 346                         );
 347                 }
 348
 349                 return $n;
 350         }
 351
 352         public function numFields( $res ) {
 353                 if ( $res instanceof ResultWrapper ) {
 354                         $res = $res->result;
 355                 }
 356
 357                 return pg_num_fields( $res );
 358         }
 359
 360         public function fieldName( $res, $n ) {
 361                 if ( $res instanceof ResultWrapper ) {
 362                         $res = $res->result;
 363                 }
 364
 365                 return pg_field_name( $res, $n );
 366         }
 367
 368         public function insertId() {
 369                 $res = $this->query( "SELECT lastval()" );
 370                 $row = $this->fetchRow( $res );
 371                 return is_null( $row[0] ) ? null : (int)$row[0];
 372         }
 373
 374         public function dataSeek( $res, $row ) {
 375                 if ( $res instanceof ResultWrapper ) {
 376                         $res = $res->result;
 377                 }
 378
 379                 return pg_result_seek( $res, $row );
 380         }
 381
 382         public function lastError() {
 383                 if ( $this->conn ) {
 384                         if ( $this->lastResultHandle ) {
 385                                 return pg_result_error( $this->lastResultHandle );
 386                         } else {
 387                                 return pg_last_error();
 388                         }
 389                 }
 390
 391                 return $this->getLastPHPError() ?: 'No database connection';
 392         }
 393
 394         public function lastErrno() {
 395                 if ( $this->lastResultHandle ) {
 396                         return pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
 397                 } else {
 398                         return false;
 399                 }
 400         }
 401
 402         protected function fetchAffectedRowCount() {
 403                 if ( !$this->lastResultHandle ) {
 404                         return 0;
 405                 }
 406
 407                 return pg_affected_rows( $this->lastResultHandle );
 408         }
 409
 410         /**
 411          * Estimate rows in dataset
 412          * Returns estimated count, based on EXPLAIN output
 413          * This is not necessarily an accurate estimate, so use sparingly
 414          * Returns -1 if count cannot be found
 415          * Takes same arguments as Database::select()
 416          *
 417          * @param string $table
 418          * @param string $var
 419          * @param string $conds
 420          * @param string $fname
 421          * @param array $options
 422          * @param array $join_conds
 423          * @return int
 424          */
 425         public function estimateRowCount( $table, $var = '*', $conds = '',
 426                 $fname = __METHOD__, $options = [], $join_conds = []
 427         ) {
 428                 $conds = $this->normalizeConditions( $conds, $fname );
 429                 $column = $this->extractSingleFieldFromList( $var );
 430                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 431                         $conds[] = "$column IS NOT NULL";
 432                 }
 433
 434                 $options['EXPLAIN'] = true;
 435                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 436                 $rows = -1;
 437                 if ( $res ) {
 438                         $row = $this->fetchRow( $res );
 439                         $count = [];
 440                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 441                                 $rows = (int)$count[1];
 442                         }
 443                 }
 444
 445                 return $rows;
 446         }
 447
 448         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 449                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 450                 $res = $this->query( $sql, $fname );
 451                 if ( !$res ) {
 452                         return null;
 453                 }
 454                 foreach ( $res as $row ) {
 455                         if ( $row->indexname == $this->indexName( $index ) ) {
 456                                 return $row;
 457                         }
 458                 }
 459
 460                 return false;
 461         }
 462
 463         public function indexAttributes( $index, $schema = false ) {
 464                 if ( $schema === false ) {
 465                         $schemas = $this->getCoreSchemas();
 466                 } else {
 467                         $schemas = [ $schema ];
 468                 }
 469
 470                 $eindex = $this->addQuotes( $index );
 471
 472                 foreach ( $schemas as $schema ) {
 473                         $eschema = $this->addQuotes( $schema );
 474                         /*
 475                          * A subquery would be not needed if we didn't care about the order
 476                          * of attributes, but we do
 477                          */
 478                         $sql = <<<__INDEXATTR__
 479
 480                                 SELECT opcname,
 481                                         attname,
 482                                         i.indoption[s.g] as option,
 483                                         pg_am.amname
 484                                 FROM
 485                                         (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 486                                                 FROM
 487                                                         pg_index isub
 488                                                 JOIN pg_class cis
 489                                                         ON cis.oid=isub.indexrelid
 490                                                 JOIN pg_namespace ns
 491                                                         ON cis.relnamespace = ns.oid
 492                                                 WHERE cis.relname=$eindex AND ns.nspname=$eschema) AS s,
 493                                         pg_attribute,
 494                                         pg_opclass opcls,
 495                                         pg_am,
 496                                         pg_class ci
 497                                         JOIN pg_index i
 498                                                 ON ci.oid=i.indexrelid
 499                                         JOIN pg_class ct
 500                                                 ON ct.oid = i.indrelid
 501                                         JOIN pg_namespace n
 502                                                 ON ci.relnamespace = n.oid
 503                                         WHERE
 504                                                 ci.relname=$eindex AND n.nspname=$eschema
 505                                                 AND     attrelid = ct.oid
 506                                                 AND     i.indkey[s.g] = attnum
 507                                                 AND     i.indclass[s.g] = opcls.oid
 508                                                 AND     pg_am.oid = opcls.opcmethod
 509 __INDEXATTR__;
 510                         $res = $this->query( $sql, __METHOD__ );
 511                         $a = [];
 512                         if ( $res ) {
 513                                 foreach ( $res as $row ) {
 514                                         $a[] = [
 515                                                 $row->attname,
 516                                                 $row->opcname,
 517                                                 $row->amname,
 518                                                 $row->option ];
 519                                 }
 520                                 return $a;
 521                         }
 522                 }
 523                 return null;
 524         }
 525
 526         public function indexUnique( $table, $index, $fname = __METHOD__ ) {
 527                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 528                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 529                         $this->strencode( $this->indexName( $index ) ) .
