On Jan 13, 2012, at 3:45 PM, Chris Hanson wrote: > On Jan 13, 2012, at 12:39 AM, Michael Link wrote: > >> the docs seem to indicate that using a main thread concurrency type MOC on >> the main thread without performBlock: is fine. > > It is, otherwise you couldn't (say) bind to a managed object you fetched via > a main-queue context on OS X. What OS version(s) are you seeing this with?
iOS 5.0 on simulator and iOS 5.0.1 on iPhone. > >> It appears that the private queue is waiting on the PSCs lock which the >> child context on the main thread has already locked. It appears that the >> child context (while holding the PSCs lock) is trying to dispatch_sync to >> the parent context and thus they are both waiting for each other. >> >> Is PriveQueue -> MainQueue a supported configuration? It seems most people >> still have the parent context on the main thread. > > Using a parent private-queue context and a child main-queue context is > actually a good design. I'm not sure about your deadlock; does it still > occur if you don't use -performBlock: on your main-queue context but just > interact with it directly? Yes, in exactly the same way. I'm starting to think the problem is with NSFetchedResultsController which is always stuck at performFetch: when these deadlocks occur. Most of the time it will be stuck trying to fault in an object as a result of asking for it's section name. As a test I tried to reproduce what the FRC does and performed the executeFetchRequest: and then iterated through the results asking each object for it's section name. And this doesn't cause a deadlock. If I leave the FRC to do performFetch: after I do my test it will still deadlock there. I'm 99% sure that the FRC has a synchronization problem with nested contexts. -- Michael_______________________________________________ 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 arch...@mail-archive.com
