Re: [PATCH][DOC] Fix for PREPARE TRANSACTION doc and postgres_fdw message.

From: Gilles Darold <gilles(at)darold(dot)net>
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: Etsuro Fujita <etsuro(dot)fujita(at)gmail(dot)com>, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: [PATCH][DOC] Fix for PREPARE TRANSACTION doc and postgres_fdw message.
Date: 2019-11-11 15:43:18
Views: Raw Message | Whole Thread | Download mbox | Resend email
Lists: pgsql-hackers

Le 09/11/2019 à 02:22, Michael Paquier a écrit :
> On Fri, Nov 08, 2019 at 10:19:01AM +0100, Gilles Darold wrote:
>> I don't think so. The support or not of 2PC is on foreign data wrapper
>> side. In postgres_fdw contrib the error for use with 2PC is not part of
>> the test but it will be thrown anyway. I guess that a test will be
>> valuable only if there is support for readonly query.
> That's what I call a case for negative testing. We don't allow 2PC to
> be used so there is a point in having a test to make sure of that.
> This way, if the code in this area is refactored or changed, we still
> make sure that 2PC is correctly prevented. My suggestion is to close
> this gap. One point here is that this requires an alternate output
> file because of max_prepared_transactions and there is no point in
> creating one with all the tests of postgres_fdw in a single file as we
> have now as it would create 8k lines of expected file bloat, so it
> would be better to split the tests first. My 2c.
> --
> Michael

Hi Michael, it looks that a separate test is not required at least for
this test. Here is a patch that enable the test in
contrib/postgres_fdw/, expected output:

-- Make sure that 2PC is correctly prevented
SELECT count(*) FROM ft1;
(1 row)

-- Must throw an error
ERROR:  cannot PREPARE a transaction that has operated on
postgres_fdw foreign tables
WARNING:  there is no transaction in progress

Gilles Darold

Attachment Content-Type Size
patch_postgres_fdw_2pc_test-v1.diff text/x-patch 1.2 KB

In response to


Browse pgsql-hackers by date

  From Date Subject
Next Message Tom Lane 2019-11-11 15:46:07 Re: psql \d for wide tables / pattern for individual columns
Previous Message Antonin Houska 2019-11-11 15:25:56 Re: Attempt to consolidate reading of XLOG page