<?php
/**
 * This is the Postgres database abstraction layer.
 *
 * @file
 * @ingroup Database
 */

class PostgresField implements Field {
	private $name, $tablename, $type, $nullable, $max_length, $deferred, $deferrable, $conname;

	static function fromText($db, $table, $field) {
	global $wgDBmwschema;

		$q = <<<SQL
SELECT
 attnotnull, attlen, COALESCE(conname, '') AS conname,
 COALESCE(condeferred, 'f') AS deferred,
 COALESCE(condeferrable, 'f') AS deferrable,
 CASE WHEN typname = 'int2' THEN 'smallint'
  WHEN typname = 'int4' THEN 'integer'
  WHEN typname = 'int8' THEN 'bigint'
  WHEN typname = 'bpchar' THEN 'char'
 ELSE typname END AS typname
FROM pg_class c
JOIN pg_namespace n ON (n.oid = c.relnamespace)
JOIN pg_attribute a ON (a.attrelid = c.oid)
JOIN pg_type t ON (t.oid = a.atttypid)
LEFT JOIN pg_constraint o ON (o.conrelid = c.oid AND a.attnum = ANY(o.conkey) AND o.contype = 'f')
WHERE relkind = 'r'
AND nspname=%s
AND relname=%s
AND attname=%s;
SQL;

		$table = $db->tableName( $table );
		$res = $db->query(
			sprintf( $q,
				$db->addQuotes( $wgDBmwschema ),
				$db->addQuotes( $table ),
				$db->addQuotes( $field )
			)
		);
		$row = $db->fetchObject( $res );
		if ( !$row ) {
			return null;
		}
		$n = new PostgresField;
		$n->type = $row->typname;
		$n->nullable = ( $row->attnotnull == 'f' );
		$n->name = $field;
		$n->tablename = $table;
		$n->max_length = $row->attlen;
		$n->deferrable = ( $row->deferrable == 't' );
		$n->deferred = ( $row->deferred == 't' );
		$n->conname = $row->conname;
		return $n;
	}

	function name() {
		return $this->name;
	}

	function tableName() {
		return $this->tablename;
	}

	function type() {
		return $this->type;
	}

	function isNullable() {
		return $this->nullable;
	}

	function maxLength() {
		return $this->max_length;
	}

	function is_deferrable() {
		return $this->deferrable;
	}

	function is_deferred() {
		return $this->deferred;
	}

	function conname() {
		return $this->conname;
	}

}

/**
 * @ingroup Database
 */
class DatabasePostgres extends DatabaseBase {
	var $mInsertId = null;
	var $mLastResult = null;
	var $numeric_version = null;
	var $mAffectedRows = null;

	function __construct( $server = false, $user = false, $password = false, $dbName = false,
		$flags = 0 )
	{
		$this->mFlags = $flags;
		$this->open( $server, $user, $password, $dbName );
	}

	function getType() {
		return 'postgres';
	}

	function cascadingDeletes() {
		return true;
	}
	function cleanupTriggers() {
		return true;
	}
	function strictIPs() {
		return true;
	}
	function realTimestamps() {
		return true;
	}
	function implicitGroupby() {
		return false;
	}
	function implicitOrderby() {
		return false;
	}
	function searchableIPs() {
		return true;
	}
	function functionalIndexes() {
		return true;
	}

	function hasConstraint( $name ) {
		global $wgDBmwschema;
		$SQL = "SELECT 1 FROM pg_catalog.pg_constraint c, pg_catalog.pg_namespace n WHERE c.connamespace = n.oid AND conname = '" .
				pg_escape_string( $this->mConn, $name ) . "' AND n.nspname = '" . pg_escape_string( $this->mConn, $wgDBmwschema ) ."'";
		$res = $this->doQuery( $SQL );
		return $this->numRows( $res );
	}

	static function newFromParams( $server, $user, $password, $dbName, $flags = 0 ) {
		return new DatabasePostgres( $server, $user, $password, $dbName, $flags );
	}

	/**
	 * Usually aborts on failure
	 */
	function open( $server, $user, $password, $dbName ) {
		# Test for Postgres support, to avoid suppressed fatal error
		if ( !function_exists( 'pg_connect' ) ) {
			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" );
		}

		global $wgDBport;

		if ( !strlen( $user ) ) { # e.g. the class is being loaded
			return;
		}
		$this->close();
		$this->mServer = $server;
		$this->mPort = $port = $wgDBport;
		$this->mUser = $user;
		$this->mPassword = $password;
		$this->mDBname = $dbName;

		$connectVars = array(
			'dbname' => $dbName,
			'user' => $user,
			'password' => $password
		);
		if ( $server != false && $server != '' ) {
			$connectVars['host'] = $server;
		}
		if ( $port != false && $port != '' ) {
			$connectVars['port'] = $port;
		}
		$connectString = $this->makeConnectionString( $connectVars, PGSQL_CONNECT_FORCE_NEW );

		$this->installErrorHandler();
		$this->mConn = pg_connect( $connectString );
		$phpError = $this->restoreErrorHandler();

		if ( !$this->mConn ) {
			wfDebug( "DB connection error\n" );
			wfDebug( "Server: $server, Database: $dbName, User: $user, Password: " . substr( $password, 0, 3 ) . "...\n" );
			wfDebug( $this->lastError() . "\n" );
			throw new DBConnectionError( $this, $phpError );
		}

		$this->mOpened = true;

		global $wgCommandLineMode;
		# If called from the command-line (e.g. importDump), only show errors
		if ( $wgCommandLineMode ) {
			$this->doQuery( "SET client_min_messages = 'ERROR'" );
		}

