title: Why codeigniter session expires frequently ? also user is active on site
body: <p>I'm using codeigniter for my app. development. </p>
  
  <p>These are the session settings. I'm using DB session.</p>
  
  <pre><code>$config['sess_cookie_name']= 'ci_session';
  $config['sess_expiration']= 7200;
  $config['sess_encrypt_cookie']  = FALSE;
  $config['sess_use_database']    = TRUE;
  $config['sess_table_name']= 'ci_sessions';
  $config['sess_match_ip']= FALSE;
  $config['sess_match_useragent'] = TRUE;
  $config['sess_time_to_update']  = 300;
  </code></pre>
  
  <p>I am not using AJAX or dynamic resources loading the session library.
  Also I have checked session data,all data are saving in DB.</p>
  
  <p>This is working well on localhost.</p>