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                 $this->mConn = pg_connect( $this->connectString );
 374                 $phpError = $this->restoreErrorHandler();
 375
 376                 if ( !$this->mConn ) {
 377                         wfDebug( "DB connection error\n" );
 378                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 379                         wfDebug( $this->lastError() . "\n" );
 380                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 381                 }
 382
 383                 $this->mOpened = true;
 384                 $this->mTransactionState = new PostgresTransactionState( $this->mConn );
 385
 386                 global $wgCommandLineMode;
 387                 # If called from the command-line (e.g. importDump), only show errors
 388                 if ( $wgCommandLineMode ) {
 389                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 390                 }
 391
 392                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 393                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 394                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 395                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 396                 if ( $this->getServerVersion() >= 9.0 ) {
 397                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 398                 }
 399
 400                 global $wgDBmwschema;
 401                 $this->determineCoreSchema( $wgDBmwschema );
 402
 403                 return $this->mConn;
 404         }
 405
 406         /**
 407          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 408          * DB name doesn't match the open connection, open a new one
 409          * @return
 410          */
 411         function selectDB( $db ) {
 412                 if ( $this->mDBname !== $db ) {
 413                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 414                 } else {
 415                         return true;
 416                 }
 417         }
 418
 419         function makeConnectionString( $vars ) {
 420                 $s = '';
 421                 foreach ( $vars as $name => $value ) {
 422                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 423                 }
 424                 return $s;
 425         }
 426
 427         /**
 428          * Closes a database connection, if it is open
 429          * Returns success, true if already closed
 430          * @return bool
 431          */
 432         protected function closeConnection() {
 433                 return pg_close( $this->mConn );
 434         }
 435
 436         public function doQuery( $sql ) {
 437                 if ( function_exists( 'mb_convert_encoding' ) ) {
 438                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 439                 }
 440                 $this->mTransactionState->check();
 441                 if( pg_send_query( $this->mConn, $sql ) === false ) {
 442                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 443                 }
 444                 $this->mLastResult = pg_get_result( $this->mConn );
 445                 $this->mTransactionState->check();
 446                 $this->mAffectedRows = null;
 447                 if ( pg_result_error( $this->mLastResult ) ) {
 448                         return false;
 449                 }
 450                 return $this->mLastResult;
 451         }
 452
 453         protected function dumpError() {
 454                 $diags = array( PGSQL_DIAG_SEVERITY,
 455                                 PGSQL_DIAG_SQLSTATE,
 456                                 PGSQL_DIAG_MESSAGE_PRIMARY,
 457                                 PGSQL_DIAG_MESSAGE_DETAIL,
 458                                 PGSQL_DIAG_MESSAGE_HINT,
 459                                 PGSQL_DIAG_STATEMENT_POSITION,
 460                                 PGSQL_DIAG_INTERNAL_POSITION,
 461                                 PGSQL_DIAG_INTERNAL_QUERY,
 462                                 PGSQL_DIAG_CONTEXT,
 463                                 PGSQL_DIAG_SOURCE_FILE,
 464                                 PGSQL_DIAG_SOURCE_LINE,
 465                                 PGSQL_DIAG_SOURCE_FUNCTION );
 466                 foreach ( $diags as $d ) {
 467                         wfDebug( sprintf("PgSQL ERROR(%d): %s\n", $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 468                 }
 469         }
 470
 471         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 472                 /* Transaction stays in the ERROR state until rolledback */
 473                 if ( $tempIgnore ) {
 474                         /* Check for constraint violation */
 475                         if ( $errno === '23505' ) {
 476                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 477                                 return;
 478                         }
 479                 }
 480                 /* Don't ignore serious errors */
 481                 $this->rollback( __METHOD__ );
 482                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 483         }
 484
 485         function queryIgnore( $sql, $fname = 'DatabasePostgres::queryIgnore' ) {
 486                 return $this->query( $sql, $fname, true );
 487         }
 488
 489         function freeResult( $res ) {
 490                 if ( $res instanceof ResultWrapper ) {
 491                         $res = $res->result;
 492                 }
 493                 wfSuppressWarnings();
 494                 $ok = pg_free_result( $res );
 495                 wfRestoreWarnings();
 496                 if ( !$ok ) {
 497                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 498                 }
 499         }
 500
 501         function fetchObject( $res ) {
 502                 if ( $res instanceof ResultWrapper ) {
 503                         $res = $res->result;
 504                 }
 505                 wfSuppressWarnings();
 506                 $row = pg_fetch_object( $res );
 507                 wfRestoreWarnings();
 508                 # @todo FIXME: HACK HACK HACK HACK debug
 509
 510                 # @todo hashar: not sure if the following test really trigger if the object
 511                 #          fetching failed.
