includes/db/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 class PostgresField implements Field {
  25         private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname,
  26                 $has_default, $default;
  27
  28         /**
  29          * @param $db DatabaseBase
  30          * @param  $table
  31          * @param  $field
  32          * @return null|PostgresField
  33          */
  34         static function fromText( $db, $table, $field ) {
  35                 $q = <<<SQL
  36 SELECT
  37  attnotnull, attlen, conname AS conname,
  38  atthasdef,
  39  adsrc,
  40  COALESCE(condeferred, 'f') AS deferred,
  41  COALESCE(condeferrable, 'f') AS deferrable,
  42  CASE WHEN typname = 'int2' THEN 'smallint'
  43   WHEN typname = 'int4' THEN 'integer'
  44   WHEN typname = 'int8' THEN 'bigint'
  45   WHEN typname = 'bpchar' THEN 'char'
  46  ELSE typname END AS typname
  47 FROM pg_class c
  48 JOIN pg_namespace n ON (n.oid = c.relnamespace)
  49 JOIN pg_attribute a ON (a.attrelid = c.oid)
  50 JOIN pg_type t ON (t.oid = a.atttypid)
  51 LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
  52 LEFT JOIN pg_attrdef d on c.oid=d.adrelid and a.attnum=d.adnum
  53 WHERE relkind = 'r'
  54 AND nspname=%s
  55 AND relname=%s
  56 AND attname=%s;
  57 SQL;
  58
  59                 $table = $db->tableName( $table, 'raw' );
  60                 $res = $db->query(
  61                         sprintf( $q,
  62                                 $db->addQuotes( $db->getCoreSchema() ),
  63                                 $db->addQuotes( $table ),
  64                                 $db->addQuotes( $field )
  65                         )
  66                 );
  67                 $row = $db->fetchObject( $res );
  68                 if ( !$row ) {
  69                         return null;
  70                 }
  71                 $n = new PostgresField;
  72                 $n->type = $row->typname;
  73                 $n->nullable = ( $row->attnotnull == 'f' );
  74                 $n->name = $field;
  75                 $n->tablename = $table;
  76                 $n->max_length = $row->attlen;
  77                 $n->deferrable = ( $row->deferrable == 't' );
  78                 $n->deferred = ( $row->deferred == 't' );
  79                 $n->conname = $row->conname;
  80                 $n->has_default = ( $row->atthasdef === 't' );
  81                 $n->default = $row->adsrc;
  82                 return $n;
  83         }
  84
  85         function name() {
  86                 return $this->name;
  87         }
  88
  89         function tableName() {
  90                 return $this->tablename;
  91         }
  92
  93         function type() {
  94                 return $this->type;
  95         }
  96
  97         function isNullable() {
  98                 return $this->nullable;
  99         }
 100
 101         function maxLength() {
 102                 return $this->max_length;
 103         }
 104
 105         function is_deferrable() {
 106                 return $this->deferrable;
 107         }
 108
 109         function is_deferred() {
 110                 return $this->deferred;
 111         }
 112
 113         function conname() {
 114                 return $this->conname;
 115         }
 116         /**
 117          * @since 1.19
 118          */
 119         function defaultValue() {
 120                 if ( $this->has_default ) {
 121                         return $this->default;
 122                 } else {
 123                         return false;
 124                 }
 125         }
 126
 127 }
 128
 129 /**
 130  * Used to debug transaction processing
 131  * Only used if $wgDebugDBTransactions is true
 132  *
 133  * @since 1.19
 134  * @ingroup Database
 135  */
 136 class PostgresTransactionState {
 137
 138         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         public function __construct( $conn ) {
 159                 $this->mConn = $conn;
 160                 $this->update();
 161                 $this->mCurrentState = $this->mNewState;
 162         }
 163
 164         public function update() {
 165                 $this->mNewState = array(
 166                         pg_connection_status( $this->mConn ),
 167                         pg_transaction_status( $this->mConn )
 168                 );
 169         }
 170
 171         public function check() {
 172                 global $wgDebugDBTransactions;
 173                 $this->update();
 174                 if ( $wgDebugDBTransactions ) {
 175                         if ( $this->mCurrentState !== $this->mNewState ) {
 176                                 $old = reset( $this->mCurrentState );
 177                                 $new = reset( $this->mNewState );
 178                                 foreach ( self::$WATCHED as $watched ) {
 179                                         if ( $old !== $new ) {
 180                                                 $this->log_changed( $old, $new, $watched );
 181                                         }
 182                                         $old = next( $this->mCurrentState );
 183                                         $new = next( $this->mNewState );
 184
 185                                 }
 186                         }
 187                 }
 188                 $this->mCurrentState = $this->mNewState;
 189         }
 190
 191         protected function describe_changed( $status, $desc_table ) {
 192                 if ( isset( $desc_table[$status] ) ) {
 193                         return $desc_table[$status];
 194                 } else {
 195                         return "STATUS " . $status;
 196                 }
 197         }
 198
 199         protected function log_changed( $old, $new, $watched ) {
 200                 wfDebug( sprintf( $watched["desc"],
 201                         $this->mConn,
 202                         $this->describe_changed( $old, $watched["states"] ),
 203                         $this->describe_changed( $new, $watched["states"] )
 204                 ) );
 205         }
 206 }
 207
 208 /**
 209  * Manage savepoints within a transaction
 210  * @ingroup Database
 211  * @since 1.19
 212  */
 213 class SavepointPostgres {
 214         /**
 215          * Establish a savepoint within a transaction
 216          */
 217         protected $dbw;
 218         protected $id;
 219         protected $didbegin;
 220
 221         public function __construct( $dbw, $id ) {
 222                 $this->dbw = $dbw;
 223                 $this->id = $id;
 224                 $this->didbegin = false;
 225                 /* If we are not in a transaction, we need to be for savepoint trickery */
 226                 if ( !$dbw->trxLevel() ) {
 227                                 $dbw->begin( "FOR SAVEPOINT" );
 228                                 $this->didbegin = true;
 229                 }
 230         }
 231
 232         public function __destruct() {
