Get rid of slow event updates in delete_inventory

[AlanCoding]

Please confirm the following

• I agree to follow this project's code of conduct.
• I have checked the current issues for duplicates.
• I understand that AWX is open source software provided for free and that I might not receive a timely response.

Feature type

New Feature

Feature Summary

We should delete these lines because they can become a very slow query, and have no restrictions for the event partition they operate on.

awx/awx/main/tasks/system.py

Lines 843 to 844 in b8c48f7

	for host in i.hosts.iterator():
	host.job_events_as_primary_host.update(host=None)

Because the Event.host ForeignKey already is set to DO_NOTHING on_delete, it should work fine.

This issue requests:

• develop a patch to delete that loop
• develop minimal testing to assure the job events API still works after deleting an inventory that has hosts with associated events

Select the relevant components

• UI
• API
• Docs
• Collection
• CLI
• Other

Steps to reproduce

Not a bug, just slow query elimination.

Current results

Query can go slow.

Sugested feature result

Do not do that query at all.

Additional information

No response

[AlanCoding]

I think the most recent related work was #12447

This converted the host ForeignKey from SET_NULL to DO_NOTHING. At the point that happened, deleting this bit should have been possible. @john-westcott-iv do you know of any reason that was not done at that time? Any blockers for doing it now?

[AlanCoding]

change has merged