includes/db/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * @file
   6  * @ingroup Database
   7  */
   8
   9 class PostgresField implements Field {
  10         private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname;
  11
  12         /**
  13          * @param $db DatabaseBase
  14          * @param  $table
  15          * @param  $field
  16          * @return null|PostgresField
  17          */
  18         static function fromText( $db, $table, $field ) {
  19                 global $wgDBmwschema;
  20
  21                 $q = <<<SQL
  22 SELECT
  23  attnotnull, attlen, COALESCE(conname, '') AS conname,
  24  COALESCE(condeferred, 'f') AS deferred,
  25  COALESCE(condeferrable, 'f') AS deferrable,
  26  CASE WHEN typname = 'int2' THEN 'smallint'
  27   WHEN typname = 'int4' THEN 'integer'
  28   WHEN typname = 'int8' THEN 'bigint'
  29   WHEN typname = 'bpchar' THEN 'char'
  30  ELSE typname END AS typname
  31 FROM pg_class c
  32 JOIN pg_namespace n ON (n.oid = c.relnamespace)
  33 JOIN pg_attribute a ON (a.attrelid = c.oid)
  34 JOIN pg_type t ON (t.oid = a.atttypid)
  35 LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
  36 WHERE relkind = 'r'
  37 AND nspname=%s
  38 AND relname=%s
  39 AND attname=%s;
  40 SQL;
  41
  42                 $table = $db->tableName( $table, 'raw' );
  43                 $res = $db->query(
  44                         sprintf( $q,
  45                                 $db->addQuotes( $wgDBmwschema ),
  46                                 $db->addQuotes( $table ),
  47                                 $db->addQuotes( $field )
  48                         )
  49                 );
  50                 $row = $db->fetchObject( $res );
  51                 if ( !$row ) {
  52                         return null;
  53                 }
  54                 $n = new PostgresField;
  55                 $n->type = $row->typname;
  56                 $n->nullable = ( $row->attnotnull == 'f' );
  57                 $n->name = $field;
  58                 $n->tablename = $table;
  59                 $n->max_length = $row->attlen;
  60                 $n->deferrable = ( $row->deferrable == 't' );
  61                 $n->deferred = ( $row->deferred == 't' );
  62                 $n->conname = $row->conname;
  63                 return $n;
  64         }
  65
  66         function name() {
  67                 return $this->name;
  68         }
  69
  70         function tableName() {
  71                 return $this->tablename;
  72         }
  73
  74         function type() {
  75                 return $this->type;
  76         }
  77
  78         function isNullable() {
  79                 return $this->nullable;
  80         }
  81
  82         function maxLength() {
  83                 return $this->max_length;
  84         }
  85
  86         function is_deferrable() {
  87                 return $this->deferrable;
  88         }
  89
  90         function is_deferred() {
  91                 return $this->deferred;
  92         }
  93
  94         function conname() {
  95                 return $this->conname;
  96         }
  97
  98 }
  99
 100 /**
 101  * @ingroup Database
 102  */
 103 class DatabasePostgres extends DatabaseBase {
 104         var $mInsertId = null;
 105         var $mLastResult = null;
 106         var $numeric_version = null;
 107         var $mAffectedRows = null;
 108
 109         function getType() {
 110                 return 'postgres';
 111         }
 112
 113         function cascadingDeletes() {
 114                 return true;
 115         }
 116         function cleanupTriggers() {
 117                 return true;
 118         }
 119         function strictIPs() {
 120                 return true;
 121         }
 122         function realTimestamps() {
 123                 return true;
 124         }
 125         function implicitGroupby() {
 126                 return false;
 127         }
 128         function implicitOrderby() {
 129                 return false;
 130         }
 131         function searchableIPs() {
 132                 return true;
 133         }
 134         function functionalIndexes() {
 135                 return true;
 136         }
 137
 138         function hasConstraint( $name ) {
 139                 global $wgDBmwschema;
 140                 $SQL = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n WHERE c.connamespace = n.oid AND conname = '" .
