CODEWITHSUNDEEP
pythonmysqldjangoperformance
Nick
Nick

Reputation: 1934

Django Query Performance Filtering Vs Foreign Key Set Lookup

I'm wondering which, if either, query is faster in Django. I have a Location model and a User model. Users are foreign keyed to Locations, so each Location can have a 'locationuser_set' attribute.

Which, if either, is faster if I have thousands of Users?

Query 1:

location = Location.objects.get(id=<id>)
users = location.user_set.all()

Query 2:

users = User.objects.filter(location_id=<id>)

Upvotes: 3

Views: 766

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 600026

Query 2 is exactly equivalent to the second line of Query 1. But since Query 1 also includes the first line, which does a separate Location lookup, it is necessarily slower.

If you don't need the actual location object, then 2 is definitely the way to go.

Upvotes: 5

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