 512                 if( pg_last_error( $this->mConn ) ) {
 513                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 514                 }
 515                 return $row;
 516         }
 517
 518         function fetchRow( $res ) {
 519                 if ( $res instanceof ResultWrapper ) {
 520                         $res = $res->result;
 521                 }
 522                 wfSuppressWarnings();
 523                 $row = pg_fetch_array( $res );
 524                 wfRestoreWarnings();
 525                 if( pg_last_error( $this->mConn ) ) {
 526                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 527                 }
 528                 return $row;
 529         }
 530
 531         function numRows( $res ) {
 532                 if ( $res instanceof ResultWrapper ) {
 533                         $res = $res->result;
 534                 }
 535                 wfSuppressWarnings();
 536                 $n = pg_num_rows( $res );
 537                 wfRestoreWarnings();
 538                 if( pg_last_error( $this->mConn ) ) {
 539                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 540                 }
 541                 return $n;
 542         }
 543
 544         function numFields( $res ) {
 545                 if ( $res instanceof ResultWrapper ) {
 546                         $res = $res->result;
 547                 }
 548                 return pg_num_fields( $res );
 549         }
 550
 551         function fieldName( $res, $n ) {
 552                 if ( $res instanceof ResultWrapper ) {
 553                         $res = $res->result;
 554                 }
 555                 return pg_field_name( $res, $n );
 556         }
 557
 558         /**
 559          * Return the result of the last call to nextSequenceValue();
 560          * This must be called after nextSequenceValue().
 561          *
 562          * @return integer|null
 563          */
 564         function insertId() {
 565                 return $this->mInsertId;
 566         }
 567
 568         function dataSeek( $res, $row ) {
 569                 if ( $res instanceof ResultWrapper ) {
 570                         $res = $res->result;
 571                 }
 572                 return pg_result_seek( $res, $row );
 573         }
 574
 575         function lastError() {
 576                 if ( $this->mConn ) {
 577                         if ( $this->mLastResult ) {
 578                                 return pg_result_error( $this->mLastResult );
 579                         } else {
 580                                 return pg_last_error();
 581                         }
 582                 } else {
 583                         return 'No database connection';
 584                 }
 585         }
 586         function lastErrno() {
 587                 if ( $this->mLastResult ) {
 588                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 589                 } else {
 590                         return false;
 591                 }
 592         }
 593
 594         function affectedRows() {
 595                 if ( !is_null( $this->mAffectedRows ) ) {
 596                         // Forced result for simulated queries
 597                         return $this->mAffectedRows;
 598                 }
 599                 if( empty( $this->mLastResult ) ) {
 600                         return 0;
 601                 }
 602                 return pg_affected_rows( $this->mLastResult );
 603         }
 604
 605         /**
 606          * Estimate rows in dataset
 607          * Returns estimated count, based on EXPLAIN output
 608          * This is not necessarily an accurate estimate, so use sparingly
 609          * Returns -1 if count cannot be found
 610          * Takes same arguments as Database::select()
 611          * @return int
 612          */
 613         function estimateRowCount( $table, $vars = '*', $conds = '', $fname = 'DatabasePostgres::estimateRowCount', $options = array() ) {
 614                 $options['EXPLAIN'] = true;
 615                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 616                 $rows = -1;
 617                 if ( $res ) {
 618                         $row = $this->fetchRow( $res );
 619                         $count = array();
 620                         if( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 621                                 $rows = $count[1];
 622                         }
 623                 }
 624                 return $rows;
 625         }
 626
 627         /**
 628          * Returns information about an index
 629          * If errors are explicitly ignored, returns NULL on failure
 630          * @return bool|null
 631          */
 632         function indexInfo( $table, $index, $fname = 'DatabasePostgres::indexInfo' ) {
 633                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 634                 $res = $this->query( $sql, $fname );
 635                 if ( !$res ) {
 636                         return null;
 637                 }
 638                 foreach ( $res as $row ) {
 639                         if ( $row->indexname == $this->indexName( $index ) ) {
 640                                 return $row;
 641                         }
 642                 }
 643                 return false;
 644         }
 645
 646         /**
 647          * Returns is of attributes used in index
 648          *
 649          * @since 1.19
 650          * @return Array
 651          */
 652         function indexAttributes( $index, $schema = false ) {
 653                 if ( $schema === false )
 654                         $schema = $this->getCoreSchema();
 655                 /*
