Robert Treat <xzilla(at)users(dot)sourceforge(dot)net> writes:
> On a similar note I was just wondering if it would be possible to
> mark any of these dead tuples as ready to be reused at transaction
> commit time, since we know that they are dead to any and all other
> transactions currently going on.
I believe VACUUM already knows that xmin = xmax implies the tuple
is dead to everyone.
> This would save you from having to vacuum to get the tuples marked
> ready for reuse.
No; you forgot about reclaiming associated index entries.
regards, tom lane