thetaSketch metrics are missing percentage

[dejan]

Hi, first of all thanks for all your work on amazing tool Turnilo!

I've noticed thetaSketch metrics are missing % Percent selection in Turnilo.

Is there some limitation for this, or is it just a bug? Is there a workaround perhaphs that can be done in the configuration for example?

[adrianmroz-allegro]

Hi!

It is intentional. Theta sketches are approximations and any numerical operation on approximated value would increase error margin. Because percents are calculated in post-transformation it would give very inaccurate results.

Same story with "calculate".

[dejan]

Theta sketches are approximations and any numerical operation on approximated value would increase error margin.

Does this mean splits would not add up to 100% for example, or that percentages would not follow estimates ratio? Or both? Or something else?

[dejan]

I've tested this by adding the percentage component in the UI.

The problem that splits don't add up to 100% of total is present, but that's also true for absolute numbers. The ratio of error with the absolute number seems to be the same - so I'm not seeing increased error margin (or can it happen only in certian situation?).

Here's an example I've used:

Both colums add up to 0.9974499570660391 of the total. Both should add up to 1 if those were exact metrics.

For "calculate", maybe it makes sense to keep it disabled, as it would allow to combine approximated and exact metrics. But for "percentage", the operation is always on approximated values, so the behaviour is expected and consistent (estimates are wrong on the same level).

To summarize: maybe you can reconsider enabling "percentage" for approximated metrics.