>> Then, how about semaphores? When I just do configure, PostgreSQL >> seems to use SysV semaphores. But POSIX semaphore implementation is >> prepared in src/backend/port/posix_sema.c. Why isn't it used by >> default? Does it have any problem? >> > > Either way, Essentially, no one is running out of shared memory due > to semaphores. > In this case, semaphore usage is unrelated to shared memory > shortages.
Yes, of course, shared memory is not related to semaphores. > Also, on many platforms the posix_sema's code is used. Really? When I run 'configure' without any parameter on Red Hat Enterprise Linux 4.0 (kernel 2.6.x), PostgreSQL uses SysV semaphores. I confirmed that by seeing the result of 'ipcs -u'. What platforms is POSIX sema used by PostgreSQL by default? ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq