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 ) {
  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                 $this->dbName = $dbName;
 104
 105                 $connectVars = [
 106                         // pg_connect() user $user as the default database. Since a database is *required*,
 107                         // at least pick a "don't care" database that is more likely to exist. This case
 108                         // arrises when LoadBalancer::getConnection( $i, [], '' ) is used.
 109                         'dbname' => strlen( $dbName ) ? $dbName : 'postgres',
 110                         'user' => $user,
 111                         'password' => $password
 112                 ];
 113                 if ( $server != false && $server != '' ) {
 114                         $connectVars['host'] = $server;
 115                 }
 116                 if ( (int)$this->port > 0 ) {
 117                         $connectVars['port'] = (int)$this->port;
 118                 }
 119                 if ( $this->flags & self::DBO_SSL ) {
 120                         $connectVars['sslmode'] = 1;
 121                 }
 122
 123                 $this->connectString = $this->makeConnectionString( $connectVars );
 124                 $this->close();
 125                 $this->installErrorHandler();
 126
 127                 try {
 128                         // Use new connections to let LoadBalancer/LBFactory handle reuse
 129                         $this->conn = pg_connect( $this->connectString, PGSQL_CONNECT_FORCE_NEW );
 130                 } catch ( Exception $ex ) {
 131                         $this->restoreErrorHandler();
 132                         throw $ex;
 133                 }
 134
 135                 $phpError = $this->restoreErrorHandler();
 136
 137                 if ( !$this->conn ) {
 138                         $this->queryLogger->debug(
 139                                 "DB connection error\n" .
 140                                 "Server: $server, Database: $dbName, User: $user, Password: " .
 141                                 substr( $password, 0, 3 ) . "...\n"
 142                         );
 143                         $this->queryLogger->debug( $this->lastError() . "\n" );
 144                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 145                 }
 146
 147                 $this->opened = true;
 148
 149                 # If called from the command-line (e.g. importDump), only show errors
 150                 if ( $this->cliMode ) {
 151                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 152                 }
 153
 154                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 155                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 156                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 157                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 158                 $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 159
 160                 $this->determineCoreSchema( $this->schema );
 161                 // The schema to be used is now in the search path; no need for explicit qualification
 162                 $this->schema = '';
 163
 164                 return $this->conn;
 165         }
 166
 167         public function databasesAreIndependent() {
 168                 return true;
 169         }
 170
 171         /**
 172          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 173          * DB name doesn't match the open connection, open a new one
 174          * @param string $db
 175          * @return bool
 176          * @throws DBUnexpectedError
 177          */
 178         public function selectDB( $db ) {
 179                 if ( $this->dbName !== $db ) {
 180                         return (bool)$this->open( $this->server, $this->user, $this->password, $db );
 181                 } else {
 182                         return true;
 183                 }
 184         }
 185
 186         /**
 187          * @param string[] $vars
 188          * @return string
 189          */
 190         private function makeConnectionString( $vars ) {
 191                 $s = '';
 192                 foreach ( $vars as $name => $value ) {
 193                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 194                 }
 195
 196                 return $s;
 197         }
 198
 199         protected function closeConnection() {
 200                 return $this->conn ? pg_close( $this->conn ) : true;
 201         }
 202
 203         protected function isTransactableQuery( $sql ) {
 204                 return parent::isTransactableQuery( $sql ) &&
 205                         !preg_match( '/^SELECT\s+pg_(try_|)advisory_\w+\(/', $sql );
 206         }
 207
 208         public function doQuery( $sql ) {
 209                 $conn = $this->getBindingHandle();
 210
 211                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 212                 // Clear previously left over PQresult
 213                 while ( $res = pg_get_result( $conn ) ) {
 214                         pg_free_result( $res );
 215                 }
 216                 if ( pg_send_query( $conn, $sql ) === false ) {
 217                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 218                 }
 219                 $this->lastResultHandle = pg_get_result( $conn );
 220                 if ( pg_result_error( $this->lastResultHandle ) ) {
 221                         return false;
 222                 }
 223
 224                 return $this->lastResultHandle;
