[Lens] Limit operation choices based on chart type

[flash1293]

Not all operations make sense for all kinds of charts.

E.g operations which don't sum up to a meaningful total (average, median, min/max) are rarely helpful on a pie chart. This issue is meant to discuss whether we want to limit the choice of operations in some way based on the currently active chart beyond matching data types and metrics/buckets (which is already done).

I'm personally not in favor of completely disallowing these operations for two reasons:

• We allow them today so it would be a breaking change
• If the data is structured a certain way only the user can know, it's possible for these operations to be meaningful even if that's not true in the general case

My suggestion: Allow and show operations even if we don't think they are a good match for the current chart type, but highlight them and add an exemplary tooltip to make it clear that's probably not what should be used.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[wylieconlon]

I've previously considered tagging all of these functions as "summable" numbers, because they can easily and correctly be stacked or converted to a percentage. So specifically we know that Count/Sum/Cardinality can be stacked, while we can't guarantee that Avg/Min/Max/Median/Percentile can stack. I'm stuck on the wording, but do you think this is the right way of categorizing it?

I agree that we should find a way to discourage non-standard charts, while still allowing users who know what they're doing.

[markov00]

In order to provide better transparency of priorities, issues that will not be prioritized within the next 24 months are being closed.

Tracking request in Lens general improvements ice box #184459