On the Correctness of Speculative Consensus

TL;DR

This paper presents PoE, a novel speculative consensus protocol that reduces latency and communication costs in resilient data management systems by enabling early execution and proof of successful execution.

Contribution

The paper introduces PoE, a new consensus protocol combining speculative execution, proof-of-executions, and a single-round check-commit to enhance performance and efficiency.

Findings

PoE achieves lower latency compared to traditional protocols.

PoE reduces communication costs with a single-round check-commit.

PoE is suitable for high-performance resilient data management systems.

Abstract

The introduction of Bitcoin fueled the development of blockchain-based resilient data management systems that are resilient against failures, enable federated data management, and can support data provenance. The key factor determining the performance of such resilient data management systems is the consensus protocol used by the system to replicate client transactions among all participants. Unfortunately, existing high-throughput consensus protocols are costly and impose significant latencies on transaction processing, which rules out their usage in responsive high-performance data management systems. In this work, we improve on this situation by introducing the Proof-of-Execution consensus protocol (PoE), a consensus protocol designed for high-performance low-latency resilient data management. PoE introduces speculative execution, which minimizes latencies by starting execution before consensus is reached, and PoE introduces proof-of-executions to guarantee successful execution to clients. Furthermore, PoE introduces a single-round check-commit protocol to reduce the overall communication costs of consensus. Hence, we believe that PoE is a promising step towards flexible general-purpose low-latency resilient data management systems.