StreamApprox: Approximate Stream Analytics in Apache Flink

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Approximate computing aims for efficient execution of workflows where an approximate output is sufficient instead of the exact output. The idea behind approximate computing is to compute over a representative sample instead of the entire input dataset. Thus, approximate computing — based on the chosen sample size — can make a systematic trade-off between the output accuracy and computation efficiency. Unfortunately, state-of-the-art systems for approximate computing, such as BlinkDB, ApproxHadoop, primarily target batch analytics, where the input data remains unchanged during the course of sampling. Thus, they are not well-suited for stream analytics. In this talk, we will present the design of StreamApprox, a Flink-based stream analytics system for approximate computing. StreamApprox implements an online stratified reservoir sampling algorithm in Apache Flink to produce approximate output with rigorous error bounds.