Hi Marc, Am Mittwoch, den 20.10.2010, 00:54 +0200 schrieb Marc Wilmots: > Hi List, > > I installed Lambda Probe to debug a problem that I'm having with a Liferay > portal (5.1.2): > > Tomcat: 6.0.26 with dbcp > JDK: 1.6.0_18 > DB: Oracle 10.2.0.4 (ojdbc14) > RHEL 5.4 64Bits > > When launching a stress test with JMeter, Lambda Probe indicates that my > connection pool (150 connections (I know..extremely high)) is out of free > connections (150 Busy and Established). However, when I do a netstat, there > are only 20-30 established connections to the database. > > I would rather believe netstat over Probe, however when Lambda Probe > indicates that my pool is out of connections I noticed that the stress test > is going extremely slow and several requests are failing because of a > response time out (60secs). (The Tomcat connection pool (500 threads) gets > filled as well) Try generating thread-dumps when your tomcat is under that load. That way you can see where you might have problems.
> > Why could it be that Probe indicates 150 established connections and netstat > only 20-30? I think Probe differentiates between established (pooled) connections and busy (currently in use) connections. Maybe the established connections are lazy and have no direct connection to the database. Haven't checked it, so they very well be in another state, like abandoned and cut down by a firewall... Your best bet is to look at the thread-dumps. > According to the DBA, the DB is not stressed at all. > > As soon as the stress test stops, the pool recovers itself. Netstat and > Lambda numbers (idle connections) are now exactly the same. dbcp will shrink the pool to the desired "minIdle" settings when no new connections are needed. HTH Felix > > I know it's extremely (if not impossible) to indicate me what the problem > might be. I just would like to know how I should proceed to investigate this > problem, as I'm currently out of ideas. > > > Thanks in advance! --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
