id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
20950	Use OrderedDicts in ORM only when needed	Anssi Kääriäinen	nobody	"Initializing OrderedDicts seem to be really slow, at least on Python 2.7. By instantiating OrderedDicts in Query only when needed one can save considerable time. For example model_save_existing benchmark is 1.3x faster, qs_filter_chaining 1.35x faster. Nearly all of the query_ benchmarks have at least 10% speedup.

Patch at https://github.com/akaariai/django/tree/ordered_dict_on_need. Together with splitted_clone branch this gives over 1.5x speedup to model_save_existing.

There might be some cleaner way to implement the ""initiate only on need"" for Query._aggregates and Query._extra. Ideas welcome.

Ill accept this directly as this seems like a good idea to do. This trades code-cleanness for performance, but in this particular case I think it is worth it."	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	fixed			Accepted	1	0	0	0	0	0