includes/libs/rdbms/database/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23 namespace Wikimedia\Rdbms;
  24
  25 use Wikimedia\Timestamp\ConvertibleTimestamp;
  26 use Wikimedia\WaitConditionLoop;
  27 use Wikimedia\AtEase\AtEase;
  28 use Exception;
  29
  30 /**
  31  * @ingroup Database
  32  */
  33 class DatabasePostgres extends Database {
  34         /** @var int|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 implicitOrderby() {
  68                 return false;
  69         }
  70
  71         public function hasConstraint( $name ) {
  72                 foreach ( $this->getCoreSchemas() as $schema ) {
  73                         $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
  74                                 "WHERE c.connamespace = n.oid AND conname = " .
  75                                 $this->addQuotes( $name ) . " AND n.nspname = " .
  76                                 $this->addQuotes( $schema );
  77                         $res = $this->doQuery( $sql );
  78                         if ( $res && $this->numRows( $res ) ) {
  79                                 return true;
  80                         }
  81                 }
  82                 return false;
  83         }
  84
  85         protected function open( $server, $user, $password, $dbName, $schema, $tablePrefix ) {
  86                 // Test for Postgres support, to avoid suppressed fatal error
  87                 if ( !function_exists( 'pg_connect' ) ) {
  88                         throw new DBConnectionError(
  89                                 $this,
  90                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
  91                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
  92                                 "webserver and database)\n"
  93                         );
  94                 }
  95
  96                 $this->close();
  97
  98                 $this->server = $server;
  99                 $this->user = $user;
 100                 $this->password = $password;
 101
 102                 $connectVars = [
 103                         // pg_connect() user $user as the default database. Since a database is *required*,
 104                         // at least pick a "don't care" database that is more likely to exist. This case
 105                         // arrises when LoadBalancer::getConnection( $i, [], '' ) is used.
 106                         'dbname' => strlen( $dbName ) ? $dbName : 'postgres',
 107                         'user' => $user,
 108                         'password' => $password
 109                 ];
 110                 if ( $server != false && $server != '' ) {
 111                         $connectVars['host'] = $server;
 112                 }
 113                 if ( (int)$this->port > 0 ) {
 114                         $connectVars['port'] = (int)$this->port;
 115                 }
 116                 if ( $this->flags & self::DBO_SSL ) {
 117                         $connectVars['sslmode'] = 'require';
 118                 }
 119
 120                 $this->connectString = $this->makeConnectionString( $connectVars );
 121
 122                 $this->installErrorHandler();
 123                 try {
 124                         // Use new connections to let LoadBalancer/LBFactory handle reuse
 125                         $this->conn = pg_connect( $this->connectString, PGSQL_CONNECT_FORCE_NEW );
 126                 } catch ( Exception $ex ) {
 127                         $this->restoreErrorHandler();
 128                         throw $ex;
 129                 }
 130                 $phpError = $this->restoreErrorHandler();
 131
 132                 if ( !$this->conn ) {
 133                         $this->queryLogger->debug(
 134                                 "DB connection error\n" .
 135                                 "Server: $server, Database: $dbName, User: $user, Password: " .
 136                                 substr( $password, 0, 3 ) . "...\n"
 137                         );
 138                         $this->queryLogger->debug( $this->lastError() . "\n" );
 139                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 140                 }
 141
 142                 try {
 143                         // If called from the command-line (e.g. importDump), only show errors.
 144                         // No transaction should be open at this point, so the problem of the SET
 145                         // effects being rolled back should not be an issue.
 146                         // See https://www.postgresql.org/docs/8.3/sql-set.html
 147                         $variables = [];
 148                         if ( $this->cliMode ) {
 149                                 $variables['client_min_messages'] = 'ERROR';
 150                         }
 151                         $variables += [
 152                                 'client_encoding' => 'UTF8',
 153                                 'datestyle' => 'ISO, YMD',
 154                                 'timezone' => 'GMT',
 155                                 'standard_conforming_strings' => 'on',
 156                                 'bytea_output' => 'escape'
 157                         ];
 158                         foreach ( $variables as $var => $val ) {
 159                                 $this->query(
 160                                         'SET ' . $this->addIdentifierQuotes( $var ) . ' = ' . $this->addQuotes( $val ),
 161                                         __METHOD__,
 162                                         self::QUERY_IGNORE_DBO_TRX | self::QUERY_NO_RETRY
 163                                 );
 164                         }
 165
 166                         $this->determineCoreSchema( $schema );
 167                         $this->currentDomain = new DatabaseDomain( $dbName, $schema, $tablePrefix );
 168                 } catch ( Exception $e ) {
 169                         // Connection was not fully initialized and is not safe for use
 170                         $this->conn = false;
 171                 }
 172         }
 173
 174         protected function relationSchemaQualifier() {
 175                 if ( $this->coreSchema === $this->currentDomain->getSchema() ) {
 176                         // The schema to be used is now in the search path; no need for explicit qualification
 177                         return '';
 178                 }
 179
 180                 return parent::relationSchemaQualifier();
 181         }
 182
 183         public function databasesAreIndependent() {
 184                 return true;
 185         }
 186
 187         public function doSelectDomain( DatabaseDomain $domain ) {
 188                 if ( $this->getDBname() !== $domain->getDatabase() ) {
 189                         // Postgres doesn't support selectDB in the same way MySQL does.
