#35442: N+1 queries from RelatedManager + only("pk")
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Reporter: REGNIER Guillaume | Owner: nobody
Type: Uncategorized | Status: closed
Component: Database layer | Version: 4.2
(models, ORM) |
Severity: Normal | Resolution: duplicate
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):
Accessing objects though a related manager should still allow for `only`
to work as expected. The fact that the ORM doesn't even warn you when it
silently issues queries on field deferral leaks (#22492) makes this
behavior really insidious and prevents sage usage of related managers as
Guillaume brought up.
I think the the ORM should either have `RelatedManager.only` include the
reverse field implicitly (which we've kind of rules out against in #33835)
or we should find a way to more safely assign known related objects in the
face of deferred fields.
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Ticket URL: <https://code.djangoproject.com/ticket/35442#comment:6>
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