Re: BUG #17789: process_pgfdw_appname() fails for autovacuum workers

On Wed, Feb 15, 2023 at 04:12:54PM +0900, Kyotaro Horiguchi wrote:
> By the way, when we designed that part, we first concluded that the
> user name and database name cannot be NULL before we later concluded
> that MyProcPort cannot be NULL. However, log_status_format() takes
> into account the case where MyProcPort stores NULL as user and
> database names.  Do you think we should still ignore the case of NULL
> user name and database names, even though our assumption about
> MyProcPort was found to be incorrect? In that case,
> log_status_format() replaces, for example, %u with '[unknown]'.

Hmm.  I think that I would play it safe but consistent here for %d and
%u as this code could be triggered in various contexts as far as I
understand:
- When MyProcPort is NULL, insert no data, because there is nothing to
report.
- When MyProcPort is not NULL but the %d or %u field is NULL, use
[unknown], because we just don't know what to show up, still there is
a MyProcPort.

This has the advantage to be able to make the difference in both
cases, which could be important for the end-user depending on the
context where the code is run.
--
Michael