Right now all TopK metrics render their prometheus output with a "name" label containing the frequent item:

dns_top_qname3{instance="gw",name=".fe.apple-dns.net"} 2
dns_top_qname3{instance="gw",name="clientservices.googleapis.com"} 2
dns_top_qname3{instance="gw",name="gs.apple.com"} 2
dns_top_qname3{instance="gw",name="cdn2.ghostery.com"} 2
dns_top_qtype{instance="gw",name="A"} 30
dns_top_qtype{instance="gw",name="HTTPS"} 8
dns_top_qtype{instance="gw",name="AAAA"} 2

This makes "name" very high cardinality, and also hampers data exploration and graphing in e.g. Grafana, which is unable the create an automatic filter on "name" because it is ambiguous which name should be filtered.

We should change this label to be specific per TopK metric, for example "qtype3" and "qtype" in the example above. This will shard the cardinality out, and give us a way to take advantage of Grafana "Filter by Value"

HOWEVER this is a breaking change and will break existing dashboards that already use "name" so we need to handle that appropriately.