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From: Shinya Kato <shinya11.kato@gmail.com>
Date: Wed, 3 Jun 2026 10:24:29 +0900
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Subject: Re: Report oldest xmin source when autovacuum cannot remove tuples
To: Scott Ray <scott@scottray.io>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>, laurenz.albe@cybertec.at,
 japinli@hotmail.com,
	qiuwenhuifx@gmail.com, samimseih@gmail.com,
	pgsql-hackers@lists.postgresql.org
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On Wed, Jun 3, 2026 at 10:05=E2=80=AFAM Scott Ray <scott@scottray.io> wrote=
:
> I've been working on a view like this.  It shows the horizon
> contribution for each backend, prepared xact, replication slot, and
> HSF walsender, broken down by class.  It also shows - for each
> contributor - how the horizon would shift if that holder were
> removed.
>
> Shinya said [1] that we could have a view in the future.  We could
> have both the logging and the view call a single function that reads
> the procArray and other sources to gather the horizon information.  I
> think the logging and the view would complement each other.
>
> Should I start another thread?

My mild preference would be to keep the discussion on this thread,
since the shared function design is central to both the log and the
view and may be easier to keep aligned in one place. That said, I'm
not strongly attached to that, so please pick whichever feels more
convenient.


--=20
Best regards,
Shinya Kato
NTT OSS Center