基于指示符的缓存系统中的假否定感知
False Negative Awareness in Indicator-based Caching Systems
摘要：
诸如内容分发网络之类的分布式高速缓存系统经常经由轻量级近似指示符（例如，布隆过滤器），以有效地通知客户端每个数据可能缓存在哪里。虽然假阳性的迹象是必要的，很好地理解，大多数现有的作品假设没有假阴性的迹象。我们的工作说明了实际情况下，假阴性是不可避免的，忽略它们显着影响系统性能。具体来说，我们专注于假阴性诱导的指标陈旧，每当系统只定期检查指标，而不是立即报告缓存中的每一个变化。这样的场景自然发生，例如，在带宽受限的环境中或者当等待时间阻碍每个客户端获得更新的指示符的能力时。我们的工作介绍了新的假阴性意识的访问策略，不断估计的假阴性率，有时访问缓存，尽管负面的迹象。我们提出了最优的政策，同质设置，并提供近似保证我们的算法在异构环境中。我们进一步进行了广泛的模拟研究与多个真实系统的痕迹。我们表明，我们的假阴性意识算法产生的访问成本显着低于现有的方法或匹配这些方法的成本，同时需要一个数量级更少的资源（例如，高速缓存容量或带宽）。
英文摘要：
Distributed caching systems such as content distribution networks often advertise their content via lightweight approximate indicators (e.g., Bloom filters) to efficiently inform clients where each datum is likely cached. While false-positive indications are necessary and well understood, most existing works assume no false-negative indications. Our work illustrates practical scenarios where false-negatives are unavoidable and ignoring them significantly impacts system performance. Specifically, we focus on false-negatives induced by indicator staleness, which arises whenever the system advertises the indicator only periodically, rather than immediately reporting every change in the cache. Such scenarios naturally occur, e.g., in bandwidth-constraint environments or when latency impedes each client's ability to obtain an updated indicator. Our work introduces novel false-negative aware access policies that continuously estimate the false-negative ratio and sometimes access caches despite negative indications. We present optimal policies for homogeneous settings and provide approximation guarantees for our algorithms in heterogeneous environments. We further perform an extensive simulation study with multiple real system traces. We show that our false-negative aware algorithms incur a significantly lower access cost than existing approaches or match the cost of these approaches while requiring an order of magnitude fewer resources (e.g., caching capacity or bandwidth).
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
