<p dir="auto">If I am not mistaken, after enabling _ttl &amp; _timestamp, one must also then add a request for the _ttl &amp; _timestamp fields (and _source, otherwise, it disappears) to (every) search request thereafter in order to get the values - if we want to display them.</p>
<p dir="auto">Is there a downside to having them included with the other hit fields (_id, _index, _type, _score) automatically?</p>
<p dir="auto">It seems to me to be the most intuitive behaviour.<br>
At least thats what I (and my pair) were expecting - and we had to go on a bit of a tour of stackexchange to find out why it wasnt behaving like that what hoops we had to jump through</p>
<p dir="auto">When you search or GET to retrieve documents you don't get back the value for <code class="notranslate">_parent</code> field (or <code class="notranslate">_routing</code> for that matter) which is part of the essential metadata. Meaning the document cannot be retrieved or updated without the value. This is breaking some functionality, example use cases:</p>
<ul dir="auto">
<li>reindex (results of <code class="notranslate">scan</code> being fed into <code class="notranslate">bulk</code>) cannot work</li>
<li>persistence layers on top of elasticsearch cannot update a document they retrieved from ES without additional info/queries</li>
<li>you cannot GET a document you searched for (for example to retrieve fields you excluded)</li>
</ul>
<p dir="auto">I believe it would be worth the cost to retrieve the value of <code class="notranslate">_parent</code> field when retrieving a child document.</p>