`nodetool cfhistogram` utility script
Hi, I just quickly put together a tiny utility script to estimate average/mean/min/max/percentiles for `nodetool cfhistogram` latency output. Maybe could be useful to someone else, don’t know. You can find it here: https://gist.github.com/JensRantil/3da67e39f50aaf4f5bce Future improvements would obviously be to not hardcode `us:` and support the other histograms. Also, this logic should maybe even be moved into the `nodetool cfhistogram` since these are fairly common metrics for latency. Cheers, Jens ——— Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter
Re: `nodetool cfhistogram` utility script
Hey Jens, Unfortunately the output of the nodetool histograms changes between versions. While I think your script is useful, it's likely to break between versions. You might be interested to weigh in on the JIRA ticket to make the nodetool output machine friendly: https://issues.apache.org/jira/browse/CASSANDRA-5977 On Fri Dec 12 2014 at 5:48:51 AM Jens Rantil jens.ran...@tink.se wrote: Hi, I just quickly put together a tiny utility script to estimate average/mean/min/max/percentiles for `nodetool cfhistogram` latency output. Maybe could be useful to someone else, don’t know. You can find it here: https://gist.github.com/JensRantil/3da67e39f50aaf4f5bce Future improvements would obviously be to not hardcode `us:` and support the other histograms. Also, this logic should maybe even be moved into the `nodetool cfhistogram` since these are fairly common metrics for latency. Cheers, Jens ——— Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter
Re: `nodetool cfhistogram` utility script
You can also collect these stats from the server via JMX, I believe the name of the MBean object is org.apache.cassandra.metrics:type=ColumnFamily,keyspace=KEYSPACE,scope=SCOPE,name=SSTablesPerReadHistogram where KEYSPACE is your keyspace and SCOPE is Read or Write. This has attributes for 50thPercentile, 75th, 99th etc. On Dec 12, 2014, at 8:48 AM, Jens Rantil jens.ran...@tink.se wrote: Hi, I just quickly put together a tiny utility script to estimate average/mean/min/max/percentiles for `nodetool cfhistogram` latency output. Maybe could be useful to someone else, don’t know. You can find it here: https://gist.github.com/JensRantil/3da67e39f50aaf4f5bce Future improvements would obviously be to not hardcode `us:` and support the other histograms. Also, this logic should maybe even be moved into the `nodetool cfhistogram` since these are fairly common metrics for latency. Cheers, Jens ——— Jens Rantil Backend engineer Tink AB Email: jens.ran...@tink.se Phone: +46 708 84 18 32 Web: www.tink.se Facebook Linkedin Twitter
