Date: Mon, 19 Jul 2021 17:24:48 -0400
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: jeff.janes@gmail.com, mk@071.ovh, pgsql-bugs@lists.postgresql.org
Subject: Re: BUG #17103: WAL segments are not removed after exceeding
 max_slot_wal_keep_size
Message-ID: <202107192124.kay2nglie2y3@alvherre.pgsql>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <20210719.111318.2042379313472032754.horikyota.ntt@gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/202107192124.kay2nglie2y3%40alvherre.pgsql>
Precedence: bulk

On 2021-Jul-19, Kyotaro Horiguchi wrote:

> Sorry for the mistake.  It seems to me the cause the above is that
> segment removal happens *after* invalidation. Since (at least
> currently) the "slot is invalidated" warning issued only at the time
> just before WAL-removal, we should expect that old segments are gone
> after the checkpoint-ending log, which should be seen after
> WAL-removal.  If not, that shows that there's a bug.
> 
> What do you think about the attached?

Sounds sensible -- I verified the logs for one of the cases that failed
in the buildfarm, and indeed the "checkpoint ended" message appears
after the s2 slot is created, so it should fix the problem.  (I didn't
actually try to reproduce the problem locally, so I didn't verify the
fix any further than ensuring the test still passes.)

Pushed, thanks!

-- 
Álvaro Herrera           39°49'30"S 73°17'W  —  https://www.EnterpriseDB.com/