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          */
 121         function defaultValue() {
 122                 if ( $this->has_default ) {
 123                         return $this->default;
 124                 } else {
 125                         return false;
 126                 }
 127         }
 128 }
 129
 130 /**
 131  * Used to debug transaction processing
 132  * Only used if $wgDebugDBTransactions is true
 133  *
 134  * @since 1.19
 135  * @ingroup Database
 136  */
 137 class PostgresTransactionState {
 138         private static $WATCHED = array(
 139                 array(
 140                         "desc" => "%s: Connection state changed from %s -> %s\n",
 141                         "states" => array(
 142                                 PGSQL_CONNECTION_OK => "OK",
 143                                 PGSQL_CONNECTION_BAD => "BAD"
 144                         )
 145                 ),
 146                 array(
 147                         "desc" => "%s: Transaction state changed from %s -> %s\n",
 148                         "states" => array(
 149                                 PGSQL_TRANSACTION_IDLE => "IDLE",
 150                                 PGSQL_TRANSACTION_ACTIVE => "ACTIVE",
 151                                 PGSQL_TRANSACTION_INTRANS => "TRANS",
 152                                 PGSQL_TRANSACTION_INERROR => "ERROR",
 153                                 PGSQL_TRANSACTION_UNKNOWN => "UNKNOWN"
 154                         )
 155                 )
 156         );
 157
 158         /** @var array */
 159         private $mNewState;
 160
 161         /** @var array */
 162         private $mCurrentState;
 163
 164         public function __construct( $conn ) {
 165                 $this->mConn = $conn;
 166                 $this->update();
 167                 $this->mCurrentState = $this->mNewState;
 168         }
 169
 170         public function update() {
 171                 $this->mNewState = array(
 172                         pg_connection_status( $this->mConn ),
 173                         pg_transaction_status( $this->mConn )
 174                 );
 175         }
 176
 177         public function check() {
 178                 global $wgDebugDBTransactions;
 179                 $this->update();
 180                 if ( $wgDebugDBTransactions ) {
 181                         if ( $this->mCurrentState !== $this->mNewState ) {
 182                                 $old = reset( $this->mCurrentState );
 183                                 $new = reset( $this->mNewState );
 184                                 foreach ( self::$WATCHED as $watched ) {
 185                                         if ( $old !== $new ) {
 186                                                 $this->log_changed( $old, $new, $watched );
 187                                         }
 188                                         $old = next( $this->mCurrentState );
 189                                         $new = next( $this->mNewState );
 190                                 }
 191                         }
 192                 }
 193                 $this->mCurrentState = $this->mNewState;
 194         }
 195
 196         protected function describe_changed( $status, $desc_table ) {
 197                 if ( isset( $desc_table[$status] ) ) {
 198                         return $desc_table[$status];
 199                 } else {
 200                         return "STATUS " . $status;
 201                 }
 202         }
 203
 204         protected function log_changed( $old, $new, $watched ) {
 205                 wfDebug( sprintf( $watched["desc"],
 206                         $this->mConn,
 207                         $this->describe_changed( $old, $watched["states"] ),
 208                         $this->describe_changed( $new, $watched["states"] )
 209                 ) );
 210         }
 211 }
 212
 213 /**
 214  * Manage savepoints within a transaction
 215  * @ingroup Database
 216  * @since 1.19
 217  */
 218 class SavepointPostgres {
 219         /** @var DatabaseBase Establish a savepoint within a transaction */
 220         protected $dbw;
 221         protected $id;
 222         protected $didbegin;
 223
 224         /**
 225          * @param DatabaseBase $dbw
 226          * @param int $id
 227          */
 228         public function __construct( $dbw, $id ) {
 229                 $this->dbw = $dbw;
 230                 $this->id = $id;
 231                 $this->didbegin = false;
 232                 /* If we are not in a transaction, we need to be for savepoint trickery */
 233                 if ( !$dbw->trxLevel() ) {
 234                         $dbw->begin( "FOR SAVEPOINT" );
 235                         $this->didbegin = true;
 236                 }
 237         }
 238
 239         public function __destruct() {
 240                 if ( $this->didbegin ) {
 241                         $this->dbw->rollback();
 242                         $this->didbegin = false;
 243                 }
 244         }
 245
 246         public function commit() {
 247                 if ( $this->didbegin ) {
 248                         $this->dbw->commit();
 249                         $this->didbegin = false;
 250                 }
 251         }
 252
 253         protected function query( $keyword, $msg_ok, $msg_failed ) {
 254                 global $wgDebugDBTransactions;
 255                 if ( $this->dbw->doQuery( $keyword . " " . $this->id ) !== false ) {
 256                         if ( $wgDebugDBTransactions ) {
 257                                 wfDebug( sprintf( $msg_ok, $this->id ) );
 258                         }
 259                 } else {
 260                         wfDebug( sprintf( $msg_failed, $this->id ) );
 261                 }
 262         }
 263
 264         public function savepoint() {
 265                 $this->query( "SAVEPOINT",
 266                         "Transaction state: savepoint \"%s\" established.\n",
 267                         "Transaction state: establishment of savepoint \"%s\" FAILED.\n"
 268                 );
 269         }
 270
 271         public function release() {
 272                 $this->query( "RELEASE",
 273                         "Transaction state: savepoint \"%s\" released.\n",
 274                         "Transaction state: release of savepoint \"%s\" FAILED.\n"
 275                 );
 276         }
 277
 278         public function rollback() {
 279                 $this->query( "ROLLBACK TO",
 280                         "Transaction state: savepoint \"%s\" rolled back.\n",
 281                         "Transaction state: rollback of savepoint \"%s\" FAILED.\n"
 282                 );
 283         }
 284
 285         public function __toString() {
 286                 return (string)$this->id;
 287         }
 288 }
 289
 290 /**
 291  * @ingroup Database
 292  */
 293 class DatabasePostgres extends DatabaseBase {
 294         /** @var resource */
 295         protected $mLastResult = null;
 296
 297         /** @var int The number of rows affected as an integer */
 298         protected $mAffectedRows = null;
 299
 300         /** @var int */
 301         private $mInsertId = null;
 302
 303         /** @var float|string */
 304         private $numericVersion = null;
 305
 306         /** @var string Connect string to open a PostgreSQL connection */
 307         private $connectString;
 308
 309         /** @var PostgresTransactionState */
 310         private $mTransactionState;
 311
 312         /** @var string */
 313         private $mCoreSchema;
 314
 315         function getType() {
 316                 return 'postgres';
 317         }
 318
 319         function cascadingDeletes() {
 320                 return true;
 321         }
 322
 323         function cleanupTriggers() {
 324                 return true;
 325         }
 326
 327         function strictIPs() {
 328                 return true;
 329         }
 330
 331         function realTimestamps() {
 332                 return true;
 333         }
 334
 335         function implicitGroupby() {
 336                 return false;
 337         }
 338
 339         function implicitOrderby() {
 340                 return false;
 341         }
 342
 343         function searchableIPs() {
 344                 return true;
 345         }
 346
 347         function functionalIndexes() {
 348                 return true;
 349         }
 350
 351         function hasConstraint( $name ) {
 352                 $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
 353                         "WHERE c.connamespace = n.oid AND conname = '" .
