#35309: Remove Order by on models when prefetching by id
-------------------------------------+-------------------------------------
Reporter: Laurent Lyaudet | Owner: nobody
Type: | Status: closed
Cleanup/optimization |
Component: Database layer | Version: 5.0
(models, ORM) |
Severity: Normal | Resolution: invalid
Keywords: prefetch order_by | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Changes (by Simon Charette):
* resolution: => invalid
* status: new => closed
Comment:
`Meta.ordering` is working as expected, please
[https://docs.djangoproject.com/en/5.0/ref/models/options/#ordering refer
to its documentation] and associated warning
> Ordering is not a free operation. Each field you add to the ordering
incurs a cost to your database. Each foreign key you add will implicitly
include all of its default orderings as well.
If you don't want this implicit behaviour then don't use `Meta.ordering`.
If you want to keep using it but not for particular prefetches than use
`Prefetch` objects with a queryset that explicitly calls `order_by()` to
disable ordering.
{{{#!python
B.objects.prefetch_related(Prefetch("a", A.objects.order_by()))
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/35309#comment:1>
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