 656                  * A subquery would be not needed if we didn't care about the order
 657                  * of attributes, but we do
 658                  */
 659                 $sql = <<<__INDEXATTR__
 660
 661                         SELECT opcname,
 662                                 attname,
 663                                 i.indoption[s.g] as option,
 664                                 pg_am.amname
 665                         FROM
 666                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 667                                         FROM
 668                                                 pg_index isub
 669                                         JOIN pg_class cis
 670                                                 ON cis.oid=isub.indexrelid
 671                                         JOIN pg_namespace ns
 672                                                 ON cis.relnamespace = ns.oid
 673                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 674                                 pg_attribute,
 675                                 pg_opclass opcls,
 676                                 pg_am,
 677                                 pg_class ci
 678                                 JOIN pg_index i
 679                                         ON ci.oid=i.indexrelid
 680                                 JOIN pg_class ct
 681                                         ON ct.oid = i.indrelid
 682                                 JOIN pg_namespace n
 683                                         ON ci.relnamespace = n.oid
 684                                 WHERE
 685                                         ci.relname='$index' AND n.nspname='$schema'
 686                                         AND     attrelid = ct.oid
 687                                         AND     i.indkey[s.g] = attnum
 688                                         AND     i.indclass[s.g] = opcls.oid
 689                                         AND     pg_am.oid = opcls.opcmethod
 690 __INDEXATTR__;
 691                 $res = $this->query( $sql, __METHOD__ );
 692                 $a = array();
 693                 if ( $res ) {
 694                         foreach ( $res as $row ) {
 695                                 $a[] = array(
 696                                         $row->attname,
 697                                         $row->opcname,
 698                                         $row->amname,
 699                                         $row->option );
 700                         }
 701                 } else {
 702                         return null;
 703                 }
 704                 return $a;
 705         }
 706
 707         function indexUnique( $table, $index, $fname = 'DatabasePostgres::indexUnique' ) {
 708                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 709                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 710                         $this->strencode( $this->indexName( $index ) ) .
 711                         ")'";
 712                 $res = $this->query( $sql, $fname );
 713                 if ( !$res ) {
 714                         return null;
 715                 }
 716                 foreach ( $res as $row ) {
 717                         return true;
 718                 }
 719                 return false;
 720         }
 721
 722         /**
 723          * INSERT wrapper, inserts an array into a table
 724          *
 725          * $args may be a single associative array, or an array of these with numeric keys,
 726          * for multi-row insert (Postgres version 8.2 and above only).
 727          *
 728          * @param $table   String: Name of the table to insert to.
 729          * @param $args    Array: Items to insert into the table.
 730          * @param $fname   String: Name of the function, for profiling
 731          * @param string $options or Array. Valid options: IGNORE
 732          *
 733          * @return bool Success of insert operation. IGNORE always returns true.
 734          */
 735         function insert( $table, $args, $fname = 'DatabasePostgres::insert', $options = array() ) {
 736                 if ( !count( $args ) ) {
 737                         return true;
 738                 }
 739
 740                 $table = $this->tableName( $table );
 741                 if ( !isset( $this->numeric_version ) ) {
 742                         $this->getServerVersion();
 743                 }
 744
 745                 if ( !is_array( $options ) ) {
 746                         $options = array( $options );
 747                 }
 748
 749                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 750                         $multi = true;
 751                         $keys = array_keys( $args[0] );
 752                 } else {
 753                         $multi = false;
 754                         $keys = array_keys( $args );
 755                 }
 756
 757                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 758                 $savepoint = null;
 759                 if ( in_array( 'IGNORE', $options ) ) {
 760                         $savepoint = new SavepointPostgres( $this, 'mw' );
 761                         $olde = error_reporting( 0 );
 762                         // For future use, we may want to track the number of actual inserts
 763                         // Right now, insert (all writes) simply return true/false
 764                         $numrowsinserted = 0;
 765                 }
 766
 767                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 768
 769                 if ( $multi ) {
 770                         if ( $this->numeric_version >= 8.2 && !$savepoint ) {
 771                                 $first = true;
