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In-Reply-To: <3f748033-4679-44c2-a74d-b3306528e443@vondra.me>
From: Peter Geoghegan <pg@bowt.ie>
Date: Thu, 12 Mar 2026 13:27:00 -0400
Message-ID: 
 <CAH2-Wz=Qv3wmhPnryeC_TsiETP9H=btQgssSRffzJW3XmyNNXw@mail.gmail.com>
Subject: Re: index prefetching
To: Tomas Vondra <tomas@vondra.me>
Cc: Andres Freund <andres@anarazel.de>,
 Alexandre Felipe <o.alexandre.felipe@gmail.com>,
	Thomas Munro <thomas.munro@gmail.com>,
 Nazir Bilal Yavuz <byavuz81@gmail.com>,
	Robert Haas <robertmhaas@gmail.com>,
 Melanie Plageman <melanieplageman@gmail.com>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Georgios <gkokolatos@protonmail.com>,
	Konstantin Knizhnik <knizhnik@garret.ru>, Dilip Kumar <dilipbalaut@gmail.com>
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On Thu, Mar 12, 2026 at 10:43=E2=80=AFAM Tomas Vondra <tomas@vondra.me> wro=
te:
> I took a quick look at 0001 and 0002 patches, and I think it's mostly
> ready to go.

Pushed both patches just now. Thanks for the review!

> I only have a couple very minor comments:
>
> 1) v12-0001-Use-simple-hash-for-PrivateRefCount.patch

> - the "common/hashfn.h" include seems in the wrong place

Fixed in the pushed patch.

> 2) v12-0002-Don-t-allocate-_bt_search-stack.patch
>
> - seems like a reasonable optimization for most callers
> - _bt_search could set "stack_in =3D new_stack;" in the first if block, I
> think it's nicer

Agreed. Done that way in the commit that I pushed.

> - My only concern is that _bt_search is part of the public API (at least
> technically, as it's in nbtree.h), and we're removing _bt_freestack()
> from the API so the callers won't have a convenient way to free it.
> Maybe that's not an issue in practice, because doing a local version of
> freestack is easy.

I don't think that it's an issue. _bt_search is very much an
nbtree-internal function (amcheck notwithstanding), and as you point
out it's easy enough for an extension to create its own version of
_bt_freestack in the unlikely event that it needs to.

--
Peter Geoghegan