 530                         ")'";
 531                 $res = $this->query( $sql, $fname );
 532                 if ( !$res ) {
 533                         return null;
 534                 }
 535
 536                 return $res->numRows() > 0;
 537         }
 538
 539         public function selectSQLText(
 540                 $table, $vars, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
 541         ) {
 542                 if ( is_string( $options ) ) {
 543                         $options = [ $options ];
 544                 }
 545
 546                 // Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 547                 // to the parent function to get the actual SQL text.
 548                 // In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 549                 // can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to
 550                 // do so causes a DB error. This wrapper checks which tables can be locked and adjusts it
 551                 // accordingly.
 552                 // MySQL uses "ORDER BY NULL" as an optimization hint, but that is illegal in PostgreSQL.
 553                 if ( is_array( $options ) ) {
 554                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 555                         if ( $forUpdateKey !== false && $join_conds ) {
 556                                 unset( $options[$forUpdateKey] );
 557                                 $options['FOR UPDATE'] = [];
 558
 559                                 $toCheck = $table;
 560                                 reset( $toCheck );
 561                                 while ( $toCheck ) {
 562                                         $alias = key( $toCheck );
 563                                         $name = $toCheck[$alias];
 564                                         unset( $toCheck[$alias] );
 565
 566                                         $hasAlias = !is_numeric( $alias );
 567                                         if ( !$hasAlias && is_string( $name ) ) {
 568                                                 $alias = $name;
 569                                         }
 570
 571                                         if ( !isset( $join_conds[$alias] ) ||
 572                                                 !preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_conds[$alias][0] )
 573                                         ) {
 574                                                 if ( is_array( $name ) ) {
 575                                                         // It's a parenthesized group, process all the tables inside the group.
 576                                                         $toCheck = array_merge( $toCheck, $name );
 577                                                 } else {
 578                                                         // Quote alias names so $this->tableName() won't mangle them
 579                                                         $options['FOR UPDATE'][] = $hasAlias ? $this->addIdentifierQuotes( $alias ) : $alias;
 580                                                 }
 581                                         }
 582                                 }
 583                         }
 584
 585                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 586                                 unset( $options['ORDER BY'] );
 587                         }
 588                 }
 589
 590                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 591         }
 592
 593         /** @inheritDoc */
 594         public function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 595                 if ( !count( $args ) ) {
 596                         return true;
 597                 }
 598
 599                 $table = $this->tableName( $table );
 600                 if ( !isset( $this->numericVersion ) ) {
 601                         $this->getServerVersion();
 602                 }
 603
 604                 if ( !is_array( $options ) ) {
 605                         $options = [ $options ];
 606                 }
 607
 608                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 609                         $rows = $args;
 610                         $keys = array_keys( $args[0] );
 611                 } else {
 612                         $rows = [ $args ];
 613                         $keys = array_keys( $args );
 614                 }
 615
 616                 $ignore = in_array( 'IGNORE', $options );
 617
 618                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 619
 620                 if ( $this->numericVersion >= 9.5 || !$ignore ) {
 621                         // No IGNORE or our PG has "ON CONFLICT DO NOTHING"
 622                         $first = true;
 623                         foreach ( $rows as $row ) {
 624                                 if ( $first ) {
 625                                         $first = false;
 626                                 } else {
 627                                         $sql .= ',';
 628                                 }
 629                                 $sql .= '(' . $this->makeList( $row ) . ')';
 630                         }
 631                         if ( $ignore ) {
 632                                 $sql .= ' ON CONFLICT DO NOTHING';
 633                         }
 634                         $this->query( $sql, $fname );
 635                 } else {
 636                         // Emulate IGNORE by doing each row individually, with savepoints
 637                         // to roll back as necessary.
