[
https://issues.apache.org/jira/browse/CASSANDRA-6591?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13921078#comment-13921078
]
Yuki Morishita commented on CASSANDRA-6591:
-------------------------------------------
My test is here https://gist.github.com/yukim/9371796 which simulates misses
after hits.
If I plot this to graph:
!https://docs.google.com/spreadsheet/oimg?key=0AhjS79jizSXtdDJUcnBzdU9tSG9WVG5ia1N3eUx1bnc&oid=5&zx=xnsjrj3s0of0!
The blue line is the one proposed in this ticket and the red line is "hit rate"
one minute rate, and I see quite difference there.
> un-deprecate cache recentHitRate and expose in o.a.c.metrics
> ------------------------------------------------------------
>
> Key: CASSANDRA-6591
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6591
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Chris Burroughs
> Assignee: Chris Burroughs
> Priority: Minor
> Attachments: j6591-1.2-v1.txt, j6591-1.2-v2.txt, j6591-1.2-v3.txt
>
>
> recentHitRate metrics were not added as part of CASSANDRA-4009 because there
> is not an obvious way to do it with the Metrics library. Instead hitRate was
> added as an all time measurement since node restart.
> This does allow changes in cache rate (aka production performance problems)
> to be detected. Ideally there would be 1/5/15 moving averages for the hit
> rate, but I'm not sure how to calculate that. Instead I propose updating
> recentHitRate on a fixed interval and exposing that as a Gauge.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
