title: Flask app slow if used by a small number of users in parallel
body: <p>I have a Flask app with a few simple Jinja2 templates. In addition I use Flask-Assets/pyScss for CSS.</p>
  
  <p>If a single users works with the app then everything works great. If a small number of people (less than 20) access the app in parallel then the response time <em>sometimes</em> goes way up and it feels like the server is not responding at all.</p>
  
  <p>I tried:
  <code>
  ab -n 1000 -c 20 http://myapp
  </code></p>
  
  <p>But I wasn't able to reproduce the issue "artificially". How would you debug this kind of problem? </p>