Re: proposal: psql: show current user in prompt

I'm very much in favor of adding a way to support reporting other GUC
variables than the current hardcoded list. This can be quite useful to
support some amount of session state in connection poolers.

Some general feedback on the patch:
1. I don't think the synchronization mechanism that you added should
be part of PQlinkParameterStatus. It seems likely for people to want
to turn on reporting for multiple GUCs in one go. Having to
synchronize for each would introduce unnecessary round trips. Maybe
you also don't care about syncing at all at this point in time.

2. Support for this message should probably require a protocol
extension. There is another recent thread that discusses about adding
message types and protocol extensions:
https://www.postgresql.org/message-id/flat/CA%2BTgmoaxfJ3whOqnxTjT-%2BHDgZYbEho7dVHHsuEU2sgRw17OEQ%40mail.gmail.com#acd99fde0c037cc6cb35d565329b6e00

3. Some tests for this new libpq API should be added in
src/test/modules/libpq_pipeline

4. s/massages/messages

Finally, I think this patch should be split into two commits:
1. adding custom GUC_REPORT protocol support+libpq API
2. using this libpq API in psql for the user prompt

If you have multiple commits (which are rebased on master), you can
very easily create multiple patch files using this command:
git format-patch master --base=master --reroll-count={version_number_here}

On Fri, 28 Apr 2023 at 07:00, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> wrote:
>
>
>
> čt 27. 4. 2023 v 7:39 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> napsal:
>>
>> Hi
>>
>> rebased version + fix warning possibly uninitialized variable
>
>
> fix not unique function id
>
> Regards
>
> Pavel
>
>>
>> Regards
>>
>> Pavel
>>