		$this->doQuery( "SET client_encoding='UTF8'" );

		global $wgDBmwschema, $wgDBts2schema;
		if ( isset( $wgDBmwschema ) && isset( $wgDBts2schema )
			&& $wgDBmwschema !== 'mediawiki'
			&& preg_match( '/^\w+$/', $wgDBmwschema )
			&& preg_match( '/^\w+$/', $wgDBts2schema )
		) {
			$safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
			$this->doQuery( "SET search_path = $safeschema, $wgDBts2schema, public" );
		}

		return $this->mConn;
	}

	function makeConnectionString( $vars ) {
		$s = '';
		foreach ( $vars as $name => $value ) {
			$s .= "$name='" . str_replace( "'", "\\'", $value ) . "' ";
		}
		return $s;
	}


	function initial_setup( $superuser, $password, $dbName ) {
		// If this is the initial connection, setup the schema stuff and possibly create the user
		global $wgDBname, $wgDBuser, $wgDBpassword, $wgDBmwschema, $wgDBts2schema;

		$safeuser = $this->addIdentifierQuotes( $wgDBuser );
		// Are we connecting as a superuser for the first time?
		if ( $superuser ) {
			// Are we really a superuser? Check out our rights
			$SQL = "SELECT
                      CASE WHEN usesuper IS TRUE THEN
                      CASE WHEN usecreatedb IS TRUE THEN 3 ELSE 1 END
                      ELSE CASE WHEN usecreatedb IS TRUE THEN 2 ELSE 0 END
                    END AS rights
                    FROM pg_catalog.pg_user WHERE usename = " . $this->addQuotes( $superuser );
			$rows = $this->numRows( $res = $this->doQuery( $SQL ) );
			if ( !$rows ) {
				print '<li>ERROR: Could not read permissions for user "' . htmlspecialchars( $superuser ) . "\"</li>\n";
				dieout( );
			}
			$perms = pg_fetch_result( $res, 0, 0 );

			$SQL = "SELECT 1 FROM pg_catalog.pg_user WHERE usename = " . $this->addQuotes( $wgDBuser );
			$rows = $this->numRows( $this->doQuery( $SQL ) );
			if ( $rows ) {
				print '<li>User "' . htmlspecialchars( $wgDBuser ) . '" already exists, skipping account creation.</li>';
			} else {
				if ( $perms != 1 && $perms != 3 ) {
					print '<li>ERROR: the user "' . htmlspecialchars( $superuser ) . '" cannot create other users. ';
					print 'Please use a different Postgres user.</li>';
					dieout( );
				}
				print '<li>Creating user <b>' . htmlspecialchars( $wgDBuser ) . '</b>...';
				$safepass = $this->addQuotes( $wgDBpassword );
				$SQL = "CREATE USER $safeuser NOCREATEDB PASSWORD $safepass";
				$this->doQuery( $SQL );
				print "OK</li>\n";
			}
			// User now exists, check out the database
			if ( $dbName != $wgDBname ) {
				$SQL = "SELECT 1 FROM pg_catalog.pg_database WHERE datname = " . $this->addQuotes( $wgDBname );
				$rows = $this->numRows( $this->doQuery( $SQL ) );
				if ( $rows ) {
					print '<li>Database "' . htmlspecialchars( $wgDBname ) . '" already exists, skipping database creation.</li>';
				} else {
					if ( $perms < 1 ) {
						print '<li>ERROR: the user "' . htmlspecialchars( $superuser ) . '" cannot create databases. ';
						print 'Please use a different Postgres user.</li>';
						dieout( );
					}
					print '<li>Creating database <b>' . htmlspecialchars( $wgDBname ) . '</b>...';
					$safename = $this->addIdentifierQuotes( $wgDBname );
					$SQL = "CREATE DATABASE $safename OWNER $safeuser ";
					$this->doQuery( $SQL );
					print "OK</li>\n";
					// Hopefully tsearch2 and plpgsql are in template1...
				}

				// Reconnect to check out tsearch2 rights for this user
				print '<li>Connecting to "' . htmlspecialchars( $wgDBname ) . '" as superuser "' .
					htmlspecialchars( $superuser ) . '" to check rights...';

				$connectVars = array();
				if ( $this->mServer != false && $this->mServer != '' ) {
					$connectVars['host'] = $this->mServer;
				}
				if ( $this->mPort != false && $this->mPort != '' ) {
					$connectVars['port'] = $this->mPort;
				}
				$connectVars['dbname'] = $wgDBname;
				$connectVars['user'] = $superuser;
				$connectVars['password'] = $password;

				@$this->mConn = pg_connect( $this->makeConnectionString( $connectVars ) );
				if ( !$this->mConn ) {
					print "<b>FAILED TO CONNECT!</b></li>";
					dieout( );
				}
				print "OK</li>\n";
			}

			if ( $this->numeric_version < 8.3 ) {
				// Tsearch2 checks
				print '<li>Checking that tsearch2 is installed in the database "' .
					htmlspecialchars( $wgDBname ) . '"...';
				if ( !$this->tableExists( 'pg_ts_cfg', $wgDBts2schema ) ) {
					print '<b>FAILED</b>. tsearch2 must be installed in the database "' .
						htmlspecialchars( $wgDBname ) . '".';
					print 'Please see <a href="http://www.devx.com/opensource/Article/21674/0/page/2">this article</a>';
					print " for instructions or ask on #postgresql on irc.freenode.net</li>\n";
					dieout( );
				}
				print "OK</li>\n";
				print '<li>Ensuring that user "' . htmlspecialchars( $wgDBuser ) .
					'" has select rights on the tsearch2 tables...';
				foreach ( array( 'cfg', 'cfgmap', 'dict', 'parser' ) as $table ) {
					$SQL = "GRANT SELECT ON pg_ts_$table TO $safeuser";
					$this->doQuery( $SQL );
				}
				print "OK</li>\n";
			}