 225         }
 226
 227         protected function dumpError() {
 228                 $diags = [
 229                         PGSQL_DIAG_SEVERITY,
 230                         PGSQL_DIAG_SQLSTATE,
 231                         PGSQL_DIAG_MESSAGE_PRIMARY,
 232                         PGSQL_DIAG_MESSAGE_DETAIL,
 233                         PGSQL_DIAG_MESSAGE_HINT,
 234                         PGSQL_DIAG_STATEMENT_POSITION,
 235                         PGSQL_DIAG_INTERNAL_POSITION,
 236                         PGSQL_DIAG_INTERNAL_QUERY,
 237                         PGSQL_DIAG_CONTEXT,
 238                         PGSQL_DIAG_SOURCE_FILE,
 239                         PGSQL_DIAG_SOURCE_LINE,
 240                         PGSQL_DIAG_SOURCE_FUNCTION
 241                 ];
 242                 foreach ( $diags as $d ) {
 243                         $this->queryLogger->debug( sprintf( "PgSQL ERROR(%d): %s\n",
 244                                 $d, pg_result_error_field( $this->lastResultHandle, $d ) ) );
 245                 }
 246         }
 247
 248         public function freeResult( $res ) {
 249                 if ( $res instanceof ResultWrapper ) {
 250                         $res = $res->result;
 251                 }
 252                 Wikimedia\suppressWarnings();
 253                 $ok = pg_free_result( $res );
 254                 Wikimedia\restoreWarnings();
 255                 if ( !$ok ) {
 256                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 257                 }
 258         }
 259
 260         public function fetchObject( $res ) {
 261                 if ( $res instanceof ResultWrapper ) {
 262                         $res = $res->result;
 263                 }
 264                 Wikimedia\suppressWarnings();
 265                 $row = pg_fetch_object( $res );
 266                 Wikimedia\restoreWarnings();
 267                 # @todo FIXME: HACK HACK HACK HACK debug
 268
 269                 # @todo hashar: not sure if the following test really trigger if the object
 270                 #          fetching failed.
 271                 $conn = $this->getBindingHandle();
 272                 if ( pg_last_error( $conn ) ) {
 273                         throw new DBUnexpectedError(
 274                                 $this,
 275                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 276                         );
 277                 }
 278
 279                 return $row;
 280         }
 281
 282         public function fetchRow( $res ) {
 283                 if ( $res instanceof ResultWrapper ) {
 284                         $res = $res->result;
 285                 }
 286                 Wikimedia\suppressWarnings();
 287                 $row = pg_fetch_array( $res );
 288                 Wikimedia\restoreWarnings();
 289
 290                 $conn = $this->getBindingHandle();
 291                 if ( pg_last_error( $conn ) ) {
 292                         throw new DBUnexpectedError(
 293                                 $this,
 294                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 295                         );
 296                 }
 297
 298                 return $row;
 299         }
 300
 301         public function numRows( $res ) {
 302                 if ( $res === false ) {
 303                         return 0;
 304                 }
 305
 306                 if ( $res instanceof ResultWrapper ) {
 307                         $res = $res->result;
 308                 }
 309                 Wikimedia\suppressWarnings();
 310                 $n = pg_num_rows( $res );
 311                 Wikimedia\restoreWarnings();
 312
 313                 $conn = $this->getBindingHandle();
 314                 if ( pg_last_error( $conn ) ) {
 315                         throw new DBUnexpectedError(
 316                                 $this,
 317                                 'SQL error: ' . htmlspecialchars( pg_last_error( $conn ) )
 318                         );
 319                 }
 320
 321                 return $n;
 322         }
 323
 324         public function numFields( $res ) {
 325                 if ( $res instanceof ResultWrapper ) {
 326                         $res = $res->result;
 327                 }
 328
 329                 return pg_num_fields( $res );
 330         }
 331
 332         public function fieldName( $res, $n ) {
 333                 if ( $res instanceof ResultWrapper ) {
 334                         $res = $res->result;
 335                 }
 336
 337                 return pg_field_name( $res, $n );
 338         }
 339
 340         public function insertId() {
 341                 $res = $this->query( "SELECT lastval()" );
 342                 $row = $this->fetchRow( $res );
 343                 return is_null( $row[0] ) ? null : (int)$row[0];
 344         }
 345
 346         public function dataSeek( $res, $row ) {
 347                 if ( $res instanceof ResultWrapper ) {
 348                         $res = $res->result;
 349                 }
 350
 351                 return pg_result_seek( $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         /**
 646          * INSERT SELECT wrapper
 647          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 648          * Source items may be literals rather then field names, but strings should
 649          * be quoted with Database::addQuotes()
 650          * $conds may be "*" to copy the whole table
 651          * srcTable may be an array of tables.
 652          * @todo FIXME: Implement this a little better (separate select/insert)?
