title: django objects...values() select only some fields
body: <p>I'm optimizing the memory load (~2GB, offline accounting and analysis routine) of this line: </p>
  
  <pre><code>l2 = Photograph.objects.filter(**(movie.get_selectors())).values()
  </code></pre>
  
  <p>Is there a way to convince django to skip certain columns when fetching values()? </p>
  
  <p>Specifically, the routine obtains all rows of the table matching certain criteria (db is optimized and performs it very quickly), but it is a bit too much for python to handle - there is a long string referenced in each row, storing the urls for thumbnails. </p>
  
  <p>I only really need three fields from each row, but, if all the fields are included, it suddenly consumes about 5kB/row which sadly pushes the RAM to the limit.</p>