Zdenek Kotala <Zdenek.Kotala@Sun.COM> writes:
> Tom Lane napsal(a):
>> * Add a "format serial number" column to pg_class, and probably also
>> pg_database. Rather like the frozenxid columns, this would have the
>> semantics that all pages in a relation or database are known to have at
>> least the specified format number.
> I prefer to have latest processed block. InvalidBlockNumber would mean
> nothing is processed and 0 means everything is already reserved. I
> suggest to process it backward. It should prevent to check new
> extended block which will be already correctly setup.
That seems bizarre and not very helpful. In the first place, if we're
driving it off vacuum there would be no opportunity for recording a
half-processed state value. In the second place, this formulation fails
to provide any evidence of *what* processing you completed or didn't
complete. In a multi-step upgrade sequence I think it's going to be a
mess if we aren't explicit about that.
regards, tom lane