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PODoes AFIncrementalStore need an NSMainQueueConcurrencyType context?
 

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  1. PODoes AFIncrementalStore need an NSMainQueueConcurrencyType context?
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    <p>I've been working on incorporating AFIncrementalStore into our app following the example code in the repository that uses an <code>SQLite</code> backing store. All the examples use a singleton managedObjectContext with an <code>NSMainQueueConcurrencyType</code>. </p> <pre><code>+ (NSManagedObjectContext *)managedObjectContext { static NSManagedObjectContext *_managedObjectContext = nil; static dispatch_once_t onceToken; dispatch_once(&amp;onceToken, ^{ NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { _managedObjectContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType]; [_managedObjectContext setPersistentStoreCoordinator:coordinator]; } }); return _managedObjectContext; } </code></pre> <p>Using this moc, I'm able to perform a fetch, see it get pulled from the network, and stored in the sqlite backing store. I tried changing it to use the <code>NSPrivateQueueConcurrencyType</code>, and while I would see the network request, nothing was ever saved to the <code>SQLite</code> backing store. However, if I leave this moc with main queue concurrency, and then create a child from it, and use <em>that</em> moc, then everything saves fine. </p> <pre><code>+ (User *)user { // grab a user if we already have one NSManagedObjectContext *managedObjectContext = [VigilCoreDatabase managedObjectContext]; NSManagedObjectContext *tmpContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSPrivateQueueConcurrencyType]; tmpContext.parentContext = managedObjectContext; NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init]; fetchRequest.fetchLimit = 1; [fetchRequest setAffectedStores:@[ ]]; NSEntityDescription *entity = [NSEntityDescription entityForName:@"User" inManagedObjectContext:tmpContext]; [fetchRequest setEntity:entity]; __block User *user = nil; [tmpContext performBlockAndWait:^{ NSError *error = nil; NSArray *fetchedObjects = [tmpContext executeFetchRequest:fetchRequest error:&amp;error]; if (fetchedObjects == nil) { NSLog(@"error"); } if(fetchedObjects.count &gt; 0) { user = fetchedObjects[0]; } }]; return user; } </code></pre> <p>I wanted to figure out if I was missing something in my understanding. I can't seem to find any examples that don't use a moc with main queue concurrency as the parent context (with the backing store using a private queue context), but at the same time can't find any documentation explaining whether this is required, or whether I need to do something to push changes to the parent manually when using a private queue context vs. having a main queue context in the stack.</p>
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