Re: Using quicksort for every external sort run

From: Jeremy Harris <jgh(at)wizmail(dot)org>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Using quicksort for every external sort run
Date: 2015-12-09 18:13:59
Message-ID: 56686F67.4010303@wizmail.org
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

On 09/12/15 00:02, Jeff Janes wrote:
> The second one consumes that giant tape run along with 232 small tape
> runs.

In terms of number of comparisons, binary merge works best when the
inputs are of similar length. I'd assume the same goes for n-ary
merge, but I don't know if comparison count is an issue here.
--
Cheers,
Jeremy

In response to

Browse pgsql-hackers by date

  From Date Subject
Next Message Robert Haas 2015-12-09 18:21:02 Re: parallel joins, and better parallel explain
Previous Message Robert Haas 2015-12-09 17:49:46 Re: Confusing results with lateral references