Re: psql \watch always ignores \pset null

On Tue, Nov 18, 2014 at 9:54 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>
> Fujii Masao <masao(dot)fujii(at)gmail(dot)com> writes:
> > Hi,
> >> /*
> >> * Set up rendering options, in particular, disable the pager, because
> >> * nobody wants to be prompted while watching the output of 'watch'.
> >> */
> >> myopt.nullPrint = NULL;
> >> myopt.topt.pager = 0;
>
> > I found psql's \watch command always ignores \pset null setting.
> > The above source code comment explains why it does,
> > but I'd like to see the specified string for null value even in \watch's
> > output, in order to distinguish null and an empty value. Thought?
> > Is there any reason why \watch must ignore \pset null setting?
>
> Hmmm ... the comment offers a reasonable argument for forcing pager = 0,
> but I agree the nullPrint change is not adequately explained.
> Will, do you remember why you did that?
>
> regards, tom lane

I tracked down the individual commit[1] from my history where I added
that. What I added there is very similar to sections in
src/bin/psql/describe.c. I can't remember specifically my reasoning
then, but it's likely I copied the patterns there while getting things
working.

I do still think it's important to remove the pager, but the nullPrint
is probably a mistake.

[1]: https://github.com/will/postgres/commit/c42d29fece16ec9cb13c159b3307ab9fca892eb2