Re: warn if GUC set to an invalid shared library

On Tue, Dec 28, 2021 at 12:45 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> 0002 adds context when failing to start.
>
>         2021-12-27 17:01:12.996 CST postmaster[1403] WARNING:  could not load library: $libdir/plugins/asdf: cannot open shared object file: No such file or directory
>         2021-12-27 17:01:14.938 CST postmaster[1403] FATAL:  could not access file "asdf": No such file or directory
>         2021-12-27 17:01:14.938 CST postmaster[1403] CONTEXT:  guc "shared_preload_libraries"
>         2021-12-27 17:01:14.939 CST postmaster[1403] LOG:  database system is shut down

-1 from me on using "guc" in any user-facing error message. And even
guc -> setting isn't a big improvement. If we're going to structure
the reporting this way there, we should try to use a meaningful phrase
there, probably beginning with the word "while"; see "git grep
errcontext.*while" for interesting precedents.

That said, that series of messages seems a bit suspect to me, because
the WARNING seems to be stating the same problem as the subsequent
FATAL and CONTEXT lines. Ideally we'd tighten that somehow.

-- 
Robert Haas
EDB: http://www.enterprisedb.com