 233                 if ( $this->didbegin ) {
 234                         $this->dbw->rollback();
 235                         $this->didbegin = false;
 236                 }
 237         }
 238
 239         public function commit() {
 240                 if ( $this->didbegin ) {
 241                         $this->dbw->commit();
 242                         $this->didbegin = false;
 243                 }
 244         }
 245
 246         protected function query( $keyword, $msg_ok, $msg_failed ) {
 247                 global $wgDebugDBTransactions;
 248                 if ( $this->dbw->doQuery( $keyword . " " . $this->id ) !== false ) {
 249                         if ( $wgDebugDBTransactions ) {
 250                                 wfDebug( sprintf ( $msg_ok, $this->id ) );
 251                         }
 252                 } else {
 253                         wfDebug( sprintf ( $msg_failed, $this->id ) );
 254                 }
 255         }
 256
 257         public function savepoint() {
 258                 $this->query( "SAVEPOINT",
 259                         "Transaction state: savepoint \"%s\" established.\n",
 260                         "Transaction state: establishment of savepoint \"%s\" FAILED.\n"
 261                 );
 262         }
 263
 264         public function release() {
 265                 $this->query( "RELEASE",
 266                         "Transaction state: savepoint \"%s\" released.\n",
 267                         "Transaction state: release of savepoint \"%s\" FAILED.\n"
 268                 );
 269         }
 270
 271         public function rollback() {
 272                 $this->query( "ROLLBACK TO",
 273                         "Transaction state: savepoint \"%s\" rolled back.\n",
 274                         "Transaction state: rollback of savepoint \"%s\" FAILED.\n"
 275                 );
 276         }
 277
 278         public function __toString() {
 279                 return (string)$this->id;
 280         }
 281 }
 282
 283 /**
 284  * @ingroup Database
 285  */
 286 class DatabasePostgres extends DatabaseBase {
 287         var $mInsertId = null;
 288         var $mLastResult = null;
 289         var $numeric_version = null;
 290         var $mAffectedRows = null;
 291
 292         function getType() {
 293                 return 'postgres';
 294         }
 295
 296         function cascadingDeletes() {
 297                 return true;
 298         }
 299         function cleanupTriggers() {
 300                 return true;
 301         }
 302         function strictIPs() {
 303                 return true;
 304         }
 305         function realTimestamps() {
 306                 return true;
 307         }
 308         function implicitGroupby() {
 309                 return false;
 310         }
 311         function implicitOrderby() {
 312                 return false;
 313         }
 314         function searchableIPs() {
 315                 return true;
 316         }
 317         function functionalIndexes() {
 318                 return true;
 319         }
 320
 321         function hasConstraint( $name ) {
 322                 $SQL = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n WHERE c.connamespace = n.oid AND conname = '" .
 323                                 pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" . pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 324                 $res = $this->doQuery( $SQL );
 325                 return $this->numRows( $res );
 326         }
 327
 328         /**
 329          * Usually aborts on failure
 330          * @param string $server
 331          * @param string $user
 332          * @param string $password
 333          * @param string $dbName
 334          * @throws DBConnectionError
 335          * @return DatabaseBase|null
 336          */
 337         function open( $server, $user, $password, $dbName ) {
 338                 # Test for Postgres support, to avoid suppressed fatal error
 339                 if ( !function_exists( 'pg_connect' ) ) {
 340                         throw new DBConnectionError( $this, "Postgres functions missing, have you compiled PHP with the --with-pgsql option?\n (Note: if you recently installed PHP, you may need to restart your webserver and database)\n" );
 341                 }
 342
 343                 global $wgDBport;
 344
 345                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 346                         return;
 347                 }
 348
 349                 $this->mServer = $server;
 350                 $port = $wgDBport;
 351                 $this->mUser = $user;
 352                 $this->mPassword = $password;
 353                 $this->mDBname = $dbName;
 354
 355                 $connectVars = array(
 356                         'dbname' => $dbName,
 357                         'user' => $user,
 358                         'password' => $password
 359                 );
 360                 if ( $server != false && $server != '' ) {
 361                         $connectVars['host'] = $server;
 362                 }
 363                 if ( $port != false && $port != '' ) {
 364                         $connectVars['port'] = $port;
 365                 }
 366                 if ( $this->mFlags & DBO_SSL ) {
 367                         $connectVars['sslmode'] = 1;
 368                 }
 369
 370                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 371                 $this->close();
 372                 $this->installErrorHandler();
 373
 374                 try {
 375                         $this->mConn = pg_connect( $this->connectString );
 376                 } catch ( Exception $ex ) {
 377                         $this->restoreErrorHandler();
 378                         throw $ex;
 379                 }
 380
 381                 $phpError = $this->restoreErrorHandler();
 382
 383                 if ( !$this->mConn ) {
 384                         wfDebug( "DB connection error\n" );
 385                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 386                         wfDebug( $this->lastError() . "\n" );
 387                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 388                 }
 389
 390                 $this->mOpened = true;
 391                 $this->mTransactionState = new PostgresTransactionState( $this->mConn );
 392
 393                 global $wgCommandLineMode;
 394                 # If called from the command-line (e.g. importDump), only show errors
 395                 if ( $wgCommandLineMode ) {
 396                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 397                 }
 398
 399                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 400                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 401                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 402                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 403                 if ( $this->getServerVersion() >= 9.0 ) {
