Remora: Scale-out Deterministic Execution for Smart Contracts

2026-07-02

AI Summary

This work addresses the performance bottleneck in blockchain execution layers caused by the inability of single-node validators to meet the growing demands of smart contract execution. To overcome this limitation, the authors propose a horizontally scalable, deterministic execution engine featuring an asymmetric architecture that combines centralized scheduling with distributed execution. The design decouples consensus from execution through a stateless-stateful separation mechanism and enforces execution determinism via a strict ownership model based on object versioning. Furthermore, a locality-aware and load-balanced scheduling strategy is introduced to elastically adapt to bursty workloads and dynamic access patterns. Experimental results demonstrate that the system achieves up to 250,000 transactions per second—three times higher throughput than existing solutions—with latency reductions of up to 5 milliseconds, aligning execution performance with modern consensus protocols.

Abstract

Modern blockchains rely on a modular architecture that decouples consensus from execution. Recent advances in consensus algorithms have shifted the bottleneck to the execution layer, which must deterministically follow the consensus order and handle increasingly complex, compute-intensive smart contracts. We identify that single-node validators cannot keep up, motivating the need for a scale-out design. We design Remora, a scale-out smart contract execution engine. Remora adopts an efficient asymmetric architecture with centralized transaction dispatching and distributed execution, and depends on an object versioning scheme with a strict ownership model to guarantee deterministic scale-out execution. Remora achieves up to 3x throughput improvement compared to state-of-the-art deterministic execution schemes, scales up to 250k TPS, matching modern consensus performance, and reduces latency by up to 5ms. We also show that Remora elastically adapts to bursty workloads and dynamic access patterns using real-world traces. Remora's main performance benefits come from a novel stateless-stateful separation during smart contract execution, which overlaps the execution of state-independent tasks with consensus, and a new locality-aware and load-balanced scheduling scheme.

Problem

• deterministic execution
• smart contracts
• scale-out
• blockchain
• execution bottleneck

Innovation

• scale-out execution
• deterministic smart contracts
• stateless-stateful separation
• object versioning
• load-balanced scheduling