43.5. Avoiding Anti-Patterns
- Re-use connections, sessions, consumers, and producers. Probably the most common messaging anti-pattern observed, is users who create a new connection, session, or producer for every message sent, or every message consumed. This is a poor use of resources. Always reuse these objects as they take time to create and may involve several network round trips.
Note
Some popular libraries such as the Spring JMS Template are known to use these anti-patterns. If using Spring JMS Template, it is possibly a cause for poor performance and not HornetQ. The Spring JMS Template can only safely be used in an app server which caches JMS sessions (for example. using JCA), and only then for sending messages. It cannot be safely be used for synchronously consuming messages, even in an app server. - Avoid fat messages. Verbose formats such as XML result in increased server transmission load and performance will suffer as result. Avoid XML in message bodies if possible.
- Do not create temporary queues for each request. This common anti-pattern involves the temporary queue request-response pattern. With the temporary queue request-response pattern a message is sent to a target and a reply-to header is set with the address of a local temporary queue. When the recipient receives the message they process it then send back a response to the address specified in the reply-to. A common mistake made with this pattern is to create a new temporary queue on each message sent. This will drastically reduce performance. Instead the temporary queue should be re-used for many requests.
- Do not use Message-Driven Beans unnecessarily. MDB usage greatly increases the code path for each message received compared to a straightforward message consumer, as a lot of extra application server code is executed. Before using MDBs, investigate the use of a normal message consumer to complete the task.
