Sliding-Window Aggregation Algorithms: Tutorial

Stream processing is important for analyzing continuous streams of data in real time. Sliding-window aggregation is both needed for many streaming applications and surprisingly hard to do efficiently. Picking the wrong aggregation algorithm causes poor performance, and knowledge of the right algorithms and when to use them is scarce. This paper was written to accompany a tutorial, but can be read as a stand-alone survey that aims to better educate the community about fast sliding-window aggregation algorithms for a variety of common aggregation operations and window types.