Date: Sun, 9 Aug 2026 19:25:26 +0200
From: Christoph Berg <myon@debian.org>
To: Tomas Vondra <tomas@vondra.me>
Cc: Michael Paquier <michael@paquier.xyz>,
	Andrey Borodin <x4mmm@yandex-team.ru>, Ken Marshall <ktm@rice.edu>,
	Hannu Krosing <hannuk@google.com>,
	Andreas Karlsson <andreas@proxel.se>,
	wenhui qiu <qiuwenhuifx@gmail.com>,
	Laurenz Albe <laurenz.albe@cybertec.at>,
	Andres Freund <andres@anarazel.de>,
	Jelte Fennema-Nio <postgres@jeltef.nl>,
	Japin Li <japinli@hotmail.com>, Fujii Masao <masao.fujii@gmail.com>,
	pgsql-hackers <pgsql-hackers@postgresql.org>,
	John Naylor <johncnaylorls@gmail.com>
Subject: Re: WAL compression setting after PostgreSQL LZ4 default change
Message-ID: <ani4BpccmFfbO9dq@msg.df7cb.de>
Mail-Followup-To: Christoph Berg <myon@debian.org>,
	Tomas Vondra <tomas@vondra.me>,
	Michael Paquier <michael@paquier.xyz>,
	Andrey Borodin <x4mmm@yandex-team.ru>, Ken Marshall <ktm@rice.edu>,
	Hannu Krosing <hannuk@google.com>,
	Andreas Karlsson <andreas@proxel.se>,
	wenhui qiu <qiuwenhuifx@gmail.com>,
	Laurenz Albe <laurenz.albe@cybertec.at>,
	Andres Freund <andres@anarazel.de>,
	Jelte Fennema-Nio <postgres@jeltef.nl>,
	Japin Li <japinli@hotmail.com>, Fujii Masao <masao.fujii@gmail.com>,
	pgsql-hackers <pgsql-hackers@postgresql.org>,
	John Naylor <johncnaylorls@gmail.com>
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Re: Tomas Vondra
> +        The supported methods are <literal>off</literal>, <literal>on</literal>,
> +        <literal>lz4</literal> (if <productname>PostgreSQL</productname> was compiled with <option>--with-lz4</option>),
> +        <literal>zstd</literal> (if <productname>PostgreSQL</productname> was compiled with <option>--with-zstd</option>), and
> +        <literal>pglz</literal>.
> +        The value <literal>on</literal> selects the first of <literal>zstd</literal>,
> +        <literal>lz4</literal>, <literal>pglz</literal> that is available.

>  #wal_compression = off                  # enables compression of full-page writes;
> -                                        # off, pglz (or "on"), lz4, or zstd
> +                                        # off, on, lz4, zstd, or pglz (on means the first
> +                                        # of zstd, lz4 and pglz, supported by the build)

I would put zstd before lz4 in both places as it's preferred over it.

Christoph