From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: strange error reporting
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Comments: In-reply-to Robert Haas <robertmhaas@gmail.com>
	message dated "Wed, 20 Jan 2021 12:34:30 -0500"
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Date: Wed, 20 Jan 2021 12:47:47 -0500
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Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Jan 20, 2021 at 12:19 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> But the 'could not connect to socket' part is a consequence of my
>> recent fiddling with libpq's connection failure reporting, see
>> 52a10224e.  We could discuss exactly how that ought to be spelled,
>> but the idea is to consistently identify the host that we were trying
>> to connect to.  If you have a multi-host connection string, it's
>> conceivable that "rhaas" exists on some of those hosts and not others,
>> so I do not think the info is irrelevant.

> I'm not saying that which socket I used is totally irrelevant although
> in most cases it's going to be a lot of detail. I'm just saying that,
> at least for me, when you say you can't connect to a socket, I at
> least think about the return value of connect(2), which was clearly 0
> here.

Fair.  One possibility, which'd take a few more cycles in libpq but
likely not anything significant, is to replace "could not connect to ..."
with "while connecting to ..." once we're past the connect() per se.

> Maybe it would be better if it said:

> connection to database at socket "/tmp/.s.PGSQL.5432" failed: FATAL:
> database "rhaas" does not exist

I'd be inclined to spell it "connection to server at ... failed",
but that sort of wording is surely also possible.

			regards, tom lane