| From: | Qingqing Zhou <zhouqq(at)cs(dot)toronto(dot)edu> |
|---|---|
| To: | Neil Conway <neilc(at)samurai(dot)com> |
| Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Which qsort is used |
| Date: | 2005-12-12 17:32:14 |
| Message-ID: | Pine.LNX.4.58.0512121225550.20753@eon.cs |
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| Thread: | |
| Lists: | pgsql-hackers |
On Mon, 12 Dec 2005, Neil Conway wrote:
>
> 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.
>
For qsort, due to its simple usage, I think simulation test should be
enough. But we have to consider many situations like cardinality, data
distribution etc. Maybe not easy to find real world queries providing so
many variations.
> 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
>
Ooops, more interesting than the thread itself ;-)
Regards,
Qingqing
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