 141                                 pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" . pg_escape_string( $this->mConn, $wgDBmwschema ) ."'";
 142                 $res = $this->doQuery( $SQL );
 143                 return $this->numRows( $res );
 144         }
 145
 146         /**
 147          * Usually aborts on failure
 148          * @return DatabaseBase|null
 149          */
 150         function open( $server, $user, $password, $dbName ) {
 151                 # Test for Postgres support, to avoid suppressed fatal error
 152                 if ( !function_exists( 'pg_connect' ) ) {
 153                         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" );
 154                 }
 155
 156                 global $wgDBport;
 157
 158                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 159                         return;
 160                 }
 161
 162                 $this->close();
 163                 $this->mServer = $server;
 164                 $port = $wgDBport;
 165                 $this->mUser = $user;
 166                 $this->mPassword = $password;
 167                 $this->mDBname = $dbName;
 168
 169                 $connectVars = array(
 170                         'dbname' => $dbName,
 171                         'user' => $user,
 172                         'password' => $password
 173                 );
 174                 if ( $server != false && $server != '' ) {
 175                         $connectVars['host'] = $server;
 176                 }
 177                 if ( $port != false && $port != '' ) {
 178                         $connectVars['port'] = $port;
 179                 }
 180                 $connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 181
 182                 $this->installErrorHandler();
 183                 $this->mConn = pg_connect( $connectString );
 184                 $phpError = $this->restoreErrorHandler();
 185
 186                 if ( !$this->mConn ) {
 187                         wfDebug( "DB connection error\n" );
 188                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 189                         wfDebug( $this->lastError() . "\n" );
 190                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 191                 }
 192
 193                 $this->mOpened = true;
 194
 195                 global $wgCommandLineMode;
 196                 # If called from the command-line (e.g. importDump), only show errors
 197                 if ( $wgCommandLineMode ) {
 198                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 199                 }
 200
 201                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 202                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 203                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 204                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 205
 206                 global $wgDBmwschema;
 207                 if ( $this->schemaExists( $wgDBmwschema ) ) {
 208                         $safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
 209                         $this->doQuery( "SET search_path = $safeschema" );
 210                 } else {
 211                         $this->doQuery( "SET search_path = public" );
 212                 }
 213
 214                 return $this->mConn;
 215         }
 216
 217         /**
 218          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 219          * DB name doesn't match the open connection, open a new one
 220          * @return
 221          */
 222         function selectDB( $db ) {
 223                 if ( $this->mDBname !== $db ) {
 224                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 225                 } else {
 226                         return true;
 227                 }
 228         }
 229
 230         function makeConnectionString( $vars ) {
 231                 $s = '';
 232                 foreach ( $vars as $name => $value ) {
 233                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 234                 }
 235                 return $s;
 236         }
 237
 238         /**
 239          * Closes a database connection, if it is open
 240          * Returns success, true if already closed
 241          * @return bool
 242          */
 243         function close() {
 244                 $this->mOpened = false;
 245                 if ( $this->mConn ) {
 246                         $ret = pg_close( $this->mConn );
 247                         $this->mConn = null;
 248                         return $ret;
 249                 } else {
 250                         return true;
 251                 }
 252         }
 253
 254         protected function doQuery( $sql ) {
 255                 if ( function_exists( 'mb_convert_encoding' ) ) {
 256                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 257                 }
 258                 $this->mLastResult = pg_query( $this->mConn, $sql );
 259                 $this->mAffectedRows = null; // use pg_affected_rows(mLastResult)
 260                 return $this->mLastResult;
 261         }
 262
 263         function queryIgnore( $sql, $fname = 'DatabasePostgres::queryIgnore' ) {
 264                 return $this->query( $sql, $fname, true );
 265         }
 266
 267         function freeResult( $res ) {
 268                 if ( $res instanceof ResultWrapper ) {
 269                         $res = $res->result;
 270                 }
 271                 wfSuppressWarnings();
 272                 $ok = pg_free_result( $res );
 273                 wfRestoreWarnings();
 274                 if ( !$ok ) {
 275                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 276                 }
 277         }
 278
 279         function fetchObject( $res ) {
 280                 if ( $res instanceof ResultWrapper ) {
 281                         $res = $res->result;
 282                 }
 283                 wfSuppressWarnings();
 284                 $row = pg_fetch_object( $res );
 285                 wfRestoreWarnings();
 286                 # @todo FIXME: HACK HACK HACK HACK debug
 287
 288                 # @todo hashar: not sure if the following test really trigger if the object
 289                 #          fetching failed.