 404                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 405                 }
 406
 407                 global $wgDBmwschema;
 408                 $this->determineCoreSchema( $wgDBmwschema );
 409
 410                 return $this->mConn;
 411         }
 412
 413         /**
 414          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 415          * DB name doesn't match the open connection, open a new one
 416          * @return
 417          */
 418         function selectDB( $db ) {
 419                 if ( $this->mDBname !== $db ) {
 420                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 421                 } else {
 422                         return true;
 423                 }
 424         }
 425
 426         function makeConnectionString( $vars ) {
 427                 $s = '';
 428                 foreach ( $vars as $name => $value ) {
 429                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 430                 }
 431                 return $s;
 432         }
 433
 434         /**
 435          * Closes a database connection, if it is open
 436          * Returns success, true if already closed
 437          * @return bool
 438          */
 439         protected function closeConnection() {
 440                 return pg_close( $this->mConn );
 441         }
 442
 443         public function doQuery( $sql ) {
 444                 if ( function_exists( 'mb_convert_encoding' ) ) {
 445                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 446                 }
 447                 $this->mTransactionState->check();
 448                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 449                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 450                 }
 451                 $this->mLastResult = pg_get_result( $this->mConn );
 452                 $this->mTransactionState->check();
 453                 $this->mAffectedRows = null;
 454                 if ( pg_result_error( $this->mLastResult ) ) {
 455                         return false;
 456                 }
 457                 return $this->mLastResult;
 458         }
 459
 460         protected function dumpError() {
 461                 $diags = array( PGSQL_DIAG_SEVERITY,
 462                                 PGSQL_DIAG_SQLSTATE,
 463                                 PGSQL_DIAG_MESSAGE_PRIMARY,
 464                                 PGSQL_DIAG_MESSAGE_DETAIL,
 465                                 PGSQL_DIAG_MESSAGE_HINT,
 466                                 PGSQL_DIAG_STATEMENT_POSITION,
 467                                 PGSQL_DIAG_INTERNAL_POSITION,
 468                                 PGSQL_DIAG_INTERNAL_QUERY,
 469                                 PGSQL_DIAG_CONTEXT,
 470                                 PGSQL_DIAG_SOURCE_FILE,
 471                                 PGSQL_DIAG_SOURCE_LINE,
 472                                 PGSQL_DIAG_SOURCE_FUNCTION );
 473                 foreach ( $diags as $d ) {
 474                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n", $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 475                 }
 476         }
 477
 478         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 479                 /* Transaction stays in the ERROR state until rolledback */
 480                 if ( $tempIgnore ) {
 481                         /* Check for constraint violation */
 482                         if ( $errno === '23505' ) {
 483                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 484                                 return;
 485                         }
 486                 }
 487                 /* Don't ignore serious errors */
 488                 $this->rollback( __METHOD__ );
 489                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 490         }
 491
 492         function queryIgnore( $sql, $fname = __METHOD__ ) {
 493                 return $this->query( $sql, $fname, true );
 494         }
 495
 496         function freeResult( $res ) {
 497                 if ( $res instanceof ResultWrapper ) {
 498                         $res = $res->result;
 499                 }
 500                 wfSuppressWarnings();
 501                 $ok = pg_free_result( $res );
 502                 wfRestoreWarnings();
 503                 if ( !$ok ) {
 504                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 505                 }
 506         }
 507
 508         function fetchObject( $res ) {
 509                 if ( $res instanceof ResultWrapper ) {
 510                         $res = $res->result;
 511                 }
 512                 wfSuppressWarnings();
 513                 $row = pg_fetch_object( $res );
 514                 wfRestoreWarnings();
 515                 # @todo FIXME: HACK HACK HACK HACK debug
 516
 517                 # @todo hashar: not sure if the following test really trigger if the object
 518                 #          fetching failed.
 519                 if ( pg_last_error( $this->mConn ) ) {
 520                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 521                 }
 522                 return $row;
 523         }
 524
 525         function fetchRow( $res ) {
 526                 if ( $res instanceof ResultWrapper ) {
 527                         $res = $res->result;
 528                 }
 529                 wfSuppressWarnings();
 530                 $row = pg_fetch_array( $res );
 531                 wfRestoreWarnings();
 532                 if ( pg_last_error( $this->mConn ) ) {
 533                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 534                 }
 535                 return $row;
 536         }
 537
 538         function numRows( $res ) {
 539                 if ( $res instanceof ResultWrapper ) {
 540                         $res = $res->result;
 541                 }
 542                 wfSuppressWarnings();
 543                 $n = pg_num_rows( $res );
 544                 wfRestoreWarnings();
 545                 if ( pg_last_error( $this->mConn ) ) {
 546                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 547                 }
 548                 return $n;
 549         }
 550
 551         function numFields( $res ) {
 552                 if ( $res instanceof ResultWrapper ) {
 553                         $res = $res->result;
 554                 }
 555                 return pg_num_fields( $res );
 556         }
 557
 558         function fieldName( $res, $n ) {
 559                 if ( $res instanceof ResultWrapper ) {
 560                         $res = $res->result;
 561                 }
 562                 return pg_field_name( $res, $n );
 563         }
 564
 565         /**
 566          * Return the result of the last call to nextSequenceValue();
 567          * This must be called after nextSequenceValue().
