public inbox for [email protected]  

help / color / mirror / Atom feed

From: Laurenz Albe <[email protected]>
To: David Rowley <[email protected]>
Cc: Martín Marqués <[email protected]>
Cc: PostgreSQL Developers <[email protected]>
Subject: Re: Update maintenance_work_mem/autovacuum_work_mem to reflect the 1GB limitation with VACUUM
Date: Fri, 02 Jul 2021 14:40:52 +0200
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAApHDvrSDxi2jvStdi4vnrD3JjMffSkEZhK8C3-NsLV+CFhL8A@mail.gmail.com>
References: <CABeG9LsZ2ozUMcqtqWu_-GiFKB17ih3p8wBHXcpfnHqhCnsc7A@mail.gmail.com>
	<[email protected]>
	<[email protected]>
	<CAApHDvrSDxi2jvStdi4vnrD3JjMffSkEZhK8C3-NsLV+CFhL8A@mail.gmail.com>

On Fri, 2021-07-02 at 23:31 +1200, David Rowley wrote:
> I had a look at the patch in [1] and I find it a bit weird that we'd
> write the following about autovacuum_work_mem in our docs:
> 
> +       <para>
> +        Note that <command>VACUUM</command> has a hard-coded limit of 1GB
> +        for the amount of memory used, so setting
> +        <varname>autovacuum_work_mem</varname> higher than that has no effect.
> +       </para>
> 
> Since that setting is *only* used for auto vacuum, why don't we just
> limit the range of the GUC to 1GB?
> 
> Of course, it wouldn't be wise to backpatch the reduced limit of
> autovacuum_work_mem as it might upset people who have higher values in
> their postgresql.conf when their database fails to restart after an
> upgrade. I think what might be best is just to reduce the limit in
> master and apply the doc patch for just maintenance_work_mem in all
> supported versions. We could just ignore doing anything with
> autovacuum_work_mem in the back branches and put it down to a
> historical mistake that can't easily be fixed now.
> 
> I've attached what I came up with.
> 
> What do you think?
> 
> [1] https://www.postgresql.org/message-id/514fe5ce4714b7b33cb0a611f0c7b72df413bef5.camel%40cybertec.at

I think that is much better.
I am fine with that patch.

Yours,
Laurenz Albe

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected]
  Subject: Re: Update maintenance_work_mem/autovacuum_work_mem to reflect the 1GB limitation with VACUUM
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox