Date: Mon, 9 Feb 2015 15:53:05 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: bkrug <bkrug@usatech.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Avoiding Refreezing XIDs Repeatedly
Message-ID: <20150209185305.GF3391@alvh.no-ip.org>
References: <1423497516487-5837222.post@n5.nabble.com>
 <CAJghg4KAFiFnH6inJ+K7Bfef9bgGYt7E6MM3rkevqiT=Q245HQ@mail.gmail.com>
 <1423507553954-5837247.post@n5.nabble.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <1423507553954-5837247.post@n5.nabble.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Precedence: bulk
Sender: pgsql-performance-owner@postgresql.org

bkrug wrote:
> Matheus de Oliveira wrote
> > It changed in recent versions (9.3 or 9.4, I don't recall exactly which)
> > and moved to tuple header, but what you described is exactly what was
> > done,
> > the xid was 2.
> 
> Should the relfrozenxid of pg_class then equal 2 for very old and already
> vacuumed tables? Because that is not what I am seeing.

No.  The problem is that it's not easy to change the relfrozenxid when
an INSERT/UPDATE command creates a tuple with a non-frozen XID.

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


-- 
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance