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https://issues.apache.org/jira/browse/OOZIE-3232?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Andras Piros updated OOZIE-3232:
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Summary: Reduce heap waste by reducing duplicate string count (was: Oozie
may waste up to 25% of the heap due to duplicate strings)
> Reduce heap waste by reducing duplicate string count
> ----------------------------------------------------
>
> Key: OOZIE-3232
> URL: https://issues.apache.org/jira/browse/OOZIE-3232
> Project: Oozie
> Issue Type: Improvement
> Components: core
> Reporter: Misha Dmitriev
> Assignee: Misha Dmitriev
> Priority: Major
> Attachments: OOZIE-3232-01.patch, jxray-analysis-dup-strings.png
>
>
> I've recently analyzed an Oozie heap dump obtained from a customer's
> production job, using jxray (www.jxray.com). In this job, Oozie's heap
> consumption is ~6GB, and it turns out that nearly 25% of it is wasted due to
> a large number of duplicate strings. The screenshot below, taken from the
> jxray report, illustrates the problem.
> !jxray-analysis-dup-strings.png|width=638,height=669!
> It turns out that a lot of duplicate strings come from the oozie's own code,
> i.e. {{org.apache.oozie.*}}. In particular, the top data field wasting memory
> is {{org.apache.oozie.StringBlob.string}} (wastes 2.6%, or ~160MB). From the
> source code of {{StringBlob}} I see that it would be trivial to intern
> (deduplicate) these strings by adding the call to {{String.intern()}} in the
> constructor and a few other places. Similarly, various fields of
> {{org.apache.oozie.WorkflowJobBean}} and {{WorkflowActionBean}} collectively
> waste a lot of memory, and can be fixed in the same way.
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