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  * Used to debug transaction processing
 133  * Only used if $wgDebugDBTransactions is true
 134  *
 135  * @since 1.19
 136  * @ingroup Database
 137  */
 138 class PostgresTransactionState {
 139         private 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         /** @var array */
 160         private $mNewState;
 161
 162         /** @var array */
 163         private $mCurrentState;
 164
 165         public function __construct( $conn ) {
 166                 $this->mConn = $conn;
 167                 $this->update();
 168                 $this->mCurrentState = $this->mNewState;
 169         }
 170
 171         public function update() {
 172                 $this->mNewState = array(
 173                         pg_connection_status( $this->mConn ),
 174                         pg_transaction_status( $this->mConn )
 175                 );
 176         }
 177
 178         public function check() {
 179                 global $wgDebugDBTransactions;
 180                 $this->update();
 181                 if ( $wgDebugDBTransactions ) {
 182                         if ( $this->mCurrentState !== $this->mNewState ) {
 183                                 $old = reset( $this->mCurrentState );
 184                                 $new = reset( $this->mNewState );
 185                                 foreach ( self::$WATCHED as $watched ) {
 186                                         if ( $old !== $new ) {
 187                                                 $this->log_changed( $old, $new, $watched );
 188                                         }
 189                                         $old = next( $this->mCurrentState );
 190                                         $new = next( $this->mNewState );
 191                                 }
 192                         }
 193                 }
 194                 $this->mCurrentState = $this->mNewState;
 195         }
 196
 197         protected function describe_changed( $status, $desc_table ) {
 198                 if ( isset( $desc_table[$status] ) ) {
 199                         return $desc_table[$status];
 200                 } else {
 201                         return "STATUS " . $status;
 202                 }
 203         }
 204
 205         protected function log_changed( $old, $new, $watched ) {
 206                 wfDebug( sprintf( $watched["desc"],
 207                         $this->mConn,
 208                         $this->describe_changed( $old, $watched["states"] ),
 209                         $this->describe_changed( $new, $watched["states"] )
 210                 ) );
 211         }
 212 }
 213
 214 /**
 215  * Manage savepoints within a transaction
 216  * @ingroup Database
 217  * @since 1.19
 218  */
 219 class SavepointPostgres {
 220         /** @var DatabasePostgres Establish a savepoint within a transaction */
 221         protected $dbw;
 222         protected $id;
 223         protected $didbegin;
 224
 225         /**
 226          * @param DatabaseBase $dbw
 227          * @param int $id
 228          */
 229         public function __construct( $dbw, $id ) {
 230                 $this->dbw = $dbw;
 231                 $this->id = $id;
 232                 $this->didbegin = false;
 233                 /* If we are not in a transaction, we need to be for savepoint trickery */
 234                 if ( !$dbw->trxLevel() ) {
 235                         $dbw->begin( "FOR SAVEPOINT" );
 236                         $this->didbegin = true;
 237                 }
 238         }
 239
 240         public function __destruct() {
 241                 if ( $this->didbegin ) {
 242                         $this->dbw->rollback();
 243                         $this->didbegin = false;
 244                 }
 245         }
 246
 247         public function commit() {
 248                 if ( $this->didbegin ) {
 249                         $this->dbw->commit();
 250                         $this->didbegin = false;
 251                 }
 252         }
 253
 254         protected function query( $keyword, $msg_ok, $msg_failed ) {
 255                 global $wgDebugDBTransactions;
 256                 if ( $this->dbw->doQuery( $keyword . " " . $this->id ) !== false ) {
 257                         if ( $wgDebugDBTransactions ) {
 258                                 wfDebug( sprintf( $msg_ok, $this->id ) );
 259                         }
 260                 } else {
 261                         wfDebug( sprintf( $msg_failed, $this->id ) );
 262                 }
 263         }
 264
 265         public function savepoint() {
 266                 $this->query( "SAVEPOINT",
 267                         "Transaction state: savepoint \"%s\" established.\n",
 268                         "Transaction state: establishment of savepoint \"%s\" FAILED.\n"
 269                 );
 270         }
 271
 272         public function release() {
 273                 $this->query( "RELEASE",
 274                         "Transaction state: savepoint \"%s\" released.\n",
 275                         "Transaction state: release of savepoint \"%s\" FAILED.\n"
 276                 );
 277         }
 278
 279         public function rollback() {
 280                 $this->query( "ROLLBACK TO",
 281                         "Transaction state: savepoint \"%s\" rolled back.\n",
 282                         "Transaction state: rollback of savepoint \"%s\" FAILED.\n"
 283                 );
 284         }
 285
 286         public function __toString() {
 287                 return (string)$this->id;
 288         }
 289 }
 290
 291 /**
 292  * @ingroup Database
 293  */
 294 class DatabasePostgres extends DatabaseBase {
 295         /** @var resource */
 296         protected $mLastResult = null;
 297
 298         /** @var int The number of rows affected as an integer */
 299         protected $mAffectedRows = null;
 300
 301         /** @var int */
 302         private $mInsertId = null;
 303
 304         /** @var float|string */
 305         private $numericVersion = null;
 306
 307         /** @var string Connect string to open a PostgreSQL connection */
 308         private $connectString;
 309
 310         /** @var PostgresTransactionState */
 311         private $mTransactionState;
 312
 313         /** @var string */
 314         private $mCoreSchema;
 315
 316         function getType() {
 317                 return 'postgres';
 318         }
 319
 320         function cascadingDeletes() {
 321                 return true;
 322         }
 323
 324         function cleanupTriggers() {
 325                 return true;
 326         }
 327
 328         function strictIPs() {
 329                 return true;
 330         }
 331
 332         function realTimestamps() {
 333                 return true;
 334         }
 335
 336         function implicitGroupby() {
 337                 return false;
 338         }
 339
 340         function implicitOrderby() {
 341                 return false;
 342         }
 343
 344         function searchableIPs() {
 345                 return true;
 346         }
 347
 348         function functionalIndexes() {
 349                 return true;
 350         }
 351
 352         function hasConstraint( $name ) {
 353                 $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
 354                         "WHERE c.connamespace = n.oid AND conname = '" .
