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 DatabaseBase $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 DatabaseBase $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" );
 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 Database {
 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 realTimestamps() {
 243                 return true;
 244         }
 245
 246         function implicitGroupby() {
 247                 return false;
 248         }
 249
 250         function implicitOrderby() {
 251                 return false;
 252         }
 253
 254         function searchableIPs() {
 255                 return true;
 256         }
 257
 258         function functionalIndexes() {
 259                 return true;
 260         }
 261
 262         function hasConstraint( $name ) {
 263                 $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
 264                         "WHERE c.connamespace = n.oid AND conname = '" .
 265                         pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" .
 266                         pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 267                 $res = $this->doQuery( $sql );
 268
 269                 return $this->numRows( $res );
 270         }
 271
 272         /**
 273          * Usually aborts on failure
 274          * @param string $server
 275          * @param string $user
 276          * @param string $password
 277          * @param string $dbName
 278          * @throws DBConnectionError|Exception
 279          * @return DatabaseBase|null
 280          */
 281         function open( $server, $user, $password, $dbName ) {
 282                 # Test for Postgres support, to avoid suppressed fatal error
 283                 if ( !function_exists( 'pg_connect' ) ) {
 284                         throw new DBConnectionError(
 285                                 $this,
 286                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
 287                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
 288                                 "webserver and database)\n"
 289                         );
 290                 }
 291
 292                 global $wgDBport;
 293
 294                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 295                         return null;
 296                 }
 297
 298                 $this->mServer = $server;
 299                 $port = $wgDBport;
 300                 $this->mUser = $user;
 301                 $this->mPassword = $password;
 302                 $this->mDBname = $dbName;
 303
 304                 $connectVars = array(
 305                         'dbname' => $dbName,
 306                         'user' => $user,
 307                         'password' => $password
 308                 );
 309                 if ( $server != false && $server != '' ) {
 310                         $connectVars['host'] = $server;
 311                 }
 312                 if ( $port != false && $port != '' ) {
 313                         $connectVars['port'] = $port;
 314                 }
 315                 if ( $this->mFlags & DBO_SSL ) {
 316                         $connectVars['sslmode'] = 1;
 317                 }
 318
 319                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 320                 $this->close();
 321                 $this->installErrorHandler();
 322
 323                 try {
 324                         $this->mConn = pg_connect( $this->connectString );
 325                 } catch ( Exception $ex ) {
 326                         $this->restoreErrorHandler();
 327                         throw $ex;
 328                 }
 329
 330                 $phpError = $this->restoreErrorHandler();
 331
 332                 if ( !$this->mConn ) {
 333                         wfDebug( "DB connection error\n" );
 334                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " .
 335                                 substr( $password, 0, 3 ) . "...\n" );
 336                         wfDebug( $this->lastError() . "\n" );
 337                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 338                 }
 339
 340                 $this->mOpened = true;
 341
 342                 global $wgCommandLineMode;
 343                 # If called from the command-line (e.g. importDump), only show errors
 344                 if ( $wgCommandLineMode ) {
 345                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 346                 }
 347
 348                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 349                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 350                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 351                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 352                 if ( $this->getServerVersion() >= 9.0 ) {
 353                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 354                 }
 355
 356                 global $wgDBmwschema;
 357                 $this->determineCoreSchema( $wgDBmwschema );
 358
 359                 return $this->mConn;
 360         }
 361
 362         /**
 363          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 364          * DB name doesn't match the open connection, open a new one
 365          * @param string $db
 366          * @return bool
 367          */
 368         function selectDB( $db ) {
 369                 if ( $this->mDBname !== $db ) {
 370                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 371                 } else {
 372                         return true;
 373                 }
 374         }
 375
 376         function makeConnectionString( $vars ) {
 377                 $s = '';
 378                 foreach ( $vars as $name => $value ) {
 379                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 380                 }
 381
 382                 return $s;
 383         }
 384
 385         /**
 386          * Closes a database connection, if it is open
 387          * Returns success, true if already closed
 388          * @return bool
 389          */
 390         protected function closeConnection() {
 391                 return pg_close( $this->mConn );
 392         }
 393
 394         public function doQuery( $sql ) {
 395                 if ( function_exists( 'mb_convert_encoding' ) ) {