 354                         pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" .
 355                         pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 356                 $res = $this->doQuery( $sql );
 357
 358                 return $this->numRows( $res );
 359         }
 360
 361         /**
 362          * Usually aborts on failure
 363          * @param string $server
 364          * @param string $user
 365          * @param string $password
 366          * @param string $dbName
 367          * @throws DBConnectionError|Exception
 368          * @return DatabaseBase|null
 369          */
 370         function open( $server, $user, $password, $dbName ) {
 371                 # Test for Postgres support, to avoid suppressed fatal error
 372                 if ( !function_exists( 'pg_connect' ) ) {
 373                         throw new DBConnectionError(
 374                                 $this,
 375                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
 376                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
 377                                 "webserver and database)\n"
 378                         );
 379                 }
 380
 381                 global $wgDBport;
 382
 383                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 384                         return null;
 385                 }
 386
 387                 $this->mServer = $server;
 388                 $port = $wgDBport;
 389                 $this->mUser = $user;
 390                 $this->mPassword = $password;
 391                 $this->mDBname = $dbName;
 392
 393                 $connectVars = array(
 394                         'dbname' => $dbName,
 395                         'user' => $user,
 396                         'password' => $password
 397                 );
 398                 if ( $server != false && $server != '' ) {
 399                         $connectVars['host'] = $server;
 400                 }
 401                 if ( $port != false && $port != '' ) {
 402                         $connectVars['port'] = $port;
 403                 }
 404                 if ( $this->mFlags & DBO_SSL ) {
 405                         $connectVars['sslmode'] = 1;
 406                 }
 407
 408                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 409                 $this->close();
 410                 $this->installErrorHandler();
 411
 412                 try {
 413                         $this->mConn = pg_connect( $this->connectString );
 414                 } catch ( Exception $ex ) {
 415                         $this->restoreErrorHandler();
 416                         throw $ex;
 417                 }
 418
 419                 $phpError = $this->restoreErrorHandler();
 420
 421                 if ( !$this->mConn ) {
 422                         wfDebug( "DB connection error\n" );
 423                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " .
 424                                 substr( $password, 0, 3 ) . "...\n" );
 425                         wfDebug( $this->lastError() . "\n" );
 426                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 427                 }
 428
 429                 $this->mOpened = true;
 430                 $this->mTransactionState = new PostgresTransactionState( $this->mConn );
 431
 432                 global $wgCommandLineMode;
 433                 # If called from the command-line (e.g. importDump), only show errors
 434                 if ( $wgCommandLineMode ) {
 435                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 436                 }
 437
 438                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 439                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 440                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 441                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 442                 if ( $this->getServerVersion() >= 9.0 ) {
 443                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 444                 }
 445
 446                 global $wgDBmwschema;
 447                 $this->determineCoreSchema( $wgDBmwschema );
 448
 449                 return $this->mConn;
 450         }
 451
 452         /**
 453          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 454          * DB name doesn't match the open connection, open a new one
 455          * @param string $db
 456          * @return bool
 457          */
 458         function selectDB( $db ) {
 459                 if ( $this->mDBname !== $db ) {
 460                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 461                 } else {
 462                         return true;
 463                 }
 464         }
 465
 466         function makeConnectionString( $vars ) {
 467                 $s = '';
 468                 foreach ( $vars as $name => $value ) {
 469                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 470                 }
 471
 472                 return $s;
 473         }
 474
 475         /**
 476          * Closes a database connection, if it is open
 477          * Returns success, true if already closed
 478          * @return bool
 479          */
 480         protected function closeConnection() {
 481                 return pg_close( $this->mConn );
 482         }
 483
 484         public function doQuery( $sql ) {
 485                 if ( function_exists( 'mb_convert_encoding' ) ) {
 486                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 487                 }
 488                 $this->mTransactionState->check();
 489                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 490                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 491                 }
