iOS 10: Major NSFetchedResultsController Slowdown After an Object is Updated

Hello,


`We are seeing an unclear major performance slowdown. While the database is static, performance is good. Then, after an object is updated and the fetched restuls controller is updated, we start seeing a major slowdown. What we noticed using `-com.apple.CoreData.SQLDebug 1`, is that when calling the `fetchedObjects` method cause the fetched results controller to iterate over all objects and fulfil them. Our design was based on using `fetchedObjects` as the source of our collection view (rather than `objectAtIndexPath:`). Everything works correctly as long as objects are static and are not updated.


I do not see any documented change for how NSFetchedResultsController operates.


This issue does not exist in iOS 9.x. The issue reproduces for us under iOS 10 with the app both build against SDK 9 or SDK 10.


Please assist.

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Leo Natan
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I just encountered exactly the same issue and not sure how to proceed... Did you find more info on this issue?

Posted by
Yoash
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Seeing this as well, was this a change of behavior in iOS 10?

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eddiekim
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Yes, I think that this is a new behavior of iOS 10 since it doesn't reproduce with iOS 8 and iOS 9.


I assume that this is a new bug in iOS 10 not yet fixed by Apple. Could any one tell if a related bug was submitted to Apple bug report system? Also, it would be greatly appreciated if an Apple engineer can reply with some feedback...

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Yoash
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