 190                         // So if the DB name doesn't match the open connection, open a new one
 191                         $this->open(
 192                                 $this->server,
 193                                 $this->user,
 194                                 $this->password,
 195                                 $domain->getDatabase(),
 196                                 $domain->getSchema(),
 197                                 $domain->getTablePrefix()
 198                         );
 199                 } else {
 200                         $this->currentDomain = $domain;
 201                 }
 202
 203                 return true;
 204         }
 205
 206         /**
 207          * @param string[] $vars
 208          * @return string
 209          */
 210         private function makeConnectionString( $vars ) {
 211                 $s = '';
 212                 foreach ( $vars as $name => $value ) {
 213                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 214                 }
 215
 216                 return $s;
 217         }
 218
 219         protected function closeConnection() {
 220                 return $this->conn ? pg_close( $this->conn ) : true;
 221         }
 222
 223         protected function isTransactableQuery( $sql ) {
 224                 return parent::isTransactableQuery( $sql ) &&
 225                         !preg_match( '/^SELECT\s+pg_(try_|)advisory_\w+\(/', $sql );
 226         }
 227
 228         /**
 229          * @param string $sql
 230          * @return bool|mixed|resource
 231          */
 232         public function doQuery( $sql ) {
 233                 $conn = $this->getBindingHandle();
 234
 235                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 236                 // Clear previously left over PQresult
 237                 while ( $res = pg_get_result( $conn ) ) {
 238                         pg_free_result( $res );
 239                 }
 240                 if ( pg_send_query( $conn, $sql ) === false ) {
 241                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 242                 }
 243                 $this->lastResultHandle = pg_get_result( $conn );
 244                 if ( pg_result_error( $this->lastResultHandle ) ) {
 245                         return false;
 246                 }
 247
 248                 return $this->lastResultHandle;
 249         }
 250
 251         protected function dumpError() {
 252                 $diags = [
 253                         PGSQL_DIAG_SEVERITY,
 254                         PGSQL_DIAG_SQLSTATE,
 255                         PGSQL_DIAG_MESSAGE_PRIMARY,
 256                         PGSQL_DIAG_MESSAGE_DETAIL,
 257                         PGSQL_DIAG_MESSAGE_HINT,
 258                         PGSQL_DIAG_STATEMENT_POSITION,
 259                         PGSQL_DIAG_INTERNAL_POSITION,
 260                         PGSQL_DIAG_INTERNAL_QUERY,
 261                         PGSQL_DIAG_CONTEXT,
 262                         PGSQL_DIAG_SOURCE_FILE,
 263                         PGSQL_DIAG_SOURCE_LINE,
 264                         PGSQL_DIAG_SOURCE_FUNCTION
 265                 ];
 266                 foreach ( $diags as $d ) {
 267                         $this->queryLogger->debug( sprintf( "PgSQL ERROR(%d): %s\n",
 268                                 $d, pg_result_error_field( $this->lastResultHandle, $d ) ) );
 269                 }
 270         }
 271
 272         public function freeResult( $res ) {
 273                 AtEase::suppressWarnings();
 274                 $ok = pg_free_result( ResultWrapper::unwrap( $res ) );
 275                 AtEase::restoreWarnings();
 276                 if ( !$ok ) {
 277                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 278                 }
 279         }
 280
 281         public function fetchObject( $res ) {
 282                 AtEase::suppressWarnings();
 283                 $row = pg_fetch_object( ResultWrapper::unwrap( $res ) );
 284                 AtEase::restoreWarnings();
 285                 # @todo FIXME: HACK HACK HACK HACK debug
 286
 287                 # @todo hashar: not sure if the following test really trigger if the object
 288                 #          fetching failed.
 289                 $conn = $this->getBindingHandle();
 290                 if ( pg_last_error( $conn ) ) {
 291                         throw new DBUnexpectedError(
 292                                 $this,
 293                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 294                         );
 295                 }
 296
 297                 return $row;
 298         }
 299
 300         public function fetchRow( $res ) {
 301                 AtEase::suppressWarnings();
 302                 $row = pg_fetch_array( ResultWrapper::unwrap( $res ) );
 303                 AtEase::restoreWarnings();
 304
 305                 $conn = $this->getBindingHandle();
 306                 if ( pg_last_error( $conn ) ) {
 307                         throw new DBUnexpectedError(
 308                                 $this,
 309                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 310                         );
 311                 }
 312
 313                 return $row;
 314         }
 315
 316         public function numRows( $res ) {
 317                 if ( $res === false ) {
 318                         return 0;
 319                 }
 320
 321                 AtEase::suppressWarnings();
 322                 $n = pg_num_rows( ResultWrapper::unwrap( $res ) );
 323                 AtEase::restoreWarnings();
 324
 325                 $conn = $this->getBindingHandle();
 326                 if ( pg_last_error( $conn ) ) {
 327                         throw new DBUnexpectedError(
 328                                 $this,
 329                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 330                         );
 331                 }
 332
 333                 return $n;
 334         }
 335
 336         public function numFields( $res ) {
 337                 return pg_num_fields( ResultWrapper::unwrap( $res ) );
 338         }
 339
 340         public function fieldName( $res, $n ) {
 341                 return pg_field_name( ResultWrapper::unwrap( $res ), $n );
 342         }
 343
 344         public function insertId() {
 345                 $res = $this->query( "SELECT lastval()" );
 346                 $row = $this->fetchRow( $res );
 347                 return is_null( $row[0] ) ? null : (int)$row[0];
 348         }
 349
 350         public function dataSeek( $res, $row ) {
 351                 return pg_result_seek( ResultWrapper::unwrap( $res ), $row );
 352         }
 353
 354         public function lastError() {
 355                 if ( $this->conn ) {
 356                         if ( $this->lastResultHandle ) {
 357                                 return pg_result_error( $this->lastResultHandle );
 358                         } else {
 359                                 return pg_last_error();
 360                         }
 361                 }
 362
 363                 return $this->getLastPHPError() ?: 'No database connection';
 364         }
 365
 366         public function lastErrno() {
 367                 if ( $this->lastResultHandle ) {
 368                         return pg_result_error_field( $this->lastResultHandle, PGSQL_DIAG_SQLSTATE );
 369                 } else {
 370                         return false;
 371                 }
 372         }
 373
 374         protected function fetchAffectedRowCount() {
 375                 if ( !$this->lastResultHandle ) {
 376                         return 0;
 377                 }
 378
 379                 return pg_affected_rows( $this->lastResultHandle );
 380         }
 381
 382         /**
 383          * Estimate rows in dataset
 384          * Returns estimated count, based on EXPLAIN output
 385          * This is not necessarily an accurate estimate, so use sparingly
 386          * Returns -1 if count cannot be found
 387          * Takes same arguments as Database::select()
 388          *
 389          * @param string $table
 390          * @param string $var
 391          * @param string $conds
 392          * @param string $fname
