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 DatabaseBase 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 rolledback */
 534                 if ( $this->mTrxLevel ) {
 535                         $this->rollback( __METHOD__ );
 536                 };
 537                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 538         }
 539
 540         function queryIgnore( $sql, $fname = __METHOD__ ) {
 541                 return $this->query( $sql, $fname, true );
 542         }
 543
 544         /**
 545          * @param stdClass|ResultWrapper $res
 546          * @throws DBUnexpectedError
 547          */
 548         function freeResult( $res ) {
 549                 if ( $res instanceof ResultWrapper ) {
 550                         $res = $res->result;
 551                 }
 552                 wfSuppressWarnings();
 553                 $ok = pg_free_result( $res );
 554                 wfRestoreWarnings();
 555                 if ( !$ok ) {
 556                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 557                 }
 558         }
 559
 560         /**
 561          * @param ResultWrapper|stdClass $res
 562          * @return stdClass
 563          * @throws DBUnexpectedError
 564          */
 565         function fetchObject( $res ) {
 566                 if ( $res instanceof ResultWrapper ) {
 567                         $res = $res->result;
 568                 }
 569                 wfSuppressWarnings();
 570                 $row = pg_fetch_object( $res );
 571                 wfRestoreWarnings();
 572                 # @todo FIXME: HACK HACK HACK HACK debug
 573
 574                 # @todo hashar: not sure if the following test really trigger if the object
 575                 #          fetching failed.
 576                 if ( pg_last_error( $this->mConn ) ) {
 577                         throw new DBUnexpectedError(
 578                                 $this,
 579                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 580                         );
 581                 }
 582
 583                 return $row;
 584         }
 585
 586         function fetchRow( $res ) {
 587                 if ( $res instanceof ResultWrapper ) {
 588                         $res = $res->result;
 589                 }
 590                 wfSuppressWarnings();
 591                 $row = pg_fetch_array( $res );
 592                 wfRestoreWarnings();
 593                 if ( pg_last_error( $this->mConn ) ) {
 594                         throw new DBUnexpectedError(
 595                                 $this,
 596                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 597                         );
 598                 }
 599
 600                 return $row;
 601         }
 602
 603         function numRows( $res ) {
 604                 if ( $res instanceof ResultWrapper ) {
 605                         $res = $res->result;
 606                 }
 607                 wfSuppressWarnings();
 608                 $n = pg_num_rows( $res );
 609                 wfRestoreWarnings();
 610                 if ( pg_last_error( $this->mConn ) ) {
 611                         throw new DBUnexpectedError(
 612                                 $this,
 613                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 614                         );
 615                 }
 616
 617                 return $n;
 618         }
 619
 620         function numFields( $res ) {
 621                 if ( $res instanceof ResultWrapper ) {
 622                         $res = $res->result;
 623                 }
 624
 625                 return pg_num_fields( $res );
 626         }
 627
 628         function fieldName( $res, $n ) {
 629                 if ( $res instanceof ResultWrapper ) {
 630                         $res = $res->result;
 631                 }
 632
 633                 return pg_field_name( $res, $n );
 634         }
 635
 636         /**
 637          * Return the result of the last call to nextSequenceValue();
 638          * This must be called after nextSequenceValue().
 639          *
 640          * @return int|null
 641          */
 642         function insertId() {
 643                 return $this->mInsertId;
 644         }
 645
 646         /**
 647          * @param mixed $res
 648          * @param int $row
 649          * @return bool
 650          */
 651         function dataSeek( $res, $row ) {
 652                 if ( $res instanceof ResultWrapper ) {
 653                         $res = $res->result;
 654                 }
 655
 656                 return pg_result_seek( $res, $row );
 657         }
 658
 659         function lastError() {
 660                 if ( $this->mConn ) {
 661                         if ( $this->mLastResult ) {
 662                                 return pg_result_error( $this->mLastResult );
 663                         } else {
 664                                 return pg_last_error();
 665                         }
 666                 } else {
 667                         return 'No database connection';
 668                 }
 669         }
 670
 671         function lastErrno() {
 672                 if ( $this->mLastResult ) {
 673                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 674                 } else {
 675                         return false;
 676                 }
 677         }
 678
 679         function affectedRows() {
 680                 if ( !is_null( $this->mAffectedRows ) ) {
 681                         // Forced result for simulated queries
 682                         return $this->mAffectedRows;
 683                 }
 684                 if ( empty( $this->mLastResult ) ) {
 685                         return 0;
 686                 }
 687
 688                 return pg_affected_rows( $this->mLastResult );
 689         }
 690
 691         /**
 692          * Estimate rows in dataset
 693          * Returns estimated count, based on EXPLAIN output
 694          * This is not necessarily an accurate estimate, so use sparingly
 695          * Returns -1 if count cannot be found
 696          * Takes same arguments as Database::select()
 697          *
 698          * @param string $table
 699          * @param string $vars
 700          * @param string $conds
 701          * @param string $fname
 702          * @param array $options
 703          * @return int
 704          */
 705         function estimateRowCount( $table, $vars = '*', $conds = '',
 706                 $fname = __METHOD__, $options = array()
 707         ) {
 708                 $options['EXPLAIN'] = true;
 709                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 710                 $rows = -1;
 711                 if ( $res ) {
 712                         $row = $this->fetchRow( $res );
 713                         $count = array();
 714                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 715                                 $rows = $count[1];
 716                         }
 717                 }
 718
 719                 return $rows;
 720         }
 721
 722         /**
 723          * Returns information about an index
 724          * If errors are explicitly ignored, returns NULL on failure
 725          *
 726          * @param string $table
 727          * @param string $index
 728          * @param string $fname
 729          * @return bool|null
 730          */
 731         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 732                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 733                 $res = $this->query( $sql, $fname );
 734                 if ( !$res ) {
 735                         return null;
 736                 }
 737                 foreach ( $res as $row ) {
 738                         if ( $row->indexname == $this->indexName( $index ) ) {
 739                                 return $row;
 740                         }
 741                 }
 742
 743                 return false;
 744         }
 745
 746         /**
 747          * Returns is of attributes used in index
 748          *
 749          * @since 1.19
 750          * @param string $index
 751          * @param bool|string $schema
 752          * @return array
 753          */
 754         function indexAttributes( $index, $schema = false ) {
 755                 if ( $schema === false ) {
 756                         $schema = $this->getCoreSchema();
 757                 }
 758                 /*
 759                  * A subquery would be not needed if we didn't care about the order
 760                  * of attributes, but we do
 761                  */
 762                 $sql = <<<__INDEXATTR__
 763
 764                         SELECT opcname,
 765                                 attname,
 766                                 i.indoption[s.g] as option,
 767                                 pg_am.amname
 768                         FROM
 769                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 770                                         FROM
 771                                                 pg_index isub
 772                                         JOIN pg_class cis
 773                                                 ON cis.oid=isub.indexrelid
 774                                         JOIN pg_namespace ns
 775                                                 ON cis.relnamespace = ns.oid
 776                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 777                                 pg_attribute,
 778                                 pg_opclass opcls,
 779                                 pg_am,
 780                                 pg_class ci
 781                                 JOIN pg_index i
 782                                         ON ci.oid=i.indexrelid
 783                                 JOIN pg_class ct
 784                                         ON ct.oid = i.indrelid
 785                                 JOIN pg_namespace n
 786                                         ON ci.relnamespace = n.oid
 787                                 WHERE
 788                                         ci.relname='$index' AND n.nspname='$schema'
 789                                         AND     attrelid = ct.oid
 790                                         AND     i.indkey[s.g] = attnum
 791                                         AND     i.indclass[s.g] = opcls.oid
 792                                         AND     pg_am.oid = opcls.opcmethod
 793 __INDEXATTR__;
 794                 $res = $this->query( $sql, __METHOD__ );
 795                 $a = array();
 796                 if ( $res ) {
 797                         foreach ( $res as $row ) {
 798                                 $a[] = array(
 799                                         $row->attname,
 800                                         $row->opcname,
 801                                         $row->amname,
 802                                         $row->option );
 803                         }
 804                 } else {
 805                         return null;
 806                 }
 807
 808                 return $a;
 809         }
 810
 811         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 812                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 813                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 814                         $this->strencode( $this->indexName( $index ) ) .
 815                         ")'";
 816                 $res = $this->query( $sql, $fname );
 817                 if ( !$res ) {
 818                         return null;
 819                 }
 820
 821                 return $res->numRows() > 0;
 822         }
 823
 824         /**
 825          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 826          * to the parent function to get the actual SQL text.
