includes/db/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
  24 class PostgresField implements Field {
  25         private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname,
  26                 $has_default, $default;
  27
  28         /**
  29          * @param IDatabase $db
  30          * @param string $table
  31          * @param string $field
  32          * @return null|PostgresField
  33          */
  34         static function fromText( $db, $table, $field ) {
  35                 $q = <<<SQL
  36 SELECT
  37  attnotnull, attlen, conname AS conname,
  38  atthasdef,
  39  adsrc,
  40  COALESCE(condeferred, 'f') AS deferred,
  41  COALESCE(condeferrable, 'f') AS deferrable,
  42  CASE WHEN typname = 'int2' THEN 'smallint'
  43   WHEN typname = 'int4' THEN 'integer'
  44   WHEN typname = 'int8' THEN 'bigint'
  45   WHEN typname = 'bpchar' THEN 'char'
  46  ELSE typname END AS typname
  47 FROM pg_class c
  48 JOIN pg_namespace n ON (n.oid = c.relnamespace)
  49 JOIN pg_attribute a ON (a.attrelid = c.oid)
  50 JOIN pg_type t ON (t.oid = a.atttypid)
  51 LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
  52 LEFT JOIN pg_attrdef d on c.oid=d.adrelid and a.attnum=d.adnum
  53 WHERE relkind = 'r'
  54 AND nspname=%s
  55 AND relname=%s
  56 AND attname=%s;
  57 SQL;
  58
  59                 $table = $db->tableName( $table, 'raw' );
  60                 $res = $db->query(
  61                         sprintf( $q,
  62                                 $db->addQuotes( $db->getCoreSchema() ),
  63                                 $db->addQuotes( $table ),
  64                                 $db->addQuotes( $field )
  65                         )
  66                 );
  67                 $row = $db->fetchObject( $res );
  68                 if ( !$row ) {
  69                         return null;
  70                 }
  71                 $n = new PostgresField;
  72                 $n->type = $row->typname;
  73                 $n->nullable = ( $row->attnotnull == 'f' );
  74                 $n->name = $field;
  75                 $n->tablename = $table;
  76                 $n->max_length = $row->attlen;
  77                 $n->deferrable = ( $row->deferrable == 't' );
  78                 $n->deferred = ( $row->deferred == 't' );
  79                 $n->conname = $row->conname;
  80                 $n->has_default = ( $row->atthasdef === 't' );
  81                 $n->default = $row->adsrc;
  82
  83                 return $n;
  84         }
  85
  86         function name() {
  87                 return $this->name;
  88         }
  89
  90         function tableName() {
  91                 return $this->tablename;
  92         }
  93
  94         function type() {
  95                 return $this->type;
  96         }
  97
  98         function isNullable() {
  99                 return $this->nullable;
 100         }
 101
 102         function maxLength() {
 103                 return $this->max_length;
 104         }
 105
 106         function is_deferrable() {
 107                 return $this->deferrable;
 108         }
 109
 110         function is_deferred() {
 111                 return $this->deferred;
 112         }
 113
 114         function conname() {
 115                 return $this->conname;
 116         }
 117
 118         /**
 119          * @since 1.19
 120          * @return bool|mixed
 121          */
 122         function defaultValue() {
 123                 if ( $this->has_default ) {
 124                         return $this->default;
 125                 } else {
 126                         return false;
 127                 }
 128         }
 129 }
 130
 131 /**
 132  * Manage savepoints within a transaction
 133  * @ingroup Database
 134  * @since 1.19
 135  */
 136 class SavepointPostgres {
 137         /** @var DatabasePostgres Establish a savepoint within a transaction */
 138         protected $dbw;
 139         protected $id;
 140         protected $didbegin;
 141
 142         /**
 143          * @param IDatabase $dbw
 144          * @param int $id
 145          */
 146         public function __construct( $dbw, $id ) {
 147                 $this->dbw = $dbw;
 148                 $this->id = $id;
 149                 $this->didbegin = false;
 150                 /* If we are not in a transaction, we need to be for savepoint trickery */
 151                 if ( !$dbw->trxLevel() ) {
 152                         $dbw->begin( "FOR SAVEPOINT", DatabasePostgres::TRANSACTION_INTERNAL );
 153                         $this->didbegin = true;
 154                 }
 155         }
 156
 157         public function __destruct() {
 158                 if ( $this->didbegin ) {
 159                         $this->dbw->rollback();
 160                         $this->didbegin = false;
 161                 }
 162         }
 163
 164         public function commit() {
 165                 if ( $this->didbegin ) {
 166                         $this->dbw->commit();
 167                         $this->didbegin = false;
 168                 }
 169         }
 170
 171         protected function query( $keyword, $msg_ok, $msg_failed ) {
 172                 if ( $this->dbw->doQuery( $keyword . " " . $this->id ) !== false ) {
 173                 } else {
 174                         wfDebug( sprintf( $msg_failed, $this->id ) );
 175                 }
 176         }
 177
 178         public function savepoint() {
 179                 $this->query( "SAVEPOINT",
 180                         "Transaction state: savepoint \"%s\" established.\n",
 181                         "Transaction state: establishment of savepoint \"%s\" FAILED.\n"
 182                 );
 183         }
 184
 185         public function release() {
 186                 $this->query( "RELEASE",
 187                         "Transaction state: savepoint \"%s\" released.\n",
 188                         "Transaction state: release of savepoint \"%s\" FAILED.\n"
 189                 );
 190         }
 191
 192         public function rollback() {
 193                 $this->query( "ROLLBACK TO",
 194                         "Transaction state: savepoint \"%s\" rolled back.\n",
 195                         "Transaction state: rollback of savepoint \"%s\" FAILED.\n"
 196                 );
 197         }
 198
 199         public function __toString() {
 200                 return (string)$this->id;
 201         }
 202 }
 203
 204 /**
 205  * @ingroup Database
 206  */
 207 class DatabasePostgres extends DatabaseBase {
 208         /** @var resource */
 209         protected $mLastResult = null;
 210
 211         /** @var int The number of rows affected as an integer */
 212         protected $mAffectedRows = null;
 213
 214         /** @var int */
 215         private $mInsertId = null;
 216
 217         /** @var float|string */
 218         private $numericVersion = null;
 219
 220         /** @var string Connect string to open a PostgreSQL connection */
 221         private $connectString;
 222
 223         /** @var string */
 224         private $mCoreSchema;
 225
 226         function getType() {
 227                 return 'postgres';
 228         }
 229
 230         function cascadingDeletes() {
 231                 return true;
 232         }
 233
 234         function cleanupTriggers() {
 235                 return true;
 236         }
 237
 238         function strictIPs() {
 239                 return true;
 240         }
 241
 242         function implicitGroupby() {
 243                 return false;
 244         }
 245
 246         function implicitOrderby() {
 247                 return false;
 248         }
 249
 250         function hasConstraint( $name ) {
 251                 $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
 252                         "WHERE c.connamespace = n.oid AND conname = '" .
