add guidelines when to use mainQueueManagedObjectContext vs persistentStoreManagedObjectContext vs newChildManagedObjectContextWithConcurrencyType

[rodrigo-lima]

@blakewatters if you could add examples / guidelines (or in RKGist tutorial) some general rules on when to use mainQueueManagedObjectContext vs persistentStoreManagedObjectContext vs newChildManagedObjectContextWithConcurrencyType.

We have an use case where a background is loading a huge list (in chunks of 100 objects at a time), but the UI wants to render that list and also makes references to some other objects already in CoreData... when all that happens, I see deadlocks and I'm still not sure exactly what's going on.

[tplessis]

+1! I'm a bit confused with those managed object context.... :/

[blakewatters]

Will do. I am going to get 0.20.0 out the door this week and then finish out this tutorial.

[rcfrias]

Im having same confusion, I just experienced a bug where the mainQueueManageObjectContext was not saving a "Relationship" in CoreData, but the persistentStoreManagedObjectContext was. Both contexts were saving the ManagedObjects, the only difference was the "Reletions"

[thomers]

Old, but +1!

[Donnit]

Really old, but +1!

This seems to be very important for orphans deletion! Seems that RKManagedObjectRequestOperation has to deal with different context, because using mainQueueManageObjectContext local objects are the same (only filtered by fetch requests) of mapping results. This means always no orphans. And this is unreal when local db is empty!

[thomers]

Here's my +1