Jean-Samuel Reynaud <reynaud at elma.fr> writes:
> I have a slony cluster of 4 nodes (3 slaves).
> My master database is about 180Gb (df on  /data directory).
> All server are on postgresql 8.1.xx. But I wanted to upgrade one of
> those slave server to postgresql 8.3. 
> So I had made a test upgrade of postgresql on this slave server
> WITHOUT remove/adding node from replication.
>
> I follow this procedure:

This seems rather like "rocket surgery"[1] to me, and not particularly
valuable in providing a solution somehow preferable to the more
mundane approach, which would be to simply...

- Dump schema from the master (as you did)
- Add the 8.3 database as a new node, with new paths
  Slonik: STORE NODE, STORE PATH
- Subscribe the new node to the desired set(s)
  Slonik: SUBSCRIBE SET
- Drop out the 8.1 node that is now unnecessary [2]
  Slonik: DROP NODE
- _Possibly_ adjust the new 8.3 node's configuration so it is on the
  host formerly used by the 8.1 node [3]
  Slonik: STORE PATH + a bit of reconfig in slon.conf

The approach you have described sounds feasible, but I can't be
certain it covers _everything_.  I'd much rather use the above
approach.

Footnotes: 
[1]  rocket surgery
n. a task requiring intelligence or higher education; a difficult undertaking. Subjects: English
Editorial Note: Often used jocularly in negative constructions similar to "It's not rocket surgery."   
Etymological Note: A blend of rocket science and brain surgery.

[2]  Note that you could drop the old node earlier in the process

[3] If you want to have the new 8.3 node be at the same host+port as
the former 8.1 node, I'd suggest dropping the 8.1 node first, so that
you don't need to go through the slightly "rocket surgery-ish"[1]
process of adjusting configurations in various places so that you
shift the location of the 8.3 node after it has been installed.
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Christopher Browne
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