includes/db/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 class PostgresField implements Field {
  25         private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname,
  26                 $has_default, $default;
  27
  28         /**
  29          * @param DatabaseBase $db
  30          * @param string $table
  31          * @param string $field
  32          * @return null|PostgresField
  33          */
  34         static function fromText( $db, $table, $field ) {
  35                 $q = <<<SQL
  36 SELECT
  37  attnotnull, attlen, conname AS conname,
  38  atthasdef,
  39  adsrc,
  40  COALESCE(condeferred, 'f') AS deferred,
  41  COALESCE(condeferrable, 'f') AS deferrable,
  42  CASE WHEN typname = 'int2' THEN 'smallint'
  43   WHEN typname = 'int4' THEN 'integer'
  44   WHEN typname = 'int8' THEN 'bigint'
  45   WHEN typname = 'bpchar' THEN 'char'
  46  ELSE typname END AS typname
  47 FROM pg_class c
  48 JOIN pg_namespace n ON (n.oid = c.relnamespace)
  49 JOIN pg_attribute a ON (a.attrelid = c.oid)
  50 JOIN pg_type t ON (t.oid = a.atttypid)
  51 LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
  52 LEFT JOIN pg_attrdef d on c.oid=d.adrelid and a.attnum=d.adnum
  53 WHERE relkind = 'r'
  54 AND nspname=%s
  55 AND relname=%s
  56 AND attname=%s;
  57 SQL;
  58
  59                 $table = $db->tableName( $table, 'raw' );
  60                 $res = $db->query(
  61                         sprintf( $q,
  62                                 $db->addQuotes( $db->getCoreSchema() ),
  63                                 $db->addQuotes( $table ),
  64                                 $db->addQuotes( $field )
  65                         )
  66                 );
  67                 $row = $db->fetchObject( $res );
  68                 if ( !$row ) {
  69                         return null;
  70                 }
  71                 $n = new PostgresField;
  72                 $n->type = $row->typname;
  73                 $n->nullable = ( $row->attnotnull == 'f' );
  74                 $n->name = $field;
  75                 $n->tablename = $table;
  76                 $n->max_length = $row->attlen;
  77                 $n->deferrable = ( $row->deferrable == 't' );
  78                 $n->deferred = ( $row->deferred == 't' );
  79                 $n->conname = $row->conname;
  80                 $n->has_default = ( $row->atthasdef === 't' );
  81                 $n->default = $row->adsrc;
  82
  83                 return $n;
  84         }
  85
  86         function name() {
  87                 return $this->name;
  88         }
  89
  90         function tableName() {
  91                 return $this->tablename;
  92         }
  93
  94         function type() {
  95                 return $this->type;
  96         }
  97
  98         function isNullable() {
  99                 return $this->nullable;
 100         }
 101
 102         function maxLength() {
 103                 return $this->max_length;
 104         }
 105
 106         function is_deferrable() {
 107                 return $this->deferrable;
 108         }
 109
 110         function is_deferred() {
 111                 return $this->deferred;
 112         }
 113
 114         function conname() {
 115                 return $this->conname;
 116         }
 117
 118         /**
 119          * @since 1.19
 120          * @return bool|mixed
 121          */
 122         function defaultValue() {
 123                 if ( $this->has_default ) {
 124                         return $this->default;
 125                 } else {
 126                         return false;
 127                 }
 128         }
 129 }
 130
 131 /**
 132  * Manage savepoints within a transaction
 133  * @ingroup Database
 134  * @since 1.19
 135  */
 136 class SavepointPostgres {
 137         /** @var DatabasePostgres Establish a savepoint within a transaction */
 138         protected $dbw;
 139         protected $id;
 140         protected $didbegin;
 141
 142         /**
 143          * @param DatabaseBase $dbw
 144          * @param int $id
 145          */
 146         public function __construct( $dbw, $id ) {
 147                 $this->dbw = $dbw;
 148                 $this->id = $id;
 149                 $this->didbegin = false;
 150                 /* If we are not in a transaction, we need to be for savepoint trickery */
 151                 if ( !$dbw->trxLevel() ) {
 152                         $dbw->begin( "FOR SAVEPOINT" );
 153                         $this->didbegin = true;
 154                 }
 155         }
 156
 157         public function __destruct() {
 158                 if ( $this->didbegin ) {
 159                         $this->dbw->rollback();
 160                         $this->didbegin = false;
 161                 }
 162         }
 163
 164         public function commit() {
 165                 if ( $this->didbegin ) {
 166                         $this->dbw->commit();
 167                         $this->didbegin = false;
 168                 }
 169         }
 170
 171         protected function query( $keyword, $msg_ok, $msg_failed ) {
 172                 if ( $this->dbw->doQuery( $keyword . " " . $this->id ) !== false ) {
 173                 } else {
 174                         wfDebug( sprintf( $msg_failed, $this->id ) );
 175                 }
 176         }
 177
 178         public function savepoint() {
 179                 $this->query( "SAVEPOINT",
 180                         "Transaction state: savepoint \"%s\" established.\n",
 181                         "Transaction state: establishment of savepoint \"%s\" FAILED.\n"
 182                 );
 183         }
 184
 185         public function release() {
 186                 $this->query( "RELEASE",
 187                         "Transaction state: savepoint \"%s\" released.\n",
 188                         "Transaction state: release of savepoint \"%s\" FAILED.\n"
 189                 );
 190         }
 191
 192         public function rollback() {
 193                 $this->query( "ROLLBACK TO",
 194                         "Transaction state: savepoint \"%s\" rolled back.\n",
 195                         "Transaction state: rollback of savepoint \"%s\" FAILED.\n"
 196                 );
 197         }
 198
 199         public function __toString() {
 200                 return (string)$this->id;
 201         }
 202 }
 203
 204 /**
 205  * @ingroup Database
 206  */
 207 class DatabasePostgres extends Database {
 208         /** @var resource */
 209         protected $mLastResult = null;
 210
 211         /** @var int The number of rows affected as an integer */
 212         protected $mAffectedRows = null;
 213
 214         /** @var int */
 215         private $mInsertId = null;
 216
 217         /** @var float|string */
 218         private $numericVersion = null;
 219
 220         /** @var string Connect string to open a PostgreSQL connection */
 221         private $connectString;
 222
 223         /** @var string */
 224         private $mCoreSchema;
 225
 226         function getType() {
 227                 return 'postgres';
 228         }
 229
 230         function cascadingDeletes() {
 231                 return true;
 232         }
 233
 234         function cleanupTriggers() {
 235                 return true;
 236         }
 237
 238         function strictIPs() {
 239                 return true;
 240         }
 241
 242         function realTimestamps() {
 243                 return true;
 244         }
 245
 246         function implicitGroupby() {
 247                 return false;
 248         }
 249
 250         function implicitOrderby() {
 251                 return false;
 252         }
 253
 254         function searchableIPs() {
 255                 return true;
 256         }
 257
 258         function functionalIndexes() {
 259                 return true;
 260         }
 261
 262         function hasConstraint( $name ) {
 263                 $sql = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n " .
