Proposal

Use case. Why is this important?

I am upgrading to Kubernetes 1.25 / 1.26. In it, PodSecurityPolicies are deprecated. This forces me to upgrade the my Postgres Exporter Helm Chart to version 5.0.0.

Version 4.X of the helm chart allows me to specify custom queries. However, this docker image seems to be deprecating custom metrics.

My custom metrics for example, are application specific. They are not Postgres specific. Ideally I do not want to convert my queries to Go-Lang code and recompile the Postgres Exporter just for my application. Because these queries are application specific, I would never write a custom collector nor submit a pull request here.

In addition, it seems that the recommendation is to now use this tool:
https://github.com/burningalchemist/sql_exporter

However, now that means I must maintain and update Postgres Exporter, as well as SQL Exporter. This is twice the amount of work required for regular maintenance and patching. This particularly becomes burdensome when Helm Charts, Docker Images, Application Versions, and Kubernetes all need to be in-sync. This becomes very complicated at enterprise grade sizes when hundreds of Postgres servers and applications are maintained.

Is there a reason why this feature is being removed? The alternatives being provided increase the technical burden.

Note
For other visitors from Google, postgres_exporter.yml does not allow you to input custom queries. Custom queries are totally deprecated, and the Postgres Exporter Helm Chart no longer supports custom queries.

Issue Link: prometheus-community/helm-charts#3792