Discarding NSManagedObjects

I create a new managed object开发者_JAVA技巧 context in a new thread an insert some objects into it. Can I discard (just forget them) them by just not saving the context? My problem is this: I start a lenghty process which creates some NSManagedObjects atthe beginning and saves them at the end (merges them back into the main store). This happens in a NSOperation. I want the user to be able to quit the app at any time without having to wait for the process to finish. Can I just kill the operation and be save? My understanding is that this is possible because the context does not persist anything without saving. Right?

Yes, you can do that but you shouldn't if the background operation handles any user data.

The UI grammar on MacOS teachers users to expect that all of their data will be saved unless they specify otherwise.

Since saving is virtually instantaneous (from the user's perspective) in the vast majority of cases, it would be better to send a notification to the background operation telling it to stop and save.