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

From: Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>
To: Zeugswetter Andreas ADI SD <ZeugswetterA(at)spardat(dot)at>
Subject: Re: [SPAM?] Re: Asynchronous I/O Support
Date: 2006-10-24 19:53:23
Message-ID: 453E6F33.1080104@cheapcomplexdevices.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
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.

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Simon Riggs 2006-10-24 19:54:30 Re: New CRC algorithm: Slicing by 8
Previous Message Gregory Stark 2006-10-24 19:42:51 Re: New CRC algorithm: Slicing by 8