Does Flask suffer of the problem of useless order by on some ORM prefetches ?

[LLyaudet]

Hello,

Recently I found a problem with Django and submitted a patch in a PR:
https://code.djangoproject.com/ticket/35309
django/django#17984
I also developped a work-around for old versions of Django:
https://github.com/LLyaudet/django-monkey-patches/blob/main/src/django_monkey_patches/django__orm__prefetch_without_useless_order_by.py

I don't know yet Flask details.
The idea is just that some models can have a default ordering (I assume this functionality is present in Flask also).
And that some ORM may still add this ordering in the SQL query whilst it is not needed because only a single object will be prefetched per instance of the original result set.
On very big prefetches I noticed a gain of 10 - 15 %,
since the rest of the DB query is mainly an index scan.
#ClimateChangeBrake

Can someone please dump the queries of such prefetches and see if the bug is present in Flask ?
If so submitting a PR should not be too hard.
I will try to help.
But right now, I start by warning the frameworks ORM I am aware of :)

Best regards,
Laurent Lyaudet

[ThiefMaster]

Flask does not contain an ORM. So this is (probably) an SQLAlchemy (not Flask-SQLAlchemy!) question.

But AFAIK there is no ordering at all by default (whatever order the DB gives you), and when you use .order_by() it will create a db-level ORDER BY.

[LLyaudet]

Thank you very much. I asked on SQLAlchemy.