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From: Robert Haas <robertmhaas@gmail.com>
Date: Sun, 26 Apr 2026 13:12:06 -0400
Message-ID: 
 <CA+TgmoZRs3ArQC_rkVCx_Q7rWCM+QF-Q6ERRYUaN4tUvr+rd7w@mail.gmail.com>
Subject: Re: Use log_newpage_range in HASH index build
To: lakshmi <lakshmigcdac@gmail.com>
Cc: Kirill Reshke <reshkekirill@gmail.com>,
 pgsql-hackers <pgsql-hackers@postgresql.org>
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On Mon, Jan 5, 2026 at 3:48=E2=80=AFAM lakshmi <lakshmigcdac@gmail.com> wro=
te:
> Following up on my earlier note, I implemented the proposed HASH overflow=
 page reuse enhancement.Recently freed overflow pages are recorded in
> _hash_freeovflpage( ),and _hash_addovflpage( ) now prefers reusing those =
pages during allocation before falling back to the bitmap scan.
>
> The change is backend-local and allocation-only,with no WAL or on-disk fo=
rmat changes.I verified correctness using index build/drop and VACUUM cycle=
s,and confirmed WAL neutrality by comparing WAL generated during HASH index=
 builds with and without this change (no  observable difference beyond norm=
al noise).
>
> The patch is attached for review.Feedback is welcome.

It is probably best to start a separate email thread specifically
about this patch, because it's doing something quite different from
the original patch. I suggest presenting some specific performance
results, as it's not very clear how much benefit this might have. It
might be good to test a favorable scenario and also an unfavorable
scenario, describing and showing results for each.

--=20
Robert Haas
EDB: http://www.enterprisedb.com