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

["Misha Dmitriev (JIRA)" <ji...@apache.org>]

Misha Dmitriev created OOZIE-3232:
-------------------------------------

             Summary: 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: Misha Dmitriev
         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!

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.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)