Automatically determine select_related and prefetch_related on ModelSerializer

[cancan101]

What do you think about adding something along the lines of encode/django-rest-framework#1964 to drf-extensions?

@thedrow offers a pretty good write-up on a workable approach: encode/django-rest-framework#1964 (comment)

[chibisov]

Interesting. I think it should be splitted to two stages:

1. get_prefetch_related_fields and get_select_related_fields serializer's methods.
2. Mixin for viewset that extends get_queryset method and applies select_related or prefetch_related to queryset based on those serializer's methods
3. Maybe some automatic magic in serializer itself that turned off by default.

But I would say it's too magic. For example, in most cases I use serializers in ViewSets and use prefetching facilities explicitly:

class UserViewSet(viewsets.ReadOnlyModelViewSet):
    serializer_class = UserSerializer
    queryset = queryset.prefetch_related('groups__permissions')

[kevin-brown]

This may be something that should be in its own third party package, though it would be nice to see it be in drf-extensions.

For example, in most cases I use serializers in ViewSets and use prefetching facilities explicitly:

I wish I could say that most users do this as well, but the Stack Overflow questions keep coming.

[cancan101]

TBH, I understand how select_related works and I was able to diagnose the N+1 issue as a missing select_related on the queryset, but I was a little surprised at first that drf did not do this automatically when using nested serializer or even just SlugRelatedField. That is why I filed the issue originally on drf.

[chibisov]

By and large I think it's too magic. Closing this issue.