Robert Joseph Evans created STORM-2610:
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Summary: Spout throttelign metrics are unusable
Key: STORM-2610
URL: https://issues.apache.org/jira/browse/STORM-2610
Project: Apache Storm
Issue Type: New Feature
Components: storm-client, storm-core
Affects Versions: 1.0.0, 2.0.0
Reporter: Robert Joseph Evans
Assignee: Robert Joseph Evans
When helping someone debug an issue with backpressure I realized that the
metrics we are collecting in the spout are mistakenly being multiplied by the
rate, even though we are not sub-sampling them. This results in the values
being, by default, 20 times higher then they should be. Thinking about how I
would use the metrics to debug an issue also showed that some of them.
skipped-max-spout and skipped-throttle correspond to about 1 ms of sleep, but
skipped-inactive corresponds to about 100 ms of sleep. And the 1 ms sleep is
configurable so it could be different from one topology to another, and even
the code around it is pluggable, so it could be doing anything from not
sleeping to sleeping a random amount of time.
I think we just need to scrap what we have been doing and record how long we
sleep for and use that as the metric instead.
These metrics also don't appear to be documented anywhere so I am going to
change what they mean and document them to actually be useful, and correct.
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