Make save faster

[novalis]

Save presently does a bunch of work each time to set up a manager for update. This can be cached. A patch is attached.

[Honza Král]

Constructing a queryset every save() (which your patch doesn't avoid) is not such an expensive operation that it would require caching.

If you feel the need to do this in your model, do it in your save method and use the outcome to set force_insert or force_update.

[novalis]

It is in fact a fairly large percentage of the time for save in my benchmark. My case is perhaps unusual in that my model has a default ordering, but I think this is fairly common.

I can't do it in my save method, I think, because that doesn't work when I am loading fixtures. So this patch makes tests faster as well as the live site.

[Alex Gaynor]

An attribute lookup *is not that expensive* which is all this patch is doing. Marking as wontfix again, if you disagree please take this to the django-developers mailing list.