 393          * @param array $options
 394          * @param array $join_conds
 395          * @return int
 396          */
 397         public function estimateRowCount( $table, $var = '*', $conds = '',
 398                 $fname = __METHOD__, $options = [], $join_conds = []
 399         ) {
 400                 $conds = $this->normalizeConditions( $conds, $fname );
 401                 $column = $this->extractSingleFieldFromList( $var );
 402                 if ( is_string( $column ) && !in_array( $column, [ '*', '1' ] ) ) {
 403                         $conds[] = "$column IS NOT NULL";
 404                 }
 405
 406                 $options['EXPLAIN'] = true;
 407                 $res = $this->select( $table, $var, $conds, $fname, $options, $join_conds );
 408                 $rows = -1;
 409                 if ( $res ) {
 410                         $row = $this->fetchRow( $res );
 411                         $count = [];
 412                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 413                                 $rows = (int)$count[1];
 414                         }
 415                 }
 416
 417                 return $rows;
 418         }
 419
 420         public function indexInfo( $table, $index, $fname = __METHOD__ ) {
 421                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 422                 $res = $this->query( $sql, $fname );
 423                 if ( !$res ) {
 424                         return null;
 425                 }
 426                 foreach ( $res as $row ) {
 427                         if ( $row->indexname == $this->indexName( $index ) ) {
 428                                 return $row;
 429                         }
 430                 }
 431
 432                 return false;
 433         }
 434
 435         public function indexAttributes( $index, $schema = false ) {
 436                 if ( $schema === false ) {
 437                         $schemas = $this->getCoreSchemas();
 438                 } else {
 439                         $schemas = [ $schema ];
 440                 }
 441
 442                 $eindex = $this->addQuotes( $index );
 443
 444                 foreach ( $schemas as $schema ) {
 445                         $eschema = $this->addQuotes( $schema );
 446                         /*
 447                          * A subquery would be not needed if we didn't care about the order
 448                          * of attributes, but we do
 449                          */
 450                         $sql = <<<__INDEXATTR__
 451
 452                                 SELECT opcname,
 453                                         attname,
 454                                         i.indoption[s.g] as option,
 455                                         pg_am.amname
 456                                 FROM
 457                                         (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 458                                                 FROM
 459                                                         pg_index isub
 460                                                 JOIN pg_class cis
 461                                                         ON cis.oid=isub.indexrelid
 462                                                 JOIN pg_namespace ns
 463                                                         ON cis.relnamespace = ns.oid
 464                                                 WHERE cis.relname=$eindex AND ns.nspname=$eschema) AS s,
 465                                         pg_attribute,
 466                                         pg_opclass opcls,
 467                                         pg_am,
 468                                         pg_class ci
 469                                         JOIN pg_index i
 470                                                 ON ci.oid=i.indexrelid
 471                                         JOIN pg_class ct
 472                                                 ON ct.oid = i.indrelid
 473                                         JOIN pg_namespace n
 474                                                 ON ci.relnamespace = n.oid
 475                                         WHERE
 476                                                 ci.relname=$eindex AND n.nspname=$eschema
 477                                                 AND     attrelid = ct.oid
 478                                                 AND     i.indkey[s.g] = attnum
 479                                                 AND     i.indclass[s.g] = opcls.oid
 480                                                 AND     pg_am.oid = opcls.opcmethod
 481 __INDEXATTR__;
 482                         $res = $this->query( $sql, __METHOD__ );
 483                         $a = [];
 484                         if ( $res ) {
 485                                 foreach ( $res as $row ) {
 486                                         $a[] = [
 487                                                 $row->attname,
 488                                                 $row->opcname,
 489                                                 $row->amname,
 490                                                 $row->option ];
 491                                 }
 492                                 return $a;
 493                         }
 494                 }
 495                 return null;
 496         }
 497
 498         public function indexUnique( $table, $index, $fname = __METHOD__ ) {
 499                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 500                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 501                         $this->strencode( $this->indexName( $index ) ) .
 502                         ")'";
 503                 $res = $this->query( $sql, $fname );
 504                 if ( !$res ) {
 505                         return null;
 506                 }
 507
 508                 return $res->numRows() > 0;
 509         }
 510
 511         public function selectSQLText(
 512                 $table, $vars, $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
 513         ) {
 514                 if ( is_string( $options ) ) {
 515                         $options = [ $options ];
 516                 }
 517
 518                 // Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 519                 // to the parent function to get the actual SQL text.
 520                 // In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 521                 // can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to
 522                 // do so causes a DB error. This wrapper checks which tables can be locked and adjusts it
 523                 // accordingly.
 524                 // MySQL uses "ORDER BY NULL" as an optimization hint, but that is illegal in PostgreSQL.
 525                 if ( is_array( $options ) ) {
 526                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 527                         if ( $forUpdateKey !== false && $join_conds ) {
 528                                 unset( $options[$forUpdateKey] );
 529                                 $options['FOR UPDATE'] = [];
 530
 531                                 $toCheck = $table;
 532                                 reset( $toCheck );
 533                                 while ( $toCheck ) {
 534                                         $alias = key( $toCheck );
 535                                         $name = $toCheck[$alias];
 536                                         unset( $toCheck[$alias] );
 537
 538                                         $hasAlias = !is_numeric( $alias );
 539                                         if ( !$hasAlias && is_string( $name ) ) {
 540                                                 $alias = $name;
 541                                         }
 542
 543                                         if ( !isset( $join_conds[$alias] ) ||
 544                                                 !preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_conds[$alias][0] )
 545                                         ) {
 546                                                 if ( is_array( $name ) ) {
 547                                                         // It's a parenthesized group, process all the tables inside the group.
