Core Data vs Sqlite and performance

Question

I am wondering if anyone has any real world numbers on performance differences between an old sqlite application which has been converted to Core Data in the 3.0 SDK.

I suspect that under the hood Core Data is just using sqlite anyways and that it add's a bit of overhead for the cost of convenience, but i thought i would ask anyways.

• Mike Abdullah: There's no need to "suspect" this. It's very clearly stated in the documentation that you have the option of a SQLite store.

Answer 1

Core Data is heavily optimized with regards to caching, lazy-loading and memory management.

If you use it (with the SQLite store type), especially in conjunction with NSFetchedResultsController, you should get better performance than you could get with SQLite on your own.

Apple has worked hard to make Core Data perform well on the iPhone. My application switched from SQLite w/ FMDB to Core Data and it is now faster and more stable with less code.

• Brad Larson: I was of the common impression that Core Data would just add overhead to SQLite, but I was shown that everything you describe is true. In fact, I believe the iPhone's address book is now based on Core Data in 3.0. That's a pretty strong vote of confidence.
• Hunter: I believe the iPod app now is as well.
• RyBolt: thanks for a great answer, backed by personal experience vs. theoretical type jargon.

Answer 2

Core Data can use sqllite - it is up to the developer to configure - so your suspect correctly. On the Phone I would suggest sqllite is the best idea.

I think one of the biggest benefits you can gain by using Core Data is the lazy loading of data and the faulting to save on memory. So you need to also think about things like this when you are considering performance as the amount of free memory you have will also impact performance.