Re: [PATCH] Add support for displaying database service in psql prompt

On Sun, Jul 06, 2025 at 08:00:09PM -0700, Noah Misch wrote:
> I think the choice to make there is whether to call PQconninfo() once per
> prompt emission or to cache the value, invalidating that cache e.g. once per
> SyncVariables().  My first thought was to cache, but the decision is not too
> important.  A PQconninfo() call is likely negligible relative to all that
> happens between prompts.  Even if not negligible, the overhead of not caching
> will affect only prompts using the new escape sequence.

SyncVariables() happens at startup and when re-syncing a connection
during a check, so that does not really worry me.

By the way, there is a second change in the CF that's suggesting the
addition of a SERVICEFILE variable, which also uses a separate libpq
API (forgot about this one):
https://commitfest.postgresql.org/patch/5387/

Changing the patch on the other thread to use a conninfo is
stright-forward.  How about extending the get_service_name()@common.c
I've proposed upthread so as it takes a string in input and it could
be reused for more connection options than only "service" so as it
could be reused there as well?
--
Michael