Multiple NSManagedObjectContexts in one expression NSPersistentStoreCoordinator throws 'still active' exception

Question

I am changing the CoreData setting to 2 NSManagedObjectContextbelow 1 NSPersistentStoreCoordinator.

• The root context NSManagedObjectContext created with NSPrivateQueueConcurrencyTypeand setNSMergeByPropertyStoreTrumpMergePolicy
• The main context NSManagedObjectContext created by using NSMainQueueConcurrencyTypeis also set toNSMergeByPropertyStoreTrumpMergePolicy

Both of them are not related by the parent-child relationship, but they are assigned the same object NSPersistentStoreCoordinator. The main context listens for the Root Context notification NSManagedObjectContextDidSaveNotificationand performs the necessary merge insideperformBlock:

Sometimes, when an instance is NSFetchedResultsControllerconnected to the Main Context , does performFetchI get

The application terminated due to the uncaught exception "NSInternalInconsistencyException", reason: "the instruction is still active"

I am wondering if I need to do what I am doing here or the Core Data limitation.

thanks

Answer 1

Florian Kugler wrote a good article about this: Parallel Main Data Stack

The idea is to import your data in the context of a private queue ( Import Context ), which is a child of the Main Context .

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