[jira] [Resolved] (CASSANDRA-8331) Expose rate of change of values in histograms

["Chris Lohfink (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-8331?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Chris Lohfink resolved CASSANDRA-8331.
--------------------------------------
    Resolution: Won't Fix

> Expose rate of change of values in histograms
> ---------------------------------------------
>
>                 Key: CASSANDRA-8331
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8331
>             Project: Cassandra
>          Issue Type: Improvement
>          Components: Core
>            Reporter: Chris Lohfink
>            Priority: Minor
>              Labels: metrics
>
> In the Metrics JMX Histograms, Sum has value for systems that want to get derivatives of the data to find rates of change.  Particularly if the timing of collection is not perfect.  The meters give some perspective to the rate of which things occur but not of the values themselves.  This could be opened up in metrics but its been shot down:
> https://github.com/dropwizard/metrics/pull/304
> I think theres still value in this. He does have point on distribution of data within the period, but in small windows with not very extreme values (ie sstables per read per second) I think its moot.  
> Alternatively we can provide Meters for each of the histograms to use its implementation of a exponentially weighted moving average to get this value.



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