Re: proposal: psql: show current user in prompt

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kirk Wolak <wolakk(at)gmail(dot)com>, Corey Huinker <corey(dot)huinker(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: proposal: psql: show current user in prompt
Date: 2023-04-11 09:37:28
Message-ID: CAFj8pRDeOTBd4tdW=Q4LXkpU5H3Z=X3kpf=iqsMAYEHVdyY7qg@mail.gmail.com
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st 5. 4. 2023 v 18:40 odesílatel Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
napsal:

>
>
> st 5. 4. 2023 v 17:47 odesílatel Robert Haas <robertmhaas(at)gmail(dot)com>
> napsal:
>
>> On Wed, Apr 5, 2023 at 11:34 AM Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
>> wrote:
>> > If the GUC_REPORT should not be used, then only one possibility is
>> enhancing the protocol, about the possibility to read some predefined
>> server's features from the client.
>> > It can be much cheaper than SQL query, and it can be used when the
>> current transaction is aborted. I can imagine a possibility to read server
>> time or a server session role from a prompt processing routine.
>> >
>> > But for this specific case, you need to cache the role name somewhere.
>> You can simply get oid everytime, but for role name you need to access to
>> system catalogue, and it is not possible in aborted transactions. So at the
>> end, you probably should read "role" GUC.
>> >
>> > Can this design be acceptable?
>>
>> I don't think we want to add a dedicated protocol message that says
>> "send me the role GUC right now". I mean, we could, but being able to
>> tell the GUC mechanism "please send me the role GUC after every
>> command" sounds a lot easier to use.
>>
>
> I'll try it
>

here is patch with setting GUC_REPORT on role only when it is required by
prompt

Regards

Pavel

>
> Regards
>
> Pavel
>
>
>>
>> --
>> Robert Haas
>> EDB: http://www.enterprisedb.com
>>
>

Attachment Content-Type Size
psql-prompt-placeholder-N-dynamic-GUC_REPORT.patch text/x-patch 16.2 KB

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