 568          *
 569          * @return integer|null
 570          */
 571         function insertId() {
 572                 return $this->mInsertId;
 573         }
 574
 575         function dataSeek( $res, $row ) {
 576                 if ( $res instanceof ResultWrapper ) {
 577                         $res = $res->result;
 578                 }
 579                 return pg_result_seek( $res, $row );
 580         }
 581
 582         function lastError() {
 583                 if ( $this->mConn ) {
 584                         if ( $this->mLastResult ) {
 585                                 return pg_result_error( $this->mLastResult );
 586                         } else {
 587                                 return pg_last_error();
 588                         }
 589                 } else {
 590                         return 'No database connection';
 591                 }
 592         }
 593         function lastErrno() {
 594                 if ( $this->mLastResult ) {
 595                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 596                 } else {
 597                         return false;
 598                 }
 599         }
 600
 601         function affectedRows() {
 602                 if ( !is_null( $this->mAffectedRows ) ) {
 603                         // Forced result for simulated queries
 604                         return $this->mAffectedRows;
 605                 }
 606                 if ( empty( $this->mLastResult ) ) {
 607                         return 0;
 608                 }
 609                 return pg_affected_rows( $this->mLastResult );
 610         }
 611
 612         /**
 613          * Estimate rows in dataset
 614          * Returns estimated count, based on EXPLAIN output
 615          * This is not necessarily an accurate estimate, so use sparingly
 616          * Returns -1 if count cannot be found
 617          * Takes same arguments as Database::select()
 618          * @return int
 619          */
 620         function estimateRowCount( $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = array() ) {
 621                 $options['EXPLAIN'] = true;
 622                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 623                 $rows = -1;
 624                 if ( $res ) {
 625                         $row = $this->fetchRow( $res );
 626                         $count = array();
 627                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 628                                 $rows = $count[1];
 629                         }
 630                 }
 631                 return $rows;
 632         }
 633
 634         /**
 635          * Returns information about an index
 636          * If errors are explicitly ignored, returns NULL on failure
 637          * @return bool|null
 638          */
 639         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 640                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 641                 $res = $this->query( $sql, $fname );
 642                 if ( !$res ) {
 643                         return null;
 644                 }
 645                 foreach ( $res as $row ) {
 646                         if ( $row->indexname == $this->indexName( $index ) ) {
 647                                 return $row;
 648                         }
 649                 }
 650                 return false;
 651         }
 652
 653         /**
 654          * Returns is of attributes used in index
 655          *
 656          * @since 1.19
 657          * @return Array
 658          */
 659         function indexAttributes( $index, $schema = false ) {
 660                 if ( $schema === false ) {
 661                         $schema = $this->getCoreSchema();
 662                 }
 663                 /*
 664                  * A subquery would be not needed if we didn't care about the order
 665                  * of attributes, but we do
 666                  */
 667                 $sql = <<<__INDEXATTR__
 668
 669                         SELECT opcname,
 670                                 attname,
 671                                 i.indoption[s.g] as option,
 672                                 pg_am.amname
 673                         FROM
 674                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 675                                         FROM
 676                                                 pg_index isub
 677                                         JOIN pg_class cis
 678                                                 ON cis.oid=isub.indexrelid
 679                                         JOIN pg_namespace ns
 680                                                 ON cis.relnamespace = ns.oid
 681                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 682                                 pg_attribute,
 683                                 pg_opclass opcls,
 684                                 pg_am,
 685                                 pg_class ci
 686                                 JOIN pg_index i
 687                                         ON ci.oid=i.indexrelid
 688                                 JOIN pg_class ct
 689                                         ON ct.oid = i.indrelid
 690                                 JOIN pg_namespace n
 691                                         ON ci.relnamespace = n.oid
 692                                 WHERE
 693                                         ci.relname='$index' AND n.nspname='$schema'
 694                                         AND     attrelid = ct.oid
 695                                         AND     i.indkey[s.g] = attnum
 696                                         AND     i.indclass[s.g] = opcls.oid
 697                                         AND     pg_am.oid = opcls.opcmethod
 698 __INDEXATTR__;
 699                 $res = $this->query( $sql, __METHOD__ );
 700                 $a = array();
 701                 if ( $res ) {
 702                         foreach ( $res as $row ) {
 703                                 $a[] = array(
 704                                         $row->attname,
 705                                         $row->opcname,
 706                                         $row->amname,
 707                                         $row->option );
 708                         }
 709                 } else {
 710                         return null;
 711                 }
 712                 return $a;
 713         }
 714
 715         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 716                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 717                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 718                         $this->strencode( $this->indexName( $index ) ) .
 719                         ")'";
 720                 $res = $this->query( $sql, $fname );
 721                 if ( !$res ) {
 722                         return null;
 723                 }
 724                 foreach ( $res as $row ) {
 725                         return true;
 726                 }
 727                 return false;
 728         }
 729
 730         /**
 731          * INSERT wrapper, inserts an array into a table
 732          *
 733          * $args may be a single associative array, or an array of these with numeric keys,
 734          * for multi-row insert (Postgres version 8.2 and above only).
 735          *
 736          * @param $table   String: Name of the table to insert to.
 737          * @param $args    Array: Items to insert into the table.
 738          * @param $fname   String: Name of the function, for profiling
 739          * @param string $options or Array. Valid options: IGNORE
 740          *
 741          * @return bool Success of insert operation. IGNORE always returns true.
