[APM] Latency correlations: Always display at least one correlated term

[peteharverson]

In the Latency correlations tab, we currently hide all results where the correlation is considered to be very low. However this means users who wait for the analysis to complete can often end up seeing "No results". To improve the user experience here, we should always show at least one result, but if necessary label it as very low.

Similarly, we should also identify whether it is always possible to show at least one correlated term in the Failed transactions tab.

[elasticmachine]

Pinging @elastic/ml-ui (:ml)

[elasticmachine]

Pinging @elastic/apm-ui (Team:apm)

[formgeist]

Just bringing over @sophiec20's comment from a related issue:

[...] We propose to display at least one result with a v low badge. This would be the only item in the table with nothing to compare it to, so benefits from a literal badge.

I agree that it would be great to reduce the wait time to get any results, but isn't it misleading when adding an insignificant correlation value or one with "very low" impact? I imagine the user expects the view to filter out all the noise and only present values that are significant enough to investigate. In this case, the user will instinctively react to the results first served and possible not even stay around for the following values that actually might have valuable correlations.

Am I missing something?

[sophiec20]

The motivation of this request is to improve handing of the "No correlations" experience. The motivation is not in order to show quicker results.

The cut off point between low and very low is based on statistical analysis of representative data. It is data dependent, so it's not an absolute yes/no decision.

Suppose the environment is moderately sized and this calculation takes 20 seconds to run. From a users perspective, it would be preferable to see some v low correlations, rather than nothing - after having waited 20 secs, say.

We trust that the user, who sees the literal badge saying v low, is able to decide if they investigate further - just like we trust them to make a similar decision if the correlation is low. This can be implemented only if no other HML correlations are found.

[formgeist]

The motivation of this request is to improve handing of the "No correlations" experience. The motivation is not in order to show quicker results.

Thanks for clarifying - then I definitely misunderstood what the proposal was about. I fully support the motivation for showing results in the table 👍

[peteharverson]

Closing as addressed for 8.2.0 by #126683.