Pyramid: A Layered Sharding Blockchain System
Pyramid: A Layered Sharding Blockchain System
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DOI：
10.1109/infocom42981.2021.9488747
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发表时间：
2021-05
期刊：
影响因子：
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通讯作者：
Zicong Hong;Song Guo;Peng Li;Wuhui Chen
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文献类型：
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作者：
Zicong Hong;Song Guo;Peng Li;Wuhui Chen
分片可以显着提高区块链的可扩展性，通过将节点划分为称为分片的小组，可以并行处理事务。然而，所有现有的分片系统都采用完全分片，即，碎片是孤立的。它增加了额外的开销来保证跨分片事务的原子性和一致性，并严重降低了分片性能。在本文中，我们提出了Pyramid，第一个分层分片区块链系统，其中一些分片可以存储多个分片的完整记录，因此可以在这些分片内部处理和验证跨分片交易。在提交跨分片事务时，为了实现相关分片之间的一致性，提出了一种基于多个分片协作的分层分片共识。与将每个跨分片事务拆分为多个子事务并花费多个共识轮来提交的完全分片相比，分层分片共识可以在一轮中提交跨分片事务。此外，从理论上分析了不同分片结构的分层分片的安全性、可扩展性和性能。最后，我们实现了一个Pyramid的原型，其评估结果表明，与最先进的完整的分片系统相比，Pyramid可以提高2.95倍的事务吞吐量在17个分片和3500个节点的系统。
Sharding can significantly improve the blockchain scalability, by dividing nodes into small groups called shards that can handle transactions in parallel. However, all existing sharding systems adopt complete sharding, i.e., shards are isolated. It raises additional overhead to guarantee the atomicity and consistency of cross-shard transactions and seriously degrades the sharding performance. In this paper, we present Pyramid, the first layered sharding blockchain system, in which some shards can store the full records of multiple shards thus the cross-shard transactions can be processed and validated in these shards internally. When committing cross-shard transactions, to achieve consistency among the related shards, a layered sharding consensus based on the collaboration among several shards is presented. Compared with complete sharding in which each cross-shard transaction is split into multiple sub-transactions and cost multiple consensus rounds to commit, the layered sharding consensus can commit cross-shard transactions in one round. