On Mon, May 29, 2006 at 07:35:14AM -0700, Cstdenis wrote: > > To be honest, you're pushing things expecting a machine with only 1G to > > serve 300 active connections. How large is the database itself? > > The database is 3.7G on disk. There is about 1G of actual data in it -- the > rest is dead tuples and indices. (I vacuum regularly, but a vacuum full > causes too much downtime to do unless I have to) It sounds like you're not vacuuming anywhere near regularly enough if you have that much dead space. You should at least reindex. > > > I know hyperthreading is considered something that can slow down a > server but with my very high concurancy (averages about 400-500 concurant > users during peak hours) I am hoping the extra virtual CPUs wil help. Anyone > have experance that says diferent at high concurancy? > > > > Best bet is to try it and see. Generally, people find HT hurts, but I > > recently saw it double the performance of pgbench on a windows XP > > machine, so it's possible that windows is just more clever about how to > > use it than linux is. > > Anyone know if those who have found it hurts are low concurancy complex cpu > intensive queries or high concurancy simple queries or both? I can > understand it hurting in the former, but not the later. I'll have to give it > a try I guess. It should at least help my very high load averages. The issue is that HT doesn't give you anything close to having 2 CPUs, so for all but the most trivial and limited cases it's not going to be a win. Incidentally, the only good results I've seen with HT are on windows. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
