Reinventing Backend Subsetting at Google

Abstract

Backend subsetting is useful for reducing costs and may even be necessary for operating within the system limits. For more than a decade, Google used deterministic subsetting as its default backend subsetting algorithm, but although this algorithm balances the number of connections per backend task, deterministic subsetting has a high level of connection churn. Our goal at Google was to design an algorithm with reduced connection churn that could replace deterministic subsetting as the default backend subsetting algorithm.