 827          *
 828          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 829          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 830          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 831          *
 832          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 833          * @see DatabaseBase::selectSQLText
 834          */
 835         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 836                 $options = array(), $join_conds = array()
 837         ) {
 838                 if ( is_array( $options ) ) {
 839                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 840                         if ( $forUpdateKey !== false && $join_conds ) {
 841                                 unset( $options[$forUpdateKey] );
 842
 843                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 844                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 845                                                 $options['FOR UPDATE'][] = $table_cond;
 846                                         }
 847                                 }
 848                         }
 849
 850                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 851                                 unset( $options['ORDER BY'] );
 852                         }
 853                 }
 854
 855                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 856         }
 857
 858         /**
 859          * INSERT wrapper, inserts an array into a table
 860          *
 861          * $args may be a single associative array, or an array of these with numeric keys,
 862          * for multi-row insert (Postgres version 8.2 and above only).
 863          *
 864          * @param string $table Name of the table to insert to.
 865          * @param array $args Items to insert into the table.
 866          * @param string $fname Name of the function, for profiling
 867          * @param array|string $options String or array. Valid options: IGNORE
 868          * @return bool Success of insert operation. IGNORE always returns true.
 869          */
 870         function insert( $table, $args, $fname = __METHOD__, $options = array() ) {
 871                 if ( !count( $args ) ) {
 872                         return true;
 873                 }
 874
 875                 $table = $this->tableName( $table );
 876                 if ( !isset( $this->numericVersion ) ) {
 877                         $this->getServerVersion();
 878                 }
 879
 880                 if ( !is_array( $options ) ) {
 881                         $options = array( $options );
 882                 }
 883
 884                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 885                         $multi = true;
 886                         $keys = array_keys( $args[0] );
 887                 } else {
 888                         $multi = false;
 889                         $keys = array_keys( $args );
 890                 }
 891
 892                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 893                 $savepoint = null;
 894                 if ( in_array( 'IGNORE', $options ) ) {
 895                         $savepoint = new SavepointPostgres( $this, 'mw' );
 896                         $olde = error_reporting( 0 );
 897                         // For future use, we may want to track the number of actual inserts
 898                         // Right now, insert (all writes) simply return true/false
 899                         $numrowsinserted = 0;
 900                 }
 901
 902                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 903
 904                 if ( $multi ) {
 905                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 906                                 $first = true;
 907                                 foreach ( $args as $row ) {
 908                                         if ( $first ) {
 909                                                 $first = false;
 910                                         } else {
 911                                                 $sql .= ',';
 912                                         }
 913                                         $sql .= '(' . $this->makeList( $row ) . ')';
 914                                 }
 915                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 916                         } else {
 917                                 $res = true;
 918                                 $origsql = $sql;
 919                                 foreach ( $args as $row ) {
 920                                         $tempsql = $origsql;
 921                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 922
 923                                         if ( $savepoint ) {
 924                                                 $savepoint->savepoint();
 925                                         }
 926
 927                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 928
 929                                         if ( $savepoint ) {
 930                                                 $bar = pg_last_error();
 931                                                 if ( $bar != false ) {
 932                                                         $savepoint->rollback();
 933                                                 } else {
 934                                                         $savepoint->release();
 935                                                         $numrowsinserted++;
 936                                                 }
 937                                         }
 938
 939                                         // If any of them fail, we fail overall for this function call
 940                                         // Note that this will be ignored if IGNORE is set
 941                                         if ( !$tempres ) {
 942                                                 $res = false;
 943                                         }
 944                                 }
 945                         }
 946                 } else {
 947                         // Not multi, just a lone insert
 948                         if ( $savepoint ) {
 949                                 $savepoint->savepoint();
 950                         }
 951
 952                         $sql .= '(' . $this->makeList( $args ) . ')';
 953                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 954                         if ( $savepoint ) {
 955                                 $bar = pg_last_error();
 956                                 if ( $bar != false ) {
 957                                         $savepoint->rollback();
 958                                 } else {
 959                                         $savepoint->release();
 960                                         $numrowsinserted++;
 961                                 }
 962                         }
 963                 }
 964                 if ( $savepoint ) {
 965                         error_reporting( $olde );
 966                         $savepoint->commit();
 967
 968                         // Set the affected row count for the whole operation
 969                         $this->mAffectedRows = $numrowsinserted;
 970
 971                         // IGNORE always returns true
 972                         return true;
 973                 }
 974
 975                 return $res;
 976         }
 977
 978         /**
 979          * INSERT SELECT wrapper
 980          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 981          * Source items may be literals rather then field names, but strings should
 982          * be quoted with Database::addQuotes()
 983          * $conds may be "*" to copy the whole table
 984          * srcTable may be an array of tables.
