Date: Mon, 24 Feb 2020 16:14:53 -0300
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Thomas Munro <thomas.munro@gmail.com>,
	=?iso-8859-1?Q?R=E9mi?= Zara <remi_zara@mac.com>,
	Michael Paquier <michael@paquier.xyz>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pgsql: Add kqueue(2) support to the WaitEventSet API.
Message-ID: <20200224191453.GA711@alvherre.pgsql>
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On 2020-Feb-24, Tom Lane wrote:

> We could also consider a HINT, along the lines of "Raise the server's
> max_files_per_process and/or \"ulimit -n\" limits."  This again has
> the ambiguity about which server, and it also seems dangerously
> platform-specific.

Maybe talk about "the local server" to distinguish from the other one.

As for the platform dependencies, I see two main options: make the hint
platform-specific (i.e have #ifdef branches per platform) or make it
even more generic, such as "file descriptor limits".

A quick search suggests that current Windows itself doesn't typically
have such problems:
https://stackoverflow.com/questions/31108693/increasing-no-of-file-handles-in-windows-7-64-bit
https://docs.microsoft.com/es-es/archive/blogs/markrussinovich/pushing-the-limits-of-windows-handles

But the C runtime does:
https://docs.microsoft.com/en-us/cpp/c-runtime-library/file-handling?view=vs-2019
I suppose we do use the C runtime.  There's a reference to
_setmaxstdio() being able to raise the limit from the default of 512 to
up to 8192 open files.  We don't currently invoke that.
https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/setmaxstdio?view=vs-2019

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services