 396                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 397                 }
 398                 // Clear previously left over PQresult
 399                 while ( $res = pg_get_result( $this->mConn ) ) {
 400                         pg_free_result( $res );
 401                 }
 402                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 403                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 404                 }
 405                 $this->mLastResult = pg_get_result( $this->mConn );
 406                 $this->mAffectedRows = null;
 407                 if ( pg_result_error( $this->mLastResult ) ) {
 408                         return false;
 409                 }
 410
 411                 return $this->mLastResult;
 412         }
 413
 414         protected function dumpError() {
 415                 $diags = array(
 416                         PGSQL_DIAG_SEVERITY,
 417                         PGSQL_DIAG_SQLSTATE,
 418                         PGSQL_DIAG_MESSAGE_PRIMARY,
 419                         PGSQL_DIAG_MESSAGE_DETAIL,
 420                         PGSQL_DIAG_MESSAGE_HINT,
 421                         PGSQL_DIAG_STATEMENT_POSITION,
 422                         PGSQL_DIAG_INTERNAL_POSITION,
 423                         PGSQL_DIAG_INTERNAL_QUERY,
 424                         PGSQL_DIAG_CONTEXT,
 425                         PGSQL_DIAG_SOURCE_FILE,
 426                         PGSQL_DIAG_SOURCE_LINE,
 427                         PGSQL_DIAG_SOURCE_FUNCTION
 428                 );
 429                 foreach ( $diags as $d ) {
 430                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n",
 431                                 $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 432                 }
 433         }
 434
 435         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 436                 if ( $tempIgnore ) {
 437                         /* Check for constraint violation */
 438                         if ( $errno === '23505' ) {
 439                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 440
 441                                 return;
 442                         }
 443                 }
 444                 /* Transaction stays in the ERROR state until rolled back */
 445                 if ( $this->mTrxLevel ) {
 446                         $ignore = $this->ignoreErrors( true );
 447                         $this->rollback( __METHOD__ );
 448                         $this->ignoreErrors( $ignore );
 449                 }
 450                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 451         }
 452
 453         function queryIgnore( $sql, $fname = __METHOD__ ) {
 454                 return $this->query( $sql, $fname, true );
 455         }
 456
 457         /**
 458          * @param stdClass|ResultWrapper $res
 459          * @throws DBUnexpectedError
 460          */
 461         function freeResult( $res ) {
 462                 if ( $res instanceof ResultWrapper ) {
 463                         $res = $res->result;
 464                 }
 465                 MediaWiki\suppressWarnings();
 466                 $ok = pg_free_result( $res );
 467                 MediaWiki\restoreWarnings();
 468                 if ( !$ok ) {
 469                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 470                 }
 471         }
 472
 473         /**
 474          * @param ResultWrapper|stdClass $res
 475          * @return stdClass
 476          * @throws DBUnexpectedError
 477          */
 478         function fetchObject( $res ) {
 479                 if ( $res instanceof ResultWrapper ) {
 480                         $res = $res->result;
 481                 }
 482                 MediaWiki\suppressWarnings();
 483                 $row = pg_fetch_object( $res );
 484                 MediaWiki\restoreWarnings();
 485                 # @todo FIXME: HACK HACK HACK HACK debug
 486
 487                 # @todo hashar: not sure if the following test really trigger if the object
 488                 #          fetching failed.
 489                 if ( pg_last_error( $this->mConn ) ) {
 490                         throw new DBUnexpectedError(
 491                                 $this,
 492                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 493                         );
 494                 }
 495
 496                 return $row;
 497         }
 498
 499         function fetchRow( $res ) {
 500                 if ( $res instanceof ResultWrapper ) {
 501                         $res = $res->result;
 502                 }
 503                 MediaWiki\suppressWarnings();
 504                 $row = pg_fetch_array( $res );
 505                 MediaWiki\restoreWarnings();
 506                 if ( pg_last_error( $this->mConn ) ) {
 507                         throw new DBUnexpectedError(
 508                                 $this,
 509                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 510                         );
 511                 }
 512
 513                 return $row;
 514         }
 515
 516         function numRows( $res ) {
 517                 if ( $res instanceof ResultWrapper ) {
 518                         $res = $res->result;
 519                 }
 520                 MediaWiki\suppressWarnings();
 521                 $n = pg_num_rows( $res );
 522                 MediaWiki\restoreWarnings();
 523                 if ( pg_last_error( $this->mConn ) ) {
 524                         throw new DBUnexpectedError(
 525                                 $this,
 526                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 527                         );
 528                 }
 529
 530                 return $n;
 531         }
 532
 533         function numFields( $res ) {
 534                 if ( $res instanceof ResultWrapper ) {
 535                         $res = $res->result;
 536                 }
 537
 538                 return pg_num_fields( $res );
 539         }
 540
 541         function fieldName( $res, $n ) {
 542                 if ( $res instanceof ResultWrapper ) {
 543                         $res = $res->result;
 544                 }
 545
 546                 return pg_field_name( $res, $n );
 547         }
 548
 549         /**
 550          * Return the result of the last call to nextSequenceValue();
 551          * This must be called after nextSequenceValue().
 552          *
 553          * @return int|null
 554          */
 555         function insertId() {
 556                 return $this->mInsertId;
 557         }
 558
 559         /**
 560          * @param mixed $res
 561          * @param int $row
 562          * @return bool
 563          */
 564         function dataSeek( $res, $row ) {
 565                 if ( $res instanceof ResultWrapper ) {
 566                         $res = $res->result;
 567                 }
 568
 569                 return pg_result_seek( $res, $row );
 570         }
 571
 572         function lastError() {
 573                 if ( $this->mConn ) {
 574                         if ( $this->mLastResult ) {
 575                                 return pg_result_error( $this->mLastResult );
 576                         } else {
 577                                 return pg_last_error();
 578                         }
 579                 } else {
 580                         return 'No database connection';
 581                 }
 582         }
 583
 584         function lastErrno() {
 585                 if ( $this->mLastResult ) {
 586                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 587                 } else {
 588                         return false;
 589                 }
 590         }
 591
 592         function affectedRows() {
 593                 if ( !is_null( $this->mAffectedRows ) ) {
 594                         // Forced result for simulated queries
 595                         return $this->mAffectedRows;
 596                 }
 597                 if ( empty( $this->mLastResult ) ) {
 598                         return 0;
 599                 }
 600
 601                 return pg_affected_rows( $this->mLastResult );
 602         }
 603
 604         /**
 605          * Estimate rows in dataset
 606          * Returns estimated count, based on EXPLAIN output
 607          * This is not necessarily an accurate estimate, so use sparingly
 608          * Returns -1 if count cannot be found
 609          * Takes same arguments as Database::select()
 610          *
 611          * @param string $table
 612          * @param string $vars
 613          * @param string $conds
 614          * @param string $fname
 615          * @param array $options
 616          * @return int
 617          */
 618         function estimateRowCount( $table, $vars = '*', $conds = '',
 619                 $fname = __METHOD__, $options = array()
 620         ) {
 621                 $options['EXPLAIN'] = true;
 622                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 623                 $rows = -1;
 624                 if ( $res ) {
 625                         $row = $this->fetchRow( $res );
 626                         $count = array();
 627                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 628                                 $rows = (int)$count[1];
 629                         }
 630                 }
 631
 632                 return $rows;
 633         }
 634
 635         /**
 636          * Returns information about an index
 637          * If errors are explicitly ignored, returns NULL on failure
 638          *
 639          * @param string $table
 640          * @param string $index
 641          * @param string $fname
 642          * @return bool|null
 643          */
 644         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 645                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 646                 $res = $this->query( $sql, $fname );
 647                 if ( !$res ) {
 648                         return null;
 649                 }
 650                 foreach ( $res as $row ) {
 651                         if ( $row->indexname == $this->indexName( $index ) ) {
 652                                 return $row;
 653                         }
 654                 }
 655
 656                 return false;
 657         }
 658
 659         /**
 660          * Returns is of attributes used in index
 661          *
 662          * @since 1.19
 663          * @param string $index
 664          * @param bool|string $schema
 665          * @return array
 666          */
 667         function indexAttributes( $index, $schema = false ) {
 668                 if ( $schema === false ) {
 669                         $schema = $this->getCoreSchema();
 670                 }
 671                 /*
 672                  * A subquery would be not needed if we didn't care about the order
 673                  * of attributes, but we do
 674                  */
 675                 $sql = <<<__INDEXATTR__
 676
 677                         SELECT opcname,
 678                                 attname,
 679                                 i.indoption[s.g] as option,
 680                                 pg_am.amname
 681                         FROM
 682                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 683                                         FROM
 684                                                 pg_index isub
 685                                         JOIN pg_class cis
 686                                                 ON cis.oid=isub.indexrelid
 687                                         JOIN pg_namespace ns
 688                                                 ON cis.relnamespace = ns.oid
 689                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 690                                 pg_attribute,
 691                                 pg_opclass opcls,
 692                                 pg_am,
 693                                 pg_class ci
 694                                 JOIN pg_index i
 695                                         ON ci.oid=i.indexrelid
 696                                 JOIN pg_class ct
 697                                         ON ct.oid = i.indrelid
 698                                 JOIN pg_namespace n
 699                                         ON ci.relnamespace = n.oid
 700                                 WHERE
 701                                         ci.relname='$index' AND n.nspname='$schema'
 702                                         AND     attrelid = ct.oid
 703                                         AND     i.indkey[s.g] = attnum
 704                                         AND     i.indclass[s.g] = opcls.oid
 705                                         AND     pg_am.oid = opcls.opcmethod
 706 __INDEXATTR__;
 707                 $res = $this->query( $sql, __METHOD__ );
 708                 $a = array();
 709                 if ( $res ) {
 710                         foreach ( $res as $row ) {
 711                                 $a[] = array(
 712                                         $row->attname,
 713                                         $row->opcname,
 714                                         $row->amname,
 715                                         $row->option );
 716                         }
 717                 } else {
 718                         return null;
 719                 }
 720
 721                 return $a;
 722         }
 723
 724         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 725                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 726                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 727                         $this->strencode( $this->indexName( $index ) ) .
 728                         ")'";
 729                 $res = $this->query( $sql, $fname );
 730                 if ( !$res ) {
 731                         return null;
 732                 }
 733
 734                 return $res->numRows() > 0;
 735         }
 736
 737         /**
 738          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 739          * to the parent function to get the actual SQL text.
 740          *
 741          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 742          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 743          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 744          *
 745          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 746          * @see DatabaseBase::selectSQLText
 747          */
 748         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 749                 $options = array(), $join_conds = array()
 750         ) {
 751                 if ( is_array( $options ) ) {
 752                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 753                         if ( $forUpdateKey !== false && $join_conds ) {
 754                                 unset( $options[$forUpdateKey] );
 755
 756                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 757                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 758                                                 $options['FOR UPDATE'][] = $table_cond;
 759                                         }
 760                                 }
 761                         }
 762
 763                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 764                                 unset( $options['ORDER BY'] );
 765                         }
 766                 }
 767
 768                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 769         }
 770
 771         /**
 772          * INSERT wrapper, inserts an array into a table
 773          *
 774          * $args may be a single associative array, or an array of these with numeric keys,
 775          * for multi-row insert (Postgres version 8.2 and above only).
