Message-ID: <8a9d8030ebf1b3b39cc3bcf277946dc54dec4e50.camel@cybertec.at>
Subject: Re: Add "io worker" as backend_type to the pg_stat_activity
 documentation
From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Michael Paquier <michael@paquier.xyz>
Cc: Fujii Masao <masao.fujii@gmail.com>, pgsql-docs@lists.postgresql.org
Date: Wed, 22 Jul 2026 07:36:14 +0200
In-Reply-To: <al_wOWrsHfB65Zbk@paquier.xyz>
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On Wed, 2026-07-22 at 07:18 +0900, Michael Paquier wrote:
> On Tue, Jul 21, 2026 at 09:04:15PM +0200, Laurenz Albe wrote:
> > You are right.  Here is patch v3 with a completed list; I hope I didn't
> > forget anything.
>=20
> I am counting 23 entries.  I don't see anything forgotten on top of my
> mind, and we are indeed missing a lot of new entries.

Great.

> > +         <para>
> > +          <literal>autovacuum worker</literal>: A background process r=
unning
> > +          <command>VACUUM</command> or <command>ANALYZE</command> on a=
 single
> > +          table.
> > +         </para>
>=20
> Also active when autovacuum =3D on?

Well, anti-wraparound autovacuum workers can also run if autovacuum =3D off=
.
Also, autovacuum workers only indirectly depend on the GUC.
I figured that if I say that the autovacuum launcher depends on the GUC and
launches autovacuum workers, the indirect dependency should be obvious.

> > +         <para>
> > +          <literal>walreceiver</literal>: The background process that =
receives
> > +          WAL records from a WAL sender, active in streaming replicati=
on
> > +          standby mode.
> > +         </para>
>=20
> We can only have one of these.

That's why I said "*the* background process".
Or did I miss your point?

> > +        </listitem>
> > +        <listitem>
> > +         <para>
> > +          <literal>walsender</literal>: A background process that send=
s WAL
> > +          records to receivers (during streaming replication) or decod=
es WAL
> > +          and sends the decoded information (during logical replicatio=
n).
> > +         </para>
> > +        </listitem>
>=20
> No mention of the max_wal_senders dependency?  Perhaps not worth
> mentioning, still..

I don't want to mention all GUCs that have an influence on the processes,
and I feel that my descriptions are already pretty long.

If I mention that dependency, I should also mention that max_connections
limits the number of backends, and so on...

Yours,
Laurenz Albe