I was poking around in our (Votizen's) use of signals and thinking about making some tooling so that signal usage was a bit more transparent.
In doing so, I noticed that GenericForeignKey hooks the model pre_init signal. It does that because GFK needs a chance to munge kwargs from the GFK field name to the content_id and object_id fields. Signal dispatch with zero receivers is much much faster than with 1 or more receivers, and pre_init is fired quite a lot. Pretty much every decent sized project I've worked on has used GFK, so I imagine this is a large sap on performance overall. Similarly, I just noticed that ImageField does a similar thing, setting dimension values in post_init. I think we could get a significant performance win if, instead of using pre_init/post_init here, we changed Model.__init__ to call a per-field hook that could munge the Model.__init__ kwargs. SomeField.model_pre_init(instance, args, kwargs) or maybe for symmetry with contribute_to_class: SomeField.contribute_to_instance(instance, args, kwargs) We could store which fields have these hooks upon ModelBase.__new__ construction and so skip most fields and overhead in __init__. I'm happy to make a pull request but checking here to see if there's any pushback. -- 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.