 264                         "WHERE c.connamespace = n.oid AND conname = '" .
 265                         pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" .
 266                         pg_escape_string( $this->mConn, $this->getCoreSchema() ) . "'";
 267                 $res = $this->doQuery( $sql );
 268
 269                 return $this->numRows( $res );
 270         }
 271
 272         /**
 273          * Usually aborts on failure
 274          * @param string $server
 275          * @param string $user
 276          * @param string $password
 277          * @param string $dbName
 278          * @throws DBConnectionError|Exception
 279          * @return DatabaseBase|null
 280          */
 281         function open( $server, $user, $password, $dbName ) {
 282                 # Test for Postgres support, to avoid suppressed fatal error
 283                 if ( !function_exists( 'pg_connect' ) ) {
 284                         throw new DBConnectionError(
 285                                 $this,
 286                                 "Postgres functions missing, have you compiled PHP with the --with-pgsql\n" .
 287                                 "option? (Note: if you recently installed PHP, you may need to restart your\n" .
 288                                 "webserver and database)\n"
 289                         );
 290                 }
 291
 292                 global $wgDBport;
 293
 294                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 295                         return null;
 296                 }
 297
 298                 $this->mServer = $server;
 299                 $port = $wgDBport;
 300                 $this->mUser = $user;
 301                 $this->mPassword = $password;
 302                 $this->mDBname = $dbName;
 303
 304                 $connectVars = array(
 305                         'dbname' => $dbName,
 306                         'user' => $user,
 307                         'password' => $password
 308                 );
 309                 if ( $server != false && $server != '' ) {
 310                         $connectVars['host'] = $server;
 311                 }
 312                 if ( $port != false && $port != '' ) {
 313                         $connectVars['port'] = $port;
 314                 }
 315                 if ( $this->mFlags & DBO_SSL ) {
 316                         $connectVars['sslmode'] = 1;
 317                 }
 318
 319                 $this->connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 320                 $this->close();
 321                 $this->installErrorHandler();
 322
 323                 try {
 324                         $this->mConn = pg_connect( $this->connectString );
 325                 } catch ( Exception $ex ) {
 326                         $this->restoreErrorHandler();
 327                         throw $ex;
 328                 }
 329
 330                 $phpError = $this->restoreErrorHandler();
 331
 332                 if ( !$this->mConn ) {
 333                         wfDebug( "DB connection error\n" );
 334                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " .
 335                                 substr( $password, 0, 3 ) . "...\n" );
 336                         wfDebug( $this->lastError() . "\n" );
 337                         throw new DBConnectionError( $this, str_replace( "\n", ' ', $phpError ) );
 338                 }
 339
 340                 $this->mOpened = true;
 341
 342                 global $wgCommandLineMode;
 343                 # If called from the command-line (e.g. importDump), only show errors
 344                 if ( $wgCommandLineMode ) {
 345                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 346                 }
 347
 348                 $this->query( "SET client_encoding='UTF8'", __METHOD__ );
 349                 $this->query( "SET datestyle = 'ISO, YMD'", __METHOD__ );
 350                 $this->query( "SET timezone = 'GMT'", __METHOD__ );
 351                 $this->query( "SET standard_conforming_strings = on", __METHOD__ );
 352                 if ( $this->getServerVersion() >= 9.0 ) {
 353                         $this->query( "SET bytea_output = 'escape'", __METHOD__ ); // PHP bug 53127
 354                 }
 355
 356                 global $wgDBmwschema;
 357                 $this->determineCoreSchema( $wgDBmwschema );
 358
 359                 return $this->mConn;
 360         }
 361
 362         /**
 363          * Postgres doesn't support selectDB in the same way MySQL does. So if the
 364          * DB name doesn't match the open connection, open a new one
 365          * @param string $db
 366          * @return bool
 367          */
 368         function selectDB( $db ) {
 369                 if ( $this->mDBname !== $db ) {
 370                         return (bool)$this->open( $this->mServer, $this->mUser, $this->mPassword, $db );
 371                 } else {
 372                         return true;
 373                 }
 374         }
 375
 376         function makeConnectionString( $vars ) {
 377                 $s = '';
 378                 foreach ( $vars as $name => $value ) {
 379                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 380                 }
 381
 382                 return $s;
 383         }
 384
 385         /**
 386          * Closes a database connection, if it is open
 387          * Returns success, true if already closed
 388          * @return bool
 389          */
 390         protected function closeConnection() {
 391                 return pg_close( $this->mConn );
 392         }
 393
 394         public function doQuery( $sql ) {
 395                 if ( function_exists( 'mb_convert_encoding' ) ) {
 396                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 397                 }
 398                 if ( pg_send_query( $this->mConn, $sql ) === false ) {
 399                         throw new DBUnexpectedError( $this, "Unable to post new query to PostgreSQL\n" );
 400                 }
 401                 $this->mLastResult = pg_get_result( $this->mConn );
 402                 $this->mAffectedRows = null;
 403                 if ( pg_result_error( $this->mLastResult ) ) {
 404                         return false;
 405                 }
 406
 407                 return $this->mLastResult;
 408         }
 409
 410         protected function dumpError() {
 411                 $diags = array(
 412                         PGSQL_DIAG_SEVERITY,
 413                         PGSQL_DIAG_SQLSTATE,
 414                         PGSQL_DIAG_MESSAGE_PRIMARY,
 415                         PGSQL_DIAG_MESSAGE_DETAIL,
 416                         PGSQL_DIAG_MESSAGE_HINT,
 417                         PGSQL_DIAG_STATEMENT_POSITION,
 418                         PGSQL_DIAG_INTERNAL_POSITION,
 419                         PGSQL_DIAG_INTERNAL_QUERY,
 420                         PGSQL_DIAG_CONTEXT,
 421                         PGSQL_DIAG_SOURCE_FILE,
 422                         PGSQL_DIAG_SOURCE_LINE,
 423                         PGSQL_DIAG_SOURCE_FUNCTION
 424                 );
 425                 foreach ( $diags as $d ) {
 426                         wfDebug( sprintf( "PgSQL ERROR(%d): %s\n",
 427                                 $d, pg_result_error_field( $this->mLastResult, $d ) ) );
 428                 }
 429         }
 430
 431         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
 432                 if ( $tempIgnore ) {