 355                         pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" .
 356                         pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 357                 $res = $this->doQuery( $sql );
 358
 359                 return $this->numRows( $res );
 360         }
 361
 362         /**
 363          * Usually aborts on failure
 364          * @param string $server
 365          * @param string $user
 366          * @param string $password
 367          * @param string $dbName
 368          * @throws DBConnectionError|Exception
 369          * @return DatabaseBase|null
 370          */
 371         function open( $server, $user, $password, $dbName ) {
 372                 # Test for Postgres support, to avoid suppressed fatal error
 373                 if ( !function_exists( 'pg_connect' ) ) {
 374                         throw new DBConnectionError(
 375                                 $this,
 376                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
 377                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
 378                                 "webserver and database)\n"
 379                         );
 380                 }
 381
 382                 global $wgDBport;
 383
 384                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 385                         return null;
 386                 }
 387
 388                 $this->mServer = $server;
 389                 $port = $wgDBport;
 390                 $this->mUser = $user;
 391                 $this->mPassword = $password;
 392                 $this->mDBname = $dbName;
 393
 394                 $connectVars = array(
 395                         'dbname' => $dbName,
 396                         'user' => $user,
 397                         'password' => $password
 398                 );
 399                 if ( $server != false && $server != '' ) {
 400                         $connectVars['host'] = $server;
 401                 }
 402                 if ( $port != false && $port != '' ) {
 403                         $connectVars['port'] = $port;
 404                 }
 405                 if ( $this->mFlags & DBO_SSL ) {
 406                         $connectVars['sslmode'] = 1;
 407                 }
 408
 409                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 410                 $this->close();
 411                 $this->installErrorHandler();
 412
 413                 try {
 414                         $this->mConn = pg_connect( $this->connectString );
 415                 } catch ( Exception $ex ) {
 416                         $this->restoreErrorHandler();
 417                         throw $ex;
 418                 }
 419
 420                 $phpError = $this->restoreErrorHandler();
 421
 422                 if ( !$this->mConn ) {
 423                         wfDebug( "DB connection error\n" );
 424                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " .
 425                                 substr( $password, 0, 3 ) . "...\n" );
 426                         wfDebug( $this->lastError() . "\n" );
 427                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 428                 }
 429
 430                 $this->mOpened = true;
 431                 $this->mTransactionState = new PostgresTransactionState( $this->mConn );
 432
 433                 global $wgCommandLineMode;
 434                 # If called from the command-line (e.g. importDump), only show errors
 435                 if ( $wgCommandLineMode ) {
 436                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 437                 }
 438
 439                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 440                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 441                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 442                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 443                 if ( $this->getServerVersion() >= 9.0 ) {
 444                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 445                 }
 446
 447                 global $wgDBmwschema;
 448                 $this->determineCoreSchema( $wgDBmwschema );
 449
 450                 return $this->mConn;
 451         }
 452
 453         /**
 454          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 455          * DB name doesn't match the open connection, open a new one
 456          * @param string $db
 457          * @return bool
 458          */
 459         function selectDB( $db ) {
 460                 if ( $this->mDBname !== $db ) {
 461                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 462                 } else {
 463                         return true;
 464                 }
 465         }
 466
 467         function makeConnectionString( $vars ) {
 468                 $s = '';
 469                 foreach ( $vars as $name => $value ) {
 470                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 471                 }
 472
 473                 return $s;
 474         }
 475
 476         /**
 477          * Closes a database connection, if it is open
 478          * Returns success, true if already closed
 479          * @return bool
 480          */
 481         protected function closeConnection() {
 482                 return pg_close( $this->mConn );
 483         }
 484
 485         public function doQuery( $sql ) {
 486                 if ( function_exists( 'mb_convert_encoding' ) ) {
 487                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 488                 }
 489                 $this->mTransactionState->check();
 490                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 491                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 492                 }
 493                 $this->mLastResult = pg_get_result( $this->mConn );
 494                 $this->mTransactionState->check();
 495                 $this->mAffectedRows = null;
 496                 if ( pg_result_error( $this->mLastResult ) ) {
 497                         return false;
 498                 }
 499
 500                 return $this->mLastResult;
 501         }
 502
 503         protected function dumpError() {
 504                 $diags = array(
 505                         PGSQL_DIAG_SEVERITY,
 506                         PGSQL_DIAG_SQLSTATE,
 507                         PGSQL_DIAG_MESSAGE_PRIMARY,
 508                         PGSQL_DIAG_MESSAGE_DETAIL,
 509                         PGSQL_DIAG_MESSAGE_HINT,
 510                         PGSQL_DIAG_STATEMENT_POSITION,
 511                         PGSQL_DIAG_INTERNAL_POSITION,
 512                         PGSQL_DIAG_INTERNAL_QUERY,
 513                         PGSQL_DIAG_CONTEXT,
 514                         PGSQL_DIAG_SOURCE_FILE,
 515                         PGSQL_DIAG_SOURCE_LINE,
 516                         PGSQL_DIAG_SOURCE_FUNCTION
 517                 );
 518                 foreach ( $diags as $d ) {
 519                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n",
 520                                 $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 521                 }
 522         }
 523
 524         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 525                 if ( $tempIgnore ) {
 526                         /* Check for constraint violation */
 527                         if ( $errno === '23505' ) {
 528                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 529
 530                                 return;
 531                         }
 532                 }
 533                 /* Transaction stays in the ERROR state until rolled back */
 534                 if ( $this->mTrxLevel ) {
 535                         $ignore = $this->ignoreErrors( true );
 536                         $this->rollback( __METHOD__ );
 537                         $this->ignoreErrors( $ignore );
 538                 }
 539                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 540         }
 541
 542         function queryIgnore( $sql, $fname = __METHOD__ ) {
 543                 return $this->query( $sql, $fname, true );
 544         }
 545
 546         /**
 547          * @param stdClass|ResultWrapper $res
 548          * @throws DBUnexpectedError
 549          */
 550         function freeResult( $res ) {
 551                 if ( $res instanceof ResultWrapper ) {
 552                         $res = $res->result;
 553                 }
 554                 MediaWiki\suppressWarnings();
 555                 $ok = pg_free_result( $res );
 556                 MediaWiki\restoreWarnings();
 557                 if ( !$ok ) {
 558                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 559                 }
 560         }
 561
 562         /**
 563          * @param ResultWrapper|stdClass $res
 564          * @return stdClass
 565          * @throws DBUnexpectedError
 566          */
 567         function fetchObject( $res ) {
 568                 if ( $res instanceof ResultWrapper ) {
 569                         $res = $res->result;
 570                 }
 571                 MediaWiki\suppressWarnings();
 572                 $row = pg_fetch_object( $res );
 573                 MediaWiki\restoreWarnings();
 574                 # @todo FIXME: HACK HACK HACK HACK debug
 575
 576                 # @todo hashar: not sure if the following test really trigger if the object
 577                 #          fetching failed.