 772                                 foreach ( $args as $row ) {
 773                                         if ( $first ) {
 774                                                 $first = false;
 775                                         } else {
 776                                                 $sql .= ',';
 777                                         }
 778                                         $sql .= '(' . $this->makeList( $row ) . ')';
 779                                 }
 780                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 781                         } else {
 782                                 $res = true;
 783                                 $origsql = $sql;
 784                                 foreach ( $args as $row ) {
 785                                         $tempsql = $origsql;
 786                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 787
 788                                         if ( $savepoint ) {
 789                                                 $savepoint->savepoint();
 790                                         }
 791
 792                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 793
 794                                         if ( $savepoint ) {
 795                                                 $bar = pg_last_error();
 796                                                 if ( $bar != false ) {
 797                                                         $savepoint->rollback();
 798                                                 } else {
 799                                                         $savepoint->release();
 800                                                         $numrowsinserted++;
 801                                                 }
 802                                         }
 803
 804                                         // If any of them fail, we fail overall for this function call
 805                                         // Note that this will be ignored if IGNORE is set
 806                                         if ( !$tempres ) {
 807                                                 $res = false;
 808                                         }
 809                                 }
 810                         }
 811                 } else {
 812                         // Not multi, just a lone insert
 813                         if ( $savepoint ) {
 814                                 $savepoint->savepoint();
 815                         }
 816
 817                         $sql .= '(' . $this->makeList( $args ) . ')';
 818                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 819                         if ( $savepoint ) {
 820                                 $bar = pg_last_error();
 821                                 if ( $bar != false ) {
 822                                         $savepoint->rollback();
 823                                 } else {
 824                                         $savepoint->release();
 825                                         $numrowsinserted++;
 826                                 }
 827                         }
 828                 }
 829                 if ( $savepoint ) {
 830                         $olde = error_reporting( $olde );
 831                         $savepoint->commit();
 832
 833                         // Set the affected row count for the whole operation
 834                         $this->mAffectedRows = $numrowsinserted;
 835
 836                         // IGNORE always returns true
 837                         return true;
 838                 }
 839
 840                 return $res;
 841         }
 842
 843         /**
 844          * INSERT SELECT wrapper
 845          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 846          * Source items may be literals rather then field names, but strings should be quoted with Database::addQuotes()
 847          * $conds may be "*" to copy the whole table
 848          * srcTable may be an array of tables.
 849          * @todo FIXME: Implement this a little better (seperate select/insert)?
 850          * @return bool
 851          */
 852         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabasePostgres::insertSelect',
 853                 $insertOptions = array(), $selectOptions = array() )
 854         {
 855                 $destTable = $this->tableName( $destTable );
 856
 857                 if( !is_array( $insertOptions ) ) {
 858                         $insertOptions = array( $insertOptions );
 859                 }
 860
 861                 /*
 862                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
 863                  * Ignore LOW PRIORITY option, since it is MySQL-specific
 864                  */
 865                 $savepoint = null;
 866                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 867                         $savepoint = new SavepointPostgres( $this, 'mw' );
 868                         $olde = error_reporting( 0 );
 869                         $numrowsinserted = 0;
 870                         $savepoint->savepoint();
 871                 }
 872
 873                 if( !is_array( $selectOptions ) ) {
 874                         $selectOptions = array( $selectOptions );
 875                 }
 876                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
 877                 if( is_array( $srcTable ) ) {
 878                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
 879                 } else {
 880                         $srcTable = $this->tableName( $srcTable );
 881                 }
 882
 883                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 884                                 " SELECT $startOpts " . implode( ',', $varMap ) .