 985          * @todo FIXME: Implement this a little better (seperate select/insert)?
 986          *
 987          * @param string $destTable
 988          * @param array|string $srcTable
 989          * @param array $varMap
 990          * @param array $conds
 991          * @param string $fname
 992          * @param array $insertOptions
 993          * @param array $selectOptions
 994          * @return bool
 995          */
 996         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 997                 $insertOptions = array(), $selectOptions = array() ) {
 998                 $destTable = $this->tableName( $destTable );
 999
1000                 if ( !is_array( $insertOptions ) ) {
1001                         $insertOptions = array( $insertOptions );
1002                 }
1003
1004                 /*
1005                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
1006                  * Ignore LOW PRIORITY option, since it is MySQL-specific
1007                  */
1008                 $savepoint = null;
1009                 if ( in_array( 'IGNORE', $insertOptions ) ) {
1010                         $savepoint = new SavepointPostgres( $this, 'mw' );
1011                         $olde = error_reporting( 0 );
1012                         $numrowsinserted = 0;
1013                         $savepoint->savepoint();
1014                 }
1015
1016                 if ( !is_array( $selectOptions ) ) {
1017                         $selectOptions = array( $selectOptions );
1018                 }
1019                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1020                 if ( is_array( $srcTable ) ) {
1021                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1022                 } else {
1023                         $srcTable = $this->tableName( $srcTable );
1024                 }
1025
1026                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1027                         " SELECT $startOpts " . implode( ',', $varMap ) .
1028                         " FROM $srcTable $useIndex";
1029
1030                 if ( $conds != '*' ) {
1031                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1032                 }
1033
1034                 $sql .= " $tailOpts";
1035
1036                 $res = (bool)$this->query( $sql, $fname, $savepoint );
1037                 if ( $savepoint ) {
1038                         $bar = pg_last_error();
1039                         if ( $bar != false ) {
1040                                 $savepoint->rollback();
1041                         } else {
1042                                 $savepoint->release();
1043                                 $numrowsinserted++;
1044                         }
1045                         error_reporting( $olde );
1046                         $savepoint->commit();
1047
1048                         // Set the affected row count for the whole operation
1049                         $this->mAffectedRows = $numrowsinserted;
1050
1051                         // IGNORE always returns true
1052                         return true;
1053                 }
1054
1055                 return $res;
1056         }
1057
1058         function tableName( $name, $format = 'quoted' ) {
1059                 # Replace reserved words with better ones
1060                 switch ( $name ) {
1061                         case 'user':
1062                                 return $this->realTableName( 'mwuser', $format );
1063                         case 'text':
1064                                 return $this->realTableName( 'pagecontent', $format );
1065                         default:
1066                                 return $this->realTableName( $name, $format );
1067                 }
1068         }
1069
1070         /* Don't cheat on installer */
1071         function realTableName( $name, $format = 'quoted' ) {
1072                 return parent::tableName( $name, $format );
1073         }
1074
1075         /**
1076          * Return the next in a sequence, save the value for retrieval via insertId()
1077          *
1078          * @param string $seqName
1079          * @return int|null
1080          */
1081         function nextSequenceValue( $seqName ) {
1082                 $safeseq = str_replace( "'", "''", $seqName );
1083                 $res = $this->query( "SELECT nextval('$safeseq')" );
1084                 $row = $this->fetchRow( $res );
1085                 $this->mInsertId = $row[0];
1086
1087                 return $this->mInsertId;
1088         }
1089
1090         /**
1091          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
1092          *
1093          * @param string $seqName
1094          * @return int
1095          */
1096         function currentSequenceValue( $seqName ) {
1097                 $safeseq = str_replace( "'", "''", $seqName );
1098                 $res = $this->query( "SELECT currval('$safeseq')" );
1099                 $row = $this->fetchRow( $res );
1100                 $currval = $row[0];
1101
1102                 return $currval;
1103         }
1104
1105         # Returns the size of a text field, or -1 for "unlimited"
1106         function textFieldSize( $table, $field ) {
1107                 $table = $this->tableName( $table );
1108                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1109                         FROM pg_class c, pg_attribute a, pg_type t
1110                         WHERE relname='$table' AND a.attrelid=c.oid AND
1111                                 a.atttypid=t.oid and a.attname='$field'";
1112                 $res = $this->query( $sql );
1113                 $row = $this->fetchObject( $res );
1114                 if ( $row->ftype == 'varchar' ) {