			// Setup the schema for this user if needed
			$result = $this->schemaExists( $wgDBmwschema );
			$safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
			if ( !$result ) {
				print '<li>Creating schema <b>' . htmlspecialchars( $wgDBmwschema ) . '</b> ...';
				$result = $this->doQuery( "CREATE SCHEMA $safeschema AUTHORIZATION $safeuser" );
				if ( !$result ) {
					print "<b>FAILED</b>.</li>\n";
					dieout( );
				}
				print "OK</li>\n";
			} else {
				print "<li>Schema already exists, explicitly granting rights...\n";
				$safeschema2 = $this->addQuotes( $wgDBmwschema );
				$SQL = "SELECT 'GRANT ALL ON '||pg_catalog.quote_ident(relname)||' TO $safeuser;'\n".
					"FROM pg_catalog.pg_class p, pg_catalog.pg_namespace n\n".
					"WHERE relnamespace = n.oid AND n.nspname = $safeschema2\n".
					"AND p.relkind IN ('r','S','v')\n";
				$SQL .= "UNION\n";
				$SQL .= "SELECT 'GRANT ALL ON FUNCTION '||pg_catalog.quote_ident(proname)||'('||\n".
					"pg_catalog.oidvectortypes(p.proargtypes)||') TO $safeuser;'\n".
					"FROM pg_catalog.pg_proc p, pg_catalog.pg_namespace n\n".
					"WHERE p.pronamespace = n.oid AND n.nspname = $safeschema2";
				$res = $this->doQuery( $SQL );
				if ( !$res ) {
					print "<b>FAILED</b>. Could not set rights for the user.</li>\n";
					dieout( );
				}
				$this->doQuery( "SET search_path = $safeschema" );
				$rows = $this->numRows( $res );
				while ( $rows ) {
					$rows--;
					$this->doQuery( pg_fetch_result( $res, $rows, 0 ) );
				}
				print "OK</li>";
			}

			// Install plpgsql if needed
			$this->setup_plpgsql();

			return true; // Reconnect as regular user

		} // end superuser

		if ( !defined( 'POSTGRES_SEARCHPATH' ) ) {

			if ( $this->numeric_version < 8.3 ) {
				// Do we have the basic tsearch2 table?
				print '<li>Checking for tsearch2 in the schema "' . htmlspecialchars( $wgDBts2schema ) . '"...';
				if ( !$this->tableExists( 'pg_ts_dict', $wgDBts2schema ) ) {
					print '<b>FAILED</b>. Make sure tsearch2 is installed. See <a href="';
					print 'http://www.devx.com/opensource/Article/21674/0/page/2">this article</a>';
					print " for instructions.</li>\n";
					dieout( );
				}
				print "OK</li>\n";

				// Does this user have the rights to the tsearch2 tables?
				$ctype = pg_fetch_result( $this->doQuery( 'SHOW lc_ctype' ), 0, 0 );
				print '<li>Checking tsearch2 permissions...';
				// Let's check all four, just to be safe
				error_reporting( 0 );
				$ts2tables = array( 'cfg', 'cfgmap', 'dict', 'parser' );
				$safetsschema = $this->addIdentifierQuotes( $wgDBts2schema );
				foreach ( $ts2tables as $tname ) {
					$SQL = "SELECT count(*) FROM $safetsschema.pg_ts_$tname";
					$res = $this->doQuery( $SQL );
					if ( !$res ) {
						print "<b>FAILED</b> to access " . htmlspecialchars( "pg_ts_$tname" ) .
							". Make sure that the user \"". htmlspecialchars( $wgDBuser ) .
							"\" has SELECT access to all four tsearch2 tables</li>\n";
						dieout( );
					}
				}
				$SQL = "SELECT ts_name FROM $safetsschema.pg_ts_cfg WHERE locale = " . $this->addQuotes( $ctype ) ;
				$SQL .= " ORDER BY CASE WHEN ts_name <> 'default' THEN 1 ELSE 0 END";
				$res = $this->doQuery( $SQL );
				error_reporting( E_ALL );
				if ( !$res ) {
					print "<b>FAILED</b>. Could not determine the tsearch2 locale information</li>\n";
					dieout("</ul>");
				}
				print 'OK</li>';

				// Will the current locale work? Can we force it to?
				print '<li>Verifying tsearch2 locale with ' . htmlspecialchars( $ctype ) . '...';
				$rows = $this->numRows( $res );
				$resetlocale = 0;
				if ( !$rows ) {
					print "<b>not found</b></li>\n";
					print '<li>Attempting to set default tsearch2 locale to "' . htmlspecialchars( $ctype ) . '"...';
					$resetlocale = 1;
				} else {
					$tsname = pg_fetch_result( $res, 0, 0 );
					if ( $tsname != 'default' ) {
						print "<b>not set to default (" . htmlspecialchars( $tsname ) . ")</b>";
						print "<li>Attempting to change tsearch2 default locale to \"" .
							htmlspecialchars( $ctype ) . "\"...";
						$resetlocale = 1;
					}
				}
				if ( $resetlocale ) {
					$SQL = "UPDATE $safetsschema.pg_ts_cfg SET locale = " . $this->addQuotes( $ctype ) . " WHERE ts_name = 'default'";
					$res = $this->doQuery( $SQL );
					if ( !$res ) {
						print '<b>FAILED</b>. ';
						print 'Please make sure that the locale in pg_ts_cfg for "default" is set to "' .
							htmlspecialchars( $ctype ) . "\"</li>\n";
						dieout( );
					}
					print 'OK</li>';
				}

