Re: configurability of OOM killer

Tom Lane wrote:
> Florian Weimer <fweimer(at)bfk(dot)de> writes:
>> * Alvaro Herrera:
>>> I am wondering if we can set the system up so that it skips postmaster,
>
>> How much does that help? Postmaster &c still need to be shut down
>> when a regular backend dies due to SIGKILL.
>
> The $64 problem is that if the parent postmaster process is victimized
> by the OOM killer, you won't get an automatic restart. In most people's
> eyes that is considerably worse than the momentary DOS imposed by a kill
> of a child backend. And what we now find, which is truly staggeringly
> stupid on the kernel's part, is that it *preferentially* kills the
> parent instead of whatever child might actually be eating the memory.

Maybe we should just react equally brute-force, and just disable the
OOM-Killer for the postmaster if we're running on linux. It seems that
something like "echo -17 > /proc/<pid>/oom_adj" should do the trick.

And maybe add a note to the docs telling people to disable memory
overcommit on dedicated database servers if that isn't already there...

regards, Florian Pflug