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