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
27624	Optimize ORM by using more immutable data structures	Adam Johnson	Adam Johnson	"Django's `QuerySet` and `Query` classes spend most of their lifetime being copied, and each step in the building of a query, a very limited selection of the attributes get changed. As such they incur time and memory overheads from using mutable datastructures that require a copy operation for each step. Mutable data structures also introduce the possibility for bugs if they get shared or mutated in the wrong places. Finally `QuerySet` and `Query` are inconsistent and mix mutable and immutable datastructures for similar attributes.

I'm going to look at converting them to using just immutable ones (tuple instead of set, frozenset instead of set, etc.).
"	Cleanup/optimization	assigned	Database layer (models, ORM)	1.10	Normal			me@… Keryn Knight	Accepted	0	0	0	0	0	0