Re: pgbench logging broken by time logic changes

From: Fabien COELHO <coelho(at)cri(dot)ensmp(dot)fr>
To: Thomas Munro <thomas(dot)munro(at)gmail(dot)com>
Cc: Gregory Smith <gregsmithpgsql(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, david(dot)christensen(at)crunchydata(dot)com
Subject: Re: pgbench logging broken by time logic changes
Date: 2021-06-17 07:24:37
Message-ID: alpine.DEB.2.22.394.2106170917240.2693553@pseudo
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers


Hello Thomas,

>> Before I could get to startup timing I noticed the pgbench logging
>> output was broken via commit 547f04e7 "Improve time logic":
>> https://www.postgresql.org/message-id/E1lJqpF-00064e-C6%40gemulon.postgresql.org
>
> It does suck that we broke the logging and that it took 3 months for
> anyone to notice and report it to the list.

Indeed. Well, it also demonstrates that beta are useful.

> Seems like it should be straightforward to fix, though, with fixes
> already proposed (though I haven't studied them yet, will do).

I think that fixing logging is simple enough, thus a revert is not
necessary.

>> I have a lot of community oriented work backed up behind this right
>> now, so I'm gonna be really honest. This time rework commit in its
>> current form makes me uncomfortable at this point in the release
>> schedule. The commit has already fought through two rounds of platform
>> specific bug fixes. But since the buildfarm doesn't test the logging
>> feature, that whole process is suspect.
>
> It's true that this work produced a few rounds of small portability
> follow-ups: c427de42 (work around strange hacks elsewhere in the tree
> for AIX), 68b34b23 (missing calling convention specifier on Windows),
> and de91c3b9 (adjust pthread missing-function code for threadless
> builds). These were problems that didn't show up on developer or CI
> systems (including threadless and Windows), and IMHO are typical sorts
> of problems you expect to have to work through when stuff hits the
> build farm, especially when using new system interfaces. So I don't
> think any of that, on its own, supports reverting anything here.

Yep, the buildfarm is here to catch portability issues, and it does its
job:-) There is no doubt that logging is has been broken because of lack
of tests in this area, shame on us. I think it is easy to fix.

> [...] For that reason, I'm not super attached to that new pg_time_usec_t
> stuff at all, and wouldn't be sad if we reverted that piece.

Well, I was sooo happy to get rid of INSTR_TIME ugly and inefficient
macros in pgbench… so anything looks better to me.

Note that Michaël is having a look at fixing pgbench logging issues.

--
Fabien.

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Amit Langote 2021-06-17 07:27:56 Re: Skip partition tuple routing with constant partition key
Previous Message Zhihong Yu 2021-06-17 07:23:09 Re: Skip partition tuple routing with constant partition key