 638                         $numrowsinserted = 0;
 639
 640                         $tok = $this->startAtomic( "$fname (outer)", self::ATOMIC_CANCELABLE );
 641                         try {
 642                                 foreach ( $rows as $row ) {
 643                                         $tempsql = $sql;
 644                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 645
 646                                         $this->startAtomic( "$fname (inner)", self::ATOMIC_CANCELABLE );
 647                                         try {
 648                                                 $this->query( $tempsql, $fname );
 649                                                 $this->endAtomic( "$fname (inner)" );
 650                                                 $numrowsinserted++;
 651                                         } catch ( DBQueryError $e ) {
 652                                                 $this->cancelAtomic( "$fname (inner)" );
 653                                                 // Our IGNORE is supposed to ignore duplicate key errors, but not others.
 654                                                 // (even though MySQL's version apparently ignores all errors)
 655                                                 if ( $e->errno !== '23505' ) {
 656                                                         throw $e;
 657                                                 }
 658                                         }
 659                                 }
 660                         } catch ( Exception $e ) {
 661                                 $this->cancelAtomic( "$fname (outer)", $tok );
 662                                 throw $e;
 663                         }
 664                         $this->endAtomic( "$fname (outer)" );
 665
 666                         // Set the affected row count for the whole operation
 667                         $this->affectedRowCount = $numrowsinserted;
 668                 }
 669
 670                 return true;
 671         }
 672
 673         protected function makeUpdateOptionsArray( $options ) {
 674                 if ( !is_array( $options ) ) {
 675                         $options = [ $options ];
 676                 }
 677
 678                 // PostgreSQL doesn't support anything like "ignore" for
 679                 // UPDATE.
 680                 $options = array_diff( $options, [ 'IGNORE' ] );
 681
 682                 return parent::makeUpdateOptionsArray( $options );
 683         }
 684
 685         /**
 686          * INSERT SELECT wrapper
 687          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 688          * Source items may be literals rather then field names, but strings should
 689          * be quoted with Database::addQuotes()
 690          * $conds may be "*" to copy the whole table
 691          * srcTable may be an array of tables.
 692          * @todo FIXME: Implement this a little better (separate select/insert)?
 693          *
 694          * @param string $destTable
 695          * @param array|string $srcTable
 696          * @param array $varMap
 697          * @param array $conds
 698          * @param string $fname
 699          * @param array $insertOptions
 700          * @param array $selectOptions
 701          * @param array $selectJoinConds
 702          */
 703         protected function nativeInsertSelect(
 704                 $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 705                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 706         ) {
 707                 if ( !is_array( $insertOptions ) ) {
 708                         $insertOptions = [ $insertOptions ];
 709                 }
 710
 711                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 712                         if ( $this->getServerVersion() >= 9.5 ) {
 713                                 // Use ON CONFLICT DO NOTHING if we have it for IGNORE
 714                                 $destTable = $this->tableName( $destTable );
 715
 716                                 $selectSql = $this->selectSQLText(
 717                                         $srcTable,
 718                                         array_values( $varMap ),
 719                                         $conds,
 720                                         $fname,
 721                                         $selectOptions,
 722                                         $selectJoinConds
 723                                 );
 724
 725                                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ') ' .
 726                                         $selectSql . ' ON CONFLICT DO NOTHING';
 727
 728                                 $this->query( $sql, $fname );
 729                         } else {
 730                                 // IGNORE and we don't have ON CONFLICT DO NOTHING, so just use the non-native version
 731                                 $this->nonNativeInsertSelect(
 732                                         $destTable, $srcTable, $varMap, $conds, $fname,
 733                                         $insertOptions, $selectOptions, $selectJoinConds
 734                                 );
 735                         }
 736                 } else {
 737                         parent::nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname,
 738                                 $insertOptions, $selectOptions, $selectJoinConds );
 739                 }
 740         }
 741
 742         public function tableName( $name, $format = 'quoted' ) {
 743                 // Replace reserved words with better ones
 744                 $name = $this->remappedTableName( $name );
 745
 746                 return parent::tableName( $name, $format );
 747         }
 748
 749         /**
 750          * @param string $name
 751          * @return string Value of $name or remapped name if $name is a reserved keyword
 752          */
 753         public function remappedTableName( $name ) {
 754                 return $this->keywordTableMap[$name] ?? $name;
 755         }
 756
 757         /**
 758          * @param string $name
 759          * @param string $format
 760          * @return string Qualified and encoded (if requested) table name
 761          */
 762         public function realTableName( $name, $format = 'quoted' ) {
 763                 return parent::tableName( $name, $format );
 764         }
 765
 766         public function nextSequenceValue( $seqName ) {
 767                 return new NextSequenceValue;
 768         }
 769
 770         /**
 771          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 772          *