 742          */
 743         function insert( $table, $args, $fname = __METHOD__, $options = array() ) {
 744                 if ( !count( $args ) ) {
 745                         return true;
 746                 }
 747
 748                 $table = $this->tableName( $table );
 749                 if ( !isset( $this->numeric_version ) ) {
 750                         $this->getServerVersion();
 751                 }
 752
 753                 if ( !is_array( $options ) ) {
 754                         $options = array( $options );
 755                 }
 756
 757                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 758                         $multi = true;
 759                         $keys = array_keys( $args[0] );
 760                 } else {
 761                         $multi = false;
 762                         $keys = array_keys( $args );
 763                 }
 764
 765                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 766                 $savepoint = null;
 767                 if ( in_array( 'IGNORE', $options ) ) {
 768                         $savepoint = new SavepointPostgres( $this, 'mw' );
 769                         $olde = error_reporting( 0 );
 770                         // For future use, we may want to track the number of actual inserts
 771                         // Right now, insert (all writes) simply return true/false
 772                         $numrowsinserted = 0;
 773                 }
 774
 775                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 776
 777                 if ( $multi ) {
 778                         if ( $this->numeric_version >= 8.2 && !$savepoint ) {
 779                                 $first = true;
 780                                 foreach ( $args as $row ) {
 781                                         if ( $first ) {
 782                                                 $first = false;
 783                                         } else {
 784                                                 $sql .= ',';
 785                                         }
 786                                         $sql .= '(' . $this->makeList( $row ) . ')';
 787                                 }
 788                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 789                         } else {
 790                                 $res = true;
 791                                 $origsql = $sql;
 792                                 foreach ( $args as $row ) {
 793                                         $tempsql = $origsql;
 794                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 795
 796                                         if ( $savepoint ) {
 797                                                 $savepoint->savepoint();
 798                                         }
 799
 800                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 801
 802                                         if ( $savepoint ) {
 803                                                 $bar = pg_last_error();
 804                                                 if ( $bar != false ) {
 805                                                         $savepoint->rollback();
 806                                                 } else {
 807                                                         $savepoint->release();
 808                                                         $numrowsinserted++;
 809                                                 }
 810                                         }
 811
 812                                         // If any of them fail, we fail overall for this function call
 813                                         // Note that this will be ignored if IGNORE is set
 814                                         if ( !$tempres ) {
 815                                                 $res = false;
 816                                         }
 817                                 }
 818                         }
 819                 } else {
 820                         // Not multi, just a lone insert
 821                         if ( $savepoint ) {
 822                                 $savepoint->savepoint();
 823                         }
 824
 825                         $sql .= '(' . $this->makeList( $args ) . ')';
 826                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 827                         if ( $savepoint ) {
 828                                 $bar = pg_last_error();
 829                                 if ( $bar != false ) {
 830                                         $savepoint->rollback();
 831                                 } else {
 832                                         $savepoint->release();
 833                                         $numrowsinserted++;
 834                                 }
 835                         }
 836                 }
 837                 if ( $savepoint ) {
 838                         $olde = error_reporting( $olde );
 839                         $savepoint->commit();
 840
 841                         // Set the affected row count for the whole operation
 842                         $this->mAffectedRows = $numrowsinserted;
 843
 844                         // IGNORE always returns true
 845                         return true;
 846                 }
 847
 848                 return $res;
 849         }
 850
 851         /**
 852          * INSERT SELECT wrapper
 853          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 854          * Source items may be literals rather then field names, but strings should be quoted with Database::addQuotes()
 855          * $conds may be "*" to copy the whole table
 856          * srcTable may be an array of tables.
 857          * @todo FIXME: Implement this a little better (seperate select/insert)?
 858          * @return bool
 859          */
 860         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 861                 $insertOptions = array(), $selectOptions = array() )
 862         {
 863                 $destTable = $this->tableName( $destTable );
 864
 865                 if ( !is_array( $insertOptions ) ) {
 866                         $insertOptions = array( $insertOptions );
 867                 }
 868
 869                 /*
 870                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
 871                  * Ignore LOW PRIORITY option, since it is MySQL-specific
 872                  */
 873                 $savepoint = null;
 874                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 875                         $savepoint = new SavepointPostgres( $this, 'mw' );
 876                         $olde = error_reporting( 0 );
 877                         $numrowsinserted = 0;
 878                         $savepoint->savepoint();
 879                 }
 880
 881                 if ( !is_array( $selectOptions ) ) {
 882                         $selectOptions = array( $selectOptions );
 883                 }
 884                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
 885                 if ( is_array( $srcTable ) ) {
 886                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
 887                 } else {
 888                         $srcTable = $this->tableName( $srcTable );
 889                 }
 890
 891                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 892                                 " SELECT $startOpts " . implode( ',', $varMap ) .
 893                                 " FROM $srcTable $useIndex";
 894
 895                 if ( $conds != '*' ) {
 896                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 897                 }
 898
 899                 $sql .= " $tailOpts";
 900
 901                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 902                 if ( $savepoint ) {
 903                         $bar = pg_last_error();
 904                         if ( $bar != false ) {
 905                                 $savepoint->rollback();
 906                         } else {
 907                                 $savepoint->release();
 908                                 $numrowsinserted++;
 909                         }
 910                         $olde = error_reporting( $olde );
 911                         $savepoint->commit();
 912
 913                         // Set the affected row count for the whole operation
 914                         $this->mAffectedRows = $numrowsinserted;
 915
 916                         // IGNORE always returns true
 917                         return true;
 918                 }
 919
 920                 return $res;
 921         }
 922
 923         function tableName( $name, $format = 'quoted' ) {
 924                 # Replace reserved words with better ones
 925                 switch ( $name ) {
 926                         case 'user':
 927                                 return $this->realTableName( 'mwuser', $format );
