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https://issues.apache.org/jira/browse/ACCUMULO-1770?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13792726#comment-13792726
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Eric Newton commented on ACCUMULO-1770:
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The one fact that bothers me is the use of swap without a negative impact on 
performance.  It seems to me that the memory isn't being used/reused, which is 
troubling.  Also, there's not a lot of tools to help understand the usage 
patterns.

> out of memory error on very long running tablet server
> ------------------------------------------------------
>
>                 Key: ACCUMULO-1770
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-1770
>             Project: Accumulo
>          Issue Type: Bug
>          Components: tserver
>            Reporter: Eric Newton
>            Assignee: Eric Newton
>         Attachments: FragmentTest.java, memory-usage.png
>
>
> On a large cluster it was noticed that a few of the tablet servers had been 
> pushed into swap.  This didn't effect the performance of the server until it 
> ran out of memory, and the process was killed.  The gc reports in the debug 
> log showed the system had plenty of heap space for the JVM.  The number of 
> threads in the server were not excessive (dozens).  This cluster ingests some 
> large values (megabytes).  The tablet server had been up for a month prior to 
> running out of memory.  MALLOC_ARENA_MAX had already been set to 1.
> * Investigate the effect of fragmentation on memory usage for large value 
> inserts.



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