Re: Fix around conn_duration in pgbench

Tatsuo Ishii <ishii@sraoss.co.jp>

From: Tatsuo Ishii <ishii@sraoss.co.jp>
To: nagata@sraoss.co.jp
Cc: ishii@sraoss.co.jp, coelho@cri.ensmp.fr, masao.fujii@oss.nttdata.com, asifr.rehman@gmail.com, pgsql-hackers@lists.postgresql.org
Date: 2021-08-31T06:39:18Z
Lists: pgsql-hackers
>> >> > My 0.02€: From a benchmarking perspective, ISTM that it makes sense to
>> >> > include disconnection times, which are clearly linked to connections,
>> >> > especially with -C. So I'd rather have the more meaningful figure even
>> >> > at the price of a small change in an undocumented feature.
>> >> 
>> >> +1. The aim of -C is trying to measure connection overhead which
>> >> naturally includes disconnection overhead.
>> > 
>> > I think it is better to measure disconnection delays when -C is specified in
>> > pg 14. This seems not necessary when -C is not specified because pgbench just
>> > reports "initial connection time".
>> 
>> Ok.
>> 
>> > However, what about pg13 or later? Do you think we should also change the
>> > behavior of pg13 or later? If so, should we measure disconnection delay even
>> > when -C is not specified in pg13?
>> 
>> You mean "pg13 or before"?
> 
> Sorry, you are right. I mean "pg13 or before".

I would think we should leave as it is for pg13 and before to not surprise users.
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp



Commits

  1. pgbench: Fix bug in measurement of disconnection delays.

  2. pgbench: Avoid unnecessary measurement of connection delays.

  3. pgbench: Improve time logic.