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

Peter Eisentraut <peter.eisentraut@2ndquadrant.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.consulting@comcast.net
p: 312.241.7800