 773          * @param string $seqName
 774          * @return int
 775          */
 776         public function currentSequenceValue( $seqName ) {
 777                 $safeseq = str_replace( "'", "''", $seqName );
 778                 $res = $this->query( "SELECT currval('$safeseq')" );
 779                 $row = $this->fetchRow( $res );
 780                 $currval = $row[0];
 781
 782                 return $currval;
 783         }
 784
 785         public function textFieldSize( $table, $field ) {
 786                 $table = $this->tableName( $table );
 787                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 788                         FROM pg_class c, pg_attribute a, pg_type t
 789                         WHERE relname='$table' AND a.attrelid=c.oid AND
 790                                 a.atttypid=t.oid and a.attname='$field'";
 791                 $res = $this->query( $sql );
 792                 $row = $this->fetchObject( $res );
 793                 if ( $row->ftype == 'varchar' ) {
 794                         $size = $row->size - 4;
 795                 } else {
 796                         $size = $row->size;
 797                 }
 798
 799                 return $size;
 800         }
 801
 802         public function limitResult( $sql, $limit, $offset = false ) {
 803                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 804         }
 805
 806         public function wasDeadlock() {
 807                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 808                 return $this->lastErrno() === '40P01';
 809         }
 810
 811         public function wasLockTimeout() {
 812                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 813                 return $this->lastErrno() === '55P03';
 814         }
 815
 816         public function wasConnectionError( $errno ) {
 817                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 818                 static $codes = [ '08000', '08003', '08006', '08001', '08004', '57P01', '57P03', '53300' ];
 819
 820                 return in_array( $errno, $codes, true );
 821         }
 822
 823         protected function wasKnownStatementRollbackError() {
 824                 return false; // transaction has to be rolled-back from error state
 825         }
 826
 827         public function duplicateTableStructure(
 828                 $oldName, $newName, $temporary = false, $fname = __METHOD__
 829         ) {
 830                 $newNameE = $this->addIdentifierQuotes( $newName );
 831                 $oldNameE = $this->addIdentifierQuotes( $oldName );
 832
 833                 $temporary = $temporary ? 'TEMPORARY' : '';
 834
 835                 $ret = $this->query(
 836                         "CREATE $temporary TABLE $newNameE " .
 837                                 "(LIKE $oldNameE INCLUDING DEFAULTS INCLUDING INDEXES)",
 838                         $fname,
 839                         $this::QUERY_PSEUDO_PERMANENT
 840                 );
 841                 if ( !$ret ) {
 842                         return $ret;
 843                 }
 844
 845                 $res = $this->query( 'SELECT attname FROM pg_class c'
 846                         . ' JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 847                         . ' JOIN pg_attribute a ON (a.attrelid = c.oid)'
 848                         . ' JOIN pg_attrdef d ON (c.oid=d.adrelid and a.attnum=d.adnum)'
 849                         . ' WHERE relkind = \'r\''
 850                         . ' AND nspname = ' . $this->addQuotes( $this->getCoreSchema() )
 851                         . ' AND relname = ' . $this->addQuotes( $oldName )
 852                         . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 853                         $fname
 854                 );
 855                 $row = $this->fetchObject( $res );
 856                 if ( $row ) {
 857                         $field = $row->attname;
 858                         $newSeq = "{$newName}_{$field}_seq";
 859                         $fieldE = $this->addIdentifierQuotes( $field );
 860                         $newSeqE = $this->addIdentifierQuotes( $newSeq );
 861                         $newSeqQ = $this->addQuotes( $newSeq );
 862                         $this->query(
 863                                 "CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE",
 864                                 $fname
 865                         );
 866                         $this->query(
 867                                 "ALTER TABLE $newNameE ALTER COLUMN $fieldE SET DEFAULT nextval({$newSeqQ}::regclass)",
 868                                 $fname
 869                         );
 870                 }
 871
 872                 return $ret;
 873         }
 874
 875         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
 876                 $table = $this->tableName( $table, 'raw' );
 877                 foreach ( $this->getCoreSchemas() as $schema ) {
 878                         $res = $this->query(
 879                                 'SELECT c.oid FROM pg_class c JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 880                                 . ' WHERE relkind = \'r\''
 881                                 . ' AND nspname = ' . $this->addQuotes( $schema )
 882                                 . ' AND relname = ' . $this->addQuotes( $table ),
 883                                 $fname
 884                         );
 885                         if ( !$res || !$this->numRows( $res ) ) {
 886                                 continue;
 887                         }
 888
 889                         $oid = $this->fetchObject( $res )->oid;
 890                         $res = $this->query( 'SELECT pg_get_expr(adbin, adrelid) AS adsrc FROM pg_attribute a'
 891                                 . ' JOIN pg_attrdef d ON (a.attrelid=d.adrelid and a.attnum=d.adnum)'
 892                                 . " WHERE a.attrelid = $oid"
 893                                 . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 894                                 $fname
 895                         );
 896                         $row = $this->fetchObject( $res );
 897                         if ( $row ) {
 898                                 $this->query(
 899                                         'SELECT ' . preg_replace( '/^nextval\((.+)\)$/', 'setval($1,1,false)', $row->adsrc ),
 900                                         $fname
 901                                 );
 902                                 return true;
 903                         }