1115                         $size = $row->size - 4;
1116                 } else {
1117                         $size = $row->size;
1118                 }
1119
1120                 return $size;
1121         }
1122
1123         function limitResult( $sql, $limit, $offset = false ) {
1124                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1125         }
1126
1127         function wasDeadlock() {
1128                 return $this->lastErrno() == '40P01';
1129         }
1130
1131         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1132                 $newName = $this->addIdentifierQuotes( $newName );
1133                 $oldName = $this->addIdentifierQuotes( $oldName );
1134
1135                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1136                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1137         }
1138
1139         function listTables( $prefix = null, $fname = __METHOD__ ) {
1140                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1141                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1142                 $endArray = array();
1143
1144                 foreach ( $result as $table ) {
1145                         $vars = get_object_vars( $table );
1146                         $table = array_pop( $vars );
1147                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1148                                 $endArray[] = $table;
1149                         }
1150                 }
1151
1152                 return $endArray;
1153         }
1154
1155         function timestamp( $ts = 0 ) {
1156                 return wfTimestamp( TS_POSTGRES, $ts );
1157         }
1158
1159         /**
1160          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1161          * to http://www.php.net/manual/en/ref.pgsql.php
1162          *
1163          * Parsing a postgres array can be a tricky problem, he's my
1164          * take on this, it handles multi-dimensional arrays plus
1165          * escaping using a nasty regexp to determine the limits of each
1166          * data-item.
1167          *
1168          * This should really be handled by PHP PostgreSQL module
1169          *
1170          * @since 1.19
1171          * @param string $text Postgreql array returned in a text form like {a,b}
1172          * @param string $output
1173          * @param int $limit
1174          * @param int $offset
1175          * @return string
1176          */
1177         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1178                 if ( false === $limit ) {
1179                         $limit = strlen( $text ) - 1;
1180                         $output = array();
1181                 }
1182                 if ( '{}' == $text ) {
1183                         return $output;
1184                 }
1185                 do {
1186                         if ( '{' != $text[$offset] ) {
1187                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1188                                         $text, $match, 0, $offset );
1189                                 $offset += strlen( $match[0] );
1190                                 $output[] = ( '"' != $match[1][0]
1191                                         ? $match[1]
1192                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1193                                 if ( '},' == $match[3] ) {
1194                                         return $output;
1195                                 }
1196                         } else {
1197                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1198                         }
1199                 } while ( $limit > $offset );
1200
1201                 return $output;
1202         }
1203
1204         /**
1205          * Return aggregated value function call
1206          * @param array $valuedata
1207          * @param string $valuename
1208          * @return array
1209          */
1210         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1211                 return $valuedata;
1212         }
1213
1214         /**
1215          * @return string Wikitext of a link to the server software's web site
1216          */
1217         public function getSoftwareLink() {
1218                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1219         }
1220
1221         /**
1222          * Return current schema (executes SELECT current_schema())
1223          * Needs transaction
1224          *
1225          * @since 1.19
1226          * @return string Default schema for the current session
1227          */
1228         function getCurrentSchema() {
1229                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1230                 $row = $this->fetchRow( $res );
1231
1232                 return $row[0];
1233         }
1234
1235         /**
1236          * Return list of schemas which are accessible without schema name
1237          * This is list does not contain magic keywords like "$user"
1238          * Needs transaction
1239          *
1240          * @see getSearchPath()
1241          * @see setSearchPath()
1242          * @since 1.19
1243          * @return array List of actual schemas for the current sesson
1244          */
1245         function getSchemas() {
1246                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1247                 $row = $this->fetchRow( $res );
1248                 $schemas = array();
1249
1250                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1251
1252                 return $this->pg_array_parse( $row[0], $schemas );
1253         }
1254
1255         /**
1256          * Return search patch for schemas
1257          * This is different from getSchemas() since it contain magic keywords
1258          * (like "$user").
