Question

Here’s my code, which is taking some JSON data and inserting it into the Core Data room entity:

for (NSDictionary *room in rooms)
    {
        NSDictionary *thisroom = [room objectForKey:@"room"];
        NSString *roomidstring = [thisroom objectForKey:@"roomid"];
        int roomid = [roomidstring intValue];
        NSString *roomname = [thisroom objectForKey:@"roomname"];
        NSString *buildingidstring = [thisroom objectForKey:@"buildingid"];
        int buildingid = [buildingidstring intValue];

        // import into database
        NSManagedObject *roomInfo = [NSEntityDescription insertNewObjectForEntityForName:@"room" inManagedObjectContext:context];
        [roomInfo setValue:[NSNumber numberWithInteger:roomid] forKey:@"roomid"];
        [roomInfo setValue:roomname forKey:@"roomname"];
        [roomInfo setValue:[NSNumber numberWithInteger:buildingid] forKey:@"buildingid"];
         if (![context save:&error]) {
            NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
        }
    }

It is incredibly slow when inserting around 900 objects. Is there any way to make this more efficient and/or to speed it up?

Thanks!

Answer 1

Yes there is, DO NOT save until you finish the loop, or save in batches if memory is an issue. The save operation is very expensive so you should avoid saving often in tight loops like this one.

for (NSDictionary *room in rooms)
{
    NSDictionary *thisroom = [room objectForKey:@"room"];
    NSString *roomidstring = [thisroom objectForKey:@"roomid"];
    int roomid = [roomidstring intValue];
    NSString *roomname = [thisroom objectForKey:@"roomname"];
    NSString *buildingidstring = [thisroom objectForKey:@"buildingid"];
    int buildingid = [buildingidstring intValue];

    // import into database
    NSManagedObject *roomInfo = [NSEntityDescription insertNewObjectForEntityForName:@"room" inManagedObjectContext:context];
    [roomInfo setValue:[NSNumber numberWithInteger:roomid] forKey:@"roomid"];
    [roomInfo setValue:roomname forKey:@"roomname"];
    [roomInfo setValue:[NSNumber numberWithInteger:buildingid] forKey:@"buildingid"];
}


if (![context save:&error]) {
     NSLog(@"Whoops, couldn't save: %@", [error localizedDescription]);
}