Challenges of Stream Data Processing
Multiple, continuous, rapid, time-varying, ordered streams
Main memory computations
Queries are often continuous
Evaluated continuously as stream data arrives
Answer updated over time
Queries are often complex
Beyond element-at-a-time processing
Beyond stream-at-a-time processing
Beyond relational queries (scientific, data mining, OLAP)
Multi-level/multi-dimensional processing and data mining
Most stream data are at low-level or multi-dimensional in nature