a table view with 2 FRCs as data sources sharing a context and pointing to the same data with different predicates

gistfile1.m

#import "MasterViewController.h"

#import "DetailViewController.h"

#import "Event.h"
#import "NSManagedObject+utils.h"

@interface MasterViewController ()
{
    NSUInteger _updatingTable;
}
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath;
@end

@implementation MasterViewController

- (void)awakeFromNib
{
    self.clearsSelectionOnViewWillAppear = NO;
    self.preferredContentSize = CGSizeMake(320.0, 600.0);
    [super awakeFromNib];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
	// Do any additional setup after loading the view, typically from a nib.
    self.navigationItem.leftBarButtonItem = self.editButtonItem;

    UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)];
    self.navigationItem.rightBarButtonItem = addButton;
    self.detailViewController = (DetailViewController *)[[self.splitViewController.viewControllers lastObject] topViewController];
    id x = self.mainFetchedResultsController;
    x = self.filteredFetchedResultsController;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)insertNewObject:(id)sender
{
    NSManagedObjectContext *context = [self managedObjectContext];
    [Event createWithConfigBlock:^(Event *obj, NSUInteger index) {
        obj.n =@(rand()%2);
        obj.name = [NSString stringWithFormat:@"%i%i%i",rand()%10,rand()%10,rand()%10];
    } context:context];
   NSError *error = nil;
    if (![context save:&error]) {
         // Replace this implementation with code to handle the error appropriately.
         // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
}

#pragma mark - Table View

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return 2;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    NSFetchedResultsController* controller = (section ? self.mainFetchedResultsController : self.filteredFetchedResultsController);
    id <NSFetchedResultsSectionInfo> sectionInfo = [controller sections][0];
    return [sectionInfo numberOfObjects];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    [self configureCell:cell atIndexPath:indexPath];
    return cell;
}

- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Return NO if you do not want the specified item to be editable.
    return YES;
}

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        NSManagedObjectContext *context = self.managedObjectContext;
        [context deleteObject:[self objectAtIndexPath:indexPath]];
        
        NSError *error = nil;
        if (![context save:&error]) {
             // Replace this implementation with code to handle the error appropriately.
             // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            abort();
        }
    }   
}

- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
    // The table view should not be re-orderable.
    return NO;
}

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSManagedObject *object = [self objectAtIndexPath:indexPath];
    self.detailViewController.detailItem = object;
}

- (NSFetchedResultsController*) fetchedResultsController:(NSIndexPath*)indexPath
{
    if (indexPath.section == 1) {
        return self.mainFetchedResultsController;
    }
    return self.filteredFetchedResultsController;
}

- (NSManagedObject*) objectAtIndexPath:(NSIndexPath*)indexPath
{
    NSFetchedResultsController* controller = [self fetchedResultsController:indexPath];
    NSIndexPath* newIndexPath = [NSIndexPath indexPathForRow:indexPath.row inSection:0];
    return [controller objectAtIndexPath:newIndexPath];
}

#pragma mark - Fetched results controller

- (NSFetchedResultsController *) mainFetchedResultsController
{
    if (_mainFetchedResultsController != nil) {
        return _mainFetchedResultsController;
    }
    
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"n == 0 OR n == 1"]];
    [fetchRequest setEntity:entity];
    
    // Set the batch size to a suitable number.
    [fetchRequest setFetchBatchSize:20];
    
    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO];
    NSArray *sortDescriptors = @[sortDescriptor];
    
    [fetchRequest setSortDescriptors:sortDescriptors];
    
    // Edit the section name key path and cache name if appropriate.
    // nil for section name key path means "no sections".
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
    aFetchedResultsController.delegate = self;
    self.mainFetchedResultsController = aFetchedResultsController;
    
	NSError *error = nil;
	if (![self.mainFetchedResultsController performFetch:&error]) {
	     // Replace this implementation with code to handle the error appropriately.
	     // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
	    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
	    abort();
	}
    
    return _mainFetchedResultsController;
}

- (NSFetchedResultsController*) filteredFetchedResultsController
{
    if (_filteredFetchedResultsController != nil) {
        return _filteredFetchedResultsController;
    }
    
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    // Edit the entity name as appropriate.
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setPredicate:[NSPredicate predicateWithFormat:@"n == 0"]];
    [fetchRequest setEntity:entity];
    
    // Set the batch size to a suitable number.
    [fetchRequest setFetchBatchSize:20];
    
    // Edit the sort key as appropriate.
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:NO];
    NSArray *sortDescriptors = @[sortDescriptor];
    
    [fetchRequest setSortDescriptors:sortDescriptors];
    
    // Edit the section name key path and cache name if appropriate.
    // nil for section name key path means "no sections".
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
    aFetchedResultsController.delegate = self;
    self.filteredFetchedResultsController = aFetchedResultsController;
    
	NSError *error = nil;
	if (![self.filteredFetchedResultsController performFetch:&error]) {
        // Replace this implementation with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
	    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
	    abort();
	}
    
    return _filteredFetchedResultsController;

}

- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
    if (_updatingTable == 0) {
        [self.tableView beginUpdates];
    }
    _updatingTable++;
}

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
       atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
      newIndexPath:(NSIndexPath *)newIndexPath
{
    UITableView *tableView = self.tableView;
    
    if (controller != self.filteredFetchedResultsController) {
        indexPath = [NSIndexPath indexPathForRow:indexPath.row inSection:1];
        if (newIndexPath) {
            newIndexPath = [NSIndexPath indexPathForRow:newIndexPath.row inSection:1];
        }
    }
    
    switch(type) {
        case NSFetchedResultsChangeInsert:
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
            
        case NSFetchedResultsChangeDelete:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
            
        case NSFetchedResultsChangeUpdate:
            [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            break;
            
        case NSFetchedResultsChangeMove:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
    }
}

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
    _updatingTable--;
    if (_updatingTable == 0) {
        [self.tableView endUpdates];
    }
}

/*
// Implementing the above methods to update the table view in response to individual changes may have performance implications if a large number of changes are made simultaneously. If this proves to be an issue, you can instead just implement controllerDidChangeContent: which notifies the delegate that all section and object changes have been processed. 
 
 - (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
    // In the simplest, most efficient, case, reload the table view.
    [self.tableView reloadData];
}
 */

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
    NSManagedObject *object = [self objectAtIndexPath:indexPath];
    cell.textLabel.text = [NSString stringWithFormat:@"%@-%@",[object valueForKey:@"name"],[object valueForKey:@"n"]];
}

@end

Very helpful. This is just what I was looking for. Thanks for posting!