Queues

A queue is an application server component that can facilitate parallel processing. Associating a queue with an e-mail listener can speed up the sequential processing of incoming e-mails, especially when they are arriving in high volume.

The E-mail Listeners application processes incoming e-mail messages in a sequential manner. The sequence of processing includes polling the mail server, staging the mail into the database, and launching workflow processing on the staged mail record. In situations where high volumes of e-mail messages must be processed efficiently, this sequential processing can be time-consuming. This means that e-mail messages are not always processed as quickly as possible. Therefore, it can be beneficial to switch the e-mail listener to a parallel processing mode. To perform this switch, you can configure a queue and associate the queue with the listener. The system uses Java™ Messaging Service (JMS) queues, provided by the underlying Java application server.

Once a message is placed in a queue, the message processing component can pick the message up in an asynchronous manner. In the Java application server, the processing components are called message-driven beans (MDBs). You can configure the application server to provide multiple MDBs that process multiple messages in parallel. This increases the speed at which the E-mail Listeners application processes e-mails.

Once you set up the queues, you can modify or create an e-mail listener definition to specify queue-based processing, the queue name, and the queue connection factory name.