Alfred Perlstein <bright(at)wintelcom(dot)net> writes:
> And since we're sorta on the topic of IO, I noticed that it looks
> like (at least in 7.0.3) that vacuum and certain other routines
> read files in reverse order.
Vacuum does that because it's trying to push tuples down from the end
into free space in earlier blocks. I don't see much way around that
(nor any good reason to think that it's a critical part of vacuum's
performance anyway). Where else have you seen such behavior?
regards, tom lane