When a frequently-accessed cache item expires, multiple requests to that item can trigger a cache miss and start regenerating that same item at the same time. This phenomenon, known as cache stampede, severely limits the performance of databases and web servers. A natural countermeasure to this issue is to let the processes that perform such requests to randomly ask for a regeneration before the expiration time of the item. In this paper we give optimal algorithms for performing such

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... ic early expirations. Our algorithms are theoretically optimal and have much better performances than other solutions used in real-world applications. *