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https://issues.apache.org/jira/browse/CURATOR-447?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16308671#comment-16308671
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ASF GitHub Bot commented on CURATOR-447:
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GitHub user njhill opened a pull request:
https://github.com/apache/curator/pull/250
[CURATOR-447] TreeCache: Improve memory usage and thread safety
Jira https://issues.apache.org/jira/browse/CURATOR-374 reduced per-node
memory usage in `TreeCache`. It can be improved further via removal of the
`nodeState` field - its `LIVE` state corresponds exactly to the adjacent
`childData` field being non-null, and a sentinel `ChildData` value can be used
for the `DEAD` state. This simplification also reduces the room for bugs and
state inconsistencies.
Other improvements included:
* A further simplification to have `TreeNode` extend `AtomicReference`,
which obviates the need for an explicit `childData` field
* More robust cache update logic (in get-children and get-data event
callbacks)
* Avoid overhead of incrementing/decrementing the `outstandingOps` atomic
integer post-initialization
See corresponding JIRA:
[CURATOR-447](https://issues.apache.org/jira/browse/CURATOR-447)
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/njhill/curator CURATOR-447
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/curator/pull/250.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #250
----
commit 1c7be856fb514015286855f1ad9fd89069c32906
Author: nickhill <nickhill@...>
Date: 2017-03-26T20:19:40Z
remove nodeState field, improve thread safety of cache updates
also simplify by having TreeNode extend AtomicReference<ChildData>
commit 67210556919d7f822c431597245c4fa7246901dd
Author: nickhill <nickhill@...>
Date: 2017-03-26T20:20:32Z
avoid incrementing/decrementing outstandingOps post-initialization
no need to incur the synchronization overhead
commit a5a680d50e50a0a804caa875a53e2ee8d9a268f9
Author: nickhill <nickhill@...>
Date: 2018-01-02T16:36:20Z
remove superfluous braces
----
> TreeCache: Improve memory usage and thread safety
> -------------------------------------------------
>
> Key: CURATOR-447
> URL: https://issues.apache.org/jira/browse/CURATOR-447
> Project: Apache Curator
> Issue Type: Improvement
> Components: Recipes
> Affects Versions: 3.3.0, 2.12.0
> Reporter: Nick Hill
> Priority: Minor
> Labels: performance
>
> Jira https://issues.apache.org/jira/browse/CURATOR-374 reduced per-node
> memory usage in {{TreeCache}}. It can be improved further via removal of the
> {{nodeState}} field - its {{LIVE}} state corresponds exactly to the adjacent
> {{childData}} field being non-null, and a sentinel {{ChildData}} value can be
> used for the {{DEAD}} state. This simplification also reduces the room for
> bugs and state inconsistencies.
> Other improvements included:
> * A further simplification to have {{TreeNode}} extend {{AtomicReference}},
> which obviates the need for an explicit {{childData}} field
> * More robust cache update logic (in get-children and get-data event
> callbacks)
> * Avoid overhead of incrementing/decrementing the {{outstandingOps}} atomic
> integer post-initialization
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