| From: | Mithun Cy <mithun(dot)cy(at)enterprisedb(dot)com> |
|---|---|
| To: | Peter Geoghegan <pg(at)heroku(dot)com> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Jeff Janes <jeff(dot)janes(at)gmail(dot)com>, Simon Riggs <simon(at)2ndquadrant(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com>, Greg S <stark(at)mit(dot)edu> |
| Subject: | Re: Using quicksort for every external sort run |
| Date: | 2016-01-29 12:03:31 |
| Message-ID: | CAD__Ouhz3bu6SRYb3E5_1e2237v5q=RqOeHKDnNt_u530s8c5w@mail.gmail.com |
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| Thread: | |
| Lists: | pgsql-hackers |
On Fri, Jan 29, 2016 at 5:11 PM, Mithun Cy <mithun(dot)cy(at)enterprisedb(dot)com>
wrote
>
>
>
> >I just ran some tests on above patch. Mainly to compare
> >how "longer sort keys" would behave with new(Qsort) and old Algo(RS) for
> sorting.
> >I have 8GB of ram and ssd storage.
>
>
> *Key length 520*
>
>
>
>
> *Number of records* 3200000 6400000 12800000 25600000
>
> 1.7 GB 3.5GB 7 GB 14GB
>
>
>
>
>
> *CASE 1*
>
>
>
> *RS* 23654.677 35172.811 44965.442 106420.155
> *Qsort* 14100.362 40612.829 101068.107 334893.391
>
>
>
>
>
> *CASE 2*
>
>
>
> *RS* 13427.378 36882.898 98492.644 310670.15
> *Qsort* 12475.133 32559.074 100772.531 322080.602
>
>
>
>
>
> *CASE 3*
>
>
>
> *RS* 17202.966 45163.234 122323.299 337058.856
> *Qsort* 12530.726 23343.753 59431.315 152862.837
>
>
>
> *CASE 1* *RS* 128822.735
>
> *Qsort* 90857.496
> *CSAE 2* *RS* *105631.775*
>
> *Qsort* *105938.334*
> *CASE 3* *RS* *152301.054*
>
> *Qsort* *149649.347*
>
>
Sorry forgot to mention above data in table is in unit of ms, returned by
psql client.
--
Thanks and Regards
Mithun C Y
EnterpriseDB: http://www.enterprisedb.com
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