 776          *
 777          * @param string $table Name of the table to insert to.
 778          * @param array $args Items to insert into the table.
 779          * @param string $fname Name of the function, for profiling
 780          * @param array|string $options String or array. Valid options: IGNORE
 781          * @return bool Success of insert operation. IGNORE always returns true.
 782          */
 783         function insert( $table, $args, $fname = __METHOD__, $options = array() ) {
 784                 if ( !count( $args ) ) {
 785                         return true;
 786                 }
 787
 788                 $table = $this->tableName( $table );
 789                 if ( !isset( $this->numericVersion ) ) {
 790                         $this->getServerVersion();
 791                 }
 792
 793                 if ( !is_array( $options ) ) {
 794                         $options = array( $options );
 795                 }
 796
 797                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 798                         $multi = true;
 799                         $keys = array_keys( $args[0] );
 800                 } else {
 801                         $multi = false;
 802                         $keys = array_keys( $args );
 803                 }
 804
 805                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 806                 $savepoint = null;
 807                 if ( in_array( 'IGNORE', $options ) ) {
 808                         $savepoint = new SavepointPostgres( $this, 'mw' );
 809                         $olde = error_reporting( 0 );
 810                         // For future use, we may want to track the number of actual inserts
 811                         // Right now, insert (all writes) simply return true/false
 812                         $numrowsinserted = 0;
 813                 }
 814
 815                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 816
 817                 if ( $multi ) {
 818                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 819                                 $first = true;
 820                                 foreach ( $args as $row ) {
 821                                         if ( $first ) {
 822                                                 $first = false;
 823                                         } else {
 824                                                 $sql .= ',';
 825                                         }
 826                                         $sql .= '(' . $this->makeList( $row ) . ')';
 827                                 }
 828                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 829                         } else {
 830                                 $res = true;
 831                                 $origsql = $sql;
 832                                 foreach ( $args as $row ) {
 833                                         $tempsql = $origsql;
 834                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 835
 836                                         if ( $savepoint ) {
 837                                                 $savepoint->savepoint();
 838                                         }
 839
 840                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 841
 842                                         if ( $savepoint ) {
 843                                                 $bar = pg_last_error();
 844                                                 if ( $bar != false ) {
 845                                                         $savepoint->rollback();
 846                                                 } else {
 847                                                         $savepoint->release();
 848                                                         $numrowsinserted++;
 849                                                 }
 850                                         }
 851
 852                                         // If any of them fail, we fail overall for this function call
 853                                         // Note that this will be ignored if IGNORE is set
 854                                         if ( !$tempres ) {
 855                                                 $res = false;
 856                                         }
 857                                 }
 858                         }
 859                 } else {
 860                         // Not multi, just a lone insert
 861                         if ( $savepoint ) {
 862                                 $savepoint->savepoint();
 863                         }
 864
 865                         $sql .= '(' . $this->makeList( $args ) . ')';
 866                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 867                         if ( $savepoint ) {
 868                                 $bar = pg_last_error();
 869                                 if ( $bar != false ) {
 870                                         $savepoint->rollback();
 871                                 } else {
 872                                         $savepoint->release();
 873                                         $numrowsinserted++;
 874                                 }
 875                         }
 876                 }
 877                 if ( $savepoint ) {
 878                         error_reporting( $olde );
 879                         $savepoint->commit();
 880
 881                         // Set the affected row count for the whole operation
 882                         $this->mAffectedRows = $numrowsinserted;
 883
 884                         // IGNORE always returns true
 885                         return true;
 886                 }
 887
 888                 return $res;
 889         }
 890
 891         /**
 892          * INSERT SELECT wrapper
 893          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 894          * Source items may be literals rather then field names, but strings should
 895          * be quoted with Database::addQuotes()
 896          * $conds may be "*" to copy the whole table
 897          * srcTable may be an array of tables.
 898          * @todo FIXME: Implement this a little better (seperate select/insert)?
 899          *
 900          * @param string $destTable
 901          * @param array|string $srcTable
 902          * @param array $varMap
 903          * @param array $conds
 904          * @param string $fname
 905          * @param array $insertOptions
 906          * @param array $selectOptions
 907          * @return bool
 908          */
 909         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 910                 $insertOptions = array(), $selectOptions = array() ) {
 911                 $destTable = $this->tableName( $destTable );
 912
 913                 if ( !is_array( $insertOptions ) ) {
 914                         $insertOptions = array( $insertOptions );
 915                 }
 916
 917                 /*
 918                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
 919                  * Ignore LOW PRIORITY option, since it is MySQL-specific
 920                  */
 921                 $savepoint = null;
 922                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 923                         $savepoint = new SavepointPostgres( $this, 'mw' );
 924                         $olde = error_reporting( 0 );
 925                         $numrowsinserted = 0;
 926                         $savepoint->savepoint();
 927                 }
 928
 929                 if ( !is_array( $selectOptions ) ) {
 930                         $selectOptions = array( $selectOptions );
 931                 }
 932                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
 933                 if ( is_array( $srcTable ) ) {
 934                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
 935                 } else {
 936                         $srcTable = $this->tableName( $srcTable );
 937                 }
 938
 939                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 940                         " SELECT $startOpts " . implode( ',', $varMap ) .
