Date: Mon, 17 Aug 2020 16:09:40 -0400
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Peter Geoghegan <pg@bowt.ie>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>,
	Robert Haas <robertmhaas@gmail.com>,
	Thomas Munro <thomas.munro@gmail.com>,
	Daniel Gustafsson <daniel@yesql.se>,
	"Jonathan S. Katz" <jkatz@postgresql.org>,
	Alexander Korotkov <a.korotkov@postgrespro.ru>,
	PostgreSQL Hackers <pgsql-hackers@postgresql.org>,
	Bruce Momjian <bruce@momjian.us>,
	David Rowley <dgrowleyml@gmail.com>
Subject: Re: Improving connection scalability: GetSnapshotData()
Message-ID: <20200817200940.GA8323@alvherre.pgsql>
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On 2020-Aug-16, Peter Geoghegan wrote:

> On Sun, Aug 16, 2020 at 2:11 PM Andres Freund <andres@anarazel.de> wrote:
> > For the first, one issue is that there's no obviously good candidate for
> > an uninitialized xid. We could use something like FrozenTransactionId,
> > which may never be in the procarray. But it's not exactly pretty.
> 
> Maybe it would make sense to mark the fields as inaccessible or
> undefined to Valgrind. That has advantages and disadvantages that are
> obvious.

... and perhaps making Valgrind complain about it is sufficient.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services