On Tue, Mar 29, 2011 at 2:27 PM, Fabian Büchler <[email protected]> wrote: > I've analyzed the query using pgAdmin and it seems the most time is being > spent with a the GroupAggregate. > This is because of so many columns being listed in the GROUP BY clause. > Creating two-column indexes over event_id and date or some other > combinations I've tried did not gain any perforamance. > > Thus I've tried to get rid of some by just selecting some columns via > "only(...)". Strangely this does not have any effect on the GROUP BY clause. >
only() does not affect the generated query in any way -- it would be a bug if it did. > On the other hand, if I use "values(...)" the GROUP BY clause shrinks to > only the named columns (but still being listed twice each). > There's already a ticket for the duplicated GROUP BY columns in the Django ticket tracker: http://code.djangoproject.com/ticket/15709 > The QuerySet.only() method not limiting the GROUP BY clause to the named > columns seems like a "bug" (or inefficiency) in the ORM to me. Is that valid > at any rate? > Not sure about that. I'd say it isn't a bug because this could potentially cause different results depending on the table and table content. Matthias -- Django CMS building toolkit: http://www.feinheit.ch/labs/feincms-django-cms/ -- You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/django-users?hl=en.
