From 517d3bb4dd17e9c51690c98d747b86a0ed8b2fbf Mon Sep 17 00:00:00 2001 From: Juan Alvarez Date: Tue, 15 Aug 2023 16:53:30 -0300 Subject: Fixed #34779 -- Avoided unnecessary selection of non-nullable m2m fields without natural keys during serialization. By using `select_related(None)` instead of `select_related()`, the unnecessary joins are completely avoided. Note that the current tests already covers the change, when the field is not `null=True`. Regression in f9936deed1ff13b20e18bd9ca2b0750b52706b6c. --- django/core/serializers/python.py | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'django/core/serializers/python.py') diff --git a/django/core/serializers/python.py b/django/core/serializers/python.py index 0dc504aa34..7ec894aa00 100644 --- a/django/core/serializers/python.py +++ b/django/core/serializers/python.py @@ -80,7 +80,10 @@ class Serializer(base.Serializer): def queryset_iterator(obj, field): return ( - getattr(obj, field.name).select_related().only("pk").iterator() + getattr(obj, field.name) + .select_related(None) + .only("pk") + .iterator() ) m2m_iter = getattr(obj, "_prefetched_objects_cache", {}).get( -- cgit v1.3