1259          * Needs transaction
1260          *
1261          * @since 1.19
1262          * @return array How to search for table names schemas for the current user
1263          */
1264         function getSearchPath() {
1265                 $res = $this->query( "SHOW search_path", __METHOD__ );
1266                 $row = $this->fetchRow( $res );
1267
1268                 /* PostgreSQL returns SHOW values as strings */
1269
1270                 return explode( ",", $row[0] );
1271         }
1272
1273         /**
1274          * Update search_path, values should already be sanitized
1275          * Values may contain magic keywords like "$user"
1276          * @since 1.19
1277          *
1278          * @param array $search_path List of schemas to be searched by default
1279          */
1280         function setSearchPath( $search_path ) {
1281                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1282         }
1283
1284         /**
1285          * Determine default schema for MediaWiki core
1286          * Adjust this session schema search path if desired schema exists
1287          * and is not alread there.
1288          *
1289          * We need to have name of the core schema stored to be able
1290          * to query database metadata.
1291          *
1292          * This will be also called by the installer after the schema is created
1293          *
1294          * @since 1.19
1295          *
1296          * @param string $desiredSchema
1297          */
1298         function determineCoreSchema( $desiredSchema ) {
1299                 $this->begin( __METHOD__ );
1300                 if ( $this->schemaExists( $desiredSchema ) ) {
1301                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1302                                 $this->mCoreSchema = $desiredSchema;
1303                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1304                         } else {
1305                                 /**
1306                                  * Prepend our schema (e.g. 'mediawiki') in front
1307                                  * of the search path
1308                                  * Fixes bug 15816
1309                                  */
1310                                 $search_path = $this->getSearchPath();
1311                                 array_unshift( $search_path,
1312                                         $this->addIdentifierQuotes( $desiredSchema ) );
1313                                 $this->setSearchPath( $search_path );
1314                                 $this->mCoreSchema = $desiredSchema;
1315                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1316                         }
1317                 } else {
1318                         $this->mCoreSchema = $this->getCurrentSchema();
1319                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1320                                 $this->mCoreSchema . "\"\n" );
1321                 }
1322                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1323                 $this->commit( __METHOD__ );
1324         }
1325
1326         /**
1327          * Return schema name fore core MediaWiki tables
1328          *
1329          * @since 1.19
1330          * @return string Core schema name
1331          */
1332         function getCoreSchema() {
1333                 return $this->mCoreSchema;
1334         }
1335
1336         /**
1337          * @return string Version information from the database
1338          */
1339         function getServerVersion() {
1340                 if ( !isset( $this->numericVersion ) ) {
1341                         $versionInfo = pg_version( $this->mConn );
1342                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1343                                 // Old client, abort install
1344                                 $this->numericVersion = '7.3 or earlier';
1345                         } elseif ( isset( $versionInfo['server'] ) ) {
1346                                 // Normal client
1347                                 $this->numericVersion = $versionInfo['server'];
1348                         } else {
1349                                 // Bug 16937: broken pgsql extension from PHP<5.3
1350                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1351                         }
1352                 }
1353
1354                 return $this->numericVersion;
1355         }
1356
1357         /**
1358          * Query whether a given relation exists (in the given schema, or the
1359          * default mw one if not given)
1360          * @param string $table
1361          * @param array|string $types
1362          * @param bool|string $schema
1363          * @return bool
1364          */
1365         function relationExists( $table, $types, $schema = false ) {
1366                 if ( !is_array( $types ) ) {
1367                         $types = array( $types );
1368                 }
1369                 if ( !$schema ) {
1370                         $schema = $this->getCoreSchema();
1371                 }
1372                 $table = $this->realTableName( $table, 'raw' );
1373                 $etable = $this->addQuotes( $table );
1374                 $eschema = $this->addQuotes( $schema );
1375                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1376                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1377                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1378                 $res = $this->query( $sql );
1379                 $count = $res ? $res->numRows() : 0;
1380
1381                 return (bool)$count;
1382         }
1383
1384         /**
1385          * For backward compatibility, this function checks both tables and
1386          * views.
