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https://issues.apache.org/jira/browse/HDFS-14783?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17061031#comment-17061031
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Íñigo Goiri commented on HDFS-14783:
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[~huanghaibin] thanks for the patch.
A few comments:
* Add a javadoc to timestamp specifying what is the unit and so on (specially 
if it should be a currentTimeMillis or a nanotime with no time reference).
* This is a change in the core, so I'm not sure we should be changing the 
behavior for everybody freely. Probably enabling this as an option and just 
enable it for tested cases.
* Add a test going through the SlowPeersReport.

> Expired SampleStat needs to be removed from SlowPeersReport
> -----------------------------------------------------------
>
>                 Key: HDFS-14783
>                 URL: https://issues.apache.org/jira/browse/HDFS-14783
>             Project: Hadoop HDFS
>          Issue Type: Bug
>            Reporter: Haibin Huang
>            Assignee: Haibin Huang
>            Priority: Major
>         Attachments: HDFS-14783, HDFS-14783-001.patch, HDFS-14783-002.patch, 
> HDFS-14783-003.patch
>
>
> SlowPeersReport is calculated by the SampleStat between tow dn, so it can 
> present on nn's jmx like this:
> {code:java}
> "SlowPeersReport" :[{"SlowNode":"dn2","ReportingNodes":["dn1"]}]
> {code}
> the SampleStat is stored in a LinkedBlockingDeque<SumAndCount>, it won't be 
> removed until the queue is full and a newest one is generated. Therefore, if 
> dn1 don't send any packet to dn2 for a long time, the old SampleStat will 
> keep staying in the queue, and will be used to calculated slowpeer.I think 
> these old SampleStats should be considered as expired message and ignore them 
> when generating a new SlowPeersReport.



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