 941                         " FROM $srcTable $useIndex";
 942
 943                 if ( $conds != '*' ) {
 944                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 945                 }
 946
 947                 $sql .= " $tailOpts";
 948
 949                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 950                 if ( $savepoint ) {
 951                         $bar = pg_last_error();
 952                         if ( $bar != false ) {
 953                                 $savepoint->rollback();
 954                         } else {
 955                                 $savepoint->release();
 956                                 $numrowsinserted++;
 957                         }
 958                         error_reporting( $olde );
 959                         $savepoint->commit();
 960
 961                         // Set the affected row count for the whole operation
 962                         $this->mAffectedRows = $numrowsinserted;
 963
 964                         // IGNORE always returns true
 965                         return true;
 966                 }
 967
 968                 return $res;
 969         }
 970
 971         function tableName( $name, $format = 'quoted' ) {
 972                 # Replace reserved words with better ones
 973                 switch ( $name ) {
 974                         case 'user':
 975                                 return $this->realTableName( 'mwuser', $format );
 976                         case 'text':
 977                                 return $this->realTableName( 'pagecontent', $format );
 978                         default:
 979                                 return $this->realTableName( $name, $format );
 980                 }
 981         }
 982
 983         /* Don't cheat on installer */
 984         function realTableName( $name, $format = 'quoted' ) {
 985                 return parent::tableName( $name, $format );
 986         }
 987
 988         /**
 989          * Return the next in a sequence, save the value for retrieval via insertId()
 990          *
 991          * @param string $seqName
 992          * @return int|null
 993          */
 994         function nextSequenceValue( $seqName ) {
 995                 $safeseq = str_replace( "'", "''", $seqName );
 996                 $res = $this->query( "SELECT nextval('$safeseq')" );
 997                 $row = $this->fetchRow( $res );
 998                 $this->mInsertId = $row[0];
 999
1000                 return $this->mInsertId;
1001         }
1002
1003         /**
1004          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
1005          *
1006          * @param string $seqName
1007          * @return int
1008          */
1009         function currentSequenceValue( $seqName ) {
1010                 $safeseq = str_replace( "'", "''", $seqName );
1011                 $res = $this->query( "SELECT currval('$safeseq')" );
1012                 $row = $this->fetchRow( $res );
1013                 $currval = $row[0];
1014
1015                 return $currval;
1016         }
1017
1018         # Returns the size of a text field, or -1 for "unlimited"
1019         function textFieldSize( $table, $field ) {
1020                 $table = $this->tableName( $table );
1021                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1022                         FROM pg_class c, pg_attribute a, pg_type t
1023                         WHERE relname='$table' AND a.attrelid=c.oid AND
1024                                 a.atttypid=t.oid and a.attname='$field'";
1025                 $res = $this->query( $sql );
1026                 $row = $this->fetchObject( $res );
1027                 if ( $row->ftype == 'varchar' ) {
1028                         $size = $row->size - 4;
1029                 } else {
1030                         $size = $row->size;
1031                 }
1032
1033                 return $size;
1034         }
1035
1036         function limitResult( $sql, $limit, $offset = false ) {
1037                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1038         }
1039
1040         function wasDeadlock() {
1041                 return $this->lastErrno() == '40P01';
1042         }
1043
1044         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1045                 $newName = $this->addIdentifierQuotes( $newName );
1046                 $oldName = $this->addIdentifierQuotes( $oldName );
1047
1048                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1049                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1050         }
1051
1052         function listTables( $prefix = null, $fname = __METHOD__ ) {
1053                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1054                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1055                 $endArray = array();
1056
1057                 foreach ( $result as $table ) {
1058                         $vars = get_object_vars( $table );
1059                         $table = array_pop( $vars );
1060                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1061                                 $endArray[] = $table;
1062                         }
1063                 }
1064
1065                 return $endArray;
1066         }
1067
1068         function timestamp( $ts = 0 ) {
1069                 return wfTimestamp( TS_POSTGRES, $ts );
1070         }
1071
1072         /**
1073          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1074          * to http://www.php.net/manual/en/ref.pgsql.php
1075          *
1076          * Parsing a postgres array can be a tricky problem, he's my
1077          * take on this, it handles multi-dimensional arrays plus
1078          * escaping using a nasty regexp to determine the limits of each
1079          * data-item.