				// Final test: try out a simple tsearch2 query
				$SQL = "SELECT $safetsschema.to_tsvector('default','MediaWiki tsearch2 testing')";
				$res = $this->doQuery( $SQL );
				if ( !$res ) {
					print '<b>FAILED</b>. Specifically, "' . htmlspecialchars( $SQL ) . '" did not work.</li>';
					dieout( );
				}
				print 'OK</li>';
			}

			// Install plpgsql if needed
			$this->setup_plpgsql();

			// Does the schema already exist? Who owns it?
			$result = $this->schemaExists( $wgDBmwschema );
			if ( !$result ) {
				print '<li>Creating schema <b>' . htmlspecialchars( $wgDBmwschema ) . '</b> ...';
				error_reporting( 0 );
				$safeschema = $this->addIdentifierQuotes( $wgDBmwschema );
				$result = $this->doQuery( "CREATE SCHEMA $safeschema" );
				error_reporting( E_ALL );
				if ( !$result ) {
					print '<b>FAILED</b>. The user "' . htmlspecialchars( $wgDBuser ) .
						'" must be able to access the schema. '.
						'You can try making them the owner of the database, or try creating the schema with a '.
						'different user, and then grant access to the "' .
						htmlspecialchars( $wgDBuser ) . "\" user.</li>\n";
					dieout( );
				}
				print "OK</li>\n";
			} elseif ( $result != $wgDBuser ) {
				print '<li>Schema "' . htmlspecialchars( $wgDBmwschema ) . '" exists but is not owned by "' .
					htmlspecialchars( $wgDBuser ) . "\". Not ideal.</li>\n";
			} else {
				print '<li>Schema "' . htmlspecialchars( $wgDBmwschema ) . '" exists and is owned by "' .
					htmlspecialchars( $wgDBuser ) . "\". Excellent.</li>\n";
			}

			// Always return GMT time to accomodate the existing integer-based timestamp assumption
			print "<li>Setting the timezone to GMT for user \"" . htmlspecialchars( $wgDBuser ) . '" ...';
			$SQL = "ALTER USER $safeuser SET timezone = 'GMT'";
			$result = pg_query( $this->mConn, $SQL );
			if ( !$result ) {
				print "<b>FAILED</b>.</li>\n";
				dieout( );
			}
			print "OK</li>\n";
			// Set for the rest of this session
			$SQL = "SET timezone = 'GMT'";
			$result = pg_query( $this->mConn, $SQL );
			if ( !$result ) {
				print "<li>Failed to set timezone</li>\n";
				dieout( );
			}

			print '<li>Setting the datestyle to ISO, YMD for user "' . htmlspecialchars( $wgDBuser ) . '" ...';
			$SQL = "ALTER USER $safeuser SET datestyle = 'ISO, YMD'";
			$result = pg_query( $this->mConn, $SQL );
			if ( !$result ) {
				print "<b>FAILED</b>.</li>\n";
				dieout( );
			}
			print "OK</li>\n";
			// Set for the rest of this session
			$SQL = "SET datestyle = 'ISO, YMD'";
			$result = pg_query( $this->mConn, $SQL );
			if ( !$result ) {
				print "<li>Failed to set datestyle</li>\n";
				dieout( );
			}

			// Fix up the search paths if needed
			print '<li>Setting the search path for user "' . htmlspecialchars( $wgDBuser ) . '" ...';
			$path = $this->addIdentifierQuotes( $wgDBmwschema );
			if ( $wgDBts2schema !== $wgDBmwschema ) {
				$path .= ', '. $this->addIdentifierQuotes( $wgDBts2schema );
			}
			if ( $wgDBmwschema !== 'public' && $wgDBts2schema !== 'public' ) {
				$path .= ', public';
			}
			$SQL = "ALTER USER $safeuser SET search_path = $path";
			$result = pg_query( $this->mConn, $SQL );
			if ( !$result ) {
				print "<b>FAILED</b>.</li>\n";
				dieout( );
			}
			print "OK</li>\n";
			// Set for the rest of this session
			$SQL = "SET search_path = $path";
			$result = pg_query( $this->mConn, $SQL );
			if ( !$result ) {
				print "<li>Failed to set search_path</li>\n";
				dieout( );
			}
			define( 'POSTGRES_SEARCHPATH', $path );
		}
	}

	/**
	 * Closes a database connection, if it is open
	 * Returns success, true if already closed
	 */
	function close() {
		$this->mOpened = false;
		if ( $this->mConn ) {
			return pg_close( $this->mConn );
		} else {
			return true;
		}
	}

	function doQuery( $sql ) {
		if ( function_exists( 'mb_convert_encoding' ) ) {
			$sql = mb_convert_encoding( $sql, 'UTF-8' );
		}
		$this->mLastResult = pg_query( $this->mConn, $sql );
		$this->mAffectedRows = null; // use pg_affected_rows(mLastResult)
		return $this->mLastResult;
	}

	function queryIgnore( $sql, $fname = 'DatabasePostgres::queryIgnore' ) {
		return $this->query( $sql, $fname, true );
	}

	function freeResult( $res ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		if ( !@pg_free_result( $res ) ) {
			throw new DBUnexpectedError( $this, "Unable to free Postgres result\n" );
		}
	}

	function fetchObject( $res ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		@$row = pg_fetch_object( $res );
		# FIXME: HACK HACK HACK HACK debug

