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https://issues.apache.org/jira/browse/HBASE-15160?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15257501#comment-15257501
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Yu Li commented on HBASE-15160:
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Sorry for the late response [~enis], busy resolving some online issues
recently...
bq. are you also seeing these counters get reset?
No, never observed counters reset. Also checked source of {{MutableHistogram}}
(both master and branch-1) and there should be no reset call to {{count}}.
Could you tell more details about "the histograms are reset"? Thanks.
bq. Did you try with block cache disabled
Yes, the test was against a table with BLOCKCACHE=>false. Actually, this is
part of the reason for the regression observed in HBASE-15619, you could find
more details about the test there.
bq. since even if argument pread=false, we might end up doing a pread if we
cannot get the lock
Oh yes, you are right, didn't quite notice this part... Then it's hard to
decide whether to sacrifice such accuracy for performance... Personally, maybe
I'd still choose performance.
> 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, hbase-15160_v4.patch, hbase-15160_v5.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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