1080          *
1081          * This should really be handled by PHP PostgreSQL module
1082          *
1083          * @since 1.19
1084          * @param string $text Postgreql array returned in a text form like {a,b}
1085          * @param string $output
1086          * @param int $limit
1087          * @param int $offset
1088          * @return string
1089          */
1090         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1091                 if ( false === $limit ) {
1092                         $limit = strlen( $text ) - 1;
1093                         $output = array();
1094                 }
1095                 if ( '{}' == $text ) {
1096                         return $output;
1097                 }
1098                 do {
1099                         if ( '{' != $text[$offset] ) {
1100                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1101                                         $text, $match, 0, $offset );
1102                                 $offset += strlen( $match[0] );
1103                                 $output[] = ( '"' != $match[1][0]
1104                                         ? $match[1]
1105                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1106                                 if ( '},' == $match[3] ) {
1107                                         return $output;
1108                                 }
1109                         } else {
1110                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1111                         }
1112                 } while ( $limit > $offset );
1113
1114                 return $output;
1115         }
1116
1117         /**
1118          * Return aggregated value function call
1119          * @param array $valuedata
1120          * @param string $valuename
1121          * @return array
1122          */
1123         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1124                 return $valuedata;
1125         }
1126
1127         /**
1128          * @return string Wikitext of a link to the server software's web site
1129          */
1130         public function getSoftwareLink() {
1131                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1132         }
1133
1134         /**
1135          * Return current schema (executes SELECT current_schema())
1136          * Needs transaction
1137          *
1138          * @since 1.19
1139          * @return string Default schema for the current session
1140          */
1141         function getCurrentSchema() {
1142                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1143                 $row = $this->fetchRow( $res );
1144
1145                 return $row[0];
1146         }
1147
1148         /**
1149          * Return list of schemas which are accessible without schema name
1150          * This is list does not contain magic keywords like "$user"
1151          * Needs transaction
1152          *
1153          * @see getSearchPath()
1154          * @see setSearchPath()
1155          * @since 1.19
1156          * @return array List of actual schemas for the current sesson
1157          */
1158         function getSchemas() {
1159                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1160                 $row = $this->fetchRow( $res );
1161                 $schemas = array();
1162
1163                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1164
1165                 return $this->pg_array_parse( $row[0], $schemas );
1166         }
1167
1168         /**
1169          * Return search patch for schemas
1170          * This is different from getSchemas() since it contain magic keywords
1171          * (like "$user").
1172          * Needs transaction
1173          *
1174          * @since 1.19
1175          * @return array How to search for table names schemas for the current user
1176          */
1177         function getSearchPath() {
1178                 $res = $this->query( "SHOW search_path", __METHOD__ );
1179                 $row = $this->fetchRow( $res );
1180
1181                 /* PostgreSQL returns SHOW values as strings */
1182
1183                 return explode( ",", $row[0] );
1184         }
1185
1186         /**
1187          * Update search_path, values should already be sanitized
1188          * Values may contain magic keywords like "$user"
1189          * @since 1.19
1190          *
1191          * @param array $search_path List of schemas to be searched by default
1192          */
1193         function setSearchPath( $search_path ) {
1194                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1195         }
1196
1197         /**
1198          * Determine default schema for MediaWiki core
1199          * Adjust this session schema search path if desired schema exists
1200          * and is not alread there.
1201          *
1202          * We need to have name of the core schema stored to be able
1203          * to query database metadata.
1204          *
1205          * This will be also called by the installer after the schema is created
1206          *
1207          * @since 1.19
1208          *
1209          * @param string $desiredSchema
1210          */
1211         function determineCoreSchema( $desiredSchema ) {
1212                 $this->begin( __METHOD__ );
1213                 if ( $this->schemaExists( $desiredSchema ) ) {
1214                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1215                                 $this->mCoreSchema = $desiredSchema;
1216                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1217                         } else {
1218                                 /**
1219                                  * Prepend our schema (e.g. 'mediawiki') in front
1220                                  * of the search path
1221                                  * Fixes bug 15816
1222                                  */
1223                                 $search_path = $this->getSearchPath();
1224                                 array_unshift( $search_path,
1225                                         $this->addIdentifierQuotes( $desiredSchema ) );
1226                                 $this->setSearchPath( $search_path );
1227                                 $this->mCoreSchema = $desiredSchema;
1228                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1229                         }
1230                 } else {
1231                         $this->mCoreSchema = $this->getCurrentSchema();
1232                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1233                                 $this->mCoreSchema . "\"\n" );
1234                 }
1235                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1236                 $this->commit( __METHOD__ );
1237         }
1238
1239         /**
1240          * Return schema name fore core MediaWiki tables
1241          *
1242          * @since 1.19
1243          * @return string Core schema name
1244          */
1245         function getCoreSchema() {
1246                 return $this->mCoreSchema;
1247         }
1248
1249         /**
1250          * @return string Version information from the database
1251          */
1252         function getServerVersion() {
1253                 if ( !isset( $this->numericVersion ) ) {
1254                         $versionInfo = pg_version( $this->mConn );
1255                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1256                                 // Old client, abort install
1257                                 $this->numericVersion = '7.3 or earlier';
1258                         } elseif ( isset( $versionInfo['server'] ) ) {
1259                                 // Normal client
1260                                 $this->numericVersion = $versionInfo['server'];
1261                         } else {
1262                                 // Bug 16937: broken pgsql extension from PHP<5.3
1263                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1264                         }
1265                 }
1266
1267                 return $this->numericVersion;
1268         }
1269
1270         /**
1271          * Query whether a given relation exists (in the given schema, or the
1272          * default mw one if not given)
1273          * @param string $table
1274          * @param array|string $types
1275          * @param bool|string $schema
1276          * @return bool
1277          */
1278         function relationExists( $table, $types, $schema = false ) {
1279                 if ( !is_array( $types ) ) {
1280                         $types = array( $types );
1281                 }
1282                 if ( !$schema ) {
1283                         $schema = $this->getCoreSchema();
1284                 }
1285                 $table = $this->realTableName( $table, 'raw' );
1286                 $etable = $this->addQuotes( $table );
1287                 $eschema = $this->addQuotes( $schema );
1288                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1289                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1290                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1291                 $res = $this->query( $sql );
1292                 $count = $res ? $res->numRows() : 0;
1293
1294                 return (bool)$count;
1295         }
1296
1297         /**
1298          * For backward compatibility, this function checks both tables and
1299          * views.