		# TODO:
		# hashar : not sure if the following test really trigger if the object
		#          fetching failed.
		if( pg_last_error( $this->mConn ) ) {
			throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
		}
		return $row;
	}

	function fetchRow( $res ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		@$row = pg_fetch_array( $res );
		if( pg_last_error( $this->mConn ) ) {
			throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
		}
		return $row;
	}

	function numRows( $res ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		@$n = pg_num_rows( $res );
		if( pg_last_error( $this->mConn ) ) {
			throw new DBUnexpectedError( $this, 'SQL error: ' . htmlspecialchars( pg_last_error( $this->mConn ) ) );
		}
		return $n;
	}

	function numFields( $res ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		return pg_num_fields( $res );
	}

	function fieldName( $res, $n ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		return pg_field_name( $res, $n );
	}

	/**
	 * This must be called after nextSequenceVal
	 */
	function insertId() {
		return $this->mInsertId;
	}

	function dataSeek( $res, $row ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		return pg_result_seek( $res, $row );
	}

	function lastError() {
		if ( $this->mConn ) {
			return pg_last_error();
		} else {
			return 'No database connection';
		}
	}
	function lastErrno() {
		return pg_last_error() ? 1 : 0;
	}

	function affectedRows() {
		if ( !is_null( $this->mAffectedRows ) ) {
			// Forced result for simulated queries
			return $this->mAffectedRows;
		}
		if( empty( $this->mLastResult ) ) {
			return 0;
		}
		return pg_affected_rows( $this->mLastResult );
	}

	/**
	 * Estimate rows in dataset
	 * Returns estimated count, based on EXPLAIN output
	 * This is not necessarily an accurate estimate, so use sparingly
	 * Returns -1 if count cannot be found
	 * Takes same arguments as Database::select()
	 */
	function estimateRowCount( $table, $vars = '*', $conds='', $fname = 'DatabasePostgres::estimateRowCount', $options = array() ) {
		$options['EXPLAIN'] = true;
		$res = $this->select( $table, $vars, $conds, $fname, $options );
		$rows = -1;
		if ( $res ) {
			$row = $this->fetchRow( $res );
			$count = array();
			if( preg_match( '/rows=(\d+)/', $row[0], $count ) ) {
				$rows = $count[1];
			}
		}
		return $rows;
	}

	/**
	 * Returns information about an index
	 * If errors are explicitly ignored, returns NULL on failure
	 */
	function indexInfo( $table, $index, $fname = 'DatabasePostgres::indexInfo' ) {
		$sql = "SELECT indexname FROM pg_indexes WHERE tablename='$table'";
		$res = $this->query( $sql, $fname );
		if ( !$res ) {
			return null;
		}
		foreach ( $res as $row ) {
			if ( $row->indexname == $this->indexName( $index ) ) {
				return $row;
			}
		}
		return false;
	}

	function indexUnique( $table, $index, $fname = 'DatabasePostgres::indexUnique' ) {
		$sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'".
			" AND indexdef LIKE 'CREATE UNIQUE%(" .
			$this->strencode( $this->indexName( $index ) ) .
			")'";
		$res = $this->query( $sql, $fname );
		if ( !$res ) {
			return null;
		}
		foreach ( $res as $row ) {
			return true;
		}
		return false;
	}

	/**
	 * INSERT wrapper, inserts an array into a table
	 *
	 * $args may be a single associative array, or an array of these with numeric keys,
	 * for multi-row insert (Postgres version 8.2 and above only).
	 *
	 * @param $table   String: Name of the table to insert to.
	 * @param $args    Array: Items to insert into the table.
	 * @param $fname   String: Name of the function, for profiling
	 * @param $options String or Array. Valid options: IGNORE
	 *
	 * @return bool Success of insert operation. IGNORE always returns true.
	 */
	function insert( $table, $args, $fname = 'DatabasePostgres::insert', $options = array() ) {
		if ( !count( $args ) ) {
			return true;
		}

		$table = $this->tableName( $table );
		if (! isset( $this->numeric_version ) ) {
			$this->getServerVersion();
		}

		if ( !is_array( $options ) ) {
			$options = array( $options );
		}

		if ( isset( $args[0] ) && is_array( $args[0] ) ) {
			$multi = true;
			$keys = array_keys( $args[0] );
		} else {
			$multi = false;
			$keys = array_keys( $args );
		}

		// If IGNORE is set, we use savepoints to emulate mysql's behavior
		$ignore = in_array( 'IGNORE', $options ) ? 'mw' : '';

		// If we are not in a transaction, we need to be for savepoint trickery
		$didbegin = 0;
		if ( $ignore ) {
			if ( !$this->mTrxLevel ) {
				$this->begin();
				$didbegin = 1;
			}
			$olde = error_reporting( 0 );
			// For future use, we may want to track the number of actual inserts
			// Right now, insert (all writes) simply return true/false
			$numrowsinserted = 0;
		}

		$sql = "INSERT INTO $table (" . implode( ',', $keys ) . ') VALUES ';

		if ( $multi ) {
			if ( $this->numeric_version >= 8.2 && !$ignore ) {
				$first = true;
				foreach ( $args as $row ) {
					if ( $first ) {
						$first = false;
					} else {
						$sql .= ',';
					}
					$sql .= '(' . $this->makeList( $row ) . ')';
				}
				$res = (bool)$this->query( $sql, $fname, $ignore );
			} else {
				$res = true;
				$origsql = $sql;
				foreach ( $args as $row ) {
					$tempsql = $origsql;
					$tempsql .= '(' . $this->makeList( $row ) . ')';

					if ( $ignore ) {
						pg_query( $this->mConn, "SAVEPOINT $ignore" );
					}

					$tempres = (bool)$this->query( $tempsql, $fname, $ignore );

					if ( $ignore ) {
						$bar = pg_last_error();
						if ( $bar != false ) {
							pg_query( $this->mConn, "ROLLBACK TO $ignore" );
						} else {
							pg_query( $this->mConn, "RELEASE $ignore" );
							$numrowsinserted++;
						}
					}

