Question

I’ve got a an app where I’m storing posts and their authors. Very
straightforward each post has one author model.

The problem is this: I fetch the last 10 posts using one call, using
fetch() with limit = 10. But when I print them out, GAE uses 10 extra
gets to access the author details, because the author object is a
reference property on the post… a classic n+1 query
scenario – 1 query to get 10 posts and then 10 queries to get each
author.

Is there any way I can iterate over my posts to collect just the
author object keys, so I can load them all up at one go using

db.get(all_author_keys)

Answer 1

See my response to this question just a couple hours ago — a Q almost identical by amazing coincidence by this one, though by a different poster.

In short, to do this, use the get_value_for_datastore of the Property object.