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https://issues.apache.org/jira/browse/LANG-1229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15284932#comment-15284932
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Philippe Marschall commented on LANG-1229:
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A potential patch https://github.com/apache/commons-lang/pull/142
> Performance regression due to cyclic hashCode guard
> ---------------------------------------------------
>
> Key: LANG-1229
> URL: https://issues.apache.org/jira/browse/LANG-1229
> Project: Commons Lang
> Issue Type: Bug
> Components: lang.builder.*
> Affects Versions: 3.5
> Reporter: Philippe Marschall
>
> We observed a severe performance regression in HashCodeBuilder in 3.5 trunk
> compared to 3.4 release. We get about 20% of the throughput in 3.5 trunk for
> common cases compared to 3.4 release. Previously there was no noticeable
> overhead of using HashCodeBuilder. Investigating we found the performance
> degradation was caused by the fix for LANG-456. It causes the method to be
> too large to be inlined and escape analysis to fail (see LANG-1218 for a
> related discussion).
> We currently do not see a way to keep the 3.4 performance and support cyclic
> graphs. The append methods have not supported cycles for so long we feel it's
> de facto part of the contract by now. Since neither the JDK nor the Guava
> hashCode helper methods support cyclic graphs we don't believe this is an
> unreasonable assumption. In addition EqualsBuilder#append(Object,Object)
> doesn't support cycles.
> If supporting cycles is a requirement we propose the introduction of new
> #appendRecursive (or named differently) methods to both HashCodeBuilder and
> EqualsBuilder that add cycle guards. If that is an acceptable compromise we
> would be willing to provide patches.
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