MIME-Version: 1.0
References: <20210423204306.5osfpkt2ggaedyvy@alap3.anarazel.de>
 <CAH2-Wz=f2dfc-0BcM5X5ttXTeRNPg+JtxEMCuSZR82a7XHfRkg@mail.gmail.com>
 <20210424002921.pb3t7h6frupdqnkp@alap3.anarazel.de>
 <CAH2-WzkDM7nC+j2b3kB-2w4YkjXmrT+i0ppEcCNwTkpRehKLyQ@mail.gmail.com>
 <CAD21AoBhZrV7zoMGNZJm0h16Zw+UN=+EpWKBOu90zHm3pA4WVw@mail.gmail.com>
 <CAH2-Wz=3UyssRDzcsm-RTApDe_ZPxbb_7MXS37qatXOvw5CH+g@mail.gmail.com>
 <CAD21AoCtjbzAbaYXcvBP2dO=or_weQms0+vZJFbmMPz6PaBAcg@mail.gmail.com>
 <CAD21AoDMFFVfEiRjLO1KH9Kh07yGh7DUuEKd2ZmPXaFm1mViTw@mail.gmail.com>
In-Reply-To: 
 <CAD21AoDMFFVfEiRjLO1KH9Kh07yGh7DUuEKd2ZmPXaFm1mViTw@mail.gmail.com>
From: Peter Geoghegan <pg@bowt.ie>
Date: Mon, 24 May 2021 17:14:36 -0700
Message-ID: 
 <CAH2-WznqVesSxWOejO0WCemEBo5d_g4c11pU=LbO2+o-BMAcYw@mail.gmail.com>
Subject: Re: Testing autovacuum wraparound (including failsafe)
To: Masahiko Sawada <sawada.mshk@gmail.com>
Cc: Andres Freund <andres@anarazel.de>,
 PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Content-Type: text/plain; charset="UTF-8"
Archived-At: 
 <https://www.postgresql.org/message-id/CAH2-WznqVesSxWOejO0WCemEBo5d_g4c11pU%3DLbO2%2Bo-BMAcYw%40mail.gmail.com>
Precedence: bulk

On Tue, May 18, 2021 at 12:10 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> Since there is the condition "vacrel->num_index_scans == 0" we could
> enter the failsafe mode even if the table is less than 4GB, if we
> enter lazy_check_wraparound_failsafe() after executing more than one
> index scan. Whereas a vacuum on the table that is less than 4GB and
> has no index never enters the failsafe mode. I think we can remove
> this condition since I don't see the reason why we don't allow to
> enter the failsafe mode only when the first-time index scan in the
> case of such tables. What do you think?

I'm convinced -- this does seem like premature optimization now.

I pushed a version of the patch that removes that code just now.

Thanks
-- 
Peter Geoghegan