#31666: Combine prefetch_related queries for FK's to the same target model
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Reporter: Adam (Chainz) | Owner: nobody
Johnson |
Type: | Status: new
Cleanup/optimization |
Component: Database layer | Version: master
(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 Gordon Wrigley):
To my mind the duplicate objects in memory is kinda a feature.
Specifically it seems desirable to me that a prefetch related clause only
changes performance not behaviour. Particularly it seems concerning that
adding a prefetch_related to this (very contrived) example would change
it's behaviour:
{{{
b = Book.objects.get()
b.author1.weight = 90
b.author2.weight = 50
print(b.author1.weight + b.author2.weight)
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/31666#comment:1>
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