The Sui Mysticeti Upgrade Demystified

The Mysticeti protocol that was introduced in July of this year is aimed at enhancing the efficiency and performance of Sui Network. Named after the Mysticeti suborder of whales, it symbolizes the power and capability the protocol brings to the chain. In this article, we'll look into its components and benefits.

The Sui Mysticeti Upgrade represents a cutting-edge approach to blockchain transaction processing, blending innovative consensus mechanisms with a unique architecture designed to enhance both speed and efficiency.

By introducing new protocols and rethinking how transactions are validated and finalized, Sui tackles common performance bottlenecks found in traditional blockchain systems. This architecture showcases a forward-looking strategy to handle the growing demands of decentralized applications while maintaining a focus on reliability and scalability.

Sui's Hybrid Transaction Processing Strategy

Sui employs a hybrid strategy for transaction processing. It features a consensus pathway for transactions requiring the agreement of a majority of validators and a "fast path" for transactions that can be executed without consensus. For instance, tasks like "asset transfers, payments, or NFT minting"—described as typical workloads—can be finalized via the fast path before reaching consensus, achieving lower latency.

Fast Path Transactions and Optimistic Finality

In the fast path, Sui utilizes a technique known as "optimistic finality." This approach allows transactions to be executed once they have received votes from a sufficient number of validators. Although they can still be reversed later if they are found to be invalid, the responsibility lies with the validators, transactions finalized through the consensus path are guaranteed to be accurate and immutable.

MYSTICETI Consensus Protocols: Enhancing Latency Reduction

Two critical solutions have been introduced: 1) MYSTICETI-C, a consensus protocol based on a threshold logical clock DAG of blocks, which commits each block as soon as it becomes determinable. 2) MYSTICETI-FPC adds a fast commit path designed to reduce latency in asset transfers further. Sui’s architecture relies on DAGs to structure the sequence of blockchain transactions. These protocols improve latency compared to previous methods by sidestepping the need for explicit block certification. Additionally, they employ a new commit rule that allows blocks to be finalized immediately upon validation without waiting for other blocks to be certified.

Uncertified DAG-Based Consensus and Latency Implications

The key technological shift from earlier versions of Sui is that Mysticeti utilizes an uncertified DAG-based consensus protocol, in contrast to the certified DAG-based protocol. This change significantly reduces latency from 1900ms to 400ms. The shift to an uncertified DAG-based consensus protocol is expected to reduce latency for transactions requiring consensus because it removes the delays associated with explicit block certification.

Balancing Latency for Consensus and Owned Object Transactions

The paper also notes that this new approach could lead to increased latency for transactions involving owned objects—transactions that concern only a single user’s assets and do not impact shared resources. These transactions bypass the consensus mechanism and are executed directly. The potential latency increase might stem from the additional overhead introduced by the post-consensus checkpoint mechanism, although the paper does not quantify the extent of this increase. Despite the possibility of slightly higher latency for owned object transactions, the overall expectation is that the reduced latency for consensus-based transactions will more than compensate. Given that consensus-based transactions tend to be more complex and time-intensive, even a modest reduction in their latency could greatly enhance the system's overall performance.

Conclusion

Sui’s innovative hybrid transaction processing strategy, combining both a consensus pathway and a fast path, offers significant performance improvements for blockchain transactions.

By leveraging optimistic finality for simpler workloads and the MYSTICETI protocols for reducing latency in complex operations, Sui enhances both efficiency and scalability. This new model of consensus and fast path transaction development clears the way for Sui to be one of the leading protocols in regard to speed. This is on par with their vision to one day be able to have enough speed to support projects are real time multiplayer video games which is something that hasn’t been properly solved since gaming has been a topic of interest for the industry.

The shift to an uncertified DAG-based consensus protocol, while introducing slight trade-offs in certain cases, is a pivotal step in lowering latency for transactions requiring consensus. Though there may be minor increases in latency for owned object transactions, the overall architecture is designed to prioritize system-wide performance gains, especially for more intricate, consensus-dependent tasks. This balanced approach positions Sui as a forward-thinking solution for blockchain platforms seeking to optimize both speed and reliability.