1300          * @param string $table
1301          * @param string $fname
1302          * @param bool|string $schema
1303          * @return bool
1304          */
1305         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1306                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1307         }
1308
1309         function sequenceExists( $sequence, $schema = false ) {
1310                 return $this->relationExists( $sequence, 'S', $schema );
1311         }
1312
1313         function triggerExists( $table, $trigger ) {
1314                 $q = <<<SQL
1315         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1316                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1317                           AND tgrelid=pg_class.oid
1318                           AND nspname=%s AND relname=%s AND tgname=%s
1319 SQL;
1320                 $res = $this->query(
1321                         sprintf(
1322                                 $q,
1323                                 $this->addQuotes( $this->getCoreSchema() ),
1324                                 $this->addQuotes( $table ),
1325                                 $this->addQuotes( $trigger )
1326                         )
1327                 );
1328                 if ( !$res ) {
1329                         return null;
1330                 }
1331                 $rows = $res->numRows();
1332
1333                 return $rows;
1334         }
1335
1336         function ruleExists( $table, $rule ) {
1337                 $exists = $this->selectField( 'pg_rules', 'rulename',
1338                         array(
1339                                 'rulename' => $rule,
1340                                 'tablename' => $table,
1341                                 'schemaname' => $this->getCoreSchema()
1342                         )
1343                 );
1344
1345                 return $exists === $rule;
1346         }
1347
1348         function constraintExists( $table, $constraint ) {
1349                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1350                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1351                         $this->addQuotes( $this->getCoreSchema() ),
1352                         $this->addQuotes( $table ),
1353                         $this->addQuotes( $constraint )
1354                 );
1355                 $res = $this->query( $sql );
1356                 if ( !$res ) {
1357                         return null;
1358                 }
1359                 $rows = $res->numRows();
1360
1361                 return $rows;
1362         }
1363
1364         /**
1365          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1366          * @param string $schema
1367          * @return bool
1368          */
1369         function schemaExists( $schema ) {
1370                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1371                         array( 'nspname' => $schema ), __METHOD__ );
1372
1373                 return (bool)$exists;
1374         }
1375
1376         /**
1377          * Returns true if a given role (i.e. user) exists, false otherwise.
1378          * @param string $roleName
1379          * @return bool
1380          */
1381         function roleExists( $roleName ) {
1382                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1383                         array( 'rolname' => $roleName ), __METHOD__ );
1384
1385                 return (bool)$exists;
1386         }
1387
1388         function fieldInfo( $table, $field ) {
1389                 return PostgresField::fromText( $this, $table, $field );
1390         }
1391
1392         /**
1393          * pg_field_type() wrapper
1394          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1395          * @param int $index Field number, starting from 0
1396          * @return string
1397          */
1398         function fieldType( $res, $index ) {
1399                 if ( $res instanceof ResultWrapper ) {
1400                         $res = $res->result;
1401                 }
1402
1403                 return pg_field_type( $res, $index );
1404         }
1405
1406         /**
1407          * @param string $b
1408          * @return Blob
1409          */
1410         function encodeBlob( $b ) {
1411                 return new PostgresBlob( pg_escape_bytea( $b ) );
1412         }
1413
1414         function decodeBlob( $b ) {
1415                 if ( $b instanceof PostgresBlob ) {
1416                         $b = $b->fetch();
1417                 } elseif ( $b instanceof Blob ) {
1418                         return $b->fetch();
1419                 }
1420
1421                 return pg_unescape_bytea( $b );
1422         }
1423
1424         function strencode( $s ) {
1425                 // Should not be called by us
1426
1427                 return pg_escape_string( $this->mConn, $s );
1428         }
1429
1430         /**
1431          * @param null|bool|Blob $s
1432          * @return int|string
1433          */
1434         function addQuotes( $s ) {
1435                 if ( is_null( $s ) ) {
1436                         return 'NULL';
1437                 } elseif ( is_bool( $s ) ) {
1438                         return intval( $s );
1439                 } elseif ( $s instanceof Blob ) {
1440                         if ( $s instanceof PostgresBlob ) {
1441                                 $s = $s->fetch();
1442                         } else {
1443                                 $s = pg_escape_bytea( $this->mConn, $s->fetch() );
1444                         }
1445                         return "'$s'";
1446                 }
1447
1448                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1449         }
1450
1451         /**
1452          * Postgres specific version of replaceVars.
