[jira] [Assigned] (OOZIE-3232) Oozie may waste up to 25% of the heap due to duplicate strings

["Peter Cseh (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/OOZIE-3232?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Peter Cseh reassigned OOZIE-3232:
---------------------------------

    Assignee: Peter Cseh  (was: Misha Dmitriev)

> Oozie may waste up to 25% of the heap due to duplicate strings
> --------------------------------------------------------------
>
>                 Key: OOZIE-3232
>                 URL: https://issues.apache.org/jira/browse/OOZIE-3232
>             Project: Oozie
>          Issue Type: Improvement
>          Components: core
>            Reporter: Misha Dmitriev
>            Assignee: Peter Cseh
>            Priority: Major
>         Attachments: 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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