In the Continuuity AppFabric, a flow processes events in real time with exactly-once guarantee, passing interstitial data downstream via queues. All operations involved in processing of a data object, from dequeuing through data operations in the course of processing to emission of new data objects, are performed with ACID properties: atomically, consistently, isolated and durably.

Queues in a flow are demanding: They must support roll-back of queue operations for transactions, reading of a queue by multiple, partitioned and distributed consumers, retention of data objects after dequeue, and deletion after all consumers have successfully processed, and at the same time they must be durably persistent.

We have developed the Continuity Data Fabric as a unified, transactional queuing and columnar table system that supports all of the above requirements. This talk will discuss the implementation on top of HBase, evaluate performance, scalability and reliability, and share experiences, best practices, and lessons learned.