| From: | Peter Geoghegan <pg(at)bowt(dot)ie> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, Jesper Pedersen <jesper(dot)pedersen(at)redhat(dot)com>, Dmitry Dolgov <9erthalion6(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: MDAM techniques and Index Skip Scan patch |
| Date: | 2022-03-29 02:03:17 |
| Message-ID: | CAH2-WzkYTeY7PfaJm=dEj1yzoj7T7Racm7smX7EG_b0R1aPvDA@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Mar 28, 2022 at 5:21 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> In any case, what I was on about is _bt_preprocess_keys() and
> adjacent code. I'm surprised that those aren't more expensive
> than one palloc in _bt_first. Maybe that logic falls through very
> quickly in simple cases, though.
I assume that it doesn't really appear in very simple cases (also
common cases). But delaying the scan setup work until execution time
does seem ugly. That's probably a good enough reason to refactor.
--
Peter Geoghegan
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