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https://issues.apache.org/jira/browse/CASSANDRA-1024?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ryan King updated CASSANDRA-1024:
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Attachment: 1024.patch
This is w WIP patch. Current it does:
* keeps estimated histograms on a geometric scale from 1 microsecond to around
30 seconds (each bucket is 1.2 larger than the previous)
* exposes read and write latency histograms for each CF (not sure if this is
the best way)
TODO:
* recent histograms
* deal with some concurrency issues (should probably use AtomicLongArray's)
* percentiles (export useful percentiles (25, 50, 75, 90, 99, 99.9, etc))
> Latency Histograms
> ------------------
>
> Key: CASSANDRA-1024
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1024
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Ryan King
> Assignee: Ryan King
> Attachments: 1024.patch
>
>
> In addition to total and recent latency, I would like to keep track of
> histograms. We have a way for doing estimated histograms (whose error domain
> gets worse the higher the latency and whose storage requirements are
> constant). It works pretty well for us:
>
> http://github.com/robey/ostrich/blob/master/src/main/scala/com/twitter/ostrich/Histogram.scala
> I'm planning on doing the work, but wanted to know if it would be useful to
> others.
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