CoreData writing objects slow

Question

I'm downloading list of addresses from the webservice(15.000 addresses). It took maybe 800ms to get all addresses and additional 15 seconds to write them to CoreData. Please give some advice where I am wrong:

AppDelegate *delegate = [[UIApplication sharedApplication] delegate];
            NSManagedObjectContext *managedObjectContext = delegate.managedObjectContext;
            for (NSDictionary *dict in addresses) {
                [self saveAddressesToCoreDataWithDictionary:dict andManagedObject:managedObjectContext];
            }
            [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"alreadyDownloaded"];

And method:

-(void)saveAddressesToCoreDataWithDictionary:(NSDictionary *)dict andManagedObject:(NSManagedObjectContext *)managedObject
{

    NSManagedObject *address;
    address = [NSEntityDescription insertNewObjectForEntityForName:@"Address" inManagedObjectContext:managedObject];

    [address setValue:[[dict objectForKey:@"lat"] stringValue] forKey:@"lat"];
    [address setValue:[[dict objectForKey:@"lon"] stringValue] forKey:@"lon"];
    [address setValue:[dict objectForKey:@"addressLong"] forKey:@"addressLong"];
    [address setValue:[dict objectForKey:@"addressShort"] forKey:@"addressShort"];
    NSError *error;
    [managedObject save:&error];

}

If I remember correctly, you could convert all your `NSDictionary` object into a `Address` Entity (`NSManagedObject`), and after save them all (with the `NSManagedObjectContext`) instead of saving them one by one that could take more time. You may get more info by looking for "Core Data Save Batch", like there: http://stackoverflow.com/questions/4145888/ios-coredata-batch-insert — Larme, Jul 05 '16 at 14:10
https://developer.apple.com/library/prerelease/content/documentation/Cocoa/Conceptual/CoreData/CreatingObjects.html#//apple_ref/doc/uid/TP40001075-CH5-SW4 You used the `save:` method from `NSManagedObject` where you could use the `save:` method from `NSManagedObjectContext`. Create all your `NSManagedObject`, then perform the save with the context. — Larme, Jul 05 '16 at 14:28
Yes, yes and yes!!! I saved moc everytime I iterated through this array, and it should only save once it finished itteration. — Stefan, Jul 05 '16 at 14:36

score 1 · Accepted Answer · answered Jul 05 '16 at 14:38

Figured out!

Problem was that I was saving managedObjectContext everytime, and it should be saved only when iteration is finished.

Just moved this line:

if ([managedObjectContext save:&error] == NO) {
                NSAssert(NO, @"Error saving context: %@\n%@", [error localizedDescription], [error userInfo]);
            }

below for loop.

CoreData writing objects slow

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