Re: Proposal for background vacuum full/cluster

"Jim C. Nasby" <decibel@decibel.org> writes:
> In a nutshell, my idea is to use the normal transactional/XID code to
> relocate tuples in the heap. Think of doing an UPDATE field=field if you
> could tell update what page to put the new tuple on. Using this
> mechanism, you can move tuples from the end of the heap to pages that
> have free space on them. The dead tuples at the end of the heap could
> then be vacuumed conventionally, and completely empty pages removed by
> that vacuum.

How exactly is this different from what happens now, assuming that you
didn't run out of FSM?
        regards, tom lane