includes/db/DatabasePostgres.php

   1 <?php
   2 /**
   3  * This is the Postgres database abstraction layer.
   4  *
   5  * @file
   6  * @ingroup Database
   7  */
   8
   9 class PostgresField implements Field {
  10         private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname;
  11
  12         static function fromText($db, $table, $field) {
  13         global $wgDBmwschema;
  14
  15                 $q = <<<SQL
  16 SELECT
  17  attnotnull, attlen, COALESCE(conname, '') AS conname,
  18  COALESCE(condeferred, 'f') AS deferred,
  19  COALESCE(condeferrable, 'f') AS deferrable,
  20  CASE WHEN typname = 'int2' THEN 'smallint'
  21   WHEN typname = 'int4' THEN 'integer'
  22   WHEN typname = 'int8' THEN 'bigint'
  23   WHEN typname = 'bpchar' THEN 'char'
  24  ELSE typname END AS typname
  25 FROM pg_class c
  26 JOIN pg_namespace n ON (n.oid = c.relnamespace)
  27 JOIN pg_attribute a ON (a.attrelid = c.oid)
  28 JOIN pg_type t ON (t.oid = a.atttypid)
  29 LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
  30 WHERE relkind = 'r'
  31 AND nspname=%s
  32 AND relname=%s
  33 AND attname=%s;
  34 SQL;
  35
  36                 $table = $db->tableName( $table );
  37                 $res = $db->query(
  38                         sprintf( $q,
  39                                 $db->addQuotes( $wgDBmwschema ),
  40                                 $db->addQuotes( $table ),
  41                                 $db->addQuotes( $field )
  42                         )
  43                 );
  44                 $row = $db->fetchObject( $res );
  45                 if ( !$row ) {
  46                         return null;
  47                 }
  48                 $n = new PostgresField;
  49                 $n->type = $row->typname;
  50                 $n->nullable = ( $row->attnotnull == 'f' );
  51                 $n->name = $field;
  52                 $n->tablename = $table;
  53                 $n->max_length = $row->attlen;
  54                 $n->deferrable = ( $row->deferrable == 't' );
  55                 $n->deferred = ( $row->deferred == 't' );
  56                 $n->conname = $row->conname;
  57                 return $n;
  58         }
  59
  60         function name() {
  61                 return $this->name;
  62         }
  63
  64         function tableName() {
  65                 return $this->tablename;
  66         }
  67
  68         function type() {
  69                 return $this->type;
  70         }
  71
  72         function isNullable() {
  73                 return $this->nullable;
  74         }
  75
  76         function maxLength() {
  77                 return $this->max_length;
  78         }
  79
  80         function is_deferrable() {
  81                 return $this->deferrable;
  82         }
  83
  84         function is_deferred() {
  85                 return $this->deferred;
  86         }
  87
  88         function conname() {
  89                 return $this->conname;
  90         }
  91
  92 }
  93
  94 /**
  95  * @ingroup Database
  96  */
  97 class DatabasePostgres extends DatabaseBase {
  98         var $mInsertId = null;
  99         var $mLastResult = null;
 100         var $numeric_version = null;
 101         var $mAffectedRows = null;
 102
 103         function getType() {
 104                 return 'postgres';
 105         }
 106
 107         function cascadingDeletes() {
 108                 return true;
 109         }
 110         function cleanupTriggers() {
 111                 return true;
 112         }
 113         function strictIPs() {
 114                 return true;
 115         }
 116         function realTimestamps() {
 117                 return true;
 118         }
 119         function implicitGroupby() {
 120                 return false;
 121         }
 122         function implicitOrderby() {
 123                 return false;
 124         }
 125         function searchableIPs() {
 126                 return true;
 127         }
 128         function functionalIndexes() {
 129                 return true;
 130         }
 131
 132         function hasConstraint( $name ) {
 133                 global $wgDBmwschema;
 134                 $SQL = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n WHERE c.connamespace = n.oid AND conname = '" .
 135                                 pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" . pg_escape_string( $this->mConn, $wgDBmwschema ) ."'";
 136                 $res = $this->doQuery( $SQL );
 137                 return $this->numRows( $res );
 138         }
 139
 140         /**
 141          * Usually aborts on failure
 142          */
 143         function open( $server, $user, $password, $dbName ) {
 144                 # Test for Postgres support, to avoid suppressed fatal error
 145                 if ( !function_exists( 'pg_connect' ) ) {
 146                         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" );
 147                 }
 148
 149                 global $wgDBport;
 150
 151                 if ( !strlen( $user ) ) { # e.g. the class is being loaded
 152                         return;
 153                 }
 154                 $this->close();
 155                 $this->mServer = $server;
 156                 $this->mPort = $port = $wgDBport;
 157                 $this->mUser = $user;
 158                 $this->mPassword = $password;
 159                 $this->mDBname = $dbName;
 160
 161                 $connectVars = array(
 162                         'dbname' => $dbName,
 163                         'user' => $user,
 164                         'password' => $password
 165                 );
 166                 if ( $server != false && $server != '' ) {
 167                         $connectVars['host'] = $server;
 168                 }
 169                 if ( $port != false && $port != '' ) {
 170                         $connectVars['port'] = $port;
 171                 }
 172                 $connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );
 173
 174                 $this->installErrorHandler();
 175                 $this->mConn = pg_connect( $connectString );
 176                 $phpError = $this->restoreErrorHandler();
 177
 178                 if ( !$this->mConn ) {
 179                         wfDebug( "DB connection error\n" );
 180                         wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
 181                         wfDebug( $this->lastError() . "\n" );
 182                         throw new DBConnectionError( $this, $phpError );
 183                 }
 184
 185                 $this->mOpened = true;
 186
 187                 global $wgCommandLineMode;
 188                 # If called from the command-line (e.g. importDump), only show errors
 189                 if ( $wgCommandLineMode ) {
 190                         $this->doQuery( "SET client_min_messages = 'ERROR'" );
 191                 }
 192
 193                 $this->doQuery( "SET client_encoding='UTF8'" );
 194
 195                 global $wgDBmwschema, $wgDBts2schema;
 196                 if ( isset( $wgDBmwschema ) && isset( $wgDBts2schema )
 197                         && $wgDBmwschema !== 'mediawiki'
 198                         && preg_match( '/^\w+$/', $wgDBmwschema )
 199                         && preg_match( '/^\w+$/', $wgDBts2schema )
 200                 ) {
 201                         $safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
 202                         $this->doQuery( "SET search_path = $safeschema, $wgDBts2schema, public" );
 203                 }
 204
 205                 return $this->mConn;
 206         }
 207
 208         function makeConnectionString( $vars ) {
 209                 $s = '';
 210                 foreach ( $vars as $name => $value ) {
 211                         $s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
 212                 }
 213                 return $s;
 214         }
 215
 216
 217         function initial_setup( $superuser, $password, $dbName ) {
 218                 // If this is the initial connection, setup the schema stuff and possibly create the user
 219                 global $wgDBname, $wgDBuser, $wgDBpassword, $wgDBmwschema, $wgDBts2schema;
 220
 221                 $safeuser = $this->addIdentifierQuotes( $wgDBuser );
 222                 // Are we connecting as a superuser for the first time?
