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
31202	Bulk update suffers from poor performance with large numbers of models and columns	Tom Forbes	Tom Forbes	"A user has reported seeing extremely slow update times when using bulk_update. With the django-bulk-update package, which does not use the expressions API and constructs raw SQL directly (https://github.com/aykut/django-bulk-update/blob/master/django_bulk_update/helper.py#L202), an update with 100,000 objects and and 10 fields takes 24 seconds. With the built in bulk_update it takes 2 minutes and 24 seconds - 6x as slow.

The user has provided a reproduction case here: https://github.com/mikicz/bulk-update-tests/blob/master/apps/something/models.py and https://github.com/mikicz/bulk-update-tests/blob/master/apps/something/test_bulk_update.py

From an initial look at the profiling that has been provided (https://github.com/aykut/django-bulk-update/files/4060369/inbuilt_pyinstrument.txt) it seems a lot of overhead comes from building the SQL query rather than executing it - I think if we can improve the performance it could speed up other workloads.

See: https://github.com/aykut/django-bulk-update/issues/75#issuecomment-576886385"	Cleanup/optimization	assigned	Database layer (models, ORM)	dev	Normal			Mikuláš Poul Florian Demmer John Speno Akash Kumar Sen Jacob Walls	Accepted	0	0	0	0	0	0