Feedback-ID: i0fe9450f:Fastmail
Date: Thu, 9 May 2024 08:57:32 +0900
From: Michael Paquier <michael@paquier.xyz>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>,
	Matthias van de Meent <boekewurm+postgres@gmail.com>,
	Tomas Vondra <tomas.vondra@enterprisedb.com>,
	Josef =?utf-8?B?xaBpbcOhbmVr?= <josef.simanek@gmail.com>,
	pgsql-hackers@lists.postgresql.org
Subject: Re: bug: copy progress reporting of backends which run multiple COPYs
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On Wed, May 08, 2024 at 10:07:15AM -0400, Robert Haas wrote:
> I think you're hoping for too much. The progress reporting
> infrastructure is fundamentally designed around the idea that there
> can only be one progress-reporting operation in progress at a time.
> For COPY, that is, I believe, true, but for file_fdw, it's false. If
> we want to do any kind of progress reporting from within plannable
> queries, we need some totally different and much more complex
> infrastructure that can report progress for, probably, each plan node
> individually. I think it's likely a mistake to try to shoehorn cases
> like this into the infrastructure
> that we have today. It will just encourage people to try to use the
> current infrastructure in ways that are less and less like what it was
> actually designed to do; whereas what we should be doing if we want
> this kind of functionality, at least IMHO, is building infrastructure
> that's actually fit for purpose.

Hmm.  OK.  I have been looking around for cases out there where
BeginCopyFrom() could be called with a pstate where the reporting
could matter, and could not find anything worth worrying about.  It
still makes me a bit uneasy to not have a separate argument in the
function to control that.  Now, if you, Justin and Matthias agree with
this approach, I won't stand in the way either.
--
Michael

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