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
36526	bulk_update uses more memory than expected	Anže Pečar		"I recently tried to update a large number of objects with:

{{{
things = list(Thing.objects.all()) # A large number of objects e.g. > 1_000_000
Thing.objects.bulk_update(things, [""description""], batch_size=300)
}}}

The first line above fits into the available memory (~2GB in my case), but the second line caused a SIGTERM, even though I had an additional 2GB of available memory. This was a bit surprising as I wasn't expecting bulk_update to use this much memory since all the objects to update were already loaded.

My solution was:

{{{
for batch in batched(things, 300):
     Thing.objects.bulk_update(batch, [""description""], batch_size=300)
}}}

The first example `bulk_update` used 2.8GB of memory, but in the second example, it only used 62MB.

[https://github.com/anze3db/django-bulk-update-memory A GitHub repository that reproduces the problem with memray results.]

This might be related to https://code.djangoproject.com/ticket/31202, but I decided to open a new issue because I wouldn't mind waiting longer for bulk_update to complete, but the SIGTERM surprised me."	Uncategorized	new	Uncategorized	5.2	Normal				Unreviewed	0	0	0	0	0	0