public inbox for [email protected]
help / color / mirror / Atom feedFrom: Nathan Bossart <[email protected]>
To: David Rowley <[email protected]>
Cc: Sami Imseih <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Robert Treat <[email protected]>
Cc: Jeremy Schneider <[email protected]>
Cc: [email protected]
Subject: Re: another autovacuum scheduling thread
Date: Wed, 18 Mar 2026 11:09:31 -0500
Message-ID: <abrOO8GCgkhMXvcq@nathan> (raw)
In-Reply-To: <CAApHDvqHXYCb=x0hHeR1e21ksqFNk4q3_zoPk6V-LLu0VL491Q@mail.gmail.com>
References: <abAzhNqs5F8sJDdm@nathan>
<abBEiOICOdbbhsEI@nathan>
<CAA5RZ0seLxDmH9UftUA3vS8DrW+7T9HV5XK8yAuQxA8BaRkg2g@mail.gmail.com>
<CAA5RZ0vfhAnFBp4HrBQc+ALaJMx6vCvMtnBi39ST_4nH9PZEjA@mail.gmail.com>
<abGP87A3JPIXDG2I@nathan>
<CAA5RZ0tWonKY=E5U51i-J8s2EcRoLqtUQyWv+pQ4_rjFKSn+AA@mail.gmail.com>
<abGmNAVIPSqX124E@nathan>
<CAA5RZ0sZE-gfJ0c9HJkOk9XeFQwZL2wuJwrtOX+ZfUBLDcpFMA@mail.gmail.com>
<abMR6MQGQyyKWep4@nathan>
<CAApHDvqHXYCb=x0hHeR1e21ksqFNk4q3_zoPk6V-LLu0VL491Q@mail.gmail.com>
On Wed, Mar 18, 2026 at 12:06:34PM +1300, David Rowley wrote:
> I think it would have been better to have done this about 3 months
> ago, but I think it's probably still fine to do now. Feature freeze is
> still quite a long way from release. I do expect that the most likely
> time that someone would find issues with this change would be during
> beta or RC, as that's when people would give PostgreSQL production
> workloads to try out. During the dev cycle, I expect it's *mostly*
> just hackers giving the database toy workloads in a very targeted way
> to something specific that they're hacking on. Anyway, now since
> you've added the GUCs to control the weights, there's a way for users
> to have some influence, so at least there's an escape hatch.
Thanks for chiming in.
> I think the GUCs are probably a good idea. I expect the most likely
> change that people might want to make would be to raise the priority
> of analyze over vacuum since that's often much faster to complete. We
> know that some workloads are very sensitive to outdated statistics.
>
> On the other hand, we shouldn't be taking adding 5 new autovacuum GUCs
> lightly as there are already so many. If we are going to come up with
> something better than this in a few years then it could be better to
> wait to reduce the pain of having to remove GUCs in the future. I
> don't personally have any better ideas, so I'd rather see it go in
> than not.
Yeah, adding these GUCs feels a bit like etching in stone, but if folks
want configurability, and nobody has better ideas, I'm not sure what else
to do.
> I didn't look at the patch in detail, but noticed that you might want
> to add a "See Section N.N.N for more information." to the new GUCs to
> link to the text you've added on how they're used.
Good idea. I've added that.
> Do you think it's worth making the call to
> list_sort(tables_to_process, TableToProcessComparator) conditional on
> a variable set like: sort_required |= (score != 0.0);? I recall that
> someone had concerns that the actual sort itself could add overhead.
I don't think it's necessary. I tested sorting 1M and 10M tables with
randomly generated scores (on my MacBook, with assertions enabled). The
former took ~150 milliseconds, and the latter took ~1770 milliseconds. I
suspect there are far bigger problems to worry about if you have anywhere
near that many tables.
--
nathan
view thread (143+ messages) latest in thread
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], [email protected], [email protected]
Subject: Re: another autovacuum scheduling thread
In-Reply-To: <abrOO8GCgkhMXvcq@nathan>
* 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