 492                 $this->mLastResult = pg_get_result( $this->mConn );
 493                 $this->mTransactionState->check();
 494                 $this->mAffectedRows = null;
 495                 if ( pg_result_error( $this->mLastResult ) ) {
 496                         return false;
 497                 }
 498
 499                 return $this->mLastResult;
 500         }
 501
 502         protected function dumpError() {
 503                 $diags = array(
 504                         PGSQL_DIAG_SEVERITY,
 505                         PGSQL_DIAG_SQLSTATE,
 506                         PGSQL_DIAG_MESSAGE_PRIMARY,
 507                         PGSQL_DIAG_MESSAGE_DETAIL,
 508                         PGSQL_DIAG_MESSAGE_HINT,
 509                         PGSQL_DIAG_STATEMENT_POSITION,
 510                         PGSQL_DIAG_INTERNAL_POSITION,
 511                         PGSQL_DIAG_INTERNAL_QUERY,
 512                         PGSQL_DIAG_CONTEXT,
 513                         PGSQL_DIAG_SOURCE_FILE,
 514                         PGSQL_DIAG_SOURCE_LINE,
 515                         PGSQL_DIAG_SOURCE_FUNCTION
 516                 );
 517                 foreach ( $diags as $d ) {
 518                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n",
 519                                 $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 520                 }
 521         }
 522
 523         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 524                 if ( $tempIgnore ) {
 525                         /* Check for constraint violation */
 526                         if ( $errno === '23505' ) {
 527                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 528
 529                                 return;
 530                         }
 531                 }
 532                 /* Transaction stays in the ERROR state until rolledback */
 533                 if ( $this->mTrxLevel ) {
 534                         $this->rollback( __METHOD__ );
 535                 };
 536                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 537         }
 538
 539         function queryIgnore( $sql, $fname = __METHOD__ ) {
 540                 return $this->query( $sql, $fname, true );
 541         }
 542
 543         /**
 544          * @param stdClass|ResultWrapper $res
 545          * @throws DBUnexpectedError
 546          */
 547         function freeResult( $res ) {
 548                 if ( $res instanceof ResultWrapper ) {
 549                         $res = $res->result;
 550                 }
 551                 wfSuppressWarnings();
 552                 $ok = pg_free_result( $res );
 553                 wfRestoreWarnings();
 554                 if ( !$ok ) {
 555                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 556                 }
 557         }
 558
 559         /**
 560          * @param ResultWrapper|stdClass $res
 561          * @return stdClass
 562          * @throws DBUnexpectedError
 563          */
 564         function fetchObject( $res ) {
 565                 if ( $res instanceof ResultWrapper ) {
 566                         $res = $res->result;
 567                 }
 568                 wfSuppressWarnings();
 569                 $row = pg_fetch_object( $res );
 570                 wfRestoreWarnings();
 571                 # @todo FIXME: HACK HACK HACK HACK debug
 572
 573                 # @todo hashar: not sure if the following test really trigger if the object
 574                 #          fetching failed.
 575                 if ( pg_last_error( $this->mConn ) ) {
 576                         throw new DBUnexpectedError(
 577                                 $this,
 578                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 579                         );
 580                 }
 581
 582                 return $row;
 583         }
 584
 585         function fetchRow( $res ) {
 586                 if ( $res instanceof ResultWrapper ) {
 587                         $res = $res->result;
 588                 }
 589                 wfSuppressWarnings();
 590                 $row = pg_fetch_array( $res );
 591                 wfRestoreWarnings();
 592                 if ( pg_last_error( $this->mConn ) ) {
 593                         throw new DBUnexpectedError(
 594                                 $this,
 595                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 596                         );
 597                 }
 598
 599                 return $row;
 600         }
 601
 602         function numRows( $res ) {
 603                 if ( $res instanceof ResultWrapper ) {
 604                         $res = $res->result;
 605                 }
 606                 wfSuppressWarnings();
 607                 $n = pg_num_rows( $res );
 608                 wfRestoreWarnings();
 609                 if ( pg_last_error( $this->mConn ) ) {
 610                         throw new DBUnexpectedError(
 611                                 $this,
 612                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 613                         );
 614                 }
 615
 616                 return $n;
 617         }
 618
 619         function numFields( $res ) {
 620                 if ( $res instanceof ResultWrapper ) {
 621                         $res = $res->result;
 622                 }
 623
 624                 return pg_num_fields( $res );
 625         }
 626
 627         function fieldName( $res, $n ) {
 628                 if ( $res instanceof ResultWrapper ) {
 629                         $res = $res->result;
 630                 }
 631
 632                 return pg_field_name( $res, $n );
 633         }
 634
 635         /**
 636          * Return the result of the last call to nextSequenceValue();
 637          * This must be called after nextSequenceValue().
