(bug 10323) Special:Undelete should have "inverse selection" button

[mediawiki.git] / includes / db / DatabasePostgres.php

<?php
/**
 * @ingroup Database
 * @file
 * This is the Postgres database abstraction layer.
 *
 */
class PostgresField {
        private $name, $tablename, $type, $nullable, $max_length;

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

                $q = <<<END
SELECT
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,
attnotnull, attlen
FROM pg_class, pg_namespace, pg_attribute, pg_type
WHERE relnamespace=pg_namespace.oid
AND relkind='r'
AND attrelid=pg_class.oid
AND atttypid=pg_type.oid
AND nspname=%s
AND relname=%s
AND attname=%s;
END;
                $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;
                return $n;
        }

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

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

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

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

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

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

        function DatabasePostgres($server = false, $user = false, $password = false, $dbName = false,
                $failFunction = false, $flags = 0 )
        {

                global $wgOut;
                # Can't get a reference if it hasn't been set yet
                if ( !isset( $wgOut ) ) {
                        $wgOut = NULL;
                }
                $this->mOut =& $wgOut;
                $this->mFailFunction = $failFunction;
                $this->mFlags = $flags;
                $this->open( $server, $user, $password, $dbName);

        }

        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( $name ) . "' AND n.nspname = '" . pg_escape_string($wgDBmwschema) ."'";
                return $this->numRows($res = $this->doQuery($SQL));
        }

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

        /**
         * Usually aborts on failure
         * If the failFunction is set to a non-zero integer, returns success
         */
        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;

                $hstring="";
                if ($server!=false && $server!="") {
                        $hstring="host=$server ";
                }
                if ($port!=false && $port!="") {
                        $hstring .= "port=$port ";
                }

                error_reporting( E_ALL );
                @$this->mConn = pg_connect("$hstring dbname=$dbName user=$user password=$password");

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

                $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'");
                }

                global $wgDBmwschema, $wgDBts2schema;
                if (isset( $wgDBmwschema ) && isset( $wgDBts2schema )
                        && $wgDBmwschema !== 'mediawiki'
                        && preg_match( '/^\w+$/', $wgDBmwschema )
                        && preg_match( '/^\w+$/', $wgDBts2schema )
                ) {
                        $safeschema = $this->quote_ident($wgDBmwschema);
                        $safeschema2 = $this->quote_ident($wgDBts2schema);
                        $this->doQuery("SET search_path = $safeschema, $wgDBts2schema, public");
                }

                return $this->mConn;
        }


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

                print "<li>Checking the version of Postgres...";
                $version = $this->getServerVersion();
                $PGMINVER = '8.1';
                if ($this->numeric_version < $PGMINVER) {
                        print "<b>FAILED</b>. Required version is $PGMINVER. You have $this->numeric_version ($version)</li>\n";
                        dieout("</ul>");
                }
                print "version $this->numeric_version is OK.</li>\n";

                $safeuser = $this->quote_ident($wgDBuser);
                // Are we connecting as a superuser for the first time?
                if ($wgDBsuperuser) {
                        // 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 = " . $this->addQuotes($wgDBsuperuser);
                        $rows = $this->numRows($res = $this->doQuery($SQL));
                        if (!$rows) {
                                print "<li>ERROR: Could not read permissions for user \"$wgDBsuperuser\"</li>\n";
                                dieout('</ul>');
                        }
                        $perms = pg_fetch_result($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 \"$wgDBuser\" already exists, skipping account creation.</li>";
                        }
                        else {
                                if ($perms != 1 and $perms != 3) {
                                        print "<li>ERROR: the user \"$wgDBsuperuser\" cannot create other users. ";
                                        print 'Please use a different Postgres user.</li>';
                                        dieout('</ul>');
                                }
                                print "<li>Creating user <b>$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 \"$wgDBname\" already exists, skipping database creation.</li>";
                                }
                                else {
                                        if ($perms < 2) {
                                                print "<li>ERROR: the user \"$wgDBsuperuser\" cannot create databases. ";
                                                print 'Please use a different Postgres user.</li>';
                                                dieout('</ul>');
                                        }
                                        print "<li>Creating database <b>$wgDBname</b>...";
                                        $safename = $this->quote_ident($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 \"$wgDBname\" as superuser \"$wgDBsuperuser\" to check rights...";

                                $hstring="";
                                if ($this->mServer!=false && $this->mServer!="") {
                                        $hstring="host=$this->mServer ";
                                }
                                if ($this->mPort!=false && $this->mPort!="") {
                                        $hstring .= "port=$this->mPort ";
                                }