 904                         return false;
 905                 }
 906
 907                 return false;
 908         }
 909
 910         /**
 911          * @suppress SecurityCheck-SQLInjection array_map not recognized T204911
 912          */
 913         public function listTables( $prefix = null, $fname = __METHOD__ ) {
 914                 $eschemas = implode( ',', array_map( [ $this, 'addQuotes' ], $this->getCoreSchemas() ) );
 915                 $result = $this->query(
 916                         "SELECT DISTINCT tablename FROM pg_tables WHERE schemaname IN ($eschemas)", $fname );
 917                 $endArray = [];
 918
 919                 foreach ( $result as $table ) {
 920                         $vars = get_object_vars( $table );
 921                         $table = array_pop( $vars );
 922                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
 923                                 $endArray[] = $table;
 924                         }
 925                 }
 926
 927                 return $endArray;
 928         }
 929
 930         public function timestamp( $ts = 0 ) {
 931                 $ct = new ConvertibleTimestamp( $ts );
 932
 933                 return $ct->getTimestamp( TS_POSTGRES );
 934         }
 935
 936         /**
 937          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
 938          * to https://www.php.net/manual/en/ref.pgsql.php
 939          *
 940          * Parsing a postgres array can be a tricky problem, he's my
 941          * take on this, it handles multi-dimensional arrays plus
 942          * escaping using a nasty regexp to determine the limits of each
 943          * data-item.
 944          *
 945          * This should really be handled by PHP PostgreSQL module
 946          *
 947          * @since 1.19
 948          * @param string $text Postgreql array returned in a text form like {a,b}
 949          * @param string[] $output
 950          * @param int|bool $limit
 951          * @param int $offset
 952          * @return string[]
 953          */
 954         private function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
 955                 if ( $limit === false ) {
 956                         $limit = strlen( $text ) - 1;
 957                         $output = [];
 958                 }
 959                 if ( $text == '{}' ) {
 960                         return $output;
 961                 }
 962                 do {
 963                         if ( $text[$offset] != '{' ) {
 964                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
 965                                         $text, $match, 0, $offset );
 966                                 $offset += strlen( $match[0] );
 967                                 $output[] = ( $match[1][0] != '"'
 968                                         ? $match[1]
 969                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
 970                                 if ( $match[3] == '},' ) {
 971                                         return $output;
 972                                 }
 973                         } else {
 974                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
 975                         }
 976                 } while ( $limit > $offset );
 977
 978                 return $output;
 979         }
 980
 981         public function aggregateValue( $valuedata, $valuename = 'value' ) {
 982                 return $valuedata;
 983         }
 984
 985         public function getSoftwareLink() {
 986                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
 987         }
 988
 989         /**
 990          * Return current schema (executes SELECT current_schema())
 991          * Needs transaction
 992          *
 993          * @since 1.19
 994          * @return string Default schema for the current session
 995          */
 996         public function getCurrentSchema() {
 997                 $res = $this->query( "SELECT current_schema()", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 998                 $row = $this->fetchRow( $res );
 999
1000                 return $row[0];
1001         }
1002
1003         /**
1004          * Return list of schemas which are accessible without schema name
1005          * This is list does not contain magic keywords like "$user"
1006          * Needs transaction
1007          *
1008          * @see getSearchPath()
1009          * @see setSearchPath()
1010          * @since 1.19
1011          * @return array List of actual schemas for the current sesson
1012          */
1013         public function getSchemas() {
1014                 $res = $this->query(
1015                         "SELECT current_schemas(false)",
1016                         __METHOD__,
1017                         self::QUERY_IGNORE_DBO_TRX
1018                 );
1019                 $row = $this->fetchRow( $res );
1020                 $schemas = [];
1021
1022                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1023
1024                 return $this->pg_array_parse( $row[0], $schemas );
1025         }
1026
1027         /**
1028          * Return search patch for schemas
1029          * This is different from getSchemas() since it contain magic keywords
1030          * (like "$user").
1031          * Needs transaction
1032          *
1033          * @since 1.19
1034          * @return array How to search for table names schemas for the current user
1035          */
1036         public function getSearchPath() {
1037                 $res = $this->query( "SHOW search_path", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
1038                 $row = $this->fetchRow( $res );
1039
1040                 /* PostgreSQL returns SHOW values as strings */
1041
1042                 return explode( ",", $row[0] );
1043         }
1044
1045         /**
1046          * Update search_path, values should already be sanitized
1047          * Values may contain magic keywords like "$user"
1048          * @since 1.19
1049          *
1050          * @param array $search_path List of schemas to be searched by default
1051          */
1052         private function setSearchPath( $search_path ) {
1053                 $this->query(
1054                         "SET search_path = " . implode( ", ", $search_path ),
1055                         __METHOD__,
1056                         self::QUERY_IGNORE_DBO_TRX
1057                 );
1058         }
1059
1060         /**
1061          * Determine default schema for the current application
1062          * Adjust this session schema search path if desired schema exists
1063          * and is not alread there.
1064          *
1065          * We need to have name of the core schema stored to be able
1066          * to query database metadata.
1067          *
1068          * This will be also called by the installer after the schema is created
1069          *
1070          * @since 1.19
1071          *
1072          * @param string $desiredSchema
1073          */
1074         public function determineCoreSchema( $desiredSchema ) {
1075                 if ( $this->trxLevel() ) {
1076                         // We do not want the schema selection to change on ROLLBACK or INSERT SELECT.
1077                         // See https://www.postgresql.org/docs/8.3/sql-set.html
1078                         throw new DBUnexpectedError(
1079                                 $this,
1080                                 __METHOD__ . ": a transaction is currently active."
1081                         );
1082                 }
1083
1084                 if ( $this->schemaExists( $desiredSchema ) ) {
1085                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1086                                 $this->coreSchema = $desiredSchema;
1087                                 $this->queryLogger->debug(
1088                                         "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1089                         } else {
1090                                 /**
1091                                  * Prepend our schema (e.g. 'mediawiki') in front
1092                                  * of the search path
1093                                  * Fixes T17816
1094                                  */
1095                                 $search_path = $this->getSearchPath();
1096                                 array_unshift( $search_path, $this->addIdentifierQuotes( $desiredSchema ) );
1097                                 $this->setSearchPath( $search_path );
1098                                 $this->coreSchema = $desiredSchema;
1099                                 $this->queryLogger->debug(
1100                                         "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1101                         }
1102                 } else {
1103                         $this->coreSchema = $this->getCurrentSchema();
1104                         $this->queryLogger->debug(
1105                                 "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1106                                 $this->coreSchema . "\"\n" );
1107                 }
1108         }
1109
1110         /**
1111          * Return schema name for core application tables
1112          *
1113          * @since 1.19
1114          * @return string Core schema name
1115          */
1116         public function getCoreSchema() {
1117                 return $this->coreSchema;
1118         }
1119
1120         /**
1121          * Return schema names for temporary tables and core application tables
1122          *
1123          * @since 1.31
1124          * @return string[] schema names
1125          */
1126         public function getCoreSchemas() {
1127                 if ( $this->tempSchema ) {
1128                         return [ $this->tempSchema, $this->getCoreSchema() ];
1129                 }
1130
1131                 $res = $this->query(
1132                         "SELECT nspname FROM pg_catalog.pg_namespace n WHERE n.oid = pg_my_temp_schema()", __METHOD__
1133                 );
1134                 $row = $this->fetchObject( $res );
1135                 if ( $row ) {
1136                         $this->tempSchema = $row->nspname;
1137                         return [ $this->tempSchema, $this->getCoreSchema() ];
1138                 }
1139
1140                 return [ $this->getCoreSchema() ];
1141         }
1142
1143         public function getServerVersion() {
1144                 if ( !isset( $this->numericVersion ) ) {
1145                         $conn = $this->getBindingHandle();
1146                         $versionInfo = pg_version( $conn );
1147                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1148                                 // Old client, abort install
1149                                 $this->numericVersion = '7.3 or earlier';
1150                         } elseif ( isset( $versionInfo['server'] ) ) {
1151                                 // Normal client
1152                                 $this->numericVersion = $versionInfo['server'];
1153                         } else {
1154                                 // T18937: broken pgsql extension from PHP<5.3
1155                                 $this->numericVersion = pg_parameter_status( $conn, 'server_version' );
1156                         }
1157                 }
1158
1159                 return $this->numericVersion;
1160         }
1161
1162         /**
1163          * Query whether a given relation exists (in the given schema, or the
1164          * default mw one if not given)
1165          * @param string $table
1166          * @param array|string $types
1167          * @param bool|string $schema
1168          * @return bool
1169          */
1170         private function relationExists( $table, $types, $schema = false ) {
1171                 if ( !is_array( $types ) ) {
1172                         $types = [ $types ];
1173                 }
1174                 if ( $schema === false ) {
1175                         $schemas = $this->getCoreSchemas();
1176                 } else {
1177                         $schemas = [ $schema ];
1178                 }
1179                 $table = $this->realTableName( $table, 'raw' );
1180                 $etable = $this->addQuotes( $table );
1181                 foreach ( $schemas as $schema ) {
1182                         $eschema = $this->addQuotes( $schema );
1183                         $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1184                                 . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1185                                 . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1186                         $res = $this->query( $sql );
1187                         if ( $res && $res->numRows() ) {
1188                                 return true;
1189                         }
1190                 }
1191
1192                 return false;
1193         }
1194
1195         /**
1196          * For backward compatibility, this function checks both tables and views.
