Brook-2PL: Tolerating High Contention Workloads with A Deadlock-Free Two-Phase Locking Protocol

2025-08-25

AI Summary

Under high-contention workloads, conventional concurrency control mechanisms suffer from frequent transaction aborts and deadlocks due to hotspots. To address this, this paper proposes a deadlock-free two-phase locking (2PL) protocol. Our approach comprises two key innovations: (1) constructing an SLW-Graph for static dependency analysis to provably eliminate cyclic wait conditions; and (2) introducing partial transaction splitting coupled with fine-grained early lock release, which reduces lock-holding duration while preserving serializability and eliminating cascading aborts. Evaluated on the TPC-C benchmark, the protocol achieves a 2.86× average throughput improvement and reduces p95 tail latency by 48%, significantly outperforming state-of-the-art protocols.

Technology Category

• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Data Mining & Knowledge Management: Scalability, Parallel & Distributed Systems

Application Category

• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Web evaluation methodologies and metrics

Abstract

The problem of hotspots remains a critical challenge in high-contention workloads for concurrency control (CC) protocols. Traditional concurrency control approaches encounter significant difficulties under high contention, resulting in excessive transaction aborts and deadlocks. In this paper, we propose Brook-2PL, a novel two-phase locking (2PL) protocol that (1) introduces SLW-Graph for deadlock-free transaction execution, and (2) proposes partial transaction chopping for early lock release. Previous methods suffer from transaction aborts that lead to wasted work and can further burden the system due to their cascading effects. Brook-2PL addresses this limitation by statically analyzing a new graph-based dependency structure called SLW-Graph, enabling deadlock-free two-phase locking through predetermined lock acquisition. Brook-2PL also reduces contention by enabling early lock release using partial transaction chopping and static transaction analysis. We overcome the inherent limitations of traditional transaction chopping by providing a more flexible chopping method. Evaluation using both our synthetic online game store workload and the TPC-C benchmark shows that Brook-2PL significantly outperforms state-of-the-art CC protocols. Brook-2PL achieves an average speed-up of 2.86x while reducing tail latency (p95) by 48% in the TPC-C benchmark.

Problem

• Addressing high contention workloads in concurrency control protocols
• Eliminating deadlocks and reducing transaction aborts in 2PL
• Enabling early lock release through partial transaction chopping

Innovation

• SLW-Graph enables deadlock-free two-phase locking
• Partial transaction chopping allows early lock release
• Static analysis of dependency structure prevents deadlocks