On Mar 29, 2008, at 11:48 PM, Jeff LaMarche wrote:
Are you using separate managed object contexts for each thread?
According to the documentation here:
http://developer.apple.com/documentation/Cocoa/Conceptual/CoreData/
Articles/cdMultiThreading.html
That's the way to do it - pass managed object IDs between threads,
not managed objects, and when you're done, you can call
refreshObject:mergeChanges: on the main thread's context with the
objects that were changed, then call processPendingChanges on it.
He stated that using the 1 MOC/thread scheme doesn't work for his
situation since in doing so you have to save: whenever you want to
sync the MOCs in different threads. I'm actually interested in this
question as I just rewrote a chunk of my app to do things the 1 MOC/
thread way and have seen pretty crappy performance due to all the
saving. My UI is slightly more responsive but particularly on older
(tiger) machines it really pegs the processor and disk with having to
save so much and the actually task takes significantly longer. The
other issue is that when you spawn a new thread/MOC you have to build
out any of the object graph that you'll need. In my case that is a
couple thousand objects and contributes to the performance hit as well.
So, the question still stands, is there a way to use CoreData driven
bindings in a multithreaded app with a single managed object
context? Anyone?
->Ben
--
Ben Lachman
Acacia Tree Software
http://acaciatreesoftware.com
[EMAIL PROTECTED]
740.590.0009
On Mar 29, 2008, at 11:30 PM, David wrote:
I would think this is the normal typical case, but can't figure it
out.
The UI should run on one thread, another thread should be used for
time
consuming updates/generation of an object tree maintained using
Core Data. I
have a NSOutlineView (via NSTreeController subclass) which
displays the
object tree from Core data.
I can not figure out how to make this thread safe. I periodically
get random
data showing up in the outline view while the core data object
tree is being
updated.
I've tried locking the managedObjectContext when I make additions
or changes
to the object tree, but I still get erroneous data showing up in
the view.
I don't understand how NSTreeController and bindings are
interacting with
Core data to extract the data while I'm populating it.
Any suggestions greatly appreciated.
I've been reading and rereading the Core Data programming guide and
Threading programming guide to no avail.
The Core data programming guide says its best to maintain a separate
managedObjectContext per thread. But this appears to require the
data to be
written to persistent store to make it work (file). That not
reasonable in
my case where I'm adding many objects to an object tree. It takes a
significant amount to time to write it out, negating the benefit
of trying
to make the UI seem responsive.
I'm running Leopard.
_______________________________________________
Cocoa-dev mailing list (Cocoa-dev@lists.apple.com)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com
This email sent to [EMAIL PROTECTED]