 253                         pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" .
 254                         pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 255                 $res = $this->doQuery( $sql );
 256
 257                 return $this->numRows( $res );
 258         }
 259
 260         /**
 261          * Usually aborts on failure
 262          * @param string $server
 263          * @param string $user
 264          * @param string $password
 265          * @param string $dbName
 266          * @throws DBConnectionError|Exception
 267          * @return resource|bool|null
 268          */
 269         function open( $server, $user, $password, $dbName ) {
 270                 # Test for Postgres support, to avoid suppressed fatal error
 271                 if ( !function_exists( 'pg_connect' ) ) {
 272                         throw new DBConnectionError(
 273                                 $this,
 274                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
 275                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
 276                                 "webserver and database)\n"
 277                         );
 278                 }
 279
 280                 global $wgDBport;
 281
 282                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 283                         return null;
 284                 }
 285
 286                 $this->mServer = $server;
 287                 $port = $wgDBport;
 288                 $this->mUser = $user;
 289                 $this->mPassword = $password;
 290                 $this->mDBname = $dbName;
 291
 292                 $connectVars = [
 293                         'dbname' => $dbName,
 294                         'user' => $user,
 295                         'password' => $password
 296                 ];
 297                 if ( $server != false && $server != '' ) {
 298                         $connectVars['host'] = $server;
 299                 }
 300                 if ( $port != false && $port != '' ) {
 301                         $connectVars['port'] = $port;
 302                 }
 303                 if ( $this->mFlags & DBO_SSL ) {
 304                         $connectVars['sslmode'] = 1;
 305                 }
 306
 307                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 308                 $this->close();
 309                 $this->installErrorHandler();
 310
 311                 try {
 312                         $this->mConn = pg_connect( $this->connectString );
 313                 } catch ( Exception $ex ) {
 314                         $this->restoreErrorHandler();
 315                         throw $ex;
 316                 }
 317
 318                 $phpError = $this->restoreErrorHandler();
 319
 320                 if ( !$this->mConn ) {
 321                         wfDebug( "DB connection error\n" );
 322                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " .
 323                                 substr( $password, 0, 3 ) . "...\n" );
 324                         wfDebug( $this->lastError() . "\n" );
 325                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 326                 }
 327
 328                 $this->mOpened = true;
 329
 330                 global $wgCommandLineMode;
 331                 # If called from the command-line (e.g. importDump), only show errors
 332                 if ( $wgCommandLineMode ) {
 333                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 334                 }
 335
 336                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 337                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 338                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 339                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 340                 if ( $this->getServerVersion() >= 9.0 ) {
 341                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 342                 }
 343
 344                 global $wgDBmwschema;
 345                 $this->determineCoreSchema( $wgDBmwschema );
 346
 347                 return $this->mConn;
 348         }
 349
 350         /**
 351          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 352          * DB name doesn't match the open connection, open a new one
 353          * @param string $db
 354          * @return bool
 355          */
 356         function selectDB( $db ) {
 357                 if ( $this->mDBname !== $db ) {
 358                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 359                 } else {
 360                         return true;
 361                 }
 362         }
 363
 364         function makeConnectionString( $vars ) {
 365                 $s = '';
 366                 foreach ( $vars as $name => $value ) {
 367                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 368                 }
 369
 370                 return $s;
 371         }
 372
 373         /**
 374          * Closes a database connection, if it is open
 375          * Returns success, true if already closed
 376          * @return bool
 377          */
 378         protected function closeConnection() {
 379                 return pg_close( $this->mConn );
 380         }
 381
 382         public function doQuery( $sql ) {
 383                 $sql = mb_convert_encoding( $sql, 'UTF-8' );
 384                 // Clear previously left over PQresult
 385                 while ( $res = pg_get_result( $this->mConn ) ) {
 386                         pg_free_result( $res );
 387                 }
 388                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 389                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 390                 }
 391                 $this->mLastResult = pg_get_result( $this->mConn );
 392                 $this->mAffectedRows = null;
 393                 if ( pg_result_error( $this->mLastResult ) ) {
 394                         return false;
 395                 }
 396
 397                 return $this->mLastResult;
 398         }
 399
 400         protected function dumpError() {
 401                 $diags = [
 402                         PGSQL_DIAG_SEVERITY,
 403                         PGSQL_DIAG_SQLSTATE,
 404                         PGSQL_DIAG_MESSAGE_PRIMARY,
 405                         PGSQL_DIAG_MESSAGE_DETAIL,
 406                         PGSQL_DIAG_MESSAGE_HINT,
 407                         PGSQL_DIAG_STATEMENT_POSITION,
 408                         PGSQL_DIAG_INTERNAL_POSITION,
 409                         PGSQL_DIAG_INTERNAL_QUERY,
 410                         PGSQL_DIAG_CONTEXT,
 411                         PGSQL_DIAG_SOURCE_FILE,
 412                         PGSQL_DIAG_SOURCE_LINE,
 413                         PGSQL_DIAG_SOURCE_FUNCTION
 414                 ];
 415                 foreach ( $diags as $d ) {
 416                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n",
 417                                 $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 418                 }
 419         }
 420
 421         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 422                 if ( $tempIgnore ) {
