Andy Dale <andy(dot)dale(at)gmail(dot)com> writes:
> After looking into the the data directory a particular file/oid is around 21
> GB (the oid has 21 files), this OID can then be found in the pg_class table,
> the explanation for the size being that the table has around 12.5 Million
> rows. During the inspection of the data directory I observed another OID
> that is around 8.5GB, but I cannot locate the corresponding entry in the
> pg_class table (even after dumping the table into a file and grep-ing for
> the OID in question).
You should be looking at pg_class.relfilenode, not OID. See
http://www.postgresql.org/docs/8.3/static/storage.html
regards, tom lane