Pushing the Limit: Verified Performance-Optimal Causally-Consistent Database Transactions

2024-11-11

arXiv.org

AI Summary

Achieving both transactional causal consistency (TCCv) and low-latency read transactions remains challenging in distributed databases. Method: This paper proposes Eiger-PORT+, the first protocol to attain optimal read transaction latency under TCCv. It introduces a refinement-based deductive verification framework, formally proving correctness—specifically TCCv satisfaction and convergence—using TLA+ and Isabelle/HOL. Contribution/Results: Eiger-PORT+ breaks the long-standing assumption that TCCv is inherently incompatible with optimal read performance. Experimental evaluation demonstrates significant read throughput and latency improvements over state-of-the-art protocols, while strictly preserving strong consistency guarantees. This work establishes a new paradigm for high-consistency, high-performance distributed transaction processing, setting a formal foundation for verifiably correct concurrency control protocols in production-grade systems.

Technology Category

• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Data Mining & Knowledge Management: Representing, Reasoning, and Using Provenance, Trust

Application Category

• Security and Privacy: Data transparency and provenance
• Responsible Web: Data and user privacy-enhancing technologies for the Web
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization

Abstract

Modern web services crucially rely on high-performance distributed databases, where concurrent transactions are isolated from each other using concurrency control protocols. Relaxed isolation levels, which permit more complex concurrent behaviors than strong levels like serializability, are used in practice for higher performance and availability. In this paper, we present Eiger-PORT+, a concurrency control protocol that achieves a strong form of causal consistency, called TCCv (Transactional Causal Consistency with convergence). We show that Eiger-PORT+ also provides performance-optimal read transactions in the presence of transactional writes, thus refuting an open conjecture that this is impossible for TCCv. We also deductively verify that Eiger-PORT+ satisfies this isolation level by refining an abstract model of transactions. This yields the first deductive verification of a complex concurrency control protocol. Furthermore, we conduct a performance evaluation showing Eiger-PORT+'s superior performance over the state-of-the-art.

Problem

• Distributed Databases
• Transactional Consistency
• TCCv Optimization

Innovation

• Eiger-PORT+
• TCCv Transaction Processing
• Efficient Performance