title: Why does a barebones Rails controller block if the database is down?
body: <p>I have a simple Rails controller which does not depend on the database.</p>
  
  <pre><code>class PingController &lt; ActionController::Base
    def ping
      render text: 'The service is up'
    end
  end
  </code></pre>
  
  <p>However, when the database goes down, this controller action blocks. 
  Why does this happen?</p>