 578                 if ( pg_last_error( $this->mConn ) ) {
 579                         throw new DBUnexpectedError(
 580                                 $this,
 581                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 582                         );
 583                 }
 584
 585                 return $row;
 586         }
 587
 588         function fetchRow( $res ) {
 589                 if ( $res instanceof ResultWrapper ) {
 590                         $res = $res->result;
 591                 }
 592                 MediaWiki\suppressWarnings();
 593                 $row = pg_fetch_array( $res );
 594                 MediaWiki\restoreWarnings();
 595                 if ( pg_last_error( $this->mConn ) ) {
 596                         throw new DBUnexpectedError(
 597                                 $this,
 598                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 599                         );
 600                 }
 601
 602                 return $row;
 603         }
 604
 605         function numRows( $res ) {
 606                 if ( $res instanceof ResultWrapper ) {
 607                         $res = $res->result;
 608                 }
 609                 MediaWiki\suppressWarnings();
 610                 $n = pg_num_rows( $res );
 611                 MediaWiki\restoreWarnings();
 612                 if ( pg_last_error( $this->mConn ) ) {
 613                         throw new DBUnexpectedError(
 614                                 $this,
 615                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 616                         );
 617                 }
 618
 619                 return $n;
 620         }
 621
 622         function numFields( $res ) {
 623                 if ( $res instanceof ResultWrapper ) {
 624                         $res = $res->result;
 625                 }
 626
 627                 return pg_num_fields( $res );
 628         }
 629
 630         function fieldName( $res, $n ) {
 631                 if ( $res instanceof ResultWrapper ) {
 632                         $res = $res->result;
 633                 }
 634
 635                 return pg_field_name( $res, $n );
 636         }
 637
 638         /**
 639          * Return the result of the last call to nextSequenceValue();
 640          * This must be called after nextSequenceValue().
 641          *
 642          * @return int|null
 643          */
 644         function insertId() {
 645                 return $this->mInsertId;
 646         }
 647
 648         /**
 649          * @param mixed $res
 650          * @param int $row
 651          * @return bool
 652          */
 653         function dataSeek( $res, $row ) {
 654                 if ( $res instanceof ResultWrapper ) {
 655                         $res = $res->result;
 656                 }
 657
 658                 return pg_result_seek( $res, $row );
 659         }
 660
 661         function lastError() {
 662                 if ( $this->mConn ) {
 663                         if ( $this->mLastResult ) {
 664                                 return pg_result_error( $this->mLastResult );
 665                         } else {
 666                                 return pg_last_error();
 667                         }
 668                 } else {
 669                         return 'No database connection';
 670                 }
 671         }
 672
 673         function lastErrno() {
 674                 if ( $this->mLastResult ) {
 675                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 676                 } else {
 677                         return false;
 678                 }
 679         }
 680
 681         function affectedRows() {
 682                 if ( !is_null( $this->mAffectedRows ) ) {
 683                         // Forced result for simulated queries
 684                         return $this->mAffectedRows;
 685                 }
 686                 if ( empty( $this->mLastResult ) ) {
 687                         return 0;
 688                 }
 689
 690                 return pg_affected_rows( $this->mLastResult );
 691         }
 692
 693         /**
 694          * Estimate rows in dataset
 695          * Returns estimated count, based on EXPLAIN output
 696          * This is not necessarily an accurate estimate, so use sparingly
 697          * Returns -1 if count cannot be found
 698          * Takes same arguments as Database::select()
 699          *
 700          * @param string $table
 701          * @param string $vars
 702          * @param string $conds
 703          * @param string $fname
 704          * @param array $options
 705          * @return int
 706          */
 707         function estimateRowCount( $table, $vars = '*', $conds = '',
 708                 $fname = __METHOD__, $options = array()
 709         ) {
 710                 $options['EXPLAIN'] = true;
 711                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 712                 $rows = -1;
 713                 if ( $res ) {
 714                         $row = $this->fetchRow( $res );
 715                         $count = array();
 716                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 717                                 $rows = (int)$count[1];
 718                         }
 719                 }
 720
 721                 return $rows;
 722         }
 723
 724         /**
 725          * Returns information about an index
 726          * If errors are explicitly ignored, returns NULL on failure
 727          *
 728          * @param string $table
 729          * @param string $index
 730          * @param string $fname
 731          * @return bool|null
 732          */
 733         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 734                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 735                 $res = $this->query( $sql, $fname );
 736                 if ( !$res ) {
 737                         return null;
 738                 }
 739                 foreach ( $res as $row ) {
 740                         if ( $row->indexname == $this->indexName( $index ) ) {