 433                         /* Check for constraint violation */
 434                         if ( $errno === '23505' ) {
 435                                 parent::reportQueryError( $error, $errno, $sql, $fname, $tempIgnore );
 436
 437                                 return;
 438                         }
 439                 }
 440                 /* Transaction stays in the ERROR state until rolled back */
 441                 if ( $this->mTrxLevel ) {
 442                         $ignore = $this->ignoreErrors( true );
 443                         $this->rollback( __METHOD__ );
 444                         $this->ignoreErrors( $ignore );
 445                 }
 446                 parent::reportQueryError( $error, $errno, $sql, $fname, false );
 447         }
 448
 449         function queryIgnore( $sql, $fname = __METHOD__ ) {
 450                 return $this->query( $sql, $fname, true );
 451         }
 452
 453         /**
 454          * @param stdClass|ResultWrapper $res
 455          * @throws DBUnexpectedError
 456          */
 457         function freeResult( $res ) {
 458                 if ( $res instanceof ResultWrapper ) {
 459                         $res = $res->result;
 460                 }
 461                 MediaWiki\suppressWarnings();
 462                 $ok = pg_free_result( $res );
 463                 MediaWiki\restoreWarnings();
 464                 if ( !$ok ) {
 465                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 466                 }
 467         }
 468
 469         /**
 470          * @param ResultWrapper|stdClass $res
 471          * @return stdClass
 472          * @throws DBUnexpectedError
 473          */
 474         function fetchObject( $res ) {
 475                 if ( $res instanceof ResultWrapper ) {
 476                         $res = $res->result;
 477                 }
 478                 MediaWiki\suppressWarnings();
 479                 $row = pg_fetch_object( $res );
 480                 MediaWiki\restoreWarnings();
 481                 # @todo FIXME: HACK HACK HACK HACK debug
 482
 483                 # @todo hashar: not sure if the following test really trigger if the object
 484                 #          fetching failed.
 485                 if ( pg_last_error( $this->mConn ) ) {
 486                         throw new DBUnexpectedError(
 487                                 $this,
 488                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 489                         );
 490                 }
 491
 492                 return $row;
 493         }
 494
 495         function fetchRow( $res ) {
 496                 if ( $res instanceof ResultWrapper ) {
 497                         $res = $res->result;
 498                 }
 499                 MediaWiki\suppressWarnings();
 500                 $row = pg_fetch_array( $res );
 501                 MediaWiki\restoreWarnings();
 502                 if ( pg_last_error( $this->mConn ) ) {
 503                         throw new DBUnexpectedError(
 504                                 $this,
 505                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 506                         );
 507                 }
 508
 509                 return $row;
 510         }
 511
 512         function numRows( $res ) {
 513                 if ( $res instanceof ResultWrapper ) {
 514                         $res = $res->result;
 515                 }
 516                 MediaWiki\suppressWarnings();
 517                 $n = pg_num_rows( $res );
 518                 MediaWiki\restoreWarnings();
 519                 if ( pg_last_error( $this->mConn ) ) {
 520                         throw new DBUnexpectedError(
 521                                 $this,
 522                                 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) )
 523                         );
 524                 }
 525
 526                 return $n;
 527         }
 528
 529         function numFields( $res ) {
 530                 if ( $res instanceof ResultWrapper ) {
 531                         $res = $res->result;
 532                 }
 533
 534                 return pg_num_fields( $res );
 535         }
 536
 537         function fieldName( $res, $n ) {
 538                 if ( $res instanceof ResultWrapper ) {
 539                         $res = $res->result;
 540                 }
 541
 542                 return pg_field_name( $res, $n );
 543         }
 544
 545         /**
 546          * Return the result of the last call to nextSequenceValue();
 547          * This must be called after nextSequenceValue().
 548          *
 549          * @return int|null
 550          */
 551         function insertId() {
 552                 return $this->mInsertId;
 553         }
 554
 555         /**
 556          * @param mixed $res
 557          * @param int $row
 558          * @return bool
 559          */
 560         function dataSeek( $res, $row ) {
 561                 if ( $res instanceof ResultWrapper ) {
 562                         $res = $res->result;
 563                 }
 564
 565                 return pg_result_seek( $res, $row );
 566         }
 567
 568         function lastError() {
 569                 if ( $this->mConn ) {
 570                         if ( $this->mLastResult ) {
 571                                 return pg_result_error( $this->mLastResult );
 572                         } else {
 573                                 return pg_last_error();
 574                         }
 575                 } else {
 576                         return 'No database connection';
 577                 }
 578         }
 579
 580         function lastErrno() {
 581                 if ( $this->mLastResult ) {
 582                         return pg_result_error_field( $this->mLastResult, PGSQL_DIAG_SQLSTATE );
 583                 } else {
 584                         return false;
 585                 }
 586         }
 587
 588         function affectedRows() {
 589                 if ( !is_null( $this->mAffectedRows ) ) {
 590                         // Forced result for simulated queries
 591                         return $this->mAffectedRows;
 592                 }
 593                 if ( empty( $this->mLastResult ) ) {
 594                         return 0;
 595                 }
 596
 597                 return pg_affected_rows( $this->mLastResult );
 598         }
 599
 600         /**
 601          * Estimate rows in dataset
 602          * Returns estimated count, based on EXPLAIN output
 603          * This is not necessarily an accurate estimate, so use sparingly
 604          * Returns -1 if count cannot be found
 605          * Takes same arguments as Database::select()
 606          *
 607          * @param string $table
 608          * @param string $vars
 609          * @param string $conds
 610          * @param string $fname
 611          * @param array $options
 612          * @return int
 613          */
 614         function estimateRowCount( $table, $vars = '*', $conds = '',
 615                 $fname = __METHOD__, $options = array()
 616         ) {
 617                 $options['EXPLAIN'] = true;
 618                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 619                 $rows = -1;
 620                 if ( $res ) {
 621                         $row = $this->fetchRow( $res );
 622                         $count = array();
 623                         if ( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 624                                 $rows = (int)$count[1];
