Extend CI_Session_database_driver to work with extra cols in ci_sessions table

The following doesnt seem to work. I inserted a log_message() just to see if it would log, and tailed the logs, it didnt log it at all.. Am I doing this right? Still sorta new to CI

File: application/core/MY_Session_database_driver.php

PHP Code:

<?php
defined('BASEPATH') OR exit('No direct script access allowed');

class MY_Session_database_driver extends CI_Session_database_driver {

    public function write($session_id, $session_data)
    {
        log_message('error',"SESSTEST: TEST SESSION WRITE: {$session_id}");
        // Was the ID regenerated?
        if ($session_id !== $this->_session_id)
        {
            if ( ! $this->_release_lock() OR ! $this->_get_lock($session_id))
            {
                return FALSE;
            }

            $this->_row_exists = FALSE;
            $this->_session_id = $session_id;
        }
        elseif ($this->_lock === FALSE)
        {
            return FALSE;
        }

        if ($this->_row_exists === FALSE)
        {
            $insert_data = array(
                'id' => $session_id,
                'ip_address' => $_SERVER['REMOTE_ADDR'],
                'timestamp' => time(),
                'data' => ($this->_platform === 'postgre' ? base64_encode($session_data) : $session_data)
            );

            if ($this->_db->insert($this->_config['save_path'], $insert_data))
            {
                $this->_fingerprint = md5($session_data);
                return $this->_row_exists = TRUE;
            }

            return FALSE;
        }

        $this->_db->where('id', $session_id);
        if ($this->_config['match_ip'])
        {
            $this->_db->where('ip_address', $_SERVER['REMOTE_ADDR']);
        }

        $update_data = array('timestamp' => time());
        if ($this->_fingerprint !== md5($session_data))
        {
            $update_data['data'] = ($this->_platform === 'postgre')
                ? base64_encode($session_data)
                : $session_data;
        }

        if ($this->_db->update($this->_config['save_path'], $update_data))
        {
            $this->_fingerprint = md5($session_data);
            return TRUE;
        }

        return FALSE;
    }

} 


Renamed thread to a more descriptive title