Jul 2026· ACM Symposium on Parallelism in Algorithms and Architectures· pp. 116-128· 0 citations· 47 references
Computer Science
TL;DR
KDB is introduced, a novel persistent key-value data store (a concurrent index) with rich linearizable semantics that offers highly scalable performance across varied workloads thanks to its unique multiversioned architecture.
Abstract
In this paper, we introduce KDB, a novel persistent key-value data store (a concurrent index) with rich linearizable semantics. In contrast to state-of-the-art systems which offer only lookup and put/remove operations, KDB supports both snapshots (which are used by range scans) and atomic batch updates—put and remove operations that are executed atomically. Despite its rich semantics, our system offers highly scalable performance across varied workloads thanks to its unique multiversioned architecture. It features a hybrid lock-CAS synchronization mechanism that allows lookup operations and scans to proceed in a wait-free fashion. Under the hood, KDB maintains all key-value entries in persistent memory (PM) for failure atomicity, but it heavily relies on an efficient DRAM-backed multiversion index based on skip lists to hide the costs of accessing PM. For better PM utilization, entries are arranged in PM in preallocated arrays that occasionally undergo compaction.
Adopting replicated persistent key-value stores (RPKVSs) as metadata backends is becoming increasingly popular in modern large-scale storage systems. Conventional RPC-based KV replication is infamously subject to its replication overheads due to the inherent architectural mismatch between the application-level network stack and storage-prioritized operations. In this paper, we shift toward a new paradigm of storage-native block-based replication to fundamentally address the limitations of conventional replication. This shift is made possible by using widely deployed NVMe-oF technology to unify replication and storage efficiency under integrated block semantics. We present NoFDB, an NVMe-oF-enabled RPKVS design, that eliminates redundant index management and reduces replication latency, and introduces a set of system-level optimizations to address the challenges introduced by NVMe-oF and unlock its performance potential. Our evaluation shows that NoFDB improves random write throughput by up to 2.85 × and macrobenchmark throughput by up to 3.10 × over the best-performing baseline in each setting.
Liang Bao, Rui-Song Zhou, Hua Wang et al.· ACM Transactions on Architec...· 0 citations
Log-structured merge-tree (LSM-tree) key-value stores rely on caching to mitigate multi-component lookups and long tails, yet block and KP caches are prone to compactioninduced expiry, and all three cache types suffer from scan pollution under LRU eviction. We present AutoThermKV, a two-level in-memory architecture that decouples fast admission from hot-item protection. The front tier (HotFilter) uses a 64 Baligned bitmap/key/value page layout with Quick Space Reservation for near-constant admission cost; the back tier (HotCommitted) retains proven hot items via a lightweight LRU and a secondtouch promotion rule. Implemented atop RocksDB and evaluated on YCSB-like workloads with controllable temporal locality, AutoThermKV achieves up to 2.58 × throughput speedup, 2.60 × average-latency reduction, and tail-latency improvements of up to 20 × (p99) and 36 (p999) under modest memory budgets.
Yunfan Chi, E. Sha, Longshan Xu et al.· IEEE International Conferenc...· 0 citations
Disaggregated memory architecture has gained wide adoption in cloud and high-performance systems [18, 31, 43] due to its decoupled resource model, elasticity, and low-latency access. In such architectures, transaction mechanisms must ensure atomic and consistent access to remote memory. Prior designs use array-based version structures to improve locality, but their fixed capacity introduces false conflicts, especially for long transactions that require accessing historical versions, limiting concurrency and throughput. We present MiTDM, a transaction system tailored for disaggregated memory environments. MiTDM introduces a hierarchical block version chain that combines the benefits of array and chained structures, supporting dynamic version expansion while maintaining low-latency access. A lightweight Block Index Table accelerates remote reads, and an asynchronous index update mechanism synchronizes indexes across nodes with minimal overhead. To manage version growth, MiTDM employs a hybrid garbage collection strategy aware of transaction states, enabling safe reclamation and reuse of version slots, particularly in hot spots. A one-sided optimistic transaction protocol ensures consistency and atomicity under high concurrency. Experimental results on a disaggregated memory cluster show that MiTDM outperforms state-of-the-art systems. Under the TPC-C workload with 128 clients, it achieves up to 80.1% higher throughput compared to FaRMV2 and 42.7% higher than Motor, while significantly reducing P50 and P99 latencies.
Ao-Xin Wei, Jin-Tian Wu, Jian Zhou et al.· 0 citations
On EnterpriseRAG-Bench, MEMONDEMAND outperforms the strongest published LB#1 result at every evaluated scale from 10M tokens through the complete 618M- token collection, and results on FinanceBench, HotpotQA, and FRAMES further show strong performance across financial, multi-hop, and fact-retrieval settings.
Xin-Yuan Song, Bo-Wen Zhu, H. Haque et al.· 0 citations
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