Using rabbitmq metrics as an example, thee are metric constructs the follow this pattern:

...where metrics are published per-"channel" but where individual channel metrics aren't particularly useful. With promql (NB - i am not a Prometheus expert), it's trivial to sum(some_series, where some_label="foo" and some_label="bar") across a series such as this, but in this case, channel represents an object which can be ephemeral, so indexing on the channel name would cause the rrds & resources to grow unbounded.

It would be helpful for this use-case if the config could be extended to allow us to aggregate an entire series into a single metric at collection-time, optionally by label.