 625                         }
 626                 }
 627
 628                 return $rows;
 629         }
 630
 631         /**
 632          * Returns information about an index
 633          * If errors are explicitly ignored, returns NULL on failure
 634          *
 635          * @param string $table
 636          * @param string $index
 637          * @param string $fname
 638          * @return bool|null
 639          */
 640         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 641                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 642                 $res = $this->query( $sql, $fname );
 643                 if ( !$res ) {
 644                         return null;
 645                 }
 646                 foreach ( $res as $row ) {
 647                         if ( $row->indexname == $this->indexName( $index ) ) {
 648                                 return $row;
 649                         }
 650                 }
 651
 652                 return false;
 653         }
 654
 655         /**
 656          * Returns is of attributes used in index
 657          *
 658          * @since 1.19
 659          * @param string $index
 660          * @param bool|string $schema
 661          * @return array
 662          */
 663         function indexAttributes( $index, $schema = false ) {
 664                 if ( $schema === false ) {
 665                         $schema = $this->getCoreSchema();
 666                 }
 667                 /*
 668                  * A subquery would be not needed if we didn't care about the order
 669                  * of attributes, but we do
 670                  */
 671                 $sql = <<<__INDEXATTR__
 672
 673                         SELECT opcname,
 674                                 attname,
 675                                 i.indoption[s.g] as option,
 676                                 pg_am.amname
 677                         FROM
 678                                 (SELECT generate_series(array_lower(isub.indkey,1), array_upper(isub.indkey,1)) AS g
 679                                         FROM
 680                                                 pg_index isub
 681                                         JOIN pg_class cis
 682                                                 ON cis.oid=isub.indexrelid
 683                                         JOIN pg_namespace ns
 684                                                 ON cis.relnamespace = ns.oid
 685                                         WHERE cis.relname='$index' AND ns.nspname='$schema') AS s,
 686                                 pg_attribute,
 687                                 pg_opclass opcls,
 688                                 pg_am,
 689                                 pg_class ci
 690                                 JOIN pg_index i
 691                                         ON ci.oid=i.indexrelid
 692                                 JOIN pg_class ct
 693                                         ON ct.oid = i.indrelid
 694                                 JOIN pg_namespace n
 695                                         ON ci.relnamespace = n.oid
 696                                 WHERE
 697                                         ci.relname='$index' AND n.nspname='$schema'
 698                                         AND     attrelid = ct.oid
 699                                         AND     i.indkey[s.g] = attnum
 700                                         AND     i.indclass[s.g] = opcls.oid
 701                                         AND     pg_am.oid = opcls.opcmethod
 702 __INDEXATTR__;
 703                 $res = $this->query( $sql, __METHOD__ );
 704                 $a = array();
 705                 if ( $res ) {
 706                         foreach ( $res as $row ) {
 707                                 $a[] = array(
 708                                         $row->attname,
 709                                         $row->opcname,
 710                                         $row->amname,
 711                                         $row->option );
 712                         }
 713                 } else {
 714                         return null;
 715                 }
 716
 717                 return $a;
 718         }
 719
 720         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 721                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'" .
 722                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 723                         $this->strencode( $this->indexName( $index ) ) .
 724                         ")'";
 725                 $res = $this->query( $sql, $fname );
 726                 if ( !$res ) {
 727                         return null;
 728                 }
 729
 730                 return $res->numRows() > 0;
 731         }
 732
 733         /**
 734          * Change the FOR UPDATE option as necessary based on the join conditions. Then pass
 735          * to the parent function to get the actual SQL text.
 736          *
 737          * In Postgres when using FOR UPDATE, only the main table and tables that are inner joined
 738          * can be locked. That means tables in an outer join cannot be FOR UPDATE locked. Trying to do
 739          * so causes a DB error. This wrapper checks which tables can be locked and adjusts it accordingly.
 740          *
 741          * MySQL uses "ORDER BY NULL" as an optimization hint, but that syntax is illegal in PostgreSQL.
 742          * @see DatabaseBase::selectSQLText
 743          */
 744         function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
 745                 $options = array(), $join_conds = array()
 746         ) {
 747                 if ( is_array( $options ) ) {
 748                         $forUpdateKey = array_search( 'FOR UPDATE', $options, true );
 749                         if ( $forUpdateKey !== false && $join_conds ) {
 750                                 unset( $options[$forUpdateKey] );
 751
 752                                 foreach ( $join_conds as $table_cond => $join_cond ) {
 753                                         if ( 0 === preg_match( '/^(?:LEFT|RIGHT|FULL)(?: OUTER)? JOIN$/i', $join_cond[0] ) ) {
 754                                                 $options['FOR UPDATE'][] = $table_cond;
 755                                         }
 756                                 }
 757                         }
 758
 759                         if ( isset( $options['ORDER BY'] ) && $options['ORDER BY'] == 'NULL' ) {
 760                                 unset( $options['ORDER BY'] );
 761                         }
 762                 }
 763
 764                 return parent::selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
 765         }
 766
 767         /**
 768          * INSERT wrapper, inserts an array into a table
 769          *
 770          * $args may be a single associative array, or an array of these with numeric keys,
 771          * for multi-row insert (Postgres version 8.2 and above only).
 772          *
 773          * @param string $table Name of the table to insert to.
 774          * @param array $args Items to insert into the table.
 775          * @param string $fname Name of the function, for profiling
 776          * @param array|string $options String or array. Valid options: IGNORE
 777          * @return bool Success of insert operation. IGNORE always returns true.