 928                         case 'text':
 929                                 return $this->realTableName( 'pagecontent', $format );
 930                         default:
 931                                 return $this->realTableName( $name, $format );
 932                 }
 933         }
 934
 935         /* Don't cheat on installer */
 936         function realTableName( $name, $format = 'quoted' ) {
 937                 return parent::tableName( $name, $format );
 938         }
 939
 940         /**
 941          * Return the next in a sequence, save the value for retrieval via insertId()
 942          * @return null
 943          */
 944         function nextSequenceValue( $seqName ) {
 945                 $safeseq = str_replace( "'", "''", $seqName );
 946                 $res = $this->query( "SELECT nextval('$safeseq')" );
 947                 $row = $this->fetchRow( $res );
 948                 $this->mInsertId = $row[0];
 949                 return $this->mInsertId;
 950         }
 951
 952         /**
 953          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 954          * @return
 955          */
 956         function currentSequenceValue( $seqName ) {
 957                 $safeseq = str_replace( "'", "''", $seqName );
 958                 $res = $this->query( "SELECT currval('$safeseq')" );
 959                 $row = $this->fetchRow( $res );
 960                 $currval = $row[0];
 961                 return $currval;
 962         }
 963
 964         # Returns the size of a text field, or -1 for "unlimited"
 965         function textFieldSize( $table, $field ) {
 966                 $table = $this->tableName( $table );
 967                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 968                         FROM pg_class c, pg_attribute a, pg_type t
 969                         WHERE relname='$table' AND a.attrelid=c.oid AND
 970                                 a.atttypid=t.oid and a.attname='$field'";
 971                 $res = $this->query( $sql );
 972                 $row = $this->fetchObject( $res );
 973                 if ( $row->ftype == 'varchar' ) {
 974                         $size = $row->size - 4;
 975                 } else {
 976                         $size = $row->size;
 977                 }
 978                 return $size;
 979         }
 980
 981         function limitResult( $sql, $limit, $offset = false ) {
 982                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 983         }
 984
 985         function wasDeadlock() {
 986                 return $this->lastErrno() == '40P01';
 987         }
 988
 989         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 990                 $newName = $this->addIdentifierQuotes( $newName );
 991                 $oldName = $this->addIdentifierQuotes( $oldName );
 992                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName (LIKE $oldName INCLUDING DEFAULTS)", $fname );
 993         }
 994
 995         function listTables( $prefix = null, $fname = __METHOD__ ) {
 996                 $eschema = $this->addQuotes( $this->getCoreSchema() );
 997                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
 998                 $endArray = array();
 999
1000                 foreach ( $result as $table ) {
1001                         $vars = get_object_vars( $table );
1002                         $table = array_pop( $vars );
1003                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1004                                 $endArray[] = $table;
1005                         }
1006                 }
1007
1008                 return $endArray;
1009         }
1010
1011         function timestamp( $ts = 0 ) {
1012                 return wfTimestamp( TS_POSTGRES, $ts );
1013         }
1014
1015         /*
1016          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1017          * to http://www.php.net/manual/en/ref.pgsql.php
1018          *
1019          * Parsing a postgres array can be a tricky problem, he's my
1020          * take on this, it handles multi-dimensional arrays plus
1021          * escaping using a nasty regexp to determine the limits of each
1022          * data-item.
1023          *
1024          * This should really be handled by PHP PostgreSQL module
1025          *
1026          * @since 1.19
1027          * @param $text   string: postgreql array returned in a text form like {a,b}
1028          * @param $output string
1029          * @param $limit  int
1030          * @param $offset int
1031          * @return string
1032          */
1033         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1034                 if ( false === $limit ) {
1035                         $limit = strlen( $text ) - 1;
1036                         $output = array();
1037                 }
1038                 if ( '{}' == $text ) {
1039                         return $output;
1040                 }
1041                 do {
1042                         if ( '{' != $text[$offset] ) {
1043                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1044                                         $text, $match, 0, $offset );
1045                                 $offset += strlen( $match[0] );
1046                                 $output[] = ( '"' != $match[1][0]
1047                                                 ? $match[1]
1048                                                 : stripcslashes( substr( $match[1], 1, -1 ) ) );
1049                                 if ( '},' == $match[3] ) {
1050                                         return $output;
1051                                 }
1052                         } else {
1053                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1054                         }
1055                 } while ( $limit > $offset );
1056                 return $output;
1057         }
1058
1059         /**
1060          * Return aggregated value function call
1061          */
1062         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1063                 return $valuedata;
1064         }
1065
1066         /**
1067          * @return string wikitext of a link to the server software's web site
1068          */
1069         public function getSoftwareLink() {
1070                 return '[http://www.postgresql.org/ PostgreSQL]';
1071         }
1072
1073         /**
1074          * Return current schema (executes SELECT current_schema())
1075          * Needs transaction
1076          *
1077          * @since 1.19
1078          * @return string return default schema for the current session
1079          */
1080         function getCurrentSchema() {
1081                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1082                 $row = $this->fetchRow( $res );
1083                 return $row[0];
1084         }
1085
1086         /**
1087          * Return list of schemas which are accessible without schema name
1088          * This is list does not contain magic keywords like "$user"
1089          * Needs transaction
1090          *
1091          * @see getSearchPath()
1092          * @see setSearchPath()
1093          * @since 1.19
1094          * @return array list of actual schemas for the current sesson
1095          */
1096         function getSchemas() {
1097                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1098                 $row = $this->fetchRow( $res );
1099                 $schemas = array();
1100                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1101                 return $this->pg_array_parse( $row[0], $schemas );
1102         }
1103
1104         /**
1105          * Return search patch for schemas
1106          * This is different from getSchemas() since it contain magic keywords
1107          * (like "$user").
1108          * Needs transaction
1109          *
1110          * @since 1.19
1111          * @return array how to search for table names schemas for the current user
1112          */
1113         function getSearchPath() {
1114                 $res = $this->query( "SHOW search_path", __METHOD__ );
1115                 $row = $this->fetchRow( $res );
1116                 /* PostgreSQL returns SHOW values as strings */
1117                 return explode( ",", $row[0] );
1118         }
1119
1120         /**
1121          * Update search_path, values should already be sanitized
1122          * Values may contain magic keywords like "$user"
1123          * @since 1.19
1124          *
1125          * @param $search_path array list of schemas to be searched by default
1126          */
1127         function setSearchPath( $search_path ) {
1128                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1129         }
1130
1131         /**
1132          * Determine default schema for MediaWiki core
1133          * Adjust this session schema search path if desired schema exists
1134          * and is not alread there.
