Show Table of Contents
7.2.4. Query Sender Capacity
When using asynchronous message sending, three sender properties are available to ascertain the state of the asynchronous calls. They are:
- Sender Capacity
- The maximum number of asynchronously sent messages that can be pending acknowledgement at any given time. By default this is
UNLIMITED, but it can be changed to constrain the number of unsettled asynchronous calls. An attempt to make a further asynchronous call when the sender is at capacity will block until another sent message is acknowledged by the broker.- C++
sender.getCapacity()
- Python
sender.capacity
- Sender Unsettled
- The number of asynchronous sends pending acknowledgement from the broker.
- C++
sender.getUnsettled()
- Python
sender.unsettled()
- Sender Available
- The number of additional asynchronous calls that the sender can accept at the moment. This value is available as a property, but can also be computed from
sender.capacity-sender.unsettled.- C++
sender.getAvailable()
- Python
sender.available()

Where did the comment section go?
Red Hat's documentation publication system recently went through an upgrade to enable speedier, more mobile-friendly content. We decided to re-evaluate our commenting platform to ensure that it meets your expectations and serves as an optimal feedback mechanism. During this redesign, we invite your input on providing feedback on Red Hat documentation via the discussion platform.