title: How django SESSION_SAVE_EVERY_REQUEST = True affects the performance?
body: <p>I'd like to log out user after some time (say 1h) of inactivity. To do so I can set (in django settings.py using SessionMiddleware):</p>
  
  <ul>
  <li>SESSION_COOKIE_AGE = 3600</li>
  <li>SESSION_SAVE_EVERY_REQUEST = True</li>
  </ul>
  
  <p>However, I'm afraid of the fall of performance. Therefore, my question is: "How django SESSION_SAVE_EVERY_REQUEST = True affects the performance?".</p>