 778          */
 779         function insert( $table, $args, $fname = __METHOD__, $options = array() ) {
 780                 if ( !count( $args ) ) {
 781                         return true;
 782                 }
 783
 784                 $table = $this->tableName( $table );
 785                 if ( !isset( $this->numericVersion ) ) {
 786                         $this->getServerVersion();
 787                 }
 788
 789                 if ( !is_array( $options ) ) {
 790                         $options = array( $options );
 791                 }
 792
 793                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 794                         $multi = true;
 795                         $keys = array_keys( $args[0] );
 796                 } else {
 797                         $multi = false;
 798                         $keys = array_keys( $args );
 799                 }
 800
 801                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 802                 $savepoint = null;
 803                 if ( in_array( 'IGNORE', $options ) ) {
 804                         $savepoint = new SavepointPostgres( $this, 'mw' );
 805                         $olde = error_reporting( 0 );
 806                         // For future use, we may want to track the number of actual inserts
 807                         // Right now, insert (all writes) simply return true/false
 808                         $numrowsinserted = 0;
 809                 }
 810
 811                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 812
 813                 if ( $multi ) {
 814                         if ( $this->numericVersion >= 8.2 && !$savepoint ) {
 815                                 $first = true;
 816                                 foreach ( $args as $row ) {
 817                                         if ( $first ) {
 818                                                 $first = false;
 819                                         } else {
 820                                                 $sql .= ',';
 821                                         }
 822                                         $sql .= '(' . $this->makeList( $row ) . ')';
 823                                 }
 824                                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 825                         } else {
 826                                 $res = true;
 827                                 $origsql = $sql;
 828                                 foreach ( $args as $row ) {
 829                                         $tempsql = $origsql;
 830                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 831
 832                                         if ( $savepoint ) {
 833                                                 $savepoint->savepoint();
 834                                         }
 835
 836                                         $tempres = (bool)$this->query( $tempsql, $fname, $savepoint );
 837
 838                                         if ( $savepoint ) {
 839                                                 $bar = pg_last_error();
 840                                                 if ( $bar != false ) {
 841                                                         $savepoint->rollback();
 842                                                 } else {
 843                                                         $savepoint->release();
 844                                                         $numrowsinserted++;
 845                                                 }
 846                                         }
 847
 848                                         // If any of them fail, we fail overall for this function call
 849                                         // Note that this will be ignored if IGNORE is set
 850                                         if ( !$tempres ) {
 851                                                 $res = false;
 852                                         }
 853                                 }
 854                         }
 855                 } else {
 856                         // Not multi, just a lone insert
 857                         if ( $savepoint ) {
 858                                 $savepoint->savepoint();
 859                         }
 860
 861                         $sql .= '(' . $this->makeList( $args ) . ')';
 862                         $res = (bool)$this->query( $sql, $fname, $savepoint );
 863                         if ( $savepoint ) {
 864                                 $bar = pg_last_error();
 865                                 if ( $bar != false ) {
 866                                         $savepoint->rollback();
 867                                 } else {
 868                                         $savepoint->release();
 869                                         $numrowsinserted++;
 870                                 }
 871                         }
 872                 }
 873                 if ( $savepoint ) {
 874                         error_reporting( $olde );
 875                         $savepoint->commit();
 876
 877                         // Set the affected row count for the whole operation
 878                         $this->mAffectedRows = $numrowsinserted;
 879
 880                         // IGNORE always returns true
 881                         return true;
 882                 }
 883
 884                 return $res;
 885         }
 886
 887         /**
 888          * INSERT SELECT wrapper
 889          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 890          * Source items may be literals rather then field names, but strings should
 891          * be quoted with Database::addQuotes()
 892          * $conds may be "*" to copy the whole table
 893          * srcTable may be an array of tables.
 894          * @todo FIXME: Implement this a little better (seperate select/insert)?
 895          *
 896          * @param string $destTable
 897          * @param array|string $srcTable
 898          * @param array $varMap
 899          * @param array $conds
 900          * @param string $fname
 901          * @param array $insertOptions
 902          * @param array $selectOptions
 903          * @return bool
 904          */
 905         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = __METHOD__,
 906                 $insertOptions = array(), $selectOptions = array() ) {
 907                 $destTable = $this->tableName( $destTable );
 908
 909                 if ( !is_array( $insertOptions ) ) {
 910                         $insertOptions = array( $insertOptions );
 911                 }
 912
 913                 /*
 914                  * If IGNORE is set, we use savepoints to emulate mysql's behavior
 915                  * Ignore LOW PRIORITY option, since it is MySQL-specific
 916                  */
 917                 $savepoint = null;
 918                 if ( in_array( 'IGNORE', $insertOptions ) ) {
 919                         $savepoint = new SavepointPostgres( $this, 'mw' );
 920                         $olde = error_reporting( 0 );
 921                         $numrowsinserted = 0;
 922                         $savepoint->savepoint();
 923                 }
 924
 925                 if ( !is_array( $selectOptions ) ) {
 926                         $selectOptions = array( $selectOptions );
 927                 }
 928                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
 929                 if ( is_array( $srcTable ) ) {
 930                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
 931                 } else {
 932                         $srcTable = $this->tableName( $srcTable );
 933                 }
 934
 935                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 936                         " SELECT $startOpts " . implode( ',', $varMap ) .
 937                         " FROM $srcTable $useIndex";
 938
 939                 if ( $conds != '*' ) {
 940                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 941                 }
 942
 943                 $sql .= " $tailOpts";
 944
 945                 $res = (bool)$this->query( $sql, $fname, $savepoint );
 946                 if ( $savepoint ) {
 947                         $bar = pg_last_error();
 948                         if ( $bar != false ) {
 949                                 $savepoint->rollback();
 950                         } else {
 951                                 $savepoint->release();
 952                                 $numrowsinserted++;
 953                         }
 954                         error_reporting( $olde );
 955                         $savepoint->commit();
 956
 957                         // Set the affected row count for the whole operation
 958                         $this->mAffectedRows = $numrowsinserted;
 959
 960                         // IGNORE always returns true
 961                         return true;
 962                 }
 963
 964                 return $res;
 965         }
 966
 967         function tableName( $name, $format = 'quoted' ) {
 968                 # Replace reserved words with better ones
 969                 switch ( $name ) {
 970                         case 'user':
 971                                 return $this->realTableName( 'mwuser', $format );
 972                         case 'text':
 973                                 return $this->realTableName( 'pagecontent', $format );
 974                         default:
 975                                 return $this->realTableName( $name, $format );
 976                 }
 977         }
 978
 979         /* Don't cheat on installer */
 980         function realTableName( $name, $format = 'quoted' ) {
 981                 return parent::tableName( $name, $format );
 982         }
 983
 984         /**
 985          * Return the next in a sequence, save the value for retrieval via insertId()
 986          *
 987          * @param string $seqName
 988          * @return int|null
 989          */
 990         function nextSequenceValue( $seqName ) {
 991                 $safeseq = str_replace( "'", "''", $seqName );
 992                 $res = $this->query( "SELECT nextval('$safeseq')" );
 993                 $row = $this->fetchRow( $res );
 994                 $this->mInsertId = $row[0];
 995
 996                 return $this->mInsertId;
 997         }
 998
 999         /**
1000          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
1001          *
1002          * @param string $seqName
1003          * @return int
1004          */
1005         function currentSequenceValue( $seqName ) {
1006                 $safeseq = str_replace( "'", "''", $seqName );
1007                 $res = $this->query( "SELECT currval('$safeseq')" );
1008                 $row = $this->fetchRow( $res );
1009                 $currval = $row[0];
1010
1011                 return $currval;
1012         }
1013
1014         # Returns the size of a text field, or -1 for "unlimited"
1015         function textFieldSize( $table, $field ) {
1016                 $table = $this->tableName( $table );
1017                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1018                         FROM pg_class c, pg_attribute a, pg_type t
1019                         WHERE relname='$table' AND a.attrelid=c.oid AND
1020                                 a.atttypid=t.oid and a.attname='$field'";
1021                 $res = $this->query( $sql );
1022                 $row = $this->fetchObject( $res );
1023                 if ( $row->ftype == 'varchar' ) {
1024                         $size = $row->size - 4;
1025                 } else {
1026                         $size = $row->size;
1027                 }
1028
1029                 return $size;
1030         }
1031
1032         function limitResult( $sql, $limit, $offset = false ) {
1033                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1034         }
1035
1036         function wasDeadlock() {
1037                 return $this->lastErrno() == '40P01';
1038         }
1039
1040         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
1041                 $newName = $this->addIdentifierQuotes( $newName );
1042                 $oldName = $this->addIdentifierQuotes( $oldName );
1043
1044                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName " .
