under normal conditions, a single webserver shouldn't have several thousand DB connections. that seems a bit odd to me.
peter lin On 12/15/05, Martin Gainty <[EMAIL PROTECTED]> wrote: > > Marc- > what types of Coyote Point Equalizers are you using? > What does the Doc say about configuring the CPE for 30-40 consecutive > users? > Martin- > ----- Original Message ----- > From: "Marc Richards" <[EMAIL PROTECTED]> > To: "Tomcat Users List" <users@tomcat.apache.org> > Sent: Thursday, December 15, 2005 7:57 PM > Subject: Performance degradation under load > > > >I have a performance issue that I'm having trouble > > with - perhaps somebody has seen this sort of thing > > before and can help me out. > > > > Problem: > > Under no load my page responses average about 1.2 > > seconds (according to jmeter tests), which is pretty > > good considering the heavy jdbc useage of my > > applications. However, once I begin to ramp up the > > load to 30 or 40 consecutive users the performance > > quickly degrades down to about 4 seconds average > > response time. While this takes place, the machines > > are only showing about 5% cpu utilization and have > > 3.5gb of memory freely available. Network resources > > also appear to be free. So I definitely don't have a > > hardware issue, especially considering that there are > > two balanced machines and neither are showing more > > than 5% busy. I seem to have a bottle neck somewhere > > in the system, but am unsure how to track it down. > > > > Setup background: > > This is a new setup that's not in production yet. I'm > > running Apache 2.05x and Tomcat 5.5x using mod_jk. > > Apache and Tomcat reside together on both machines > > (Win 2003), so there should be virtually no latency > > between them. The machines are balanced on the front > > end by Coyote Point Equalizers. > > > > Tomcat is handling connection pooling to our iSeries > > database server (db2, jdbc), but I'm not sure it's > > working correctly because when I do netstat I see > > several thousand db connections sitting at TIME_WAIT > > (presumably abandoned and waiting to be cleaned up by > > the pool manager). This could be one of my problems, > > but I don't think it's the whole problem and I don't > > know how to verify. The call to the pool manager is > > actually coming from the Spring Framework, which > > possibly has a bug in it, but I suspect instead that > > Tomcat is not returning the connections to the pool > > (unless I'm interpreting the existance of so many > > connections entirely wrong to begin with). > > I'm also using Tomcat to persist my sessions > > occasionally (every 2 minutes) to the same iSeries. > > > > I see several possible bottle neck points; the http > > forward from the load balancer to the server machine > > (very unlikely), the tcp communication between Tomcat > > and Apache (maybe), the jdbc connections to the > > iSeries (this is my top suspect at the moment) or some > > sort of db collusion occuring on the sessions > > persistance table. > > > > The big question: Anybody know a slick way to find > > out what it is? > > > > Thanks, > > > > -marc > > > > > > > > > > > > __________________________________________________ > > Do You Yahoo!? > > Tired of spam? Yahoo! Mail has the best spam protection around > > http://mail.yahoo.com > > > > --------------------------------------------------------------------- > > To unsubscribe, e-mail: [EMAIL PROTECTED] > > For additional commands, e-mail: [EMAIL PROTECTED] > > > > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: [EMAIL PROTECTED] > For additional commands, e-mail: [EMAIL PROTECTED] > >
