Re: PoC: Partial sort

From: Alexander Korotkov <aekorotkov(at)gmail(dot)com>
To: Peter Geoghegan <pg(at)heroku(dot)com>
Cc: Andreas Karlsson <andreas(at)proxel(dot)se>, David Rowley <dgrowleyml(at)gmail(dot)com>, Marti Raudsepp <marti(at)juffo(dot)org>, Robert Haas <robertmhaas(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: 2016-09-13 08:32:51
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On Fri, Apr 8, 2016 at 10:09 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:

> On Wed, Mar 30, 2016 at 8:02 AM, Alexander Korotkov
> <aekorotkov(at)gmail(dot)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.

Patch was rebased to current master.

Alexander Korotkov
Postgres Professional:
The Russian Postgres Company

Attachment Content-Type Size
partial-sort-basic-9.patch application/octet-stream 85.6 KB

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