 638          *
 639          * @return int|null
 640          */
 641         function insertId() {
 642                 return $this->mInsertId;
 643         }
 644
 645         /**
 646          * @param mixed $res
 647          * @param int $row
 648          * @return bool
 649          */
 650         function dataSeek( $res, $row ) {
 651                 if ( $res instanceof ResultWrapper ) {
 652                         $res = $res->result;
 653                 }
 654
 655                 return pg_result_seek( $res, $row );
 656         }
 657
 658         function lastError() {
 659                 if ( $this->mConn ) {
 660                         if ( $this->mLastResult ) {
 661                                 return pg_result_error( $this->mLastResult );
 662                         } else {
 663                                 return pg_last_error();
 664                         }
 665                 } else {
 666                         return 'No database connection';
 667                 }
 668         }
 669
 670         function lastErrno() {
 671                 if ( $this->mLastResult ) {
 672                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 673                 } else {
 674                         return false;
 675                 }
 676         }
 677
 678         function affectedRows() {
 679                 if ( !is_null( $this->mAffectedRows ) ) {
 680                         // Forced result for simulated queries
 681                         return $this->mAffectedRows;
 682                 }
 683                 if ( empty( $this->mLastResult ) ) {
 684                         return 0;
 685                 }
 686
 687                 return pg_affected_rows( $this->mLastResult );
 688         }
 689
 690         /**
 691          * Estimate rows in dataset
 692          * Returns estimated count, based on EXPLAIN output
 693          * This is not necessarily an accurate estimate, so use sparingly
 694          * Returns -1 if count cannot be found
 695          * Takes same arguments as Database::select()
 696          *
 697          * @param string $table
 698          * @param string $vars
 699          * @param string $conds
 700          * @param string $fname
 701          * @param array $options
 702          * @return int
 703          */
 704         function estimateRowCount( $table, $vars = '*', $conds = '',
 705                 $fname = __METHOD__, $options = array()
 706         ) {
 707                 $options['EXPLAIN'] = true;
 708                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 709                 $rows = -1;
 710                 if ( $res ) {
 711                         $row = $this->fetchRow( $res );
 712                         $count = array();
 713                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 714                                 $rows = $count[1];
 715                         }
 716                 }
 717
 718                 return $rows;
 719         }
 720
 721         /**
 722          * Returns information about an index
 723          * If errors are explicitly ignored, returns NULL on failure
 724          *
 725          * @param string $table
 726          * @param string $index
 727          * @param string $fname
 728          * @return bool|null
 729          */
 730         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 731                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 732                 $res = $this->query( $sql, $fname );
 733                 if ( !$res ) {
 734                         return null;
 735                 }
 736                 foreach ( $res as $row ) {
 737                         if ( $row->indexname == $this->indexName( $index ) ) {
 738                                 return $row;
 739                         }
 740                 }
 741
 742                 return false;
 743         }
 744
 745         /**
 746          * Returns is of attributes used in index
 747          *
 748          * @since 1.19
 749          * @param string $index
 750          * @param bool|string $schema
 751          * @return array
 752          */
 753         function indexAttributes( $index, $schema = false ) {
 754                 if ( $schema === false ) {
 755                         $schema = $this->getCoreSchema();
 756                 }
 757                 /*
 758                  * A subquery would be not needed if we didn't care about the order
 759                  * of attributes, but we do
 760                  */
 761                 $sql = <<<__INDEXATTR__
 762
 763                         SELECT opcname,
 764                                 attname,
 765                                 i.indoption[s.g] as option,
 766                                 pg_am.amname
 767                         FROM
 768                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 769                                         FROM
 770                                                 pg_index isub
 771                                         JOIN pg_class cis
 772                                                 ON cis.oid=isub.indexrelid
 773                                         JOIN pg_namespace ns
 774                                                 ON cis.relnamespace = ns.oid
 775                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 776                                 pg_attribute,
 777                                 pg_opclass opcls,
 778                                 pg_am,
 779                                 pg_class ci
 780                                 JOIN pg_index i
 781                                         ON ci.oid=i.indexrelid
 782                                 JOIN pg_class ct
 783                                         ON ct.oid = i.indrelid
 784                                 JOIN pg_namespace n
 785                                         ON ci.relnamespace = n.oid
 786                                 WHERE
 787                                         ci.relname='$index' AND n.nspname='$schema'
 788                                         AND     attrelid = ct.oid
 789                                         AND     i.indkey[s.g] = attnum
 790                                         AND     i.indclass[s.g] = opcls.oid
 791                                         AND     pg_am.oid = opcls.opcmethod
 792 __INDEXATTR__;
 793                 $res = $this->query( $sql, __METHOD__ );
 794                 $a = array();
 795                 if ( $res ) {
 796                         foreach ( $res as $row ) {
 797                                 $a[] = array(
 798                                         $row->attname,
 799                                         $row->opcname,
 800                                         $row->amname,
 801                                         $row->option );
 802                         }
 803                 } else {
 804                         return null;
 805                 }
 806
 807                 return $a;
 808         }
 809
 810         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 811                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 812                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 813                         $this->strencode( $this->indexName( $index ) ) .
 814                         ")'";
 815                 $res = $this->query( $sql, $fname );
 816                 if ( !$res ) {
 817                         return null;
 818                 }
 819
 820                 return $res->numRows() > 0;
 821         }
 822
 823         /**
 824          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 825          * to the parent function to get the actual SQL text.
 826          *
 827          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 828          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 829          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 830          *
 831          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 832          */
 833         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 834                 $options = array(), $join_conds = array()
 835         ) {
 836                 if ( is_array( $options ) ) {
 837                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 838                         if ( $forUpdateKey !== false && $join_conds ) {
 839                                 unset( $options[$forUpdateKey] );
 840
 841                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 842                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 843                                                 $options['FOR UPDATE'][] = $table_cond;
 844                                         }
 845                                 }
 846                         }
 847
 848                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 849                                 unset( $options['ORDER BY'] );
 850                         }
 851                 }
 852
 853                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 854         }
 855
 856         /**
 857          * INSERT wrapper, inserts an array into a table
 858          *
 859          * $args may be a single associative array, or an array of these with numeric keys,
 860          * for multi-row insert (Postgres version 8.2 and above only).
 861          *
 862          * @param string $table Name of the table to insert to.
 863          * @param array $args Items to insert into the table.
 864          * @param string $fname Name of the function, for profiling
 865          * @param array|string $options String or array. Valid options: IGNORE
 866          * @return bool Success of insert operation. IGNORE always returns true.