 548                                                         $toCheck = array_merge( $toCheck, $name );
 549                                                 } else {
 550                                                         // Quote alias names so $this->tableName() won't mangle them
 551                                                         $options['FOR UPDATE'][] = $hasAlias ? $this->addIdentifierQuotes( $alias ) : $alias;
 552                                                 }
 553                                         }
 554                                 }
 555                         }
 556
 557                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 558                                 unset( $options['ORDER BY'] );
 559                         }
 560                 }
 561
 562                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 563         }
 564
 565         /** @inheritDoc */
 566         public function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 567                 if ( !count( $args ) ) {
 568                         return true;
 569                 }
 570
 571                 $table = $this->tableName( $table );
 572                 if ( !isset( $this->numericVersion ) ) {
 573                         $this->getServerVersion();
 574                 }
 575
 576                 if ( !is_array( $options ) ) {
 577                         $options = [ $options ];
 578                 }
 579
 580                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 581                         $rows = $args;
 582                         $keys = array_keys( $args[0] );
 583                 } else {
 584                         $rows = [ $args ];
 585                         $keys = array_keys( $args );
 586                 }
 587
 588                 $ignore = in_array( 'IGNORE', $options );
 589
 590                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 591
 592                 if ( $this->numericVersion >= 9.5 || !$ignore ) {
 593                         // No IGNORE or our PG has "ON CONFLICT DO NOTHING"
 594                         $first = true;
 595                         foreach ( $rows as $row ) {
 596                                 if ( $first ) {
 597                                         $first = false;
 598                                 } else {
 599                                         $sql .= ',';
 600                                 }
 601                                 $sql .= '(' . $this->makeList( $row ) . ')';
 602                         }
 603                         if ( $ignore ) {
 604                                 $sql .= ' ON CONFLICT DO NOTHING';
 605                         }
 606                         $this->query( $sql, $fname );
 607                 } else {
 608                         // Emulate IGNORE by doing each row individually, with savepoints
 609                         // to roll back as necessary.
 610                         $numrowsinserted = 0;
 611
 612                         $tok = $this->startAtomic( "$fname (outer)", self::ATOMIC_CANCELABLE );
 613                         try {
 614                                 foreach ( $rows as $row ) {
 615                                         $tempsql = $sql;
 616                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 617
 618                                         $this->startAtomic( "$fname (inner)", self::ATOMIC_CANCELABLE );
 619                                         try {
 620                                                 $this->query( $tempsql, $fname );
 621                                                 $this->endAtomic( "$fname (inner)" );
 622                                                 $numrowsinserted++;
 623                                         } catch ( DBQueryError $e ) {
 624                                                 $this->cancelAtomic( "$fname (inner)" );
 625                                                 // Our IGNORE is supposed to ignore duplicate key errors, but not others.
 626                                                 // (even though MySQL's version apparently ignores all errors)
 627                                                 if ( $e->errno !== '23505' ) {
 628                                                         throw $e;
 629                                                 }
 630                                         }
 631                                 }
 632                         } catch ( Exception $e ) {
 633                                 $this->cancelAtomic( "$fname (outer)", $tok );
 634                                 throw $e;
 635                         }
 636                         $this->endAtomic( "$fname (outer)" );
 637
 638                         // Set the affected row count for the whole operation
 639                         $this->affectedRowCount = $numrowsinserted;
 640                 }
 641
 642                 return true;
 643         }
 644
 645         protected function makeUpdateOptionsArray( $options ) {
 646                 if ( !is_array( $options ) ) {
 647                         $options = [ $options ];
 648                 }
 649
 650                 // PostgreSQL doesn't support anything like "ignore" for
 651                 // UPDATE.
 652                 $options = array_diff( $options, [ 'IGNORE' ] );
 653
 654                 return parent::makeUpdateOptionsArray( $options );
 655         }
 656
 657         /**
 658          * INSERT SELECT wrapper
 659          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 660          * Source items may be literals rather then field names, but strings should
 661          * be quoted with Database::addQuotes()
 662          * $conds may be "*" to copy the whole table
 663          * srcTable may be an array of tables.
 664          * @todo FIXME: Implement this a little better (separate select/insert)?
 665          *
 666          * @param string $destTable
 667          * @param array|string $srcTable
 668          * @param array $varMap
 669          * @param array $conds
 670          * @param string $fname
 671          * @param array $insertOptions
 672          * @param array $selectOptions
 673          * @param array $selectJoinConds
 674          */
 675         protected function nativeInsertSelect(
 676                 $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 677                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 678         ) {
 679                 if ( !is_array( $insertOptions ) ) {
 680                         $insertOptions = [ $insertOptions ];
 681                 }
 682
 683                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 684                         if ( $this->getServerVersion() >= 9.5 ) {
 685                                 // Use ON CONFLICT DO NOTHING if we have it for IGNORE
 686                                 $destTable = $this->tableName( $destTable );
 687
 688                                 $selectSql = $this->selectSQLText(
 689                                         $srcTable,
 690                                         array_values( $varMap ),
 691                                         $conds,
 692                                         $fname,
 693                                         $selectOptions,
 694                                         $selectJoinConds
 695                                 );
 696
 697                                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ') ' .