 653          *
 654          * @param string $destTable
 655          * @param array|string $srcTable
 656          * @param array $varMap
 657          * @param array $conds
 658          * @param string $fname
 659          * @param array $insertOptions
 660          * @param array $selectOptions
 661          * @param array $selectJoinConds
 662          * @return bool
 663          */
 664         public function nativeInsertSelect(
 665                 $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 666                 $insertOptions = [], $selectOptions = [], $selectJoinConds = []
 667         ) {
 668                 if ( !is_array( $insertOptions ) ) {
 669                         $insertOptions = [ $insertOptions ];
 670                 }
 671
 672                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 673                         if ( $this->getServerVersion() >= 9.5 ) {
 674                                 // Use ON CONFLICT DO NOTHING if we have it for IGNORE
 675                                 $destTable = $this->tableName( $destTable );
 676
 677                                 $selectSql = $this->selectSQLText(
 678                                         $srcTable,
 679                                         array_values( $varMap ),
 680                                         $conds,
 681                                         $fname,
 682                                         $selectOptions,
 683                                         $selectJoinConds
 684                                 );
 685
 686                                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ') ' .
 687                                         $selectSql . ' ON CONFLICT DO NOTHING';
 688
 689                                 return $this->query( $sql, $fname );
 690                         } else {
 691                                 // IGNORE and we don't have ON CONFLICT DO NOTHING, so just use the non-native version
 692                                 return $this->nonNativeInsertSelect(
 693                                         $destTable, $srcTable, $varMap, $conds, $fname,
 694                                         $insertOptions, $selectOptions, $selectJoinConds
 695                                 );
 696                         }
 697                 }
 698
 699                 return parent::nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname,
 700                         $insertOptions, $selectOptions, $selectJoinConds );
 701         }
 702
 703         public function tableName( $name, $format = 'quoted' ) {
 704                 // Replace reserved words with better ones
 705                 $name = $this->remappedTableName( $name );
 706
 707                 return parent::tableName( $name, $format );
 708         }
 709
 710         /**
 711          * @param string $name
 712          * @return string Value of $name or remapped name if $name is a reserved keyword
 713          */
 714         public function remappedTableName( $name ) {
 715                 return $this->keywordTableMap[$name] ?? $name;
 716         }
 717
 718         /**
 719          * @param string $name
 720          * @param string $format
 721          * @return string Qualified and encoded (if requested) table name
 722          */
 723         public function realTableName( $name, $format = 'quoted' ) {
 724                 return parent::tableName( $name, $format );
 725         }
 726
 727         public function nextSequenceValue( $seqName ) {
 728                 return new NextSequenceValue;
 729         }
 730
 731         /**
 732          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 733          *
 734          * @param string $seqName
 735          * @return int
 736          */
 737         public function currentSequenceValue( $seqName ) {
 738                 $safeseq = str_replace( "'", "''", $seqName );
 739                 $res = $this->query( "SELECT currval('$safeseq')" );
 740                 $row = $this->fetchRow( $res );
 741                 $currval = $row[0];
 742
 743                 return $currval;
 744         }
 745
 746         public function textFieldSize( $table, $field ) {
 747                 $table = $this->tableName( $table );
 748                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 749                         FROM pg_class c, pg_attribute a, pg_type t
 750                         WHERE relname='$table' AND a.attrelid=c.oid AND
 751                                 a.atttypid=t.oid and a.attname='$field'";
 752                 $res = $this->query( $sql );
 753                 $row = $this->fetchObject( $res );
 754                 if ( $row->ftype == 'varchar' ) {
 755                         $size = $row->size - 4;
 756                 } else {
 757                         $size = $row->size;
 758                 }
 759
 760                 return $size;
 761         }
 762
 763         public function limitResult( $sql, $limit, $offset = false ) {
 764                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 765         }
 766
 767         public function wasDeadlock() {
 768                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 769                 return $this->lastErrno() === '40P01';
 770         }
 771
 772         public function wasLockTimeout() {
 773                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 774                 return $this->lastErrno() === '55P03';
 775         }
 776
 777         public function wasConnectionError( $errno ) {
 778                 // https://www.postgresql.org/docs/9.2/static/errcodes-appendix.html
 779                 static $codes = [ '08000', '08003', '08006', '08001', '08004', '57P01', '57P03', '53300' ];
 780
 781                 return in_array( $errno, $codes, true );
 782         }
 783
 784         protected function wasKnownStatementRollbackError() {
 785                 return false; // transaction has to be rolled-back from error state
 786         }
 787
 788         public function duplicateTableStructure(
 789                 $oldName, $newName, $temporary = false, $fname = __METHOD__
 790         ) {
 791                 $newNameE = $this->addIdentifierQuotes( $newName );
 792                 $oldNameE = $this->addIdentifierQuotes( $oldName );
 793
 794                 $temporary = $temporary ? 'TEMPORARY' : '';
 795
 796                 $ret = $this->query( "CREATE $temporary TABLE $newNameE " .
