Glen Parker <glenebob(at)nwlink(dot)com> writes:
> How much of a TOAST'd field is actually stored in the main heap table?
> Is there a way to configure that amount?
A pushed-out-of-line value is replaced by a 20-byte pointer structure.
There's no such thing as partially out-of-line. See
http://www.postgresql.org/docs/8.1/static/storage-toast.html
regards, tom lane