Subject: Re: Getting rid of "unknown error" in dblink and
 postgres_fdw
To: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgreSQL.org
References: <19872.1482338965@sss.pgh.pa.us>
From: Joe Conway <mail@joeconway.com>
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Message-ID: <dfa45c48-659c-caa8-76de-06006707c3aa@joeconway.com>
Date: Wed, 21 Dec 2016 09:22:25 -0800
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From: Joe Conway <mail@joeconway.com>
To: Tom Lane <tgl@sss.pgh.pa.us>, pgsql-hackers@postgreSQL.org
Message-ID: <dfa45c48-659c-caa8-76de-06006707c3aa@joeconway.com>
Subject: Re: [HACKERS] Getting rid of "unknown error" in dblink and
 postgres_fdw
References: <19872.1482338965@sss.pgh.pa.us>
In-Reply-To: <19872.1482338965@sss.pgh.pa.us>
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On 12/21/2016 08:49 AM, Tom Lane wrote:
> We have a report in pgsql-general of a dblink query failing with
> 	ERROR: unknown error
> This is, to say the least, unhelpful.  And it violates our error
> message style guidelines.
>=20
> Where that is coming from is a situation where we've failed to extract
> any primary message from a remote error.  (I theorize that today's report
> is triggered by an out-of-memory situation, but that's only an unsupported
> guess at the moment.)
>=20
> I propose that we should change that string to "could not obtain message
> string for error on connection "foo"", or something along that line.
>=20
> postgres_fdw has the same disease.  It wouldn't have the notion of a named
> connection, but maybe we could insert the foreign server name instead.
>=20
> A possible objection is that if we really are on the hairy edge of OOM,
> trying to construct such error strings might push us over the edge and
> then you get "out of memory" instead.  But IMO that's not worse; it
> could be argued to be a more useful description of the problem.
>=20
> Comments?

Seems reasonable to me. I can work on it if you'd like. Do you think
this should be backpatched?

Joe


--=20
Crunchy Data - http://crunchydata.com
PostgreSQL Support for Secure Enterprises
Consulting, Training, & Open Source Development


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