1453          * Calls the parent version in Database.php
1454          *
1455          * @param string $ins SQL string, read from a stream (usually tables.sql)
1456          * @return string SQL string
1457          */
1458         protected function replaceVars( $ins ) {
1459                 $ins = parent::replaceVars( $ins );
1460
1461                 if ( $this->numericVersion >= 8.3 ) {
1462                         // Thanks for not providing backwards-compatibility, 8.3
1463                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1464                 }
1465
1466                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1467                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1468                 }
1469
1470                 return $ins;
1471         }
1472
1473         /**
1474          * Various select options
1475          *
1476          * @param array $options An associative array of options to be turned into
1477          *   an SQL query, valid keys are listed in the function.
1478          * @return array
1479          */
1480         function makeSelectOptions( $options ) {
1481                 $preLimitTail = $postLimitTail = '';
1482                 $startOpts = $useIndex = '';
1483
1484                 $noKeyOptions = array();
1485                 foreach ( $options as $key => $option ) {
1486                         if ( is_numeric( $key ) ) {
1487                                 $noKeyOptions[$option] = true;
1488                         }
1489                 }
1490
1491                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1492
1493                 $preLimitTail .= $this->makeOrderBy( $options );
1494
1495                 // if ( isset( $options['LIMIT'] ) ) {
1496                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1497                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1498                 //              : false );
1499                 // }
1500
1501                 if ( isset( $options['FOR UPDATE'] ) ) {
1502                         $postLimitTail .= ' FOR UPDATE OF ' .
1503                                 implode( ', ', array_map( array( &$this, 'tableName' ), $options['FOR UPDATE'] ) );
1504                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1505                         $postLimitTail .= ' FOR UPDATE';
1506                 }
1507
1508                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1509                         $startOpts .= 'DISTINCT';
1510                 }
1511
1512                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1513         }
1514
1515         function getDBname() {
1516                 return $this->mDBname;
1517         }
1518
1519         function getServer() {
1520                 return $this->mServer;
1521         }
1522
1523         function buildConcat( $stringList ) {
1524                 return implode( ' || ', $stringList );
1525         }
1526
1527         public function buildGroupConcatField(
1528                 $delimiter, $table, $field, $conds = '', $options = array(), $join_conds = array()
1529         ) {
1530                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1531
1532                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
1533         }
1534
1535         public function getSearchEngine() {
1536                 return 'SearchPostgres';
1537         }
1538
1539         public function streamStatementEnd( &$sql, &$newLine ) {
1540                 # Allow dollar quoting for function declarations
1541                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1542                         if ( $this->delimiter ) {
1543                                 $this->delimiter = false;
1544                         } else {
1545                                 $this->delimiter = ';';
1546                         }
1547                 }
1548
1549                 return parent::streamStatementEnd( $sql, $newLine );
1550         }
1551
1552         /**
1553          * Check to see if a named lock is available. This is non-blocking.
1554          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1555          *
1556          * @param string $lockName Name of lock to poll
1557          * @param string $method Name of method calling us
1558          * @return bool
1559          * @since 1.20
1560          */
1561         public function lockIsFree( $lockName, $method ) {
1562                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1563                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1564                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1565                 $row = $this->fetchObject( $result );
1566
1567                 return ( $row->lockstatus === 't' );
1568         }
1569
1570         /**
1571          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1572          * @param string $lockName
1573          * @param string $method
1574          * @param int $timeout
1575          * @return bool
1576          */
1577         public function lock( $lockName, $method, $timeout = 5 ) {
1578                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1579                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1580                         $result = $this->query(
1581                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1582                         $row = $this->fetchObject( $result );
1583                         if ( $row->lockstatus === 't' ) {
1584                                 parent::lock( $lockName, $method, $timeout ); // record
1585                                 return true;
1586                         } else {
1587                                 sleep( 1 );
1588                         }
1589                 }
1590
1591                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1592
1593                 return false;
1594         }
1595
1596         /**
1597          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1598          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1599          * @param string $lockName
1600          * @param string $method
1601          * @return bool
1602          */
1603         public function unlock( $lockName, $method ) {
1604                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1605                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1606                 $row = $this->fetchObject( $result );
1607
1608                 if ( $row->lockstatus === 't' ) {
1609                         parent::unlock( $lockName, $method ); // record
1610                         return true;
1611                 }
1612
1613                 wfDebug( __METHOD__ . " failed to release lock\n" );
1614
1615                 return false;
1616         }
1617
1618         /**
1619          * @param string $lockName
1620          * @return string Integer
1621          */
1622         private function bigintFromLockName( $lockName ) {
1623                 return Wikimedia\base_convert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1624         }
1625 } // end DatabasePostgres class
1626
1627 class PostgresBlob extends Blob {
1628 }