Aggregate values to show "per time period"?

#1

I have an eventsource posting values to NodeRED. I want to show some metrics in a dashboard:

  • Events per minute for the last hour
  • Events per hour for the last day
  • Average value (each event comes with a measurement) per minute/hour

What’s a good way to aggregate? Would I use the context/flow/global object for that or something else?

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#2

How about saving them to a database and aggregate from the database?

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#3

Thx for the reply. Appreciate the time taken.
Database is the plan B. Though for just a few values (60 & 24) in memory would do (and would be fast).
Also found this: https://flows.nodered.org/node/node-red-contrib-aggregator
Seem to do the trick

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#4

This ode you pointed seems to do something very similar to the standard palette smooth node, I don’t know what is the difference.

If you wanted to make something really easy you can do it with a simple counter and reset every hour or at a specific time, (maybe having various running) however this will give you the messages since a specific time, for instance since 00:00 or since 13:00 or whatever, not exactly latest 60 minutes.

Regards

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#5

FYI - I have raised following feature request : https://github.com/jaggr2/node-red-contrib-aggregator/issues/10
for node-red-contrib-aggregator

Once implemented, this should give an even more real time view of the running average or running total over a configurable period.

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#6

In case the messages are arriving at fixed rate (e.g. once every 10 seconds) then node-red-node-smooth can be used.

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