1197          * @param string $table
1198          * @param string $fname
1199          * @param bool|string $schema
1200          * @return bool
1201          */
1202         public function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1203                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1204         }
1205
1206         public function sequenceExists( $sequence, $schema = false ) {
1207                 return $this->relationExists( $sequence, 'S', $schema );
1208         }
1209
1210         public function triggerExists( $table, $trigger ) {
1211                 $q = <<<SQL
1212         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1213                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1214                         AND tgrelid=pg_class.oid
1215                         AND nspname=%s AND relname=%s AND tgname=%s
1216 SQL;
1217                 foreach ( $this->getCoreSchemas() as $schema ) {
1218                         $res = $this->query(
1219                                 sprintf(
1220                                         $q,
1221                                         $this->addQuotes( $schema ),
1222                                         $this->addQuotes( $table ),
1223                                         $this->addQuotes( $trigger )
1224                                 )
1225                         );
1226                         if ( $res && $res->numRows() ) {
1227                                 return true;
1228                         }
1229                 }
1230
1231                 return false;
1232         }
1233
1234         public function ruleExists( $table, $rule ) {
1235                 $exists = $this->selectField( 'pg_rules', 'rulename',
1236                         [
1237                                 'rulename' => $rule,
1238                                 'tablename' => $table,
1239                                 'schemaname' => $this->getCoreSchemas()
1240                         ]
1241                 );
1242
1243                 return $exists === $rule;
1244         }
1245
1246         public function constraintExists( $table, $constraint ) {
1247                 foreach ( $this->getCoreSchemas() as $schema ) {
1248                         $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1249                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1250                                 $this->addQuotes( $schema ),
1251                                 $this->addQuotes( $table ),
1252                                 $this->addQuotes( $constraint )
1253                         );
1254                         $res = $this->query( $sql );
1255                         if ( $res && $res->numRows() ) {
1256                                 return true;
1257                         }
1258                 }
1259                 return false;
1260         }
1261
1262         /**
1263          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1264          * @param string $schema
1265          * @return bool
1266          */
1267         public function schemaExists( $schema ) {
1268                 if ( !strlen( $schema ) ) {
1269                         return false; // short-circuit
1270                 }
1271
1272                 $res = $this->query(
1273                         "SELECT 1 FROM pg_catalog.pg_namespace " .
1274                         "WHERE nspname = " . $this->addQuotes( $schema ) . " LIMIT 1",
1275                         __METHOD__,
1276                         self::QUERY_IGNORE_DBO_TRX
1277                 );
1278
1279                 return ( $this->numRows( $res ) > 0 );
1280         }
1281
1282         /**
1283          * Returns true if a given role (i.e. user) exists, false otherwise.
1284          * @param string $roleName
1285          * @return bool
1286          */
1287         public function roleExists( $roleName ) {
1288                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1289                         [ 'rolname' => $roleName ], __METHOD__ );
1290
1291                 return (bool)$exists;
1292         }
1293
1294         /**
1295          * @param string $table
1296          * @param string $field
1297          * @return PostgresField|null
1298          */
1299         public function fieldInfo( $table, $field ) {
1300                 return PostgresField::fromText( $this, $table, $field );
1301         }
1302
1303         /**
1304          * pg_field_type() wrapper
1305          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1306          * @param int $index Field number, starting from 0
1307          * @return string
1308          */
1309         public function fieldType( $res, $index ) {
1310                 if ( $res instanceof ResultWrapper ) {
1311                         $res = $res->result;
1312                 }
1313
1314                 return pg_field_type( $res, $index );
1315         }
1316
1317         public function encodeBlob( $b ) {
1318                 return new PostgresBlob( pg_escape_bytea( $b ) );
1319         }
1320
1321         public function decodeBlob( $b ) {
1322                 if ( $b instanceof PostgresBlob ) {
1323                         $b = $b->fetch();
1324                 } elseif ( $b instanceof Blob ) {
1325                         return $b->fetch();
1326                 }
1327
1328                 return pg_unescape_bytea( $b );
1329         }
1330
1331         public function strencode( $s ) {
1332                 // Should not be called by us
1333                 return pg_escape_string( $this->getBindingHandle(), (string)$s );
1334         }
1335
1336         public function addQuotes( $s ) {
1337                 $conn = $this->getBindingHandle();
1338
1339                 if ( is_null( $s ) ) {
1340                         return 'NULL';
1341                 } elseif ( is_bool( $s ) ) {
1342                         return intval( $s );
1343                 } elseif ( $s instanceof Blob ) {
1344                         if ( $s instanceof PostgresBlob ) {
1345                                 $s = $s->fetch();
1346                         } else {
1347                                 $s = pg_escape_bytea( $conn, $s->fetch() );
1348                         }
1349                         return "'$s'";
1350                 } elseif ( $s instanceof NextSequenceValue ) {
1351                         return 'DEFAULT';
1352                 }
1353
1354                 return "'" . pg_escape_string( $conn, (string)$s ) . "'";
1355         }
1356
1357         public function makeSelectOptions( $options ) {
1358                 $preLimitTail = $postLimitTail = '';
1359                 $startOpts = $useIndex = $ignoreIndex = '';
1360
1361                 $noKeyOptions = [];
1362                 foreach ( $options as $key => $option ) {
1363                         if ( is_numeric( $key ) ) {
1364                                 $noKeyOptions[$option] = true;
1365                         }
1366                 }
1367
1368                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1369
1370                 $preLimitTail .= $this->makeOrderBy( $options );
1371
1372                 if ( isset( $options['FOR UPDATE'] ) ) {
1373                         $postLimitTail .= ' FOR UPDATE OF ' .
