From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
cc: ANASTACIO Tiago <tiago_anastacio@yahoo.fr>, Peter Geoghegan <pg@bowt.ie>,
        PostgreSQL mailing lists <pgsql-bugs@lists.postgresql.org>
Subject: Re: BUG #15726: parallel queries failed ERROR: invalid name syntax
 CONTEXT: parallel worker
In-reply-to: 
 <CA+hUKGLvwuKEf_dk-zZANRLGfT9eO5hbKB_+KYeb-Uef_Q7G-g@mail.gmail.com>
References: <15726-6d67e4fa14f027b3@postgresql.org>
 <CA+hUKG+BcXXqqRb1JNbUXYKyNXzyyOqvebYN+9DGqGY6UPtLQQ@mail.gmail.com>
 <CA+hUKGKJ-amPMuwFhgc5T6UH=Wcn3CG3gmowmkYqTo2WsQJM4A@mail.gmail.com>
 <CA+hUKGLdzBsa_SZajU8J9JDSHzdU6+LVq1g6bUsekiWBpjVDNQ@mail.gmail.com>
 <CAH2-Wzkif1R6imAhgcRv1cXqomYBDez9g1rKAhDixiEi7b2KOg@mail.gmail.com>
 <1831482307.24522245.1554199154256@mail.yahoo.com>
 <CA+hUKGLvwuKEf_dk-zZANRLGfT9eO5hbKB_+KYeb-Uef_Q7G-g@mail.gmail.com>
Comments: In-reply-to Thomas Munro <thomas.munro@gmail.com>
	message dated "Tue, 02 Apr 2019 23:23:11 +1300"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <29887.1554218381.1@sss.pgh.pa.us>
Date: Tue, 02 Apr 2019 11:19:41 -0400
Message-ID: <29888.1554218381@sss.pgh.pa.us>
Precedence: bulk

Thomas Munro <thomas.munro@gmail.com> writes:
> On Tue, Apr 2, 2019 at 10:59 PM ANASTACIO Tiago
> <tiago_anastacio@yahoo.fr> wrote:
>> A pity background worker are no more verbose (DEBUG5) than:
>> 2019-04-02 09:42:38.993 GMT [17654] ERROR:  invalid name syntax

> I agree, it would be nice to improve that.  It seems to be a general
> problem with any GUC that requires a transaction to check: parallel
> workers will force that, but you might not understand the error
> because it comes with no context.  That gives me an idea: perhaps we
> should set the elog() context while restoring GUCs, so that it is
> displayed in the error output somehow.

Yeah, something like

CONTEXT: while setting parameter guc_variable_name to "some value"

would likely make this a whole lot more comprehensible.  And I think
it could probably be done in a fairly centralized way using an error
callback.

			regards, tom lane