Bruce Momjian wrote: > Stefan Kaltenbrunner wrote: >> Bruce Momjian wrote: >>> OK, based on reports I have seen, generally stats_query_string adds 50% >>> to the total runtime of a "SELECT 1" query, and the patch reduces the >>> overhead to 25%. >> that is actually not true for both of the platforms(a slow OpenBSD >> 3.9/x86 and a very fast Linux/x86_64) I tested on. Both of them show >> virtually no improvement with the patch and even worst it causes >> considerable (negative) variance on at least the Linux box. > > I see the results I suggested on OpenBSD that you reported. > >> OpenBSD 3.9-current/x86: >> >> without stats: >> 0m6.79s real 0m1.56s user 0m1.12s system >> >> -HEAD + stats: >> 0m10.44s real 0m2.26s user 0m1.22s system >> >> -HEAD + stats + patch: >> 0m10.68s real 0m2.16s user 0m1.36s system
yep those are very stable even over a large number of runs > > and I got similar results reported from a Debian: > > Linux 2.6.16 on a single processor HT 2.8Ghz Pentium compiled > with gcc 4.0.4. > > > > real 0m3.306s > > > real 0m4.905s > > > real 0m4.448s > > I am unclear on the cuase for the widely varying results you saw in > Debian. > I can reproduce the widely varying results on a number of x86 and x86_64 based Linux boxes here (Debian,Fedora and CentOS) though I cannot reproduce it on a Fedora core 5/ppc box. All the x86 boxes are SMP - while the ppc one is not - that might have some influence on the results. Stefan ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
