Gregory Stark <stark(at)enterprisedb(dot)com> writes:
> Incidentally the visibility bugs are indeed entirely fixed in 8.3. In 8.2 and
> before cluster and alter table rewrites can both cause tuples to not appear
> for transactions which were started before the cluster or alter table such as
> a long-running pg_dump.
AFAIK that's true only for CLUSTER, not ALTER TABLE. There would be a
bunch of logical inconsistencies in altering rows and then pretending
you hadn't.
regards, tom lane