 223                 if ( $superuser ) {
 224                         // Are we really a superuser? Check out our rights
 225                         $SQL = "SELECT
 226                       CASE WHEN usesuper IS TRUE THEN
 227                       CASE WHEN usecreatedb IS TRUE THEN 3 ELSE 1 END
 228                       ELSE CASE WHEN usecreatedb IS TRUE THEN 2 ELSE 0 END
 229                     END AS rights
 230                     FROM pg_catalog.pg_user WHERE usename = " . $this->addQuotes( $superuser );
 231                         $rows = $this->numRows( $res = $this->doQuery( $SQL ) );
 232                         if ( !$rows ) {
 233                                 print '<li>ERROR: Could not read permissions for user "' . htmlspecialchars( $superuser ) . "\"</li>\n";
 234                                 dieout( );
 235                         }
 236                         $perms = pg_fetch_result( $res, 0, 0 );
 237
 238                         $SQL = "SELECT 1 FROM pg_catalog.pg_user WHERE usename = " . $this->addQuotes( $wgDBuser );
 239                         $rows = $this->numRows( $this->doQuery( $SQL ) );
 240                         if ( $rows ) {
 241                                 print '<li>User "' . htmlspecialchars( $wgDBuser ) . '" already exists, skipping account creation.</li>';
 242                         } else {
 243                                 if ( $perms != 1 && $perms != 3 ) {
 244                                         print '<li>ERROR: the user "' . htmlspecialchars( $superuser ) . '" cannot create other users. ';
 245                                         print 'Please use a different Postgres user.</li>';
 246                                         dieout( );
 247                                 }
 248                                 print '<li>Creating user <b>' . htmlspecialchars( $wgDBuser ) . '</b>...';
 249                                 $safepass = $this->addQuotes( $wgDBpassword );
 250                                 $SQL = "CREATE USER $safeuser NOCREATEDB PASSWORD $safepass";
 251                                 $this->doQuery( $SQL );
 252                                 print "OK</li>\n";
 253                         }
 254                         // User now exists, check out the database
 255                         if ( $dbName != $wgDBname ) {
 256                                 $SQL = "SELECT 1 FROM pg_catalog.pg_database WHERE datname = " . $this->addQuotes( $wgDBname );
 257                                 $rows = $this->numRows( $this->doQuery( $SQL ) );
 258                                 if ( $rows ) {
 259                                         print '<li>Database "' . htmlspecialchars( $wgDBname ) . '" already exists, skipping database creation.</li>';
 260                                 } else {
 261                                         if ( $perms < 1 ) {
 262                                                 print '<li>ERROR: the user "' . htmlspecialchars( $superuser ) . '" cannot create databases. ';
 263                                                 print 'Please use a different Postgres user.</li>';
 264                                                 dieout( );
 265                                         }
 266                                         print '<li>Creating database <b>' . htmlspecialchars( $wgDBname ) . '</b>...';
 267                                         $safename = $this->addIdentifierQuotes( $wgDBname );
 268                                         $SQL = "CREATE DATABASE $safename OWNER $safeuser ";
 269                                         $this->doQuery( $SQL );
 270                                         print "OK</li>\n";
 271                                         // Hopefully tsearch2 and plpgsql are in template1...
 272                                 }
 273
 274                                 // Reconnect to check out tsearch2 rights for this user
 275                                 print '<li>Connecting to "' . htmlspecialchars( $wgDBname ) . '" as superuser "' .
 276                                         htmlspecialchars( $superuser ) . '" to check rights...';
 277
 278                                 $connectVars = array();
 279                                 if ( $this->mServer != false && $this->mServer != '' ) {
 280                                         $connectVars['host'] = $this->mServer;
 281                                 }
 282                                 if ( $this->mPort != false && $this->mPort != '' ) {
 283                                         $connectVars['port'] = $this->mPort;
 284                                 }
 285                                 $connectVars['dbname'] = $wgDBname;
 286                                 $connectVars['user'] = $superuser;
 287                                 $connectVars['password'] = $password;
 288
 289                                 @$this->mConn = pg_connect( $this->makeConnectionString( $connectVars ) );
 290                                 if ( !$this->mConn ) {
 291                                         print "<b>FAILED TO CONNECT!</b></li>";
 292                                         dieout( );
 293                                 }
 294                                 print "OK</li>\n";
 295                         }
 296
 297                         if ( $this->numeric_version < 8.3 ) {
 298                                 // Tsearch2 checks
 299                                 print '<li>Checking that tsearch2 is installed in the database "' .
 300                                         htmlspecialchars( $wgDBname ) . '"...';
 301                                 if ( !$this->tableExists( 'pg_ts_cfg', $wgDBts2schema ) ) {
 302                                         print '<b>FAILED</b>. tsearch2 must be installed in the database "' .
 303                                                 htmlspecialchars( $wgDBname ) . '".';
 304                                         print 'Please see <a href="http://www.devx.com/opensource/Article/21674/0/page/2">this article</a>';
 305                                         print " for instructions or ask on #postgresql on irc.freenode.net</li>\n";
 306                                         dieout( );
 307                                 }
 308                                 print "OK</li>\n";
 309                                 print '<li>Ensuring that user "' . htmlspecialchars( $wgDBuser ) .
 310                                         '" has select rights on the tsearch2 tables...';
 311                                 foreach ( array( 'cfg', 'cfgmap', 'dict', 'parser' ) as $table ) {
 312                                         $SQL = "GRANT SELECT ON pg_ts_$table TO $safeuser";
 313                                         $this->doQuery( $SQL );
 314                                 }
 315                                 print "OK</li>\n";
 316                         }
 317
 318                         // Setup the schema for this user if needed
 319                         $result = $this->schemaExists( $wgDBmwschema );
 320                         $safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
 321                         if ( !$result ) {
 322                                 print '<li>Creating schema <b>' . htmlspecialchars( $wgDBmwschema ) . '</b> ...';
 323                                 $result = $this->doQuery( "CREATE SCHEMA $safeschema AUTHORIZATION $safeuser" );
 324                                 if ( !$result ) {
 325                                         print "<b>FAILED</b>.</li>\n";
 326                                         dieout( );
 327                                 }
 328                                 print "OK</li>\n";
 329                         } else {
 330                                 print "<li>Schema already exists, explicitly granting rights...\n";
 331                                 $safeschema2 = $this->addQuotes( $wgDBmwschema );
 332                                 $SQL = "SELECT 'GRANT ALL ON '||pg_catalog.quote_ident(relname)||' TO $safeuser;'\n".
 333                                         "FROM pg_catalog.pg_class p, pg_catalog.pg_namespace n\n".
 334                                         "WHERE relnamespace = n.oid AND n.nspname = $safeschema2\n".
 335                                         "AND p.relkind IN ('r','S','v')\n";
 336                                 $SQL .= "UNION\n";
 337                                 $SQL .= "SELECT 'GRANT ALL ON FUNCTION '||pg_catalog.quote_ident(proname)||'('||\n".
 338                                         "pg_catalog.oidvectortypes(p.proargtypes)||') TO $safeuser;'\n".
 339                                         "FROM pg_catalog.pg_proc p, pg_catalog.pg_namespace n\n".
 340                                         "WHERE p.pronamespace = n.oid AND n.nspname = $safeschema2";
 341                                 $res = $this->doQuery( $SQL );
 342                                 if ( !$res ) {
 343                                         print "<b>FAILED</b>. Could not set rights for the user.</li>\n";
 344                                         dieout( );
 345                                 }
 346                                 $this->doQuery( "SET search_path = $safeschema" );
 347                                 $rows = $this->numRows( $res );
 348                                 while ( $rows ) {
 349                                         $rows--;
 350                                         $this->doQuery( pg_fetch_result( $res, $rows, 0 ) );
 351                                 }
 352                                 print "OK</li>";
 353                         }
 354
 355                         // Install plpgsql if needed
 356                         $this->setup_plpgsql();
 357
 358                         return true; // Reconnect as regular user
 359
 360                 } // end superuser
 361
 362                 if ( !defined( 'POSTGRES_SEARCHPATH' ) ) {
 363
 364                         if ( $this->numeric_version < 8.3 ) {
 365                                 // Do we have the basic tsearch2 table?
 366                                 print '<li>Checking for tsearch2 in the schema "' . htmlspecialchars( $wgDBts2schema ) . '"...';
 367                                 if ( !$this->tableExists( 'pg_ts_dict', $wgDBts2schema ) ) {
 368                                         print '<b>FAILED</b>. Make sure tsearch2 is installed. See <a href="';
 369                                         print 'http://www.devx.com/opensource/Article/21674/0/page/2">this article</a>';
 370                                         print " for instructions.</li>\n";
 371                                         dieout( );
 372                                 }
 373                                 print "OK</li>\n";
 374
 375                                 // Does this user have the rights to the tsearch2 tables?
 376                                 $ctype = pg_fetch_result( $this->doQuery( 'SHOW lc_ctype' ), 0, 0 );
 377                                 print '<li>Checking tsearch2 permissions...';
 378                                 // Let's check all four, just to be safe
 379                                 error_reporting( 0 );
 380                                 $ts2tables = array( 'cfg', 'cfgmap', 'dict', 'parser' );
 381                                 $safetsschema = $this->addIdentifierQuotes( $wgDBts2schema );
 382                                 foreach ( $ts2tables as $tname ) {
 383                                         $SQL = "SELECT count(*) FROM $safetsschema.pg_ts_$tname";
 384                                         $res = $this->doQuery( $SQL );
 385                                         if ( !$res ) {
 386                                                 print "<b>FAILED</b> to access " . htmlspecialchars( "pg_ts_$tname" ) .
 387                                                         ". Make sure that the user \"". htmlspecialchars( $wgDBuser ) .
 388                                                         "\" has SELECT access to all four tsearch2 tables</li>\n";
 389                                                 dieout( );
 390                                         }
 391                                 }
 392                                 $SQL = "SELECT ts_name FROM $safetsschema.pg_ts_cfg WHERE locale = " . $this->addQuotes( $ctype ) ;
 393                                 $SQL .= " ORDER BY CASE WHEN ts_name <> 'default' THEN 1 ELSE 0 END";
 394                                 $res = $this->doQuery( $SQL );
 395                                 error_reporting( E_ALL );
 396                                 if ( !$res ) {
 397                                         print "<b>FAILED</b>. Could not determine the tsearch2 locale information</li>\n";
 398                                         dieout("</ul>");
 399                                 }
 400                                 print 'OK</li>';
 401
 402                                 // Will the current locale work? Can we force it to?
 403                                 print '<li>Verifying tsearch2 locale with ' . htmlspecialchars( $ctype ) . '...';
 404                                 $rows = $this->numRows( $res );
 405                                 $resetlocale = 0;
 406                                 if ( !$rows ) {
 407                                         print "<b>not found</b></li>\n";
 408                                         print '<li>Attempting to set default tsearch2 locale to "' . htmlspecialchars( $ctype ) . '"...';
 409                                         $resetlocale = 1;
 410                                 } else {
 411                                         $tsname = pg_fetch_result( $res, 0, 0 );
 412                                         if ( $tsname != 'default' ) {
 413                                                 print "<b>not set to default (" . htmlspecialchars( $tsname ) . ")</b>";
 414                                                 print "<li>Attempting to change tsearch2 default locale to \"" .
 415                                                         htmlspecialchars( $ctype ) . "\"...";
 416                                                 $resetlocale = 1;
 417                                         }
 418                                 }
 419                                 if ( $resetlocale ) {
 420                                         $SQL = "UPDATE $safetsschema.pg_ts_cfg SET locale = " . $this->addQuotes( $ctype ) . " WHERE ts_name = 'default'";
 421                                         $res = $this->doQuery( $SQL );
 422                                         if ( !$res ) {
 423                                                 print '<b>FAILED</b>. ';
 424                                                 print 'Please make sure that the locale in pg_ts_cfg for "default" is set to "' .
 425                                                         htmlspecialchars( $ctype ) . "\"</li>\n";
 426                                                 dieout( );
 427                                         }
 428                                         print 'OK</li>';
 429                                 }
 430
 431                                 // Final test: try out a simple tsearch2 query
 432                                 $SQL = "SELECT $safetsschema.to_tsvector('default','MediaWiki tsearch2 testing')";
 433                                 $res = $this->doQuery( $SQL );
 434                                 if ( !$res ) {
 435                                         print '<b>FAILED</b>. Specifically, "' . htmlspecialchars( $SQL ) . '" did not work.</li>';
 436                                         dieout( );
 437                                 }
 438                                 print 'OK</li>';
 439                         }
 440
 441                         // Install plpgsql if needed
 442                         $this->setup_plpgsql();
 443
 444                         // Does the schema already exist? Who owns it?
