I wrote:
> IIRC, newer BSDen use a kernel call for this, so you should be able to
> measure it on your own machine. Just tweak ps_status.c to force it to
> select PS_USE_NONE instead of PS_USE_SETPROCTITLE to generate a
> comparison case. I'll try it on my old HPUX box too.
On HPUX, I get a median time of 5.59 sec for CVS HEAD vs 5.36 sec with
ps_status diked out, for the test case of 10000 "SELECT 1;" as separate
transactions, assert-disabled build. So, almost 10% overhead. Given
that the transactions can't get any more trivial than this, that's about
a worst-case number. Not sure if it's worth worrying about or not.
However Kris Kennaway's report a couple weeks ago suggested things might
be worse on BSD.
regards, tom lane