What I'm doing wrong? Polystat transformations

[sur1v]

• What Grafana version and what operating system are you using?

9.5.2 @ Debian

• What are you trying to achieve?

Display the metric difference change % using dynamic interval

• How are you trying to achieve it?

Using transformations after querying the first and last metrics of the interval

• What happened?

Is not showing the expected values, way less

• What did you expect to happen?

Metric should be in the order of 1% to 3%

• Can you copy/paste the configuration(s) that you are having problems with?

Added in a screenshot

• Did you receive any errors in the Grafana UI or in related logs? If so, please tell us exactly what they were.

No

• Did you follow any online instructions? If so, what is the URL?

Official grafana doc

[sur1v]

[yosiasz]

Check this function out

spread() function | Flux 0.x Documentation

[sur1v]

Thanks for that @yosiasz, I have created the polystat using the described function, however the numbers still wrong. I suspect of problems with the interval, the following is 24h and should be around 3% of difference.

[yosiasz]

Did you fully read the spread function documentation?

spread() returns the difference between the minimum and maximum values in a specified column.

[sur1v]

I think I did @yosiasz, is just one line anyway, and I think is working as expected. I’m having issues with the interval, I want it to be dynamic using the dashboard time range, could you check the screenshot attached in my previous message please?

[yosiasz]

Remove everything else and leave the spread query. It does all of it

[sur1v]

Thanks @yosiasz but is not working at all. Do you mind to explain why the spread difference will work as percentage? Not documented.

[sur1v]

Solution was fairly easy, just grab first and last metric and do the math, no function needed at all.

[yosiasz]

Works indeed but performance wise this is costly as you are hitting the back end twice.
And you are indeed using 2 functions first and last .

With spread you do it once and then apply the percentage math.

[sur1v]

Thanks @yosiasz, but math wont work in line with the time range as explained before, main need is to be dynamic metric, also is not handling negative differences. Both issues remains unsolved.