From: | "Qingqing Zhou" <zhouqq(at)cs(dot)toronto(dot)edu> |
---|---|
To: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Which qsort is used |
Date: | 2005-12-12 17:09:16 |
Message-ID: | dnkaq4$1lqg$1@news.hub.org |
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Lists: | pgsql-hackers |
"Bruce Momjian" <pgman(at)candle(dot)pha(dot)pa(dot)us> wrote
>
> Are you willing to say that we should always prefer pgport over glibc's
> qsort()?
>
At least for Linux and windows. My test is performed on a dataset ranges
from 10 to 15000000 elements. Each elements contains a 64 bytes garbage
character area and an integer key, which is uniformly distributed from 1 to
RANGE. RANGE takes values from 2 to 2^31. In all cases, our qsort absolutely
wins. Maybe skewed distribution should be tested?
Another interesting thing is that the qsort on RANGE=2 or other small number
in windows is terriblly slow - our version does not have this problem.
The test code could be found here (Note: it mixed with some other
experiements I am doing but might be a good start point to construct your
own tests):
http://www.cs.toronto.edu/~zhouqq/sort.c
Regards,
Qingqing
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