 423                         /* Check for constraint violation */
 424                         if ( $errno === '23505' ) {
 425                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 426
 427                                 return;
 428                         }
 429                 }
 430                 /* Transaction stays in the ERROR state until rolled back */
 431                 if ( $this->mTrxLevel ) {
 432                         $ignore = $this->ignoreErrors( true );
 433                         $this->rollback( __METHOD__ );
 434                         $this->ignoreErrors( $ignore );
 435                 }
 436                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 437         }
 438
 439         function queryIgnore( $sql, $fname = __METHOD__ ) {
 440                 return $this->query( $sql, $fname, true );
 441         }
 442
 443         /**
 444          * @param stdClass|ResultWrapper $res
 445          * @throws DBUnexpectedError
 446          */
 447         function freeResult( $res ) {
 448                 if ( $res instanceof ResultWrapper ) {
 449                         $res = $res->result;
 450                 }
 451                 MediaWiki\suppressWarnings();
 452                 $ok = pg_free_result( $res );
 453                 MediaWiki\restoreWarnings();
 454                 if ( !$ok ) {
 455                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 456                 }
 457         }
 458
 459         /**
 460          * @param ResultWrapper|stdClass $res
 461          * @return stdClass
 462          * @throws DBUnexpectedError
 463          */
 464         function fetchObject( $res ) {
 465                 if ( $res instanceof ResultWrapper ) {
 466                         $res = $res->result;
 467                 }
 468                 MediaWiki\suppressWarnings();
 469                 $row = pg_fetch_object( $res );
 470                 MediaWiki\restoreWarnings();
 471                 # @todo FIXME: HACK HACK HACK HACK debug
 472
 473                 # @todo hashar: not sure if the following test really trigger if the object
 474                 #          fetching failed.
 475                 if ( pg_last_error( $this->mConn ) ) {
 476                         throw new DBUnexpectedError(
 477                                 $this,
 478                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 479                         );
 480                 }
 481
 482                 return $row;
 483         }
 484
 485         function fetchRow( $res ) {
 486                 if ( $res instanceof ResultWrapper ) {
 487                         $res = $res->result;
 488                 }
 489                 MediaWiki\suppressWarnings();
 490                 $row = pg_fetch_array( $res );
 491                 MediaWiki\restoreWarnings();
 492                 if ( pg_last_error( $this->mConn ) ) {
 493                         throw new DBUnexpectedError(
 494                                 $this,
 495                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 496                         );
 497                 }
 498
 499                 return $row;
 500         }
 501
 502         function numRows( $res ) {
 503                 if ( $res instanceof ResultWrapper ) {
 504                         $res = $res->result;
 505                 }
 506                 MediaWiki\suppressWarnings();
 507                 $n = pg_num_rows( $res );
 508                 MediaWiki\restoreWarnings();
 509                 if ( pg_last_error( $this->mConn ) ) {
 510                         throw new DBUnexpectedError(
 511                                 $this,
 512                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 513                         );
 514                 }
 515
 516                 return $n;
 517         }
 518
 519         function numFields( $res ) {
 520                 if ( $res instanceof ResultWrapper ) {
 521                         $res = $res->result;
 522                 }
 523
 524                 return pg_num_fields( $res );
 525         }
 526
 527         function fieldName( $res, $n ) {
 528                 if ( $res instanceof ResultWrapper ) {
 529                         $res = $res->result;
 530                 }
 531
 532                 return pg_field_name( $res, $n );
 533         }
 534
 535         /**
 536          * Return the result of the last call to nextSequenceValue();
 537          * This must be called after nextSequenceValue().
 538          *
 539          * @return int|null
 540          */
 541         function insertId() {
 542                 return $this->mInsertId;
 543         }
 544
 545         /**
 546          * @param mixed $res
 547          * @param int $row
 548          * @return bool
 549          */
 550         function dataSeek( $res, $row ) {
 551                 if ( $res instanceof ResultWrapper ) {
 552                         $res = $res->result;
 553                 }
 554
 555                 return pg_result_seek( $res, $row );
 556         }
 557
 558         function lastError() {
 559                 if ( $this->mConn ) {
 560                         if ( $this->mLastResult ) {
 561                                 return pg_result_error( $this->mLastResult );
 562                         } else {
 563                                 return pg_last_error();
 564                         }
 565                 } else {
 566                         return 'No database connection';
 567                 }
 568         }
 569
 570         function lastErrno() {
 571                 if ( $this->mLastResult ) {
 572                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 573                 } else {
 574                         return false;
 575                 }
 576         }
 577
 578         function affectedRows() {
 579                 if ( !is_null( $this->mAffectedRows ) ) {
 580                         // Forced result for simulated queries
 581                         return $this->mAffectedRows;
 582                 }
 583                 if ( empty( $this->mLastResult ) ) {
 584                         return 0;
 585                 }
 586
 587                 return pg_affected_rows( $this->mLastResult );
 588         }
 589
 590         /**
 591          * Estimate rows in dataset
 592          * Returns estimated count, based on EXPLAIN output
 593          * This is not necessarily an accurate estimate, so use sparingly
 594          * Returns -1 if count cannot be found
 595          * Takes same arguments as Database::select()
 596          *
 597          * @param string $table
 598          * @param string $vars
 599          * @param string $conds
 600          * @param string $fname
 601          * @param array $options
 602          * @return int
 603          */
 604         function estimateRowCount( $table, $vars = '*', $conds = '',
 605                 $fname = __METHOD__, $options = []
 606         ) {
 607                 $options['EXPLAIN'] = true;
 608                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 609                 $rows = -1;
 610                 if ( $res ) {