                                @$this->mConn = pg_connect("$hstring dbname=$wgDBname user=$wgDBsuperuser password=$password");
                                if ( $this->mConn == false ) {
                                        print "<b>FAILED TO CONNECT!</b></li>";
                                        dieout("</ul>");
                                }
                                print "OK</li>\n";
                        }

                        if ($this->numeric_version < 8.3) {
                                // Tsearch2 checks
                                print "<li>Checking that tsearch2 is installed in the database \"$wgDBname\"...";
                                if (! $this->tableExists("pg_ts_cfg", $wgDBts2schema)) {
                                        print "<b>FAILED</b>. tsearch2 must be installed in the database \"$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("</ul>");
                                }
                                print "OK</li>\n";
                                print "<li>Ensuring that user \"$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 = $this->quote_ident($wgDBmwschema);
                        if (!$result) {
                                print "<li>Creating schema <b>$wgDBmwschema</b> ...";
                                $result = $this->doQuery("CREATE SCHEMA $safeschema AUTHORIZATION $safeuser");
                                if (!$result) {
                                        print "<b>FAILED</b>.</li>\n";
                                        dieout("</ul>");
                                }
                                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("</ul>");
                                }
                                $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();

                        $wgDBsuperuser = '';
                        return true; // Reconnect as regular user

                } // end superuser

                if (!defined('POSTGRES_SEARCHPATH')) {

                        if ($this->numeric_version < 8.3) {
                                // Do we have the basic tsearch2 table?
                                print "<li>Checking for tsearch2 in the schema \"$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("</ul>");
                                }
                                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 = $this->quote_ident($wgDBts2schema);
                                foreach ( $ts2tables AS $tname ) {
                                        $SQL = "SELECT count(*) FROM $safetsschema.pg_ts_$tname";
                                        $res = $this->doQuery($SQL);
                                        if (!$res) {
                                                print "<b>FAILED</b> to access pg_ts_$tname. Make sure that the user ".
                                                        "\"$wgDBuser\" has SELECT access to all four tsearch2 tables</li>\n";
                                                dieout("</ul>");
                                        }
                                }
                                $SQL = "SELECT ts_name FROM $safetsschema.pg_ts_cfg WHERE locale = '$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 $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 \"$ctype\"...";
                                        $resetlocale = 1;
                                }
                                else {
                                        $tsname = pg_fetch_result($res, 0, 0);
                                        if ($tsname != 'default') {
                                                print "<b>not set to default ($tsname)</b>";
                                                print "<li>Attempting to change tsearch2 default locale to \"$ctype\"...";
                                                $resetlocale = 1;
                                        }
                                }
                                if ($resetlocale) {
                                        $SQL = "UPDATE $safetsschema.pg_ts_cfg SET locale = '$ctype' WHERE ts_name = 'default'";
                                        $res = $this->doQuery($SQL);
                                        if (!$res) {
                                                print "<b>FAILED</b>. ";
                                                print "Please make sure that the locale in pg_ts_cfg for \"default\" is set to \"$ctype\"</li>\n";
                                                dieout("</ul>");
                                        }
                                        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 (!$res) {
                                        print "<b>FAILED</b>. Specifically, \"$SQL\" did not work.</li>";
                                        dieout("</ul>");
                                }
                                print "OK</li>";
                        }

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

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

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

                        // Fix up the search paths if needed
                        print "<li>Setting the search path for user \"$wgDBuser\" ...";
                        $path = $this->quote_ident($wgDBmwschema);
                        if ($wgDBts2schema !== $wgDBmwschema)
                                $path .= ", ". $this->quote_ident($wgDBts2schema);
                        if ($wgDBmwschema !== 'public' and $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("</ul>");
                        }
                        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("</ul>");
                        }
                        define( "POSTGRES_SEARCHPATH", $path );
                }
        }


        function setup_plpgsql() {
                print "<li>Checking for Pl/Pgsql ...";
                $SQL = "SELECT 1 FROM pg_catalog.pg_language WHERE lanname = 'plpgsql'";
                $rows = $this->numRows($this->doQuery($SQL));
                if ($rows < 1) {
                        // plpgsql is not installed, but if we have a pg_pltemplate table, we should be able to create it
                        print "not installed. Attempting to install Pl/Pgsql ...";
                        $SQL = "SELECT 1 FROM pg_catalog.pg_class c JOIN pg_catalog.pg_namespace n ON (n.oid = c.relnamespace) ".
                                "WHERE relname = 'pg_pltemplate' AND nspname='pg_catalog'";
                        $rows = $this->numRows($this->doQuery($SQL));
                        if ($rows >= 1) {
                        $olde = error_reporting(0);
                                error_reporting($olde - E_WARNING);
                                $result = $this->doQuery("CREATE LANGUAGE plpgsql");
                                error_reporting($olde);
                                if (!$result) {
                                        print "<b>FAILED</b>. You need to install the language plpgsql in the database <tt>$wgDBname</tt></li>";
                                        dieout("</ul>");
                                }
                        }
                        else {
                                print "<b>FAILED</b>. You need to install the language plpgsql in the database <tt>$wgDBname</tt></li>";
                                dieout("</ul>");
                        }
                }
                print "OK</li>\n";
        }


