Chris Burroughs created CASSANDRA-11752:
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Summary: 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
Attachments: boost-metrics.png, c-jconsole-comparison.png,
c-metrics.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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