1135          *
1136          * We need to have name of the core schema stored to be able
1137          * to query database metadata.
1138          *
1139          * This will be also called by the installer after the schema is created
1140          *
1141          * @since 1.19
1142          * @param $desired_schema string
1143          */
1144         function determineCoreSchema( $desired_schema ) {
1145                 $this->begin( __METHOD__ );
1146                 if ( $this->schemaExists( $desired_schema ) ) {
1147                         if ( in_array( $desired_schema, $this->getSchemas() ) ) {
1148                                 $this->mCoreSchema = $desired_schema;
1149                                 wfDebug( "Schema \"" . $desired_schema . "\" already in the search path\n" );
1150                         } else {
1151                                 /**
1152                                  * Prepend our schema (e.g. 'mediawiki') in front
1153                                  * of the search path
1154                                  * Fixes bug 15816
1155                                  */
1156                                 $search_path = $this->getSearchPath();
1157                                 array_unshift( $search_path,
1158                                         $this->addIdentifierQuotes( $desired_schema ));
1159                                 $this->setSearchPath( $search_path );
1160                                 $this->mCoreSchema = $desired_schema;
1161                                 wfDebug( "Schema \"" . $desired_schema . "\" added to the search path\n" );
1162                         }
1163                 } else {
1164                         $this->mCoreSchema = $this->getCurrentSchema();
1165                         wfDebug( "Schema \"" . $desired_schema . "\" not found, using current \"" . $this->mCoreSchema . "\"\n" );
1166                 }
1167                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1168                 $this->commit( __METHOD__ );
1169         }
1170
1171         /**
1172          * Return schema name fore core MediaWiki tables
1173          *
1174          * @since 1.19
1175          * @return string core schema name
1176          */
1177         function getCoreSchema() {
1178                 return $this->mCoreSchema;
1179         }
1180
1181         /**
1182          * @return string Version information from the database
1183          */
1184         function getServerVersion() {
1185                 if ( !isset( $this->numeric_version ) ) {
1186                         $versionInfo = pg_version( $this->mConn );
1187                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1188                                 // Old client, abort install
1189                                 $this->numeric_version = '7.3 or earlier';
1190                         } elseif ( isset( $versionInfo['server'] ) ) {
1191                                 // Normal client
1192                                 $this->numeric_version = $versionInfo['server'];
1193                         } else {
1194                                 // Bug 16937: broken pgsql extension from PHP<5.3
1195                                 $this->numeric_version = pg_parameter_status( $this->mConn, 'server_version' );
1196                         }
1197                 }
1198                 return $this->numeric_version;
1199         }
1200
1201         /**
1202          * Query whether a given relation exists (in the given schema, or the
1203          * default mw one if not given)
1204          * @return bool
1205          */
1206         function relationExists( $table, $types, $schema = false ) {
1207                 if ( !is_array( $types ) ) {
1208                         $types = array( $types );
1209                 }
1210                 if ( !$schema ) {
1211                         $schema = $this->getCoreSchema();
1212                 }
1213                 $table = $this->realTableName( $table, 'raw' );
1214                 $etable = $this->addQuotes( $table );
1215                 $eschema = $this->addQuotes( $schema );
1216                 $SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1217                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1218                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1219                 $res = $this->query( $SQL );
1220                 $count = $res ? $res->numRows() : 0;
1221                 return (bool)$count;
1222         }
1223
1224         /**
1225          * For backward compatibility, this function checks both tables and
1226          * views.
1227          * @return bool
1228          */
1229         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1230                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1231         }
1232
1233         function sequenceExists( $sequence, $schema = false ) {
1234                 return $this->relationExists( $sequence, 'S', $schema );
1235         }
1236
1237         function triggerExists( $table, $trigger ) {
1238                 $q = <<<SQL
1239         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1240                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1241                           AND tgrelid=pg_class.oid
1242                           AND nspname=%s AND relname=%s AND tgname=%s
1243 SQL;
1244                 $res = $this->query(
1245                         sprintf(
1246                                 $q,
1247                                 $this->addQuotes( $this->getCoreSchema() ),
1248                                 $this->addQuotes( $table ),
1249                                 $this->addQuotes( $trigger )
1250                         )
1251                 );
1252                 if ( !$res ) {
1253                         return null;
1254                 }
1255                 $rows = $res->numRows();
1256                 return $rows;
1257         }
1258
1259         function ruleExists( $table, $rule ) {
1260                 $exists = $this->selectField( 'pg_rules', 'rulename',
1261                         array(
1262                                 'rulename' => $rule,
1263                                 'tablename' => $table,
1264                                 'schemaname' => $this->getCoreSchema()
1265                         )
1266                 );
1267                 return $exists === $rule;
1268         }
1269
1270         function constraintExists( $table, $constraint ) {
1271                 $SQL = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1272                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1273                         $this->addQuotes( $this->getCoreSchema() ),
1274                         $this->addQuotes( $table ),
1275                         $this->addQuotes( $constraint )
1276                 );
1277                 $res = $this->query( $SQL );
1278                 if ( !$res ) {
1279                         return null;
1280                 }
1281                 $rows = $res->numRows();
1282                 return $rows;
1283         }
1284
1285         /**
1286          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1287          * @return bool
1288          */
1289         function schemaExists( $schema ) {
1290                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1291                         array( 'nspname' => $schema ), __METHOD__ );
1292                 return (bool)$exists;
1293         }
1294
1295         /**
1296          * Returns true if a given role (i.e. user) exists, false otherwise.
