Re: Closing some 8.4 open items

Heikki,

> It's important to distinguish what kind of fadvise we're talking about.
> The bitmap scan code issues hints about individual pages, using
> posix_fadvise(... POSIX_FADV_WILLNEED). For increasing the readahead of
> a sequential scan, you'd want to use POSIX_FADV_SEQUENTIAL. I believe
> the support for the latter is much more widespread than for the former.

OK, so this is potentially useful (pending testing) but it's a different 
feature.  We'll discuss it for 8.5.

The other thing I was going to ask you about is using posix_fadvise as 
an alternative to O_DIRECT for the xlog.  O_DIRECT is, AFAIK, 
linux-only, whereas there are "direct write" fadvise flags which work on 
multiple OSes.

-- 
Josh Berkus
PostgreSQL Experts Inc.
www.pgexperts.com