Support for histograms

[netikras]

Is your feature request related to a problem? Please describe.
I cannot find any examples showing how to set up HISTOGRAM metrics. Are there any? If histograms aren't supported - could their support be added?

While on the topic, could the examples be reviewed and provided for all types of metrics?
I'm coming from this: prometheus-community/postgres_exporter#801 (comment)

Describe the solution you'd like

• examples showing how to select data and represent as all the supported types: labels, counters, gauges, histograms, etc. (I'm assuming this is the set that should/could be supported?)
• Implement support for all the metric types used by Prometheus/Grafana.
• Document both the points above in the README.md

Describe alternatives you've considered
I've been using posgres-exporter, but it's dropping its support for arbitrary queries and they are promoting sql_exporter as a viable alternative

[burningalchemist]

Hi @netikras, thank you for your interest and suggestions!

For the time being the only supported Prometheus types from available ones are Counters and Gauges (i.e. we miss Histograms and Summaries). You can find existing examples for these, and also using labels in the repository. Feel free to create a discussion topic in case you need some additional help. 👍

Histograms are still on the radar, however there were some issues in the past so the implementation was postponed. There also wasn't much demand for the last 5 years. Still, I'm interested in looking into them and also native histograms (the recent feature of Prometheus 2.40+). I'd need to find some free time so I hardly can give any ETA at the moment.

Since sql_exporter is focused on being lightweight and database-agnostic, our primary goal is to support more databases with generic usage patterns. So feature wise I cannot guarantee compatibility with PostgreSQL Exporter.

Let's keep this issue open, so I provide some updates here whenever I have some.