 797                         "(LIKE $oldNameE INCLUDING DEFAULTS INCLUDING INDEXES)", $fname );
 798                 if ( !$ret ) {
 799                         return $ret;
 800                 }
 801
 802                 $res = $this->query( 'SELECT attname FROM pg_class c'
 803                         . ' JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 804                         . ' JOIN pg_attribute a ON (a.attrelid = c.oid)'
 805                         . ' JOIN pg_attrdef d ON (c.oid=d.adrelid and a.attnum=d.adnum)'
 806                         . ' WHERE relkind = \'r\''
 807                         . ' AND nspname = ' . $this->addQuotes( $this->getCoreSchema() )
 808                         . ' AND relname = ' . $this->addQuotes( $oldName )
 809                         . ' AND adsrc LIKE \'nextval(%\'',
 810                         $fname
 811                 );
 812                 $row = $this->fetchObject( $res );
 813                 if ( $row ) {
 814                         $field = $row->attname;
 815                         $newSeq = "{$newName}_{$field}_seq";
 816                         $fieldE = $this->addIdentifierQuotes( $field );
 817                         $newSeqE = $this->addIdentifierQuotes( $newSeq );
 818                         $newSeqQ = $this->addQuotes( $newSeq );
 819                         $this->query( "CREATE $temporary SEQUENCE $newSeqE OWNED BY $newNameE.$fieldE", $fname );
 820                         $this->query(
 821                                 "ALTER TABLE $newNameE ALTER COLUMN $fieldE SET DEFAULT nextval({$newSeqQ}::regclass)",
 822                                 $fname
 823                         );
 824                 }
 825
 826                 return $ret;
 827         }
 828
 829         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
 830                 $table = $this->tableName( $table, 'raw' );
 831                 foreach ( $this->getCoreSchemas() as $schema ) {
 832                         $res = $this->query(
 833                                 'SELECT c.oid FROM pg_class c JOIN pg_namespace n ON (n.oid = c.relnamespace)'
 834                                 . ' WHERE relkind = \'r\''
 835                                 . ' AND nspname = ' . $this->addQuotes( $schema )
 836                                 . ' AND relname = ' . $this->addQuotes( $table ),
 837                                 $fname
 838                         );
 839                         if ( !$res || !$this->numRows( $res ) ) {
 840                                 continue;
 841                         }
 842
 843                         $oid = $this->fetchObject( $res )->oid;
 844                         $res = $this->query( 'SELECT adsrc FROM pg_attribute a'
 845                                 . ' JOIN pg_attrdef d ON (a.attrelid=d.adrelid and a.attnum=d.adnum)'
 846                                 . " WHERE a.attrelid = $oid"
 847                                 . ' AND adsrc LIKE \'nextval(%\'',
 848                                 $fname
 849                         );
 850                         $row = $this->fetchObject( $res );
 851                         if ( $row ) {
 852                                 $this->query(
 853                                         'SELECT ' . preg_replace( '/^nextval\((.+)\)$/', 'setval($1,1,false)', $row->adsrc ),
 854                                         $fname
 855                                 );
 856                                 return true;
 857                         }
 858                         return false;
 859                 }
 860
 861                 return false;
 862         }
 863
 864         /**
 865          * @suppress SecurityCheck-SQLInjection array_map not recognized T204911
 866          */
 867         public function listTables( $prefix = null, $fname = __METHOD__ ) {
 868                 $eschemas = implode( ',', array_map( [ $this, 'addQuotes' ], $this->getCoreSchemas() ) );
 869                 $result = $this->query(
 870                         "SELECT DISTINCT tablename FROM pg_tables WHERE schemaname IN ($eschemas)", $fname );
 871                 $endArray = [];
 872
 873                 foreach ( $result as $table ) {
 874                         $vars = get_object_vars( $table );
 875                         $table = array_pop( $vars );
 876                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
 877                                 $endArray[] = $table;
 878                         }
 879                 }
 880
 881                 return $endArray;
 882         }
 883
 884         public function timestamp( $ts = 0 ) {
 885                 $ct = new ConvertibleTimestamp( $ts );
 886
 887                 return $ct->getTimestamp( TS_POSTGRES );
 888         }
 889
 890         /**
 891          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
 892          * to https://secure.php.net/manual/en/ref.pgsql.php
 893          *
 894          * Parsing a postgres array can be a tricky problem, he's my
 895          * take on this, it handles multi-dimensional arrays plus
 896          * escaping using a nasty regexp to determine the limits of each
 897          * data-item.
