Async'ly fetch requests on CoreData

gistfile1.txt

// assume self.managedObjectContext is a main queue context
NSManagedObjectContext *backgroundContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType];
[backgroundContext performBlock:^{
    // do your fetch - e.g. executeFetchRequest
    NSManagedObjectID *objID = [someManagedObject objectID];
    [self.managedObjectContext performBlock:^{
        NSManagedObject *mainManagedObject = [self.managedObjectContext objectWithID:objID];
        //  do something now with this managed object in the main context
    }];
}];