On Sat, Apr 7, 2012 at 11:05 AM, Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote: > On Sat, Apr 7, 2012 at 11:06 AM, Josh Kupershmidt <schmiddy@xxxxxxxxx> wrote: >> The wiki says nice_backend_super() might be able to "renice any >> backend pid and set any priority, but is usable only by the [database] >> superuser", hinting that it would be feasible to lower a backend's >> priority value (i.e. increase the scheduling priority). Unfortunately >> this is not possible on at least OS X and Linux, where one must be >> root to lower priority values. I haven't checked whether this module >> works on Windows, would appreciate if someone could give it a shot >> there. > > I thought you were limited to only settings above 0 and your own > processes in linux. For non-root users, you may always only *increase* the priority values of your processes, and the default priority value is 0. So yes as non-root, you're effectively limited to positive and increasing values for setpriority(), and of course you may only alter process priorities running under the same user. I think that's what I was saying above, though maybe I wasn't so clear. For example, if you try to lower your own backend's priority with this function, you'll get a warning like this: test=# SELECT set_backend_priority(pg_backend_pid(), -1); WARNING: Not possible to lower a process's priority (currently 0) set_backend_priority ---------------------- f (1 row) Josh -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
