[Lens] Filter last value fields by default

[ghudgins]

Describe the feature:
When selecting the last value function in Lens (top_hits) we should auto apply a fieldname : * filter to the metric / field so that it returns a value if one is present.

Describe a specific use case for the feature:
Given A user is using a data view that has multiple indexes in it (or multiple event.datasets like non data stream beats)
When a user picks "Last Value" + a field
I need the default metric to come out with an "exists" filter on it
So I can avoid the confusion of last value returning a - even though there was a true last value in the interval

[elasticmachine]

Pinging @elastic/kibana-vis-editors (Team:VisEditors)

[flash1293]

I can definitely see the case for this, it's annoying to fall into this trap ("why are some last values empty?"). Some questions:

• Should it be visible and changeable to the user or should we change the semantics of "last value" to "last existing value" as a whole? Not sure about it, it might be taking away too much control
• How would transitions work? I guess if the field is changed, then the filter is changed to the new field as long as it was <old field name>: * before, otherwise it just keeps the filter the user defined

[ghudgins]

I was thinking it could just be applied (and removed by the user if they want) as a default post setting a new field.

yeah on the transition on clear if it's the exists filter for a previous field (if possible)

[ghudgins]

+1 from observability metrics explorer

[ghudgins]

+1

I have gone into dashboard visualise and created a table with host name and latest value option for the above indexes, but they appear as dashes

from https://discuss.elastic.co/t/visualising/289212

[ghudgins]

I need show on dashboard uptime for server. I tried do this by Lens -> Metric. When i set for metric: Last value od system.uptime.duration.ms and sort by @timestamp then i dont see anything. In index i have this data, i can see this in Discovery modul. When i switch in metric from 'Last value' to Mediana then data was showed. Why i cant see this when i have choosen Last value ?

+1 from https://discuss.elastic.co/t/last-value-of-syste-uptime-duration-ms/298119

[ghudgins]

+1 https://discuss.elastic.co/t/last-value-no-result-found/297981

hi my field having new value every min, i want to show the latest value of field in Metric regardless of dashboard Time interval but when i choose Last value i got No result found