 867          */
 868         function insert( $table, $args, $fname = __METHOD__, $options = array() ) {
 869                 if ( !count( $args ) ) {
 870                         return true;
 871                 }
 872
 873                 $table = $this->tableName( $table );
 874                 if ( !isset( $this->numericVersion ) ) {
 875                         $this->getServerVersion();
 876                 }
 877
 878                 if ( !is_array( $options ) ) {
 879                         $options = array( $options );
 880                 }
 881
 882                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 883                         $multi = true;
 884                         $keys = array_keys( $args[0] );
 885                 } else {
 886                         $multi = false;
 887                         $keys = array_keys( $args );
 888                 }
 889
 890                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 891                 $savepoint = null;
 892                 if ( in_array( 'IGNORE', $options ) ) {
 893                         $savepoint = new SavepointPostgres( $this, 'mw' );
 894                         $olde = error_reporting( 0 );
 895                         // For future use, we may want to track the number of actual inserts
 896                         // Right now, insert (all writes) simply return true/false
 897                         $numrowsinserted = 0;
 898                 }
 899
 900                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 901
 902                 if ( $multi ) {
 903                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 904                                 $first = true;
 905                                 foreach ( $args as $row ) {
 906                                         if ( $first ) {
 907                                                 $first = false;
 908                                         } else {
 909                                                 $sql .= ',';
 910                                         }
 911                                         $sql .= '(' . $this->makeList( $row ) . ')';
 912                                 }
 913                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 914                         } else {
 915                                 $res = true;
 916                                 $origsql = $sql;
 917                                 foreach ( $args as $row ) {
 918                                         $tempsql = $origsql;
 919                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 920
 921                                         if ( $savepoint ) {
 922                                                 $savepoint->savepoint();
 923                                         }
 924
 925                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 926
 927                                         if ( $savepoint ) {
 928                                                 $bar = pg_last_error();
 929                                                 if ( $bar != false ) {
 930                                                         $savepoint->rollback();
 931                                                 } else {
 932                                                         $savepoint->release();
 933                                                         $numrowsinserted++;
 934                                                 }
 935                                         }
 936
 937                                         // If any of them fail, we fail overall for this function call
 938                                         // Note that this will be ignored if IGNORE is set
 939                                         if ( !$tempres ) {
 940                                                 $res = false;
 941                                         }
 942                                 }
 943                         }
 944                 } else {
 945                         // Not multi, just a lone insert
 946                         if ( $savepoint ) {
 947                                 $savepoint->savepoint();
 948                         }
 949
 950                         $sql .= '(' . $this->makeList( $args ) . ')';
 951                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 952                         if ( $savepoint ) {
 953                                 $bar = pg_last_error();
 954                                 if ( $bar != false ) {
 955                                         $savepoint->rollback();
 956                                 } else {
 957                                         $savepoint->release();
 958                                         $numrowsinserted++;
 959                                 }
 960                         }
 961                 }
 962                 if ( $savepoint ) {
 963                         error_reporting( $olde );
 964                         $savepoint->commit();
 965
 966                         // Set the affected row count for the whole operation
 967                         $this->mAffectedRows = $numrowsinserted;
 968
 969                         // IGNORE always returns true
 970                         return true;
 971                 }
 972
 973                 return $res;
 974         }
 975
 976         /**
 977          * INSERT SELECT wrapper
 978          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 979          * Source items may be literals rather then field names, but strings should
 980          * be quoted with Database::addQuotes()
 981          * $conds may be "*" to copy the whole table
 982          * srcTable may be an array of tables.
 983          * @todo FIXME: Implement this a little better (seperate select/insert)?
 984          *
 985          * @param string $destTable
 986          * @param array|string $srcTable
 987          * @param array $varMap
 988          * @param array $conds
 989          * @param string $fname
 990          * @param array $insertOptions
 991          * @param array $selectOptions
 992          * @return bool
 993          */
 994         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 995                 $insertOptions = array(), $selectOptions = array() ) {
 996                 $destTable = $this->tableName( $destTable );
 997
 998                 if ( !is_array( $insertOptions ) ) {
 999                         $insertOptions = array( $insertOptions );
1000                 }
1001
1002                 /*
1003                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
1004                  * Ignore LOW PRIORITY option, since it is MySQL-specific
1005                  */
1006                 $savepoint = null;
1007                 if ( in_array( 'IGNORE', $insertOptions ) ) {
1008                         $savepoint = new SavepointPostgres( $this, 'mw' );
1009                         $olde = error_reporting( 0 );
1010                         $numrowsinserted = 0;
1011                         $savepoint->savepoint();
1012                 }
1013
1014                 if ( !is_array( $selectOptions ) ) {
1015                         $selectOptions = array( $selectOptions );
1016                 }
1017                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
1018                 if ( is_array( $srcTable ) ) {
1019                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
1020                 } else {
1021                         $srcTable = $this->tableName( $srcTable );
1022                 }
1023
1024                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
1025                         " SELECT $startOpts " . implode( ',', $varMap ) .
