Multiple databases, codeigniter does not re-select the database

[eluser]Hernando[/eluser]
This is the original version

Code:

/**
     * Execute the query
     *
     * @access    private called by the base class
     * @param    string    an SQL query
     * @return    resource
     */    
    function _execute($sql)
    {
        $sql = $this->_prep_query($sql);
        return @mysql_query($sql, $this->conn_id);
    }

What version of Codeigniter do you use?. Second parameter of mysql_query is the connection