Re: Merge algorithms for large numbers of "tapes"

From: "Luke Lonergan" <llonergan(at)greenplum(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Simon Riggs" <simon(at)2ndquadrant(dot)com>
Cc: pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: Merge algorithms for large numbers of "tapes"
Date: 2006-03-08 03:53:13
Message-ID: C0339529.1EB93%llonergan@greenplum.com
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Tom,

> fewer passes when T is large. Do you want to try that?

Two passes is the state-of-the-practice on external disk sorts.

If we¹re looking to replace the tape sort approach, I would hope for a two
pass approach, with the merge pass avoided in the case of unidirectional
access.

- Luke

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