 741                                 return $row;
 742                         }
 743                 }
 744
 745                 return false;
 746         }
 747
 748         /**
 749          * Returns is of attributes used in index
 750          *
 751          * @since 1.19
 752          * @param string $index
 753          * @param bool|string $schema
 754          * @return array
 755          */
 756         function indexAttributes( $index, $schema = false ) {
 757                 if ( $schema === false ) {
 758                         $schema = $this->getCoreSchema();
 759                 }
 760                 /*
 761                  * A subquery would be not needed if we didn't care about the order
 762                  * of attributes, but we do
 763                  */
 764                 $sql = <<<__INDEXATTR__
 765
 766                         SELECT opcname,
 767                                 attname,
 768                                 i.indoption[s.g] as option,
 769                                 pg_am.amname
 770                         FROM
 771                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 772                                         FROM
 773                                                 pg_index isub
 774                                         JOIN pg_class cis
 775                                                 ON cis.oid=isub.indexrelid
 776                                         JOIN pg_namespace ns
 777                                                 ON cis.relnamespace = ns.oid
 778                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 779                                 pg_attribute,
 780                                 pg_opclass opcls,
 781                                 pg_am,
 782                                 pg_class ci
 783                                 JOIN pg_index i
 784                                         ON ci.oid=i.indexrelid
 785                                 JOIN pg_class ct
 786                                         ON ct.oid = i.indrelid
 787                                 JOIN pg_namespace n
 788                                         ON ci.relnamespace = n.oid
 789                                 WHERE
 790                                         ci.relname='$index' AND n.nspname='$schema'
 791                                         AND     attrelid = ct.oid
 792                                         AND     i.indkey[s.g] = attnum
 793                                         AND     i.indclass[s.g] = opcls.oid
 794                                         AND     pg_am.oid = opcls.opcmethod
 795 __INDEXATTR__;
 796                 $res = $this->query( $sql, __METHOD__ );
 797                 $a = array();
 798                 if ( $res ) {
 799                         foreach ( $res as $row ) {
 800                                 $a[] = array(
 801                                         $row->attname,
 802                                         $row->opcname,
 803                                         $row->amname,
 804                                         $row->option );
 805                         }
 806                 } else {
 807                         return null;
 808                 }
 809
 810                 return $a;
 811         }
 812
 813         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 814                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 815                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 816                         $this->strencode( $this->indexName( $index ) ) .
 817                         ")'";
 818                 $res = $this->query( $sql, $fname );
 819                 if ( !$res ) {
 820                         return null;
 821                 }
 822
 823                 return $res->numRows() > 0;
 824         }
 825
 826         /**
 827          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 828          * to the parent function to get the actual SQL text.
 829          *
 830          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 831          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 832          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 833          *
 834          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 835          * @see DatabaseBase::selectSQLText
 836          */
 837         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 838                 $options = array(), $join_conds = array()
 839         ) {
 840                 if ( is_array( $options ) ) {
 841                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 842                         if ( $forUpdateKey !== false && $join_conds ) {
 843                                 unset( $options[$forUpdateKey] );
 844
 845                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 846                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 847                                                 $options['FOR UPDATE'][] = $table_cond;
 848                                         }
 849                                 }
 850                         }
 851
 852                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 853                                 unset( $options['ORDER BY'] );
 854                         }
 855                 }
 856
 857                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 858         }
 859
 860         /**
 861          * INSERT wrapper, inserts an array into a table
 862          *
 863          * $args may be a single associative array, or an array of these with numeric keys,
 864          * for multi-row insert (Postgres version 8.2 and above only).
 865          *
 866          * @param string $table Name of the table to insert to.
 867          * @param array $args Items to insert into the table.
 868          * @param string $fname Name of the function, for profiling
 869          * @param array|string $options String or array. Valid options: IGNORE
 870          * @return bool Success of insert operation. IGNORE always returns true.
