Cassandra can be used for queuing in situations where: 1) Messages have different delivery importance and most need to reach consumers at least once. 2) The volume of messages is too high for a single node queue to handle. 3) Latency can be high since queues require polling rather than push delivery. Cassandra allows specifying consistency levels to indicate delivery requirements and shards queues across nodes for high throughput. However, it only provides optimistic locking and polling is needed rather than push delivery.

1. Queuing with Cassandra David Strauss [email_address] @davidstrauss

3. Integrate legacy and new systems

5. Of systems using the queue

6. Possible queue guarantees Deliver exactly once Deliver at least once Deliver no more than once + =

12. No persistence between restarts

15. Application-integrated sharding doesn't count

20. Provides message ordering

24. Give messages unique identity and use locking managed by consumers

25. Use a locking framework like Zookeeper

26. Audit periodically for the effects of duplication and correct

27. Maybe don't use Cassandra...

30. Too much message volume to handle throughput on a single node

31. Willingness to poll and have high latency