#35442: N+1 queries from RelatedManager + only("pk")
-------------------------------------+-------------------------------------
Reporter: REGNIER Guillaume | Owner: nobody
Type: Uncategorized | Status: new
Component: Database layer | Version: 4.2
(models, ORM) |
Severity: Normal | Resolution:
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
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Comment (by Simon Charette):
This relates to #20927, #18177, and at least another ticket that asked for
`"company_id"` to be implicitly included in the `only` call that I just
can't find anymore.
I think we should try to resolve that in a different way and a potential
solution could be something like
{{{#!python
diff --git a/django/db/models/query.py b/django/db/models/query.py
index cb5c63c0d1..9390d2242d 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -119,6 +119,7 @@ def __iter__(self):
),
)
for field, related_objs in
queryset._known_related_objects.items()
+ # if not is_deferred(field)
]
for row in compiler.results_iter(results):
obj = model_cls.from_db(
}}}
But in order to work properly it would require a refactor of
`known_related_objects` as the current approach is naive wrt/ to how it
namespace related objects by field as the same model field can be included
multiple times in the the same queryset (e.g. see #35356)
--
Ticket URL: <https://code.djangoproject.com/ticket/35442#comment:1>
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