MeasurementUnits (EPOCH_MILLISECONDS, EPOCH_SECONDS)

Elias Ross genman at noderunner.net
Thu Sep 20 16:37:41 UTC 2012


I'll respond here and maybe Bugzilla.

My particular use case is this metric:

      <metric property="hbaseLastProcessDate"
              dataType="measurement"
              description="HBase last processing date"
              units="epoch_milliseconds"/>

I have a component that loads data periodically (say, every minute),
but regularly into HBase. This metric tracks the last time data was
completely loaded. I get this from parsing an actual string from a
file, e.g.:

'201209122216'

As a trait, the value would change very frequently. RHQ would store a
new value for the trait, as a String, every time the metric was
polled.

But as a measurement, RHQ would instead store a 'double'. Storing as a
metric allows for a few different things as well:

1. Change formatting depending on the browser & user local time zone.
2. See trending. Ideally, the 'last time' would increase at a steady rate.
3. Alarm if the value does not change.
4. Alarm if the value is, say, 1 hour ago and the threshold is 10 minutes.

Alternatively, the metric could be defined as a relative time value:

      <metric property="hbaseLastProcessSecondsAgo"
              dataType="measurement"
              description="For HBase, how many seconds ago was the
data processed"
              units="seconds"/>

I don't really mind switching to relative time, but it seems
reasonable to support this in the UI.


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