 290                 if( pg_last_error( $this->mConn ) ) {
 291                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 292                 }
 293                 return $row;
 294         }
 295
 296         function fetchRow( $res ) {
 297                 if ( $res instanceof ResultWrapper ) {
 298                         $res = $res->result;
 299                 }
 300                 wfSuppressWarnings();
 301                 $row = pg_fetch_array( $res );
 302                 wfRestoreWarnings();
 303                 if( pg_last_error( $this->mConn ) ) {
 304                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 305                 }
 306                 return $row;
 307         }
 308
 309         function numRows( $res ) {
 310                 if ( $res instanceof ResultWrapper ) {
 311                         $res = $res->result;
 312                 }
 313                 wfSuppressWarnings();
 314                 $n = pg_num_rows( $res );
 315                 wfRestoreWarnings();
 316                 if( pg_last_error( $this->mConn ) ) {
 317                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 318                 }
 319                 return $n;
 320         }
 321
 322         function numFields( $res ) {
 323                 if ( $res instanceof ResultWrapper ) {
 324                         $res = $res->result;
 325                 }
 326                 return pg_num_fields( $res );
 327         }
 328
 329         function fieldName( $res, $n ) {
 330                 if ( $res instanceof ResultWrapper ) {
 331                         $res = $res->result;
 332                 }
 333                 return pg_field_name( $res, $n );
 334         }
 335
 336         /**
 337          * This must be called after nextSequenceVal
 338          * @return null
 339          */
 340         function insertId() {
 341                 return $this->mInsertId;
 342         }
 343
 344         function dataSeek( $res, $row ) {
 345                 if ( $res instanceof ResultWrapper ) {
 346                         $res = $res->result;
 347                 }
 348                 return pg_result_seek( $res, $row );
 349         }
 350
 351         function lastError() {
 352                 if ( $this->mConn ) {
 353                         return pg_last_error();
 354                 } else {
 355                         return 'No database connection';
 356                 }
 357         }
 358         function lastErrno() {
 359                 return pg_last_error() ? 1 : 0;
 360         }
 361
 362         function affectedRows() {
 363                 if ( !is_null( $this->mAffectedRows ) ) {
 364                         // Forced result for simulated queries
 365                         return $this->mAffectedRows;
 366                 }
 367                 if( empty( $this->mLastResult ) ) {
 368                         return 0;
 369                 }
 370                 return pg_affected_rows( $this->mLastResult );
 371         }
 372
 373         /**
 374          * Estimate rows in dataset
 375          * Returns estimated count, based on EXPLAIN output
 376          * This is not necessarily an accurate estimate, so use sparingly
 377          * Returns -1 if count cannot be found
 378          * Takes same arguments as Database::select()
 379          * @return int
 380          */
 381         function estimateRowCount( $table, $vars = '*', $conds='', $fname = 'DatabasePostgres::estimateRowCount', $options = array() ) {
 382                 $options['EXPLAIN'] = true;
 383                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 384                 $rows = -1;
 385                 if ( $res ) {
 386                         $row = $this->fetchRow( $res );
 387                         $count = array();
 388                         if( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 389                                 $rows = $count[1];
 390                         }
 391                 }
 392                 return $rows;
 393         }
 394
 395         /**
 396          * Returns information about an index
 397          * If errors are explicitly ignored, returns NULL on failure
 398          * @return bool|null
 399          */
 400         function indexInfo( $table, $index, $fname = 'DatabasePostgres::indexInfo' ) {
 401                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 402                 $res = $this->query( $sql, $fname );
 403                 if ( !$res ) {
 404                         return null;
 405                 }
 406                 foreach ( $res as $row ) {
 407                         if ( $row->indexname == $this->indexName( $index ) ) {
 408                                 return $row;
 409                         }
 410                 }
 411                 return false;
 412         }
 413
 414         function indexUnique( $table, $index, $fname = 'DatabasePostgres::indexUnique' ) {
 415                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'".
