| From: | Peter Geoghegan <pg(at)heroku(dot)com> |
|---|---|
| To: | Greg Stark <stark(at)mit(dot)edu> |
| Cc: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Simon Riggs <simon(at)2ndquadrant(dot)com> |
| Subject: | Re: Using quicksort for every external sort run |
| Date: | 2015-12-09 02:44:29 |
| Message-ID: | CAM3SWZTC_LkGFxOaHfsFv9mZdtx8YXhYYyGc4kJkCnAufPkjqw@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Tue, Dec 8, 2015 at 6:39 PM, Greg Stark <stark(at)mit(dot)edu> wrote:
> Fwiw attached are two patches for perusal. One is a trivial patch to
> add the size of the tape to trace_sort output. I guess I'll just apply
> that without discussion.
+1
> The other replaces the selection sort with an
> open coded sort network for cases up to 8 elements. (Only in the perl
> generated qsort for the moment). I don't have the bandwidth to
> benchmark this for the moment but if anyone's interested in trying I
> suspect it'll make a small but noticeable difference. I'm guessing
> 2-5%.
I guess you mean insertion sort. What's the theoretical justification
for the change?
--
Peter Geoghegan
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Etsuro Fujita | 2015-12-09 03:00:02 | Re: Foreign join pushdown vs EvalPlanQual |
| Previous Message | Greg Stark | 2015-12-09 02:39:13 | Re: Using quicksort for every external sort run |