Django Auto-Prefetching

Never worry about n+1 performance problems again

This project aims to automatically perform the correct

select_related

prefetch_related

Installation

pip install django-auto-prefetching

AutoPrefetchViewSetMixin

This is a ViewSet mixin you can use, which will automatically prefetch the needed objects from the database. In most circumstances this will be all the database optimizations you'll ever need to do:

Usage

Simply add it after your ModelViewSet class.

from django_auto_prefetching import AutoPrefetchViewSetMixin
from rest_framework.viewsets import ModelViewSet

class BaseModelViewSet(AutoPrefetchViewSetMixin, ModelViewSet):
    queryset = YourModel.objects.all()
    serializer_class = YourModelSerializer

It supports all types of relational fields, (many to many, one to many, one to one, etc.) out of the box.

Manually calling prefetch

The

AutoPrefetchViewSetMixin

SerializerMethodField

get_queryset

prefetch

import django_auto_prefetching
from rest_framework.viewsets import ModelViewSet

class BaseModelViewSet(django_auto_prefetching.AutoPrefetchViewSetMixin, ModelViewSet):
    serializer_class = YourModelSerializer
def get_queryset(self):
        # Simply do the extra select_related / prefetch_related here
        # and leave the mixin to do the rest of the work
        queryset = YourModel.objects.all()
        queryset = queryset.select_related('my_extra_field')
        return django_auto_prefetching.prefetch(queryset, self.serializer_class)

Supported Versions

Currently the project is currently being tested against Python 3.7 and 3.8 and Django 3.2 Pull Requests to support other versions are welcome.

Maturity

The project is currently being used without issues in a medium-sized Django project(20.000 lines of code)

Contributing

Contributions are welcome! To get the tests running, do the following: - Clone the repository. - If you don't have it, install pipenv - Install the dependencies with

pipenv sync --dev

pipenv shell

./manage.py test

LICENSE:

MIT