Re: Regression tests fail on OpenBSD due to low semmns value

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Andres Freund <andres(at)anarazel(dot)de>
Cc: Peter Eisentraut <peter(at)eisentraut(dot)org>, Andrew Dunstan <andrew(at)dunslane(dot)net>, Alexander Lakhin <exclusion(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Regression tests fail on OpenBSD due to low semmns value
Date: 2024-12-18 17:49:46
Message-ID: 2787971.1734544186@sss.pgh.pa.us
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Andres Freund <andres(at)anarazel(dot)de> writes:
> On 2024-12-18 12:00:48 -0500, Tom Lane wrote:
>> NetBSD does, but they consume an FD per sema, which is actually worse
>> because the default max-open-files-per-process is none too large either.

> Doesn't seem that bad on netbsd 10. Via Bilal's netbsd CI patch, I get:
> # sysctl proc.curproc.rlimit.descriptors
> proc.curproc.rlimit.descriptors.soft = 1024
> proc.curproc.rlimit.descriptors.hard = 3404

Hmm, on mamba's host I see

proc.curproc.rlimit.descriptors.soft = 128
proc.curproc.rlimit.descriptors.hard = 1772

I had actually tried building with unnamed semas there a couple days
ago, and found that the postmaster failed to start. 21fb39cb0 should
have alleviated that (didn't test it yet). But we're still in a
very limited-resource regime. That with the old performance tests
you dredged up makes me not want to switch sema types.

>> Yeah, I would not expend a lot of effort on this. But two one-line
>> changes doesn't seem unreasonable.

> Agreed for stuff like SEMAS_PER_SET. I just don't think it's a good idea to
> invest in lowering our default semaphore requirements by lowering various
> default process limits or such.

Fair, seems like we're on the same page.

regards, tom lane

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