How to have a session that never expires ?

I tried your solution but always the same issue, after a short time the session expires...
I don't get it 

When you say "the session expires" you mean that the session data is gone?

I have a GitHub Repository that is designed to test CodeIgniter (v3.x.x) session configuration. It contains one controller and one view file. Give it a try it may help you determine if you have a config issue or some other "logic" problem.

When i say the session expires, i mean when the user logins, the script does that : 

PHP Code:

$this->session->set_userdata('user_id', $result['id']); 


then that to check if the logged session is still running : 

PHP Code:

if(!empty($this->session->user_id)):
echo "LOGGED";
endif; 


Very classic i guess, no ?

So for my test, i just login, let the tab opened and comeback X hours after, reload the page to see if i'm still logged or not. When it's 30 mins after, i'm still logged, but when it's after X hours, i'm not !

Thanks for the github, i will take a look and give it a try !