 416                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 417                         $this->strencode( $this->indexName( $index ) ) .
 418                         ")'";
 419                 $res = $this->query( $sql, $fname );
 420                 if ( !$res ) {
 421                         return null;
 422                 }
 423                 foreach ( $res as $row ) {
 424                         return true;
 425                 }
 426                 return false;
 427         }
 428
 429         /**
 430          * INSERT wrapper, inserts an array into a table
 431          *
 432          * $args may be a single associative array, or an array of these with numeric keys,
 433          * for multi-row insert (Postgres version 8.2 and above only).
 434          *
 435          * @param $table   String: Name of the table to insert to.
 436          * @param $args    Array: Items to insert into the table.
 437          * @param $fname   String: Name of the function, for profiling
 438          * @param $options String or Array. Valid options: IGNORE
 439          *
 440          * @return bool Success of insert operation. IGNORE always returns true.
 441          */
 442         function insert( $table, $args, $fname = 'DatabasePostgres::insert', $options = array() ) {
 443                 if ( !count( $args ) ) {
 444                         return true;
 445                 }
 446
 447                 $table = $this->tableName( $table );
 448                 if (! isset( $this->numeric_version ) ) {
 449                         $this->getServerVersion();
 450                 }
 451
 452                 if ( !is_array( $options ) ) {
 453                         $options = array( $options );
 454                 }
 455
 456                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 457                         $multi = true;
 458                         $keys = array_keys( $args[0] );
 459                 } else {
 460                         $multi = false;
 461                         $keys = array_keys( $args );
 462                 }
 463
 464                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 465                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 466
 467                 // If we are not in a transaction, we need to be for savepoint trickery
 468                 $didbegin = 0;
 469                 if ( $ignore ) {
 470                         if ( !$this->mTrxLevel ) {
 471                                 $this->begin( __METHOD__ );
 472                                 $didbegin = 1;
 473                         }
 474                         $olde = error_reporting( 0 );
 475                         // For future use, we may want to track the number of actual inserts
 476                         // Right now, insert (all writes) simply return true/false
 477                         $numrowsinserted = 0;
 478                 }
 479
 480                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 481
 482                 if ( $multi ) {
 483                         if ( $this->numeric_version >= 8.2 && !$ignore ) {
 484                                 $first = true;
 485                                 foreach ( $args as $row ) {
 486                                         if ( $first ) {
 487                                                 $first = false;
 488                                         } else {
 489                                                 $sql .= ',';
 490                                         }
 491                                         $sql .= '(' . $this->makeList( $row ) . ')';
 492                                 }
 493                                 $res = (bool)$this->query( $sql, $fname, $ignore );
 494                         } else {
 495                                 $res = true;
 496                                 $origsql = $sql;
 497                                 foreach ( $args as $row ) {
 498                                         $tempsql = $origsql;
 499                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 500
 501                                         if ( $ignore ) {
 502                                                 pg_query( $this->mConn, "SAVEPOINT $ignore" );
 503                                         }
 504
 505                                         $tempres = (bool)$this->query( $tempsql, $fname, $ignore );
 506
 507                                         if ( $ignore ) {
 508                                                 $bar = pg_last_error();
 509                                                 if ( $bar != false ) {
 510                                                         pg_query( $this->mConn, "ROLLBACK TO $ignore" );
 511                                                 } else {
 512                                                         pg_query( $this->mConn, "RELEASE $ignore" );
 513                                                         $numrowsinserted++;
 514                                                 }
 515                                         }
 516
 517                                         // If any of them fail, we fail overall for this function call
 518                                         // Note that this will be ignored if IGNORE is set
 519                                         if ( !$tempres ) {
 520                                                 $res = false;
 521                                         }
 522                                 }
 523                         }
 524                 } else {
 525                         // Not multi, just a lone insert
 526                         if ( $ignore ) {
 527                                 pg_query($this->mConn, "SAVEPOINT $ignore");
 528                         }
 529
 530                         $sql .= '(' . $this->makeList( $args ) . ')';
 531                         $res = (bool)$this->query( $sql, $fname, $ignore );
 532                         if ( $ignore ) {
 533                                 $bar = pg_last_error();
 534                                 if ( $bar != false ) {
 535                                         pg_query( $this->mConn, "ROLLBACK TO $ignore" );
 536                                 } else {
 537                                         pg_query( $this->mConn, "RELEASE $ignore" );
 538                                         $numrowsinserted++;
 539                                 }
 540                         }
 541                 }
 542                 if ( $ignore ) {
 543                         $olde = error_reporting( $olde );
 544                         if ( $didbegin ) {
 545                                 $this->commit( __METHOD__ );
 546                         }
 547
 548                         // Set the affected row count for the whole operation
 549                         $this->mAffectedRows = $numrowsinserted;
 550
 551                         // IGNORE always returns true
 552                         return true;
 553                 }
 554
 555                 return $res;
 556         }
 557
 558         /**
 559          * INSERT SELECT wrapper
 560          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 561          * Source items may be literals rather then field names, but strings should be quoted with Database::addQuotes()
 562          * $conds may be "*" to copy the whole table
 563          * srcTable may be an array of tables.
