Michael Guerin <guerin(at)rentec(dot)com> writes:
> You're suggesting to zero out the block in the underlying table files,
> or creating the missing pg_clog file and start filling with zero's?
The former. Making up clog data is unlikely to help --- the bad xmin is
just the first symptom of what's probably more widespread corruption in
the table page. If you want, once you've identified the page containing
the problem, use "pg_filedump -i -f" to dump out that page and we can
have a look to see just how bad it is.
regards, tom lane