CodeIgniter : Loosing session data after login

In Codeigniter after login I am storing all the data into session and redirecting to some controller.But i am loosing all values in that controller and code redirect back to login page. I try every trick to debug this issue but fail!!! I don't know from where i got idea to reduce some values from session, Magic.. it start working fine.. Now my question is- why this is happening? Is there any upper limit of values to be store in session in codeIgniter? Explanation: By default CodeIgniter stores the session data in a cookie, which has an upper limit of 2KB-4KB in size depending on browser. If you are trying to store more than 4KB of data in the session you will start running into issues. Solution: The easiest solution is to store the session details in the DB.The CodeIgniter session documentation details the process for storing the session in the's a matter of setting up a table, and changing a couple of config parameters. Below are the changes you need to do- Update below variable in Config file (application/config/config.php):
$config['sess_use_database'] = TRUE;
$config['sess_table_name']   = 'ci_sessions';
Created new table for storing session-
session_id varchar(40) DEFAULT '0' NOT NULL,
ip_address varchar(45) DEFAULT '0' NOT NULL,
user_agent varchar(120) NOT NULL,
last_activity int(10) unsigned DEFAULT 0 NOT NULL,
user_data text NOT NULL,
PRIMARY KEY (session_id),
KEY `last_activity_idx` (`last_activity`)
[si-contact-form form='1']

Your feedbacks are most welcome..