1045                         "(LIKE $oldName INCLUDING DEFAULTS)", $fname );
1046         }
1047
1048         function listTables( $prefix = null, $fname = __METHOD__ ) {
1049                 $eschema = $this->addQuotes( $this->getCoreSchema() );
1050                 $result = $this->query( "SELECT tablename FROM pg_tables WHERE schemaname = $eschema", $fname );
1051                 $endArray = array();
1052
1053                 foreach ( $result as $table ) {
1054                         $vars = get_object_vars( $table );
1055                         $table = array_pop( $vars );
1056                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1057                                 $endArray[] = $table;
1058                         }
1059                 }
1060
1061                 return $endArray;
1062         }
1063
1064         function timestamp( $ts = 0 ) {
1065                 return wfTimestamp( TS_POSTGRES, $ts );
1066         }
1067
1068         /**
1069          * Posted by cc[plus]php[at]c2se[dot]com on 25-Mar-2009 09:12
1070          * to http://www.php.net/manual/en/ref.pgsql.php
1071          *
1072          * Parsing a postgres array can be a tricky problem, he's my
1073          * take on this, it handles multi-dimensional arrays plus
1074          * escaping using a nasty regexp to determine the limits of each
1075          * data-item.
1076          *
1077          * This should really be handled by PHP PostgreSQL module
1078          *
1079          * @since 1.19
1080          * @param string $text Postgreql array returned in a text form like {a,b}
1081          * @param string $output
1082          * @param int $limit
1083          * @param int $offset
1084          * @return string
1085          */
1086         function pg_array_parse( $text, &$output, $limit = false, $offset = 1 ) {
1087                 if ( false === $limit ) {
1088                         $limit = strlen( $text ) - 1;
1089                         $output = array();
1090                 }
1091                 if ( '{}' == $text ) {
1092                         return $output;
1093                 }
1094                 do {
1095                         if ( '{' != $text[$offset] ) {
1096                                 preg_match( "/(\\{?\"([^\"\\\\]|\\\\.)*\"|[^,{}]+)+([,}]+)/",
1097                                         $text, $match, 0, $offset );
1098                                 $offset += strlen( $match[0] );
1099                                 $output[] = ( '"' != $match[1][0]
1100                                         ? $match[1]
1101                                         : stripcslashes( substr( $match[1], 1, -1 ) ) );
1102                                 if ( '},' == $match[3] ) {
1103                                         return $output;
1104                                 }
1105                         } else {
1106                                 $offset = $this->pg_array_parse( $text, $output, $limit, $offset + 1 );
1107                         }
1108                 } while ( $limit > $offset );
1109
1110                 return $output;
1111         }
1112
1113         /**
1114          * Return aggregated value function call
1115          * @param array $valuedata
1116          * @param string $valuename
1117          * @return array
1118          */
1119         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1120                 return $valuedata;
1121         }
1122
1123         /**
1124          * @return string Wikitext of a link to the server software's web site
1125          */
1126         public function getSoftwareLink() {
1127                 return '[{{int:version-db-postgres-url}} PostgreSQL]';
1128         }
1129
1130         /**
1131          * Return current schema (executes SELECT current_schema())
1132          * Needs transaction
1133          *
1134          * @since 1.19
1135          * @return string Default schema for the current session
1136          */
1137         function getCurrentSchema() {
1138                 $res = $this->query( "SELECT current_schema()", __METHOD__ );
1139                 $row = $this->fetchRow( $res );
1140
1141                 return $row[0];
1142         }
1143
1144         /**
1145          * Return list of schemas which are accessible without schema name
1146          * This is list does not contain magic keywords like "$user"
1147          * Needs transaction
1148          *
1149          * @see getSearchPath()
1150          * @see setSearchPath()
1151          * @since 1.19
1152          * @return array List of actual schemas for the current sesson
1153          */
1154         function getSchemas() {
1155                 $res = $this->query( "SELECT current_schemas(false)", __METHOD__ );
1156                 $row = $this->fetchRow( $res );
1157                 $schemas = array();
1158
1159                 /* PHP pgsql support does not support array type, "{a,b}" string is returned */
1160
1161                 return $this->pg_array_parse( $row[0], $schemas );
1162         }
1163
1164         /**
1165          * Return search patch for schemas
1166          * This is different from getSchemas() since it contain magic keywords
1167          * (like "$user").
1168          * Needs transaction
1169          *
1170          * @since 1.19
1171          * @return array How to search for table names schemas for the current user
1172          */
1173         function getSearchPath() {
1174                 $res = $this->query( "SHOW search_path", __METHOD__ );
1175                 $row = $this->fetchRow( $res );
1176
1177                 /* PostgreSQL returns SHOW values as strings */
1178
1179                 return explode( ",", $row[0] );
1180         }
1181
1182         /**
1183          * Update search_path, values should already be sanitized
1184          * Values may contain magic keywords like "$user"
1185          * @since 1.19
1186          *
1187          * @param array $search_path List of schemas to be searched by default
1188          */
1189         function setSearchPath( $search_path ) {
1190                 $this->query( "SET search_path = " . implode( ", ", $search_path ) );
1191         }
1192
1193         /**
1194          * Determine default schema for MediaWiki core
1195          * Adjust this session schema search path if desired schema exists
1196          * and is not alread there.
1197          *
1198          * We need to have name of the core schema stored to be able
1199          * to query database metadata.
1200          *
1201          * This will be also called by the installer after the schema is created
1202          *
1203          * @since 1.19
1204          *
1205          * @param string $desiredSchema
1206          */
1207         function determineCoreSchema( $desiredSchema ) {
1208                 $this->begin( __METHOD__ );
1209                 if ( $this->schemaExists( $desiredSchema ) ) {
1210                         if ( in_array( $desiredSchema, $this->getSchemas() ) ) {
1211                                 $this->mCoreSchema = $desiredSchema;
1212                                 wfDebug( "Schema \"" . $desiredSchema . "\" already in the search path\n" );
1213                         } else {
1214                                 /**
1215                                  * Prepend our schema (e.g. 'mediawiki') in front
1216                                  * of the search path
1217                                  * Fixes bug 15816
1218                                  */
1219                                 $search_path = $this->getSearchPath();
1220                                 array_unshift( $search_path,
1221                                         $this->addIdentifierQuotes( $desiredSchema ) );
1222                                 $this->setSearchPath( $search_path );
1223                                 $this->mCoreSchema = $desiredSchema;
1224                                 wfDebug( "Schema \"" . $desiredSchema . "\" added to the search path\n" );
1225                         }
1226                 } else {
1227                         $this->mCoreSchema = $this->getCurrentSchema();
1228                         wfDebug( "Schema \"" . $desiredSchema . "\" not found, using current \"" .
1229                                 $this->mCoreSchema . "\"\n" );
1230                 }
1231                 /* Commit SET otherwise it will be rollbacked on error or IGNORE SELECT */
1232                 $this->commit( __METHOD__ );
1233         }
1234
1235         /**
1236          * Return schema name fore core MediaWiki tables
1237          *
1238          * @since 1.19
1239          * @return string Core schema name
1240          */
1241         function getCoreSchema() {
1242                 return $this->mCoreSchema;
1243         }
1244
1245         /**
1246          * @return string Version information from the database
1247          */
1248         function getServerVersion() {
1249                 if ( !isset( $this->numericVersion ) ) {
1250                         $versionInfo = pg_version( $this->mConn );
1251                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1252                                 // Old client, abort install
1253                                 $this->numericVersion = '7.3 or earlier';
1254                         } elseif ( isset( $versionInfo['server'] ) ) {
1255                                 // Normal client
1256                                 $this->numericVersion = $versionInfo['server'];
1257                         } else {
1258                                 // Bug 16937: broken pgsql extension from PHP<5.3
1259                                 $this->numericVersion = pg_parameter_status( $this->mConn, 'server_version' );
1260                         }
1261                 }
1262
1263                 return $this->numericVersion;
1264         }
1265
1266         /**
1267          * Query whether a given relation exists (in the given schema, or the
1268          * default mw one if not given)
1269          * @param string $table
1270          * @param array|string $types
1271          * @param bool|string $schema
1272          * @return bool
1273          */
1274         function relationExists( $table, $types, $schema = false ) {
1275                 if ( !is_array( $types ) ) {
1276                         $types = array( $types );
1277                 }
1278                 if ( !$schema ) {
1279                         $schema = $this->getCoreSchema();
1280                 }
1281                 $table = $this->realTableName( $table, 'raw' );
1282                 $etable = $this->addQuotes( $table );
1283                 $eschema = $this->addQuotes( $schema );
1284                 $sql = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1285                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1286                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1287                 $res = $this->query( $sql );
1288                 $count = $res ? $res->numRows() : 0;
1289
1290                 return (bool)$count;
1291         }
1292
1293         /**
1294          * For backward compatibility, this function checks both tables and
1295          * views.
1296          * @param string $table
1297          * @param string $fname
1298          * @param bool|string $schema
1299          * @return bool
1300          */
1301         function tableExists( $table, $fname = __METHOD__, $schema = false ) {
1302                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1303         }
1304
1305         function sequenceExists( $sequence, $schema = false ) {
1306                 return $this->relationExists( $sequence, 'S', $schema );
1307         }
1308
1309         function triggerExists( $table, $trigger ) {
1310                 $q = <<<SQL
1311         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1312                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1313                           AND tgrelid=pg_class.oid
1314                           AND nspname=%s AND relname=%s AND tgname=%s
1315 SQL;
1316                 $res = $this->query(
1317                         sprintf(
1318                                 $q,
1319                                 $this->addQuotes( $this->getCoreSchema() ),
1320                                 $this->addQuotes( $table ),
1321                                 $this->addQuotes( $trigger )
1322                         )
1323                 );
1324                 if ( !$res ) {
1325                         return null;
1326                 }
1327                 $rows = $res->numRows();
1328
1329                 return $rows;
1330         }
1331
1332         function ruleExists( $table, $rule ) {
1333                 $exists = $this->selectField( 'pg_rules', 'rulename',
1334                         array(
1335                                 'rulename' => $rule,
1336                                 'tablename' => $table,
1337                                 'schemaname' => $this->getCoreSchema()
1338                         )
1339                 );
1340
1341                 return $exists === $rule;
1342         }
1343
1344         function constraintExists( $table, $constraint ) {
1345                 $sql = sprintf( "SELECT 1 FROM information_schema.table_constraints " .
1346                         "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1347                         $this->addQuotes( $this->getCoreSchema() ),
1348                         $this->addQuotes( $table ),
1349                         $this->addQuotes( $constraint )
1350                 );
1351                 $res = $this->query( $sql );
1352                 if ( !$res ) {
1353                         return null;
1354                 }
1355                 $rows = $res->numRows();
1356
1357                 return $rows;
1358         }
1359
1360         /**
1361          * Query whether a given schema exists. Returns true if it does, false if it doesn't.
1362          * @param string $schema
1363          * @return bool
1364          */
1365         function schemaExists( $schema ) {
1366                 $exists = $this->selectField( '"pg_catalog"."pg_namespace"', 1,
1367                         array( 'nspname' => $schema ), __METHOD__ );
1368
1369                 return (bool)$exists;
1370         }
1371
1372         /**
1373          * Returns true if a given role (i.e. user) exists, false otherwise.
1374          * @param string $roleName
1375          * @return bool
1376          */
1377         function roleExists( $roleName ) {
1378                 $exists = $this->selectField( '"pg_catalog"."pg_roles"', 1,
1379                         array( 'rolname' => $roleName ), __METHOD__ );
1380
1381                 return (bool)$exists;
1382         }
1383
1384         function fieldInfo( $table, $field ) {
1385                 return PostgresField::fromText( $this, $table, $field );
1386         }
1387
1388         /**
1389          * pg_field_type() wrapper
1390          * @param ResultWrapper|resource $res ResultWrapper or PostgreSQL query result resource
1391          * @param int $index Field number, starting from 0
1392          * @return string
1393          */
1394         function fieldType( $res, $index ) {
1395                 if ( $res instanceof ResultWrapper ) {
1396                         $res = $res->result;
1397                 }
1398
1399                 return pg_field_type( $res, $index );
1400         }
1401
1402         /**
1403          * @param string $b
1404          * @return Blob
1405          */
1406         function encodeBlob( $b ) {
1407                 return new PostgresBlob( pg_escape_bytea( $b ) );
1408         }
1409
1410         function decodeBlob( $b ) {
1411                 if ( $b instanceof PostgresBlob ) {
1412                         $b = $b->fetch();
1413                 } elseif ( $b instanceof Blob ) {
1414                         return $b->fetch();
1415                 }
1416
1417                 return pg_unescape_bytea( $b );
1418         }
1419
1420         function strencode( $s ) {
1421                 // Should not be called by us
1422
1423                 return pg_escape_string( $this->mConn, $s );
1424         }
1425
1426         /**
1427          * @param null|bool|Blob $s
1428          * @return int|string
1429          */
1430         function addQuotes( $s ) {
1431                 if ( is_null( $s ) ) {
1432                         return 'NULL';
1433                 } elseif ( is_bool( $s ) ) {
1434                         return intval( $s );
1435                 } elseif ( $s instanceof Blob ) {
1436                         if ( $s instanceof PostgresBlob ) {
1437                                 $s = $s->fetch();
1438                         } else {
1439                                 $s = pg_escape_bytea( $this->mConn, $s->fetch() );
1440                         }
1441                         return "'$s'";
1442                 }
1443
1444                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1445         }
1446
1447         /**
1448          * Postgres specific version of replaceVars.
