Re: bug: copy progress reporting of backends which run multiple COPYs

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