 445                         $result = $this->schemaExists( $wgDBmwschema );
 446                         if ( !$result ) {
 447                                 print '<li>Creating schema <b>' . htmlspecialchars( $wgDBmwschema ) . '</b> ...';
 448                                 error_reporting( 0 );
 449                                 $safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
 450                                 $result = $this->doQuery( "CREATE SCHEMA $safeschema" );
 451                                 error_reporting( E_ALL );
 452                                 if ( !$result ) {
 453                                         print '<b>FAILED</b>. The user "' . htmlspecialchars( $wgDBuser ) .
 454                                                 '" must be able to access the schema. '.
 455                                                 'You can try making them the owner of the database, or try creating the schema with a '.
 456                                                 'different user, and then grant access to the "' .
 457                                                 htmlspecialchars( $wgDBuser ) . "\" user.</li>\n";
 458                                         dieout( );
 459                                 }
 460                                 print "OK</li>\n";
 461                         } elseif ( $result != $wgDBuser ) {
 462                                 print '<li>Schema "' . htmlspecialchars( $wgDBmwschema ) . '" exists but is not owned by "' .
 463                                         htmlspecialchars( $wgDBuser ) . "\". Not ideal.</li>\n";
 464                         } else {
 465                                 print '<li>Schema "' . htmlspecialchars( $wgDBmwschema ) . '" exists and is owned by "' .
 466                                         htmlspecialchars( $wgDBuser ) . "\". Excellent.</li>\n";
 467                         }
 468
 469                         // Always return GMT time to accomodate the existing integer-based timestamp assumption
 470                         print "<li>Setting the timezone to GMT for user \"" . htmlspecialchars( $wgDBuser ) . '" ...';
 471                         $SQL = "ALTER USER $safeuser SET timezone = 'GMT'";
 472                         $result = pg_query( $this->mConn, $SQL );
 473                         if ( !$result ) {
 474                                 print "<b>FAILED</b>.</li>\n";
 475                                 dieout( );
 476                         }
 477                         print "OK</li>\n";
 478                         // Set for the rest of this session
 479                         $SQL = "SET timezone = 'GMT'";
 480                         $result = pg_query( $this->mConn, $SQL );
 481                         if ( !$result ) {
 482                                 print "<li>Failed to set timezone</li>\n";
 483                                 dieout( );
 484                         }
 485
 486                         print '<li>Setting the datestyle to ISO, YMD for user "' . htmlspecialchars( $wgDBuser ) . '" ...';
 487                         $SQL = "ALTER USER $safeuser SET datestyle = 'ISO, YMD'";
 488                         $result = pg_query( $this->mConn, $SQL );
 489                         if ( !$result ) {
 490                                 print "<b>FAILED</b>.</li>\n";
 491                                 dieout( );
 492                         }
 493                         print "OK</li>\n";
 494                         // Set for the rest of this session
 495                         $SQL = "SET datestyle = 'ISO, YMD'";
 496                         $result = pg_query( $this->mConn, $SQL );
 497                         if ( !$result ) {
 498                                 print "<li>Failed to set datestyle</li>\n";
 499                                 dieout( );
 500                         }
 501
 502                         // Fix up the search paths if needed
 503                         print '<li>Setting the search path for user "' . htmlspecialchars( $wgDBuser ) . '" ...';
 504                         $path = $this->addIdentifierQuotes( $wgDBmwschema );
 505                         if ( $wgDBts2schema !== $wgDBmwschema ) {
 506                                 $path .= ', '. $this->addIdentifierQuotes( $wgDBts2schema );
 507                         }
 508                         if ( $wgDBmwschema !== 'public' && $wgDBts2schema !== 'public' ) {
 509                                 $path .= ', public';
 510                         }
 511                         $SQL = "ALTER USER $safeuser SET search_path = $path";
 512                         $result = pg_query( $this->mConn, $SQL );
 513                         if ( !$result ) {
 514                                 print "<b>FAILED</b>.</li>\n";
 515                                 dieout( );
 516                         }
 517                         print "OK</li>\n";
 518                         // Set for the rest of this session
 519                         $SQL = "SET search_path = $path";
 520                         $result = pg_query( $this->mConn, $SQL );
 521                         if ( !$result ) {
 522                                 print "<li>Failed to set search_path</li>\n";
 523                                 dieout( );
 524                         }
 525                         define( 'POSTGRES_SEARCHPATH', $path );
 526                 }
 527         }
 528
 529         /**
 530          * Closes a database connection, if it is open
 531          * Returns success, true if already closed
 532          */
 533         function close() {
 534                 $this->mOpened = false;
 535                 if ( $this->mConn ) {
 536                         return pg_close( $this->mConn );
 537                 } else {
 538                         return true;
 539                 }
 540         }
 541
 542         function doQuery( $sql ) {
 543                 if ( function_exists( 'mb_convert_encoding' ) ) {
 544                         $sql = mb_convert_encoding( $sql, 'UTF-8' );
 545                 }
 546                 $this->mLastResult = pg_query( $this->mConn, $sql );
 547                 $this->mAffectedRows = null; // use pg_affected_rows(mLastResult)
 548                 return $this->mLastResult;
 549         }
 550
 551         function queryIgnore( $sql, $fname = 'DatabasePostgres::queryIgnore' ) {
 552                 return $this->query( $sql, $fname, true );
 553         }
 554
 555         function freeResult( $res ) {
 556                 if ( $res instanceof ResultWrapper ) {
 557                         $res = $res->result;
 558                 }
 559                 if ( !@pg_free_result( $res ) ) {
 560                         throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
 561                 }
 562         }
 563
 564         function fetchObject( $res ) {
 565                 if ( $res instanceof ResultWrapper ) {
 566                         $res = $res->result;
 567                 }
 568                 @$row = pg_fetch_object( $res );
 569                 # FIXME: HACK HACK HACK HACK debug
 570
 571                 # TODO:
 572                 # hashar : not sure if the following test really trigger if the object
 573                 #          fetching failed.
