From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
cc: Hubert Zhang <zhubert@vmware.com>, tsunakawa.takay@fujitsu.com,
        pgsql-hackers@postgresql.org,
 Andreas Seltenreich <seltenreich@gmx.de>,
        Bruce Momjian <bruce@momjian.us>
Subject: Re: Multiple hosts in connection string failed to failover in non-hot
 standby mode
In-reply-to: <20210506162651.GJ27406@telsasoft.com>
References: 
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 <TYAPR01MB299012CAC510D2644AEC2246FE160@TYAPR01MB2990.jpnprd01.prod.outlook.com>
 <BN6PR05MB3492DFB2FF32B771172CC2F2C9170@BN6PR05MB3492.namprd05.prod.outlook.com>
 <229507.1610056206@sss.pgh.pa.us> <770711.1610318330@sss.pgh.pa.us>
 <20210506162651.GJ27406@telsasoft.com>
Comments: In-reply-to Justin Pryzby <pryzby@telsasoft.com>
	message dated "Thu, 06 May 2021 11:26:51 -0500"
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Date: Thu, 06 May 2021 13:22:27 -0400
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Justin Pryzby <pryzby@telsasoft.com> writes:
> 52a10224 broke sqlsmith, of all things.

> It was using errmsg as a test of success, instead of checking if the con=
nection
> result wasn't null:

>      conn =3D PQconnectdb(conninfo.c_str());
>      char *errmsg =3D PQerrorMessage(conn);
>      if (strlen(errmsg))
>          throw dut::broken(errmsg, "08001");

> That's clearly the wrong thing to do, but maybe this should be described=
 in the
> release notes as a compatibility issue, in case other people had the sam=
e idea.
> Clearing errorMessage during success is an option..

Hm.  I'd debated whether to clear conn->errorMessage at the end of
a successful connection sequence, and decided not to on the grounds
that it might be interesting info (eg it could tell you why you
ended up connected to server Y and not server X).  But perhaps
it's too much of a compatibility break for this small benefit.

I'm curious though why it took this long for anyone to complain.
I'd supposed that people were running sqlsmith against HEAD on
a pretty regular basis.

			regards, tom lane