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From Philipp Bussche <philipp.buss...@gmail.com>
Subject Sink metric numRecordsIn drops temporarily
Date Sun, 17 Sep 2017 13:17:48 GMT
Hi there, I witnessed an interesting behaviour on my Grafana dashboard where
sink related metrics would show activity where there should not be any. I am
saying this because for this particular sink activity is triggered by data
being ingested through a cronjob at a particular time, however the dashboard
is saying there is activity also outside this time.
I had a closer look and in my graph I am using the NonNegativeDerivative
function (the data actually sits in Graphite) on the metric. Disabling this
filter shows that for a short period of time the numRecordsIn counter is
dropping and then gets back to the previous value. This drop is then shown
on the graph and is looking like data activity because of the
NonNegativeDerivative function.
Why would the value of a counter temporarily decrease and then go back to
its previous level ?
Please see screenshots attached.

Thanks
Philipp

<http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/file/t576/Sink_numRecordsIn_NonNegativeDerivative_.png>

<http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/file/t576/Sink_numRecordsIn_Value_Drops.png>




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