From: | Arthur Silva <arthurprs(at)gmail(dot)com> |
---|---|
To: | Jeremy Harris <jgh(at)wizmail(dot)org> |
Cc: | "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: Abbreviated keys for text cost model fix |
Date: | 2015-03-03 03:08:12 |
Message-ID: | CAO_YK0WQvHvtL44oZ5mM01WmSqgqe6zGOD=hYoiUM4Gxvdb1VQ@mail.gmail.com |
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Lists: | pgsql-hackers |
On Mon, Mar 2, 2015 at 8:04 PM, Jeremy Harris <jgh(at)wizmail(dot)org> wrote:
> On 25/02/15 00:32, Jeremy Harris wrote:
> > On 23/02/15 16:40, Tomas Vondra wrote:
> >> On 22.2.2015 22:30, Peter Geoghegan wrote:
> >>> You should try it with the data fully sorted like this, but with one
> >>> tiny difference: The very last tuple is out of order. How does that
> >>> look?
> >
> > If this case is actually important, a merge-sort can take
> > significant advantage of the partial order:
>
> Presumably it is not, as nobody commented
> on the alleged 20 or 30x speedup.
>
>
>
>
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Does it always perform mergesort instead of quicksort when enabled?
Seems like the case for a hybrid sort (like timsort). I know there was some
talk to replace quicksort with timsort back in 2012 but it was a deadend at
the time.
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