David Rees wrote:
> On 10/19/07, JP Fletcher <jpfletch at ca.afilias.info> wrote:
>> David Rees wrote:
>>> 1. Stop all slon daemons.
>>> 2. Drop Pg 8.2 node from cluster.
>>> 3. Stop Pg 8.2
>>> 4. Restart Pg 8.3 on the old port
>>> 5. Update slon config for old port.
>>> 6. Update sl_path info how???
>>> 7. Restart slon daemons
>>>
>>> Step 6 is where I get a bit unsure/lost. It looks like there is
>>> connection information stored in the sl_path table and that should be
>>> updated before starting up the slon daemons.
>> What is it that you think should be updated?  When you stop your 8.2
>> instance, and bring up the 8.3 instance on the port formerly occupied by
>> 8.2, the conninfo in sl_path will match the 8.3 instance.
> 
> Right, but the 8.2 instance is node 2, the 8.3 instance is node 3.
> Step 2 includes dropping node 2 from the cluster.
> 
> You could also ignore the fact that node 2 is going away for example,
> and lets just say I wanted to change the port that node 3 is running
> on... what's the "best practice" for doing so?

When we do this sort of thing, we bring down both old and new
postmasters, swap the ports, then restart.  Then we reshape sl_path with
slonik STORE PATH commands.  And we wait to drop the old node until
later.

> 
> Updating sl_path is easy enough (only have 3 databases replicated on
> this test setup, so that is 6 sl_path tables that need updating), I
> just imagined that there would have been a more straight forward way
> since everything else in slony is so straight forward. :-)
> 
> -Dave