I don't think your issue has anything to do with proxy models. You'll get the exact same error if your use Parent.objects instead of Child.objects as both will generate the same SQL:
SELECT * FROM parent LEFT JOIN foreign ON parent.foreign_id = foreign.id FOR UPDATE OF parent In this case "parent" cannot be selected for update since it's "foreign_id" column, which is "nullable", is implied in an outer join. PostgreSQL simply doesn't support that and you'll have to rethink your data model if this is something you need to achieve[0] Cheers, Simon [0] https://www.postgresql.org/message-id/[email protected] Le mercredi 23 septembre 2020 à 12:15:35 UTC-4, [email protected] a écrit : > Hello. > I just wanted to know, whether I run into a bug, and whether I should > report it. > > Normally select_for_update and select_related try to lock all affected > rows in all tables. One can specify "of" for select_for_update to limit > tables to lock (to prevent locking nullable relations). > > Recently a bug was fixed, which allowed to lock parent nodes with > multitable inheritance. But what about proxies? For me the following does > not work. Should it? > > class Parent(Model): > foreign = ForeignKey(Foreign, null=True, blank=True) > > class Child(Parent): > class Meta: > proxy = True > > class Foreign(Model): > pass > > with transaction.atomic(): > > Child.objects.select_for_update(of=('self',)).select_related('foreign').get(pk=1) > > So the (pseudo) code above fails with a message "FOR UPDATE cannot be > applied to the nullable side of an outer join" > > So is this expected behaviour or a bug? What are possible workarounds for > that? > -- You received this message because you are subscribed to the Google Groups "Django users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/b9e15c75-8ec7-4ca2-a9a9-21f0d58f64a3n%40googlegroups.com.
