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PONSManagedObjectContext deadlocking from 2 serial queues
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copied!<p>I've created a system where i can request an NSManagedObjectContext from a singleton object, dependant on the queue it's running on. Every serial GCD dispatch queue is associated with a certain task, and thus gets its own context, though all with the same persistent store coordinator.</p> <p>I was under the assumption that this would solve my problems associated with threads, which it so far seems to have done, but now i have a different problem: If 2 serial queues, with different MOCs, both try to make the context execute, they both lock and the app freezes. So what did i miss?</p> <p>"...[I]f you create one context per thread, but all pointing to the same persistent store coordinator, Core Data takes care of accessing the coordinator in a thread-safe way (the lock and unlock methods of NSManagedObjectContext handle recursion)." (<a href="http://developer.apple.com/library/ios/#documentation/cocoa/conceptual/CoreData/Articles/cdConcurrency.html" rel="nofollow">source</a>)</p> <p>What i read there, is that Core Data should handle locking and unlocking correctly with my setup. Or do i understand 'in a thread-safe way' wrong in this case?</p> <p>Edit: I basically have a dictionary that maps a queue to a context. At first i wanted to work with threads instead of queues, until i read this part:</p> <p>"Note: You can use threads, serial operation queues, or dispatch queues for concurrency. For the sake of conciseness, this article uses “thread” throughout to refer to any of these." (<a href="http://developer.apple.com/library/ios/#documentation/cocoa/conceptual/CoreData/Articles/cdConcurrency.html" rel="nofollow">source</a>)</p>

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