What is Query Optimizer

Data-stream query processing and mining is an emerging challenge for the database research community. This issue has recently gained the attention from the academic as well as the industrial world. Data streams are continuously flooding data produced by untraditional information sources. They are generated by a growing number of data entities, among all we recall performance measurements in network monitoring and traffic management systems, call details records in telecommunication systems, transactions in retail chains, ATM operations, log records generated by Web servers, sensor network data, RFID- (radio frequency identification) based readings, and so forth.