This is recommended by the Prometheus docs - https://prometheus.io/docs/practices/naming/
A metric name...
...must comply with the data model for valid characters.
...should have a (single-word) application prefix relevant to the domain the metric belongs to. The prefix is sometimes referred to as namespace by client libraries. For metrics specific to an application, the prefix is usually the application name itself. Sometimes, however, metrics are more generic, like standardized metrics exported by client libraries. Examples:
prometheus_notifications_total (specific to the Prometheus server)
process_cpu_seconds_total (exported by many client libraries)
http_request_duration_seconds (for all HTTP requests)
It is also awkward in tools like grafana to find impala metrics with the current naming scheme.