#22209: Django internals call len(queryset) instead of queryset.count()
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Reporter: gcc | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: master
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage: Accepted
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by collinanderson):
Changing the behavior of `count()` to magically check the length of the
cached data if it exists only helps if the queryset is evaluated first.
It's still better to use `len()` rather than `count()` in this case:
{{{
if queryset.count():
for x in queryset:
# do something.
}}
I've actually gone through a lot of my code and changed count() to len()
in a lot of cases it where it was actually making things slower.
It seems to me it's not worth changing anything here except for maybe
changing the warning to be less severe.
--
Ticket URL: <https://code.djangoproject.com/ticket/22209#comment:8>
Django <https://code.djangoproject.com/>
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