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
36507	Document that only the base queryset’s prefetch_related() is preserved when using union()	Clifford Gama	Chris M	When using QuerySet.union() (possibly also `intersection()` and `difference()`) in Django, any `prefetch_related()` applied to the second (and third, etc) queryset is silently ignored. See [https://forum.djangoproject.com/t/using-union-with-querysets-that-have-a-custom-prefetch-object/41638 forum thread in which it was suggested to open a documentation ticket]. A docs improvement should also likely include the workaround for using `Q` objects to do all prefetches in the base qs (where possible), which is suggested by Simon in the forum.	Cleanup/optimization	assigned	Database layer (models, ORM)	5.2	Normal		prefetch_related, union	Sniom	Accepted	1	0	0	1	0	0