Django 6.1 added fetch modes. With FETCH_PEERS , when you touch a foreign key on one object from a queryset, Django loads that relation for every object the queryset returned, in one query. The classic N+1 loop becomes 2 queries without you writing select_related .

My football quiz site, ExtraTime, has 621 select_related calls and 103 prefetch_related calls in its Django API, outside the tests. I wanted to know how much of that work the new mode would have done for me.

How I measured it

The API has 6,635 tests, and a lot of them call the real endpoints through Django's test client.…