Transformations: Add regression analysis transformation

[oscarkilhed]

What is this feature?

This adds a transformation that fits a mathematical function to X/Y data.

Typically this can be used on time series to get a trend line.

Which issue(s) does this PR fix?:

Fixes #7812
Fixes #73441

Special notes for your reviewer:

Todo:

• Add tests.
• Add descriptive image.
• Figure out a name for the transformation.
• Docs.

Please check that:

• It works as expected from a user's perspective.
• If this is a pre-GA feature, it is behind a feature toggle.
• The docs are updated, and if this is a notable improvement, it's added to our What's New doc.

[oscarkilhed]

/deploy-to-hg

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[baldm0mma]

Possible issue with Data frames...

[imatwawana]

Thanks for the update! I've left one question which should be resolved before you merge, but otherwise, this looks fine to me.

[imatwawana]

What are you referring to when you use the word "mode" here? The two models above or the whole Regression analysis transformation? If the former, then we should use "model"; if the latter then we should use "transformation". It's not clear what you mean.

[oscarkilhed]

Ah, thank you. This refers the the transformation as a whole. Have changed the note to reflect that.

[baldm0mma]

Go home git, you're drunk.

[oscarkilhed]

Go home git, you're drunk.

I believe this is the commit hook auto formatting spaces to tabs

[3ricj]

I'm really excited about this feature -- it seems to be included in 10.3, which is what I just updated to. However, I seem unable to find how to use it or turn it on or enable it. I've been looking for documentation to assist, without any luck so far. Help?

[whizkidTRW]

Same here! Following for updates.

[mcpherrinm]

The documentation is in the PR you're commenting on, and visible at https://grafana.com/docs/grafana/latest/panels-visualizations/query-transform-data/transform-data/#regression-analysis

Notably, you'll need to turn a feature toggle on.

[whizkidTRW]

Ah, excellent! The only thing I see now is that in my implementation, I have network graphs where there's an In data rate and an Out data rate (Negative-Y) and I'd like to show a trendline for both. Is there any way to name both regressions uniquely?

I tried adding two regressions and set them both to Polynomial (which works perfectly!) but the Organize fields by name transformation only sees one field instead of two since they're named the same. Can it derive from the Y field possibly?

[oscarkilhed]

@whizkidTRW Hmm, it should be named after the y field: https://github.com/grafana/grafana/blob/main/public/app/features/transformers/regression/regression.ts#L111

Not sure why yours are named value. Open an issue and follow the guide on how to attach the panel data and I can take a look.

[whizkidTRW]

Done! #81317

Let me know if you need more data or examples, I'm happy to share as I really look forward to using this feature.

Thanks!

[oscarkilhed]

Should be fixed with this PR: #81332

[whizkidTRW]

Excellent. Thank you! I look forward to trying this out.