| From: | Nathan Bossart <nathandbossart(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Andres Freund <andres(at)anarazel(dot)de>, pgsql-hackers(at)lists(dot)postgresql(dot)org, "Imseih (AWS), Sami" <simseih(at)amazon(dot)com>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: allow changing autovacuum_max_workers without restarting |
| Date: | 2025-01-07 17:23:47 |
| Message-ID: | Z31jI10tLLd6thfu@nathan |
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| Lists: | pgsql-hackers |
On Mon, Jan 06, 2025 at 10:29:07PM -0500, Tom Lane wrote:
> +1 for simplicity ... but on reflection, what do you think about
> using max_connections / 6? That would keep autovacuum_worker_slots
> at 100 / 6 = 16 for the vast majority of systems. For the worst case
> *BSD machines, we'd select 25 / 6 = 4 which results in consuming one
> more semaphore than where we were yesterday. I'm willing to accept
> that outcome though, since we still have 3 or so to spare.
WFM. I'm kicking myself for not having thought of that...
> Other than the specific magic number, your patch LGTM.
Here's a new version of the patch with some small cosmetic changes
(including more commentary about the formula) and the constant changed to
6. I'll go commit this shortly.
--
nathan
| Attachment | Content-Type | Size |
|---|---|---|
| v3-0001-Lower-default-value-of-autovacuum_worker_slots-in.patch | text/plain | 5.6 KB |
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