You can use a lambda structure which is , hbase along with some stream-compute tools such as spark streaming. You store data in hbase ,and when there is new data coming ,update both original data and report by stream-compute. When a new report is created ,you can generate it from a full-scan of hbase, after that ,the report can by updated by stream-compute. You can also use a map-reduce job to adjust the stream-compute result periodically.