 574                 if( pg_last_error( $this->mConn ) ) {
 575                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 576                 }
 577                 return $row;
 578         }
 579
 580         function fetchRow( $res ) {
 581                 if ( $res instanceof ResultWrapper ) {
 582                         $res = $res->result;
 583                 }
 584                 @$row = pg_fetch_array( $res );
 585                 if( pg_last_error( $this->mConn ) ) {
 586                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 587                 }
 588                 return $row;
 589         }
 590
 591         function numRows( $res ) {
 592                 if ( $res instanceof ResultWrapper ) {
 593                         $res = $res->result;
 594                 }
 595                 @$n = pg_num_rows( $res );
 596                 if( pg_last_error( $this->mConn ) ) {
 597                         throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
 598                 }
 599                 return $n;
 600         }
 601
 602         function numFields( $res ) {
 603                 if ( $res instanceof ResultWrapper ) {
 604                         $res = $res->result;
 605                 }
 606                 return pg_num_fields( $res );
 607         }
 608
 609         function fieldName( $res, $n ) {
 610                 if ( $res instanceof ResultWrapper ) {
 611                         $res = $res->result;
 612                 }
 613                 return pg_field_name( $res, $n );
 614         }
 615
 616         /**
 617          * This must be called after nextSequenceVal
 618          */
 619         function insertId() {
 620                 return $this->mInsertId;
 621         }
 622
 623         function dataSeek( $res, $row ) {
 624                 if ( $res instanceof ResultWrapper ) {
 625                         $res = $res->result;
 626                 }
 627                 return pg_result_seek( $res, $row );
 628         }
 629
 630         function lastError() {
 631                 if ( $this->mConn ) {
 632                         return pg_last_error();
 633                 } else {
 634                         return 'No database connection';
 635                 }
 636         }
 637         function lastErrno() {
 638                 return pg_last_error() ? 1 : 0;
 639         }
 640
 641         function affectedRows() {
 642                 if ( !is_null( $this->mAffectedRows ) ) {
 643                         // Forced result for simulated queries
 644                         return $this->mAffectedRows;
 645                 }
 646                 if( empty( $this->mLastResult ) ) {
 647                         return 0;
 648                 }
 649                 return pg_affected_rows( $this->mLastResult );
 650         }
 651
 652         /**
 653          * Estimate rows in dataset
 654          * Returns estimated count, based on EXPLAIN output
 655          * This is not necessarily an accurate estimate, so use sparingly
 656          * Returns -1 if count cannot be found
 657          * Takes same arguments as Database::select()
 658          */
 659         function estimateRowCount( $table, $vars = '*', $conds='', $fname = 'DatabasePostgres::estimateRowCount', $options = array() ) {
 660                 $options['EXPLAIN'] = true;
 661                 $res = $this->select( $table, $vars, $conds, $fname, $options );
 662                 $rows = -1;
 663                 if ( $res ) {
 664                         $row = $this->fetchRow( $res );
 665                         $count = array();
 666                         if( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
 667                                 $rows = $count[1];
 668                         }
 669                 }
 670                 return $rows;
 671         }
 672
 673         /**
 674          * Returns information about an index
 675          * If errors are explicitly ignored, returns NULL on failure
 676          */
 677         function indexInfo( $table, $index, $fname = 'DatabasePostgres::indexInfo' ) {
 678                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
 679                 $res = $this->query( $sql, $fname );
 680                 if ( !$res ) {
 681                         return null;
 682                 }
 683                 foreach ( $res as $row ) {
 684                         if ( $row->indexname == $this->indexName( $index ) ) {
 685                                 return $row;
 686                         }
 687                 }
 688                 return false;
 689         }
 690
 691         function indexUnique( $table, $index, $fname = 'DatabasePostgres::indexUnique' ) {
 692                 $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'".
 693                         " AND indexdef LIKE 'CREATE UNIQUE%(" .
 694                         $this->strencode( $this->indexName( $index ) ) .
 695                         ")'";
 696                 $res = $this->query( $sql, $fname );
 697                 if ( !$res ) {
 698                         return null;
 699                 }
 700                 foreach ( $res as $row ) {
 701                         return true;
 702                 }
 703                 return false;
 704         }
 705
 706         /**
 707          * INSERT wrapper, inserts an array into a table
 708          *
 709          * $args may be a single associative array, or an array of these with numeric keys,
 710          * for multi-row insert (Postgres version 8.2 and above only).
 711          *
 712          * @param $table   String: Name of the table to insert to.
 713          * @param $args    Array: Items to insert into the table.
 714          * @param $fname   String: Name of the function, for profiling
 715          * @param $options String or Array. Valid options: IGNORE
 716          *
 717          * @return bool Success of insert operation. IGNORE always returns true.
 718          */
 719         function insert( $table, $args, $fname = 'DatabasePostgres::insert', $options = array() ) {
 720                 if ( !count( $args ) ) {
 721                         return true;
 722                 }
 723
 724                 $table = $this->tableName( $table );
 725                 if (! isset( $this->numeric_version ) ) {
 726                         $this->getServerVersion();
 727                 }
 728
 729                 if ( !is_array( $options ) ) {
 730                         $options = array( $options );
 731                 }
 732
 733                 if ( isset( $args[0] ) && is_array( $args[0] ) ) {
 734                         $multi = true;
 735                         $keys = array_keys( $args[0] );
 736                 } else {
 737                         $multi = false;
 738                         $keys = array_keys( $args );
 739                 }
 740
 741                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 742                 $ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';
 743
 744                 // If we are not in a transaction, we need to be for savepoint trickery
 745                 $didbegin = 0;
 746                 if ( $ignore ) {
 747                         if ( !$this->mTrxLevel ) {
 748                                 $this->begin();
 749                                 $didbegin = 1;
 750                         }
 751                         $olde = error_reporting( 0 );
 752                         // For future use, we may want to track the number of actual inserts
 753                         // Right now, insert (all writes) simply return true/false
 754                         $numrowsinserted = 0;
 755                 }
 756
 757                 $sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';
 758
 759                 if ( $multi ) {
 760                         if ( $this->numeric_version >= 8.2 && !$ignore ) {
 761                                 $first = true;
 762                                 foreach ( $args as $row ) {
 763                                         if ( $first ) {
 764                                                 $first = false;
 765                                         } else {
 766                                                 $sql .= ',';
 767                                         }
 768                                         $sql .= '(' . $this->makeList( $row ) . ')';
 769                                 }
 770                                 $res = (bool)$this->query( $sql, $fname, $ignore );
 771                         } else {
 772                                 $res = true;
