On Tue, May 31, 2011 at 3:39 AM, Luke Plant <l.plant...@cantab.net> wrote:
> On 31/05/11 00:26, Alex Gaynor wrote: > > Hi all, > > > > I'm looking at r16297 (https://code.djangoproject.com/changeset/16297), > > and I don't like this approach, I understand what it is trying to > > accomplish, but it has several downsides that don't appear to have been > > considered: > > > > a) On CPython a class object is pretty large, and they are very easy to > > get into reference cycles that won't be collected for a while. > > b) On PyPy (and IronPython AFAIK, and *maybe* CPython) creating a new > > class for each instance can lead to poor performance because they > > prevent reusing various caches, or can cause overspecialization. > > Thanks for pointing out these, I wasn't aware of these issues. > > If we kept the pre-made request subclasses around in a cache and re-used > them, would it fix these problems? Something like: > > --- > > _request_subclass_cache = {} > > def add_user_property(request): > try: > SubClass = _request_subclass_cache[request.__class__] > except KeyError: > class SubClass(request.__class__): > user = LazyUser() > _request_subclass_cache[request.__class__] = SubClass > request.__class__ = SubClass > return request > > ---- > > Regards, > > Luke > > -- > "The truth will set your teeth free." (Calvin and Hobbes) > > Luke Plant || http://lukeplant.me.uk/ > > -- > You received this message because you are subscribed to the Google Groups > "Django developers" group. > To post to this group, send email to django-developers@googlegroups.com. > To unsubscribe from this group, send email to > django-developers+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/django-developers?hl=en. > > I came up with an alternate approach that is much simpler: http://paste.pocoo.org/show/398303/ , all tests pass with this. Any objections to checking this in? Alex -- "I disapprove of what you say, but I will defend to the death your right to say it." -- Evelyn Beatrice Hall (summarizing Voltaire) "The people's good is the highest law." -- Cicero -- You received this message because you are subscribed to the Google Groups "Django developers" group. To post to this group, send email to django-developers@googlegroups.com. To unsubscribe from this group, send email to django-developers+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/django-developers?hl=en.
