Sui Lutris: A Blockchain Combining Broadcast and Consensus (2310.18042v5)

Abstract: Sui Lutris is the first smart-contract platform to sustainably achieve sub-second finality. It achieves this significant decrease by employing consensusless agreement not only for simple payments but for a large variety of transactions. Unlike prior work, Sui Lutris neither compromises expressiveness nor throughput and can run perpetually without restarts. Sui Lutris achieves this by safely integrating consensuless agreement with a high-throughput consensus protocol that is invoked out of the critical finality path but ensures that when a transaction is at risk of inconsistent concurrent accesses, its settlement is delayed until the total ordering is resolved. Building such a hybrid architecture is especially delicate during reconfiguration events, where the system needs to preserve the safety of the consensusless path without compromising the long-term liveness of potentially misconfigured clients. We thus develop a novel reconfiguration protocol, the first to provably show the safe and efficient reconfiguration of a consensusless blockchain. Sui Lutris is currently running in production and underpins the Sui smart-contract platform. Combined with the use of Objects instead of accounts it enables the safe execution of smart contracts that expose objects as a first-class resource. In our experiments Sui Lutris achieves latency lower than 0.5 seconds for throughput up to 5,000 certificates per second (150k ops/s with transaction blocks), compared to the state-of-the-art real-world consensus latencies of 3 seconds. Furthermore, it gracefully handles validators crash-recovery and does not suffer visible performance degradation during reconfiguration.

• The paper presents Lutris, a hybrid blockchain that achieves sub-second finality and high throughput by combining broadcast and consensus methods.
• The paper employs a dual processing model where single-writer operations use broadcast and multi-writer operations use consensus to ensure safety.
• The paper demonstrates robust performance with less than 0.5 sec latency for 5,000 certificates per second and maintains resilience under validator crashes.

Analysis of "Lutris: A Blockchain Combining Broadcast and Consensus"

The paper "Lutris: A Blockchain Combining Broadcast and Consensus" presents a comprehensive overview of Lutris, a blockchain system designed to achieve sub-second finality while integrating broadcast and consensus techniques. This paper addresses the primary challenges in blockchain design, particularly balancing latency, throughput, and consistency, without sacrificing expressiveness.

Overview

Lutris is characterized by its dual processing approach where it employs consensusless agreement for single-writer operations, relying on broadcast functions, and consensus-based methods for multi-writer operations. This hybrid model facilitates efficient transaction processing while ensuring safety and consistency. A critical component of Lutris is its utilization of the Move programming language, allowing smart contracts to safely execute with objects as first-class resources, augmenting expressiveness and functionality.

Numerical Results and Performance

The paper provides robust performance metrics that underline Lutris's efficiency. For instance, Lutris achieves latency lower than 0.5 seconds for up to 5,000 certificates per second (150,000 operations per second with bundling), a marked improvement over conventional consensus protocols with latencies around 3 seconds. The system also demonstrates resilience to validator crashes, maintaining performance without visible degradation. This performance benchmark reflects the system's capacity to operate at scales demanded by modern smart contract platforms.

Theoretical and Practical Implications

The integration of consensusless protocols in a production blockchain is unprecedented, given their historical limitations, such as only supporting asset transfers and being susceptible to client misconfiguration. Lutris’s design demonstrates a viable pathway toward scalable, low-latency blockchains by leveraging this hybrid consensus model. The theoretical implications are particularly significant as they introduce novel approaches to reconfiguration, which enhance system robustness and client usability.

Reconfiguration and Checkpoint Protocols

Lutris incorporates an innovative reconfiguration protocol, ensuring system security during validator changes without disrupting ongoing operations. The checkpointing mechanism efficiently preserves the transaction history, facilitating synchronization and audit functions, thereby supporting the long-term stability of the blockchain.

Future Directions

The paper opens avenues for further research in optimizing blockchain latencies and throughput while exploring the broader application of consensusless protocols in different blockchain contexts. Lutris's architecture provides a foundation for future developments aiming to decentralize processing further and minimize dependency on full consensus methodologies.

Conclusion

The paper contributes significantly to blockchain research by addressing latency and performance challenges in smart-contract platforms. Lutris establishes a scalable and sustainable model for blockchain systems, encouraging future exploration of hybrid consensus mechanisms. While the improvements in latency and throughput are substantial, ongoing research may focus on expanding capabilities and refining the integration of consensusless systems. This research sets a precedent for future blockchain architectures aiming for rapid, secure, and reliable transaction processing.