"Marc G. Fournier" <scrappy@postgresql.org> writes:
>> If we force people to give a --without-spinlocks config option to build
>> that way, then `pg_config --configure' will reveal the dirty deed ...
> That's not quite what I meant :) Right now, if I understood what Bruce
> was saying, if someone doesn't have spinlocks, it switches to using SysV
> Messenging, correct? In the current system, is there anything that one
> can do on a running, live system, to detect that you aren't using
> spinlocks?
It'll be fairly obvious if you use "ipcs -s" and count up the number of
semaphores created by the postmaster. Ordinarily we will grab
approximately max_connections semas, but without spinlocks it will
be somewhere north of max_connections + 2 * shared_buffers ...
regards, tom lane