Adam Witney <awitney@sgul.ac.uk> writes:
> This table is only ever COPY'd to from data files, no updates or deletes, if
> I could find out which data file this bit comes from I could just reupload
> that file... Is it possible to tell what the data actually is from the data
> I sent?
You might try dumping the page with "od -c" instead of "-x" and looking
to see if there are any recognizable strings. Also try the same on the
preceding or following pages. Or try dumping what's on the preceding
and following pages, eg
select * from tab where ctid = '(597620,1)';
select * from tab where ctid = '(597620,2)';
...
(run the item number up high enough to be sure you've seen all the live
rows on the page).
To get the file back in a usable state before you add more data, you'll
want to zero the bad block out completely, and then do a VACUUM to see
if there are any other damaged pages.
regards, tom lane