Github user njhill commented on the issue:
https://github.com/apache/curator/pull/250
Thanks @dragonsinth, there's of course no rush at all!
I agree that `TreeNode extends AtomicReference` isn't a "win" as such, it
just looked cleaner to me than using another `AtomicReferenceFieldUpdater`. But
it's likely subjective and certainly a minor thing.
The `outstandingOps` change seems clearer to me - the field has no use for
most of the life of the cache and yet is incremented/decremented on every
single change. It's not the CPU cycle overhead but more the (CPU) cache
coherency overhead since it's an `AtomicLong`. I didn't think the change
introduces any raciness - the only times when `outstandingOps` needs to be
modified (during initialization or re-initialization) it will be guaranteed to
be non-null.
> I would expect the memory footprint of `ConcurrentMap<String, TreeNode>`
children to mostly dominate the memory overhead of our own classes
Good point. The description of
[CURATOR-374](https://issues.apache.org/jira/browse/CURATOR-374) implied this
might have _some_ mem overhead benefit for very large caches, but removal of
the `nodeState` field was motivated more by state simplification and
consolidation of atomic updates. I'll do some quick measurements but I
acknowledge percentage-wise the saving might not be significant.
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