 898          *
 899          * This should really be handled by PHP PostgreSQL module
 900          *
 901          * @since 1.19
 902          * @param string $text Postgreql array returned in a text form like {a,b}
 903          * @param string[] $output
 904          * @param int|bool $limit
 905          * @param int $offset
 906          * @return string[]
 907          */
 908         private function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
 909                 if ( false === $limit ) {
 910                         $limit = strlen( $text ) - 1;
 911                         $output = [];
 912                 }
 913                 if ( '{}' == $text ) {
 914                         return $output;
 915                 }
 916                 do {
 917                         if ( '{' != $text[$offset] ) {
 918                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
 919                                         $text, $match, 0, $offset );
 920                                 $offset += strlen( $match[0] );
 921                                 $output[] = ( '"' != $match[1][0]
 922                                         ? $match[1]
 923                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
 924                                 if ( '},' == $match[3] ) {
 925                                         return $output;
 926                                 }
 927                         } else {
 928                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
 929                         }
 930                 } while ( $limit > $offset );
 931
 932                 return $output;
 933         }
 934
 935         public function aggregateValue( $valuedata, $valuename = 'value' ) {
 936                 return $valuedata;
 937         }
 938
 939         public function getSoftwareLink() {
 940                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
 941         }
 942
 943         /**
 944          * Return current schema (executes SELECT current_schema())
 945          * Needs transaction
 946          *
 947          * @since 1.19
 948          * @return string Default schema for the current session
 949          */
 950         public function getCurrentSchema() {
 951                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
 952                 $row = $this->fetchRow( $res );
 953
 954                 return $row[0];
 955         }
 956
 957         /**
 958          * Return list of schemas which are accessible without schema name
 959          * This is list does not contain magic keywords like "$user"
 960          * Needs transaction
 961          *
 962          * @see getSearchPath()
 963          * @see setSearchPath()
 964          * @since 1.19
 965          * @return array List of actual schemas for the current sesson
 966          */
 967         public function getSchemas() {
 968                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
 969                 $row = $this->fetchRow( $res );
 970                 $schemas = [];
 971
 972                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
 973
 974                 return $this->pg_array_parse( $row[0], $schemas );
 975         }
 976
 977         /**
 978          * Return search patch for schemas
 979          * This is different from getSchemas() since it contain magic keywords
 980          * (like "$user").
 981          * Needs transaction
 982          *
 983          * @since 1.19
 984          * @return array How to search for table names schemas for the current user
 985          */
 986         public function getSearchPath() {
 987                 $res = $this->query( "SHOW search_path", __METHOD__ );
 988                 $row = $this->fetchRow( $res );
 989
 990                 /* PostgreSQL returns SHOW values as strings */
 991
 992                 return explode( ",", $row[0] );
 993         }
 994
 995         /**
 996          * Update search_path, values should already be sanitized
 997          * Values may contain magic keywords like "$user"
 998          * @since 1.19
 999          *
1000          * @param array $search_path List of schemas to be searched by default
1001          */
1002         private function setSearchPath( $search_path ) {
1003                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1004         }
1005
1006         /**
1007          * Determine default schema for the current application
1008          * Adjust this session schema search path if desired schema exists
1009          * and is not alread there.
1010          *
1011          * We need to have name of the core schema stored to be able
1012          * to query database metadata.
1013          *
1014          * This will be also called by the installer after the schema is created
1015          *
1016          * @since 1.19
1017          *
1018          * @param string $desiredSchema
1019          */
1020         public function determineCoreSchema( $desiredSchema ) {
1021                 $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
1022                 if ( $this->schemaExists( $desiredSchema ) ) {
1023                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1024                                 $this->coreSchema = $desiredSchema;
1025                                 $this->queryLogger->debug(
1026                                         "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1027                         } else {
1028                                 /**
1029                                  * Prepend our schema (e.g. 'mediawiki') in front
1030                                  * of the search path
1031                                  * Fixes T17816
1032                                  */
1033                                 $search_path = $this->getSearchPath();
1034                                 array_unshift( $search_path,
1035                                         $this->addIdentifierQuotes( $desiredSchema ) );
1036                                 $this->setSearchPath( $search_path );
1037                                 $this->coreSchema = $desiredSchema;
1038                                 $this->queryLogger->debug(
1039                                         "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1040                         }
1041                 } else {
1042                         $this->coreSchema = $this->getCurrentSchema();
1043                         $this->queryLogger->debug(
1044                                 "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1045                                 $this->coreSchema . "\"\n" );
1046                 }
1047                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1048                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
1049         }
1050
1051         /**
1052          * Return schema name for core application tables
1053          *
1054          * @since 1.19
1055          * @return string Core schema name
1056          */
1057         public function getCoreSchema() {
1058                 return $this->coreSchema;
1059         }
1060
1061         /**
1062          * Return schema names for temporary tables and core application tables
1063          *
1064          * @since 1.31
1065          * @return string[] schema names
1066          */
1067         public function getCoreSchemas() {
1068                 if ( $this->tempSchema ) {
1069                         return [ $this->tempSchema, $this->getCoreSchema() ];
1070                 }
1071
1072                 $res = $this->query(
1073                         "SELECT nspname FROM pg_catalog.pg_namespace n WHERE n.oid = pg_my_temp_schema()", __METHOD__
1074                 );
1075                 $row = $this->fetchObject( $res );
1076                 if ( $row ) {
1077                         $this->tempSchema = $row->nspname;
1078                         return [ $this->tempSchema, $this->getCoreSchema() ];
1079                 }
1080
1081                 return [ $this->getCoreSchema() ];
1082         }
1083
1084         public function getServerVersion() {
1085                 if ( !isset( $this->numericVersion ) ) {
1086                         $conn = $this->getBindingHandle();
1087                         $versionInfo = pg_version( $conn );
1088                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1089                                 // Old client, abort install
1090                                 $this->numericVersion = '7.3 or earlier';
1091                         } elseif ( isset( $versionInfo['server'] ) ) {
1092                                 // Normal client
1093                                 $this->numericVersion = $versionInfo['server'];
1094                         } else {
1095                                 // T18937: broken pgsql extension from PHP<5.3
1096                                 $this->numericVersion = pg_parameter_status( $conn, 'server_version' );
1097                         }
1098                 }
1099
1100                 return $this->numericVersion;
1101         }
1102
1103         /**
1104          * Query whether a given relation exists (in the given schema, or the
1105          * default mw one if not given)
1106          * @param string $table
1107          * @param array|string $types
1108          * @param bool|string $schema
1109          * @return bool
1110          */
1111         private function relationExists( $table, $types, $schema = false ) {
1112                 if ( !is_array( $types ) ) {
1113                         $types = [ $types ];
1114                 }
1115                 if ( $schema === false ) {
1116                         $schemas = $this->getCoreSchemas();
1117                 } else {
1118                         $schemas = [ $schema ];
1119                 }
1120                 $table = $this->realTableName( $table, 'raw' );
1121                 $etable = $this->addQuotes( $table );
1122                 foreach ( $schemas as $schema ) {
1123                         $eschema = $this->addQuotes( $schema );
1124                         $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1125                                 . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1126                                 . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1127                         $res = $this->query( $sql );
1128                         if ( $res && $res->numRows() ) {
1129                                 return true;
1130                         }
1131                 }
1132
1133                 return false;
1134         }
1135
1136         /**
1137          * For backward compatibility, this function checks both tables and views.
