Re: [PERFORM] A Better External Sort? - Mailing list pgsql-hackers

From Tom Lane
Subject Re: [PERFORM] A Better External Sort?
Date
Msg-id 25130.1128628658@sss.pgh.pa.us
Whole thread Raw
In response to Re: [PERFORM] A Better External Sort?  (Martijn van Oosterhout <kleptog@svana.org>)
Responses Re: [PERFORM] A Better External Sort?  (Alvaro Herrera <alvherre@alvh.no-ip.org>)
Re: [PERFORM] A Better External Sort?  (Martijn van Oosterhout <kleptog@svana.org>)
List pgsql-hackers
Martijn van Oosterhout <kleptog@svana.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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