Survey: Sharding in Blockchains

Abstract

The Blockchain technology, featured with its decentralized tamper-resistance based on a Peer-to-Peer network, has been widely applied in financial applications, and even further been extended to industrial applications. However, the weak scalability of traditional Blockchain technology severely affects the wide adoption due to the well-known trillema of decentralization-security-scalability in Blockchains. In regards to this issue, a number of solutions have been proposed, targeting to boost the scalability while preserving the decentralization and security. They range from modifying the on-chain data structure and consensus algorithms to adding the off-chain technologies. Therein, one of the most practical methods to achieve horizontal scalability along with the increasing network size is sharding, by partitioning network into multiple shards so that the overhead of duplicating communication, storage, and computation in each full node can be avoided. This paper presents a survey focusing on sharding in Blockchains in a systematic and comprehensive way. We provide detailed comparison and quantitative evaluation of major sharding mechanisms, along with our insights analyzing the features and restrictions of the existing solutions. We also provide theoretical upper-bound of the throughput for each considered sharding mechanism. The remaining challenges and future research directions are also reviewed.

Performance Evaluation of Blockchain Systems: A Systematic Survey

“…Note that this survey focuses only on blockchain performance evaluation, and solutions for blockchain performance or scalability improvement are not discussed. Interested readers may refer to the published surveys of performance improvement solutions for blockchain [41]- [46] listed in Table 1.…”

Blockchain-Based Decentralized Virtual Power Plants of Small Prosumers

“…When such a VPP reaches 150 members, the throughput is close to 1, which means that we reached the maximum number of members that an intermediary VPP can be sustained on a public blockchain such as Ethereum. Anyway, the allocation of prosumers in intermediary VPPs goes hand in hand with blockchain sharding mechanisms [48] which can be a solution for increasing the transaction throughput. In this case, the energy transactions among prosumers are isolated to the level of a shard delimitated by the membership in a VPP.…”

The Role of Blockchain to Fight Against COVID-19

“…Possible Solutions: To improve transaction throughput and make blockchain scalable, researchers are working on innovative solutions, like sharding [23] and layer-2 scalability solutions [24]. Sharding is a way to achieve network-wide scalability such that a rapidly growing blockchain network can be logically divided into groups, called shards.…”