 773                                 $origsql = $sql;
 774                                 foreach ( $args as $row ) {
 775                                         $tempsql = $origsql;
 776                                         $tempsql .= '(' . $this->makeList( $row ) . ')';
 777
 778                                         if ( $ignore ) {
 779                                                 pg_query( $this->mConn, "SAVEPOINT $ignore" );
 780                                         }
 781
 782                                         $tempres = (bool)$this->query( $tempsql, $fname, $ignore );
 783
 784                                         if ( $ignore ) {
 785                                                 $bar = pg_last_error();
 786                                                 if ( $bar != false ) {
 787                                                         pg_query( $this->mConn, "ROLLBACK TO $ignore" );
 788                                                 } else {
 789                                                         pg_query( $this->mConn, "RELEASE $ignore" );
 790                                                         $numrowsinserted++;
 791                                                 }
 792                                         }
 793
 794                                         // If any of them fail, we fail overall for this function call
 795                                         // Note that this will be ignored if IGNORE is set
 796                                         if ( !$tempres ) {
 797                                                 $res = false;
 798                                         }
 799                                 }
 800                         }
 801                 } else {
 802                         // Not multi, just a lone insert
 803                         if ( $ignore ) {
 804                                 pg_query($this->mConn, "SAVEPOINT $ignore");
 805                         }
 806
 807                         $sql .= '(' . $this->makeList( $args ) . ')';
 808                         $res = (bool)$this->query( $sql, $fname, $ignore );
 809                         if ( $ignore ) {
 810                                 $bar = pg_last_error();
 811                                 if ( $bar != false ) {
 812                                         pg_query( $this->mConn, "ROLLBACK TO $ignore" );
 813                                 } else {
 814                                         pg_query( $this->mConn, "RELEASE $ignore" );
 815                                         $numrowsinserted++;
 816                                 }
 817                         }
 818                 }
 819                 if ( $ignore ) {
 820                         $olde = error_reporting( $olde );
 821                         if ( $didbegin ) {
 822                                 $this->commit();
 823                         }
 824
 825                         // Set the affected row count for the whole operation
 826                         $this->mAffectedRows = $numrowsinserted;
 827
 828                         // IGNORE always returns true
 829                         return true;
 830                 }
 831
 832                 return $res;
 833         }
 834
 835         /**
 836          * INSERT SELECT wrapper
 837          * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
 838          * Source items may be literals rather then field names, but strings should be quoted with Database::addQuotes()
 839          * $conds may be "*" to copy the whole table
 840          * srcTable may be an array of tables.
 841          * @todo FIXME: implement this a little better (seperate select/insert)?
 842          */
 843         function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabasePostgres::insertSelect',
 844                 $insertOptions = array(), $selectOptions = array() )
 845         {
 846                 $destTable = $this->tableName( $destTable );
 847
 848                 // If IGNORE is set, we use savepoints to emulate mysql's behavior
 849                 $ignore = in_array( 'IGNORE', $insertOptions ) ? 'mw' : '';
 850
 851                 if( is_array( $insertOptions ) ) {
 852                         $insertOptions = implode( ' ', $insertOptions );
 853                 }
 854                 if( !is_array( $selectOptions ) ) {
 855                         $selectOptions = array( $selectOptions );
 856                 }
 857                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
 858                 if( is_array( $srcTable ) ) {
 859                         $srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
 860                 } else {
 861                         $srcTable = $this->tableName( $srcTable );
 862                 }
 863
 864                 // If we are not in a transaction, we need to be for savepoint trickery
 865                 $didbegin = 0;
 866                 if ( $ignore ) {
 867                         if( !$this->mTrxLevel ) {
 868                                 $this->begin();
 869                                 $didbegin = 1;
 870                         }
 871                         $olde = error_reporting( 0 );
 872                         $numrowsinserted = 0;
 873                         pg_query( $this->mConn, "SAVEPOINT $ignore");
 874                 }
 875
 876                 $sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
 877                                 " SELECT $startOpts " . implode( ',', $varMap ) .
 878                                 " FROM $srcTable $useIndex";
 879
 880                 if ( $conds != '*' ) {
 881                         $sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
 882                 }
 883
 884                 $sql .= " $tailOpts";
 885
 886                 $res = (bool)$this->query( $sql, $fname, $ignore );
 887                 if( $ignore ) {
 888                         $bar = pg_last_error();
 889                         if( $bar != false ) {
 890                                 pg_query( $this->mConn, "ROLLBACK TO $ignore" );
 891                         } else {
 892                                 pg_query( $this->mConn, "RELEASE $ignore" );
 893                                 $numrowsinserted++;
 894                         }
 895                         $olde = error_reporting( $olde );
 896                         if( $didbegin ) {
 897                                 $this->commit();
 898                         }
 899
 900                         // Set the affected row count for the whole operation
 901                         $this->mAffectedRows = $numrowsinserted;
 902
 903                         // IGNORE always returns true
 904                         return true;
 905                 }
 906
 907                 return $res;
 908         }
 909
 910         function tableName( $name ) {
 911                 # Replace reserved words with better ones
 912                 switch( $name ) {
 913                         case 'user':
 914                                 return 'mwuser';
 915                         case 'text':
 916                                 return 'pagecontent';
 917                         default:
 918                                 return $name;
 919                 }
 920         }
 921
 922         /**
 923          * Return the next in a sequence, save the value for retrieval via insertId()
 924          */
 925         function nextSequenceValue( $seqName ) {
 926                 $safeseq = str_replace( "'", "''", $seqName );
 927                 $res = $this->query( "SELECT nextval('$safeseq')" );
 928                 $row = $this->fetchRow( $res );
 929                 $this->mInsertId = $row[0];
 930                 return $this->mInsertId;
 931         }
 932
 933         /**
 934          * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
 935          */
 936         function currentSequenceValue( $seqName ) {
 937                 $safeseq = str_replace( "'", "''", $seqName );
 938                 $res = $this->query( "SELECT currval('$safeseq')" );
 939                 $row = $this->fetchRow( $res );
 940                 $currval = $row[0];
 941                 return $currval;
 942         }
 943
 944         /**
 945          * REPLACE query wrapper
 946          * Postgres simulates this with a DELETE followed by INSERT
 947          * $row is the row to insert, an associative array
 948          * $uniqueIndexes is an array of indexes. Each element may be either a
 949          * field name or an array of field names
 950          *
 951          * It may be more efficient to leave off unique indexes which are unlikely to collide.
