The O_DIRECT flag has been added in FreeBSD 4.4 (386 & Alpha) also.  From
the release notes:

Kernel Changes

The O_DIRECT flag has been added to open(2) and fcntl(2). Specifying this
flag for open files will attempt to minimize the cache effects of reading
and writing.


See: http://www.freebsd.org/releases/4.4R/relnotes-i386.html


Wed, 26 Sep 2001 10:30:17 +0800
"Christopher Kings-Lynne" <chriskl@familyhealth.com.au>
O_DIRECT
> The O_DIRECT flag has been added in FreeBSD 4.4 (386 & Alpha) also.  From
> the release notes:
> 
> Kernel Changes
> 
> The O_DIRECT flag has been added to open(2) and fcntl(2). Specifying this
> flag for open files will attempt to minimize the cache effects of reading
> and writing.

I wonder if using this for WAL would be good.

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 853-3000
  +  If your life is a hard drive,     |  830 Blythe Avenue
  +  Christ can be your backup.        |  Drexel Hill, Pennsylvania 19026

Thu, 27 Sep 2001 21:13:02 -0400 (EDT)
Bruce Momjian <pgman@candle.pha.pa.us>
Re: O_DIRECT