Explore the evolution and future of stream processing in the cloud era through this CMU Database Group seminar. Delve into the values, costs, and challenges of stateful stream processing, tracing its history from single-node systems to big data and cloud environments. Examine innovative approaches to state management, including tiered storage and rethinking design principles. Investigate critical aspects such as failure recovery and elastic scaling. Gain insights into challenging problems facing the field and potential solutions. Learn how RisingWave Labs is addressing these issues and reimagining stream processing for modern cloud architectures.