pg_stat_activity missing arbitrarily

[cazter]

Half of our identical databases do not provide the pg_stat_activity metrics.

We run many databases, all of which built from the same helm package with variation in the configuration only on resources and naming. Otherwise, they're identical and initialized using the same SQL script.

Postgres Version: 11.8
Exporter Version: Latest

Running with log level debug, repeats the following (on both databases that do have and those that do not have pg_stat_activity metrics):

[podname-0 prom-psql-exporter] time="2020-09-29T19:03:39Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:39Z" level=debug msg="Querying pg_setting view on \"localhost:5432\"" source="pg_setting.go:15"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:39Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:44Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:44Z" level=debug msg="Querying pg_setting view on \"localhost:5432\"" source="pg_setting.go:15"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:44Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:49Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:49Z" level=debug msg="Querying pg_setting view on \"localhost:5432\"" source="pg_setting.go:15"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:49Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:54Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:54Z" level=debug msg="Querying pg_setting view on \"localhost:5432\"" source="pg_setting.go:15"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:54Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:59Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:59Z" level=debug msg="Querying pg_setting view on \"localhost:5432\"" source="pg_setting.go:15"
[podname-0 prom-psql-exporter] time="2020-09-29T19:03:59Z" level=debug msg="Querying Postgres Version on \"localhost:5432\"" source="postgres_exporter.go:1388"

[cazter]

This appears to have been our issue: #415

Though we fixed by adding a delay to the exporter startup--haven't tested the above PR.