[Django] #35309: Remove Order by on models when prefetching by id

[Django]

#35309: Remove Order by on models when prefetching by id
-------------------------------------+-------------------------------------
               Reporter:  Laurent    |          Owner:  nobody
  Lyaudet                            |
                   Type:             |         Status:  new
  Cleanup/optimization               |
              Component:  Database   |        Version:  5.0
  layer (models, ORM)                |
               Severity:  Normal     |       Keywords:  prefetch order_by
           Triage Stage:             |      Has patch:  0
  Unreviewed                         |
    Needs documentation:  0          |    Needs tests:  0
Patch needs improvement:  0          |  Easy pickings:  0
                  UI/UX:  0          |
-------------------------------------+-------------------------------------
 Hello,

 I don't know if the "bug" is still here with Django 5.
 But on my version of Django, I have the following "bug" :
 Assume you have the following code :

 {{{#!python
 class A(models.Model):
     name = models.CharField(max_length=200)

     class Meta:
         ordering = ["name"]


 class B(models.Model):
     a = models.ForeignKey(A, related_name="bs", on_delete=models.CASCADE)


 a1 = A.objects.create(name="a1")
 a2 = A.objects.create(name="a2")
 a3 = A.objects.create(name="a3")
 a4 = A.objects.create(name="a4")
 a5 = A.objects.create(name="a5")
 a6 = A.objects.create(name="a6")
 a7 = A.objects.create(name="a7")

 b1 = B.objects.create(a=a1)
 b2 = B.objects.create(a=a2)
 b3 = B.objects.create(a=a3)
 b4 = B.objects.create(a=a4)
 b5 = B.objects.create(a=a5)
 b6 = B.objects.create(a=a6)
 b7 = B.objects.create(a=a7)

 bs = B.objects.all().prefetch_related("a")
 }}}

 The prefetch of as will use the order by and add useless charge on the DB
 server.
 There may be other cases than ForeignKey where the order by is useless.
 But since OneToOne inherits from ForeignKey, I don't see anything else
 right now.

 Hence, I request this enhancement, please :)
 #ClimateChangeBrake

 Best regards,
     Laurent Lyaudet
-- 
Ticket URL: <https://code.djangoproject.com/ticket/35309>
Django <https://code.djangoproject.com/>
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