Horton

Re: PoC: Partial sort

Marti Raudsepp <marti@juffo.org>

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From: Marti Raudsepp <marti@juffo.org>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Andreas Karlsson <andreas@proxel.se>, David Rowley <dgrowleyml@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Andres Freund <andres@2ndquadrant.com>, Martijn van Oosterhout <kleptog@svana.org>
Date: 2014-02-10T10:33:27Z
Lists: pgsql-hackers 
On Sun, Feb 9, 2014 at 7:37 PM, Alexander Korotkov <aekorotkov@gmail.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.

Regards,
Marti

Commits

  1. Implement Incremental Sort

  2. Improve memory management for external sorts.