 564          * @todo FIXME: Implement this a little better (seperate select/insert)?
 565          * @return bool
 566          */
 567         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabasePostgres::insertSelect',
 568                 $insertOptions = array(), $selectOptions = array() )
 569         {
 570                 $destTable = $this->tableName( $destTable );
 571
 572                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 573                 $ignore = in_array( 'IGNORE', $insertOptions ) ? 'mw' : '';
 574
 575                 if( is_array( $insertOptions ) ) {
 576                         $insertOptions = implode( ' ', $insertOptions ); // FIXME: This is unused
 577                 }
 578                 if( !is_array( $selectOptions ) ) {
 579                         $selectOptions = array( $selectOptions );
 580                 }
 581                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
 582                 if( is_array( $srcTable ) ) {
 583                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
 584                 } else {
 585                         $srcTable = $this->tableName( $srcTable );
 586                 }
 587
 588                 // If we are not in a transaction, we need to be for savepoint trickery
 589                 $didbegin = 0;
 590                 if ( $ignore ) {
 591                         if( !$this->mTrxLevel ) {
 592                                 $this->begin( __METHOD__ );
 593                                 $didbegin = 1;
 594                         }
 595                         $olde = error_reporting( 0 );
 596                         $numrowsinserted = 0;
 597                         pg_query( $this->mConn, "SAVEPOINT $ignore");
 598                 }
 599
 600                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 601                                 " SELECT $startOpts " . implode( ',', $varMap ) .
 602                                 " FROM $srcTable $useIndex";
 603
 604                 if ( $conds != '*' ) {
 605                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 606                 }
 607
 608                 $sql .= " $tailOpts";
 609
 610                 $res = (bool)$this->query( $sql, $fname, $ignore );
 611                 if( $ignore ) {
 612                         $bar = pg_last_error();
 613                         if( $bar != false ) {
 614                                 pg_query( $this->mConn, "ROLLBACK TO $ignore" );
 615                         } else {
 616                                 pg_query( $this->mConn, "RELEASE $ignore" );
 617                                 $numrowsinserted++;
 618                         }
 619                         $olde = error_reporting( $olde );
 620                         if( $didbegin ) {
 621                                 $this->commit( __METHOD__ );
 622                         }
 623
 624                         // Set the affected row count for the whole operation
 625                         $this->mAffectedRows = $numrowsinserted;
 626
 627                         // IGNORE always returns true
 628                         return true;
 629                 }
 630
 631                 return $res;
 632         }
 633
 634         function tableName( $name, $format = 'quoted' ) {
 635                 # Replace reserved words with better ones
 636                 switch( $name ) {
 637                         case 'user':
 638                                 return 'mwuser';
 639                         case 'text':
 640                                 return 'pagecontent';
 641                         default:
 642                                 return parent::tableName( $name, $format );
 643                 }
 644         }
 645
 646         /**
 647          * Return the next in a sequence, save the value for retrieval via insertId()
 648          * @return null
 649          */
 650         function nextSequenceValue( $seqName ) {
 651                 $safeseq = str_replace( "'", "''", $seqName );
 652                 $res = $this->query( "SELECT nextval('$safeseq')" );
 653                 $row = $this->fetchRow( $res );
 654                 $this->mInsertId = $row[0];
 655                 return $this->mInsertId;
 656         }
 657
 658         /**
 659          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 660          * @return
 661          */
 662         function currentSequenceValue( $seqName ) {
 663                 $safeseq = str_replace( "'", "''", $seqName );
 664                 $res = $this->query( "SELECT currval('$safeseq')" );
 665                 $row = $this->fetchRow( $res );
 666                 $currval = $row[0];
 667                 return $currval;
 668         }
 669
 670         # Returns the size of a text field, or -1 for "unlimited"
 671         function textFieldSize( $table, $field ) {
 672                 $table = $this->tableName( $table );
