Alvaro Herrera <alvherre(at)commandprompt(dot)com> writes:
> I notice that most of the difference is system time ... I imagine we do
> a lot of syscalls to guess the timezone.
Yeah, it seems to be mostly the cost of searching the timezone directory
tree and reading all those small files. I was led to notice this
because Red Hat's latest devel kernels seem to have a bit of a
performance regression in this area:
https://bugzilla.redhat.com/show_bug.cgi?id=548403
Obviously there's something there for the kernel guys to fix, but
even with a non-borked kernel it's an expensive thing to do.
regards, tom lane