Thanks for your excellent reply.

On Thu, 2007-01-11 at 00:18 -0500, Jan Wieck wrote:
> On 1/10/2007 10:55 PM, Adam Cassar wrote:
> > Hello,
> > 
> > We are currently running slony successfully in a mixed PG environment
> > (v8 and v8.1).
> > 
> > With the release of PG v8.2 we want to upgrade all servers in our
> > cluster to v8.2
> > 
> > I thought this would be quite simple - just dump and restore the db and
> > everything should work....
> 
> That assumption was quite wrong. That is not the way how to upgrade a 
> Slony cluster.
> 
> The database schema of your subscriber nodes (slaves) is in an 
> inconsistent state from PostgreSQL's point of view. I am planning to get 
> rid of this problem in the future, but it will be some time before it 
> can be fixed. That means, that you cannot dump and restore a subscriber.
> 
> If you have the luxury to take an outage long enough to
> 
>      1.) uninstall slony completely
>      2.) dump, upgrade PostgreSQL and restore the master
>      3.) throw away and install new PostgreSQL version on all slaves
>      4.) rebuild the entire slony cluster
> 
> do that.
> 
> Unfortunately not everyone has that luxury. If you are among those 
> unfortunate people, here are the 12 pains of Christmas, Slony gave to you:
> 
>      1.) upgrade the cluster to the latest slony production release
>      2.) Make your designated Backup node a leaf node
>      3.) DROP that designated Backup node.
>      4.) throw away and install new PostgreSQL version on that node.
>      5.) STORE NODE for it and go through the full subscription process.
>      6.) wait until it is completely in sync.
>      7.) make it the only direct subscriber of the master, with all
>          other nodes being cascaded from it (directly or sub-cascaded).
>      8.) Switchover to the designated backup.
>      9.) Drop the old master (which is now a subscriber).
>     10.) Upgrade old master to an empty, new PostgreSQL version.
>     11.) Subscribe it (again, wait until complete and cought up).
>     12.) Switch back and reshape the cluster as needed.
> 
> The reason why this is so ugly and painfull is entirely that it is 
> impossible to dump and restore a subscriber any way, that restores the 
> system catalog into it's slony-corrupted state. That is why I am 
> currently focused entirely on fixing that problem. Things would be a lot 
> easier without that.
> 
> 
> Jan
> 
-- 
Adam Cassar
ICT Manager
NetRegistry Pty Ltd
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