title: why a collection exists but can not find in show collections?
body: <p>In the mongo shell, I can find records from collection <code>stat</code> by using such commands: </p>
  
  <pre><code>use gm;
  gm.stat.find({});
  </code></pre>
  
  <p>but <code>stat</code> is not listed in show collection results.</p>