process of discarding data when input rates increase beyond system capacity. • Load shedding techniques operate in a dynamic fashion: the system detects an overload situation during runtime and selectively case of known aggregation functions, results can be scaled using approximate query processing techniques, where accuracy is measured in terms of relative error in the computed query answers. 17 ?? streams. (VLDB’06) • N. Tatbul, U. Çetintemel, and S. Zdonik. Staying fit: Efficient load shedding techniques for distributed stream processing. (VLDB’07) • N. R. Katsipoulakis, A. Labrinidis, and P.

upstream backup, operators need to track and log tuple provenance / result lineage. Can such techniques be efficiently implemented? What if more than one nodes fail at the same time? 18 Vasiliki

evenly • Data-parallel streaming languages enable fission by construction • Elastic scaling techniques enable dynamic operator fission by adjusting the number of parallel operator instances according