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https://issues.apache.org/jira/browse/OAK-175?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13410252#comment-13410252
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Michael Dürig commented on OAK-175:
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Thanks Jukka, that's great stuff. It only solves half the problem though.
The other half is cause by {{MemoryNodeStateBuilder.snapshot}} which deeply
copies all child nodes. When adding node sequentially this leads to a quadratic
performance degradation in the number of child nodes. The solution I
implemented through {{RootImpl.purge()}} purges changes down to the branch when
the number of changes kept in memory reach a certain threshold. While this
works, I find my approach too ad-hoc and would like to come up with a more
general solution.
> MemoryNodeStateBuilder inefficient for large child node lists
> -------------------------------------------------------------
>
> Key: OAK-175
> URL: https://issues.apache.org/jira/browse/OAK-175
> Project: Jackrabbit Oak
> Issue Type: Improvement
> Components: core
> Reporter: Michael Dürig
>
> OAK-174 leverages the {{getChildBuilder()}} method introduced with OAK-170.
> This revealed a performance issue for large child node list with the
> {{MemoryNodeStateBuilder}} implementation: without additional measures (see
> below) {{RootImplTest.largeChildList()}} is very slow.
> The additional measures I currently implemented consist of counting the
> overall number of changes to a tree and purge these down to the branch when a
> certain threshold is reached. See {{RootImpl.purge()}}. However, I think this
> mechanism is too ad-hoc and we should find a more general solution.
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