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https://issues.apache.org/jira/browse/CASSANDRA-18305?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17736203#comment-17736203
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Brad Schoening commented on CASSANDRA-18305:
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[~smiklosovic] I suggested these rate metrics because they are some of the very
few JMX compaction metrics available. They're the best approximation of a trend
line we have, but I agree, they're not all that useful.
The mean rate is since the server started, and I could see comparing the
current rate to the mean could be somewhat useful.
It would be much better to have the Meter measure compaction throughput in
Mbps. Especially since that value has a throttle in the cassandra.yaml.
[~brandon.williams] why was it difficult to have compaction throughput (Mbps)
as a JMX Meter?
Normalizing the values to minutes would be good. It's per/sec only because
that's what a Dropwizard Meter measures. Given the skimpy metrics we have,
having just a) mean and b)15 minute rate reported per/minute.
> Enhance nodetool compactionstats with existing MBean metrics
> ------------------------------------------------------------
>
> Key: CASSANDRA-18305
> URL: https://issues.apache.org/jira/browse/CASSANDRA-18305
> Project: Cassandra
> Issue Type: Improvement
> Components: Tool/nodetool
> Reporter: Brad Schoening
> Assignee: Manish Ghildiyal
> Priority: Normal
> Fix For: 4.0.x, 4.1.x, 5.x
>
> Time Spent: 3h 10m
> Remaining Estimate: 0h
>
> Nodetool compactionstats reports only on active compactions, if nothing is
> active, you see only:
> {quote}$nodetool compactionstats
> pending tasks: 0
> {quote}
> but in the MBean Compaction/TotalCompactionsCompleted there are recent
> statistic in events/second for:
> * Count
> * FifteenMinueRate
> * FiveMinueRate
> * MeanRate
> * OneMinuteRate
> 1) It would be useful to see in addition:
> {quote}pending tasks: 0
> compactions completed: 20
> 1 minute rate: 0/second
> 5 minute rate: 2.3/second
> 15 minute rate: 4.6/second
> {quote}
> 2) Since compaction_throughput_mb_per_sec is a throttling parameter in
> cassandra.yaml (default 64 MBps), it would be nice to show the actual
> compaction throughput and be able to observe if you're close to the limit.
> I.e.,
> {quote}compaction throughput 13.2 MBps / 16 MBps (82.5%)
> {quote}
> 3) for completness, compactionstats should list the number of concurrent
> compactors configured, perhaps simply add to existing 'pending tasks' line:
> {quote}4 concurrent compactors, 0 pending tasks
> {quote}
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