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From: David Rowley <dgrowleyml@gmail.com>
Date: Wed, 7 Jul 2021 23:44:16 +1200
Message-ID: 
 <CAApHDvpGwOAvunp-E-bN_rbAs3hmxMoasm5pzkYDbf36h73s7w@mail.gmail.com>
Subject: Re: Update maintenance_work_mem/autovacuum_work_mem to reflect the
 1GB limitation with VACUUM
To: Laurenz Albe <laurenz.albe@cybertec.at>
Cc: =?UTF-8?B?TWFydMOtbiBNYXJxdcOpcw==?= <martin.marques@gmail.com>,
	PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
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On Sun, 4 Jul 2021 at 22:38, David Rowley <dgrowleyml@gmail.com> wrote:
> I could do with a 2nd opinion about if we should just adjust the
> maximum value for the autovacuum_work_mem GUC to 1GB in master.
>
> I'm also not sure if since we'd not backpatch the GUC max value
> adjustment if we need to document the upper limit in the manual.

I was just looking at this again and I see that GIN indexes are able
to use more than 1GB of memory during VACUUM. That discovery makes me
think having the docs say that vacuum cannot use more than 1GB of
memory is at best misleading and more likely just incorrect.

Right now I'm considering if it might just be better to revert
ec34040af and call it quits here.

David