Re: Memory usage during sorting

From: Jeremy Harris <jgh(at)wizmail(dot)org>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Memory usage during sorting
Date: 2012-03-18 15:32:50
Message-ID: 4F660022.5000608@wizmail.org
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On 2012-03-18 15:25, Tom Lane wrote:
> Jeff Janes<jeff(dot)janes(at)gmail(dot)com> writes:
>> On Wed, Mar 7, 2012 at 11:55 AM, Robert Haas<robertmhaas(at)gmail(dot)com> wrote:
>> The problem there is that none of the files can be deleted until it
>> was entirely read, so you end up with all the data on disk twice. I
>> don't know how often people run their databases so close to the edge
>> on disk space that this matters, but someone felt that that extra
>> storage was worth avoiding.
>
> Yeah, that was me, and it came out of actual user complaints ten or more
> years back. (It's actually not 2X growth but more like 4X growth
> according to the comments in logtape.c, though I no longer remember the
> exact reasons why.) We knew when we put in the logtape logic that we
> were trading off speed for space, and we accepted that.

How about a runtime check of disk-free?
--
Jeremy

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