Django admin list does same Count query twice when there are no filters

[Alex]

The issue is due to this code:

        # Get the number of objects, with admin filters applied.
        result_count = paginator.count  # First count() query

        # Get the total number of objects, with no admin filters applied.
        if self.model_admin.show_full_result_count:
            full_result_count = self.root_queryset.count()  # Second count() query
        else:
            full_result_count = None

When the there are no filters, the same query is done for result_count and full_result_count and the value will always be the same.

[David Sanders]

Thanks Alex,

I've assigned it to you as it sounded like you were interested in submitting a PR?

[Alex]

PR: ​https://github.com/django/django/pull/16891

[Mariusz Felisiak]

Closing as "wontfix" per Simon's ​comment.

[GitHub <noreply@…>]

In 9d756afb:

Refs #34593 -- Commented that the extra count is necessary in ChangeList.get_results().

[Alex]

Bug reopened since I think I've found a solution that actually avoids the extra count query when it's not needed.

PR: ​https://github.com/django/django/pull/17568

[Mariusz Felisiak]

I still have concerns. I appreciate you'd like to reopen the ticket, but please first start a discussion on the DevelopersMailingList, where you'll reach a wider audience and see what other think, and ​follow triaging guidelines with regards to wontfix tickets.

[Simon Charette]

I share Mariusz concerns, I'm not sure it's worth trying to be extra clever here given the many hooks the admin exposes to configure returned results and the fact show_full_result_count = False can disable the extra count entirely in cases where it's expensive enough to consider this option.

[Alex]

Replying to Mariusz Felisiak:

I still have concerns. I appreciate you'd like to reopen the ticket, but please first start a discussion on the DevelopersMailingList, where you'll reach a wider audience and see what other think, and ​follow triaging guidelines with regards to wontfix tickets.

I didn't know of the mailing list. I continued the original discussion of the forum when the bug was initially opened, which according to the wontfix guidelines, it's one of the places where you can do it.
Next time I'll wait until I get more feedback (I didn't get much on the forum) or try the mailing list.Thanks for the feedback.
​https://forum.djangoproject.com/t/django-admin-list-does-count-query-twice/21100