在codeigniter中的所有控制器中都没有会话

Hi i have made the base controller with the name of MY_Controller and have the following code

<?php

class MY_Controller extends CI_Controller {

    public function __construct()
    {
        parent::__construct();
        $this->is_logged_in();
    }

    function is_logged_in()
    {
        $is_logged_in = $this->session->userdata('is_logged_in');
        if (!isset($is_logged_in) || $is_logged_in != true) {
            redirect('login');
        }
    }

}
?>

my login.php controller is

class Login extends CI_Controller {

    public function index()
    {
        $email = $this->input->post('email');
        $password = md5($this->input->post('password'));

        $this->load->model('users');
        $record = $this->users->authenticate_user($email, $password);

        if (count($record) && $record != false) {
            foreach ($record as $user) {
                $userdata = array(
                    'is_logged_in' => true
                 );

            }
            $this->session->set_userdata($userdata);
            redirect('index');
        }
        else
        {
            $this->load->view('login');
        }
    }

}

and all other controllers are extended like this

class Index extends MY_Controller
{
    function __construct(){
        parent::__construct();
    }
}

class Messenger extends MY_Controller
{
    function __construct(){
        parent::__construct();
    }
}

but session is just available in index controller. even all other controller also extended with MY_Controller

AnyOne help meee

Where have you initialised your session library? Load your session library in autoload.php and try.

$autoload['libraries'] = array('database', 'session'); //in autoload.php

In config.php:

$config['encryption_key'] = 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx'; //your key here

Put the session class into the autoloader configuration, in application/config/autoload.php:

$autoload['libraries'] = array('session' /* , ... */);

Then it's available automatically in each controller:

$session_id = $this->session->userdata('session_id');

and you can initialize the session data after (and only after!) each login.