Markus Schiltknecht <markus@bluegap.ch> writes:
>> Since Vacuum process is going to
>> have much more information on what has happened in the database,
> Why should that be? IMO, collecting the information at transaction time
> can give you exactly the same information, if not more or better
> information.
Well, one of the principal arguments for having VACUUM at all is that it
off-loads required maintenance effort from foreground transaction code
paths. I'm not really going to be in favor of solutions that put more
work into the transaction code paths (HOT already did more of that than
I would like :-(). OTOH, I agree that scanning the WAL log doesn't
really sound like something well-matched to this problem either.
regards, tom lane