1138          * @param string $table
1139          * @param string $fname
1140          * @param bool|string $schema
1141          * @return bool
1142          */
1143         public function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1144                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1145         }
1146
1147         public function sequenceExists( $sequence, $schema = false ) {
1148                 return $this->relationExists( $sequence, 'S', $schema );
1149         }
1150
1151         public function triggerExists( $table, $trigger ) {
1152                 $q = <<<SQL
1153         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1154                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1155                         AND tgrelid=pg_class.oid
1156                         AND nspname=%s AND relname=%s AND tgname=%s
1157 SQL;
1158                 foreach ( $this->getCoreSchemas() as $schema ) {
1159                         $res = $this->query(
1160                                 sprintf(
1161                                         $q,
1162                                         $this->addQuotes( $schema ),
1163                                         $this->addQuotes( $table ),
1164                                         $this->addQuotes( $trigger )
1165                                 )
1166                         );
1167                         if ( $res && $res->numRows() ) {
1168                                 return true;
1169                         }
1170                 }
1171
1172                 return false;
1173         }
1174
1175         public function ruleExists( $table, $rule ) {
1176                 $exists = $this->selectField( 'pg_rules', 'rulename',
1177                         [
1178                                 'rulename' => $rule,
1179                                 'tablename' => $table,
1180                                 'schemaname' => $this->getCoreSchemas()
1181                         ]
1182                 );
1183
1184                 return $exists === $rule;
1185         }
1186
1187         public function constraintExists( $table, $constraint ) {
1188                 foreach ( $this->getCoreSchemas() as $schema ) {
1189                         $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1190                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1191                                 $this->addQuotes( $schema ),
1192                                 $this->addQuotes( $table ),
1193                                 $this->addQuotes( $constraint )
1194                         );
1195                         $res = $this->query( $sql );
1196                         if ( $res && $res->numRows() ) {
1197                                 return true;
1198                         }
1199                 }
1200                 return false;
1201         }
1202
1203         /**
1204          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1205          * @param string $schema
1206          * @return bool
1207          */
1208         public function schemaExists( $schema ) {
1209                 if ( !strlen( $schema ) ) {
1210                         return false; // short-circuit
1211                 }
1212
1213                 $exists = $this->selectField(
1214                         '"pg_catalog"."pg_namespace"', 1, [ 'nspname' => $schema ], __METHOD__ );
1215
1216                 return (bool)$exists;
1217         }
1218
1219         /**
1220          * Returns true if a given role (i.e. user) exists, false otherwise.
1221          * @param string $roleName
1222          * @return bool
1223          */
1224         public function roleExists( $roleName ) {
1225                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1226                         [ 'rolname' => $roleName ], __METHOD__ );
1227
1228                 return (bool)$exists;
1229         }
1230
1231         /**
1232          * @param string $table
1233          * @param string $field
1234          * @return PostgresField|null
1235          */
1236         public function fieldInfo( $table, $field ) {
1237                 return PostgresField::fromText( $this, $table, $field );
1238         }
1239
1240         /**
1241          * pg_field_type() wrapper
1242          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1243          * @param int $index Field number, starting from 0
1244          * @return string
1245          */
1246         public function fieldType( $res, $index ) {
1247                 if ( $res instanceof ResultWrapper ) {
1248                         $res = $res->result;
1249                 }
1250
1251                 return pg_field_type( $res, $index );
1252         }
1253
1254         public function encodeBlob( $b ) {
1255                 return new PostgresBlob( pg_escape_bytea( $b ) );
1256         }
1257
1258         public function decodeBlob( $b ) {
1259                 if ( $b instanceof PostgresBlob ) {
1260                         $b = $b->fetch();
1261                 } elseif ( $b instanceof Blob ) {
1262                         return $b->fetch();
1263                 }
1264
1265                 return pg_unescape_bytea( $b );
1266         }
1267
1268         public function strencode( $s ) {
1269                 // Should not be called by us
1270                 return pg_escape_string( $this->getBindingHandle(), (string)$s );
1271         }
1272
1273         public function addQuotes( $s ) {
1274                 $conn = $this->getBindingHandle();
1275
1276                 if ( is_null( $s ) ) {
1277                         return 'NULL';
1278                 } elseif ( is_bool( $s ) ) {
1279                         return intval( $s );
1280                 } elseif ( $s instanceof Blob ) {
1281                         if ( $s instanceof PostgresBlob ) {
1282                                 $s = $s->fetch();
1283                         } else {
1284                                 $s = pg_escape_bytea( $conn, $s->fetch() );
1285                         }
1286                         return "'$s'";
1287                 } elseif ( $s instanceof NextSequenceValue ) {
1288                         return 'DEFAULT';
1289                 }
1290
1291                 return "'" . pg_escape_string( $conn, (string)$s ) . "'";
1292         }
1293
1294         public function makeSelectOptions( $options ) {
1295                 $preLimitTail = $postLimitTail = '';
1296                 $startOpts = $useIndex = $ignoreIndex = '';
1297
1298                 $noKeyOptions = [];
1299                 foreach ( $options as $key => $option ) {
1300                         if ( is_numeric( $key ) ) {
1301                                 $noKeyOptions[$option] = true;
1302                         }
1303                 }
1304
1305                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1306
1307                 $preLimitTail .= $this->makeOrderBy( $options );
1308
1309                 if ( isset( $options['FOR UPDATE'] ) ) {
1310                         $postLimitTail .= ' FOR UPDATE OF ' .
