Django queryset and generator

Question

Just out of the blue I wonder if the following way of iterating through a result set using generator will cause any positive or negative impact against normal iteration?

eg.

def all_items_generator():
  for item in Item.objects.all():
    yield item

for item in all_items_generator():
  do_stuff_with_item(item)

against:

for item in Item.objects.all():
  do_stuff_with_item(item)

Answer 1

The former will be slower, since it will create a list containing all the models and then yield them one at a time, whereas the latter will just use the list directly. If you want a generator then you should use QuerySet.iterator() instead.

Answer 2

No. Other than the fact that it's more verbose, redundant, and not particularly useful (in the context of the generator you provided).

When you do Item.objects.all() in a for, they're iterated using iterator with query caching (source). If you don't want the results to be cached, use iterator() like Ignacio recommends.