 698                                         $selectSql . ' ON CONFLICT DO NOTHING';
 699
 700                                 $this->query( $sql, $fname );
 701                         } else {
 702                                 // IGNORE and we don't have ON CONFLICT DO NOTHING, so just use the non-native version
 703                                 $this->nonNativeInsertSelect(
 704                                         $destTable, $srcTable, $varMap, $conds, $fname,
 705                                         $insertOptions, $selectOptions, $selectJoinConds
 706                                 );
 707                         }
 708                 } else {
 709                         parent::nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname,
 710                                 $insertOptions, $selectOptions, $selectJoinConds );
 711                 }
 712         }
 713
 714         public function tableName( $name, $format = 'quoted' ) {
 715                 // Replace reserved words with better ones
 716                 $name = $this->remappedTableName( $name );
 717
 718                 return parent::tableName( $name, $format );
 719         }
 720
 721         /**
 722          * @param string $name
 723          * @return string Value of $name or remapped name if $name is a reserved keyword
 724          */
 725         public function remappedTableName( $name ) {
 726                 return $this->keywordTableMap[$name] ?? $name;
 727         }
 728
 729         /**
 730          * @param string $name
 731          * @param string $format
 732          * @return string Qualified and encoded (if requested) table name
 733          */
 734         public function realTableName( $name, $format = 'quoted' ) {
 735                 return parent::tableName( $name, $format );
 736         }
 737
 738         public function nextSequenceValue( $seqName ) {
 739                 return new NextSequenceValue;
 740         }
 741
 742         /**
 743          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 744          *
 745          * @param string $seqName
 746          * @return int
 747          */
 748         public function currentSequenceValue( $seqName ) {
 749                 $safeseq = str_replace( "'", "''", $seqName );
 750                 $res = $this->query( "SELECT currval('$safeseq')" );
 751                 $row = $this->fetchRow( $res );
 752                 $currval = $row[0];
 753
 754                 return $currval;
 755         }
 756
 757         public function textFieldSize( $table, $field ) {
 758                 $table = $this->tableName( $table );
 759                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 760                         FROM pg_class c, pg_attribute a, pg_type t
 761                         WHERE relname='$table' AND a.attrelid=c.oid AND
 762                                 a.atttypid=t.oid and a.attname='$field'";
 763                 $res = $this->query( $sql );
 764                 $row = $this->fetchObject( $res );
 765                 if ( $row->ftype == 'varchar' ) {
 766                         $size = $row->size - 4;
 767                 } else {
 768                         $size = $row->size;
 769                 }
 770
 771                 return $size;
 772         }
 773
 774         public function limitResult( $sql, $limit, $offset = false ) {
 775                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 776         }
 777
 778         public function wasDeadlock() {
 779                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 780                 return $this->lastErrno() === '40P01';
 781         }
 782
 783         public function wasLockTimeout() {
 784                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 785                 return $this->lastErrno() === '55P03';
 786         }
 787
 788         public function wasConnectionError( $errno ) {
 789                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 790                 static $codes = [ '08000', '08003', '08006', '08001', '08004', '57P01', '57P03', '53300' ];
 791
 792                 return in_array( $errno, $codes, true );
 793         }
 794
 795         protected function wasKnownStatementRollbackError() {
 796                 return false; // transaction has to be rolled-back from error state
 797         }
 798
 799         public function duplicateTableStructure(
 800                 $oldName, $newName, $temporary = false, $fname = __METHOD__
 801         ) {
 802                 $newNameE = $this->addIdentifierQuotes( $newName );
 803                 $oldNameE = $this->addIdentifierQuotes( $oldName );
 804
 805                 $temporary = $temporary ? 'TEMPORARY' : '';
 806
 807                 $ret = $this->query(
 808                         "CREATE $temporary TABLE $newNameE " .
 809                                 "(LIKE $oldNameE INCLUDING DEFAULTS INCLUDING INDEXES)",
 810                         $fname,
 811                         $this::QUERY_PSEUDO_PERMANENT
 812                 );
 813                 if ( !$ret ) {
 814                         return $ret;
 815                 }
 816
 817                 $res = $this->query( 'SELECT attname FROM pg_class c'
 818                         . ' JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 819                         . ' JOIN pg_attribute a ON (a.attrelid = c.oid)'
 820                         . ' JOIN pg_attrdef d ON (c.oid=d.adrelid and a.attnum=d.adnum)'
 821                         . ' WHERE relkind = \'r\''
 822                         . ' AND nspname = ' . $this->addQuotes( $this->getCoreSchema() )
 823                         . ' AND relname = ' . $this->addQuotes( $oldName )
 824                         . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 825                         $fname
 826                 );
 827                 $row = $this->fetchObject( $res );
 828                 if ( $row ) {
 829                         $field = $row->attname;
 830                         $newSeq = "{$newName}_{$field}_seq";
 831                         $fieldE = $this->addIdentifierQuotes( $field );
 832                         $newSeqE = $this->addIdentifierQuotes( $newSeq );
 833                         $newSeqQ = $this->addQuotes( $newSeq );
 834                         $this->query(
 835                                 "CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE",
 836                                 $fname
 837                         );
 838                         $this->query(
 839                                 "ALTER TABLE $newNameE ALTER COLUMN $fieldE SET DEFAULT nextval({$newSeqQ}::regclass)",
 840                                 $fname
 841                         );
 842                 }
 843
 844                 return $ret;
 845         }
 846
 847         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
 848                 $table = $this->tableName( $table, 'raw' );
 849                 foreach ( $this->getCoreSchemas() as $schema ) {
 850                         $res = $this->query(
 851                                 'SELECT c.oid FROM pg_class c JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 852                                 . ' WHERE relkind = \'r\''
 853                                 . ' AND nspname = ' . $this->addQuotes( $schema )
 854                                 . ' AND relname = ' . $this->addQuotes( $table ),
 855                                 $fname
 856                         );
 857                         if ( !$res || !$this->numRows( $res ) ) {
 858                                 continue;
 859                         }
 860
 861                         $oid = $this->fetchObject( $res )->oid;
 862                         $res = $this->query( 'SELECT pg_get_expr(adbin, adrelid) AS adsrc FROM pg_attribute a'
 863                                 . ' JOIN pg_attrdef d ON (a.attrelid=d.adrelid and a.attnum=d.adnum)'
 864                                 . " WHERE a.attrelid = $oid"
 865                                 . ' AND pg_get_expr(adbin, adrelid) LIKE \'nextval(%\'',
 866                                 $fname
 867                         );
 868                         $row = $this->fetchObject( $res );
 869                         if ( $row ) {
 870                                 $this->query(
 871                                         'SELECT ' . preg_replace( '/^nextval\((.+)\)$/', 'setval($1,1,false)', $row->adsrc ),
 872                                         $fname
 873                                 );
 874                                 return true;
 875                         }
 876                         return false;
 877                 }
 878
 879                 return false;
 880         }
 881
 882         /**
 883          * @param string $prefix Only show tables with this prefix, e.g. mw_
 884          * @param string $fname Calling function name
 885          * @return string[]
 886          * @suppress SecurityCheck-SQLInjection array_map not recognized T204911
 887          */
 888         public function listTables( $prefix = '', $fname = __METHOD__ ) {
 889                 $eschemas = implode( ',', array_map( [ $this, 'addQuotes' ], $this->getCoreSchemas() ) );
 890                 $result = $this->query(
 891                         "SELECT DISTINCT tablename FROM pg_tables WHERE schemaname IN ($eschemas)", $fname );
 892                 $endArray = [];
 893
 894                 foreach ( $result as $table ) {
 895                         $vars = get_object_vars( $table );
 896                         $table = array_pop( $vars );
 897                         if ( $prefix == '' || strpos( $table, $prefix ) === 0 ) {
 898                                 $endArray[] = $table;
 899                         }
 900                 }
 901
 902                 return $endArray;
 903         }
 904
 905         public function timestamp( $ts = 0 ) {
 906                 $ct = new ConvertibleTimestamp( $ts );
 907
 908                 return $ct->getTimestamp( TS_POSTGRES );
 909         }
 910
 911         /**
 912          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
 913          * to https://www.php.net/manual/en/ref.pgsql.php
 914          *
 915          * Parsing a postgres array can be a tricky problem, he's my
 916          * take on this, it handles multi-dimensional arrays plus
 917          * escaping using a nasty regexp to determine the limits of each
 918          * data-item.
