Epoch-based Optimistic Concurrency Control in Geo-replicated Databases

2026-02-24

AI Summary

This work addresses the challenge of efficiently supporting serializable transactions in geo-distributed databases under high network latency, where excessive coordination severely limits performance. The authors propose Minerva, a system that decouples data propagation from transaction commit through epoch-based asynchronous replication and combines optimistic concurrency control with deterministic re-execution to enable high-throughput, coordination-free, multi-master serializable transactions. Its key innovation lies in integrating epoch-based replication with deterministic re-execution, modeling conflicts via a conflict graph and optimizing transaction commits using a maximum-weight independent set algorithm to substantially reduce re-execution overhead. Experimental results on the TPC-C benchmark demonstrate that Minerva achieves over 3× higher throughput than existing systems under typical conditions and up to 2.8× improvement in high-latency scenarios.

Technology Category

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

Application Category

• Security and Privacy: Data transparency and provenance
• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Graph Algorithms and Modeling for the Web: Efficient manipulation of static and dynamic Web-related graphs

Abstract

Geo-distribution is essential for modern online applications to ensure service reliability and high availability. However, supporting high-performance serializable transactions in geo-replicated databases remains a significant challenge. This difficulty stems from the extensive over-coordination inherent in distributed atomic commitment, concurrency control, and fault-tolerance replication protocols under high network latency. To address these challenges, we introduce Minerva, a unified distributed concurrency control designed for highly scalable multi-leader replication. Minerva employs a novel epoch-based asynchronous replication protocol that decouples data propagation from the commitment process, enabling continuous transaction replication. Optimistic concurrency control is used to allow any replicas to execute transactions concurrently and commit without coordination. In stead of aborting transactions when conflicts are detected, Minerva uses deterministic re-execution to resolve conflicts, ensuring serializability without sacrificing performance. To further enhance concurrency, we construct a conflict graph and use a maximum weight independent set algorithm to select the optimal subset of transactions for commitment, minimizing the number of re-executed transactions. Our evaluation demonstrates that Minerva significantly outperforms state-of-the-art replicated databases, achieving over $3\times$ higher throughput in scalability experiments and $2.8\times$ higher throughput during a high network latency simulation with the TPC-C benchmark.

Problem

• geo-replicated databases
• serializable transactions
• optimistic concurrency control
• high network latency
• over-coordination

Innovation

• epoch-based replication
• optimistic concurrency control
• deterministic re-execution
• multi-leader replication
• conflict graph