title: redis hangs on flushall command
body: <p>I used FLUSHALL command to drop my redis cache. From doc:</p>
  
  <blockquote>
    <p>Delete all the keys of all the existing databases, not just the
    currently selected one. This command <strong>never fails</strong>.</p>
  </blockquote>
  
  <p>But it hangs on my huge redis instance(in my case about to 20GB) and than i terminate redis server, clear redis backup dir and start redis server back. Everything seems good but is it good way to do so? And why flushall hang?</p>