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From: Tom Lane <[email protected]>
To: Andres Freund <[email protected]>
Cc: Tomas Vondra <[email protected]>
Cc: Jelte Fennema-Nio <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Subject: Re: Bump soft open file limit (RLIMIT_NOFILE) to hard limit on startup
Date: Tue, 11 Feb 2025 16:18:37 -0500
Message-ID: <[email protected]> (raw)
In-Reply-To: <7u7dbn6s2i6bf3hjzkbqaexj2bpoblqxwbkffbetl4rjv6dcom@s2uickjc5z53>
References: <CAGECzQQh6VSy3KG4pN1d=h9J=D1rStFCMR+t7yh_Kwj-g87aLQ@mail.gmail.com>
	<[email protected]>
	<[email protected]>
	<7u7dbn6s2i6bf3hjzkbqaexj2bpoblqxwbkffbetl4rjv6dcom@s2uickjc5z53>

Andres Freund <[email protected]> writes:
> My suggestion would be to redefine max_files_per_process as the number of
> files we try to be able to open in backends. I.e. set_max_safe_fds() would
> first count the number of already open fds (since those will largely be
> inherited by child processes) and then check if we can open up to
> max_files_per_process files in addition. Adjusting the RLIMIT_NOFILE if
> necessary.

Seems plausible.  IIRC we also want 10 or so FDs available as "slop"
for code that doesn't go through fd.c.

> And when using something like io_uring for AIO, it'd allow to
> max_files_per_process in addition to the files requires for the io_uring
> instances.

Not following?  Surely we'd not be configuring that so early in
postmaster start?

			regards, tom lane

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