 673                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 674                         FROM pg_class c, pg_attribute a, pg_type t
 675                         WHERE relname='$table' AND a.attrelid=c.oid AND
 676                                 a.atttypid=t.oid and a.attname='$field'";
 677                 $res =$this->query( $sql );
 678                 $row = $this->fetchObject( $res );
 679                 if ( $row->ftype == 'varchar' ) {
 680                         $size = $row->size - 4;
 681                 } else {
 682                         $size = $row->size;
 683                 }
 684                 return $size;
 685         }
 686
 687         function limitResult( $sql, $limit, $offset = false ) {
 688                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 689         }
 690
 691         function wasDeadlock() {
 692                 return $this->lastErrno() == '40P01';
 693         }
 694
 695         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabasePostgres::duplicateTableStructure' ) {
 696                 $newName = $this->addIdentifierQuotes( $newName );
 697                 $oldName = $this->addIdentifierQuotes( $oldName );
 698                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName (LIKE $oldName INCLUDING DEFAULTS)", $fname );
 699         }
 700
 701         function listTables( $prefix = null, $fname = 'DatabasePostgres::listTables' ) {
 702                 global $wgDBmwschema;
 703                 $eschema = $this->addQuotes( $wgDBmwschema );
 704                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
 705
 706                 $endArray = array();
 707
 708                 foreach( $result as $table ) {
 709                         $vars = get_object_vars($table);
 710                         $table = array_pop( $vars );
 711                         if( !$prefix || strpos( $table, $prefix ) === 0 ) {
 712                                 $endArray[] = $table;
 713                         }
 714                 }
 715
 716                 return $endArray;
 717         }
 718
 719         function timestamp( $ts = 0 ) {
 720                 return wfTimestamp( TS_POSTGRES, $ts );
 721         }
 722
 723         /**
 724          * Return aggregated value function call
 725          */
 726         function aggregateValue( $valuedata, $valuename = 'value' ) {
 727                 return $valuedata;
 728         }
 729
 730         /**
 731          * @return string wikitext of a link to the server software's web site
 732          */
 733         public static function getSoftwareLink() {
 734                 return '[http://www.postgresql.org/ PostgreSQL]';
 735         }
 736
 737         /**
 738          * @return string Version information from the database
 739          */
 740         function getServerVersion() {
 741                 if ( !isset( $this->numeric_version ) ) {
 742                         $versionInfo = pg_version( $this->mConn );
 743                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
 744                                 // Old client, abort install
 745                                 $this->numeric_version = '7.3 or earlier';
 746                         } elseif ( isset( $versionInfo['server'] ) ) {
 747                                 // Normal client
 748                                 $this->numeric_version = $versionInfo['server'];
 749                         } else {
 750                                 // Bug 16937: broken pgsql extension from PHP<5.3
 751                                 $this->numeric_version = pg_parameter_status( $this->mConn, 'server_version' );
 752                         }
 753                 }
 754                 return $this->numeric_version;
 755         }
 756
 757         /**
 758          * Query whether a given relation exists (in the given schema, or the
 759          * default mw one if not given)
 760          * @return bool
 761          */
 762         function relationExists( $table, $types, $schema = false ) {
 763                 global $wgDBmwschema;
 764                 if ( !is_array( $types ) ) {
 765                         $types = array( $types );
 766                 }
 767                 if ( !$schema ) {
 768                         $schema = $wgDBmwschema;
 769                 }
 770                 $table = $this->tableName( $table, 'raw' );
 771                 $etable = $this->addQuotes( $table );
 772                 $eschema = $this->addQuotes( $schema );
 773                 $SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
 774                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
 775                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
 776                 $res = $this->query( $SQL );
 777                 $count = $res ? $res->numRows() : 0;
 778                 return (bool)$count;
 779         }
 780
 781         /**
 782          * For backward compatibility, this function checks both tables and
 783          * views.
