Robert Haas <robertmhaas@gmail.com> writes:
> On the other hand, I can't entirely shake the feeling that adding the
> information into WAL would be more reliable.
That feeling has been nagging at me too. I can't demonstrate that
there's a problem when an ALTER TABLE is in process of rewriting a table
into a new relfilenode number, but I don't have a warm fuzzy feeling
about the reliability of reverse lookups for this. At the very least
it's going to require some hard-to-verify restriction about how we
can't start doing changeset reconstruction in the middle of a
transaction that's doing DDL.
regards, tom lane