admin_performance.rst

ORM Gotchas

N+1 Queries

Caching

Eager evaluation

Lazy evaluation

book.author.id book.author_id

qs.exist()

.iterator()

bulk operations

bulk update wont call save or signals

Runpython wont call these

get only what you need

values_list()

enable query logging

Disable full count

show_full_result_count = False

Fetch only required fields

When a model is registered in admin, django tries to fetch all the fields of the table in the query. If there are any joins involved, it fetch fields of the joined tables also. This will slow down the query when the table size is big or number of results per page is more.

To make queries faster, we can limit the queryset to fetch only required fields.

class BookAdmin(admin.ModelAdmin):
    def get_queryset(self, request):
        qs = super().get_queryset(request)
        qs = qs.only('id', 'name')
        return qs


admin.site.register(Book, BookAdmin)