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

From Greg Stark
Subject Re: query produces 1 GB temp file
Date
Msg-id 87mzuik4ey.fsf@stark.xeocode.com
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In response to Re: query produces 1 GB temp file  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: query produces 1 GB temp file
List 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

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