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Asked: 2026-06-13T09:17:00+00:00

I am setting up Core Data in an application using UIManagedDocument . I am

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I am setting up Core Data in an application using UIManagedDocument. I am then adding around 1000 NSManagedObject(s) to the data base in a loop. I am initially processing the data for the objects in a background thread using:

dispatch_queue_t backgroundQueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0);
dispatch_async(backgroundQueue, ^{
    // PROCESS OBJECTS HERE
    ...
    ...

Before adding them to Core Data from the background thread:

NSManagedObjectContext *moc = [[self managedDocument] managedObjectContext];
[moc performBlock:^{
    // ADD TO CORE DATA
    ...
    ...

using:

// CREATE
Fruit *fruit = [NSEntityDescription insertNewObjectForEntityForName:@"Fruit" inManagedObjectContext:context];
// POPULATE
[fruit setName:name];
[fruit setAge:age];
[fruit setType:type];
...

My question is:

Doing the above for 1000+ objects is currently taking about 2.2secs, I am not doing any saves on Core Data until all the objects have been inserted so its all done in memory with no I/O overhead. As you can see above all my processing is done on the background thread, but when I come to insert the new object into Core Data I have to use performBlock: to make sure the insert is done back on the main thread where the UIManagedDocument was originally created.

What I would like to know is, is there a way to speed up inserting the objects, maybe by “batching” a number of NSManagedObjects together and add them in one hit, or is that just going to take the same amount of time as what I am doing now (its still adding 1000+ objects).

I did read something about creating a new context and then merging that with the NSManagedDocument context, but I am not sure if thats appropriate or how to do it if it is. Any help / information would be much appreciated.

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1 Answer

  1. Editorial Team

    1) Set the undo manager on your context to nil:

    [moc setUndoManager:nil]

    The undo information is not required if you’re never going to undo during the save.

    2) You’re already batching by adding a number of objects with a single save.

    3) Experiment with smaller batch sizes. One large save at the end can be problematic, although 1000 should be fine.

    4) You’ll also want to experiment with releasing the objects you’ve created if you change the batch size.

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