        /**
         * 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 = '' ) {
                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 = 'Database::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];
                        }
                        $this->freeResult($res);
                }
                return $rows;
        }


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

        function indexUnique ($table, $index, $fname = 'Database::indexUnique' ) {
                $sql = "SELECT indexname FROM pg_indexes WHERE tablename='{$table}'".
                        " AND indexdef LIKE 'CREATE UNIQUE%({$index})'";
                $res = $this->query( $sql, $fname );
                if ( !$res )
                        return NULL;
                while ($row = $this->fetchObject( $res ))
                        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 array $table   String: Name of the table to insert to.
         * @param array $args    Array: Items to insert into the table.
         * @param array $fname   String: Name of the function, for profiling
         * @param mixed $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() ) {
                global $wgDBversion;

                if ( !count( $args ) ) {
                        return true;
                }

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

                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 ( $wgDBversion >= 8.2 && !$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;

        }

        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 = preg_replace( "/'/", "''", $seqName );
                $res = $this->query( "SELECT nextval('$safeseq')" );
                $row = $this->fetchRow( $res );
                $this->mInsertId = $row[0];
                $this->freeResult( $res );
                return $this->mInsertId;
        }

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

        /**
         * Postgres does not have a "USE INDEX" clause, so return an empty string
         */
        function useIndexClause( $index ) {
                return '';
        }

        # 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 = 'Database::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, $fname = "Database::deleteJoin" ) {
                if ( !$conds ) {
                        throw new DBUnexpectedError($this,  'Database::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;
                }
                $this->freeResult( $res );
                return $size;
        }

        function lowPriorityOption() {
                return '';
        }

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

        /**
         * Returns an SQL expression for a simple conditional.
         * Uses CASE on Postgres
         *
         * @param string $cond SQL expression which will result in a boolean value
         * @param string $trueVal SQL expression to return if true
         * @param string $falseVal SQL expression to return if false
         * @return string SQL fragment
         */
        function conditional( $cond, $trueVal, $falseVal ) {
                return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
        }

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

        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\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
         */
        function getSoftwareLink() {
                return "[http://www.postgresql.org/ PostgreSQL]";
        }

        /**
         * @return string Version information from the database
         */
        function getServerVersion() {
                $version = pg_fetch_result($this->doQuery("SELECT version()"),0,0);
                $thisver = array();
                if (!preg_match('/PostgreSQL (\d+\.\d+)(\S+)/', $version, $thisver)) {
                        die("Could not determine the numeric version from $version!");
                }
                $version = $thisver[1].$thisver[2];
                $this->numeric_version = $thisver[1];
                return $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 ? $res->numRows() : 0;
                if ($res)
                        $this->freeResult( $res );
                return $count ? true : false;
        }

        /*
         * 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 = <<<END
        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
END;
                $res = $this->query(sprintf($q,
                                $this->addQuotes($wgDBmwschema),
                                $this->addQuotes($table),
                                $this->addQuotes($trigger)));
                if (!$res)
                        return NULL;
                $rows = $res->numRows();
                $this->freeResult($res);
                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();
                $this->freeResult($res);
                return $rows;
        }

        /**
         * Query whether a given schema exists. Returns the name of the owner
         */
        function schemaExists( $schema ) {
                $eschema = preg_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 {
                        $owner = false;
                }
                if ($res)
                        $this->freeResult($res);
                return $owner;
        }

        /**
         * Query whether a given column exists in the mediawiki schema
         */
        function fieldExists( $table, $field, $fname = 'DatabasePostgres::fieldExists' ) {
                global $wgDBmwschema;
                $etable = preg_replace("/'/", "''", $table);
                $eschema = preg_replace("/'/", "''", $wgDBmwschema);
                $ecol = preg_replace("/'/", "''", $field);
                $SQL = "SELECT 1 FROM pg_catalog.pg_class c, pg_catalog.pg_namespace n, pg_catalog.pg_attribute a "
                        . "WHERE c.relnamespace = n.oid AND c.relname = '$etable' AND n.nspname = '$eschema' "
                        . "AND a.attrelid = c.oid AND a.attname = '$ecol'";
                $res = $this->query( $SQL, $fname );
                $count = $res ? $res->numRows() : 0;
                if ($res)
                        $this->freeResult( $res );
                return $count;
        }