1026                         " FROM $srcTable $useIndex";
1027
1028                 if ( $conds != '*' ) {
1029                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
1030                 }
1031
1032                 $sql .= " $tailOpts";
1033
1034                 $res = (bool)$this->query( $sql, $fname, $savepoint );
1035                 if ( $savepoint ) {
1036                         $bar = pg_last_error();
1037                         if ( $bar != false ) {
1038                                 $savepoint->rollback();
1039                         } else {
1040                                 $savepoint->release();
1041                                 $numrowsinserted++;
1042                         }
1043                         error_reporting( $olde );
1044                         $savepoint->commit();
1045
1046                         // Set the affected row count for the whole operation
1047                         $this->mAffectedRows = $numrowsinserted;
1048
1049                         // IGNORE always returns true
1050                         return true;
1051                 }
1052
1053                 return $res;
1054         }
1055
1056         function tableName( $name, $format = 'quoted' ) {
1057                 # Replace reserved words with better ones
1058                 switch ( $name ) {
1059                         case 'user':
1060                                 return $this->realTableName( 'mwuser', $format );
1061                         case 'text':
1062                                 return $this->realTableName( 'pagecontent', $format );
1063                         default:
1064                                 return $this->realTableName( $name, $format );
1065                 }
1066         }
1067
1068         /* Don't cheat on installer */
1069         function realTableName( $name, $format = 'quoted' ) {
1070                 return parent::tableName( $name, $format );
1071         }
1072
1073         /**
1074          * Return the next in a sequence, save the value for retrieval via insertId()
1075          *
1076          * @param string $seqName
1077          * @return int|null
1078          */
1079         function nextSequenceValue( $seqName ) {
1080                 $safeseq = str_replace( "'", "''", $seqName );
1081                 $res = $this->query( "SELECT nextval('$safeseq')" );
1082                 $row = $this->fetchRow( $res );
1083                 $this->mInsertId = $row[0];
1084
1085                 return $this->mInsertId;
1086         }
1087
1088         /**
1089          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
1090          *
1091          * @param string $seqName
1092          * @return int
1093          */
1094         function currentSequenceValue( $seqName ) {
1095                 $safeseq = str_replace( "'", "''", $seqName );
1096                 $res = $this->query( "SELECT currval('$safeseq')" );
1097                 $row = $this->fetchRow( $res );
1098                 $currval = $row[0];
1099
1100                 return $currval;
1101         }
1102
1103         # Returns the size of a text field, or -1 for "unlimited"
1104         function textFieldSize( $table, $field ) {
1105                 $table = $this->tableName( $table );
1106                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1107                         FROM pg_class c, pg_attribute a, pg_type t
1108                         WHERE relname='$table' AND a.attrelid=c.oid AND
1109                                 a.atttypid=t.oid and a.attname='$field'";
1110                 $res = $this->query( $sql );
1111                 $row = $this->fetchObject( $res );
1112                 if ( $row->ftype == 'varchar' ) {
1113                         $size = $row->size - 4;
1114                 } else {
1115                         $size = $row->size;
1116                 }
1117
1118                 return $size;
1119         }
1120
1121         function limitResult( $sql, $limit, $offset = false ) {
1122                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1123         }
1124
1125         function wasDeadlock() {
1126                 return $this->lastErrno() == '40P01';
1127         }
1128
1129         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1130                 $newName = $this->addIdentifierQuotes( $newName );
1131                 $oldName = $this->addIdentifierQuotes( $oldName );
1132
1133                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1134                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1135         }
1136
1137         function listTables( $prefix = null, $fname = __METHOD__ ) {
1138                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1139                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1140                 $endArray = array();
1141
1142                 foreach ( $result as $table ) {
1143                         $vars = get_object_vars( $table );
1144                         $table = array_pop( $vars );
1145                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1146                                 $endArray[] = $table;
1147                         }
1148                 }
1149
1150                 return $endArray;
1151         }
1152
1153         function timestamp( $ts = 0 ) {
1154                 return wfTimestamp( TS_POSTGRES, $ts );
1155         }
1156
1157         /**
1158          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1159          * to http://www.php.net/manual/en/ref.pgsql.php
1160          *
1161          * Parsing a postgres array can be a tricky problem, he's my
1162          * take on this, it handles multi-dimensional arrays plus
1163          * escaping using a nasty regexp to determine the limits of each
1164          * data-item.
1165          *
1166          * This should really be handled by PHP PostgreSQL module
1167          *
1168          * @since 1.19
1169          * @param string $text Postgreql array returned in a text form like {a,b}
1170          * @param string $output
1171          * @param int $limit
1172          * @param int $offset
1173          * @return string
1174          */
1175         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1176                 if ( false === $limit ) {
1177                         $limit = strlen( $text ) - 1;
1178                         $output = array();
1179                 }
1180                 if ( '{}' == $text ) {
1181                         return $output;
1182                 }
1183                 do {
1184                         if ( '{' != $text[$offset] ) {
1185                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1186                                         $text, $match, 0, $offset );
1187                                 $offset += strlen( $match[0] );
1188                                 $output[] = ( '"' != $match[1][0]
1189                                         ? $match[1]
1190                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1191                                 if ( '},' == $match[3] ) {
1192                                         return $output;
1193                                 }
1194                         } else {
1195                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1196                         }
1197                 } while ( $limit > $offset );
1198
1199                 return $output;
1200         }
1201
1202         /**
1203          * Return aggregated value function call
1204          * @param array $valuedata
1205          * @param string $valuename
1206          * @return array
1207          */
1208         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1209                 return $valuedata;
1210         }
1211
1212         /**
1213          * @return string Wikitext of a link to the server software's web site
1214          */
1215         public function getSoftwareLink() {
1216                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1217         }
1218
1219         /**
1220          * Return current schema (executes SELECT current_schema())
1221          * Needs transaction
1222          *
1223          * @since 1.19
1224          * @return string Default schema for the current session
1225          */
1226         function getCurrentSchema() {
1227                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1228                 $row = $this->fetchRow( $res );
1229
1230                 return $row[0];
1231         }
1232
1233         /**
1234          * Return list of schemas which are accessible without schema name
1235          * This is list does not contain magic keywords like "$user"
1236          * Needs transaction
1237          *
1238          * @see getSearchPath()
1239          * @see setSearchPath()
1240          * @since 1.19
1241          * @return array List of actual schemas for the current sesson
1242          */
1243         function getSchemas() {
1244                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1245                 $row = $this->fetchRow( $res );
1246                 $schemas = array();
1247
1248                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1249
1250                 return $this->pg_array_parse( $row[0], $schemas );
1251         }
1252
1253         /**
1254          * Return search patch for schemas
1255          * This is different from getSchemas() since it contain magic keywords
1256          * (like "$user").
1257          * Needs transaction
1258          *
1259          * @since 1.19
1260          * @return array How to search for table names schemas for the current user
1261          */
1262         function getSearchPath() {
1263                 $res = $this->query( "SHOW search_path", __METHOD__ );
1264                 $row = $this->fetchRow( $res );
1265
1266                 /* PostgreSQL returns SHOW values as strings */
1267
1268                 return explode( ",", $row[0] );
1269         }
1270
1271         /**
1272          * Update search_path, values should already be sanitized
1273          * Values may contain magic keywords like "$user"
1274          * @since 1.19
1275          *
1276          * @param array $search_path List of schemas to be searched by default
1277          */
1278         function setSearchPath( $search_path ) {
1279                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1280         }
1281
1282         /**
1283          * Determine default schema for MediaWiki core
1284          * Adjust this session schema search path if desired schema exists
1285          * and is not alread there.
