Date: Fri, 30 May 2014 17:25:26 -0400
From: Bruce Momjian <bruce@momjian.us>
To: Andres Freund <andres@2ndquadrant.com>
Cc: PostgreSQL Bugs <pgsql-bugs@postgresql.org>,
 Alvaro Herrera <alvherre@2ndquadrant.com>
Subject: Re: pg_upgrade < 9.3 -> >=9.3 misses a step around
 multixacts
Message-ID: <20140530212526.GT28490@momjian.us>
References: <20140530121631.GE25431@alap3.anarazel.de>
 <20140530132916.GM28490@momjian.us>
 <20140530133244.GG25431@alap3.anarazel.de>
 <20140530150006.GP28490@momjian.us>
 <20140530151317.GB1220@awork2.anarazel.de>
 <20140530203515.GS28490@momjian.us>
 <20140530210353.GI30516@awork2.anarazel.de>
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On Fri, May 30, 2014 at 11:03:53PM +0200, Andres Freund wrote:
> On 2014-05-30 16:35:15 -0400, Bruce Momjian wrote:
> > On Fri, May 30, 2014 at 05:13:17PM +0200, Andres Freund wrote:
> > > It'd need to be clusters that used more multixacts than fit onto two
> > > slru offsets/ segments in < 9.2. Otherwise things will probably just
> > > continue to work because there's no hole.
> > 
> > Do you mean <= 9.2 here for the old cluster?
> 
> yes.
> 
> > Multi-xacts were added in 9.3:
> 
> That's not really correct. They were added in 8.2 or something...
> 
> >         commit 0ac5ad5134f2769ccbaefec73844f8504c4d6182
> >         Author: Alvaro Herrera <alvherre@alvh.no-ip.org>
> >         Date:   Wed Jan 23 12:04:59 2013 -0300
> > 
> >             Improve concurrency of foreign key locking
> 
> That just expanded the usage to also be able to track updated rows.

I guess I meant the new multixacts file format was in 9.3.

-- 
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + Everyone has their own god. +


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