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Re: Randomisation for ensuring nlogn complexity in quicksort - Mailing list pgsql-hackers

From Peter Geoghegan
Subject Re: Randomisation for ensuring nlogn complexity in quicksort
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Msg-id CAM3SWZRHi=T2-xPLg4aANHTPqoqkKR3jUctomxHD3D0k-5Zt9w@mail.gmail.com
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In response to Re: Randomisation for ensuring nlogn complexity in quicksort  (Robert Haas <robertmhaas@gmail.com>)
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On Mon, Jul 1, 2013 at 12:32 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> I have been reading the recent discussion and was researching a bit, and I think that we should really go with the
ideaof randomising the input data(if it is not completely presorted), to ensure that we do not get quadratic
complexity.
>
> That doesn't ensure any such thing.  It just makes it less likely.
> But we have existing guards that also make that unlikely, so I'm not
> sure what we'd be gaining.

+1

-- 
Peter Geoghegan

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