Helm's Flow datasource cannot filter "NaN" results, breaking Grafana reduce expressions

Description

The OpenNMS Flows API inserts "NaN" for any cell in the result set that doesn't have a value.
Grafana's reduce expressions will always return "NaN" if any values are null or NaN.

Expected result:
Helm should provide a way to filter "NaN" from the results returned by OpenNMS, so reducing expressions can be applied to them.

Actual result:
Any data set that includes "NaN" cannot be reduced.

Could add a nonNull() query transform, similar to the groupByInterval() one.

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  • 06 Mar 2022, 11:37 PM
  • 06 Mar 2022, 01:34 PM

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Alberto March 29, 2022 at 2:09 PM

Fixed parsing "NaN" as null

Included a new Transform function to convert NaN to Zero

Updated documentation

Merged to develop

Will Keaney March 6, 2022 at 11:18 PM

The Grafana-provided filters are not useful with the Helm plugin's Flow datasource.

Will Keaney March 6, 2022 at 11:17 PM
Edited

Yes, but that feature only allows filtering by conversation key in the Helm plugin.
Given that we have thousands of locations, 500k devices, and potentially millions of conversation keys, that's hardly practical.

Alberto March 6, 2022 at 1:35 PM

Grafana 7.4+ includes this feature already.

Alberto March 6, 2022 at 1:34 PM

Since Grafana 7.4 there is a new Transformation "Filter Data by Values" where this can be achieved.

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Alberto

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Created January 28, 2022 at 7:54 PM
Updated September 8, 2022 at 5:08 PM
Resolved March 29, 2022 at 2:09 PM

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