 952          * However if you do this, you run the risk of encountering errors which wouldn't have
 953          * occurred in MySQL
 954          */
 955         function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabasePostgres::replace' ) {
 956                 $table = $this->tableName( $table );
 957
 958                 if ( count( $rows ) == 0 ) {
 959                         return;
 960                 }
 961
 962                 # Single row case
 963                 if ( !is_array( reset( $rows ) ) ) {
 964                         $rows = array( $rows );
 965                 }
 966
 967                 foreach( $rows as $row ) {
 968                         # Delete rows which collide
 969                         if ( $uniqueIndexes ) {
 970                                 $sql = "DELETE FROM $table WHERE ";
 971                                 $first = true;
 972                                 foreach ( $uniqueIndexes as $index ) {
 973                                         if ( $first ) {
 974                                                 $first = false;
 975                                                 $sql .= '(';
 976                                         } else {
 977                                                 $sql .= ') OR (';
 978                                         }
 979                                         if ( is_array( $index ) ) {
 980                                                 $first2 = true;
 981                                                 foreach ( $index as $col ) {
 982                                                         if ( $first2 ) {
 983                                                                 $first2 = false;
 984                                                         } else {
 985                                                                 $sql .= ' AND ';
 986                                                         }
 987                                                         $sql .= $col.'=' . $this->addQuotes( $row[$col] );
 988                                                 }
 989                                         } else {
 990                                                 $sql .= $index.'=' . $this->addQuotes( $row[$index] );
 991                                         }
 992                                 }
 993                                 $sql .= ')';
 994                                 $this->query( $sql, $fname );
 995                         }
 996
 997                         # Now insert the row
 998                         $sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
 999                                 $this->makeList( $row, LIST_COMMA ) . ')';
1000                         $this->query( $sql, $fname );
1001                 }
1002         }
1003
1004         # DELETE where the condition is a join
1005         function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'DatabasePostgres::deleteJoin' ) {
1006                 if ( !$conds ) {
1007                         throw new DBUnexpectedError( $this, 'DatabasePostgres::deleteJoin() called with empty $conds' );
1008                 }
1009
1010                 $delTable = $this->tableName( $delTable );
1011                 $joinTable = $this->tableName( $joinTable );
1012                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
1013                 if ( $conds != '*' ) {
1014                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
1015                 }
1016                 $sql .= ')';
1017
1018                 $this->query( $sql, $fname );
1019         }
1020
1021         # Returns the size of a text field, or -1 for "unlimited"
1022         function textFieldSize( $table, $field ) {
1023                 $table = $this->tableName( $table );
1024                 $sql = "SELECT t.typname as ftype,a.atttypmod as size
1025                         FROM pg_class c, pg_attribute a, pg_type t
1026                         WHERE relname='$table' AND a.attrelid=c.oid AND
1027                                 a.atttypid=t.oid and a.attname='$field'";
1028                 $res =$this->query( $sql );
1029                 $row = $this->fetchObject( $res );
1030                 if ( $row->ftype == 'varchar' ) {
1031                         $size = $row->size - 4;
1032                 } else {
1033                         $size = $row->size;
1034                 }
1035                 return $size;
1036         }
1037
1038         function limitResult( $sql, $limit, $offset = false ) {
1039                 return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
1040         }
1041
1042         function wasDeadlock() {
1043                 return $this->lastErrno() == '40P01';
1044         }
1045
1046         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabasePostgres::duplicateTableStructure' ) {
1047                 return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName (LIKE $oldName INCLUDING DEFAULTS)", $fname );
1048         }
1049
1050         function timestamp( $ts = 0 ) {
1051                 return wfTimestamp( TS_POSTGRES, $ts );
1052         }
1053
1054         /**
1055          * Return aggregated value function call
1056          */
1057         function aggregateValue( $valuedata, $valuename = 'value' ) {
1058                 return $valuedata;
1059         }
1060
1061         function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
1062                 // Ignore errors during error handling to avoid infinite recursion
1063                 $ignore = $this->ignoreErrors( true );
1064                 $this->mErrorCount++;
1065
1066                 if ( $ignore || $tempIgnore ) {
1067                         wfDebug( "SQL ERROR (ignored): $error\n" );
1068                         $this->ignoreErrors( $ignore );
1069                 } else {
1070                         $message = "A database error has occurred.  Did you forget to run maintenance/update.php after upgrading?  See: http://www.mediawiki.org/wiki/Manual:Upgrading#Run_the_update_script\n" .
1071                                 "Query: $sql\n" .
1072                                 "Function: $fname\n" .
1073                                 "Error: $errno $error\n";
1074                         throw new DBUnexpectedError( $this, $message );
1075                 }
1076         }
1077
1078         /**
1079          * @return string wikitext of a link to the server software's web site
1080          */
1081         public static function getSoftwareLink() {
1082                 return '[http://www.postgresql.org/ PostgreSQL]';
1083         }
1084
1085         /**
1086          * @return string Version information from the database
1087          */
1088         function getServerVersion() {
1089                 if ( !isset( $this->numeric_version ) ) {
1090                         $versionInfo = pg_version( $this->mConn );
1091                         if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
1092                                 // Old client, abort install
1093                                 $this->numeric_version = '7.3 or earlier';
1094                         } elseif ( isset( $versionInfo['server'] ) ) {
1095                                 // Normal client
1096                                 $this->numeric_version = $versionInfo['server'];
1097                         } else {
1098                                 // Bug 16937: broken pgsql extension from PHP<5.3
1099                                 $this->numeric_version = pg_parameter_status( $this->mConn, 'server_version' );
1100                         }
1101                 }
1102                 return $this->numeric_version;
1103         }
1104
1105         /**
1106          * Query whether a given relation exists (in the given schema, or the
1107          * default mw one if not given)
1108          */
1109         function relationExists( $table, $types, $schema = false ) {
1110                 global $wgDBmwschema;
1111                 if ( !is_array( $types ) ) {
1112                         $types = array( $types );
1113                 }
1114                 if ( !$schema ) {
1115                         $schema = $wgDBmwschema;
1116                 }
1117                 $etable = $this->addQuotes( $table );
1118                 $eschema = $this->addQuotes( $schema );
1119                 $SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
1120                         . "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
1121                         . "AND c.relkind IN ('" . implode( "','", $types ) . "')";
1122                 $res = $this->query( $SQL );
1123                 $count = $res ? $res->numRows() : 0;
1124                 return (bool)$count;
1125         }
1126
1127         /**
1128          * For backward compatibility, this function checks both tables and
1129          * views.