 871          */
 872         function insert( $table, $args, $fname = __METHOD__, $options = array() ) {
 873                 if ( !count( $args ) ) {
 874                         return true;
 875                 }
 876
 877                 $table = $this->tableName( $table );
 878                 if ( !isset( $this->numericVersion ) ) {
 879                         $this->getServerVersion();
 880                 }
 881
 882                 if ( !is_array( $options ) ) {
 883                         $options = array( $options );
 884                 }
 885
 886                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 887                         $multi = true;
 888                         $keys = array_keys( $args[0] );
 889                 } else {
 890                         $multi = false;
 891                         $keys = array_keys( $args );
 892                 }
 893
 894                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 895                 $savepoint = null;
 896                 if ( in_array( 'IGNORE', $options ) ) {
 897                         $savepoint = new SavepointPostgres( $this, 'mw' );
 898                         $olde = error_reporting( 0 );
 899                         // For future use, we may want to track the number of actual inserts
 900                         // Right now, insert (all writes) simply return true/false
 901                         $numrowsinserted = 0;
 902                 }
 903
 904                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 905
 906                 if ( $multi ) {
 907                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 908                                 $first = true;
 909                                 foreach ( $args as $row ) {
 910                                         if ( $first ) {
 911                                                 $first = false;
 912                                         } else {
 913                                                 $sql .= ',';
 914                                         }
 915                                         $sql .= '(' . $this->makeList( $row ) . ')';
 916                                 }
 917                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 918                         } else {
 919                                 $res = true;
 920                                 $origsql = $sql;
 921                                 foreach ( $args as $row ) {
 922                                         $tempsql = $origsql;
 923                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 924
 925                                         if ( $savepoint ) {
 926                                                 $savepoint->savepoint();
 927                                         }
 928
 929                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 930
 931                                         if ( $savepoint ) {
 932                                                 $bar = pg_last_error();
 933                                                 if ( $bar != false ) {
 934                                                         $savepoint->rollback();
 935                                                 } else {
 936                                                         $savepoint->release();
 937                                                         $numrowsinserted++;
 938                                                 }
 939                                         }
 940
 941                                         // If any of them fail, we fail overall for this function call
 942                                         // Note that this will be ignored if IGNORE is set
 943                                         if ( !$tempres ) {
 944                                                 $res = false;
 945                                         }
 946                                 }
 947                         }
 948                 } else {
 949                         // Not multi, just a lone insert
 950                         if ( $savepoint ) {
 951                                 $savepoint->savepoint();
 952                         }
 953
 954                         $sql .= '(' . $this->makeList( $args ) . ')';
 955                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 956                         if ( $savepoint ) {
 957                                 $bar = pg_last_error();
 958                                 if ( $bar != false ) {
 959                                         $savepoint->rollback();
 960                                 } else {
 961                                         $savepoint->release();
 962                                         $numrowsinserted++;
 963                                 }
 964                         }
 965                 }
 966                 if ( $savepoint ) {
 967                         error_reporting( $olde );
 968                         $savepoint->commit();
 969
 970                         // Set the affected row count for the whole operation
 971                         $this->mAffectedRows = $numrowsinserted;
 972
 973                         // IGNORE always returns true
 974                         return true;
 975                 }
 976
 977                 return $res;
 978         }
 979
 980         /**
 981          * INSERT SELECT wrapper
 982          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 983          * Source items may be literals rather then field names, but strings should
 984          * be quoted with Database::addQuotes()
 985          * $conds may be "*" to copy the whole table
 986          * srcTable may be an array of tables.
 987          * @todo FIXME: Implement this a little better (seperate select/insert)?
 988          *
 989          * @param string $destTable
 990          * @param array|string $srcTable
 991          * @param array $varMap
 992          * @param array $conds
 993          * @param string $fname
 994          * @param array $insertOptions
 995          * @param array $selectOptions
 996          * @return bool
 997          */
 998         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 999                 $insertOptions = array(), $selectOptions = array() ) {
1000                 $destTable = $this->tableName( $destTable );
1001
1002                 if ( !is_array( $insertOptions ) ) {
1003                         $insertOptions = array( $insertOptions );
1004                 }
1005
1006                 /*
1007                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
1008                  * Ignore LOW PRIORITY option, since it is MySQL-specific
1009                  */
1010                 $savepoint = null;
1011                 if ( in_array( 'IGNORE', $insertOptions ) ) {
1012                         $savepoint = new SavepointPostgres( $this, 'mw' );
1013                         $olde = error_reporting( 0 );
1014                         $numrowsinserted = 0;
1015                         $savepoint->savepoint();
1016                 }
1017
1018                 if ( !is_array( $selectOptions ) ) {
1019                         $selectOptions = array( $selectOptions );
1020                 }
1021                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1022                 if ( is_array( $srcTable ) ) {
1023                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1024                 } else {
1025                         $srcTable = $this->tableName( $srcTable );
1026                 }
1027
1028                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1029                         " SELECT $startOpts " . implode( ',', $varMap ) .
1030                         " FROM $srcTable $useIndex";
1031
1032                 if ( $conds != '*' ) {
1033                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1034                 }
1035
1036                 $sql .= " $tailOpts";
1037
1038                 $res = (bool)$this->query( $sql, $fname, $savepoint );
1039                 if ( $savepoint ) {
1040                         $bar = pg_last_error();
1041                         if ( $bar != false ) {
1042                                 $savepoint->rollback();
1043                         } else {
1044                                 $savepoint->release();
1045                                 $numrowsinserted++;
1046                         }
1047                         error_reporting( $olde );
1048                         $savepoint->commit();
1049
1050                         // Set the affected row count for the whole operation
1051                         $this->mAffectedRows = $numrowsinserted;
1052
1053                         // IGNORE always returns true
1054                         return true;
1055                 }
1056
1057                 return $res;
1058         }
1059
1060         function tableName( $name, $format = 'quoted' ) {
1061                 # Replace reserved words with better ones
1062                 switch ( $name ) {
1063                         case 'user':
1064                                 return $this->realTableName( 'mwuser', $format );
1065                         case 'text':