        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 );
        }

        function begin( $fname = 'DatabasePostgres::begin' ) {
                $this->query( 'BEGIN', $fname );
                $this->mTrxLevel = 1;
        }
        function immediateCommit( $fname = 'DatabasePostgres::immediateCommit' ) {
                return true;
        }
        function commit( $fname = 'DatabasePostgres::commit' ) {
                $this->query( 'COMMIT', $fname );
                $this->mTrxLevel = 0;
        }

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

        function setup_database() {
                global $wgVersion, $wgDBmwschema, $wgDBts2schema, $wgDBport, $wgDBuser;

                // Make sure that we can write to the correct schema
                // If not, Postgres will happily and silently go to the next search_path item
                $ctest = "mediawiki_test_table";
                $safeschema = $this->quote_ident($wgDBmwschema);
                if ($this->tableExists($ctest, $wgDBmwschema)) {
                        $this->doQuery("DROP TABLE $safeschema.$ctest");
                }
                $SQL = "CREATE TABLE $safeschema.$ctest(a int)";
                $olde = error_reporting( 0 );
                $res = $this->doQuery($SQL);
                error_reporting( $olde );
                if (!$res) {
                        print "<b>FAILED</b>. Make sure that the user \"$wgDBuser\" can write to the schema \"$wgDBmwschema\"</li>\n";
                        dieout("</ul>");
                }
                $this->doQuery("DROP TABLE $safeschema.$ctest");

                $res = dbsource( "../maintenance/postgres/tables.sql", $this);

                ## Update version information
                $mwv = $this->addQuotes($wgVersion);
                $pgv = $this->addQuotes($this->getServerVersion());
                $pgu = $this->addQuotes($this->mUser);
                $mws = $this->addQuotes($wgDBmwschema);
                $tss = $this->addQuotes($wgDBts2schema);
                $pgp = $this->addQuotes($wgDBport);
                $dbn = $this->addQuotes($this->mDBname);
                $ctype = pg_fetch_result($this->doQuery("SHOW lc_ctype"),0,0);

                $SQL = "UPDATE mediawiki_version SET mw_version=$mwv, pg_version=$pgv, pg_user=$pgu, ".
                                "mw_schema = $mws, ts2_schema = $tss, pg_port=$pgp, pg_dbname=$dbn, ".
                                "ctype = '$ctype' ".
                                "WHERE type = 'Creation'";
                $this->query($SQL);

                ## Avoid the non-standard "REPLACE INTO" syntax
                $f = fopen( "../maintenance/interwiki.sql", 'r' );
                if ($f == false ) {
                        dieout( "<li>Could not find the interwiki.sql file");
                }
                ## We simply assume it is already empty as we have just created it
                $SQL = "INSERT INTO interwiki(iw_prefix,iw_url,iw_local) VALUES ";
                while ( ! feof( $f ) ) {
                        $line = fgets($f,1024);
                        $matches = array();
                        if (!preg_match('/^\s*(\(.+?),(\d)\)/', $line, $matches)) {
                                continue;
                        }
                        $this->query("$SQL $matches[1],$matches[2])");
                }
                print " (table interwiki successfully populated)...\n";

                $this->doQuery("COMMIT");
        }

        function encodeBlob( $b ) {
                return new Blob ( pg_escape_bytea( $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( $s );
        }

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

        function quote_ident( $s ) {
                return '"' . preg_replace( '/"/', '""', $s) . '"';
        }

        /* For now, does nothing */
        function selectDB( $db ) {
                return true;
        }

        /**
         * Postgres specific version of replaceVars.
         * Calls the parent version in Database.php
         *
         * @private
         *
         * @param string $com 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 array $options 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 );
        }

        public function setTimeout( $timeout ) {
                // @todo fixme no-op
        }

        function ping() {
                wfDebug( "Function ping() not written for DatabasePostgres.php yet");
                return true;
        }

        /**
         * How lagged is this slave?
         *
         */
        public function getLag() {
                # Not implemented for PostgreSQL
                return false;
        }

        function setFakeSlaveLag( $lag ) {}
        function setFakeMaster( $enabled = true ) {}

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

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

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

        /* These are not used yet, but we know we don't want the default version */

        public function lock( $lockName, $method ) {
                return true;
        }
        public function unlock( $lockName, $method ) {
                return true;
        }
        
        public function getSearchEngine() {
                return "SearchPostgres";
        }

} // end DatabasePostgres class