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Subject: Re: eliminate xl_heap_visible to reduce WAL (and eventually set VM
 on-access)
From: Chao Li <li.evan.chao@gmail.com>
In-Reply-To: <0AC177F5-5E26-45EE-B273-357C51212AC5@gmail.com>
Date: Mon, 24 Nov 2025 16:07:59 +0800
Cc: Kirill Reshke <reshkekirill@gmail.com>,
 Andres Freund <andres@anarazel.de>,
 Robert Haas <robertmhaas@gmail.com>,
 Andrey Borodin <x4mmm@yandex-team.ru>,
 PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Heikki Linnakangas <hlinnaka@iki.fi>
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To: Melanie Plageman <melanieplageman@gmail.com>
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> On Nov 21, 2025, at 09:09, Chao Li <li.evan.chao@gmail.com> wrote:
>=20
> I=E2=80=99d stop here today, and continue reviewing rest commits in =
next week.

I continue reviewing today.

0004 This a pure refactoring. It splits heap_page_prune_and_freeze to =
multiple small functions. LGTM, no comment.

0005 overall good, a few nit comments as below.

0006, 0007 look good, no comment.

5 - 0005 - heapam.h
```
+	/*
+	 *
+	 * vmbuffer is the buffer that must already contain contain the =
required
+	 * block of the visibility map if we are to update it. =
blk_known_av is the
```

Nit:=20

* an unnecessary empty comment line.
* =E2=80=9Ccontain contain=E2=80=9D =3D> =E2=80=9Ccontain"=20

6 - 0005 heapam_xlog.c
```
+		 * The critical integrity requirement here is that we =
must never end
+		 * up with with the visibility map bit set and the =
page-level
```

Nit: =E2=80=9Cwith with=E2=80=9D =3D> =E2=80=9Cwith=E2=80=9D

I will continue reviewing 0008 and rest tomorrow.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/