					// If any of them fail, we fail overall for this function call
					// Note that this will be ignored if IGNORE is set
					if ( !$tempres ) {
						$res = false;
					}
				}
			}
		} else {
			// Not multi, just a lone insert
			if ( $ignore ) {
				pg_query($this->mConn, "SAVEPOINT $ignore");
			}

			$sql .= '(' . $this->makeList( $args ) . ')';
			$res = (bool)$this->query( $sql, $fname, $ignore );
			if ( $ignore ) {
				$bar = pg_last_error();
				if ( $bar != false ) {
					pg_query( $this->mConn, "ROLLBACK TO $ignore" );
				} else {
					pg_query( $this->mConn, "RELEASE $ignore" );
					$numrowsinserted++;
				}
			}
		}
		if ( $ignore ) {
			$olde = error_reporting( $olde );
			if ( $didbegin ) {
				$this->commit();
			}

			// Set the affected row count for the whole operation
			$this->mAffectedRows = $numrowsinserted;

			// IGNORE always returns true
			return true;
		}

		return $res;
	}

	/**
	 * INSERT SELECT wrapper
	 * $varMap must be an associative array of the form array( 'dest1' => 'source1', ...)
	 * Source items may be literals rather then field names, but strings should be quoted with Database::addQuotes()
	 * $conds may be "*" to copy the whole table
	 * srcTable may be an array of tables.
	 * @todo FIXME: implement this a little better (seperate select/insert)?
	 */
	function insertSelect( $destTable, $srcTable, $varMap, $conds, $fname = 'DatabasePostgres::insertSelect',
		$insertOptions = array(), $selectOptions = array() )
	{
		$destTable = $this->tableName( $destTable );

		// If IGNORE is set, we use savepoints to emulate mysql's behavior
		$ignore = in_array( 'IGNORE', $insertOptions ) ? 'mw' : '';

		if( is_array( $insertOptions ) ) {
			$insertOptions = implode( ' ', $insertOptions );
		}
		if( !is_array( $selectOptions ) ) {
			$selectOptions = array( $selectOptions );
		}
		list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
		if( is_array( $srcTable ) ) {
			$srcTable = implode( ',', array_map( array( &$this, 'tableName' ), $srcTable ) );
		} else {
			$srcTable = $this->tableName( $srcTable );
		}

		// If we are not in a transaction, we need to be for savepoint trickery
		$didbegin = 0;
		if ( $ignore ) {
			if( !$this->mTrxLevel ) {
				$this->begin();
				$didbegin = 1;
			}
			$olde = error_reporting( 0 );
			$numrowsinserted = 0;
			pg_query( $this->mConn, "SAVEPOINT $ignore");
		}

		$sql = "INSERT INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
				" SELECT $startOpts " . implode( ',', $varMap ) .
				" FROM $srcTable $useIndex";

		if ( $conds != '*' ) {
			$sql .= ' WHERE ' . $this->makeList( $conds, LIST_AND );
		}

		$sql .= " $tailOpts";

		$res = (bool)$this->query( $sql, $fname, $ignore );
		if( $ignore ) {
			$bar = pg_last_error();
			if( $bar != false ) {
				pg_query( $this->mConn, "ROLLBACK TO $ignore" );
			} else {
				pg_query( $this->mConn, "RELEASE $ignore" );
				$numrowsinserted++;
			}
			$olde = error_reporting( $olde );
			if( $didbegin ) {
				$this->commit();
			}

			// Set the affected row count for the whole operation
			$this->mAffectedRows = $numrowsinserted;

			// IGNORE always returns true
			return true;
		}

		return $res;
	}

	function tableName( $name ) {
		# Replace reserved words with better ones
		switch( $name ) {
			case 'user':
				return 'mwuser';
			case 'text':
				return 'pagecontent';
			default:
				return $name;
		}
	}

	/**
	 * Return the next in a sequence, save the value for retrieval via insertId()
	 */
	function nextSequenceValue( $seqName ) {
		$safeseq = str_replace( "'", "''", $seqName );
		$res = $this->query( "SELECT nextval('$safeseq')" );
		$row = $this->fetchRow( $res );
		$this->mInsertId = $row[0];
		return $this->mInsertId;
	}

	/**
	 * Return the current value of a sequence. Assumes it has been nextval'ed in this session.
	 */
	function currentSequenceValue( $seqName ) {
		$safeseq = str_replace( "'", "''", $seqName );
		$res = $this->query( "SELECT currval('$safeseq')" );
		$row = $this->fetchRow( $res );
		$currval = $row[0];
		return $currval;
	}

	/**
	 * REPLACE query wrapper
	 * Postgres simulates this with a DELETE followed by INSERT
	 * $row is the row to insert, an associative array
	 * $uniqueIndexes is an array of indexes. Each element may be either a
	 * field name or an array of field names
	 *
	 * It may be more efficient to leave off unique indexes which are unlikely to collide.
	 * However if you do this, you run the risk of encountering errors which wouldn't have
	 * occurred in MySQL
	 */
	function replace( $table, $uniqueIndexes, $rows, $fname = 'DatabasePostgres::replace' ) {
		$table = $this->tableName( $table );

		if ( count( $rows ) == 0 ) {
			return;
		}

		# Single row case
		if ( !is_array( reset( $rows ) ) ) {
			$rows = array( $rows );
		}

		foreach( $rows as $row ) {
			# Delete rows which collide
			if ( $uniqueIndexes ) {
				$sql = "DELETE FROM $table WHERE ";
				$first = true;
				foreach ( $uniqueIndexes as $index ) {
					if ( $first ) {
						$first = false;
						$sql .= '(';
					} else {
						$sql .= ') OR (';
					}
					if ( is_array( $index ) ) {
						$first2 = true;
						foreach ( $index as $col ) {
							if ( $first2 ) {
								$first2 = false;
							} else {
								$sql .= ' AND ';
							}
							$sql .= $col.'=' . $this->addQuotes( $row[$col] );
						}
					} else {
						$sql .= $index.'=' . $this->addQuotes( $row[$index] );
					}
				}
				$sql .= ')';
				$this->query( $sql, $fname );
			}

