ModelMultipleChoiceField does O(n) queries where O(1) will suffice

[Alex Gaynor]

Which is hugely inefficient, selecting 20 items already means you're going outside the reasonable limits for SQL queries.

[Joes]

Had to develop similar solution (and custom widget) to get rid of mentioned issue.

[Jacob]

This isn't quite correct yet. In the patched version, self.queryset.filter(pk=pk) will never raise the ValueError the try/except block is catching against, so the logic is incorrect somewhere.

[Alex Gaynor]

Jacob's complaint was not accurate as the tests found here:

​http://code.djangoproject.com/browser/django/trunk/tests/modeltests/model_forms/models.py#L827

Still pass, and they obviously rely on that ValueError logic being correct(the reason this works is get_db_prep_lookup is called on the object being added to the QuerySet, not on the Query being executed).

[Jacob]

(In [10582]) Fixed #10156: ModelMultipleChoiceField.clean now does a single query instead of O(N). Thanks, Alex Gaynor. Also, I ported a few more doctests to unittests.

[anonymous]

​r10482 uses filter which doesn't return same order as pks given, where as previous implementation appended values to the end. e.g.: clean([3,2]) -> {object 3, object 2} where as new implementation returns {object 2, object 3}
Its a changed in the behavior, which I was using ...

[Alex Gaynor]

This ticket was fixed, if you believe there is a new issue please file a new ticket.

[Jacob]

Milestone 1.1 deleted