Progress Sonic ESB Configuration and Management Guide

Chapter 3: ESB Endpoints and Connections
Table 1 maps the destination configurations to destination requirements.
Table 1. Mapping Destination Requirements
QoS
AT_LEAST_ONCE
or
EXACTLY_ONCE
Destination
Type Multiple Services Single Service Instances
Topic ● Concurrent durable subscription =
true
● Shared subscriptions = true
● Number of listeners = any number
● Durable subscription name must be
non-null
When to Use Topics, When to Use Queues
● Concurrent durable subscription =
false
● Shared subscriptions = false
● Number of listeners = 1
● Durable subscription name must be
non-null
Queue ● No additional configuration required ● No additional configuration required
BEST_EFFORT Topic ● Concurrent durable subscription =
true
● Shared subscriptions = true
● Number of listeners = any number
● Durable subscription name must be
null
● Concurrent durable subscription =
false
● Shared subscriptions = false
● Number of listeners = 1
● Durable subscription name must be
null
Queue ● No additional configuration required ● No additional configuration required
When deciding whether to use queues or topics in your applications, consider that the
underlying Progress SonicMQ layer provides some queue-like behavior for topics. The
shared subscription feature enables you to have persistent, load balanced topic subscribers
in your applications, while still allowing other subscribers on the topics.
If you use topics, other services can receive and process messages without interfering with
message flow through a process. Using this implementation, you can monitor business
activity with a monitoring service subscribed to one topic, while message flow continues
uninterrupted through a service subscribed to a different topic. This implementation is
also useful in debugging and testing your applications and processes.
See the Progress SonicMQ Application Programming Guide for a detailed discussion of
the features and benefits of using queues or topics in your applications. If you use topics,
there are other considerations in defining the endpoints that relate to the number of service
instances and the QoS. The following sections describe implementing concurrent durable
subscriptions and shared subscriptions on topics in Sonic ESB.
99 Progress Sonic ESB Configuration and Management Guide 8.5