Re: proposal: psql: show current user in prompt

po 4. 9. 2023 v 14:24 odesílatel Jelte Fennema <postgres(at)jeltef(dot)nl> napsal:

> On Sun, 3 Sept 2023 at 20:58, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
> wrote:
> > here is an try
>
> Overall it does what I had in mind. Below a few suggestions:
>
> +int
> +PQprotocolSubversion(const PGconn *conn)
>
> Ugh, it's quite annoying that the original PQprotocolVersion only
> returns the major version and thus we need this new function. It
> seems like it would be much nicer if it returned a number similar to
> PQserverVersion. I think it might be nicer to change PQprotocolVersion
> to do that than to add another function. We could do:
>
> return PG_PROTOCOL_MAJOR(conn->pversion) * 100 +
> PG_PROTOCOL_MINOR(conn->pversion);
>
> or even:
>
> if (PG_PROTOCOL_MAJOR(conn->pversion) == 3 &&
> PG_PROTOCOL_MINOR(conn->pversion))
> return 3;
> else
> return PG_PROTOCOL_MAJOR(conn->pversion) * 100 +
> PG_PROTOCOL_MINOR(conn->pversion);
>
> The second option would be safest backwards compatibility wise, but in
> practice you would only get another value than 3 (or 0) when
> connecting to pre 7.4 servers. That seems old enough that I don't
> think anyone is actually calling this function. **I'd like some
> feedback from others on this though.**
>

Both versions look a little bit strange to me. I have not strong opinion
about it, but I am not sure if is best to change contract after 20 years ago

commit from Jun 2003 efc3a25bb02ada63158fe7006673518b005261ba

I prefer to introduce a new function - it is ten lines of code. The form is
not important - it can be a full number or minor number. It doesn't matter
I think. But my opinion in this area is not strong, and I like to see
feedback from others too. It is true that this feature and interface is not
fully complete.

Reards

Pavel

> + /* The protocol 3.0 is required */
> + if (PG_PROTOCOL_MAJOR(their_version) == 3)
> + conn->pversion = their_version;
>
> Let's compare against the actual PG_PROTOCOL_EARLIEST and
> PG_PROTOCOL_LATEST to determine if the version is supported or not.
>