 885                                 " FROM $srcTable $useIndex";
 886
 887                 if ( $conds != '*' ) {
 888                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 889                 }
 890
 891                 $sql .= " $tailOpts";
 892
 893                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 894                 if( $savepoint ) {
 895                         $bar = pg_last_error();
 896                         if( $bar != false ) {
 897                                 $savepoint->rollback();
 898                         } else {
 899                                 $savepoint->release();
 900                                 $numrowsinserted++;
 901                         }
 902                         $olde = error_reporting( $olde );
 903                         $savepoint->commit();
 904
 905                         // Set the affected row count for the whole operation
 906                         $this->mAffectedRows = $numrowsinserted;
 907
 908                         // IGNORE always returns true
 909                         return true;
 910                 }
 911
 912                 return $res;
 913         }
 914
 915         function tableName( $name, $format = 'quoted' ) {
 916                 # Replace reserved words with better ones
 917                 switch( $name ) {
 918                         case 'user':
 919                                 return $this->realTableName( 'mwuser', $format );
 920                         case 'text':
 921                                 return $this->realTableName( 'pagecontent', $format );
 922                         default:
 923                                 return $this->realTableName( $name, $format );
 924                 }
 925         }
 926
 927         /* Don't cheat on installer */
 928         function realTableName( $name, $format = 'quoted' ) {
 929                 return parent::tableName( $name, $format );
 930         }
 931
 932         /**
 933          * Return the next in a sequence, save the value for retrieval via insertId()
 934          * @return null
 935          */
 936         function nextSequenceValue( $seqName ) {
 937                 $safeseq = str_replace( "'", "''", $seqName );
 938                 $res = $this->query( "SELECT nextval('$safeseq')" );
 939                 $row = $this->fetchRow( $res );
 940                 $this->mInsertId = $row[0];
 941                 return $this->mInsertId;
 942         }
 943
 944         /**
 945          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 946          * @return
 947          */
 948         function currentSequenceValue( $seqName ) {
 949                 $safeseq = str_replace( "'", "''", $seqName );
 950                 $res = $this->query( "SELECT currval('$safeseq')" );
 951                 $row = $this->fetchRow( $res );
 952                 $currval = $row[0];
 953                 return $currval;
 954         }
 955
 956         # Returns the size of a text field, or -1 for "unlimited"
 957         function textFieldSize( $table, $field ) {
 958                 $table = $this->tableName( $table );
 959                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
 960                         FROM pg_class c, pg_attribute a, pg_type t
 961                         WHERE relname='$table' AND a.attrelid=c.oid AND
 962                                 a.atttypid=t.oid and a.attname='$field'";
 963                 $res = $this->query( $sql );
 964                 $row = $this->fetchObject( $res );
 965                 if ( $row->ftype == 'varchar' ) {
 966                         $size = $row->size - 4;
 967                 } else {
 968                         $size = $row->size;
 969                 }
 970                 return $size;
 971         }
 972
 973         function limitResult( $sql, $limit, $offset = false ) {
 974                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
 975         }
 976
 977         function wasDeadlock() {
 978                 return $this->lastErrno() == '40P01';
 979         }
 980
 981         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabasePostgres::duplicateTableStructure' ) {
 982                 $newName = $this->addIdentifierQuotes( $newName );
 983                 $oldName = $this->addIdentifierQuotes( $oldName );
 984                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName (LIKE $oldName INCLUDING DEFAULTS)", $fname );
 985         }
 986
 987         function listTables( $prefix = null, $fname = 'DatabasePostgres::listTables' ) {
 988                 $eschema = $this->addQuotes( $this->getCoreSchema() );
 989                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
 990                 $endArray = array();
 991
 992                 foreach( $result as $table ) {
 993                         $vars = get_object_vars( $table );
 994                         $table = array_pop( $vars );
 995                         if( !$prefix || strpos( $table, $prefix ) === 0 ) {
 996                                 $endArray[] = $table;
 997                         }
 998                 }
 999
1000                 return $endArray;
1001         }
1002
1003         function timestamp( $ts = 0 ) {
1004                 return wfTimestamp( TS_POSTGRES, $ts );
1005         }
1006
1007         /*
1008          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1009          * to http://www.php.net/manual/en/ref.pgsql.php
1010          *
1011          * Parsing a postgres array can be a tricky problem, he's my
1012          * take on this, it handles multi-dimensional arrays plus
1013          * escaping using a nasty regexp to determine the limits of each
1014          * data-item.
1015          *
1016          * This should really be handled by PHP PostgreSQL module
1017          *
1018          * @since 1.19
1019          * @param $text   string: postgreql array returned in a text form like {a,b}
1020          * @param $output string
1021          * @param $limit  int
1022          * @param $offset int
1023          * @return string
1024          */
1025         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1026                 if( false === $limit ) {
1027                         $limit = strlen( $text ) - 1;
1028                         $output = array();
1029                 }
1030                 if( '{}' == $text ) {
1031                         return $output;
1032                 }
1033                 do {
1034                         if ( '{' != $text{$offset} ) {
1035                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1036                                         $text, $match, 0, $offset );
1037                                 $offset += strlen( $match[0] );
1038                                 $output[] = ( '"' != $match[1]{0}
1039                                                 ? $match[1]
1040                                                 : stripcslashes( substr( $match[1], 1, -1 ) ) );
1041                                 if ( '},' == $match[3] ) {
1042                                         return $output;
1043                                 }
1044                         } else {
1045                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1046                         }
1047                 } while ( $limit > $offset );
1048                 return $output;
1049         }
1050
1051         /**
1052          * Return aggregated value function call
1053          */
1054         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1055                 return $valuedata;
1056         }
1057
1058         /**
1059          * @return string wikitext of a link to the server software's web site
1060          */
1061         public static function getSoftwareLink() {
1062                 return '[http://www.postgresql.org/ PostgreSQL]';
1063         }
1064
1065         /**
1066          * Return current schema (executes SELECT current_schema())
1067          * Needs transaction
1068          *
1069          * @since 1.19
1070          * @return string return default schema for the current session
1071          */
1072         function getCurrentSchema() {
1073                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1074                 $row = $this->fetchRow( $res );
1075                 return $row[0];
1076         }
1077
1078         /**
1079          * Return list of schemas which are accessible without schema name
1080          * This is list does not contain magic keywords like "$user"
1081          * Needs transaction
1082          *
1083          * @see getSearchPath()
1084          * @see setSearchPath()
1085          * @since 1.19
1086          * @return array list of actual schemas for the current sesson
1087          */
1088         function getSchemas() {
1089                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1090                 $row = $this->fetchRow( $res );
1091                 $schemas = array();
1092                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1093                 return $this->pg_array_parse( $row[0], $schemas );
1094         }
1095
1096         /**
1097          * Return search patch for schemas
1098          * This is different from getSchemas() since it contain magic keywords
1099          * (like "$user").