1286          *
1287          * We need to have name of the core schema stored to be able
1288          * to query database metadata.
1289          *
1290          * This will be also called by the installer after the schema is created
1291          *
1292          * @since 1.19
1293          *
1294          * @param string $desiredSchema
1295          */
1296         function determineCoreSchema( $desiredSchema ) {
1297                 $this->begin( __METHOD__ );
1298                 if ( $this->schemaExists( $desiredSchema ) ) {
1299                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1300                                 $this->mCoreSchema = $desiredSchema;
1301                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1302                         } else {
1303                                 /**
1304                                  * Prepend our schema (e.g. 'mediawiki') in front
1305                                  * of the search path
1306                                  * Fixes bug 15816
1307                                  */
1308                                 $search_path = $this->getSearchPath();
1309                                 array_unshift( $search_path,
1310                                         $this->addIdentifierQuotes( $desiredSchema ) );
1311                                 $this->setSearchPath( $search_path );
1312                                 $this->mCoreSchema = $desiredSchema;
1313                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1314                         }
1315                 } else {
1316                         $this->mCoreSchema = $this->getCurrentSchema();
1317                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1318                                 $this->mCoreSchema . "\"\n" );
1319                 }
1320                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1321                 $this->commit( __METHOD__ );
1322         }
1323
1324         /**
1325          * Return schema name fore core MediaWiki tables
1326          *
1327          * @since 1.19
1328          * @return string Core schema name
1329          */
1330         function getCoreSchema() {
1331                 return $this->mCoreSchema;
1332         }
1333
1334         /**
1335          * @return string Version information from the database
1336          */
1337         function getServerVersion() {
1338                 if ( !isset( $this->numericVersion ) ) {
1339                         $versionInfo = pg_version( $this->mConn );
1340                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1341                                 // Old client, abort install
1342                                 $this->numericVersion = '7.3 or earlier';
1343                         } elseif ( isset( $versionInfo['server'] ) ) {
1344                                 // Normal client
1345                                 $this->numericVersion = $versionInfo['server'];
1346                         } else {
1347                                 // Bug 16937: broken pgsql extension from PHP<5.3
1348                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1349                         }
1350                 }
1351
1352                 return $this->numericVersion;
1353         }
1354
1355         /**
1356          * Query whether a given relation exists (in the given schema, or the
1357          * default mw one if not given)
1358          * @param string $table
1359          * @param array|string $types
1360          * @param bool|string $schema
1361          * @return bool
1362          */
1363         function relationExists( $table, $types, $schema = false ) {
1364                 if ( !is_array( $types ) ) {
1365                         $types = array( $types );
1366                 }
1367                 if ( !$schema ) {
1368                         $schema = $this->getCoreSchema();
1369                 }
1370                 $table = $this->realTableName( $table, 'raw' );
1371                 $etable = $this->addQuotes( $table );
1372                 $eschema = $this->addQuotes( $schema );
1373                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1374                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1375                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1376                 $res = $this->query( $sql );
1377                 $count = $res ? $res->numRows() : 0;
1378
1379                 return (bool)$count;
1380         }
1381
1382         /**
1383          * For backward compatibility, this function checks both tables and
1384          * views.
1385          * @param string $table
1386          * @param string $fname
1387          * @param bool|string $schema
1388          * @return bool
1389          */
1390         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1391                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1392         }
1393
1394         function sequenceExists( $sequence, $schema = false ) {
1395                 return $this->relationExists( $sequence, 'S', $schema );
1396         }
1397
1398         function triggerExists( $table, $trigger ) {
1399                 $q = <<<SQL
1400         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1401                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1402                           AND tgrelid=pg_class.oid
1403                           AND nspname=%s AND relname=%s AND tgname=%s
1404 SQL;
1405                 $res = $this->query(
1406                         sprintf(
1407                                 $q,
1408                                 $this->addQuotes( $this->getCoreSchema() ),
1409                                 $this->addQuotes( $table ),
1410                                 $this->addQuotes( $trigger )
1411                         )
1412                 );
1413                 if ( !$res ) {
1414                         return null;
1415                 }
1416                 $rows = $res->numRows();
1417
1418                 return $rows;
1419         }
1420
1421         function ruleExists( $table, $rule ) {
1422                 $exists = $this->selectField( 'pg_rules', 'rulename',
1423                         array(
1424                                 'rulename' => $rule,
1425                                 'tablename' => $table,
1426                                 'schemaname' => $this->getCoreSchema()
1427                         )
1428                 );
1429
1430                 return $exists === $rule;
1431         }
1432
1433         function constraintExists( $table, $constraint ) {
1434                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1435                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1436                         $this->addQuotes( $this->getCoreSchema() ),
1437                         $this->addQuotes( $table ),
1438                         $this->addQuotes( $constraint )
1439                 );
1440                 $res = $this->query( $sql );
1441                 if ( !$res ) {
1442                         return null;
1443                 }
1444                 $rows = $res->numRows();
1445
1446                 return $rows;
1447         }
1448
1449         /**
1450          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1451          * @param string $schema
1452          * @return bool
1453          */
1454         function schemaExists( $schema ) {
1455                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1456                         array( 'nspname' => $schema ), __METHOD__ );
1457
1458                 return (bool)$exists;
1459         }
1460
1461         /**
1462          * Returns true if a given role (i.e. user) exists, false otherwise.