1311                                 implode( ', ', array_map( [ $this, 'tableName' ], $options['FOR UPDATE'] ) );
1312                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1313                         $postLimitTail .= ' FOR UPDATE';
1314                 }
1315
1316                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1317                         $startOpts .= 'DISTINCT';
1318                 }
1319
1320                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1321         }
1322
1323         public function getDBname() {
1324                 return $this->dbName;
1325         }
1326
1327         public function getServer() {
1328                 return $this->server;
1329         }
1330
1331         public function buildConcat( $stringList ) {
1332                 return implode( ' || ', $stringList );
1333         }
1334
1335         public function buildGroupConcatField(
1336                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1337         ) {
1338                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1339
1340                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1341         }
1342
1343         public function buildStringCast( $field ) {
1344                 return $field . '::text';
1345         }
1346
1347         public function streamStatementEnd( &$sql, &$newLine ) {
1348                 # Allow dollar quoting for function declarations
1349                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1350                         if ( $this->delimiter ) {
1351                                 $this->delimiter = false;
1352                         } else {
1353                                 $this->delimiter = ';';
1354                         }
1355                 }
1356
1357                 return parent::streamStatementEnd( $sql, $newLine );
1358         }
1359
1360         public function doLockTables( array $read, array $write, $method ) {
1361                 $tablesWrite = [];
1362                 foreach ( $write as $table ) {
1363                         $tablesWrite[] = $this->tableName( $table );
1364                 }
1365                 $tablesRead = [];
1366                 foreach ( $read as $table ) {
1367                         $tablesRead[] = $this->tableName( $table );
1368                 }
1369
1370                 // Acquire locks for the duration of the current transaction...
1371                 if ( $tablesWrite ) {
1372                         $this->query(
1373                                 'LOCK TABLE ONLY ' . implode( ',', $tablesWrite ) . ' IN EXCLUSIVE MODE',
1374                                 $method
1375                         );
1376                 }
1377                 if ( $tablesRead ) {
1378                         $this->query(
1379                                 'LOCK TABLE ONLY ' . implode( ',', $tablesRead ) . ' IN SHARE MODE',
1380                                 $method
1381                         );
1382                 }
1383
1384                 return true;
1385         }
1386
1387         public function lockIsFree( $lockName, $method ) {
1388                 if ( !parent::lockIsFree( $lockName, $method ) ) {
1389                         return false; // already held
1390                 }
1391                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1392                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1393                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1394                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1395                 $row = $this->fetchObject( $result );
1396
1397                 return ( $row->lockstatus === 't' );
1398         }
1399
1400         public function lock( $lockName, $method, $timeout = 5 ) {
1401                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1402                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1403                 $loop = new WaitConditionLoop(
1404                         function () use ( $lockName, $key, $timeout, $method ) {
1405                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1406                                 $row = $this->fetchObject( $res );
1407                                 if ( $row->lockstatus === 't' ) {
1408                                         parent::lock( $lockName, $method, $timeout ); // record
1409                                         return true;
1410                                 }
1411
1412                                 return WaitConditionLoop::CONDITION_CONTINUE;
1413                         },
1414                         $timeout
1415                 );
1416
1417                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1418         }
1419
1420         public function unlock( $lockName, $method ) {
1421                 // http://www.postgresql.org/docs/9.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1422                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1423                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1424                 $row = $this->fetchObject( $result );
1425
1426                 if ( $row->lockstatus === 't' ) {
1427                         parent::unlock( $lockName, $method ); // record
1428                         return true;
1429                 }
1430
1431                 $this->queryLogger->debug( __METHOD__ . " failed to release lock\n" );
1432
1433                 return false;
1434         }
1435
1436         public function serverIsReadOnly() {
1437                 $res = $this->query( "SHOW default_transaction_read_only", __METHOD__ );
1438                 $row = $this->fetchObject( $res );
1439
1440                 return $row ? ( strtolower( $row->default_transaction_read_only ) === 'on' ) : false;
1441         }
1442
1443         /**
1444          * @param string $lockName
1445          * @return string Integer
1446          */
1447         private function bigintFromLockName( $lockName ) {
1448                 return \Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1449         }
1450 }
1451
1452 /**
1453  * @deprecated since 1.29
1454  */
1455 class_alias( DatabasePostgres::class, 'DatabasePostgres' );