Re: Versioning and CoreData
Re: Versioning and CoreData
- Subject: Re: Versioning and CoreData
- From: Ryan Britton <email@hidden>
- Date: Sat, 6 May 2006 08:35:44 -0700
On May 6, 2006, at 7:04 AM, Uli Kusterer wrote:
There is one other limitation that I didn't mention here. Store
size plays a factor. This currently does no batching so large
store sizes may not be practical without adding some kind of
batching functionality. My data sets have been small so I've not
done anything like this.
What do you mean by "batching functionality"? You mean that doing
the conversion to a new model would require loading and writing out
of the entire store, and one would ideally try to load only a few
objects at a time, or what?
Something like that, yes. If you're working with a store that has
50000 objects or some huge number, it may not be practical to do the
entire conversion with the store in memory. It would need some kind
of support to be able to do all of those objects in small batches so
that the memory could be reclaimed at each iteration rather than
ballooning (one useful trick I've found for this kind of thing is to
have a field in the model called "conversion" that you write the old
object ID into on the new, migrated object -- this lets you keep
track of all of the pairings using the store itself instead of
keeping some huge list). As it stands now though, I have not had a
store that would grow this large so I haven't done anything about it.
Ryan
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