Appreciate your valuable inputs. We are not using web services to EJB through JMeter. We are wondering if thread pool size not affecting the performance could be becuase we are using jboss-4.2.2.GA free/open source version. We are not using commercial version of JBoss for the development. We seeing following errors in the log files when there running throug JMeter for 500 threads and 2 loops: 2008-03-19 01:59:07,926 DEBUG [org.jboss.mq.pm.jdbc2.PersistenceManager] Could not create table with SQL: CREATE CACHED TABLE JMS_MESSAGES ( MESSAGEID INTEGER NOT NULL, DESTINATION VARCHAR(255) NOT NULL, TXID INTEGER, TXOP CHAR(1), MESSAGEBLOB OBJECT, PRIMARY KEY (MESSAGEID, DESTINATION) ) java.sql.SQLException: Table already exists: JMS_MESSAGES in statement [CREATE CACHED TABLE JMS_MESSAGES] at org.hsqldb.jdbc.Util.throwError(Unknown Source) at org.hsqldb.jdbc.jdbcPreparedStatement.executeUpdate(Unknown Source) at org.jboss.resource.adapter.jdbc.CachedPreparedStatement.executeUpdate(CachedPreparedStatement.java:95) at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeUpdate(WrappedPreparedStatement.java:251) at org.jboss.mq.pm.jdbc2.PersistenceManager.createSchema(PersistenceManager.java:273) at org.jboss.mq.pm.jdbc2.PersistenceManager.startService(PersistenceManager.java:1789) at org.jboss.system.ServiceMBeanSupport.jbossInternalStart(ServiceMBeanSupport.java:289) at org.jboss.system.ServiceMBeanSupport.jbossInternalLifecycle(ServiceMBeanSupport.java:245) at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.jboss.mx.interceptor.ReflectedDispatcher.invoke(ReflectedDispatcher.java:155) at org.jboss.mx.server.Invocation.dispatch(Invocation.java:94) at org.jboss.mx.server.Invocation.invoke(Invocation.java:86) at org.jboss.mx.server.AbstractMBeanInvoker.invoke(AbstractMBeanInvoker.java:264) at org.jboss.mx.server.MBeanServerImpl.invoke(MBeanServerImpl.java:659) at org.jboss.system.ServiceController$ServiceProxy.invoke(ServiceController.java:978) at $Proxy0.start(Unknown Source) at org.jboss.system.ServiceController.start(ServiceController.java:417) at org.jboss.system.ServiceController.start(ServiceController.java:435) at org.jboss.system.ServiceController.start(ServiceController.java:435) at org.jboss.system.ServiceController.start(ServiceController.java:435) at org.jboss.system.ServiceController.start(ServiceController.java:435) at org.jboss.system.ServiceController.start(ServiceController.java:435) at sun.reflect.GeneratedMethodAccessor9.invoke(Unknown Source) Any help would be greatly appreciated. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=4137616#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...