Re: [SPAM?] Re: Asynchronous I/O Support

Ron Mayer <rm_pg@cheapcomplexdevices.com>

From: Ron Mayer <rm_pg@cheapcomplexdevices.com>
To: Zeugswetter Andreas ADI SD <ZeugswetterA@spardat.at>
Date: 2006-10-24T19:53:23Z
Lists: pgsql-hackers
Zeugswetter Andreas ADI SD wrote:
> POSIX_FADV_WILLNEED definitely sounds very interesting, but:
> 
> I think this interface was intended to hint larger areas (megabytes).
> But the "wishful" thinking was not to hint seq scans, but to advise
> single 8k pages.

Surely POSIX_FADV_SEQUENTIAL is the one intended to hint seq scans,
and POSIX_FADV_RANDOM to hint random access.  No?

ISTM, _WILLNEED seems just right for small random-access blocks.



Anyway, for those who want to see what they do in Linux,
  http://www.gelato.unsw.edu.au/lxr/source/mm/fadvise.c
Pretty scary that Bruce said it could make older linuxes
dump core - there isn't a lot of code there.