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From: Greg Sabino Mullane <htamfids@gmail.com>
Date: Wed, 17 Dec 2025 12:21:03 -0500
Message-ID: <CAKAnmm+yoNEQCV3qXceXm9rNoOAPYK0DQCpSqLkNGvGuOQ3W=A@mail.gmail.com>
Subject: Re: wal segment size
To: "Colin 't Hart" <colinthart@gmail.com>
Cc: Laurenz Albe <laurenz.albe@cybertec.at>, 
	PostgreSQL General <pgsql-general@lists.postgresql.org>
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On Wed, Dec 17, 2025 at 11:10=E2=80=AFAM Colin 't Hart <colinthart@gmail.co=
m> wrote:

> Thanks Laurenz, that confirms what I was assuming. Archiving is via
> pgbackrest to a backup server, over SSH. Approx 750ms to archive each
> segment is crazy -- I'll check compression parameters too.
>

Switch to archive-async =3D on. When doing that, the typical time drops to
10ms or less. Also use a compress-type of lz4 or zst, which perform way
better than the default gz. If you are encrypting, that's a bottleneck you
just have to deal with, no shortcuts there. :)

tl;dr try other things before messing with the WAL size. The current size
can work very well even on very large and very, very busy systems.

Cheers,
Greg

--
Crunchy Data - https://www.crunchydata.com
Enterprise Postgres Software Products & Tech Support

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<div dir=3D"ltr"><div dir=3D"ltr">On Wed, Dec 17, 2025 at 11:10=E2=80=AFAM =
Colin &#39;t Hart &lt;<a href=3D"mailto:colinthart@gmail.com">colinthart@gm=
ail.com</a>&gt; wrote:</div><div class=3D"gmail_quote gmail_quote_container=
"><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;borde=
r-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"ltr"><div>T=
hanks Laurenz, that confirms what I was assuming. Archiving is via pgbackre=
st to a backup server, over SSH. Approx 750ms to archive each segment is cr=
azy -- I&#39;ll check compression parameters too.</div><div></div></div></b=
lockquote><div><br></div><div>Switch to archive-async =3D on. When doing th=
at, the typical time drops to 10ms or less. Also use a compress-type of lz4=
 or zst, which perform way better than the default gz. If you are encryptin=
g, that&#39;s a bottleneck you just have to deal with, no shortcuts there. =
:)</div><div><br></div><div>tl;dr try other things before messing with the =
WAL size. The current size can work very well even on very large and very, =
very busy systems.</div><div><br></div><div>Cheers,</div></div><div dir=3D"=
ltr" class=3D"gmail_signature"><div dir=3D"ltr"><div>Greg</div><div><br></d=
iv><div>--</div><div>Crunchy Data - <a href=3D"https://www.crunchydata.com"=
 target=3D"_blank">https://www.crunchydata.com</a></div><div>Enterprise Pos=
tgres Software Products &amp; Tech Support</div><div><br></div></div></div>=
</div>

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