 784          * @return bool
 785          */
 786         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
 787                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
 788         }
 789
 790         function sequenceExists( $sequence, $schema = false ) {
 791                 return $this->relationExists( $sequence, 'S', $schema );
 792         }
 793
 794         function triggerExists( $table, $trigger ) {
 795                 global $wgDBmwschema;
 796
 797                 $q = <<<SQL
 798         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
 799                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
 800                           AND tgrelid=pg_class.oid
 801                           AND nspname=%s AND relname=%s AND tgname=%s
 802 SQL;
 803                 $res = $this->query(
 804                         sprintf(
 805                                 $q,
 806                                 $this->addQuotes( $wgDBmwschema ),
 807                                 $this->addQuotes( $table ),
 808                                 $this->addQuotes( $trigger )
 809                         )
 810                 );
 811                 if ( !$res ) {
 812                         return null;
 813                 }
 814                 $rows = $res->numRows();
 815                 return $rows;
 816         }
 817
 818         function ruleExists( $table, $rule ) {
 819                 global $wgDBmwschema;
 820                 $exists = $this->selectField( 'pg_rules', 'rulename',
 821                         array(
 822                                 'rulename' => $rule,
 823                                 'tablename' => $table,
 824                                 'schemaname' => $wgDBmwschema
 825                         )
 826                 );
 827                 return $exists === $rule;
 828         }
 829
 830         function constraintExists( $table, $constraint ) {
 831                 global $wgDBmwschema;
 832                 $SQL = sprintf( "SELECT 1 FROM information_schema.table_constraints ".
 833                            "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
 834                         $this->addQuotes( $wgDBmwschema ),
 835                         $this->addQuotes( $table ),
 836                         $this->addQuotes( $constraint )
 837                 );
 838                 $res = $this->query( $SQL );
 839                 if ( !$res ) {
 840                         return null;
 841                 }
 842                 $rows = $res->numRows();
 843                 return $rows;
 844         }
 845
 846         /**
 847          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
 848          * @return bool
 849          */
 850         function schemaExists( $schema ) {
 851                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
 852                         array( 'nspname' => $schema ), __METHOD__ );
 853                 return (bool)$exists;
 854         }
 855
 856         /**
 857          * Returns true if a given role (i.e. user) exists, false otherwise.
 858          * @return bool
 859          */
 860         function roleExists( $roleName ) {
 861                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
 862                         array( 'rolname' => $roleName ), __METHOD__ );
 863                 return (bool)$exists;
 864         }
 865
 866         function fieldInfo( $table, $field ) {
 867                 return PostgresField::fromText( $this, $table, $field );
 868         }
 869
 870         /**
 871          * pg_field_type() wrapper
 872          * @return string
 873          */
 874         function fieldType( $res, $index ) {
 875                 if ( $res instanceof ResultWrapper ) {
 876                         $res = $res->result;
 877                 }
 878                 return pg_field_type( $res, $index );
 879         }
 880
 881         /* Not even sure why this is used in the main codebase... */
 882         function limitResultForUpdate( $sql, $num ) {
 883                 return $sql;
 884         }
 885
 886         /**
 887          * @param $b
 888          * @return Blob
 889          */
 890         function encodeBlob( $b ) {
 891                 return new Blob( pg_escape_bytea( $this->mConn, $b ) );
 892         }
 893
 894         function decodeBlob( $b ) {
 895                 if ( $b instanceof Blob ) {
 896                         $b = $b->fetch();
 897                 }
 898                 return pg_unescape_bytea( $b );
 899         }
 900
 901         function strencode( $s ) { # Should not be called by us
 902                 return pg_escape_string( $this->mConn, $s );
 903         }
 904
 905         /**
 906          * @param $s null|bool|Blob
 907          * @return int|string
 908          */
 909         function addQuotes( $s ) {
 910                 if ( is_null( $s ) ) {
 911                         return 'NULL';
 912                 } elseif ( is_bool( $s ) ) {
 913                         return intval( $s );
 914                 } elseif ( $s instanceof Blob ) {
 915                         return "'" . $s->fetch( $s ) . "'";
 916                 }
 917                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
 918         }
 919
 920         /**
 921          * Postgres specific version of replaceVars.
