Re: Which qsort is used - Mailing list pgsql-hackers

From Neil Conway
Subject Re: Which qsort is used
Date
Msg-id 1134407746.9179.13.camel@localhost.localdomain
Whole thread Raw
In response to Re: Which qsort is used  (Bruce Momjian <pgman@candle.pha.pa.us>)
Responses Re: Which qsort is used  (Qingqing Zhou <zhouqq@cs.toronto.edu>)
Re: Which qsort is used  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
On Mon, 2005-12-12 at 11:50 -0500, Bruce Momjian wrote:
> Are you willing to say that we should always prefer pgport over glibc's
> qsort()?

glibc's qsort is actually implemented via merge sort. I'm not sure why
the glibc folks chose to do that, but as a result, it's not surprising
that BSD qsort beats it for typical inputs. Whether we should go to the
trouble of second-guessing glibc is a separate question, though: it
would be good to see some performance figures for real-world queries.

BTW, Luke Lonergan recently posted some performance results for a fairly
efficient public domain implementation of qsort to the bizgres list:

http://lists.pgfoundry.org/pipermail/bizgres-general/2005-December/000294.html

-Neil




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