 611                         $row = $this->fetchRow( $res );
 612                         $count = [];
 613                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 614                                 $rows = (int)$count[1];
 615                         }
 616                 }
 617
 618                 return $rows;
 619         }
 620
 621         /**
 622          * Returns information about an index
 623          * If errors are explicitly ignored, returns NULL on failure
 624          *
 625          * @param string $table
 626          * @param string $index
 627          * @param string $fname
 628          * @return bool|null
 629          */
 630         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 631                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 632                 $res = $this->query( $sql, $fname );
 633                 if ( !$res ) {
 634                         return null;
 635                 }
 636                 foreach ( $res as $row ) {
 637                         if ( $row->indexname == $this->indexName( $index ) ) {
 638                                 return $row;
 639                         }
 640                 }
 641
 642                 return false;
 643         }
 644
 645         /**
 646          * Returns is of attributes used in index
 647          *
 648          * @since 1.19
 649          * @param string $index
 650          * @param bool|string $schema
 651          * @return array
 652          */
 653         function indexAttributes( $index, $schema = false ) {
 654                 if ( $schema === false ) {
 655                         $schema = $this->getCoreSchema();
 656                 }
 657                 /*
 658                  * A subquery would be not needed if we didn't care about the order
 659                  * of attributes, but we do
 660                  */
 661                 $sql = <<<__INDEXATTR__
 662
 663                         SELECT opcname,
 664                                 attname,
 665                                 i.indoption[s.g] as option,
 666                                 pg_am.amname
 667                         FROM
 668                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 669                                         FROM
 670                                                 pg_index isub
 671                                         JOIN pg_class cis
 672                                                 ON cis.oid=isub.indexrelid
 673                                         JOIN pg_namespace ns
 674                                                 ON cis.relnamespace = ns.oid
 675                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 676                                 pg_attribute,
 677                                 pg_opclass opcls,
 678                                 pg_am,
 679                                 pg_class ci
 680                                 JOIN pg_index i
 681                                         ON ci.oid=i.indexrelid
 682                                 JOIN pg_class ct
 683                                         ON ct.oid = i.indrelid
 684                                 JOIN pg_namespace n
 685                                         ON ci.relnamespace = n.oid
 686                                 WHERE
 687                                         ci.relname='$index' AND n.nspname='$schema'
 688                                         AND     attrelid = ct.oid
 689                                         AND     i.indkey[s.g] = attnum
 690                                         AND     i.indclass[s.g] = opcls.oid
 691                                         AND     pg_am.oid = opcls.opcmethod
 692 __INDEXATTR__;
 693                 $res = $this->query( $sql, __METHOD__ );
 694                 $a = [];
 695                 if ( $res ) {
 696                         foreach ( $res as $row ) {
 697                                 $a[] = [
 698                                         $row->attname,
 699                                         $row->opcname,
 700                                         $row->amname,
 701                                         $row->option ];
 702                         }
 703                 } else {
 704                         return null;
 705                 }
 706
 707                 return $a;
 708         }
 709
 710         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 711                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 712                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 713                         $this->strencode( $this->indexName( $index ) ) .
 714                         ")'";
 715                 $res = $this->query( $sql, $fname );
 716                 if ( !$res ) {
 717                         return null;
 718                 }
 719
 720                 return $res->numRows() > 0;
 721         }
 722
 723         /**
 724          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 725          * to the parent function to get the actual SQL text.
 726          *
 727          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 728          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 729          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 730          *
 731          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 732          * @see DatabaseBase::selectSQLText
 733          */
 734         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 735                 $options = [], $join_conds = []
 736         ) {
 737                 if ( is_array( $options ) ) {
 738                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 739                         if ( $forUpdateKey !== false && $join_conds ) {
 740                                 unset( $options[$forUpdateKey] );
 741
 742                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 743                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 744                                                 $options['FOR UPDATE'][] = $table_cond;
 745                                         }
 746                                 }
 747                         }
 748
 749                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 750                                 unset( $options['ORDER BY'] );
 751                         }
 752                 }
 753
 754                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 755         }
 756
 757         /**
 758          * INSERT wrapper, inserts an array into a table
 759          *
 760          * $args may be a single associative array, or an array of these with numeric keys,
 761          * for multi-row insert (Postgres version 8.2 and above only).
 762          *
 763          * @param string $table Name of the table to insert to.
 764          * @param array $args Items to insert into the table.
 765          * @param string $fname Name of the function, for profiling
 766          * @param array|string $options String or array. Valid options: IGNORE
 767          * @return bool Success of insert operation. IGNORE always returns true.
