NSFetchedResultsController loads the whole data and bad performance - ios

Question

I have a large database with over 8000 entries in it. I want to load and list in tableview. I used NSFetchedResultsController. It's working fine except the bad performance. I found the tutorial here
And added my performFetch: method in the viewDidLoad: method. But it takes 2-3 seconds to load the view.
Here it is my code.
- (void)loadFetchResultsController {
NSError *error;
if (![[self fetchedResultsController] performFetch:&error]) {
// Update to handle the error appropriately.
NSLog(#"Error occurs while fetching the foods with fetch results controller %#, %#", error, [error userInfo]);
exit(-1);
}
}
- (NSFetchedResultsController *)fetchedResultsController
{
if (isSearching)
{
[NSFetchedResultsController deleteCacheWithName:#"SearchResults"];
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription
entityForName:#"Food" inManagedObjectContext:_managedObjectContext];
NSPredicate *hiddenPredicate = [NSPredicate predicateWithFormat:#"hidden == %#",[NSNumber numberWithBool:NO]];
if (isSearching)
{
hiddenPredicate = [NSPredicate predicateWithFormat:#"(hidden == %#) AND (name contains[cd] %# OR foodDescription contains[cd] %#)",[NSNumber numberWithBool:NO], searchTerm,searchTerm];
}
[fetchRequest setEntity:entity];
[fetchRequest setPredicate:hiddenPredicate];
NSSortDescriptor *sort = [[NSSortDescriptor alloc]
initWithKey:#"name" ascending:YES];
[fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];
[fetchRequest setFetchBatchSize:20];
NSFetchedResultsController *theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:_managedObjectContext sectionNameKeyPath:#"name.stringGroupByFirstInitial" cacheName:(isSearching) ? #"SearchResults" : #"Root"];
_fetchedResultsController = theFetchedResultsController;
_fetchedResultsController.delegate = self;
return _fetchedResultsController;
}
I used the instruments and found out that calling performFetch: method loads the whole data for the first time when viewDidLoad: calls.
My food data model is like this:
Any idea to improve the performance and get rid of delay.. Any help would be appreciated.

Answer 1

I believe you need to set the fetch limit on your fetch request, not just the batch size. Try calling [fetchRequest setFetchLimit:20]; and see if that helps. This should cause the first 20 records to be fetched. Then as the user scrolls through your data, make additional fetch requests to get more data.