PostgreSQL Connection Utilization Needs a Denominator

A count of sixty active PostgreSQL connections is meaningless until it is compared with the configured maximum for that server. I ended up treating hserver_postgres_connections divided by hserver_postgres_max_connections as the useful observation point rather than relying on a generic service-up indicator. Connection pressure is a capacity ratio, which is why the alert triggers when usage remains above eighty percent instead of on an arbitrary raw count.

This is a good example of capacity-ratio alerting. The purpose is to reduce ambiguity during an incident: a signal should tell me which layer to inspect next, not simply confirm that something somewhere looks unusual.

For production I use the following guardrail: Track utilization by database and investigate pool sizing, leaked sessions and traffic growth before simply raising max_connections. The same rule keeps the dashboard useful when the system grows and more targets are added.

The implementation is traceable to b65d5d4 in the hserver repository. That commit is the concrete reference for the collector, alert, dashboard, or runtime change behind this article.