PostgreSQL_CommitRateTooLow Alert

I received an alert for PostgreSQL_CommitRateTooLow for postgres-01. Upon investigation, it doesn't look like postgres-01 is getting any traffic at all since the failover. I would have expected it to simply join the load-balancing pool, but it doesn't seem like that happens automatically.

this section of the gitlab-base role defines the db_load_balancing hosts. Since postgres-01 was primary, it isn't listed there.

I'm unsure the implications of updating this value, for example will it cause downtime?

Either way, we should also see if we can find a way for this to happen automatically.

cc/ @_stark @gl-infra