Re: query produces 1 GB temp file

From: Greg Stark <gsstark(at)mit(dot)edu>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Greg Stark <gsstark(at)mit(dot)edu>, Dirk Lutzebaeck <lutzeb(at)aeccom(dot)com>, pgsql-performance(at)postgresql(dot)org
Subject: Re: query produces 1 GB temp file
Date: 2005-02-05 22:50:13
Message-ID: 87mzuik4ey.fsf@stark.xeocode.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> It was 700k rows to sort, not 22k.

Oops, missed that.

> > The temporary table does need to store three copies of the records at
> > a given time, but still it sounds like an awful lot.
>
> Huh?

Am I wrong? I thought the disk sort algorithm was the polyphase tape sort from
Knuth which is always reading two tapes and writing to a third.

--
greg

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Tom Lane 2005-02-05 23:01:03 Re: query produces 1 GB temp file
Previous Message Tom Lane 2005-02-05 22:41:24 Re: query produces 1 GB temp file