Core Data concurrency `performBlockAndWait:` NSManagedObjectContext zombie

Question

I have a following crash report from my released app:

synchronizeMyWords method fetches the entities from database, creates private queue context w

Answer 1

Core Data provides ample APIs to deal with background threads. These are also accessible via Magical Record.

It looks as if you creating too many threads unnecessarily. I think that the employment of AWSContinuationBlock and AWSExecutor is not a good idea. synchronizeMyWords could be called from a background thread. The block might be run on a background thread. Inside the block you create a new background thread linked to the child context. It is not clear what loadLocalWords returns, or how continueWithExecutor:block: deals with threads.

There is also a problem with the saving of the data. The main context is not saved after the child context is saved; presumably this happens later, but perhaps in connection with some other operation, so that the fact that your code was working before is perhaps more of a "false positive".

My recommendation is to simplify the threading code. You should confine yourself to the Core Data block APIs.