Re: libpq maligning postgres stability

On Thu, Mar 27, 2025 at 11:19 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
> We have several places in libpq where libpq says that a connection closing is
> probably due to a server crash with a message like:
>
> server closed the connection unexpectedly
> This probably means the server terminated abnormally
> before or while processing
>
> I think this is rather unhelpful, at least these days. There are a lot of
> reasons the connection could have failed, the server having terminated
> abnormally is just one of them.
>
> It's common to see this due to network issues, for example. I've quite a few
> times fielded worried questions of postgres users due to the message.

Yeah, I agree. I used to think this hint was helpful, but it's gotten
less helpful as the years have passed, because the server is more
stable these days. Another thing that can cause this (as discussed in
Discord) is that the individual backend process can have died, but not
the server as a whole. In that case, the hint is only accurate if you
mean "server" to read your individual server process.

I wonder if, in addition to removing the hint, we could also consider
rewording the message. For example, a slight rewording to "server
connection closed unexpectedly" would avoid implying that it was the
server that took action, which is correct, because it could be a
firewall in between the machines or even security software on the
client side. Maybe there is some more dramatic rewording that is even
better, but there's probably some value in keeping it similar to what
people are used to seeing.

--
Robert Haas
EDB: http://www.enterprisedb.com