 919          *
 920          * This should really be handled by PHP PostgreSQL module
 921          *
 922          * @since 1.19
 923          * @param string $text Postgreql array returned in a text form like {a,b}
 924          * @param string[] $output
 925          * @param int|bool $limit
 926          * @param int $offset
 927          * @return string[]
 928          */
 929         private function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
 930                 if ( $limit === false ) {
 931                         $limit = strlen( $text ) - 1;
 932                         $output = [];
 933                 }
 934                 if ( $text == '{}' ) {
 935                         return $output;
 936                 }
 937                 do {
 938                         if ( $text[$offset] != '{' ) {
 939                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
 940                                         $text, $match, 0, $offset );
 941                                 $offset += strlen( $match[0] );
 942                                 $output[] = ( $match[1][0] != '"'
 943                                         ? $match[1]
 944                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
 945                                 if ( $match[3] == '},' ) {
 946                                         return $output;
 947                                 }
 948                         } else {
 949                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
 950                         }
 951                 } while ( $limit > $offset );
 952
 953                 return $output;
 954         }
 955
 956         public function aggregateValue( $valuedata, $valuename = 'value' ) {
 957                 return $valuedata;
 958         }
 959
 960         public function getSoftwareLink() {
 961                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
 962         }
 963
 964         /**
 965          * Return current schema (executes SELECT current_schema())
 966          * Needs transaction
 967          *
 968          * @since 1.19
 969          * @return string Default schema for the current session
 970          */
 971         public function getCurrentSchema() {
 972                 $res = $this->query( "SELECT current_schema()", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
 973                 $row = $this->fetchRow( $res );
 974
 975                 return $row[0];
 976         }
 977
 978         /**
 979          * Return list of schemas which are accessible without schema name
 980          * This is list does not contain magic keywords like "$user"
 981          * Needs transaction
 982          *
 983          * @see getSearchPath()
 984          * @see setSearchPath()
 985          * @since 1.19
 986          * @return array List of actual schemas for the current sesson
 987          */
 988         public function getSchemas() {
 989                 $res = $this->query(
 990                         "SELECT current_schemas(false)",
 991                         __METHOD__,
 992                         self::QUERY_IGNORE_DBO_TRX
 993                 );
 994                 $row = $this->fetchRow( $res );
 995                 $schemas = [];
 996
 997                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
 998
 999                 return $this->pg_array_parse( $row[0], $schemas );
1000         }
1001
1002         /**
1003          * Return search patch for schemas
1004          * This is different from getSchemas() since it contain magic keywords
1005          * (like "$user").
1006          * Needs transaction
1007          *
1008          * @since 1.19
1009          * @return array How to search for table names schemas for the current user
1010          */
1011         public function getSearchPath() {
1012                 $res = $this->query( "SHOW search_path", __METHOD__, self::QUERY_IGNORE_DBO_TRX );
1013                 $row = $this->fetchRow( $res );
1014
1015                 /* PostgreSQL returns SHOW values as strings */
1016
1017                 return explode( ",", $row[0] );
1018         }
1019
1020         /**
1021          * Update search_path, values should already be sanitized
1022          * Values may contain magic keywords like "$user"
1023          * @since 1.19
1024          *
1025          * @param array $search_path List of schemas to be searched by default
1026          */
1027         private function setSearchPath( $search_path ) {
1028                 $this->query(
1029                         "SET search_path = " . implode( ", ", $search_path ),
1030                         __METHOD__,
1031                         self::QUERY_IGNORE_DBO_TRX
1032                 );
1033         }
1034
1035         /**
1036          * Determine default schema for the current application
1037          * Adjust this session schema search path if desired schema exists
1038          * and is not alread there.
1039          *
1040          * We need to have name of the core schema stored to be able
1041          * to query database metadata.
1042          *
1043          * This will be also called by the installer after the schema is created
1044          *
1045          * @since 1.19
1046          *
1047          * @param string $desiredSchema
1048          */
1049         public function determineCoreSchema( $desiredSchema ) {
1050                 if ( $this->trxLevel() ) {
1051                         // We do not want the schema selection to change on ROLLBACK or INSERT SELECT.
