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Re: wal segment size

Laurenz Albe <laurenz.albe@cybertec.at>

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From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Colin 't Hart <colinthart@gmail.com>, PostgreSQL General <pgsql-general@lists.postgresql.org>
Date: 2025-12-17T15:25:17Z
Lists: pgsql-general 
On Wed, 2025-12-17 at 16:13 +0100, Colin 't Hart wrote:
> I see very little advice on tuning WAL segment size.
> 
> One of my clients has a few datawarehouses at around 8 - 16 TB
> 
> On one of the nodes there are approx 15000 WAL segments of 16MB each, totalling
> approx 230GB. The archiver is archiving approx one per second, so approx 4 hours to clear.
> 
> Would we gain anything by bumping the WAL segment size?

Very likely yes, if the problem is the overhead of starting the archive_command.

Another thing that can slow down archiving is if you compress these segments
too aggressively.

Yours,
Laurenz Albe