Re: A special tool for PostgreSQL which checks its operability

On Mon, Apr 22, 2019 at 11:47 PM <AYahorau(at)ibagroup(dot)eu> wrote:

> As far as I know there is a number of tools which collect some statistics
> concerning some PostgreSQL issues
> (connections, disconnections, queries, the most frequent events etc.).
> Some of them rely on Postgres Log or use other approaches.
>
> I have a question.
> Do you know is there such a tool or a set of some actions which can give a
> precise correct information whether db server is operable or not?
> As I understand unfortunately not all the high-severity(FATAL or PANIC)
> messages in Postgres Log are really serious.

It depends on what "operable" means in your context. To answer the basic
"is Postgres up and accepting connections?" question, have a look at
pg_isready:
https://www.postgresql.org/docs/current/app-pg-isready.html

The only FATAL I can think of offhand that _may_ be ignorable (depending on
your situation), is the FATAL thrown by too many connections. My opinion is
that every FATAL, and certainly every PANIC, is grounds for immediate
investigation.