id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
37343	Use FETCH_ASYNC as the default fetch mode for async ORM queries (replace SynchronousOnlyOperation on implicit related fetches)	Mykhailo Havelia		"**Description:**

Django 6.1 added fetch modes (FETCH_ONE, FETCH_PEERS, FETCH_RAISE). I'd like to propose using them to improve the async ORM experience.

**Problem**

Async Django ORM doesn't support the active-record pattern for related objects. Accessing an unloaded relation triggers an implicit synchronous fetch:


{{{
book = await Book.objects.aget(pk=1)
book.author.name  # implicit FK fetch
}}}

Without select_related() / prefetch_related(), this raises SynchronousOnlyOperation. That error is confusing here: it describes the mechanism (a sync DB call inside an async context) rather than the actual mistake (accessing a relation that wasn't loaded). A developer new to async Django can't easily tell from it what to do next (or it can make a silent sync call if DJANGO_ALLOW_ASYNC_UNSAFE is true).

**Proposal**

When a query runs in async mode, default its fetch mode to FETCH_ASYNC instead of relying on the implicit-sync path. Accessing an unloaded field would then raise FieldFetchBlocked with a message pointing to the fix


{{{
FieldFetchBlocked: 'author' isn't fetched. Load it with select_related()/prefetch_related().
}}}

This turns a low-level error into an actionable ORM error, at the exact spot where the developer needs guidance.

**Context**

This came up in django-async-backend. We can hardcode a custom fetch function there to raise our own error, but it would be much better to have consistent behavior inside Django itself.

"	Cleanup/optimization	new	Database layer (models, ORM)	6.1	Normal		async orm	Mykhailo Havelia Simon Charette	Accepted	0	0	0	0	0	0