1387          * @param string $table
1388          * @param string $fname
1389          * @param bool|string $schema
1390          * @return bool
1391          */
1392         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1393                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1394         }
1395
1396         function sequenceExists( $sequence, $schema = false ) {
1397                 return $this->relationExists( $sequence, 'S', $schema );
1398         }
1399
1400         function triggerExists( $table, $trigger ) {
1401                 $q = <<<SQL
1402         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1403                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1404                           AND tgrelid=pg_class.oid
1405                           AND nspname=%s AND relname=%s AND tgname=%s
1406 SQL;
1407                 $res = $this->query(
1408                         sprintf(
1409                                 $q,
1410                                 $this->addQuotes( $this->getCoreSchema() ),
1411                                 $this->addQuotes( $table ),
1412                                 $this->addQuotes( $trigger )
1413                         )
1414                 );
1415                 if ( !$res ) {
1416                         return null;
1417                 }
1418                 $rows = $res->numRows();
1419
1420                 return $rows;
1421         }
1422
1423         function ruleExists( $table, $rule ) {
1424                 $exists = $this->selectField( 'pg_rules', 'rulename',
1425                         array(
1426                                 'rulename' => $rule,
1427                                 'tablename' => $table,
1428                                 'schemaname' => $this->getCoreSchema()
1429                         )
1430                 );
1431
1432                 return $exists === $rule;
1433         }
1434
1435         function constraintExists( $table, $constraint ) {
1436                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1437                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1438                         $this->addQuotes( $this->getCoreSchema() ),
1439                         $this->addQuotes( $table ),
1440                         $this->addQuotes( $constraint )
1441                 );
1442                 $res = $this->query( $sql );
1443                 if ( !$res ) {
1444                         return null;
1445                 }
1446                 $rows = $res->numRows();
1447
1448                 return $rows;
1449         }
1450
1451         /**
1452          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1453          * @param string $schema
1454          * @return bool
1455          */
1456         function schemaExists( $schema ) {
1457                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1458                         array( 'nspname' => $schema ), __METHOD__ );
1459
1460                 return (bool)$exists;
1461         }
1462
1463         /**
1464          * Returns true if a given role (i.e. user) exists, false otherwise.
1465          * @param string $roleName
1466          * @return bool
1467          */
1468         function roleExists( $roleName ) {
1469                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1470                         array( 'rolname' => $roleName ), __METHOD__ );
1471
1472                 return (bool)$exists;
1473         }
1474
1475         function fieldInfo( $table, $field ) {
1476                 return PostgresField::fromText( $this, $table, $field );
1477         }
1478
1479         /**
1480          * pg_field_type() wrapper
1481          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1482          * @param int $index Field number, starting from 0
1483          * @return string
1484          */
1485         function fieldType( $res, $index ) {
1486                 if ( $res instanceof ResultWrapper ) {
1487                         $res = $res->result;
1488                 }
1489
1490                 return pg_field_type( $res, $index );
1491         }
1492
1493         /**
1494          * @param string $b
1495          * @return Blob
1496          */
1497         function encodeBlob( $b ) {
1498                 return new Blob( pg_escape_bytea( $this->mConn, $b ) );
1499         }
1500
1501         function decodeBlob( $b ) {
1502                 if ( $b instanceof Blob ) {
1503                         $b = $b->fetch();
1504                 }
1505
1506                 return pg_unescape_bytea( $b );
1507         }
1508
1509         function strencode( $s ) { # Should not be called by us
1510                 return pg_escape_string( $this->mConn, $s );
1511         }
1512
1513         /**
1514          * @param null|bool|Blob $s
1515          * @return int|string
1516          */
1517         function addQuotes( $s ) {
1518                 if ( is_null( $s ) ) {
1519                         return 'NULL';
1520                 } elseif ( is_bool( $s ) ) {
1521                         return intval( $s );
1522                 } elseif ( $s instanceof Blob ) {
1523                         return "'" . $s->fetch( $s ) . "'";
1524                 }
1525
1526                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1527         }
1528
1529         /**
1530          * Postgres specific version of replaceVars.
