python - QuerySet caching: executing get after filter was fired -

how many database queries executed following code:

q = somemodel.objects.filter(pk__in=ids) print q    # actual query executed , result             # set evaluated m = q.get(pk=ids[0]) print m    # reuse evaluated result set             # or hit database second time? 

since querysets evaluated lazily if do:

q = somemodel.objects.filter(pk__in=ids) 

...immediately folllowed (i.e., without using print):

m = q.get(pk=ids[0]) 

you'll end 1 sql query. it'll and first query second. it's safe continue adding querysets way. in django 1.3 logging revamped , can nice logging in interactive console:

>>> import logging >>> l = logging.getlogger('django.db.backends') >>> l.setlevel(logging.debug) >>> l.addhandler(logging.streamhandler()) 

which give sort of debugging info actual query executed:

(0.013) select "someapp_somemodel"."id", "someapp_somemodel"."question", "someapp_somemodel"."pub_date" "someapp_somemodel" ("someapp_somemodel"."id" in (0, 1) , "someapp_somemodel"."id" = 0 ); args=(0, 1, 0) 

don't use get on filtered queryset. if model want in queryset, use python expression (like list comprehension or filter or such) model instance out of queryset, , avoid hitting database @ second time (or many more times if iterate on list of id's).