title: App Engine remote API cannot fetch entities above specific fetch limit
body: <p>I am seeing some strange performance issues with a <code>model.query().fetch()</code> operation for a specific entity kind. I can fetch up to 1,200 entities using <code>.fetch(limit)</code> but at 1,201, the fetch completely breaks and never returns. To test it out, I tried running <code>fetch</code> for increasing limits:</p>
  
  <pre><code>1195 fetches took 0:00:02.832000
  1196 fetches took 0:00:02.798000
  1197 fetches took 0:00:02.948000
  1198 fetches took 0:00:02.627000
  1199 fetches took 0:00:02.746000
  1200 fetches took 0:00:02.657000
  </code></pre>
  
  <p>After 1200, nothing happens and I have to manually cancel the fetch operation. This behavior is consistent over many runs of the same test.</p>
  
  <p>I have about 14,000 entities of the given kind and each entity has about 10 properties which are mostly <em>not</em> indexed.</p>
  
  <p>The question is: Is this a bug or am I missing some insight information?</p>
  
  <p><strong>Update:</strong>
  I can add that I see the problem in two different entity kinds now. They both break exactly at <code>fetch(1201)</code></p>