1066                                 return $this->realTableName( 'pagecontent', $format );
1067                         default:
1068                                 return $this->realTableName( $name, $format );
1069                 }
1070         }
1071
1072         /* Don't cheat on installer */
1073         function realTableName( $name, $format = 'quoted' ) {
1074                 return parent::tableName( $name, $format );
1075         }
1076
1077         /**
1078          * Return the next in a sequence, save the value for retrieval via insertId()
1079          *
1080          * @param string $seqName
1081          * @return int|null
1082          */
1083         function nextSequenceValue( $seqName ) {
1084                 $safeseq = str_replace( "'", "''", $seqName );
1085                 $res = $this->query( "SELECT nextval('$safeseq')" );
1086                 $row = $this->fetchRow( $res );
1087                 $this->mInsertId = $row[0];
1088
1089                 return $this->mInsertId;
1090         }
1091
1092         /**
1093          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
1094          *
1095          * @param string $seqName
1096          * @return int
1097          */
1098         function currentSequenceValue( $seqName ) {
1099                 $safeseq = str_replace( "'", "''", $seqName );
1100                 $res = $this->query( "SELECT currval('$safeseq')" );
1101                 $row = $this->fetchRow( $res );
1102                 $currval = $row[0];
1103
1104                 return $currval;
1105         }
1106
1107         # Returns the size of a text field, or -1 for "unlimited"
1108         function textFieldSize( $table, $field ) {
1109                 $table = $this->tableName( $table );
1110                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1111                         FROM pg_class c, pg_attribute a, pg_type t
1112                         WHERE relname='$table' AND a.attrelid=c.oid AND
1113                                 a.atttypid=t.oid and a.attname='$field'";
1114                 $res = $this->query( $sql );
1115                 $row = $this->fetchObject( $res );
1116                 if ( $row->ftype == 'varchar' ) {
1117                         $size = $row->size - 4;
1118                 } else {
1119                         $size = $row->size;
1120                 }
1121
1122                 return $size;
1123         }
1124
1125         function limitResult( $sql, $limit, $offset = false ) {
1126                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1127         }
1128
1129         function wasDeadlock() {
1130                 return $this->lastErrno() == '40P01';
1131         }
1132
1133         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1134                 $newName = $this->addIdentifierQuotes( $newName );
1135                 $oldName = $this->addIdentifierQuotes( $oldName );
1136
1137                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1138                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1139         }
1140
1141         function listTables( $prefix = null, $fname = __METHOD__ ) {
1142                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1143                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1144                 $endArray = array();
1145
1146                 foreach ( $result as $table ) {
1147                         $vars = get_object_vars( $table );
1148                         $table = array_pop( $vars );
1149                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1150                                 $endArray[] = $table;
1151                         }
1152                 }
1153
1154                 return $endArray;
1155         }
1156
1157         function timestamp( $ts = 0 ) {
1158                 return wfTimestamp( TS_POSTGRES, $ts );
1159         }
1160
1161         /**
1162          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1163          * to http://www.php.net/manual/en/ref.pgsql.php
1164          *
1165          * Parsing a postgres array can be a tricky problem, he's my
1166          * take on this, it handles multi-dimensional arrays plus
1167          * escaping using a nasty regexp to determine the limits of each
1168          * data-item.
1169          *
1170          * This should really be handled by PHP PostgreSQL module
1171          *
1172          * @since 1.19
1173          * @param string $text Postgreql array returned in a text form like {a,b}
1174          * @param string $output
1175          * @param int $limit
1176          * @param int $offset
1177          * @return string
1178          */
1179         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1180                 if ( false === $limit ) {
1181                         $limit = strlen( $text ) - 1;
1182                         $output = array();
1183                 }
1184                 if ( '{}' == $text ) {
1185                         return $output;
1186                 }
1187                 do {
1188                         if ( '{' != $text[$offset] ) {
1189                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1190                                         $text, $match, 0, $offset );
1191                                 $offset += strlen( $match[0] );
1192                                 $output[] = ( '"' != $match[1][0]
1193                                         ? $match[1]
1194                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1195                                 if ( '},' == $match[3] ) {
1196                                         return $output;
1197                                 }
1198                         } else {
1199                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1200                         }
1201                 } while ( $limit > $offset );
1202
1203                 return $output;
1204         }
1205
1206         /**
1207          * Return aggregated value function call
1208          * @param array $valuedata
1209          * @param string $valuename
1210          * @return array
1211          */
1212         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1213                 return $valuedata;
1214         }
1215
1216         /**
1217          * @return string Wikitext of a link to the server software's web site
1218          */
1219         public function getSoftwareLink() {
1220                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1221         }
1222
1223         /**
1224          * Return current schema (executes SELECT current_schema())
1225          * Needs transaction
1226          *
1227          * @since 1.19
1228          * @return string Default schema for the current session
1229          */
1230         function getCurrentSchema() {
1231                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1232                 $row = $this->fetchRow( $res );
1233
1234                 return $row[0];
1235         }
1236
1237         /**
1238          * Return list of schemas which are accessible without schema name
1239          * This is list does not contain magic keywords like "$user"
1240          * Needs transaction
1241          *
1242          * @see getSearchPath()
1243          * @see setSearchPath()
1244          * @since 1.19
1245          * @return array List of actual schemas for the current sesson
1246          */
1247         function getSchemas() {
1248                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1249                 $row = $this->fetchRow( $res );
1250                 $schemas = array();
1251
1252                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1253
1254                 return $this->pg_array_parse( $row[0], $schemas );
1255         }
1256
1257         /**
1258          * Return search patch for schemas
1259          * This is different from getSchemas() since it contain magic keywords
1260          * (like "$user").
1261          * Needs transaction
1262          *
1263          * @since 1.19
1264          * @return array How to search for table names schemas for the current user
1265          */
1266         function getSearchPath() {
1267                 $res = $this->query( "SHOW search_path", __METHOD__ );
1268                 $row = $this->fetchRow( $res );
1269
1270                 /* PostgreSQL returns SHOW values as strings */
1271
1272                 return explode( ",", $row[0] );
1273         }
1274
1275         /**
1276          * Update search_path, values should already be sanitized
1277          * Values may contain magic keywords like "$user"
1278          * @since 1.19
1279          *
1280          * @param array $search_path List of schemas to be searched by default
1281          */
1282         function setSearchPath( $search_path ) {
1283                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1284         }
1285
1286         /**
1287          * Determine default schema for MediaWiki core
1288          * Adjust this session schema search path if desired schema exists
1289          * and is not alread there.
1290          *
1291          * We need to have name of the core schema stored to be able
1292          * to query database metadata.