1052                         // See https://www.postgresql.org/docs/8.3/sql-set.html
1053                         throw new DBUnexpectedError(
1054                                 $this,
1055                                 __METHOD__ . ": a transaction is currently active"
1056                         );
1057                 }
1058
1059                 if ( $this->schemaExists( $desiredSchema ) ) {
1060                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1061                                 $this->coreSchema = $desiredSchema;
1062                                 $this->queryLogger->debug(
1063                                         "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1064                         } else {
1065                                 /**
1066                                  * Prepend our schema (e.g. 'mediawiki') in front
1067                                  * of the search path
1068                                  * Fixes T17816
1069                                  */
1070                                 $search_path = $this->getSearchPath();
1071                                 array_unshift( $search_path, $this->addIdentifierQuotes( $desiredSchema ) );
1072                                 $this->setSearchPath( $search_path );
1073                                 $this->coreSchema = $desiredSchema;
1074                                 $this->queryLogger->debug(
1075                                         "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1076                         }
1077                 } else {
1078                         $this->coreSchema = $this->getCurrentSchema();
1079                         $this->queryLogger->debug(
1080                                 "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1081                                 $this->coreSchema . "\"\n" );
1082                 }
1083         }
1084
1085         /**
1086          * Return schema name for core application tables
1087          *
1088          * @since 1.19
1089          * @return string Core schema name
1090          */
1091         public function getCoreSchema() {
1092                 return $this->coreSchema;
1093         }
1094
1095         /**
1096          * Return schema names for temporary tables and core application tables
1097          *
1098          * @since 1.31
1099          * @return string[] schema names
1100          */
1101         public function getCoreSchemas() {
1102                 if ( $this->tempSchema ) {
1103                         return [ $this->tempSchema, $this->getCoreSchema() ];
1104                 }
1105
1106                 $res = $this->query(
1107                         "SELECT nspname FROM pg_catalog.pg_namespace n WHERE n.oid = pg_my_temp_schema()", __METHOD__
1108                 );
1109                 $row = $this->fetchObject( $res );
1110                 if ( $row ) {
1111                         $this->tempSchema = $row->nspname;
1112                         return [ $this->tempSchema, $this->getCoreSchema() ];
1113                 }
1114
1115                 return [ $this->getCoreSchema() ];
1116         }
1117
1118         public function getServerVersion() {
1119                 if ( !isset( $this->numericVersion ) ) {
1120                         $conn = $this->getBindingHandle();
1121                         $versionInfo = pg_version( $conn );
1122                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1123                                 // Old client, abort install
1124                                 $this->numericVersion = '7.3 or earlier';
1125                         } elseif ( isset( $versionInfo['server'] ) ) {
1126                                 // Normal client
1127                                 $this->numericVersion = $versionInfo['server'];
1128                         } else {
1129                                 // T18937: broken pgsql extension from PHP<5.3
1130                                 $this->numericVersion = pg_parameter_status( $conn, 'server_version' );
1131                         }
1132                 }
1133
1134                 return $this->numericVersion;
1135         }
1136
1137         /**
1138          * Query whether a given relation exists (in the given schema, or the
1139          * default mw one if not given)
1140          * @param string $table
1141          * @param array|string $types
1142          * @param bool|string $schema
1143          * @return bool
1144          */
1145         private function relationExists( $table, $types, $schema = false ) {
1146                 if ( !is_array( $types ) ) {
1147                         $types = [ $types ];
1148                 }
1149                 if ( $schema === false ) {
1150                         $schemas = $this->getCoreSchemas();
1151                 } else {
1152                         $schemas = [ $schema ];
1153                 }
1154                 $table = $this->realTableName( $table, 'raw' );
1155                 $etable = $this->addQuotes( $table );
1156                 foreach ( $schemas as $schema ) {
1157                         $eschema = $this->addQuotes( $schema );
1158                         $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1159                                 . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1160                                 . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1161                         $res = $this->query( $sql );
1162                         if ( $res && $res->numRows() ) {
1163                                 return true;
1164                         }
1165                 }
1166
1167                 return false;
1168         }
1169
1170         /**
1171          * For backward compatibility, this function checks both tables and views.
1172          * @param string $table
1173          * @param string $fname
1174          * @param bool|string $schema
1175          * @return bool
1176          */
1177         public function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1178                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1179         }
1180
1181         public function sequenceExists( $sequence, $schema = false ) {
1182                 return $this->relationExists( $sequence, 'S', $schema );
1183         }
1184
1185         public function triggerExists( $table, $trigger ) {
1186                 $q = <<<SQL
1187         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1188                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1189                         AND tgrelid=pg_class.oid
1190                         AND nspname=%s AND relname=%s AND tgname=%s
1191 SQL;
1192                 foreach ( $this->getCoreSchemas() as $schema ) {
1193                         $res = $this->query(
1194                                 sprintf(
1195                                         $q,
1196                                         $this->addQuotes( $schema ),
1197                                         $this->addQuotes( $table ),
1198                                         $this->addQuotes( $trigger )
1199                                 )
1200                         );
1201                         if ( $res && $res->numRows() ) {
1202                                 return true;
1203                         }
1204                 }
1205
1206                 return false;
1207         }
1208
1209         public function ruleExists( $table, $rule ) {
1210                 $exists = $this->selectField( 'pg_rules', 'rulename',
1211                         [
1212                                 'rulename' => $rule,
1213                                 'tablename' => $table,
1214                                 'schemaname' => $this->getCoreSchemas()
1215                         ]
1216                 );
1217
1218                 return $exists === $rule;
1219         }
1220
1221         public function constraintExists( $table, $constraint ) {
1222                 foreach ( $this->getCoreSchemas() as $schema ) {
1223                         $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1224                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1225                                 $this->addQuotes( $schema ),
1226                                 $this->addQuotes( $table ),
1227                                 $this->addQuotes( $constraint )
1228                         );
1229                         $res = $this->query( $sql );
1230                         if ( $res && $res->numRows() ) {
1231                                 return true;
1232                         }
1233                 }
1234                 return false;
1235         }
1236
1237         /**
1238          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1239          * @param string $schema
1240          * @return bool
1241          */
1242         public function schemaExists( $schema ) {
1243                 if ( !strlen( $schema ) ) {
1244                         return false; // short-circuit
1245                 }
1246
1247                 $res = $this->query(
1248                         "SELECT 1 FROM pg_catalog.pg_namespace " .
1249                         "WHERE nspname = " . $this->addQuotes( $schema ) . " LIMIT 1",
1250                         __METHOD__,
1251                         self::QUERY_IGNORE_DBO_TRX
1252                 );
1253
1254                 return ( $this->numRows( $res ) > 0 );
1255         }
1256
1257         /**
1258          * Returns true if a given role (i.e. user) exists, false otherwise.
