Re: /proc/self/oom_adj is deprecated in newer Linux kernels

Gurjeet Singh <gurjeet(at)singh(dot)im> writes:
> On Mon, Jun 23, 2014 at 11:52 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)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