session in 3.0.3 not saving userdata

I had sessions working fine in 2.x version of CI. I used to save them on client machine, but I've decided to use database. I've setup table and everything else in config file. Problem is I never get any errors. Session library is in autoload config file. In my model I use following code to put data into session:

PHP Code:

$this->session->set_userdata(array(
  'email' => $email,
  'is_logged_in' => 1)
); 


But when I try to use:

PHP Code:

var_dump($this->session->userdata()); 


I get following output:

Code:

array(1) { ["__ci_last_regenerate"]=> int(1448664996) }

nothing is added to session, no errors showing up. Can anyone help?