1100          * Needs transaction
1101          *
1102          * @since 1.19
1103          * @return array how to search for table names schemas for the current user
1104          */
1105         function getSearchPath() {
1106                 $res = $this->query( "SHOW search_path", __METHOD__ );
1107                 $row = $this->fetchRow( $res );
1108                 /* PostgreSQL returns SHOW values as strings */
1109                 return explode( ",", $row[0] );
1110         }
1111
1112         /**
1113          * Update search_path, values should already be sanitized
1114          * Values may contain magic keywords like "$user"
1115          * @since 1.19
1116          *
1117          * @param $search_path array list of schemas to be searched by default
1118          */
1119         function setSearchPath( $search_path ) {
1120                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1121         }
1122
1123         /**
1124          * Determine default schema for MediaWiki core
1125          * Adjust this session schema search path if desired schema exists
1126          * and is not alread there.
1127          *
1128          * We need to have name of the core schema stored to be able
1129          * to query database metadata.
1130          *
1131          * This will be also called by the installer after the schema is created
1132          *
1133          * @since 1.19
1134          * @param $desired_schema string
1135          */
1136         function determineCoreSchema( $desired_schema ) {
1137                 $this->begin( __METHOD__ );
1138                 if ( $this->schemaExists( $desired_schema ) ) {
1139                         if ( in_array( $desired_schema, $this->getSchemas() ) ) {
1140                                 $this->mCoreSchema = $desired_schema;
1141                                 wfDebug( "Schema \"" . $desired_schema . "\" already in the search path\n" );
1142                         } else {
1143                                 /**
1144                                  * Prepend our schema (e.g. 'mediawiki') in front
1145                                  * of the search path
1146                                  * Fixes bug 15816
1147                                  */
1148                                 $search_path = $this->getSearchPath();
1149                                 array_unshift( $search_path,
1150                                         $this->addIdentifierQuotes( $desired_schema ));
1151                                 $this->setSearchPath( $search_path );
1152                                 $this->mCoreSchema = $desired_schema;
1153                                 wfDebug( "Schema \"" . $desired_schema . "\" added to the search path\n" );
1154                         }
1155                 } else {
1156                         $this->mCoreSchema = $this->getCurrentSchema();
1157                         wfDebug( "Schema \"" . $desired_schema . "\" not found, using current \"" . $this->mCoreSchema . "\"\n" );
1158                 }
1159                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1160                 $this->commit( __METHOD__ );
1161         }
1162
1163         /**
1164          * Return schema name fore core MediaWiki tables
1165          *
1166          * @since 1.19
1167          * @return string core schema name
1168          */
1169         function getCoreSchema() {
1170                 return $this->mCoreSchema;
1171         }
1172
1173         /**
1174          * @return string Version information from the database
1175          */
1176         function getServerVersion() {
1177                 if ( !isset( $this->numeric_version ) ) {
1178                         $versionInfo = pg_version( $this->mConn );
1179                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1180                                 // Old client, abort install
1181                                 $this->numeric_version = '7.3 or earlier';
1182                         } elseif ( isset( $versionInfo['server'] ) ) {
1183                                 // Normal client
1184                                 $this->numeric_version = $versionInfo['server'];
1185                         } else {
1186                                 // Bug 16937: broken pgsql extension from PHP<5.3
1187                                 $this->numeric_version = pg_parameter_status( $this->mConn, 'server_version' );
1188                         }
1189                 }
1190                 return $this->numeric_version;
1191         }
1192
1193         /**
1194          * Query whether a given relation exists (in the given schema, or the
1195          * default mw one if not given)
1196          * @return bool
1197          */
1198         function relationExists( $table, $types, $schema = false ) {
1199                 if ( !is_array( $types ) ) {
1200                         $types = array( $types );
1201                 }
1202                 if ( !$schema ) {
1203                         $schema = $this->getCoreSchema();
1204                 }
1205                 $table = $this->realTableName( $table, 'raw' );
1206                 $etable = $this->addQuotes( $table );
1207                 $eschema = $this->addQuotes( $schema );
1208                 $SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1209                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1210                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1211                 $res = $this->query( $SQL );
1212                 $count = $res ? $res->numRows() : 0;
1213                 return (bool)$count;
1214         }
1215
1216         /**
1217          * For backward compatibility, this function checks both tables and
1218          * views.
