Subtracting histogram buckets returns "No datapoints found."

[elerer]

What did you do?

dns_latency_bucket{le="30.0"} - dns_latency_bucket{le="10.0"}

What did you expect to see?

The per bucket count i.e. query above, is the count of distinct value that fit the bucket (10-30]

What did you see instead? Under which circumstances?

"No datapoints found."

Each query (i.e. dns_latency_bucket{le="30.0"} , dns_latency_bucket{le="10.0"}) gives me a time series values

[hoffie]

You probably need to ignore the le label. Otherwise, Prometheus tries to match it:
https://prometheus.io/docs/prometheus/latest/querying/operators/#one-to-one-vector-matches

dns_latency_bucket{le="30.0"} - ignoring(le) dns_latency_bucket{le="10.0"}

This currently sounds like a usage question. It is suggested, to ask these on the mailing list or on IRC: https://prometheus.io/community/

[elerer]

works, Thanks!

[codesome]

As @hoffie said, this is a usage question. Please use user mailing list or IRC channel mentioned here https://prometheus.io/community/ for further queries.