Re: add the source of param misconfigurations to error messages

Jordan Deitch <jd(at)rsa(dot)pub> writes:
> $ postgres --config-file="/etc/postgresql/10/main/postgresql.conf"
> can fail with the following error:
> postgres: superuser_reserved_connections must be less than max_connections

> This is due to the addition of the postgresql.auto.conf params.
> Would the community welcome a patch whereby this detail in contained in the error?

Seems to me it'd result in an impossibly unwieldy message, especially
once you realize you might have to deal with other value sources than
files. Adhering to the translatability guidelines (ie, "don't construct
messages out of parts") would be problematic for that too.

We already have fairly substantial support for diagnosing such mistakes
through the pg_file_settings view, though admittedly if you don't use
that *before* restarting the server, it does not help with this.

regards, tom lane