			# Now insert the row
			$sql = "INSERT INTO $table (" . $this->makeList( array_keys( $row ), LIST_NAMES ) .') VALUES (' .
				$this->makeList( $row, LIST_COMMA ) . ')';
			$this->query( $sql, $fname );
		}
	}

	# DELETE where the condition is a join
	function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds, $fname = 'DatabasePostgres::deleteJoin' ) {
		if ( !$conds ) {
			throw new DBUnexpectedError( $this, 'DatabasePostgres::deleteJoin() called with empty $conds' );
		}

		$delTable = $this->tableName( $delTable );
		$joinTable = $this->tableName( $joinTable );
		$sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
		if ( $conds != '*' ) {
			$sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
		}
		$sql .= ')';

		$this->query( $sql, $fname );
	}

	# Returns the size of a text field, or -1 for "unlimited"
	function textFieldSize( $table, $field ) {
		$table = $this->tableName( $table );
		$sql = "SELECT t.typname as ftype,a.atttypmod as size
			FROM pg_class c, pg_attribute a, pg_type t
			WHERE relname='$table' AND a.attrelid=c.oid AND
				a.atttypid=t.oid and a.attname='$field'";
		$res =$this->query( $sql );
		$row = $this->fetchObject( $res );
		if ( $row->ftype == 'varchar' ) {
			$size = $row->size - 4;
		} else {
			$size = $row->size;
		}
		return $size;
	}

	function limitResult( $sql, $limit, $offset = false ) {
		return "$sql LIMIT $limit " . ( is_numeric( $offset ) ? " OFFSET {$offset} " : '' );
	}

	function wasDeadlock() {
		return $this->lastErrno() == '40P01';
	}

	function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = 'DatabasePostgres::duplicateTableStructure' ) {
		return $this->query( 'CREATE ' . ( $temporary ? 'TEMPORARY ' : '' ) . " TABLE $newName (LIKE $oldName INCLUDING DEFAULTS)", $fname );
	}

	function timestamp( $ts = 0 ) {
		return wfTimestamp( TS_POSTGRES, $ts );
	}

	/**
	 * Return aggregated value function call
	 */
	function aggregateValue( $valuedata, $valuename = 'value' ) {
		return $valuedata;
	}

	function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
		// Ignore errors during error handling to avoid infinite recursion
		$ignore = $this->ignoreErrors( true );
		$this->mErrorCount++;

		if ( $ignore || $tempIgnore ) {
			wfDebug( "SQL ERROR (ignored): $error\n" );
			$this->ignoreErrors( $ignore );
		} else {
			$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" .
				"Query: $sql\n" .
				"Function: $fname\n" .
				"Error: $errno $error\n";
			throw new DBUnexpectedError( $this, $message );
		}
	}

	/**
	 * @return string wikitext of a link to the server software's web site
	 */
	public static function getSoftwareLink() {
		return '[http://www.postgresql.org/ PostgreSQL]';
	}

	/**
	 * @return string Version information from the database
	 */
	function getServerVersion() {
		if ( !isset( $this->numeric_version ) ) {
			$versionInfo = pg_version( $this->mConn );
			if ( version_compare( $versionInfo['client'], '7.4.0', 'lt' ) ) {
				// Old client, abort install
				$this->numeric_version = '7.3 or earlier';
			} elseif ( isset( $versionInfo['server'] ) ) {
				// Normal client
				$this->numeric_version = $versionInfo['server'];
			} else {
				// Bug 16937: broken pgsql extension from PHP<5.3
				$this->numeric_version = pg_parameter_status( $this->mConn, 'server_version' );
			}
		}
		return $this->numeric_version;
	}

	/**
	 * Query whether a given relation exists (in the given schema, or the
	 * default mw one if not given)
	 */
	function relationExists( $table, $types, $schema = false ) {
		global $wgDBmwschema;
		if ( !is_array( $types ) ) {
			$types = array( $types );
		}
		if ( !$schema ) {
			$schema = $wgDBmwschema;
		}
		$etable = $this->addQuotes( $table );
		$eschema = $this->addQuotes( $schema );
		$SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n "
			. "WHERE c.relnamespace = n.oid AND c.relname = $etable AND n.nspname = $eschema "
			. "AND c.relkind IN ('" . implode( "','", $types ) . "')";
		$res = $this->query( $SQL );
		$count = $res ? $res->numRows() : 0;
		return (bool)$count;
	}

	/**
	 * For backward compatibility, this function checks both tables and
	 * views.
	 */
	function tableExists( $table, $schema = false ) {
		return $this->relationExists( $table, array( 'r', 'v' ), $schema );
	}

	function sequenceExists( $sequence, $schema = false ) {
		return $this->relationExists( $sequence, 'S', $schema );
	}

	function triggerExists( $table, $trigger ) {
		global $wgDBmwschema;

