Horton

Re: query produces 1 GB temp file

Greg Stark <gsstark@mit.edu>

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From: Greg Stark <gsstark@mit.edu>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Greg Stark <gsstark@mit.edu>, Dirk Lutzebaeck <lutzeb@aeccom.com>, pgsql-performance@postgresql.org
Date: 2005-02-05T22:50:13Z
Lists: pgsql-performance 
Tom Lane <tgl@sss.pgh.pa.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