[jboss-dev-forums] [Design of JBossCache] - Re: Optimistic locking doesn't scale well with large 'flat'

[jason.greene@jboss.com]

"manik.surtani at jboss.com" wrote :   trying to get a child node will cache a null in the workspace if the child node doesn't exist - to maintain repeatable_read
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Technically we don't have to do this, repeatable read allows phantoms, and they are still possible if the lazy loading occurs after a new child is created.

anonymous wrote : 
  | The drawback here is that it allows for s slight difference in semantics from pessimistic locking, due to the lazy locking (copying into workspace) of children .
  | 

I don't think there is a difference here. Pessimistic locking already allows phantoms by not forcing a write lock when nodes are added/remove. 

anonymous wrote : 
  | Is this approach workable?

Yes, another option is to just lazy copy the entire map the first time it is actually read.

-Jason

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