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From: Tom Lane <tgl@sss.pgh.pa.us>
To: andres@anarazel.de
Cc: Gurjeet Singh <gurjeet@singh.im>
Cc: Peter Eisentraut <peter_e@gmx.net>
Cc: PGSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels
Date: Tue, 10 Jun 2014 11:52:17 -0400
Message-ID: <31348.1402415537@sss.pgh.pa.us> (raw)
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andres@anarazel.de (Andres Freund) writes:
> On 2014-06-10 11:20:28 -0400, Tom Lane wrote:
>> Maybe I'm mistaken, but I thought once the fork_process code has reset our
>> process's setting to zero it's not possible to lower it again (without
>> privileges we'd not have).

> No, doesn't look that way. It's possible to reset it to the value set at
> process start. So unless we introduce double forks for every backend
> start it can be reset by ordinary processes.

That's kind of annoying --- I wonder why they went to the trouble of doing
that?  But anyway, it's probably not worth the cost of double-forking to
prevent it.  I still say though that this is not a reason to make it as
easy as change-a-GUC to break the intended behavior.

Robert's idea of having the start script set an environment variable to
control the OOM adjustment reset seems like it would satisfy my concern.

			regards, tom lane


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