Re: Feature request: make cluster_name GUC useful for psql prompts

Steve Crawford <scrawford(at)pinpointresearch(dot)com> writes:

> That is almost identical to the solution I suggested a week or two ago to someone tackling the issue and the hack works on initial connection.
>
> Connect to a different cluster with "\c", however, and it will leave the prompt showing you connected to the original database which is not good.

True and I've always thought of it as a possible misfeature of psql that
it scans .psqlrc only once.

> Cheers,
> Steve
>
> On Fri, May 6, 2016 at 11:42 AM, Jerry Sievers <gsievers19(at)comcast(dot)net> wrote:
>
> Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
>
> > On 5/5/16 9:21 PM, Steve Crawford wrote:
> >
> >> Adding an escape sequence that references cluster_name would enable
> >> prompts to identify the cluster in a manner that is both consistent and
> >> distinct regardless of access path.
> >
> > I think that would be a good idea.  You could probably design it so
> > that any server parameter reported to the client can be put in a psql
> > prompt.
>
> The OP can easily work around that lack of support with something such as follow...
>
> Add this to ~/.psqlrc[-optional version stuff]
>
> select setting as cluster_name from pg_settings where name = 'cluster_name'  -- do not simicolon terminate this line
> \gset
>
> \set PROMPT1 :cluster_name ': how cool is this:'
>
> >
> >> Potential issues/improvements:
> >>
> >> What should the escape-sequence display if cluster_name is not set or
> >> the cluster is a pre-9.5 version. %M? %m?
> >>
> >> In future server versions should there be a default for cluster_name if
> >> it is not set? If so, what should it be? Would the server canonical
> >> hostname + listen-port be reasonable?
> >
> > Those are good questions.  I don't really like the proposed answers,
> > because that could cause confusion in practical use.
> >
> > --
> > Peter Eisentraut              http://www.2ndQuadrant.com/
> > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>
> --
> Jerry Sievers
> Postgres DBA/Development Consulting
> e: postgres(dot)consulting(at)comcast(dot)net
> p: 312.241.7800
>

--
Jerry Sievers
e: jerry(dot)sievers(at)comcast(dot)net
p: 312.241.7800