[jira] [Resolved] (ACCUMULO-599) investigate permgen collection and class unloading with concurrent mark and sweep garbage collector

["Eric Newton (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ACCUMULO-599?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Eric Newton resolved ACCUMULO-599.
----------------------------------

    Resolution: Not a Problem

This may be OBE.  In Java 7, the permgen is GC'd.  Of course, you have to have all your objects deref'ed so classloaders can be removed. On larger nodes we do increase the size of the PermGen with {{-XX:MaxPermSize=512m}}. 

> investigate permgen collection and class unloading with concurrent mark and sweep garbage collector
> ---------------------------------------------------------------------------------------------------
>
>                 Key: ACCUMULO-599
>                 URL: https://issues.apache.org/jira/browse/ACCUMULO-599
>             Project: Accumulo
>          Issue Type: Bug
>          Components: scripts
>    Affects Versions: 1.3.6, 1.4.0
>            Reporter: Adam Fuchs
>            Assignee: Eric Newton
>
> The Java concurrent mark and sweep garbage collector appears to default to not unloading classes or sweeping the permgen storage space. Accumulo reloads classes dynamically, potentially contributing a lot to the permgen space. It is important that these classes be garbage collected when we're done with them. Since we use -XX:+UseConcMarkSweepGC by default for all Accumulo processes, should we also use -XX:+CMSClassUnloadingEnabled and -XX:+CMSPermGenSweepingEnabled? Are there other flags or parameters that we should set to really do java garbage collection properly in a long-lived instance?
> These should be set in conf/accumulo-env.sh as part of ACCUMULO_GENERAL_OPTS.



--
This message was sent by Atlassian JIRA
(v6.2#6252)