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Subject: Re: pgsql: Add kqueue(2) support to the WaitEventSet API.
From: =?utf-8?Q?R=C3=A9mi_Zara?= <remi_zara@mac.com>
In-Reply-To: 
 <CA+hUKG+yGQDPdwcH5euDb_pE7OcnbrvGDLoOi2JMaCwj4G+ttg@mail.gmail.com>
Date: Thu, 20 Feb 2020 19:03:59 +0100
Cc: Michael Paquier <michael@paquier.xyz>,
 Thomas Munro <tmunro@postgresql.org>,
 pgsql-committers <pgsql-committers@lists.postgresql.org>
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Message-Id: <08364CCB-07F5-423E-8CE0-ABF0195C4CA2@mac.com>
References: <E1izCmM-0005pV-Co@gemulon.postgresql.org>
 <20200220072435.GM2288@paquier.xyz>
 <CA+hUKG+yGQDPdwcH5euDb_pE7OcnbrvGDLoOi2JMaCwj4G+ttg@mail.gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Precedence: bulk


> Le 20 f=C3=A9vr. 2020 =C3=A0 12:15, Thomas Munro =
<thomas.munro@gmail.com> a =C3=A9crit :
>=20
> On Thu, Feb 20, 2020 at 8:24 PM Michael Paquier <michael@paquier.xyz> =
wrote:
>> On Wed, Feb 05, 2020 at 04:59:10AM +0000, Thomas Munro wrote:
>>> Add kqueue(2) support to the WaitEventSet API.
>>>=20
>>> Use kevent(2) to wait for events on the BSD family of operating
>>> systems and macOS.  This is similar to the epoll(2) support added
>>> for Linux by commit 98a64d0bd.
>>=20
>> Worth noting this issue with the test suite of postgres_fdw for
>> buildfarm animal coypu, running on NetBSD:
>> =
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=3Dcoypu&dt=3D2020-=
02-19%2023%3A01%3A01
>> +ERROR:  kqueue failed: Too many open files
>=20
> Hmm.  So coypu just came back after 48 days, and the new kqueue() code
> fails for process 19829 after successfully running 265 log lines'
> worth of  postgres_fdw tests, because it's run out of file
> descriptors.  I can see that WaitLatchOrSocket() actually could leak
> an epoll/kqueue socket if WaitEventSetWait() raises an error, which is
> interesting, but apparently not the explanation here because we don't
> see a preceding error report.  Another theory would be that this
> machine has a low max_safe_fds, and NUM_RESERVED_FDS is only just
> enough to handle the various sockets that postgres_fdw.sql creates and
> at some point kqueue()'s demand for just one more pushed it over the
> edge.  =46rom the error text and a look at the man page for errno, =
this
> error is EMFILE (per process limit, which could be as low as 64)
> rather then ENFILE (system limit).
>=20
> Remi, any chance you could run gmake installcheck under
> contrib/postgres_fdw on that host, to see if this is repeatable?  Can
> you tell us about the relevant limits?  Maybe ulimit -n (for the user
> that runs the build farm), and also sysctl -a | grep descriptors,
> sysctl -a | grep maxfiles?


Hi,

Unfortunalty, coypu went offline again. I will run tests as soon as I =
can bring it back up.

R=C3=A9mi=