1374                                 implode( ', ', array_map( [ $this, 'tableName' ], $options['FOR UPDATE'] ) );
1375                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1376                         $postLimitTail .= ' FOR UPDATE';
1377                 }
1378
1379                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1380                         $startOpts .= 'DISTINCT';
1381                 }
1382
1383                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1384         }
1385
1386         public function buildConcat( $stringList ) {
1387                 return implode( ' || ', $stringList );
1388         }
1389
1390         public function buildGroupConcatField(
1391                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1392         ) {
1393                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1394
1395                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1396         }
1397
1398         public function buildStringCast( $field ) {
1399                 return $field . '::text';
1400         }
1401
1402         public function streamStatementEnd( &$sql, &$newLine ) {
1403                 # Allow dollar quoting for function declarations
1404                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1405                         if ( $this->delimiter ) {
1406                                 $this->delimiter = false;
1407                         } else {
1408                                 $this->delimiter = ';';
1409                         }
1410                 }
1411
1412                 return parent::streamStatementEnd( $sql, $newLine );
1413         }
1414
1415         public function doLockTables( array $read, array $write, $method ) {
1416                 $tablesWrite = [];
1417                 foreach ( $write as $table ) {
1418                         $tablesWrite[] = $this->tableName( $table );
1419                 }
1420                 $tablesRead = [];
1421                 foreach ( $read as $table ) {
1422                         $tablesRead[] = $this->tableName( $table );
1423                 }
1424
1425                 // Acquire locks for the duration of the current transaction...
1426                 if ( $tablesWrite ) {
1427                         $this->query(
1428                                 'LOCK TABLE ONLY ' . implode( ',', $tablesWrite ) . ' IN EXCLUSIVE MODE',
1429                                 $method
1430                         );
1431                 }
1432                 if ( $tablesRead ) {
1433                         $this->query(
1434                                 'LOCK TABLE ONLY ' . implode( ',', $tablesRead ) . ' IN SHARE MODE',
1435                                 $method
1436                         );
1437                 }
1438
1439                 return true;
1440         }
1441
1442         public function lockIsFree( $lockName, $method ) {
1443                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1444                         return false; // already held
1445                 }
1446                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1447                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1448                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1449                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1450                 $row = $this->fetchObject( $result );
1451
1452                 return ( $row->lockstatus === 't' );
1453         }
1454
1455         public function lock( $lockName, $method, $timeout = 5 ) {
1456                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1457                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1458                 $loop = new WaitConditionLoop(
1459                         function () use ( $lockName, $key, $timeout, $method ) {
1460                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1461                                 $row = $this->fetchObject( $res );
1462                                 if ( $row->lockstatus === 't' ) {
1463                                         parent::lock( $lockName, $method, $timeout ); // record
1464                                         return true;
1465                                 }
1466
1467                                 return WaitConditionLoop::CONDITION_CONTINUE;
1468                         },
1469                         $timeout
1470                 );
1471
1472                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1473         }
1474
1475         public function unlock( $lockName, $method ) {
1476                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1477                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1478                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1479                 $row = $this->fetchObject( $result );
1480
1481                 if ( $row->lockstatus === 't' ) {
1482                         parent::unlock( $lockName, $method ); // record
1483                         return true;
1484                 }
1485
1486                 $this->queryLogger->debug( __METHOD__ . " failed to release lock\n" );
1487
1488                 return false;
1489         }
1490
1491         public function serverIsReadOnly() {
1492                 $res = $this->query( "SHOW default_transaction_read_only", __METHOD__ );
1493                 $row = $this->fetchObject( $res );
1494
1495                 return $row ? ( strtolower( $row->default_transaction_read_only ) === 'on' ) : false;
1496         }
1497
1498         public static function getAttributes() {
1499                 return [ self::ATTR_SCHEMAS_AS_TABLE_GROUPS => true ];
1500         }
1501
1502         /**
1503          * @param string $lockName
1504          * @return string Integer
1505          */
1506         private function bigintFromLockName( $lockName ) {
1507                 return \Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1508         }
1509 }
1510
1511 /**
1512  * @deprecated since 1.29
1513  */
1514 class_alias( DatabasePostgres::class, 'DatabasePostgres' );