J.B. Langston created CASSANDRA-5947:
----------------------------------------
Summary: Sampling bug in metrics-core-2.0.3.jar used by Cassandra
Key: CASSANDRA-5947
URL: https://issues.apache.org/jira/browse/CASSANDRA-5947
Project: Cassandra
Issue Type: Bug
Reporter: J.B. Langston
There is a sampling bug in the version of the metrics library we're using in
Cassandra. See https://github.com/codahale/metrics/issues/421.
ExponentiallyDecayingSample is used by the Timer's histogram that is used in
stress tool, and according to [~brandon.williams] it is also in a few other
places like the dynamic snitch. The statistical theory involved in this bug
goes over my head so i'm not sure if this would bug would meaningfully affect
its usage by Cassandra. One of the comments on the bug mentions that it
affects slow sampling rates (10 samples/min was the example given). We're
currently distributing metrics-core-2.0.3.jar and according to the release
nodes, this bug is fixed in 2.1.3:
http://metrics.codahale.com/about/release-notes/#v2-1-3-aug-06-2012
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
