title: Session being lost after multiple (cancelled) POST requests
body: <p>We're using an external Ubuntu server w/ Memcached for our session storage. Since we changed over from database sessions, we've had random complaints from users who are being logged out.</p>
  
  <p>The issue:</p>
  
  <ol>
  <li>Users are being logged out before their session should expire. In some cases, they are being logged out a minute or two after they've logged in.</li>
  <li>No errors are appearing in our web server logs or our Memcached logs.</li>
  <li>Their session ID remains the same after they've been logged out.</li>
  </ol>
  
  <p>Today, one of our users stumbled upon a way to reproduce the behavior. On a page that allows them to set a custom date range, they were repeatedly pressing a "previous day" button that sends off a POST request with each click. For example, if you click said button 20 times, it'll send off 20 POST requests, 19 of which will be cancelled before the last one is completed successfully. As soon as the final request is completed, it seems as though all of the session variables are lost.</p>
  
  <p>My php.ini (CGI) settings:</p>
  
  <pre><code>session.save_handler = memcache
  session.save_path = "tcp://OURSERVERIP:11211?persistent=1&amp;weight=1&amp;timeout=1&amp;retry_interval=15"
  </code></pre>
  
  <p>Note: The POST request is loading an iframe on the same domain.</p>
  
  <p>Update: Also seem to be getting an issue with users being logged in as one another. Session ID conflict?</p>