1219          * @return bool
1220          */
1221         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1222                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1223         }
1224
1225         function sequenceExists( $sequence, $schema = false ) {
1226                 return $this->relationExists( $sequence, 'S', $schema );
1227         }
1228
1229         function triggerExists( $table, $trigger ) {
1230                 $q = <<<SQL
1231         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1232                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1233                           AND tgrelid=pg_class.oid
1234                           AND nspname=%s AND relname=%s AND tgname=%s
1235 SQL;
1236                 $res = $this->query(
1237                         sprintf(
1238                                 $q,
1239                                 $this->addQuotes( $this->getCoreSchema() ),
1240                                 $this->addQuotes( $table ),
1241                                 $this->addQuotes( $trigger )
1242                         )
1243                 );
1244                 if ( !$res ) {
1245                         return null;
1246                 }
1247                 $rows = $res->numRows();
1248                 return $rows;
1249         }
1250
1251         function ruleExists( $table, $rule ) {
1252                 $exists = $this->selectField( 'pg_rules', 'rulename',
1253                         array(
1254                                 'rulename' => $rule,
1255                                 'tablename' => $table,
1256                                 'schemaname' => $this->getCoreSchema()
1257                         )
1258                 );
1259                 return $exists === $rule;
1260         }
1261
1262         function constraintExists( $table, $constraint ) {
1263                 $SQL = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1264                                 "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1265                         $this->addQuotes( $this->getCoreSchema() ),
1266                         $this->addQuotes( $table ),
1267                         $this->addQuotes( $constraint )
1268                 );
1269                 $res = $this->query( $SQL );
1270                 if ( !$res ) {
1271                         return null;
1272                 }
1273                 $rows = $res->numRows();
1274                 return $rows;
1275         }
1276
1277         /**
1278          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1279          * @return bool
1280          */
1281         function schemaExists( $schema ) {
1282                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1283                         array( 'nspname' => $schema ), __METHOD__ );
1284                 return (bool)$exists;
1285         }
1286
1287         /**
1288          * Returns true if a given role (i.e. user) exists, false otherwise.
1289          * @return bool
1290          */
1291         function roleExists( $roleName ) {
1292                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1293                         array( 'rolname' => $roleName ), __METHOD__ );
1294                 return (bool)$exists;
1295         }
1296
1297         function fieldInfo( $table, $field ) {
1298                 return PostgresField::fromText( $this, $table, $field );
1299         }
1300
1301         /**
1302          * pg_field_type() wrapper
1303          * @return string
1304          */
1305         function fieldType( $res, $index ) {
1306                 if ( $res instanceof ResultWrapper ) {
1307                         $res = $res->result;
1308                 }
1309                 return pg_field_type( $res, $index );
1310         }
1311
1312         /**
1313          * @param $b
1314          * @return Blob
1315          */
1316         function encodeBlob( $b ) {
1317                 return new Blob( pg_escape_bytea( $this->mConn, $b ) );
1318         }
1319
1320         function decodeBlob( $b ) {
1321                 if ( $b instanceof Blob ) {
1322                         $b = $b->fetch();
1323                 }
1324                 return pg_unescape_bytea( $b );
1325         }
1326
1327         function strencode( $s ) { # Should not be called by us
1328                 return pg_escape_string( $this->mConn, $s );
1329         }
1330
1331         /**
1332          * @param $s null|bool|Blob
1333          * @return int|string
1334          */
1335         function addQuotes( $s ) {
1336                 if ( is_null( $s ) ) {
1337                         return 'NULL';
1338                 } elseif ( is_bool( $s ) ) {
1339                         return intval( $s );
1340                 } elseif ( $s instanceof Blob ) {
1341                         return "'" . $s->fetch( $s ) . "'";
1342                 }
1343                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1344         }
1345
1346         /**
1347          * Postgres specific version of replaceVars.
