Re: psql's FETCH_COUNT (cursor) is not being respected for CTEs

On Wed, Jan 4, 2023 at 6:38 PM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Wed, Jan 4, 2023 at 11:36 AM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> > As you well know, psql's FETCH_COUNT mechanism is far older than
> > single-row mode. I don't think anyone's tried to transpose it
> > onto that. I agree that it seems like a good idea to try.
> > There will be more per-row overhead, but the increase in flexibility
> > is likely to justify that.
>
> Yeah, I was vaguely worried that there might be more per-row overhead,
> not that I know a lot about this topic. I wonder if there's a way to
> mitigate that. I'm a bit suspicious that what we want here is really
> more of an incremental mode than a single-row mode i.e. yeah, you want
> to fetch rows without materializing the whole result, but maybe not in
> batches of exactly size one.

Given the low importance and very low priority of this, how about
adding it as a TODO wiki item then and maybe adding just some warning
instead? I've intentionally avoided parsing grammar and regexp so it's
not perfect (not that I do care about this too much either, as web
crawlers already have indexed this $thread). BTW I've found two
threads if know what are you looking for [1][2]

-Jakub Wartak.

[1] - https://www.postgresql.org/message-id/flat/a0a854b6-563c-4a11-bf1c-d6c6f924004d%40manitou-mail.org
[2] - https://www.postgresql.org/message-id/flat/1274761885.4261.233.camel%40minidragon