1449          * Calls the parent version in Database.php
1450          *
1451          * @param string $ins SQL string, read from a stream (usually tables.sql)
1452          * @return string SQL string
1453          */
1454         protected function replaceVars( $ins ) {
1455                 $ins = parent::replaceVars( $ins );
1456
1457                 if ( $this->numericVersion >= 8.3 ) {
1458                         // Thanks for not providing backwards-compatibility, 8.3
1459                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1460                 }
1461
1462                 if ( $this->numericVersion <= 8.1 ) { // Our minimum version
1463                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1464                 }
1465
1466                 return $ins;
1467         }
1468
1469         /**
1470          * Various select options
1471          *
1472          * @param array $options An associative array of options to be turned into
1473          *   an SQL query, valid keys are listed in the function.
1474          * @return array
1475          */
1476         function makeSelectOptions( $options ) {
1477                 $preLimitTail = $postLimitTail = '';
1478                 $startOpts = $useIndex = '';
1479
1480                 $noKeyOptions = array();
1481                 foreach ( $options as $key => $option ) {
1482                         if ( is_numeric( $key ) ) {
1483                                 $noKeyOptions[$option] = true;
1484                         }
1485                 }
1486
1487                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1488
1489                 $preLimitTail .= $this->makeOrderBy( $options );
1490
1491                 // if ( isset( $options['LIMIT'] ) ) {
1492                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1493                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1494                 //              : false );
1495                 // }
1496
1497                 if ( isset( $options['FOR UPDATE'] ) ) {
1498                         $postLimitTail .= ' FOR UPDATE OF ' .
1499                                 implode( ', ', array_map( array( &$this, 'tableName' ), $options['FOR UPDATE'] ) );
1500                 } elseif ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1501                         $postLimitTail .= ' FOR UPDATE';
1502                 }
1503
1504                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1505                         $startOpts .= 'DISTINCT';
1506                 }
1507
1508                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1509         }
1510
1511         function getDBname() {
1512                 return $this->mDBname;
1513         }
1514
1515         function getServer() {
1516                 return $this->mServer;
1517         }
1518
1519         function buildConcat( $stringList ) {
1520                 return implode( ' || ', $stringList );
1521         }
1522
1523         public function buildGroupConcatField(
1524                 $delimiter, $table, $field, $conds = '', $options = array(), $join_conds = array()
1525         ) {
1526                 $fld = "array_to_string(array_agg($field)," . $this->addQuotes( $delimiter ) . ')';
1527
1528                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, array(), $join_conds ) . ')';
1529         }
1530
1531         public function getSearchEngine() {
1532                 return 'SearchPostgres';
1533         }
1534
1535         public function streamStatementEnd( &$sql, &$newLine ) {
1536                 # Allow dollar quoting for function declarations
1537                 if ( substr( $newLine, 0, 4 ) == '$mw$' ) {
1538                         if ( $this->delimiter ) {
1539                                 $this->delimiter = false;
1540                         } else {
1541                                 $this->delimiter = ';';
1542                         }
1543                 }
1544
1545                 return parent::streamStatementEnd( $sql, $newLine );
1546         }
1547
1548         /**
1549          * Check to see if a named lock is available. This is non-blocking.
1550          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1551          *
1552          * @param string $lockName Name of lock to poll
1553          * @param string $method Name of method calling us
1554          * @return bool
1555          * @since 1.20
1556          */
1557         public function lockIsFree( $lockName, $method ) {
1558                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1559                 $result = $this->query( "SELECT (CASE(pg_try_advisory_lock($key))
1560                         WHEN 'f' THEN 'f' ELSE pg_advisory_unlock($key) END) AS lockstatus", $method );
1561                 $row = $this->fetchObject( $result );
1562
1563                 return ( $row->lockstatus === 't' );
1564         }
1565
1566         /**
1567          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1568          * @param string $lockName
1569          * @param string $method
1570          * @param int $timeout
1571          * @return bool
1572          */
1573         public function lock( $lockName, $method, $timeout = 5 ) {
1574                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1575                 for ( $attempts = 1; $attempts <= $timeout; ++$attempts ) {
1576                         $result = $this->query(
1577                                 "SELECT pg_try_advisory_lock($key) AS lockstatus", $method );
1578                         $row = $this->fetchObject( $result );
1579                         if ( $row->lockstatus === 't' ) {
1580                                 return true;
1581                         } else {
1582                                 sleep( 1 );
1583                         }
1584                 }
1585                 wfDebug( __METHOD__ . " failed to acquire lock\n" );
1586
1587                 return false;
1588         }
1589
1590         /**
1591          * See http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKSFROM
1592          * PG DOCS: http://www.postgresql.org/docs/8.2/static/functions-admin.html#FUNCTIONS-ADVISORY-LOCKS
1593          * @param string $lockName
1594          * @param string $method
1595          * @return bool
1596          */
1597         public function unlock( $lockName, $method ) {
1598                 $key = $this->addQuotes( $this->bigintFromLockName( $lockName ) );
1599                 $result = $this->query( "SELECT pg_advisory_unlock($key) as lockstatus", $method );
1600                 $row = $this->fetchObject( $result );
1601
1602                 return ( $row->lockstatus === 't' );
1603         }
1604
1605         /**
1606          * @param string $lockName
1607          * @return string Integer
1608          */
1609         private function bigintFromLockName( $lockName ) {
1610                 return wfBaseConvert( substr( sha1( $lockName ), 0, 15 ), 16, 10 );
1611         }
1612 } // end DatabasePostgres class
1613
1614 class PostgresBlob extends Blob {
1615 }