Re: [PERFORM] A Better External Sort?

On Thu, Oct 06, 2005 at 04:25:11PM -0400, Tom Lane wrote:
> Martijn van Oosterhout <kleptog@svana.org> writes:
> > Are we awfully worried about people still using 2.0 kernels? And it
> > would replace two calls with three in the worst case, we currently
> > lseek before every read.
>
> That's utterly false.

Oops, you're right. I usually strace during a vacuum or a large query
and my screen fills up with:

lseek()
read()
lseek()
read()
...

So didn't wonder if the straight sequential read was optimised. Still,
I think pread() would be a worthwhile improvement, at least for Linux.

--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.