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From: David Rowley <dgrowleyml@gmail.com>
Date: Thu, 30 Oct 2025 23:36:25 +1300
Message-ID: 
 <CAApHDvohuOypudeuj7nVb9XCyg=u2JR2j00j4zYPGzBjn78piA@mail.gmail.com>
Subject: Re: another autovacuum scheduling thread
To: wenhui qiu <qiuwenhuifx@gmail.com>
Cc: Nathan Bossart <nathandbossart@gmail.com>,
 Sami Imseih <samimseih@gmail.com>,
	Robert Haas <robertmhaas@gmail.com>,
 Jeremy Schneider <schneider@ardentperf.com>,
	pgsql-hackers@postgresql.org
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On Thu, 30 Oct 2025 at 19:48, wenhui qiu <qiuwenhuifx@gmail.com> wrote:
>      I think there might be some misunderstanding =E2=80=94 I=E2=80=99m o=
nly suggesting changing
> effective_xid_failsafe_age =3D Max(vacuum_failsafe_age,
>                                  autovacuum_freeze_max_age * 1.05);
> to
> effective_xid_failsafe_age =3D (vacuum_failsafe_age + autovacuum_freeze_m=
ax_age) / 2.0;
> In the current logic, effective_xid_failsafe_age is almost always equal t=
o vacuum_failsafe_age.
> As a result, increasing the vacuum priority only when a table=E2=80=99s a=
ge reaches vacuum_failsafe_age is too late.

I understand your proposal. The autovacuum will trigger for the
wraparound at autovacuum_freeze_max_age, so for autovacuum still not
to have gotten to the table by the time the table is aged at
vacuum_failsafe_age, it means autovacuum isn't working quickly enough
to get through the workload, therefore the problem is with the speed
of autovacuum not the priority of autovacuum.

David