Tuning messaging performance with service integration technologies

To help optimize performance, we can set tuning properties that control the performance of message-driven beans and other messaging applications deployed to use service integration technologies. To optimize the performance of messaging with service integration technologies, we can use the admin console to set various parameters as described in the steps below. We can also set these parameters by using the wsadmin tool.

 

• View the Available Message Count on a destination.

  View the Available Message Count on a destination enables you to determine whether the message consumers are able to cope with the current workload. If the available message count on a given destination is too high, or is increasing over time, consider some of the tuning recommendations in this topic.

  1. Enable AvailableMessageCount statistics for a queue. If you restart the admin server, enable AvailableMessageCount statistics again because such runtime settings are not preserved when the server is restarted.

     1. In the navigation pane, click Monitoring and Tuning > Performance Monitoring Infrastructure (PMI) .

     2. In the content pane, click server_name.

     3. Click the Runtime tab.

     4. In the Currently monitored statistic set, click Custom.

     5. On the Custom monitoring level panel, click SIB Service > SIB Messaging Engines > engine_name > Destinations > Queues > queue_name .

     6. Select the AvailableMessageCount option.

     7. Click Enable at the top of the panel.

  2. View the available message count for a queue.

     1. In the navigation pane, click Monitoring and Tuning > Performance Viewer > Current activity .

     2. In the content pane, click server_name.

     3. Click Performance Modules > SIB Service > SIB Messaging Engines > engine_name > Destinations > Queues > queue_name .

     4. Click View Module(s) at the top of the Resource Selection panel, located on the left side. This displays the AvailableMessageCount data in the Data Monitoring panel, located on the right side.

        Use the Data Monitoring panel to manage the collection of monitoring data; for example, we can use the buttons to start or stop logging, or to change the data displayed as either a table or graph.

• Monitor MDB Thread Pool Size for the Default Message Provider.

  We might experience a performance bottleneck if there are insufficient threads available for the message-driven beans. There is a trade-off between providing sufficient threads to maximize the throughput of messages and configuring too many threads, which can lead to CPU starvation of the threads in the appserver. If you notice that the throughput for express nonpersistent, reliable nonpersistent, or reliable persistent messaging has fallen as a result of increasing the size of the default thread pool, then decrease the size of the thread pool and reassess the message throughput.

  1. View or change the number of threads in the default thread pool for an appserver. By default, message-driven beans use the default thread pool.

     1. Click Servers > Server Types > WebSphere application servers > server_name > [Additional Properties] Thread Pools > Default. By default the Minimum size value is set to 5 and the Maximum size value is set to 20. The best performance is obtained by setting the Maximum size value to the expected maximum concurrency for all message-driven beans. For high throughput using a single message bean, 41 was found to be the optimal Maximum size value.

     2. Change the Maximum size value, then click OK.

  2.  
     Create your own thread pool. The default thread pool is also used by other WAS components, so we might want to define a separate thread pool for the message-driven beans. This reduces thread contention for the default thread pool.

     1. Click Servers > Server Types > WebSphere application servers > server_name > [Additional Properties] Thread Pools .

     2. Create a new thread pool.

     3. Create sufficient threads to support the maximum amount of concurrent work for the message-driven beans.

     4. Change the SIB JMS Resource Adapter to use the new thread pool:

        1. Click Resources > Resource Adapters > Resource adapters .

        2. If we cannot see any SIB JMS Resource Adapter instances in the list, expand Preferences and enable Show built-in resources.

        3. Select the SIB JMS Resource Adapter with the appropriate scope depending upon the scope of the connection factories.

        4. Add the name of the new thread pool in the Thread pool alias box.

        5. Click Apply .

  3. Save the changes to the master configuration.

• Tune MDB performance with the default messaging provider.

  1. Click Resources > JMS > Activation specifications > activation_specification_name .

  2. Set the maximum batch size for this activation specification.

     Delivering batches of messages to each MDB endpoint can improve performance, particularly when used with Acknowledge mode set to Duplicates-ok auto-acknowledge. However, if message ordering must be retained across failed deliveries, set this parameter to 1.

  3. Set the maximum number of concurrent endpoints for this activation specification.

     The maximum concurrent endpoints parameter controls the amount of concurrent work that can be processed by a message bean. The parameter is used with message-driven beans. Increasing the number of concurrent endpoints can improve performance but can increase the number of threads in use at one time. To benefit from a change in this parameter, there should be sufficient threads available in the MDB thread pool to support the concurrent work. However, if message ordering must be retained across failed deliveries, set this parameter to 1.

  4. Save the changes to the master configuration.
  For additional information about tuning the throttling of message-driven beans, including controlling the maximum number of instances of each message bean and the message batch size for serial delivery, see Configure MDB throttling for the default messaging provider.

• Ensure that appservers hosting one or more messaging engines are provided with an appropriate amount of memory for the message throughput you require. We can tune the initial and maximum Java™ Virtual Machine (JVM) heap sizes when adding a server to a messaging bus, that is when creating a messaging engine. You have the option to do this in any of the following cases:

  • When adding a single server to a bus

  • When adding a cluster to a bus

  • When adding a new server to an existing cluster that is itself a bus member

  For an appserver that is a bus member of at least one bus, or a member of a cluster that is a bus member of at least one bus, the recommended initial and maximum heap sizes are 768MB.

  When we are adding a cluster to a bus, we are recommended to increase the initial and maximum JVM heap sizes for every server in the cluster to 768MB.

  • Increasing the initial heap size improves the performance for small average message sizes

  • Increasing the maximum heap size improves the performance for higher average message sizes

• Reduce the occurrence of OutOfMemoryError exceptions

  If the cumulative size of the set of messages being processed within a transaction by the service integration bus is large enough to exhaust the JVM heap, OutOfMemoryError exceptions occur. Consider one of the following options for reducing the occurrence of OutOfMemoryError exceptions when processing a large set of messages within a transaction.

  • Increase the JVM heap sizes for the appserver.

  • Reduce the cumulative size of the set of messages being processed within the transaction.

• Change the maximum connections in a connection factory for the default messaging provider.

  The maximum connections parameter limits the number of local connections. The default is 10. This parameter should be set to a number equal to or greater than the number of threads (enterprise beans) concurrently sending messages.

  1. Click Resources > JMS > Topic connection factories > factory_name > [Additional Properties] Connection pool properties .

  2. Enter the required value in the Maximum connections field.

  3. Click Apply.

  4. Save the changes to the master configuration.

• Tune reliability levels for messages. The reliability level chosen for the messages has a significant impact on performance. In order of decreasing performance (fastest first), the reliability levels are:

  Best effort nonpersistent

  Express nonpersistent

  Reliable nonpersistent

  Reliable persistent

  Assured persistent

  For MDB point-to-point messaging, best effort nonpersistent throughput is more than six times greater than assured persistent. For more information about reliability levels, see Message reliability levels - JMS delivery mode and service integration quality of service.

   

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Last updated Nov 10, 2010 8:23:07 PM CST