Display JMS connection pool contents

Recently I have been having problem with an application seeming to use up all the available connections in an MQ connection pool. To enable me to show what was going on to the developers I needed to create a jython script to show the pool contents and how long the connections had been in use for.

The connections in the pool did not appear to be getting freed up even when the purge timer was reached, so we set up the stuck timer under connection pool ==> advance settings.

This at least provided warnings in the logs that there were stuck threads - "A stuck connection is an active connection that is not responding or returning to the connection pool."

This provided some messages in the log to prove what we expected but as tends to be the case this wasn't sufficient. So I set up the following script to run at regular intervals:

ps = AdminControl.queryNames ('WebSphere:type=J2CConnectionFactory,process=server1,*').splitlines()
for p in ps:
print p
pc=AdminControl.invoke( p , "showPoolContents" )
print pc
This gave all sorts of useful information including details on each connection:

MCWrapper id 7d597d59 Managed connection com.ibm.ejs.jms.JMSManagedQueueConnection@6b376b37
managed connection factory = com.ibm.ejs.jms.WSJMSManagedQueueConnectionFactory@50f350f3
physical connection = com.ibm.mq.jms.MQXAQueueConnection@6beb6beb
credential = null
open connection handles = [com.ibm.ejs.jms.JMSQueueConnectionHandle@48324832] State:STATE_TRAN_WRAPPER_INUSE Start time inuse Thu Jun 16 18:21:24 BST 2011 Time inuse 53119 (seconds)

The proof I was after was the start time - this tended to be when the app was first run and would just hang around.

Even running the following to purge the pool did not help:

AdminControl.invoke( p , "purgePoolContents" )

The showpoolcontents would show the same information with the following line added:

Connection marked to be destroyed. Waiting for transaction end and connection close.

With this information to hand the developers finally agreed to check out there code!




n.b. If you need to view a database connection pool instead of a JMS pool, change the type in the querynames command to type=DataSource,*