 922          * Calls the parent version in Database.php
 923          *
 924          * @private
 925          *
 926          * @param $ins String: SQL string, read from a stream (usually tables.sql)
 927          *
 928          * @return string SQL string
 929          */
 930         protected function replaceVars( $ins ) {
 931                 $ins = parent::replaceVars( $ins );
 932
 933                 if ( $this->numeric_version >= 8.3 ) {
 934                         // Thanks for not providing backwards-compatibility, 8.3
 935                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
 936                 }
 937
 938                 if ( $this->numeric_version <= 8.1 ) { // Our minimum version
 939                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
 940                 }
 941
 942                 return $ins;
 943         }
 944
 945         /**
 946          * Various select options
 947          *
 948          * @private
 949          *
 950          * @param $options Array: an associative array of options to be turned into
 951          *              an SQL query, valid keys are listed in the function.
 952          * @return array
 953          */
 954         function makeSelectOptions( $options ) {
 955                 $preLimitTail = $postLimitTail = '';
 956                 $startOpts = $useIndex = '';
 957
 958                 $noKeyOptions = array();
 959                 foreach ( $options as $key => $option ) {
 960                         if ( is_numeric( $key ) ) {
 961                                 $noKeyOptions[$option] = true;
 962                         }
 963                 }
 964
 965                 if ( isset( $options['GROUP BY'] ) ) {
 966                         $gb = is_array( $options['GROUP BY'] )
 967                                 ? implode( ',', $options['GROUP BY'] )
 968                                 : $options['GROUP BY'];
 969                         $preLimitTail .= " GROUP BY {$gb}";
 970                 }
 971
 972                 if ( isset( $options['HAVING'] ) ) {
 973                         $preLimitTail .= " HAVING {$options['HAVING']}";
 974                 }
 975
 976                 if ( isset( $options['ORDER BY'] ) ) {
 977                         $ob = is_array( $options['ORDER BY'] )
 978                                 ? implode( ',', $options['ORDER BY'] )
 979                                 : $options['ORDER BY'];
 980                         $preLimitTail .= " ORDER BY {$ob}";
 981                 }
 982
 983                 //if ( isset( $options['LIMIT'] ) ) {
 984                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
 985                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
 986                 //              : false );
 987                 //}
 988
 989                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
 990                         $postLimitTail .= ' FOR UPDATE';
 991                 }
 992                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
 993                         $postLimitTail .= ' LOCK IN SHARE MODE';
 994                 }
 995                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
 996                         $startOpts .= 'DISTINCT';
 997                 }
 998
 999                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1000         }
1001
1002         function setFakeMaster( $enabled = true ) {}
1003
1004         function getDBname() {
1005                 return $this->mDBname;
1006         }
1007
1008         function getServer() {
1009                 return $this->mServer;
1010         }
1011
1012         function buildConcat( $stringList ) {
1013                 return implode( ' || ', $stringList );
1014         }
1015
1016         public function getSearchEngine() {
1017                 return 'SearchPostgres';
1018         }
1019
1020         public function streamStatementEnd( &$sql, &$newLine ) {
1021                 # Allow dollar quoting for function declarations
1022                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1023                         if ( $this->delimiter ) {
1024                                 $this->delimiter = false;
1025                         }
1026                         else {
1027                                 $this->delimiter = ';';
1028                         }
1029                 }
1030                 return parent::streamStatementEnd( $sql, $newLine );
1031         }
1032 } // end DatabasePostgres class