RE: GSOC 2018 Project - A New Sorting Routine

Hey Tomas!

I am trying to reproduce the results on my machine. Could you please share the script to generate .ods files?

Regards,
Kefan

From: Tomas Vondra
Sent: July 18, 2018 2:05 AM
To: Andrey Borodin
Cc: Peter Geoghegan; Kefan Yang; PostgreSQL Hackers
Subject: Re: GSOC 2018 Project - A New Sorting Routine

On 07/18/2018 07:06 AM, Andrey Borodin wrote:
> Hi, Tomas!
>
>> 15 июля 2018 г., в 1:20, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com
>> <mailto:tomas(dot)vondra(at)2ndquadrant(dot)com>> написал(а):
>>
>> So I doubt it's this, but I've tweaked the scripts to also set this GUC
>> and restarted the tests on both machines. Let's see what that does.
>
> Do you observe any different results?
>

It did change the CREATE INDEX results, depending on the scale. The full
data is available at [1] and [2], attached is a spreadsheet summary from
the Xeon box.

For the largest scale (1M rows) the regressions for CREATE INDEX queries
mostly disappeared. For 10k rows it still affects CREATE INDEX with a
text column, and the 100k case behaves just like before (so significant
regressions for CREATE INDEX).

I don't have time to investigate this further at the moment, but I'm
still of the opinion that there's little to gain by replacing our
current sort algorithm with this.

[1] https://bitbucket.org/tvondra/sort-intro-sort-xeon/src/master/
[2] https://bitbucket.org/tvondra/sort-intro-sort-i5/src/master/

regards

--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services