1348          * Calls the parent version in Database.php
1349          *
1350          * @private
1351          *
1352          * @param string $ins SQL string, read from a stream (usually tables.sql)
1353          *
1354          * @return string SQL string
1355          */
1356         protected function replaceVars( $ins ) {
1357                 $ins = parent::replaceVars( $ins );
1358
1359                 if ( $this->numeric_version >= 8.3 ) {
1360                         // Thanks for not providing backwards-compatibility, 8.3
1361                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1362                 }
1363
1364                 if ( $this->numeric_version <= 8.1 ) { // Our minimum version
1365                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1366                 }
1367
1368                 return $ins;
1369         }
1370
1371         /**
1372          * Various select options
1373          *
1374          * @private
1375          *
1376          * @param array $options an associative array of options to be turned into
1377          *              an SQL query, valid keys are listed in the function.
1378          * @return array
1379          */
1380         function makeSelectOptions( $options ) {
1381                 $preLimitTail = $postLimitTail = '';
1382                 $startOpts = $useIndex = '';
1383
1384                 $noKeyOptions = array();
1385                 foreach ( $options as $key => $option ) {
1386                         if ( is_numeric( $key ) ) {
1387                                 $noKeyOptions[$option] = true;
1388                         }
1389                 }
1390
1391                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1392
1393                 $preLimitTail .= $this->makeOrderBy( $options );
1394
1395                 //if ( isset( $options['LIMIT'] ) ) {
1396                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1397                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1398                 //              : false );
1399                 //}
1400
1401                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1402                         $postLimitTail .= ' FOR UPDATE';
1403                 }
1404                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1405                         $startOpts .= 'DISTINCT';
1406                 }
1407
1408                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1409         }
1410
1411         function setFakeMaster( $enabled = true ) {
1412         }
1413
1414         function getDBname() {
1415                 return $this->mDBname;
1416         }
1417
1418         function getServer() {
1419                 return $this->mServer;
1420         }
1421
1422         function buildConcat( $stringList ) {
1423                 return implode( ' || ', $stringList );
1424         }
1425
1426         public function getSearchEngine() {
1427                 return 'SearchPostgres';
1428         }
1429
1430         public function streamStatementEnd( &$sql, &$newLine ) {
1431                 # Allow dollar quoting for function declarations
1432                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1433                         if ( $this->delimiter ) {
1434                                 $this->delimiter = false;
1435                         }
1436                         else {
1437                                 $this->delimiter = ';';
1438                         }
1439                 }
1440                 return parent::streamStatementEnd( $sql, $newLine );
1441         }
1442
1443         /**
1444          * Check to see if a named lock is available. This is non-blocking.
1445          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1446          *
1447          * @param string $lockName name of lock to poll
1448          * @param string $method name of method calling us
1449          * @return Boolean
1450          * @since 1.20
1451          */
1452         public function lockIsFree( $lockName, $method ) {
1453                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1454                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1455                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1456                 $row = $this->fetchObject( $result );
1457                 return ( $row->lockstatus === 't' );
1458         }
1459
1460         /**
1461          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1462          * @param $lockName string
1463          * @param $method string
1464          * @param $timeout int
1465          * @return bool
1466          */
1467         public function lock( $lockName, $method, $timeout = 5 ) {
1468                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1469                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1470                         $result = $this->query(
1471                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1472                         $row = $this->fetchObject( $result );
1473                         if ( $row->lockstatus === 't' ) {
1474                                 return true;
1475                         } else {
1476                                 sleep( 1 );
1477                         }
1478                 }
1479                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1480                 return false;
1481         }
1482
1483         /**
1484          * 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
1485          * @param $lockName string
1486          * @param $method string
1487          * @return bool
1488          */
1489         public function unlock( $lockName, $method ) {
1490                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1491                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1492                 $row = $this->fetchObject( $result );
1493                 return ( $row->lockstatus === 't' );
1494         }
1495
1496         /**
1497          * @param string $lockName
1498          * @return string Integer
1499          */
1500         private function bigintFromLockName( $lockName ) {
1501                 return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1502         }
1503 } // end DatabasePostgres class