Since iOS 9 we've been reproducing these huge delay in the app processing the request back/ The app launches fine, View Controllers and everything. I'm able to interact with the app but in some cases it won't load some of all requests. It only happens in iOS9 devices (it doesn't matter if it's built against iOS8 or iOS9).
The only clue that we have is this logs repeating each time this happens:
Oct 2 15:21:15 Hurts-iPhone ondemandd[1364] <Error>: -[ODRBackgroundMaintenance startBackgroundMaintenanceOperations]
Oct 2 15:21:20 Hurts-iPhone nsurlstoraged[107] <Warning>: ERROR: NSURLStorageURLCacheDB deleteAllResponses: dbConnection=0x188dd200 DB=/private/var/mobile/Containers/Data/Application/5CD0BB06-3EF9-4A76-B5AF-25C86A8FA2AC/Library/Caches/com.company.bundleId/Cache.db Delete from cfurl_cache_blob_data failed:database is locked ErrCode: 5.
Oct 2 15:21:31 Hurts-iPhone nsurlstoraged[107] <Warning>: ERROR: NSURLStorageURLCacheDB deleteAllResponses: dbConnection=0x188dd200 DB=/private/var/mobile/Containers/Data/Application/5CD0BB06-3EF9-4A76-B5AF-25C86A8FA2AC/Library/Caches/com.company.bundleId/Cache.db Delete from cfurl_cache_receiver_data failed:database is locked ErrCode: 5.
Oct 2 15:21:31 Hurts-iPhone nsurlstoraged[107] <Error>: Error: execSQLStatement:onConnection:toCompletionWithRetry:writeLockHelp - SQL=COMMIT;, error-code=1, error-message=cannot commit - no transaction is active
Oct 2 15:21:31 Hurts-iPhone nsurlstoraged[107] <Warning>: ERROR: NSURLStorageURLCacheDB deleteAllResponses: dbConnection=0x188dd200 DB=/private/var/mobile/Containers/Data/Application/5CD0BB06-3EF9-4A76-B5AF-25C86A8FA2AC/Library/Caches/com.company.bundleId/Cache.db Commit transaction failed:cannot commit - no transaction is active ErrCode: 1.
Oct 2 15:21:34 Hurts-iPhone kernel[0] <Notice>: IOAccessoryManager::configureAllowedFeatures: tristar: revoking mask=0xffff
Oct 2 15:21:34 Hurts-iPhone iaptransportd[29] <Warning>: CIapPortAppleIDBus: Auth timer timeout completed on pAIDBPort:0x17d4a4e0, portID:01 downstream port
Oct 2 15:21:41 Hurts-iPhone nsurlstoraged[107] <Warning>: ERROR: NSURLStorageURLCacheDB deleteAllResponses: dbConnection=0x188dd200 DB=/private/var/mobile/Containers/Data/Application/5CD0BB06-3EF9-4A76-B5AF-25C86A8FA2AC/Library/Caches/com.company.bundleId/Cache.db Vacuum failed:database is locked ErrCode: 5
The only cases I've seen around with the same behavior were in Mac OS X and using native apps (Mail, iTunes, etc) which makes it even more strange.
Delaying the requests seems to alleviate these cases. It's definitely a deadlock on iOS but we'd love to get to the route of this.
I finally found a solution removing the cache from the app in the beginning. We don't make an intensive use of the app cache so, in our case, it's not an expensive solution in terms of performance. The way to remove the cache was setting an empty cache in the start of the application
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
NSURLCache *URLCache = [[NSURLCache alloc] initWithMemoryCapacity:0
diskCapacity:0
diskPath:nil];
[NSURLCache setSharedURLCache:URLCache];
I hope this helps to anyone else.
On the meantime there're some open bug reports on Apple side. When I get some more info about it I'll post it here.