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Date: Tue, 16 Oct 2007 14:21:37 -0400
From: Robert Treat <xzilla@users.sourceforge.net>
Subject: Re: Slony for upgrades
In-reply-to: <200710160538.l9G5c9k19182@momjian.us>
To: pgsql-docs@postgresql.org
Cc: Bruce Momjian <bruce@momjian.us>, Jeff Frost <jeff@frostconsultingllc.com>
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On Tuesday 16 October 2007 01:38, Bruce Momjian wrote:
> Jeff Frost wrote:
> > On Mon, 15 Oct 2007, Bruce Momjian wrote:
> > > Seems we didn't have any mention of Slony for upgrades in the migration
> > > section, so I added it:
> > >
> > >  <para>
> > >   It is also possible to use <productname>Slony</> to create a slave
> > >   server with the updated version of <productname>PostgreSQL</>.  The
> > >   slave can be on the same computer or a different computer.  Once it
> > >   has synced up with the master server (running the older version of
> > >   <productname>PostgreSQL</>), you can switch masters and make the
> > > slave the master and shut down the older database instance.  Such a
> > > switch-over results in only several minutes of downtime for an upgrade.
> > > </para>
> >
> > Bruce, do you think we should say several minutes of downtime?  It's been
> > my experience that the downtime is usually measurable in seconds.  I
> > don't think I've ever had a switchover take more than 1 minute.
> >
> > Excellent catch and good work by the way!
>
> Thanks, changed to seconds.  I thought someone told me <5 minutes a
> while ago but I might have been mistaken.

I might question the strict reference to Slony here. AIUI you could do the 
same thing with Bucardo and a couple of other replication solutions as well.  

-- 
Robert Treat
Build A Brighter LAMP :: Linux Apache {middleware} PostgreSQL