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https://issues.apache.org/jira/browse/JCR-3721?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13889394#comment-13889394
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Maxim Zinal commented on JCR-3721:
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NodeId.toString() is called from
org.apache.jackrabbit.core.query.lucene.ChildAxisQuery.SimpleChildrenCalculator.getHits()
method. It is used to create search term to locate child node in lucene index.
AFAICS SimpleChildrenCalculator.getHits() method is called for every XPath
hierarchy-based query, and I was not able to avoid all these toString() calls,
because Apache Lucene 3.6 uses java String type as a basis for search Terms.
> Slow and actively called NodeId.toString()
> ------------------------------------------
>
> Key: JCR-3721
> URL: https://issues.apache.org/jira/browse/JCR-3721
> Project: Jackrabbit Content Repository
> Issue Type: Bug
> Components: jackrabbit-core
> Affects Versions: 2.6.5, 2.7
> Environment: Debian/GNU Linux 7.3 / Oracle JDK 7 / Apache Tomcat 7.0;
> Windows Server 2008 / IBM WebSphere AppServer 7.0
> Reporter: Maxim Zinal
> Attachments: NodeIdToString.patch
>
>
> I performed some JackRabbit profiling while trying to investigate the reason
> of low performance of our application.
> The mostly interesting thing I've found is that NodeId.toString() method is
> heavily used for hierarchy-based XPath queries, and it performs really bad.
> This are the numbers for my test application:
> - Total CPU time: 879 178 msec
> - CPU time in NodeId.toString(), including subcalls: 223 705 msec
> A quick check against NodeId.toString() implementation shows that it is based
> on UUID.toString(), which itself is very ineffective in both in Oracle and
> IBM JDK.
> I've wrote a quick replacement for this method, and my measurements show that
> overall performance became significantly better for our case.
> Hope that this will help to improve JackRabbit performance for similiar
> applications.
> P.S. Another interesting thing I've found is that a lot of time is spent
> inside log4j.Category.getEffectiveLevel() method - I suspect this is caused
> by numerous log.debug() calls without proper isDebugEnabled() handling.
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