We are performing load testing using jmeter. We are sending thousands of JMS to a queue. There are 3 async services that are involved. If we increase the maxthreads for our esb services from 10 to 20 we experience serious processing delays. If we wait it out it usually self corrects in minutes/hours. This only happens with jms-jca-provider The jms pool is set to 400: <property name="org.jboss.soa.