Horton

Re: WAL compression setting after PostgreSQL LZ4 default change

Fujii Masao <masao.fujii@gmail.com>

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From: Fujii Masao <masao.fujii@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: wenhui qiu <qiuwenhuifx@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Japin Li <japinli@hotmail.com>, John Naylor <johncnaylorls@gmail.com>, Christoph Berg <myon@debian.org>
Date: 2026-07-03T02:58:52Z
Lists: pgsql-hackers 
On Wed, Jul 1, 2026 at 8:45 AM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Tue, Jun 30, 2026 at 06:25:09PM +0800, wenhui qiu wrote:
> > The recent PostgreSQL commit changes the default TOAST compression to lz4
> > when LZ4 support is available, based on the rationale that LZ4 is generally
> > more efficient than pglz in terms of CPU usage and compression
> > ratio.  Given that, should we also consider changing the default
> > compression method used by wal_compression = on from pglz to lz4?
>
> "on" is just a backward-compatible value, so we could let it as-is.

Yes, so +1 to leaving "on" as it is. Making its meaning depend on
the build options seems very confusing. Users who want lz4 or zstd
can simply specify those methods explicitly instead of using "on".

Regards,

-- 
Fujii Masao