Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > Yes, good point about pg_shadow. They don't have databases. How do we
> > get multiple pg_class tables in the same directory? Is the
> > pg_class.relversion file a number like 1,2,3,4, or does it come out of
> > some global counter like oid. If so, we could put them in the same
> > directory.
>
> I think we could get away with insisting that each database store its
> pg_class and friends in a separate tablespace (physically distinct
> directory) from any other database. That gets around the OID conflict.
>
> It's still an open question whether OID+version is better than
> unique-ID for naming files that belong to different versions of the
> same relation. I can see arguments on both sides.
>
I don't stick to unique-ID. My main point has always been the
transactional control of file allocation change.
However *VERSION(_ID)* may be misleading because it couldn't
mean the version of pg_class tuples.
Regards.
Hiroshi Inoue
Inoue@tpf.co.jp