title: How about the performance by using date or int in ElasticSearch?
body: <p>I have an index with 20million docs. The index have 4 fields like this:</p>
  
  <pre><code>id 
  title 
  type 
  created_time
  </code></pre>
  
  <p>I query this index and sort by <code>created_time</code>. And here is my question:</p>
  
  <p>What's the difference by using <code>created_time</code> as date or timestamp? Since there isn't timestamp in ES, I use int to describe <code>created_time</code>.</p>
  
  <p>Thank you.</p>