[jira] [Comment Edited] (CASSANDRA-11752) histograms/metrics in 2.2 do not appear recency biased

["T Jake Luciani (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-11752?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15281526#comment-15281526 ] 

T Jake Luciani edited comment on CASSANDRA-11752 at 5/12/16 1:47 PM:
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I see your point [~cburroughs]  there is value to both (correctness vs recency)  

If there is no way to diff it in graphite we could perhaps do this  server side. 
  Keep a snapshot of the histogram for the last 5 min and add them.




was (Author: tjake):
I see your point [~cburroughs]  there is value to both (correctness vs recency)  

If there is no way to diff it in graphite we could perhaps do this  server side. 
  Keep a snapshot of the histogram for the last 5 min and add diff them.



> histograms/metrics in 2.2 do not appear recency biased
> ------------------------------------------------------
>
>                 Key: CASSANDRA-11752
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-11752
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Chris Burroughs
>              Labels: metrics
>         Attachments: boost-metrics.png, c-jconsole-comparison.png, c-metrics.png, default-histogram.png
>
>
> In addition to upgrading to metrics3, CASSANDRA-5657 switched to using  a custom histogram implementation.  After upgrading to Cassandra 2.2 histograms/timer metrics are not suspiciously flat.  To be useful for graphing and alerting metrics need to be biased towards recent events.
> I have attached images that I think illustrate this.
>  * The first two are a comparison between latency observed by a C* 2.2 (us) cluster shoring very flat lines and a client (using metrics 2.2.0, ms) showing server performance problems.  We can't rule out with total certainty that something else isn't the cause (that's why we measure from both the client & server) but they very rarely disagree.
>  * The 3rd image compares jconsole viewing of metrics on a 2.2 and 2.1 cluster over several minutes.  Not a single digit changed on the 2.2 cluster.



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