1293          *
1294          * This will be also called by the installer after the schema is created
1295          *
1296          * @since 1.19
1297          *
1298          * @param string $desiredSchema
1299          */
1300         function determineCoreSchema( $desiredSchema ) {
1301                 $this->begin( __METHOD__ );
1302                 if ( $this->schemaExists( $desiredSchema ) ) {
1303                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1304                                 $this->mCoreSchema = $desiredSchema;
1305                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1306                         } else {
1307                                 /**
1308                                  * Prepend our schema (e.g. 'mediawiki') in front
1309                                  * of the search path
1310                                  * Fixes bug 15816
1311                                  */
1312                                 $search_path = $this->getSearchPath();
1313                                 array_unshift( $search_path,
1314                                         $this->addIdentifierQuotes( $desiredSchema ) );
1315                                 $this->setSearchPath( $search_path );
1316                                 $this->mCoreSchema = $desiredSchema;
1317                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1318                         }
1319                 } else {
1320                         $this->mCoreSchema = $this->getCurrentSchema();
1321                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1322                                 $this->mCoreSchema . "\"\n" );
1323                 }
1324                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1325                 $this->commit( __METHOD__ );
1326         }
1327
1328         /**
1329          * Return schema name fore core MediaWiki tables
1330          *
1331          * @since 1.19
1332          * @return string Core schema name
1333          */
1334         function getCoreSchema() {
1335                 return $this->mCoreSchema;
1336         }
1337
1338         /**
1339          * @return string Version information from the database
1340          */
1341         function getServerVersion() {
1342                 if ( !isset( $this->numericVersion ) ) {
1343                         $versionInfo = pg_version( $this->mConn );
1344                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1345                                 // Old client, abort install
1346                                 $this->numericVersion = '7.3 or earlier';
1347                         } elseif ( isset( $versionInfo['server'] ) ) {
1348                                 // Normal client
1349                                 $this->numericVersion = $versionInfo['server'];
1350                         } else {
1351                                 // Bug 16937: broken pgsql extension from PHP<5.3
1352                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1353                         }
1354                 }
1355
1356                 return $this->numericVersion;
1357         }
1358
1359         /**
1360          * Query whether a given relation exists (in the given schema, or the
1361          * default mw one if not given)
1362          * @param string $table
1363          * @param array|string $types
1364          * @param bool|string $schema
1365          * @return bool
1366          */
1367         function relationExists( $table, $types, $schema = false ) {
1368                 if ( !is_array( $types ) ) {
1369                         $types = array( $types );
1370                 }
1371                 if ( !$schema ) {
1372                         $schema = $this->getCoreSchema();
1373                 }
1374                 $table = $this->realTableName( $table, 'raw' );
1375                 $etable = $this->addQuotes( $table );
1376                 $eschema = $this->addQuotes( $schema );
1377                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1378                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1379                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1380                 $res = $this->query( $sql );
1381                 $count = $res ? $res->numRows() : 0;
1382
1383                 return (bool)$count;
1384         }
1385
1386         /**
1387          * For backward compatibility, this function checks both tables and
1388          * views.
1389          * @param string $table
1390          * @param string $fname
1391          * @param bool|string $schema
1392          * @return bool
1393          */
1394         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1395                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1396         }
1397
1398         function sequenceExists( $sequence, $schema = false ) {
1399                 return $this->relationExists( $sequence, 'S', $schema );
1400         }
1401
1402         function triggerExists( $table, $trigger ) {
1403                 $q = <<<SQL
1404         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1405                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1406                           AND tgrelid=pg_class.oid
1407                           AND nspname=%s AND relname=%s AND tgname=%s
1408 SQL;
1409                 $res = $this->query(
1410                         sprintf(
1411                                 $q,
1412                                 $this->addQuotes( $this->getCoreSchema() ),
1413                                 $this->addQuotes( $table ),
1414                                 $this->addQuotes( $trigger )
1415                         )
1416                 );
1417                 if ( !$res ) {
1418                         return null;
1419                 }
1420                 $rows = $res->numRows();
1421
1422                 return $rows;
1423         }
1424
1425         function ruleExists( $table, $rule ) {
1426                 $exists = $this->selectField( 'pg_rules', 'rulename',
1427                         array(
1428                                 'rulename' => $rule,
1429                                 'tablename' => $table,
1430                                 'schemaname' => $this->getCoreSchema()
1431                         )
1432                 );
1433
1434                 return $exists === $rule;
1435         }
1436
1437         function constraintExists( $table, $constraint ) {
1438                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1439                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1440                         $this->addQuotes( $this->getCoreSchema() ),
1441                         $this->addQuotes( $table ),
1442                         $this->addQuotes( $constraint )
1443                 );
1444                 $res = $this->query( $sql );
1445                 if ( !$res ) {
1446                         return null;
1447                 }
1448                 $rows = $res->numRows();
1449
1450                 return $rows;
1451         }
1452
1453         /**
1454          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1455          * @param string $schema
1456          * @return bool
1457          */
1458         function schemaExists( $schema ) {
1459                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1460                         array( 'nspname' => $schema ), __METHOD__ );
1461
1462                 return (bool)$exists;
1463         }
1464
1465         /**
1466          * Returns true if a given role (i.e. user) exists, false otherwise.
