From: David Fetter <david@fetter.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Stephen Frost <sfrost@snowman.net>
Cc: Andres Freund <andres@anarazel.de>
Cc: PostgreSQL Development <pgsql-hackers@postgresql.org>
Subject: Re: New EXPLAIN option: ALL
Date: Wed, 15 May 2019 16:20:34 +0200
Message-ID: <20190515142033.GB28936@fetter.org> (raw)
In-Reply-To: <30903.1557927151@sss.pgh.pa.us>
References: <20190507163411.GM28936@fetter.org>
<20190507164430.a7tig676hjzdnyyd@alap3.anarazel.de>
<20190507212355.GQ28936@fetter.org>
<20190507215449.3a4yb5kkoloq7yyw@alap3.anarazel.de>
<4638.1557266803@sss.pgh.pa.us>
<20190507221255.GO6197@tamriel.snowman.net>
<5221.1557267912@sss.pgh.pa.us>
<20190513055112.GA24409@fetter.org>
<20190515060214.GZ28936@fetter.org>
<30903.1557927151@sss.pgh.pa.us>
On Wed, May 15, 2019 at 09:32:31AM -0400, Tom Lane wrote:
> David Fetter <david@fetter.org> writes:
> > I hope the patch is a little easier to digest as now attached.
>
> To be blunt, I find 500K worth of changes in the regression test
> outputs to be absolutely unacceptable, especially when said changes
> are basically worthless from a diagnostic standpoint.
You're right, of course. The fundamental problem is that our
regression tests depend on (small sets of) fixed strings. TAP is an
alternative, and could test the structure of the output rather than
what really should be completely inconsequential changes in its form.
> There are
> at least two reasons why this won't fly:
>
> * Such a change would be a serious obstacle to back-patching
> regression test cases that involve explain output.
>
> * Some buildfarm members use nonstandard settings (notably
> force_parallel_mode, but I don't think that's the only one).
> We are *not* going to maintain variant output files to try to cope
> with all those combinations. It'd be even more disastrous for
> private forks that might have their own affected settings.
Indeed. I think we should move our regression tests to TAP and
dispense with this.
> I don't know how to make progress towards the original goal without
> having a regression-test disaster, but what we have here is one.
This just highlights a disaster already in progress. I'm volunteering
to help fix it.
Best,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778
Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-hackers@postgresql.org
Cc: david@fetter.org, tgl@sss.pgh.pa.us, sfrost@snowman.net, andres@anarazel.de
Subject: Re: New EXPLAIN option: ALL
In-Reply-To: <20190515142033.GB28936@fetter.org>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox