Continuous Query Language (CQL) is an SQL-like language used for real-time stream processing. Compared with SQL, CQL has introduced the concept of (time-sequencing) window, which allows data to be stored and processed in the memory. The CQL output is the computing results of data streams at specific time. The use of CQL accelerates service development, enables tasks to be easily submitted to the Storm platform for real-time processing, facilitates output of results, and allows tasks to be terminated at the appropriate time.
Nimbus HA ensures continuous service processing such as adding topologies and management even if one Nimbus is faulty, improving cluster availability.