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
33848	Migration StateApps.clone deepcopy too many objects	Iuri de Silvio	nobody	"`StateApps.clone` execute two slow deep copies. The first one copy all models. The second one copy app configs, that include all apps and the specific app models.

In my application, with ~250 models, this deepcopy is around 5% of migration time. I was able to cleanup `StateApps` before copy, to not copy all models and apps every operation again. After the optimization, it takes less than 1% of migration time.

https://github.com/django/django/blob/d4c5d2b52c897ccc07f04482d3f42f976a79223c/django/db/migrations/state.py#L683
"	Cleanup/optimization	new	Migrations	4.0	Normal				Unreviewed	1	0	0	0	0	0