Could bulk_update() aggregate the pk's in WHEN clauses?

[Vlada Macek]

I'd like to ask if there's a reason why instead of this

                when_statements = []
                for obj in batch_objs:
                    attr = getattr(obj, field.attname)
                    if not hasattr(attr, "resolve_expression"):
                        attr = Value(attr, output_field=field)
                    when_statements.append(When(pk=obj.pk, then=attr))

this code isn't used

                when_updates = defaultdict(list)
                for obj in batch_objs:
                    attr = getattr(obj, field.attname)
                    if not hasattr(attr, "resolve_expression"):
                        attr = Value(attr, output_field=field)
                    when_updates[attr].append(obj.pk)
                when_statements = [
                    When(pk__in=pks, then=attr) if len(pks) > 1 else When(pk=pks[0], then=attr)
                    for attr, pks in when_updates.items()
                ]

in bulk_update(). Instead of having WHEN for each pk, aggregated WHEN ("t"."id" IN (14679095, 14679134, 14679335, ...)) THEN ... would be produced.

That could massively reduce the query length.

[Natalia Bidart]

Hello Vlada Macek, thank you for your ticket!

This issue tracker has the goal to track bugs about Django, so we often ask contributors to post their questions and/or discuss Django internals in the Django Forum instead. With that in mind, would you consider starting a new conversation in the ​Django Internals category? You'll reach a wider audience and likely get extra feedback using that approach.

I'll be closing this ticket as invalid following the ​ticket triaging process, but if the forum conversation reaches a conclusion that this is a desired change, please come back to this issue pasting the link of the forum thread.

[Vlada Macek]

Thank you, Natalia.
Ok, while I don't see why this topic is invalid under the rules you reference and I think I correctly used the Optimization type, I opened the topic in the forum.

​https://forum.djangoproject.com/t/could-bulk-update-aggregate-the-pks-in-when-clauses/27093

[Natalia Bidart]

#35399 was a duplicate of this one.