Re: Allowing WAL fsync to be done via O_SYNC

Alfred Perlstein <bright@wintelcom.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