Re: query produces 1 GB temp file - Mailing list pgsql-performance

From Tom Lane
Subject Re: query produces 1 GB temp file
Date
Msg-id 190.1107644463@sss.pgh.pa.us
Whole thread Raw
In response to Re: query produces 1 GB temp file  (Greg Stark <gsstark@mit.edu>)
List pgsql-performance
Greg Stark <gsstark@mit.edu> writes:
> 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.

It is a polyphase sort, but we recycle the input "tapes" as fast as we
use them, so that the maximum disk space usage is about as much as the
data volume to sort.

            regards, tom lane

pgsql-performance by date:

Previous
From: Greg Stark
Date:
Subject: Re: query produces 1 GB temp file
Next
From: John A Meinel
Date:
Subject: Re: query produces 1 GB temp file