Horton

Re: PoC: Partial sort

Peter Geoghegan <pg@heroku.com>

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From: Peter Geoghegan <pg@heroku.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Andreas Karlsson <andreas@proxel.se>, David Rowley <dgrowleyml@gmail.com>, Marti Raudsepp <marti@juffo.org>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Andres Freund <andres@2ndquadrant.com>, Martijn van Oosterhout <kleptog@svana.org>
Date: 2016-04-08T19:09:12Z
Lists: pgsql-hackers 
On Wed, Mar 30, 2016 at 8:02 AM, Alexander Korotkov
<aekorotkov@gmail.com> wrote:
> Hmm... I'm not completely agree with that. In typical usage partial sort
> should definitely use quicksort.  However, fallback to other sort methods is
> very useful.  Decision of partial sort usage is made by planner.  But
> planner makes mistakes.  For example, our HashAggregate is purely in-memory.
> In the case of planner mistake it causes OOM.  I met such situation in
> production and not once.  This is why I'd like partial sort to have graceful
> degradation for such cases.

I think that this should be moved to the next CF, unless a committer
wants to pick it up today.


-- 
Peter Geoghegan

Commits

  1. Implement Incremental Sort

  2. Improve memory management for external sorts.