#30874: Allow disabling of lazy loading of model and related fields on querysets
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Reporter: Rowan Seymour | Owner: nobody
Type: Uncategorized | Status: new
Component: Uncategorized | Version: 2.2
Severity: Normal | 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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Lazy field fetching can be super convenient but also a liability at scale.
For example:
{{{
for book in Book.objects.only("id").all():
book.author # lazily fetches author field
book.categories.all() # lazily fetches related field
}}}
You might be trying to optimize your query by using `only` but then later
you reference another field and don't realize there's now a new DB hit for
every object you've loaded.
What would be really useful in situations like this to disable lazy
fetching of fields and related fields, so if you haven't included them
with `only` or `select_related`, the field access raises an exception.
{{{
for book in Book.objects(allow_lazy=False).only("id").all():
book.author # raises exception
}}}
Indicating that you need to correct the query..
{{{
for book in Book.objects(allow_lazy=False).only(''id",
"author").select_related("categories").all():
book.author
book.categories.all()
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/30874>
Django <https://code.djangoproject.com/>
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