1297          * @return bool
1298          */
1299         function roleExists( $roleName ) {
1300                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1301                         array( 'rolname' => $roleName ), __METHOD__ );
1302                 return (bool)$exists;
1303         }
1304
1305         function fieldInfo( $table, $field ) {
1306                 return PostgresField::fromText( $this, $table, $field );
1307         }
1308
1309         /**
1310          * pg_field_type() wrapper
1311          * @return string
1312          */
1313         function fieldType( $res, $index ) {
1314                 if ( $res instanceof ResultWrapper ) {
1315                         $res = $res->result;
1316                 }
1317                 return pg_field_type( $res, $index );
1318         }
1319
1320         /**
1321          * @param $b
1322          * @return Blob
1323          */
1324         function encodeBlob( $b ) {
1325                 return new Blob( pg_escape_bytea( $this->mConn, $b ) );
1326         }
1327
1328         function decodeBlob( $b ) {
1329                 if ( $b instanceof Blob ) {
1330                         $b = $b->fetch();
1331                 }
1332                 return pg_unescape_bytea( $b );
1333         }
1334
1335         function strencode( $s ) { # Should not be called by us
1336                 return pg_escape_string( $this->mConn, $s );
1337         }
1338
1339         /**
1340          * @param $s null|bool|Blob
1341          * @return int|string
1342          */
1343         function addQuotes( $s ) {
1344                 if ( is_null( $s ) ) {
1345                         return 'NULL';
1346                 } elseif ( is_bool( $s ) ) {
1347                         return intval( $s );
1348                 } elseif ( $s instanceof Blob ) {
1349                         return "'" . $s->fetch( $s ) . "'";
1350                 }
1351                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1352         }
1353
1354         /**
1355          * Postgres specific version of replaceVars.
1356          * Calls the parent version in Database.php
1357          *
1358          * @private
1359          *
1360          * @param string $ins SQL string, read from a stream (usually tables.sql)
1361          *
1362          * @return string SQL string
1363          */
1364         protected function replaceVars( $ins ) {
1365                 $ins = parent::replaceVars( $ins );
1366
1367                 if ( $this->numeric_version >= 8.3 ) {
1368                         // Thanks for not providing backwards-compatibility, 8.3
1369                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1370                 }
1371
1372                 if ( $this->numeric_version <= 8.1 ) { // Our minimum version
1373                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1374                 }
1375
1376                 return $ins;
1377         }
1378
1379         /**
1380          * Various select options
1381          *
1382          * @private
1383          *
1384          * @param array $options an associative array of options to be turned into
1385          *              an SQL query, valid keys are listed in the function.
1386          * @return array
1387          */
1388         function makeSelectOptions( $options ) {
1389                 $preLimitTail = $postLimitTail = '';
1390                 $startOpts = $useIndex = '';
1391
1392                 $noKeyOptions = array();
1393                 foreach ( $options as $key => $option ) {
1394                         if ( is_numeric( $key ) ) {
1395                                 $noKeyOptions[$option] = true;
1396                         }
1397                 }
1398
1399                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1400
1401                 $preLimitTail .= $this->makeOrderBy( $options );
1402
1403                 //if ( isset( $options['LIMIT'] ) ) {
1404                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1405                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1406                 //              : false );
1407                 //}
1408
1409                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1410                         $postLimitTail .= ' FOR UPDATE';
1411                 }
1412                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1413                         $startOpts .= 'DISTINCT';
1414                 }
1415
1416                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1417         }
1418
1419         function setFakeMaster( $enabled = true ) {
1420         }
1421
1422         function getDBname() {
1423                 return $this->mDBname;
1424         }
1425
1426         function getServer() {
1427                 return $this->mServer;
1428         }
1429
1430         function buildConcat( $stringList ) {
1431                 return implode( ' || ', $stringList );
1432         }
1433
1434         public function buildGroupConcatField(
1435                 $delimiter, $table, $field, $conds = '', $options = array(), $join_conds = array()
1436         ) {
1437                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1438                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
1439         }
1440
1441         public function getSearchEngine() {
1442                 return 'SearchPostgres';
1443         }
1444
1445         public function streamStatementEnd( &$sql, &$newLine ) {
1446                 # Allow dollar quoting for function declarations
1447                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1448                         if ( $this->delimiter ) {
1449                                 $this->delimiter = false;
1450                         }
1451                         else {
1452                                 $this->delimiter = ';';
1453                         }
1454                 }
1455                 return parent::streamStatementEnd( $sql, $newLine );
1456         }
1457
1458         /**
1459          * Check to see if a named lock is available. This is non-blocking.
1460          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1461          *
1462          * @param string $lockName name of lock to poll
1463          * @param string $method name of method calling us
1464          * @return Boolean
1465          * @since 1.20
1466          */
1467         public function lockIsFree( $lockName, $method ) {
1468                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1469                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1470                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1471                 $row = $this->fetchObject( $result );
1472                 return ( $row->lockstatus === 't' );
1473         }
1474
1475         /**
1476          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1477          * @param $lockName string
1478          * @param $method string
1479          * @param $timeout int
1480          * @return bool
1481          */
1482         public function lock( $lockName, $method, $timeout = 5 ) {
1483                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1484                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1485                         $result = $this->query(
1486                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1487                         $row = $this->fetchObject( $result );
1488                         if ( $row->lockstatus === 't' ) {
1489                                 return true;
1490                         } else {
1491                                 sleep( 1 );
1492                         }
1493                 }
1494                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1495                 return false;
1496         }
1497
1498         /**
1499          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1500          * @param $lockName string
1501          * @param $method string
1502          * @return bool
1503          */
1504         public function unlock( $lockName, $method ) {
1505                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1506                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1507                 $row = $this->fetchObject( $result );
1508                 return ( $row->lockstatus === 't' );
1509         }
1510
1511         /**
1512          * @param string $lockName
1513          * @return string Integer
1514          */
1515         private function bigintFromLockName( $lockName ) {
1516                 return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1517         }
1518 } // end DatabasePostgres class