App Engine SearchAPI: java.util.concurrent.CancellationException: Task was cancelled
<p>Some of my App Engine Search API queries give a 'java.util.concurrent.CancellationException: Task was cancelled' exception. The error is reproducable.</p>

<p>I have multiple indexes. On some indexes, those queries run, on others they fail.
The query is very basic. If I run it from the admin console (<a href="https://console.cloud.google.com/appengine/search/index" rel="nofollow">https://console.cloud.google.com/appengine/search/index</a>), it gives no problem.
There is nothing special about the query. </p>

<p>The query filters on 2 atom fields: isReliable = "1" AND markedForDelete = "0", and sorts on a number field. </p>

<p>There seems nothing wrong with the code, as it runs many of such queries with no problem, far more difficult as the failing ones.</p>