Thunderbolt: Concurrent Smart Contract Execution with Non-blocking Reconfiguration for Sharded DAGs
Junchao Chen, Alberto Sonnino, Lefteris Kokoris-Kogias, Mohammad Sadoghi

TL;DR
Thunderbolt introduces a sharding architecture for DAG-based blockchains that enables nonblocking reconfiguration and dynamic transaction scheduling, significantly improving throughput and system resilience without relying on pre-declared read/write sets.
Contribution
It presents a novel sharding design with dynamic concurrency control and nonblocking reconfiguration for DAG-based smart contract systems, addressing key limitations of existing approaches.
Findings
50x throughput improvement over serial execution
Effective dynamic dependency resolution at runtime
Nonblocking shard reconfiguration enhances system resilience
Abstract
Sharding has emerged as a critical technique for enhancing blockchain system scalability. However, existing sharding approaches face unique challenges when applied to Directed Acyclic Graph (DAG)-based protocols that integrate expressive smart contract processing. Current solutions predominantly rely on coordination mechanisms like 2PC and require transaction read/write sets to optimize parallel execution. These requirements introduce two fundamental limitations: 1) additional coordination phases incur latency overhead, and 2) pre-declaration of read/write sets proves impractical for Turing-complete smart contracts with dynamic access patterns. This paper presents Thunderbolt, a novel sharding architecture for both single-shard transactions (Single-shard TXs) and cross-shard transactions (Cross-shard TXs) and enables nonblocking reconfiguration to ensure system liveness. Our design…
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Taxonomy
TopicsComputability, Logic, AI Algorithms · Scientific Computing and Data Management
