The Big Nerd Ranch Core Data Stack
Robert Edwards notes that the Nested Managed Object Context Pattern has some cons:
- Slower than Shared Persistent Store Coordinator Pattern when inserting large data sets
awakeFromInsertbeing called onNSManagedObjectsubclasses for each context in the parent chain- Merge policies only apply to a context saving to a store and not to its parent context
[…]
Since saving an
NSManagedObjectContextwill only propagate changes up a single level to theparentContext, the Big Nerd Ranch Core Data Stack listens for save notifications and ensures that the changes get persisted all the way up the chain to your store.You may sometimes need to perform large import operations where the nested context performance would be the bottleneck. For that, we’ve included a function to vend you a managed object context with its own stack
newBatchOperationContext(setupCallback: CoreDataStackBatchMOCCallback). This follows the pattern outlined in Shared Store Stack Pattern.
