6.7.5. Fairshare Feature
When using a priority queue, a velocity mismatch between message producers and consumers can result in lower priority messages remaining in the queue indefinitely. To ensure that messages of all priorities are serviced, the fairshare feature can be used to grab a predetermined number of messages for each priority level.
The
x-qpid-fairshare argument of the x-declare: argument can be used to enforce either a common number of messages to be grabbed per-priority-level, or a custom number of messages per-priority-level
The following example creates a queue with 10 priority levels, and will grab 5 messages from each priority in turn:
- C++
Sender sender = session.createSender('my-queue; {create: always, node:{x-declare:{arguments:{qpid.priorities:10, x-qpid-fairshare: 5}}}}')
The following example creates a queue with 10 priority levels, with custom fairshare amounts per-priority-level:
- C++
Sender sender = session.createSender('my-queue; {create: always, node:{x-declare:{arguments:{qpid.priorities:10, x-qpid-fairshare-0: 3, x-qpid-fairshare-1: 5, x-qpid-fairshare-2: 3, x-qpid-fairshare-3: 2, x-qpid-fairshare-4: 4, x-qpid-fairshare-5: 5, x-qpid-fairshare-6: 5, x-qpid-fairshare-7: 3, x-qpid-fairshare-8: 5, x-qpid-fairshare-9: 4, x-qpid-priorities: 10}}}}')
