Publish/Subscribe in NoSQL

Present NoSQL databases are passive entities, where users proactively access the databases serving requested issued by users. While NoSQL databases are scalable due to their horizontal scale-out designs, data items stored in potentially very large databases are difficult to retrieve in terms of access delay, programmability and usability. In this paper, we advocate supporting events in NoSQL. By introducing publishers and subscribers to NoSQL, our proposed NoSQL data store is capable of proactively delivering data items that users are interested in. Additionally, our NoSQL database decouples publishers and subscribers such that application developers can emphasize on data manipulation without paying attention to communications for delivering data. We formally discuss the design requirements for streaming in NoSQL, and present a prototype implementation that addresses the design issues. Our implementation is then benchmarked, and the performance results are discussed. We finally outline potential enhancements to our proposal in this paper.