Martijn van Oosterhout <kleptog@svana.org> writes:
> What I don't understand is that with true strict overcommit, the kernel
> should never need to kill your process since there is always in
> principle enough room.
Indeed.  Are you *sure* you have overcommit turned off?  That should
disable the OOM killer altogether.  You should probably go read the
kernel documentation rather than assume Postgres' documentation knows
what it's talking about ;-)
            regards, tom lane