1467          * @param string $roleName
1468          * @return bool
1469          */
1470         function roleExists( $roleName ) {
1471                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1472                         array( 'rolname' => $roleName ), __METHOD__ );
1473
1474                 return (bool)$exists;
1475         }
1476
1477         function fieldInfo( $table, $field ) {
1478                 return PostgresField::fromText( $this, $table, $field );
1479         }
1480
1481         /**
1482          * pg_field_type() wrapper
1483          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1484          * @param int $index Field number, starting from 0
1485          * @return string
1486          */
1487         function fieldType( $res, $index ) {
1488                 if ( $res instanceof ResultWrapper ) {
1489                         $res = $res->result;
1490                 }
1491
1492                 return pg_field_type( $res, $index );
1493         }
1494
1495         /**
1496          * @param string $b
1497          * @return Blob
1498          */
1499         function encodeBlob( $b ) {
1500                 return new PostgresBlob( pg_escape_bytea( $b ) );
1501         }
1502
1503         function decodeBlob( $b ) {
1504                 if ( $b instanceof PostgresBlob ) {
1505                         $b = $b->fetch();
1506                 } elseif ( $b instanceof Blob ) {
1507                         return $b->fetch();
1508                 }
1509
1510                 return pg_unescape_bytea( $b );
1511         }
1512
1513         function strencode( $s ) {
1514                 // Should not be called by us
1515
1516                 return pg_escape_string( $this->mConn, $s );
1517         }
1518
1519         /**
1520          * @param null|bool|Blob $s
1521          * @return int|string
1522          */
1523         function addQuotes( $s ) {
1524                 if ( is_null( $s ) ) {
1525                         return 'NULL';
1526                 } elseif ( is_bool( $s ) ) {
1527                         return intval( $s );
1528                 } elseif ( $s instanceof Blob ) {
1529                         if ( $s instanceof PostgresBlob ) {
1530                                 $s = $s->fetch();
1531                         } else {
1532                                 $s = pg_escape_bytea( $this->mConn, $s->fetch() );
1533                         }
1534                         return "'$s'";
1535                 }
1536
1537                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1538         }
1539
1540         /**
1541          * Postgres specific version of replaceVars.
1542          * Calls the parent version in Database.php
1543          *
1544          * @param string $ins SQL string, read from a stream (usually tables.sql)
1545          * @return string SQL string
1546          */
1547         protected function replaceVars( $ins ) {
1548                 $ins = parent::replaceVars( $ins );
1549
1550                 if ( $this->numericVersion >= 8.3 ) {
1551                         // Thanks for not providing backwards-compatibility, 8.3
1552                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1553                 }
1554
1555                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1556                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1557                 }
1558
1559                 return $ins;
1560         }
1561
1562         /**
1563          * Various select options
1564          *
1565          * @param array $options An associative array of options to be turned into
1566          *   an SQL query, valid keys are listed in the function.
1567          * @return array
1568          */
1569         function makeSelectOptions( $options ) {
1570                 $preLimitTail = $postLimitTail = '';
1571                 $startOpts = $useIndex = '';
1572
1573                 $noKeyOptions = array();
1574                 foreach ( $options as $key => $option ) {
1575                         if ( is_numeric( $key ) ) {
1576                                 $noKeyOptions[$option] = true;
1577                         }
1578                 }
1579
1580                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1581
1582                 $preLimitTail .= $this->makeOrderBy( $options );
1583
1584                 //if ( isset( $options['LIMIT'] ) ) {
1585                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1586                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1587                 //              : false );
1588                 //}
1589
1590                 if ( isset( $options['FOR UPDATE'] ) ) {
1591                         $postLimitTail .= ' FOR UPDATE OF ' .
1592                                 implode( ', ', array_map( array( &$this, 'tableName' ), $options['FOR UPDATE'] ) );
1593                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1594                         $postLimitTail .= ' FOR UPDATE';
1595                 }
1596
1597                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1598                         $startOpts .= 'DISTINCT';
1599                 }
1600
1601                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1602         }
1603
1604         function getDBname() {
1605                 return $this->mDBname;
1606         }
1607
1608         function getServer() {
1609                 return $this->mServer;
1610         }
1611
1612         function buildConcat( $stringList ) {
1613                 return implode( ' || ', $stringList );
1614         }
1615
1616         public function buildGroupConcatField(
1617                 $delimiter, $table, $field, $conds = '', $options = array(), $join_conds = array()
1618         ) {
1619                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1620
1621                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
1622         }
1623
1624         public function getSearchEngine() {
1625                 return 'SearchPostgres';
1626         }
1627
1628         public function streamStatementEnd( &$sql, &$newLine ) {
1629                 # Allow dollar quoting for function declarations
1630                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1631                         if ( $this->delimiter ) {
1632                                 $this->delimiter = false;
1633                         } else {
1634                                 $this->delimiter = ';';
1635                         }
1636                 }
1637
1638                 return parent::streamStatementEnd( $sql, $newLine );
1639         }
1640
1641         /**
1642          * Check to see if a named lock is available. This is non-blocking.
1643          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1644          *
1645          * @param string $lockName Name of lock to poll
1646          * @param string $method Name of method calling us
1647          * @return bool
1648          * @since 1.20
1649          */
1650         public function lockIsFree( $lockName, $method ) {
1651                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1652                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1653                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1654                 $row = $this->fetchObject( $result );
1655
1656                 return ( $row->lockstatus === 't' );
1657         }
1658
1659         /**
1660          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1661          * @param string $lockName
1662          * @param string $method
1663          * @param int $timeout
1664          * @return bool
1665          */
1666         public function lock( $lockName, $method, $timeout = 5 ) {
1667                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1668                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1669                         $result = $this->query(
1670                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1671                         $row = $this->fetchObject( $result );
1672                         if ( $row->lockstatus === 't' ) {
1673                                 return true;
1674                         } else {
1675                                 sleep( 1 );
1676                         }
1677                 }
1678                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1679
1680                 return false;
1681         }
1682
1683         /**
1684          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1685          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1686          * @param string $lockName
1687          * @param string $method
1688          * @return bool
1689          */
1690         public function unlock( $lockName, $method ) {
1691                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1692                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1693                 $row = $this->fetchObject( $result );
1694
1695                 return ( $row->lockstatus === 't' );
1696         }
1697
1698         /**
1699          * @param string $lockName
1700          * @return string Integer
1701          */
1702         private function bigintFromLockName( $lockName ) {
1703                 return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1704         }
1705 } // end DatabasePostgres class
1706
1707 class PostgresBlob extends Blob {
1708 }