iOS optimal performance persistent data solution?

Question

I am building a healthKit based app and am wondering how to best save healthKit data persistently.

My current approach is to get the data and save it as attributes of a custom class object and then save it in core data as NSData.

In terms of performance is Realm faster than CoreData?

According to http://qiita.com/moriyaman/items/1a2916f4c2b79e934370 CoreData is apparently slower than FMDB which is slower than Realm. Can someone confirm if this is true even after taking into account faults and indexes?

Answer 1

Disclaimer: I work at Realm

The question of which persistence product will perform best among the solutions you mentioned is highly dependent on the type/amount/frequency of your data. Since Core Data and FMDB are layers over SQLite, they can't be faster than SQLite by design, but they provide enough convenience to be worthwhile to many users. On the other hand, Realm isn't based on SQLite, but rather its own custom database engine that was designed specifically for modern smartphones. It was designed to strike a better balance between powerful features, simple API without adding a large performance hit.

You can see public benchmarks comparing Realm/SQLite/Core Data/FMDB in Realm's launch blog post here: http://realm.io/news/introducing-realm#fast

Finally, your approach of serializing HealthKit information into NSData using something like NSCoding is going to be terribly inefficient. No matter the persistence solution you choose, you'll be better served by using the serialization built in to those products rather than storing an already serialized data blob.