1531          * Calls the parent version in Database.php
1532          *
1533          * @param string $ins SQL string, read from a stream (usually tables.sql)
1534          * @return string SQL string
1535          */
1536         protected function replaceVars( $ins ) {
1537                 $ins = parent::replaceVars( $ins );
1538
1539                 if ( $this->numericVersion >= 8.3 ) {
1540                         // Thanks for not providing backwards-compatibility, 8.3
1541                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1542                 }
1543
1544                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1545                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1546                 }
1547
1548                 return $ins;
1549         }
1550
1551         /**
1552          * Various select options
1553          *
1554          * @param array $options An associative array of options to be turned into
1555          *   an SQL query, valid keys are listed in the function.
1556          * @return array
1557          */
1558         function makeSelectOptions( $options ) {
1559                 $preLimitTail = $postLimitTail = '';
1560                 $startOpts = $useIndex = '';
1561
1562                 $noKeyOptions = array();
1563                 foreach ( $options as $key => $option ) {
1564                         if ( is_numeric( $key ) ) {
1565                                 $noKeyOptions[$option] = true;
1566                         }
1567                 }
1568
1569                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1570
1571                 $preLimitTail .= $this->makeOrderBy( $options );
1572
1573                 //if ( isset( $options['LIMIT'] ) ) {
1574                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1575                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1576                 //              : false );
1577                 //}
1578
1579                 if ( isset( $options['FOR UPDATE'] ) ) {
1580                         $postLimitTail .= ' FOR UPDATE OF ' .
1581                                 implode( ', ', array_map( array( &$this, 'tableName' ), $options['FOR UPDATE'] ) );
1582                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1583                         $postLimitTail .= ' FOR UPDATE';
1584                 }
1585
1586                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1587                         $startOpts .= 'DISTINCT';
1588                 }
1589
1590                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1591         }
1592
1593         function getDBname() {
1594                 return $this->mDBname;
1595         }
1596
1597         function getServer() {
1598                 return $this->mServer;
1599         }
1600
1601         function buildConcat( $stringList ) {
1602                 return implode( ' || ', $stringList );
1603         }
1604
1605         public function buildGroupConcatField(
1606                 $delimiter, $table, $field, $conds = '', $options = array(), $join_conds = array()
1607         ) {
1608                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1609
1610                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
1611         }
1612
1613         public function getSearchEngine() {
1614                 return 'SearchPostgres';
1615         }
1616
1617         public function streamStatementEnd( &$sql, &$newLine ) {
1618                 # Allow dollar quoting for function declarations
1619                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1620                         if ( $this->delimiter ) {
1621                                 $this->delimiter = false;
1622                         } else {
1623                                 $this->delimiter = ';';
1624                         }
1625                 }
1626
1627                 return parent::streamStatementEnd( $sql, $newLine );
1628         }
1629
1630         /**
1631          * Check to see if a named lock is available. This is non-blocking.
1632          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1633          *
1634          * @param string $lockName Name of lock to poll
1635          * @param string $method Name of method calling us
1636          * @return bool
1637          * @since 1.20
1638          */
1639         public function lockIsFree( $lockName, $method ) {
1640                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1641                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1642                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1643                 $row = $this->fetchObject( $result );
1644
1645                 return ( $row->lockstatus === 't' );
1646         }
1647
1648         /**
1649          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1650          * @param string $lockName
1651          * @param string $method
1652          * @param int $timeout
1653          * @return bool
1654          */
1655         public function lock( $lockName, $method, $timeout = 5 ) {
1656                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1657                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1658                         $result = $this->query(
1659                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1660                         $row = $this->fetchObject( $result );
1661                         if ( $row->lockstatus === 't' ) {
1662                                 return true;
1663                         } else {
1664                                 sleep( 1 );
1665                         }
1666                 }
1667                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1668
1669                 return false;
1670         }
1671
1672         /**
1673          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1674          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1675          * @param string $lockName
1676          * @param string $method
1677          * @return bool
1678          */
1679         public function unlock( $lockName, $method ) {
1680                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1681                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1682                 $row = $this->fetchObject( $result );
1683
1684                 return ( $row->lockstatus === 't' );
1685         }
1686
1687         /**
1688          * @param string $lockName
1689          * @return string Integer
1690          */
1691         private function bigintFromLockName( $lockName ) {
1692                 return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1693         }
1694 } // end DatabasePostgres class