 768          */
 769         function insert( $table, $args, $fname = __METHOD__, $options = [] ) {
 770                 if ( !count( $args ) ) {
 771                         return true;
 772                 }
 773
 774                 $table = $this->tableName( $table );
 775                 if ( !isset( $this->numericVersion ) ) {
 776                         $this->getServerVersion();
 777                 }
 778
 779                 if ( !is_array( $options ) ) {
 780                         $options = [ $options ];
 781                 }
 782
 783                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 784                         $multi = true;
 785                         $keys = array_keys( $args[0] );
 786                 } else {
 787                         $multi = false;
 788                         $keys = array_keys( $args );
 789                 }
 790
 791                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 792                 $savepoint = null;
 793                 if ( in_array( 'IGNORE', $options ) ) {
 794                         $savepoint = new SavepointPostgres( $this, 'mw' );
 795                         $olde = error_reporting( 0 );
 796                         // For future use, we may want to track the number of actual inserts
 797                         // Right now, insert (all writes) simply return true/false
 798                         $numrowsinserted = 0;
 799                 }
 800
 801                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 802
 803                 if ( $multi ) {
 804                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 805                                 $first = true;
 806                                 foreach ( $args as $row ) {
 807                                         if ( $first ) {
 808                                                 $first = false;
 809                                         } else {
 810                                                 $sql .= ',';
 811                                         }
 812                                         $sql .= '(' . $this->makeList( $row ) . ')';
 813                                 }
 814                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 815                         } else {
 816                                 $res = true;
 817                                 $origsql = $sql;
 818                                 foreach ( $args as $row ) {
 819                                         $tempsql = $origsql;
 820                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 821
 822                                         if ( $savepoint ) {
 823                                                 $savepoint->savepoint();
 824                                         }
 825
 826                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 827
 828                                         if ( $savepoint ) {
 829                                                 $bar = pg_result_error( $this->mLastResult );
 830                                                 if ( $bar != false ) {
 831                                                         $savepoint->rollback();
 832                                                 } else {
 833                                                         $savepoint->release();
 834                                                         $numrowsinserted++;
 835                                                 }
 836                                         }
 837
 838                                         // If any of them fail, we fail overall for this function call
 839                                         // Note that this will be ignored if IGNORE is set
 840                                         if ( !$tempres ) {
 841                                                 $res = false;
 842                                         }
 843                                 }
 844                         }
 845                 } else {
 846                         // Not multi, just a lone insert
 847                         if ( $savepoint ) {
 848                                 $savepoint->savepoint();
 849                         }
 850
 851                         $sql .= '(' . $this->makeList( $args ) . ')';
 852                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 853                         if ( $savepoint ) {
 854                                 $bar = pg_result_error( $this->mLastResult );
 855                                 if ( $bar != false ) {
 856                                         $savepoint->rollback();
 857                                 } else {
 858                                         $savepoint->release();
 859                                         $numrowsinserted++;
 860                                 }
 861                         }
 862                 }
 863                 if ( $savepoint ) {
 864                         error_reporting( $olde );
 865                         $savepoint->commit();
 866
 867                         // Set the affected row count for the whole operation
 868                         $this->mAffectedRows = $numrowsinserted;
 869
 870                         // IGNORE always returns true
 871                         return true;
 872                 }
 873
 874                 return $res;
 875         }
 876
 877         /**
 878          * INSERT SELECT wrapper
 879          * $varMap must be an associative array of the form [ 'dest1' => 'source1', ... ]
 880          * Source items may be literals rather then field names, but strings should
 881          * be quoted with Database::addQuotes()
 882          * $conds may be "*" to copy the whole table
 883          * srcTable may be an array of tables.
 884          * @todo FIXME: Implement this a little better (seperate select/insert)?
 885          *
 886          * @param string $destTable
 887          * @param array|string $srcTable
 888          * @param array $varMap
 889          * @param array $conds
 890          * @param string $fname
 891          * @param array $insertOptions
 892          * @param array $selectOptions
 893          * @return bool
 894          */
 895         function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 896                 $insertOptions = [], $selectOptions = [] ) {
 897                 $destTable = $this->tableName( $destTable );
 898
 899                 if ( !is_array( $insertOptions ) ) {
 900                         $insertOptions = [ $insertOptions ];
 901                 }
 902
 903                 /*
 904                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
 905                  * Ignore LOW PRIORITY option, since it is MySQL-specific
 906                  */
 907                 $savepoint = null;
 908                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 909                         $savepoint = new SavepointPostgres( $this, 'mw' );
 910                         $olde = error_reporting( 0 );
 911                         $numrowsinserted = 0;
 912                         $savepoint->savepoint();
 913                 }
 914
 915                 if ( !is_array( $selectOptions ) ) {
 916                         $selectOptions = [ $selectOptions ];
 917                 }
 918                 list( $startOpts, $useIndex, $tailOpts, $ignoreIndex ) =
 919                         $this->makeSelectOptions( $selectOptions );
 920                 if ( is_array( $srcTable ) ) {
 921                         $srcTable = implode( ',', array_map( [ &$this, 'tableName' ], $srcTable ) );
 922                 } else {
 923                         $srcTable = $this->tableName( $srcTable );
 924                 }
 925
 926                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 927                         " SELECT $startOpts " . implode( ',', $varMap ) .
 928                         " FROM $srcTable $useIndex $ignoreIndex ";
 929
 930                 if ( $conds != '*' ) {
 931                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 932                 }
 933
 934                 $sql .= " $tailOpts";
 935
 936                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 937                 if ( $savepoint ) {
 938                         $bar = pg_result_error( $this->mLastResult );
 939                         if ( $bar != false ) {
 940                                 $savepoint->rollback();
 941                         } else {
 942                                 $savepoint->release();
 943                                 $numrowsinserted++;
 944                         }
 945                         error_reporting( $olde );
 946                         $savepoint->commit();
 947
 948                         // Set the affected row count for the whole operation
 949                         $this->mAffectedRows = $numrowsinserted;
 950
 951                         // IGNORE always returns true
 952                         return true;
 953                 }
 954
 955                 return $res;
 956         }
 957
 958         function tableName( $name, $format = 'quoted' ) {
 959                 # Replace reserved words with better ones
 960                 switch ( $name ) {
 961                         case 'user':
