Re: PoC: Partial sort

From: Alexander Korotkov <aekorotkov(at)gmail(dot)com>
To: Marti Raudsepp <marti(at)juffo(dot)org>
Cc: Robert Haas <robertmhaas(at)gmail(dot)com>, Andreas Karlsson <andreas(at)proxel(dot)se>, David Rowley <dgrowleyml(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>, Andres Freund <andres(at)2ndquadrant(dot)com>, Martijn van Oosterhout <kleptog(at)svana(dot)org>
Subject: Re: PoC: Partial sort
Date: 2014-02-10 18:59:48
Message-ID: CAPpHfdsHVEkg4p7P5V5uB6FeEjCKGc0hci4TZ9_kQCnHcvO5Kw@mail.gmail.com
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On Mon, Feb 10, 2014 at 2:33 PM, Marti Raudsepp <marti(at)juffo(dot)org> wrote:

> On Sun, Feb 9, 2014 at 7:37 PM, Alexander Korotkov <aekorotkov(at)gmail(dot)com>
> wrote:
> > This is not only place that worry me about planning overhead. See
> > get_cheapest_fractional_path_for_pathkeys. I had to estimate number of
> > groups for each sorting column in order to get right fractional path.
>
> AFAICT this only happens once per plan and the overhead is O(n) to the
> number of pathkeys? I can't get worried about that, but I guess it's
> better to test anyway.
>
> PS: You didn't answer my questions about splitting the patch. I guess
> I'll have to do that anyway to run the tests.
>

Done. Patch is splitted.

------
With best regards,
Alexander Korotkov.

Attachment Content-Type Size
partial-sort-basic-1.patch.gz application/x-gzip 14.9 KB
partial-sort-merge-1.patch.gz application/x-gzip 2.9 KB

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