Open
Description
Proposal:
Variables should allow for selecting a specific value as well as all values.
Case:
User creates a dashboard and wants the dashboard to show data for all values of a certain Tag (say, host) so that any grouping queries can visualize each Tag in the same context, distinguished from one another. However, they may also want to view a dashboard for a single Tag value.
Current behavior:
The above case only works in the following two ways:
- create two dashboards -- one with queries that contain
group(columns: [<tag>]and one with queries that contain afilter()on the variable's selected value. Creating two dashboards for this, alone, is a pain. - hack a
*option into each variable you define. This is currently a hack that requires defining a variable with a join operation on two datasets; one that generates a table with a single*value and one that generates the independent values you want. This makes the variable, itself, non-performant. It also adds to user costs. And is an incredibly difficult solution for a user to come by on their own volition. An example of the variable query that is required to achieve this:
import "influxdata/influxdb/v1"
all_data = buckets() |> limit(n:1) |> set(key: "_value", value: "*") |> keep(columns:["_value"])
hosts = v1.measurementTagValues(bucket: "sam's Bucket", measurement: "cpu", tag: "host")
union(tables: [all_data, hosts]) |> sort()
Desired behavior:
A query that filters by a variable value AND groups by the Tag would take either the "all" or "individual" cases into account.
I'm also told that adding a grouping operation onto a single value is negligible extra query overhead.