Re: [HACKERS] A Better External Sort?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Martijn van Oosterhout <kleptog(at)svana(dot)org>
Cc: Ron Peacetree <rjpeace(at)earthlink(dot)net>, "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org, pgsql-performance(at)postgresql(dot)org
Subject: Re: [HACKERS] A Better External Sort?
Date: 2005-10-06 19:57:38
Message-ID: 25130.1128628658@sss.pgh.pa.us
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Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
> Indeed, one of the things on my list is to remove all the lseeks in
> favour of pread. Halving the number of kernel calls has got to be worth
> something right? Portability is an issue ofcourse...

Being sure that it's not a pessimization is another issue. I note that
glibc will emulate these functions if the kernel doesn't have them;
which means you could be replacing one kernel call with three.

And I don't think autoconf has any way to determine whether a libc
function represents a native kernel call or not ...

regards, tom lane

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