[jira] [Commented] (HADOOP-10839) Add unregisterSource() to MetricsSystem API

["shanyu zhao (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HADOOP-10839?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14062748#comment-14062748 ] 

shanyu zhao commented on HADOOP-10839:
--------------------------------------

Hi [~cnauroth] Thanks for the review!

I pulled from trunk in github before I generate the patch so it should be against the current trunk...

Regarding the unusual indentation, I was just trying to use the same indentation in that file. If you look at other methods in the same file, it all has the way I wrote in the patch. Do you think I need to modify the indentation to what you proposed above? That's more normal way but would seem odd I in that source code file.

> Add unregisterSource() to MetricsSystem API
> -------------------------------------------
>
>                 Key: HADOOP-10839
>                 URL: https://issues.apache.org/jira/browse/HADOOP-10839
>             Project: Hadoop Common
>          Issue Type: Bug
>          Components: metrics
>    Affects Versions: 2.4.1
>            Reporter: shanyu zhao
>            Assignee: shanyu zhao
>         Attachments: HADOOP-10839.patch
>
>
> Currently the MetrisSystem API has register() method to register a MetricsSource but doesn't have unregister() method. This means once a MetricsSource is registered with the MetricsSystem, it will be there forever until the MetricsSystem is shut down. This in some cases can cause Java OutOfMemoryError.
> One such case is in file system metrics implementation. The new AbstractFileSystem/FileContext framework does not implement a cache so every file system access can lead to the creation of a NativeFileSystem instance. (refer to HADOOP-6356). And all these NativeFileSystem needs to share the same instance of MetricsSystemImpl, which means we cannot shut down MetricsSystem to clean up all the MetricsSources that has been registered but no longer active. Over time the MetricsSource instance accumulates and eventually we saw OutOfMemoryError.



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