Re: polyphase merge?

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Don Marvick <donmarvick(at)gmail(dot)com>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: polyphase merge?
Date: 2009-02-04 15:20:46
Message-ID: 2316.1233760846@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Don Marvick <donmarvick(at)gmail(dot)com> writes:
> Since nobody replied, I would give it a try. I am going to implement the
> merge pattern described in Knuth Page 365 (5.4.9), essentially it is as
> follow:
> - create initial runs using replacement selection (basically this is as in
> the current implementation)
> - add enough dummy runs of size 0 so that the number of sorted run minus one
> can be divided by k-1 (k is merge fan in)
> - repetitively merge k smallest runs until only 1 run left

How is this better than, or even different from, what is there now?

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Rick Vernam 2009-02-04 15:24:26 Re: LIMIT NULL
Previous Message Jonah H. Harris 2009-02-04 15:19:02 Re: add_path optimization