1259          * @param string $roleName
1260          * @return bool
1261          */
1262         public function roleExists( $roleName ) {
1263                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1264                         [ 'rolname' => $roleName ], __METHOD__ );
1265
1266                 return (bool)$exists;
1267         }
1268
1269         /**
1270          * @param string $table
1271          * @param string $field
1272          * @return PostgresField|null
1273          */
1274         public function fieldInfo( $table, $field ) {
1275                 return PostgresField::fromText( $this, $table, $field );
1276         }
1277
1278         /**
1279          * pg_field_type() wrapper
1280          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1281          * @param int $index Field number, starting from 0
1282          * @return string
1283          */
1284         public function fieldType( $res, $index ) {
1285                 return pg_field_type( ResultWrapper::unwrap( $res ), $index );
1286         }
1287
1288         public function encodeBlob( $b ) {
1289                 return new PostgresBlob( pg_escape_bytea( $b ) );
1290         }
1291
1292         public function decodeBlob( $b ) {
1293                 if ( $b instanceof PostgresBlob ) {
1294                         $b = $b->fetch();
1295                 } elseif ( $b instanceof Blob ) {
1296                         return $b->fetch();
1297                 }
1298
1299                 return pg_unescape_bytea( $b );
1300         }
1301
1302         public function strencode( $s ) {
1303                 // Should not be called by us
1304                 return pg_escape_string( $this->getBindingHandle(), (string)$s );
1305         }
1306
1307         public function addQuotes( $s ) {
1308                 $conn = $this->getBindingHandle();
1309
1310                 if ( is_null( $s ) ) {
1311                         return 'NULL';
1312                 } elseif ( is_bool( $s ) ) {
1313                         return intval( $s );
1314                 } elseif ( $s instanceof Blob ) {
1315                         if ( $s instanceof PostgresBlob ) {
1316                                 $s = $s->fetch();
1317                         } else {
1318                                 $s = pg_escape_bytea( $conn, $s->fetch() );
1319                         }
1320                         return "'$s'";
1321                 } elseif ( $s instanceof NextSequenceValue ) {
1322                         return 'DEFAULT';
1323                 }
1324
1325                 return "'" . pg_escape_string( $conn, (string)$s ) . "'";
1326         }
1327
1328         public function makeSelectOptions( $options ) {
1329                 $preLimitTail = $postLimitTail = '';
1330                 $startOpts = $useIndex = $ignoreIndex = '';
1331
1332                 $noKeyOptions = [];
1333                 foreach ( $options as $key => $option ) {
1334                         if ( is_numeric( $key ) ) {
1335                                 $noKeyOptions[$option] = true;
1336                         }
1337                 }
1338
1339                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1340
1341                 $preLimitTail .= $this->makeOrderBy( $options );
1342
1343                 if ( isset( $options['FOR UPDATE'] ) ) {
1344                         $postLimitTail .= ' FOR UPDATE OF ' .
1345                                 implode( ', ', array_map( [ $this, 'tableName' ], $options['FOR UPDATE'] ) );
1346                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1347                         $postLimitTail .= ' FOR UPDATE';
1348                 }
1349
1350                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1351                         $startOpts .= 'DISTINCT';
1352                 }
1353
1354                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1355         }
1356
1357         public function buildConcat( $stringList ) {
1358                 return implode( ' || ', $stringList );
1359         }
1360
1361         public function buildGroupConcatField(
1362                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1363         ) {
1364                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1365
1366                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1367         }
1368
1369         public function buildStringCast( $field ) {
1370                 return $field . '::text';
1371         }
1372
1373         public function streamStatementEnd( &$sql, &$newLine ) {
1374                 # Allow dollar quoting for function declarations
1375                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1376                         if ( $this->delimiter ) {
1377                                 $this->delimiter = false;
1378                         } else {
1379                                 $this->delimiter = ';';
1380                         }
1381                 }
1382
1383                 return parent::streamStatementEnd( $sql, $newLine );
1384         }
1385
1386         public function doLockTables( array $read, array $write, $method ) {
1387                 $tablesWrite = [];
1388                 foreach ( $write as $table ) {
1389                         $tablesWrite[] = $this->tableName( $table );
1390                 }
1391                 $tablesRead = [];
1392                 foreach ( $read as $table ) {
1393                         $tablesRead[] = $this->tableName( $table );
1394                 }
1395
1396                 // Acquire locks for the duration of the current transaction...
1397                 if ( $tablesWrite ) {
1398                         $this->query(
1399                                 'LOCK TABLE ONLY ' . implode( ',', $tablesWrite ) . ' IN EXCLUSIVE MODE',
1400                                 $method
1401                         );
1402                 }
1403                 if ( $tablesRead ) {
1404                         $this->query(
1405                                 'LOCK TABLE ONLY ' . implode( ',', $tablesRead ) . ' IN SHARE MODE',
1406                                 $method
1407                         );
1408                 }
1409
1410                 return true;
1411         }
1412
1413         public function lockIsFree( $lockName, $method ) {
1414                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1415                         return false; // already held
1416                 }
1417                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1418                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1419                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1420                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1421                 $row = $this->fetchObject( $result );
1422
1423                 return ( $row->lockstatus === 't' );
1424         }
1425
1426         public function lock( $lockName, $method, $timeout = 5 ) {
1427                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1428                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1429                 $loop = new WaitConditionLoop(
1430                         function () use ( $lockName, $key, $timeout, $method ) {
1431                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1432                                 $row = $this->fetchObject( $res );
1433                                 if ( $row->lockstatus === 't' ) {
1434                                         parent::lock( $lockName, $method, $timeout ); // record
1435                                         return true;
1436                                 }
1437
1438                                 return WaitConditionLoop::CONDITION_CONTINUE;
1439                         },
1440                         $timeout
1441                 );
1442
1443                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1444         }
1445
1446         public function unlock( $lockName, $method ) {
1447                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1448                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1449                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1450                 $row = $this->fetchObject( $result );
1451
1452                 if ( $row->lockstatus === 't' ) {
1453                         parent::unlock( $lockName, $method ); // record
1454                         return true;
1455                 }
1456
1457                 $this->queryLogger->debug( __METHOD__ . " failed to release lock\n" );
1458
1459                 return false;
1460         }
1461
1462         public function serverIsReadOnly() {
1463                 $res = $this->query( "SHOW default_transaction_read_only", __METHOD__ );
1464                 $row = $this->fetchObject( $res );
1465
1466                 return $row ? ( strtolower( $row->default_transaction_read_only ) === 'on' ) : false;
1467         }
1468
1469         public static function getAttributes() {
1470                 return [ self::ATTR_SCHEMAS_AS_TABLE_GROUPS => true ];
1471         }
1472
1473         /**
1474          * @param string $lockName
1475          * @return string Integer
1476          */
1477         private function bigintFromLockName( $lockName ) {
1478                 return \Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1479         }
1480 }
1481
1482 /**
1483  * @deprecated since 1.29
1484  */
1485 class_alias( DatabasePostgres::class, 'DatabasePostgres' );