 962                                 return $this->realTableName( 'mwuser', $format );
 963                         case 'text':
 964                                 return $this->realTableName( 'pagecontent', $format );
 965                         default:
 966                                 return $this->realTableName( $name, $format );
 967                 }
 968         }
 969
 970         /* Don't cheat on installer */
 971         function realTableName( $name, $format = 'quoted' ) {
 972                 return parent::tableName( $name, $format );
 973         }
 974
 975         /**
 976          * Return the next in a sequence, save the value for retrieval via insertId()
 977          *
 978          * @param string $seqName
 979          * @return int|null
 980          */
 981         function nextSequenceValue( $seqName ) {
 982                 $safeseq = str_replace( "'", "''", $seqName );
 983                 $res = $this->query( "SELECT nextval('$safeseq')" );
 984                 $row = $this->fetchRow( $res );
 985                 $this->mInsertId = $row[0];
 986
 987                 return $this->mInsertId;
 988         }
 989
 990         /**
 991          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 992          *
 993          * @param string $seqName
 994          * @return int
 995          */
 996         function currentSequenceValue( $seqName ) {
 997                 $safeseq = str_replace( "'", "''", $seqName );
 998                 $res = $this->query( "SELECT currval('$safeseq')" );
 999                 $row = $this->fetchRow( $res );
1000                 $currval = $row[0];
1001
1002                 return $currval;
1003         }
1004
1005         # Returns the size of a text field, or -1 for "unlimited"
1006         function textFieldSize( $table, $field ) {
1007                 $table = $this->tableName( $table );
1008                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1009                         FROM pg_class c, pg_attribute a, pg_type t
1010                         WHERE relname='$table' AND a.attrelid=c.oid AND
1011                                 a.atttypid=t.oid and a.attname='$field'";
1012                 $res = $this->query( $sql );
1013                 $row = $this->fetchObject( $res );
1014                 if ( $row->ftype == 'varchar' ) {
1015                         $size = $row->size - 4;
1016                 } else {
1017                         $size = $row->size;
1018                 }
1019
1020                 return $size;
1021         }
1022
1023         function limitResult( $sql, $limit, $offset = false ) {
1024                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1025         }
1026
1027         function wasDeadlock() {
1028                 return $this->lastErrno() == '40P01';
1029         }
1030
1031         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1032                 $newName = $this->addIdentifierQuotes( $newName );
1033                 $oldName = $this->addIdentifierQuotes( $oldName );
1034
1035                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1036                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1037         }
1038
1039         function listTables( $prefix = null, $fname = __METHOD__ ) {
1040                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1041                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1042                 $endArray = [];
1043
1044                 foreach ( $result as $table ) {
1045                         $vars = get_object_vars( $table );
1046                         $table = array_pop( $vars );
1047                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1048                                 $endArray[] = $table;
1049                         }
1050                 }
1051
1052                 return $endArray;
1053         }
1054
1055         function timestamp( $ts = 0 ) {
1056                 return wfTimestamp( TS_POSTGRES, $ts );
1057         }
1058
1059         /**
1060          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1061          * to http://www.php.net/manual/en/ref.pgsql.php
1062          *
1063          * Parsing a postgres array can be a tricky problem, he's my
1064          * take on this, it handles multi-dimensional arrays plus
1065          * escaping using a nasty regexp to determine the limits of each
1066          * data-item.
1067          *
1068          * This should really be handled by PHP PostgreSQL module
1069          *
1070          * @since 1.19
1071          * @param string $text Postgreql array returned in a text form like {a,b}
1072          * @param string $output
1073          * @param int $limit
1074          * @param int $offset
1075          * @return string
1076          */
1077         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1078                 if ( false === $limit ) {
1079                         $limit = strlen( $text ) - 1;
1080                         $output = [];
1081                 }
1082                 if ( '{}' == $text ) {
1083                         return $output;
1084                 }
1085                 do {
1086                         if ( '{' != $text[$offset] ) {
1087                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1088                                         $text, $match, 0, $offset );
1089                                 $offset += strlen( $match[0] );
1090                                 $output[] = ( '"' != $match[1][0]
1091                                         ? $match[1]
1092                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1093                                 if ( '},' == $match[3] ) {
1094                                         return $output;
1095                                 }
1096                         } else {
1097                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1098                         }
1099                 } while ( $limit > $offset );
1100
1101                 return $output;
1102         }
1103
1104         /**
1105          * Return aggregated value function call
1106          * @param array $valuedata
1107          * @param string $valuename
1108          * @return array
1109          */
1110         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1111                 return $valuedata;
1112         }
1113
1114         /**
1115          * @return string Wikitext of a link to the server software's web site
1116          */
1117         public function getSoftwareLink() {
1118                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1119         }
1120
1121         /**
1122          * Return current schema (executes SELECT current_schema())
1123          * Needs transaction
1124          *
1125          * @since 1.19
1126          * @return string Default schema for the current session
1127          */
1128         function getCurrentSchema() {
1129                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1130                 $row = $this->fetchRow( $res );
1131
1132                 return $row[0];
1133         }
1134
1135         /**
1136          * Return list of schemas which are accessible without schema name
1137          * This is list does not contain magic keywords like "$user"
1138          * Needs transaction
1139          *
1140          * @see getSearchPath()
1141          * @see setSearchPath()
1142          * @since 1.19
1143          * @return array List of actual schemas for the current sesson
1144          */
1145         function getSchemas() {
1146                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1147                 $row = $this->fetchRow( $res );
1148                 $schemas = [];
1149
1150                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1151
1152                 return $this->pg_array_parse( $row[0], $schemas );
1153         }
1154
1155         /**
1156          * Return search patch for schemas
1157          * This is different from getSchemas() since it contain magic keywords
1158          * (like "$user").
1159          * Needs transaction
1160          *
1161          * @since 1.19
1162          * @return array How to search for table names schemas for the current user
1163          */
1164         function getSearchPath() {
1165                 $res = $this->query( "SHOW search_path", __METHOD__ );
1166                 $row = $this->fetchRow( $res );
1167
1168                 /* PostgreSQL returns SHOW values as strings */
1169
1170                 return explode( ",", $row[0] );
1171         }
1172
1173         /**
1174          * Update search_path, values should already be sanitized
1175          * Values may contain magic keywords like "$user"
1176          * @since 1.19
1177          *
1178          * @param array $search_path List of schemas to be searched by default
1179          */
1180         function setSearchPath( $search_path ) {
1181                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1182         }
1183
1184         /**
1185          * Determine default schema for MediaWiki core
1186          * Adjust this session schema search path if desired schema exists
1187          * and is not alread there.
1188          *
1189          * We need to have name of the core schema stored to be able
1190          * to query database metadata.
