Redirect create a new session row in the database

[eluser]it.peds[/eluser]
I have tried with different config, autoload or load at controller construct, and different browsers, but all have a same result, <b>

Code:

redirect('another_controller')

creates a new row with every field is same except session_id & userdata in the session table in the database</b>

I store log-in information in the userdata. I vardump

Code:

$this->session->all_userdata()

after passing the verification, and I can see the stored userdata; however, I vardump it again in the redirected controller, and all I see is a new session without any userdata and with different session_id, even the last_activity is same (should this be a timestamp?).

I am using CI 2.1.2 to develop a website that requires log-in. Please suggest either how to fix this redirect + session problem or another way to remember an user is logging in. Thank you very much.

BTW, I just realize refreshing pages also creates a new session row. And forget to mention, even with or without .htaccess to hide the index.php, same result.