1130          */
1131         function tableExists( $table, $schema = false ) {
1132                 return $this->relationExists( $table, array( 'r', 'v' ), $schema );
1133         }
1134
1135         function sequenceExists( $sequence, $schema = false ) {
1136                 return $this->relationExists( $sequence, 'S', $schema );
1137         }
1138
1139         function triggerExists( $table, $trigger ) {
1140                 global $wgDBmwschema;
1141
1142                 $q = <<<SQL
1143         SELECT 1 FROM pg_class, pg_namespace, pg_trigger
1144                 WHERE relnamespace=pg_namespace.oid AND relkind='r'
1145                       AND tgrelid=pg_class.oid
1146                       AND nspname=%s AND relname=%s AND tgname=%s
1147 SQL;
1148                 $res = $this->query(
1149                         sprintf(
1150                                 $q,
1151                                 $this->addQuotes( $wgDBmwschema ),
1152                                 $this->addQuotes( $table ),
1153                                 $this->addQuotes( $trigger )
1154                         )
1155                 );
1156                 if ( !$res ) {
1157                         return null;
1158                 }
1159                 $rows = $res->numRows();
1160                 return $rows;
1161         }
1162
1163         function ruleExists( $table, $rule ) {
1164                 global $wgDBmwschema;
1165                 $exists = $this->selectField( 'pg_rules', 'rulename',
1166                         array(
1167                                 'rulename' => $rule,
1168                                 'tablename' => $table,
1169                                 'schemaname' => $wgDBmwschema
1170                         )
1171                 );
1172                 return $exists === $rule;
1173         }
1174
1175         function constraintExists( $table, $constraint ) {
1176                 global $wgDBmwschema;
1177                 $SQL = sprintf( "SELECT 1 FROM information_schema.table_constraints ".
1178                            "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
1179                         $this->addQuotes( $wgDBmwschema ),
1180                         $this->addQuotes( $table ),
1181                         $this->addQuotes( $constraint )
1182                 );
1183                 $res = $this->query( $SQL );
1184                 if ( !$res ) {
1185                         return null;
1186                 }
1187                 $rows = $res->numRows();
1188                 return $rows;
1189         }
1190
1191         /**
1192          * Query whether a given schema exists. Returns the name of the owner
1193          */
1194         function schemaExists( $schema ) {
1195                 $eschema = str_replace( "'", "''", $schema );
1196                 $SQL = "SELECT rolname FROM pg_catalog.pg_namespace n, pg_catalog.pg_roles r "
1197                                 ."WHERE n.nspowner=r.oid AND n.nspname = '$eschema'";
1198                 $res = $this->query( $SQL );
1199                 if ( $res && $res->numRows() ) {
1200                         $row = $res->fetchObject();
1201                         $owner = $row->rolname;
1202                 } else {
1203                         $owner = false;
1204                 }
1205                 return $owner;
1206         }
1207
1208         function fieldInfo( $table, $field ) {
1209                 return PostgresField::fromText( $this, $table, $field );
1210         }
1211
1212         /**
1213          * pg_field_type() wrapper
1214          */
1215         function fieldType( $res, $index ) {
1216                 if ( $res instanceof ResultWrapper ) {
1217                         $res = $res->result;
1218                 }
1219                 return pg_field_type( $res, $index );
1220         }
1221
1222         /* Not even sure why this is used in the main codebase... */
1223         function limitResultForUpdate( $sql, $num ) {
1224                 return $sql;
1225         }
1226
1227         function encodeBlob( $b ) {
1228                 return new Blob( pg_escape_bytea( $this->mConn, $b ) );
1229         }
1230
1231         function decodeBlob( $b ) {
1232                 if ( $b instanceof Blob ) {
1233                         $b = $b->fetch();
1234                 }
1235                 return pg_unescape_bytea( $b );
1236         }
1237
1238         function strencode( $s ) { # Should not be called by us
1239                 return pg_escape_string( $this->mConn, $s );
1240         }
1241
1242         function addQuotes( $s ) {
1243                 if ( is_null( $s ) ) {
1244                         return 'NULL';
1245                 } elseif ( is_bool( $s ) ) {
1246                         return intval( $s );
1247                 } elseif ( $s instanceof Blob ) {
1248                         return "'" . $s->fetch( $s ) . "'";
1249                 }
1250                 return "'" . pg_escape_string( $this->mConn, $s ) . "'";
1251         }
1252
1253         /**
1254          * Postgres specific version of replaceVars.
1255          * Calls the parent version in Database.php
1256          *
1257          * @private
1258          *
1259          * @param $ins String: SQL string, read from a stream (usually tables.sql)
1260          *
1261          * @return string SQL string
1262          */
1263         protected function replaceVars( $ins ) {
1264                 $ins = parent::replaceVars( $ins );
1265
1266                 if ( $this->numeric_version >= 8.3 ) {
1267                         // Thanks for not providing backwards-compatibility, 8.3
1268                         $ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
1269                 }
1270
1271                 if ( $this->numeric_version <= 8.1 ) { // Our minimum version
1272                         $ins = str_replace( 'USING gin', 'USING gist', $ins );
1273                 }
1274
1275                 return $ins;
1276         }
1277
1278         /**
1279          * Various select options
1280          *
1281          * @private
1282          *
1283          * @param $options Array: an associative array of options to be turned into
1284          *              an SQL query, valid keys are listed in the function.
1285          * @return array
1286          */
1287         function makeSelectOptions( $options ) {
1288                 $preLimitTail = $postLimitTail = '';
1289                 $startOpts = $useIndex = '';
1290
1291                 $noKeyOptions = array();
1292                 foreach ( $options as $key => $option ) {
1293                         if ( is_numeric( $key ) ) {
1294                                 $noKeyOptions[$option] = true;
1295                         }
1296                 }
1297
1298                 if ( isset( $options['GROUP BY'] ) ) {
1299                         $preLimitTail .= ' GROUP BY ' . $options['GROUP BY'];
1300                 }
1301                 if ( isset( $options['HAVING'] ) ) {
1302                         $preLimitTail .= " HAVING {$options['HAVING']}";
1303                 }
1304                 if ( isset( $options['ORDER BY'] ) ) {
1305                         $preLimitTail .= ' ORDER BY ' . $options['ORDER BY'];
1306                 }
1307
1308                 //if ( isset( $options['LIMIT'] ) ) {
1309                 //      $tailOpts .= $this->limitResult( '', $options['LIMIT'],
1310                 //              isset( $options['OFFSET'] ) ? $options['OFFSET']
1311                 //              : false );
1312                 //}
1313
1314                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1315                         $postLimitTail .= ' FOR UPDATE';
1316                 }
1317                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
1318                         $postLimitTail .= ' LOCK IN SHARE MODE';
1319                 }
1320                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1321                         $startOpts .= 'DISTINCT';
1322                 }
1323
1324                 return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
1325         }
1326
1327         function setFakeMaster( $enabled = true ) {}
1328
1329         function getDBname() {
1330                 return $this->mDBname;
1331         }
1332
1333         function getServer() {
1334                 return $this->mServer;
1335         }
1336
1337         function buildConcat( $stringList ) {
1338                 return implode( ' || ', $stringList );
1339         }
1340
1341         public function getSearchEngine() {
1342                 return 'SearchPostgres';
1343         }
1344 } // end DatabasePostgres class