[Lens] It displays empty legends values with filtered metrics

[shahzad31]

In lens, if you do filtering (filtered metric) and breakdown on same field in lens, it displays legends values only for filtered metrics but in legends it displays all legends values from breakdown field

example screenshot

[elasticmachine]

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

[flash1293]

This is happening because the "top values" function doesn't "know" about the applied filter and is determining terms by looking at the full set of documents.

I don't see a straight-forward fix here:

• Filtering terms as well doesn't always work as there might be other metrics which are not filtered / filtered by something else
• Having a filter on the terms agg itself instead of the individual metric seems confusing
• Filtering the legend in the chart is brittle - e.g. for the count or sum metrics, the values are 0 instead of null. Not sure whether "filter all series which are always 0 or null/undefined" would work in all situations

[flash1293]

We discussed this and decided to not implement a quick-fix for this scenario because it's an edge case and adding a new high level concept / setting will add more complexity than justified. Once we implement #86190 , this can be solved in a nice way.