objective c - Core Data Fault

Question

I am mapping Json Data from Server using Restkit and I am Displaying those data by fetching from db. There is a refresh button in my view which performs the above operation again.

Scenario: I have two tables Key & Profile which has one-one relationship. I am fetching data from DB using follwing code

NSFetchRequest *fetchRequest = [Key fetchRequest];
[fetchRequest setRelationshipKeyPathsForPrefetching:[NSArray arrayWithObject:@"Profile"]];
[fetchRequest setIncludesSubentities:YES];
NSArray *sortedObjects = [Key executeFetchRequest:fetchRequest]; 

Above array returns all object in DB. but when i check that using breakpoint, i got some core data fault which was the reason for not showing all the data.

//All data in sortedObjects are like this.

<Key: 0x889f2f0> (entity: Key; id: 0x889e400 <x-coredata://981A476D-55AC-4CB4-BBD8-E0285E522412/Key/p1489> ; data: <fault>)

Any idea

Answer 1

This might be a misunderstanding about what a 'fault' is.

As described in Apple's documentation:

Faulting is a mechanism Core Data employs to reduce your application’s memory usage.

and

A fault is a placeholder object that represents a managed object that has not yet been fully realized, or a collection object that represents a relationship:

So, if you see the word 'fault' in logs when you're working with Core Data, it doesn't mean that an error has occurred. What unexpected behaviour are you seeing in your app?