1191          *
1192          * This will be also called by the installer after the schema is created
1193          *
1194          * @since 1.19
1195          *
1196          * @param string $desiredSchema
1197          */
1198         function determineCoreSchema( $desiredSchema ) {
1199                 $this->begin( __METHOD__, self::TRANSACTION_INTERNAL );
1200                 if ( $this->schemaExists( $desiredSchema ) ) {
1201                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1202                                 $this->mCoreSchema = $desiredSchema;
1203                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1204                         } else {
1205                                 /**
1206                                  * Prepend our schema (e.g. 'mediawiki') in front
1207                                  * of the search path
1208                                  * Fixes bug 15816
1209                                  */
1210                                 $search_path = $this->getSearchPath();
1211                                 array_unshift( $search_path,
1212                                         $this->addIdentifierQuotes( $desiredSchema ) );
1213                                 $this->setSearchPath( $search_path );
1214                                 $this->mCoreSchema = $desiredSchema;
1215                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1216                         }
1217                 } else {
1218                         $this->mCoreSchema = $this->getCurrentSchema();
1219                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1220                                 $this->mCoreSchema . "\"\n" );
1221                 }
1222                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1223                 $this->commit( __METHOD__ );
1224         }
1225
1226         /**
1227          * Return schema name fore core MediaWiki tables
1228          *
1229          * @since 1.19
1230          * @return string Core schema name
1231          */
1232         function getCoreSchema() {
1233                 return $this->mCoreSchema;
1234         }
1235
1236         /**
1237          * @return string Version information from the database
1238          */
1239         function getServerVersion() {
1240                 if ( !isset( $this->numericVersion ) ) {
1241                         $versionInfo = pg_version( $this->mConn );
1242                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1243                                 // Old client, abort install
1244                                 $this->numericVersion = '7.3 or earlier';
1245                         } elseif ( isset( $versionInfo['server'] ) ) {
1246                                 // Normal client
1247                                 $this->numericVersion = $versionInfo['server'];
1248                         } else {
1249                                 // Bug 16937: broken pgsql extension from PHP<5.3
1250                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1251                         }
1252                 }
1253
1254                 return $this->numericVersion;
1255         }
1256
1257         /**
1258          * Query whether a given relation exists (in the given schema, or the
1259          * default mw one if not given)
1260          * @param string $table
1261          * @param array|string $types
1262          * @param bool|string $schema
1263          * @return bool
1264          */
1265         function relationExists( $table, $types, $schema = false ) {
1266                 if ( !is_array( $types ) ) {
1267                         $types = [ $types ];
1268                 }
1269                 if ( !$schema ) {
1270                         $schema = $this->getCoreSchema();
1271                 }
1272                 $table = $this->realTableName( $table, 'raw' );
1273                 $etable = $this->addQuotes( $table );
1274                 $eschema = $this->addQuotes( $schema );
1275                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1276                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1277                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1278                 $res = $this->query( $sql );
1279                 $count = $res ? $res->numRows() : 0;
1280
1281                 return (bool)$count;
1282         }
1283
1284         /**
1285          * For backward compatibility, this function checks both tables and
1286          * views.
1287          * @param string $table
1288          * @param string $fname
1289          * @param bool|string $schema
1290          * @return bool
1291          */
1292         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1293                 return $this->relationExists( $table, [ 'r', 'v' ], $schema );
1294         }
1295
1296         function sequenceExists( $sequence, $schema = false ) {
1297                 return $this->relationExists( $sequence, 'S', $schema );
1298         }
1299
1300         function triggerExists( $table, $trigger ) {
1301                 $q = <<<SQL
1302         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1303                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1304                           AND tgrelid=pg_class.oid
1305                           AND nspname=%s AND relname=%s AND tgname=%s
1306 SQL;
1307                 $res = $this->query(
1308                         sprintf(
1309                                 $q,
1310                                 $this->addQuotes( $this->getCoreSchema() ),
1311                                 $this->addQuotes( $table ),
1312                                 $this->addQuotes( $trigger )
1313                         )
1314                 );
1315                 if ( !$res ) {
1316                         return null;
1317                 }
1318                 $rows = $res->numRows();
1319
1320                 return $rows;
1321         }
1322
1323         function ruleExists( $table, $rule ) {
1324                 $exists = $this->selectField( 'pg_rules', 'rulename',
1325                         [
1326                                 'rulename' => $rule,
1327                                 'tablename' => $table,
1328                                 'schemaname' => $this->getCoreSchema()
1329                         ]
1330                 );
1331
1332                 return $exists === $rule;
1333         }
1334
1335         function constraintExists( $table, $constraint ) {
1336                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1337                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1338                         $this->addQuotes( $this->getCoreSchema() ),
1339                         $this->addQuotes( $table ),
1340                         $this->addQuotes( $constraint )
1341                 );
1342                 $res = $this->query( $sql );
1343                 if ( !$res ) {
1344                         return null;
1345                 }
1346                 $rows = $res->numRows();
1347
1348                 return $rows;
1349         }
1350
1351         /**
1352          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1353          * @param string $schema
1354          * @return bool
1355          */
1356         function schemaExists( $schema ) {
1357                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1358                         [ 'nspname' => $schema ], __METHOD__ );
1359
1360                 return (bool)$exists;
1361         }
1362
1363         /**
1364          * Returns true if a given role (i.e. user) exists, false otherwise.
1365          * @param string $roleName
1366          * @return bool
1367          */
1368         function roleExists( $roleName ) {
1369                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1370                         [ 'rolname' => $roleName ], __METHOD__ );
1371
1372                 return (bool)$exists;
1373         }
1374
1375         /**
1376          * @var string $table
1377          * @var string $field
1378          * @return PostgresField|null
1379          */
1380         function fieldInfo( $table, $field ) {
1381                 return PostgresField::fromText( $this, $table, $field );
1382         }
1383
1384         /**
1385          * pg_field_type() wrapper
1386          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1387          * @param int $index Field number, starting from 0
1388          * @return string
1389          */
1390         function fieldType( $res, $index ) {
1391                 if ( $res instanceof ResultWrapper ) {
1392                         $res = $res->result;
1393                 }
1394
1395                 return pg_field_type( $res, $index );
1396         }
1397
1398         /**
1399          * @param string $b
1400          * @return Blob
1401          */
1402         function encodeBlob( $b ) {
1403                 return new PostgresBlob( pg_escape_bytea( $b ) );
1404         }
1405
1406         function decodeBlob( $b ) {
1407                 if ( $b instanceof PostgresBlob ) {
1408                         $b = $b->fetch();
1409                 } elseif ( $b instanceof Blob ) {
1410                         return $b->fetch();
1411                 }
1412
1413                 return pg_unescape_bytea( $b );
1414         }
1415
1416         function strencode( $s ) {
1417                 // Should not be called by us
1418
1419                 return pg_escape_string( $this->mConn, $s );
1420         }
1421
1422         /**
1423          * @param null|bool|Blob $s
1424          * @return int|string
1425          */
1426         function addQuotes( $s ) {
1427                 if ( is_null( $s ) ) {
1428                         return 'NULL';
1429                 } elseif ( is_bool( $s ) ) {
1430                         return intval( $s );
1431                 } elseif ( $s instanceof Blob ) {
1432                         if ( $s instanceof PostgresBlob ) {
1433                                 $s = $s->fetch();
1434                         } else {
1435                                 $s = pg_escape_bytea( $this->mConn, $s->fetch() );
1436                         }
1437                         return "'$s'";
1438                 }
1439
1440                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1441         }
1442
1443         /**
1444          * Postgres specific version of replaceVars.
