AC-Cache: A Memory-Efficient Caching System for Small Objects via Exploiting Access Correlations

In-memory key-value (KV) caching bridges the performance gap between high-performance networks and disk devices. However, prior in-memory KV caching systems either consider large objects or introduce additional memory overhead. In this paper, we conduct a systematic analysis over 56 production traces, and make three observations: (i) small objects dominate the traces and data accesses are highly skewed; (ii) the hotness of objects keeps stable across days; and (iii) the multi-get operation that retrieves multiple objects from the same node incurs much shorter tail latency than purely using the single-get operation.