Concurrent operations

[jrmzlara]

Wondering on the mindset behind the implementation of concurrent object updates.

Say, more than one user update (as in save) same object at the same time. I see netbox (v3.0.1) gets the latest before the actual save. This might be a problem if same fields are updated.

[candlerb]

Netbox is built on Django, so it does what Django's ORM does.

Is there a specific scenario that's causing you concern - is it web updates through the GUI, or systems making updates via the REST API, or just all updates in general? If multiple users are frequently updating the same object in conflicting ways, then there may be a business process issue. But if that is the problem, what would you rather happen instead?

There are some third-party plugins which patch the Django ORM to perform "optimistic locking", where each object has a version number, and then the save performs a query like

UPDATE foo SET bar='baz', version=124 WHERE version=123;

This update will fail (zero rows updated) if the version number has already been changed by an overlapping request. In the case of a web UI or API request, this error would have to propagate back to the user.

In the web UI, there is data in form fields. Either these would have to be refreshed from the database (losing any data in fields which the user has changed); or the fields would be left as-is, and the user would click Save again. In the latter case, this would simply overwrite all fields of the previous update, so it wouldn't really be any different to the current situation.

[jrmzlara]

The use cases I'm thinking of are precisely those you mention (web updates through the GUI or systems making updates via the REST API).

I was thinking to implement (or, since you mentioned existing plugins; choose the best one) to get the "optimistic locking" in place and have the object fields refreshed from the database (loosing provided changes), notifying the user of what happened.

I agree that there is a business logic issue and at this time I don't see this changing anytime soon so I'd rather protect the database and message the user.

Thanks for your response!