title: mongodb: how can I see the execution time for the aggregate command?
body: <p>I execute the follow mongodb command in mongo shell</p>
  
  <pre><code>db.coll.aggregate(...)
  </code></pre>
  
  <p>and i see the list of result. but is it possible to see the query
  execution time? Is there any equivalent function for explain method for aggregation queries.</p>