Greg Stark <gsstark@mit.edu> writes:
> I originally thought you meant if you are repeatedly updating the same record
> within the same transaction. In that case sure you could reuse the space but
> a) only if it's big enough for the new record and b) how often do you really
> do that?
Also, it's not that easy even within a single transaction: you could
have active snapshots inside your xact that can still see the obsoleted
tuple.
regards, tom lane