Fresh Caching of Dynamic Content Over the Wireless Edge
Fresh Caching of Dynamic Content Over the Wireless Edge
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DOI：
10.1109/tnet.2022.3170245
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发表时间：
2022-10
期刊：
影响因子：
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通讯作者：
B. Abolhassani;John Tadrous;A. Eryilmaz;E. Yeh
中科院分区：
文献类型：
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作者：
B. Abolhassani;John Tadrous;A. Eryilmaz;E. Yeh
我们引入了一个框架和证明有效的计划，在（前端）本地缓存的内容，是受“动态”更新（后端）数据库的“新鲜”缓存。我们首先制定了硬缓存约束的问题，这种设置，这很快成为棘手的，由于有限的缓存。为了绕过这一挑战，我们首先提出了一个灵活的基于时间的驱逐模型，以获得平均系统成本函数，该函数测量系统的成本，由于服务的老化内容，除了常规的缓存未命中成本。接下来，我们解决了缓存不受约束的情况下，这揭示了刷新动态和流行的内容如何影响最佳缓存。然后，我们将我们的方法扩展到一个软缓存约束的版本，在那里我们可以保证该高速缓存的使用是有限的任意高的概率。相应的解决方案揭示了一个有趣的见解，“是否缓存一个项目或不在本地缓存？”主要取决于它的流行程度和频道可靠性，而“缓存的项目在驱逐之前应该在该高速缓存中保存多久？”主要取决于它的刷新率。此外，我们调查的成本缓存节省权衡和证明，可以获得大量的缓存收益，同时也渐近实现最低成本的数据库大小的增长。
We introduce a framework and provably-efficient schemes for ‘fresh’ caching at the (front-end) local cache of content that is subject to ‘dynamic’ updates at the (back-end) database. We start by formulating the hard-cache-constrained problem for this setting, which quickly becomes intractable due to the limited cache. To bypass this challenge, we first propose a flexible time-based-eviction model to derive the average system cost function that measures the system’s cost due to the service of aging content in addition to the regular cache miss cost. Next, we solve the cache-unconstrained case, which reveals how the refresh dynamics and popularity of content affect optimal caching. Then, we extend our approach to a soft-cache-constrained version, where we can guarantee that the cache use is limited with arbitrarily high probability. The corresponding solution reveals the interesting insight that ‘whether to cache an item or not in the local cache?’ depends primarily on its popularity level and channel reliability, whereas ‘how long the cached item should be held in the cache before eviction?’ depends primarily on its refresh rate. Moreover, we investigate the cost-cache saving trade-offs and prove that substantial cache gains can be obtained while also asymptotically achieving the minimum cost as the database size grows.