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https://issues.apache.org/jira/browse/JCR-2699?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12919265#action_12919265
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Ian Boston commented on JCR-2699:
---------------------------------
The AccessControlProviderHolder attached here does put more pressure on the
Heap than before and we have seen it result in high GC levels as it extracts
all the space it can out of the JVM under heavy load (100 concurrent request
threads). There is an updated version being maintained at
http://github.com/ieb/open-experiments/blob/master/bundles/server/src/main/java/org/apache/jackrabbit/core/AccessControlProviderHolder.java
(for the record ASF License granted), this uses soft references and a
reference queue to allow the GC to evict SystemSessions when under pressure,
although I found that this still put the GC under undue pressure so it also
explicitly evicts AccessControlProviders when they get old and full ensuring
that heap is never overloaded. Teste with Jmeter scripts over several hours.
Will make a brief comment on JCR-2573
> Improve read/write concurrency
> ------------------------------
>
> Key: JCR-2699
> URL: https://issues.apache.org/jira/browse/JCR-2699
> Project: Jackrabbit Content Repository
> Issue Type: Improvement
> Components: jackrabbit-core
> Reporter: Jukka Zitting
> Assignee: Jukka Zitting
> Fix For: 2.2.0
>
> Attachments: AccessControlProviderHolder.java,
> ConcurrentReadTest.png, ConcurrentReadTest.png, ConcurrentReadWriteTest.png,
> DynamicSecurityManager-JCR2699.patch
>
>
> I'd like to set up a few performance tests to help identify our worst
> bottlenecks for various kinds of concurrent read-only and read-write access
> patterns.
> Once identified, I'm hoping to fix at least some of those bottlenecks.
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