Re: add the source of param misconfigurations to error messages

Andres Freund <andres@anarazel.de> writes:
> On 2018-11-13 17:33:01 -0500, Tom Lane wrote:
>> 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.

> Note that I'm convinced this is a necessary feature.  But if we were to
> do it, I'd assume we put something like this in the DETAIL not the
> ERROR itself. That ought to alievate some of those concerns?

It would still be pretty unwieldy.

>> 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.

> Would be kind of useful if --describe-config, or a version thereof,
> would print that kind of information too.

Hmm, that's an idea.  We could probably refactor the pg_file_settings
infrastructure so it could be invoked by a command line option (maybe call
it --debug-config?) and just dump the results to stdout.  That would have
the advantage that it could report on more than one error, if there is
one.

            regards, tom lane