NSFetchRequest with fetchOffset doesn't return expected results

Question

I've encountered something strange when trying to get "paged" entities from Core Data.

Here is the code I use for fetching:

NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"User" 
                                          inManagedObjectContext:self.managedObjectContext];
fetchRequest.predicate = [NSPredicate predicateWithFormat:@"userIdentifier beginswith[cd] %@ AND selected == 1",userIdentifier];
fetchRequest.fetchOffset = offset;
fetchRequest.fetchLimit = limit;
[fetchRequest setEntity:entity];
NSLog(@"offset %d limit %d",fetchRequest.fetchOffset,fetchRequest.fetchLimit);

NSError *requestError = nil;
NSArray *items = [self.managedObjectContext executeFetchRequest:fetchRequest
                                                          error:&requestError];
NSLog(@"fetched items count = %d",items.count);

And here are the logs:

2013-01-31 16:01:28.127 offset 0 limit 100
2013-01-31 16:01:28.128 fetched items count = 6
2013-01-31 16:01:40.533 offset 1 limit 100
2013-01-31 16:01:40.535 fetched items count = 5
2013-01-31 16:01:53.029 offset 2 limit 100
2013-01-31 16:01:53.032 fetched items count = 4
2013-01-31 16:01:55.468 offset 3 limit 100
2013-01-31 16:01:55.470 fetched items count = 3
2013-01-31 16:02:00.776 offset 4 limit 100
2013-01-31 16:02:00.779 fetched items count = 2
2013-01-31 16:02:02.325 offset 5 limit 100
2013-01-31 16:02:02.328 fetched items count = 1
2013-01-31 16:02:03.837 offset 6 limit 100
2013-01-31 16:02:03.839 fetched items count = 0
2013-01-31 16:02:07.714 offset 6 limit 100
2013-01-31 16:02:07.717 fetched items count = 0

For this test I had 6 entries for "User".

What am I doing wrong?

Thanks

Answer 1

Your logs indicate that everything is working as expected.

Congratulations!