[jira] [Commented] (HBASE-15160) Put back HFile's HDFS op latency sampling code and add metrics for monitoring

["Yu Li (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-15160?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15239224#comment-15239224 ] 

Yu Li commented on HBASE-15160:
-------------------------------

Back to this JIRA. Confirmed that under heavy random read(get) load, the current patch using BlockingQueue to collect metrics will cause *~3%* performance regression. Benchmarking with the JMH case Enis wrote up we could see using MutableHistogram is less expensive thus promising. Will re-implement with MutableHistogram and see how it works out.

[~enis], mind if I take this one back? Or you already have something in progress? Thanks.

> Put back HFile's HDFS op latency sampling code and add metrics for monitoring
> -----------------------------------------------------------------------------
>
>                 Key: HBASE-15160
>                 URL: https://issues.apache.org/jira/browse/HBASE-15160
>             Project: HBase
>          Issue Type: Sub-task
>    Affects Versions: 2.0.0, 1.1.2
>            Reporter: Yu Li
>            Assignee: Yu Li
>         Attachments: HBASE-15160.patch, HBASE-15160_v2.patch, HBASE-15160_v3.patch
>
>
> In HBASE-11586 all HDFS op latency sampling code, including fsReadLatency, fsPreadLatency and fsWriteLatency, have been removed. There was some discussion about putting them back in a new JIRA but never happened. According to our experience, these metrics are useful to judge whether issue lies on HDFS when slow request occurs, so we propose to put them back in this JIRA, and add the metrics for monitoring as well.



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