title: Queries by key and iterating over objects in AppEngine
body: <p>AppEngine docs note that "Queries that return keys are faster and cost less CPU than queries that return full entities."</p>
  
  <p>Which of these two is the more desired way to fetch and iterate over a number of objects from the data store?</p>
  
  <pre><code>query_keys = Person.all(keys_only=True)
  query_keys.filter('name = ', person_name)
  query_keys.order("__key__")
  
  people = db.get(query_keys)                                                
  for p in people:
     #read properties of the person object
     print p.name
  </code></pre>
  
  <p>Vs </p>
  
  <pre><code>query = Person.all()
  query.filter('name = ', person_name)                   
  query.order("__key__")
  
  for p in people:
     #read properties of the person object
     print p.name
  </code></pre>