Poison Message

Sometimes, a badly-formatted message arrives on a destination. In this context, badly-formatted means the receiving application cannot process the message correctly. Such message can cause the receiving application to fail and to back out this badly-formatted message. The message can then be repeatedly delivered to the input queue and repeatedly backed out by the application. These messages are known as Poison Messages.

Shared Subscriptions

A shared non-durable subscription is used by a client which enables to share the work of receiving messages from a durable subscription amongst multiple consumers. A shared durable subscription can therefore have more than one consumer. Each message from the subscription will be delivered to only one of the consumers on that subscription.