From: Tom Lane <tgl@sss.pgh.pa.us>
To: Gurjeet Singh <gurjeet@singh.im>
cc: Andres Freund <andres@anarazel.de>, Peter Eisentraut <peter_e@gmx.net>,
 PGSQL Hackers <pgsql-hackers@postgresql.org>
Subject: Re: /proc/self/oom_adj is deprecated in newer Linux kernels
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Comments: In-reply-to Gurjeet Singh <gurjeet@singh.im>
 message dated "Mon, 23 Jun 2014 12:33:00 -0400"
Date: Mon, 23 Jun 2014 09:49:24 -0700
Message-ID: <17054.1403542164@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Gurjeet Singh <gurjeet@singh.im> writes:
> On Mon, Jun 23, 2014 at 11:52 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> While this is clearly an improvement over what we had before, it's
>> impossible to argue that it's a bug fix, and we are way past the 9.4
>> feature freeze deadline.  In particular, packagers who've already done
>> their 9.4 development work might be blindsided by us slipping this into
>> 9.4 release.  So while I wouldn't have a problem with putting this change
>> into 9.4 from a technical standpoint, it's hard to argue that it'd meet
>> project norms from a development-process standpoint.

> While I'd love to reduce the number of future installations without
> this fix in place, I respect the decision to honor project policy. At
> the same time, this change does not break anything. It introduces new
> environment variables which change the behaviour, but behaves the old
> way in the absence of those variables.

Uh, no, it doesn't.  We removed the dependence on -DLINUX_OOM_SCORE_ADJ.
If a packager is expecting that to still work in 9.4, he's going to be
unpleasantly surprised, because the system will silently fail to do what
he's expecting: it will run all the backend processes at no-OOM-kill
priority, which is likely to be bad.

It is possible to make packages that will work either way, along the lines
of the advice I sent to the Red Hat guys:
https://bugzilla.redhat.com/show_bug.cgi?id=1110969

but I think it's a bit late in the cycle to be telling packagers to do
that for 9.4.

> BTW, does the project publish the feature-freeze deadlines and other
> dates somewhere (apart from on this list).

It's usually in the dev meeting minutes
https://wiki.postgresql.org/wiki/PgCon_2014_Developer_Meeting#9.5_Schedule

			regards, tom lane


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