Bruce Momjian <bruce@momjian.us> writes:
> On Wed, Apr 17, 2013 at 01:29:18PM -0400, Tom Lane wrote:
>> But having said that, I'm not sure why this would be pg_upgrade's
>> problem. By definition, we do not want pg_upgrade running around
>> looking at individual data pages. Therefore, whatever we might do
>> about checksum algorithm changes would have to be something that can be
>> managed on-the-fly by the newer server.
> Well, my idea was that pg_upgrade would allow upgrades from old clusters
> with the same checksum algorithm version, but not non-matching ones.
> This would allow the checksum algorithm to be changed and force
> pg_upgrade to fail.
It's rather premature to be defining pg_upgrade's behavior for a
situation that doesn't exist yet, and may very well never exist
in that form. It seems more likely to me that we'd want to allow
incremental algorithm changes, in which case pg_upgrade ought not do
anything about this case anyway.
regards, tom lane