title: Turn off AppEngine (Java) sessions for certain requests
body: <p>We're using <a href="https://developers.google.com/appengine/docs/java/config/appconfig#Enabling_Sessions" rel="nofollow">sessions</a> in our GAE/J application. Over the weekend, we had a large spike in our datastore writes that appears to have been caused by a large number of _ah_SESSION entities being created (about 100-200 every minute). Near as we can tell, there was a rogue task queue creating them because they stopped when we purged the queue. The task was part of a <a href="http://code.google.com/p/appengine-mapreduce/" rel="nofollow">mapper</a> process we run hourly.</p>
  
  <p>We don't need sessions in that hourly mapper (or indeed in any of our task queues or cron jobs or many other requests). Is there a way to disable creating a session for selected URLs?</p>