1463          * @param string $roleName
1464          * @return bool
1465          */
1466         function roleExists( $roleName ) {
1467                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1468                         array( 'rolname' => $roleName ), __METHOD__ );
1469
1470                 return (bool)$exists;
1471         }
1472
1473         function fieldInfo( $table, $field ) {
1474                 return PostgresField::fromText( $this, $table, $field );
1475         }
1476
1477         /**
1478          * pg_field_type() wrapper
1479          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1480          * @param int $index Field number, starting from 0
1481          * @return string
1482          */
1483         function fieldType( $res, $index ) {
1484                 if ( $res instanceof ResultWrapper ) {
1485                         $res = $res->result;
1486                 }
1487
1488                 return pg_field_type( $res, $index );
1489         }
1490
1491         /**
1492          * @param string $b
1493          * @return Blob
1494          */
1495         function encodeBlob( $b ) {
1496                 return new Blob( pg_escape_bytea( $this->mConn, $b ) );
1497         }
1498
1499         function decodeBlob( $b ) {
1500                 if ( $b instanceof Blob ) {
1501                         $b = $b->fetch();
1502                 }
1503
1504                 return pg_unescape_bytea( $b );
1505         }
1506
1507         function strencode( $s ) { # Should not be called by us
1508                 return pg_escape_string( $this->mConn, $s );
1509         }
1510
1511         /**
1512          * @param null|bool|Blob $s
1513          * @return int|string
1514          */
1515         function addQuotes( $s ) {
1516                 if ( is_null( $s ) ) {
1517                         return 'NULL';
1518                 } elseif ( is_bool( $s ) ) {
1519                         return intval( $s );
1520                 } elseif ( $s instanceof Blob ) {
1521                         return "'" . $s->fetch( $s ) . "'";
1522                 }
1523
1524                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1525         }
1526
1527         /**
1528          * Postgres specific version of replaceVars.
1529          * Calls the parent version in Database.php
1530          *
1531          * @param string $ins SQL string, read from a stream (usually tables.sql)
1532          * @return string SQL string
1533          */
1534         protected function replaceVars( $ins ) {
1535                 $ins = parent::replaceVars( $ins );
1536
1537                 if ( $this->numericVersion >= 8.3 ) {
1538                         // Thanks for not providing backwards-compatibility, 8.3
1539                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1540                 }
1541
1542                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1543                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1544                 }
1545
1546                 return $ins;
1547         }
1548
1549         /**
1550          * Various select options
1551          *
1552          * @param array $options An associative array of options to be turned into
1553          *   an SQL query, valid keys are listed in the function.
1554          * @return array
1555          */
1556         function makeSelectOptions( $options ) {
1557                 $preLimitTail = $postLimitTail = '';
1558                 $startOpts = $useIndex = '';
1559
1560                 $noKeyOptions = array();
1561                 foreach ( $options as $key => $option ) {
1562                         if ( is_numeric( $key ) ) {
1563                                 $noKeyOptions[$option] = true;
1564                         }
1565                 }
1566
1567                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1568
1569                 $preLimitTail .= $this->makeOrderBy( $options );
1570
1571                 //if ( isset( $options['LIMIT'] ) ) {
1572                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1573                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1574                 //              : false );
1575                 //}
1576
1577                 if ( isset( $options['FOR UPDATE'] ) ) {
1578                         $postLimitTail .= ' FOR UPDATE OF ' .
1579                                 implode( ', ', array_map( array( &$this, 'tableName' ), $options['FOR UPDATE'] ) );
1580                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1581                         $postLimitTail .= ' FOR UPDATE';
1582                 }
1583
1584                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1585                         $startOpts .= 'DISTINCT';
1586                 }
1587
1588                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1589         }
1590
1591         function getDBname() {
1592                 return $this->mDBname;
1593         }
1594
1595         function getServer() {
1596                 return $this->mServer;
1597         }
1598
1599         function buildConcat( $stringList ) {
1600                 return implode( ' || ', $stringList );
1601         }
1602
1603         public function buildGroupConcatField(
1604                 $delimiter, $table, $field, $conds = '', $options = array(), $join_conds = array()
1605         ) {
1606                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1607
1608                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
1609         }
1610
1611         public function getSearchEngine() {
1612                 return 'SearchPostgres';
1613         }
1614
1615         public function streamStatementEnd( &$sql, &$newLine ) {
1616                 # Allow dollar quoting for function declarations
1617                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1618                         if ( $this->delimiter ) {
1619                                 $this->delimiter = false;
1620                         } else {
1621                                 $this->delimiter = ';';
1622                         }
1623                 }
1624
1625                 return parent::streamStatementEnd( $sql, $newLine );
1626         }
1627
1628         /**
1629          * Check to see if a named lock is available. This is non-blocking.
1630          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1631          *
1632          * @param string $lockName Name of lock to poll
1633          * @param string $method Name of method calling us
1634          * @return bool
1635          * @since 1.20
1636          */
1637         public function lockIsFree( $lockName, $method ) {
1638                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1639                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1640                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1641                 $row = $this->fetchObject( $result );
1642
1643                 return ( $row->lockstatus === 't' );
1644         }
1645
1646         /**
1647          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1648          * @param string $lockName
1649          * @param string $method
1650          * @param int $timeout
1651          * @return bool
1652          */
1653         public function lock( $lockName, $method, $timeout = 5 ) {
1654                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1655                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1656                         $result = $this->query(
1657                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1658                         $row = $this->fetchObject( $result );
1659                         if ( $row->lockstatus === 't' ) {
1660                                 return true;
1661                         } else {
1662                                 sleep( 1 );
1663                         }
1664                 }
1665                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1666
1667                 return false;
1668         }
1669
1670         /**
1671          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1672          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1673          * @param string $lockName
1674          * @param string $method
1675          * @return bool
1676          */
1677         public function unlock( $lockName, $method ) {
1678                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1679                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1680                 $row = $this->fetchObject( $result );
1681
1682                 return ( $row->lockstatus === 't' );
1683         }
1684
1685         /**
1686          * @param string $lockName
1687          * @return string Integer
1688          */
1689         private function bigintFromLockName( $lockName ) {
1690                 return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1691         }
1692 } // end DatabasePostgres class