1445          * Calls the parent version in Database.php
1446          *
1447          * @param string $ins SQL string, read from a stream (usually tables.sql)
1448          * @return string SQL string
1449          */
1450         protected function replaceVars( $ins ) {
1451                 $ins = parent::replaceVars( $ins );
1452
1453                 if ( $this->numericVersion >= 8.3 ) {
1454                         // Thanks for not providing backwards-compatibility, 8.3
1455                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1456                 }
1457
1458                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1459                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1460                 }
1461
1462                 return $ins;
1463         }
1464
1465         /**
1466          * Various select options
1467          *
1468          * @param array $options An associative array of options to be turned into
1469          *   an SQL query, valid keys are listed in the function.
1470          * @return array
1471          */
1472         function makeSelectOptions( $options ) {
1473                 $preLimitTail = $postLimitTail = '';
1474                 $startOpts = $useIndex = $ignoreIndex = '';
1475
1476                 $noKeyOptions = [];
1477                 foreach ( $options as $key => $option ) {
1478                         if ( is_numeric( $key ) ) {
1479                                 $noKeyOptions[$option] = true;
1480                         }
1481                 }
1482
1483                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1484
1485                 $preLimitTail .= $this->makeOrderBy( $options );
1486
1487                 // if ( isset( $options['LIMIT'] ) ) {
1488                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1489                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1490                 //              : false );
1491                 // }
1492
1493                 if ( isset( $options['FOR UPDATE'] ) ) {
1494                         $postLimitTail .= ' FOR UPDATE OF ' .
1495                                 implode( ', ', array_map( [ &$this, 'tableName' ], $options['FOR UPDATE'] ) );
1496                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1497                         $postLimitTail .= ' FOR UPDATE';
1498                 }
1499
1500                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1501                         $startOpts .= 'DISTINCT';
1502                 }
1503
1504                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1505         }
1506
1507         function getDBname() {
1508                 return $this->mDBname;
1509         }
1510
1511         function getServer() {
1512                 return $this->mServer;
1513         }
1514
1515         function buildConcat( $stringList ) {
1516                 return implode( ' || ', $stringList );
1517         }
1518
1519         public function buildGroupConcatField(
1520                 $delimiter, $table, $field, $conds = '', $options = [], $join_conds = []
1521         ) {
1522                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1523
1524                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1525         }
1526
1527         /**
1528          * @param string $field Field or column to cast
1529          * @return string
1530          * @since 1.28
1531          */
1532         public function buildStringCast( $field ) {
1533                 return $field . '::text';
1534         }
1535
1536         public function getSearchEngine() {
1537                 return 'SearchPostgres';
1538         }
1539
1540         public function streamStatementEnd( &$sql, &$newLine ) {
1541                 # Allow dollar quoting for function declarations
1542                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1543                         if ( $this->delimiter ) {
1544                                 $this->delimiter = false;
1545                         } else {
1546                                 $this->delimiter = ';';
1547                         }
1548                 }
1549
1550                 return parent::streamStatementEnd( $sql, $newLine );
1551         }
1552
1553         /**
1554          * Check to see if a named lock is available. This is non-blocking.
1555          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1556          *
1557          * @param string $lockName Name of lock to poll
1558          * @param string $method Name of method calling us
1559          * @return bool
1560          * @since 1.20
1561          */
1562         public function lockIsFree( $lockName, $method ) {
1563                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1564                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1565                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1566                 $row = $this->fetchObject( $result );
1567
1568                 return ( $row->lockstatus === 't' );
1569         }
1570
1571         /**
1572          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1573          * @param string $lockName
1574          * @param string $method
1575          * @param int $timeout
1576          * @return bool
1577          */
1578         public function lock( $lockName, $method, $timeout = 5 ) {
1579                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1580                 $loop = new WaitConditionLoop(
1581                         function () use ( $lockName, $key, $timeout, $method ) {
1582                                 $res = $this->query( "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1583                                 $row = $this->fetchObject( $res );
1584                                 if ( $row->lockstatus === 't' ) {
1585                                         parent::lock( $lockName, $method, $timeout ); // record
1586                                         return true;
1587                                 }
1588
1589                                 return WaitConditionLoop::CONDITION_CONTINUE;
1590                         },
1591                         $timeout
1592                 );
1593
1594                 return ( $loop->invoke() === $loop::CONDITION_REACHED );
1595         }
1596
1597         /**
1598          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1599          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1600          * @param string $lockName
1601          * @param string $method
1602          * @return bool
1603          */
1604         public function unlock( $lockName, $method ) {
1605                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1606                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1607                 $row = $this->fetchObject( $result );
1608
1609                 if ( $row->lockstatus === 't' ) {
1610                         parent::unlock( $lockName, $method ); // record
1611                         return true;
1612                 }
1613
1614                 wfDebug( __METHOD__ . " failed to release lock\n" );
1615
1616                 return false;
1617         }
1618
1619         /**
1620          * @param string $lockName
1621          * @return string Integer
1622          */
1623         private function bigintFromLockName( $lockName ) {
1624                 return Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1625         }
1626 } // end DatabasePostgres class