		$q = <<<SQL
	SELECT 1 FROM pg_class, pg_namespace, pg_trigger
		WHERE relnamespace=pg_namespace.oid AND relkind='r'
		      AND tgrelid=pg_class.oid
		      AND nspname=%s AND relname=%s AND tgname=%s
SQL;
		$res = $this->query(
			sprintf(
				$q,
				$this->addQuotes( $wgDBmwschema ),
				$this->addQuotes( $table ),
				$this->addQuotes( $trigger )
			)
		);
		if ( !$res ) {
			return null;
		}
		$rows = $res->numRows();
		return $rows;
	}

	function ruleExists( $table, $rule ) {
		global $wgDBmwschema;
		$exists = $this->selectField( 'pg_rules', 'rulename',
			array(
				'rulename' => $rule,
				'tablename' => $table,
				'schemaname' => $wgDBmwschema
			)
		);
		return $exists === $rule;
	}

	function constraintExists( $table, $constraint ) {
		global $wgDBmwschema;
		$SQL = sprintf( "SELECT 1 FROM information_schema.table_constraints ".
			   "WHERE constraint_schema = %s AND table_name = %s AND constraint_name = %s",
			$this->addQuotes( $wgDBmwschema ),
			$this->addQuotes( $table ),
			$this->addQuotes( $constraint )
		);
		$res = $this->query( $SQL );
		if ( !$res ) {
			return null;
		}
		$rows = $res->numRows();
		return $rows;
	}

	/**
	 * Query whether a given schema exists. Returns the name of the owner
	 */
	function schemaExists( $schema ) {
		$eschema = str_replace( "'", "''", $schema );
		$SQL = "SELECT rolname FROM pg_catalog.pg_namespace n, pg_catalog.pg_roles r "
				."WHERE n.nspowner=r.oid AND n.nspname = '$eschema'";
		$res = $this->query( $SQL );
		if ( $res && $res->numRows() ) {
			$row = $res->fetchObject();
			$owner = $row->rolname;
		} else {
			$owner = false;
		}
		return $owner;
	}

	function fieldInfo( $table, $field ) {
		return PostgresField::fromText( $this, $table, $field );
	}

	/**
	 * pg_field_type() wrapper
	 */
	function fieldType( $res, $index ) {
		if ( $res instanceof ResultWrapper ) {
			$res = $res->result;
		}
		return pg_field_type( $res, $index );
	}

	/* Not even sure why this is used in the main codebase... */
	function limitResultForUpdate( $sql, $num ) {
		return $sql;
	}

	function encodeBlob( $b ) {
		return new Blob( pg_escape_bytea( $this->mConn, $b ) );
	}

	function decodeBlob( $b ) {
		if ( $b instanceof Blob ) {
			$b = $b->fetch();
		}
		return pg_unescape_bytea( $b );
	}

	function strencode( $s ) { # Should not be called by us
		return pg_escape_string( $this->mConn, $s );
	}

	function addQuotes( $s ) {
		if ( is_null( $s ) ) {
			return 'NULL';
		} elseif ( is_bool( $s ) ) {
			return intval( $s );
		} elseif ( $s instanceof Blob ) {
			return "'" . $s->fetch( $s ) . "'";
		}
		return "'" . pg_escape_string( $this->mConn, $s ) . "'";
	}

	/**
	 * Postgres specific version of replaceVars.
	 * Calls the parent version in Database.php
	 *
	 * @private
	 *
	 * @param $ins String: SQL string, read from a stream (usually tables.sql)
	 *
	 * @return string SQL string
	 */
	protected function replaceVars( $ins ) {
		$ins = parent::replaceVars( $ins );

		if ( $this->numeric_version >= 8.3 ) {
			// Thanks for not providing backwards-compatibility, 8.3
			$ins = preg_replace( "/to_tsvector\s*\(\s*'default'\s*,/", 'to_tsvector(', $ins );
		}

		if ( $this->numeric_version <= 8.1 ) { // Our minimum version
			$ins = str_replace( 'USING gin', 'USING gist', $ins );
		}

		return $ins;
	}

	/**
	 * Various select options
	 *
	 * @private
	 *
	 * @param $options Array: an associative array of options to be turned into
	 *              an SQL query, valid keys are listed in the function.
	 * @return array
	 */
	function makeSelectOptions( $options ) {
		$preLimitTail = $postLimitTail = '';
		$startOpts = $useIndex = '';

		$noKeyOptions = array();
		foreach ( $options as $key => $option ) {
			if ( is_numeric( $key ) ) {
				$noKeyOptions[$option] = true;
			}
		}

		if ( isset( $options['GROUP BY'] ) ) {
			$preLimitTail .= ' GROUP BY ' . $options['GROUP BY'];
		}
		if ( isset( $options['HAVING'] ) ) {
			$preLimitTail .= " HAVING {$options['HAVING']}";
		}
		if ( isset( $options['ORDER BY'] ) ) {
			$preLimitTail .= ' ORDER BY ' . $options['ORDER BY'];
		}

		//if ( isset( $options['LIMIT'] ) ) {
		//	$tailOpts .= $this->limitResult( '', $options['LIMIT'],
		//		isset( $options['OFFSET'] ) ? $options['OFFSET']
		//		: false );
		//}

		if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
			$postLimitTail .= ' FOR UPDATE';
		}
		if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
			$postLimitTail .= ' LOCK IN SHARE MODE';
		}
		if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
			$startOpts .= 'DISTINCT';
		}

		return array( $startOpts, $useIndex, $preLimitTail, $postLimitTail );
	}

	function setFakeMaster( $enabled = true ) {}

	function getDBname() {
		return $this->mDBname;
	}

	function getServer() {
		return $this->mServer;
	}

	function buildConcat( $stringList ) {
		return implode( ' || ', $stringList );
	}

	public function getSearchEngine() {
		return 'SearchPostgres';
	}
} // end DatabasePostgres class