From: Sean O'Grady <sean@thingee.com>
To: pgsql-admin@lists.postgresql.org <pgsql-admin@lists.postgresql.org>
To: Wetmore, Matthew (CTR) <matthew.wetmore@express-scripts.com>
Subject: Re: Question about wal_compression and what to expect
Date: Wed, 21 Jun 2023 09:51:15 -0400
Message-ID: <dc513dfe7b83c8049c8599cbde146320ca14f317@hey.com> (raw)
In-Reply-To: <f875f6df936b4a07b066b6cb04ef7abf@express-scripts.com>
Yes, my question was essentially do I need to separately compress WAL
files for storage/archiving even with wal_compression set. So, I think
you've answered my question.
Thanks!
Sean
On June 20, 2023, "Wetmore, Matthew (CTR)" <matthew.wetmore@express-
scripts.com> wrote:
> From my understanding,
>
>
>
> Wal_compression will compress full page writes in the wal file. The
> size of your wal is configurable.
>
>
>
> So for your 16MB wal, it’s already compressed into the wal, and your
> wal_size won’t change. (just more data can fit into your 16MB)
>
>
>
> As far as archiving, I create a dir, then tar.gz the dir for storage.
> (if that was your question)
>
>
>
>
>
>
>
> From: Sean O'Grady <sean@thingee.com>
> Sent: Tuesday, June 20, 2023 11:19 AM
> To: pgsql-admin@lists.postgresql.org
> Subject: [EXTERNAL] Question about wal_compression and what to expect
>
>
>
> Hello,
>
> I've enabled wal_compression however I do not see any change in the
> 16MB size for each WAL file. Through all my googling and searching the
> mailing lists, I could not find a description if a change *should* be
> expected even though many of the articles I've read indicate
> compression can save disk space.
>
> I am currently thinking that the records in the WAL file are
> compressed for the purpose of writing less data to disk, but that the
> file is still padded to 16MB. If so, does that mean to realize a space
> savings for archiving that my archive_command should compress the file
> (gzip, bz2, etc)?
>
> Thanks,
> Sean O'Grady
>
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To: pgsql-admin@postgresql.org
Cc: sean@thingee.com, pgsql-admin@lists.postgresql.org, matthew.wetmore@express-scripts.com
Subject: Re: Question about wal_compression and what to expect
In-Reply-To: <dc513dfe7b83c8049c8599cbde146320ca14f317@hey.com>
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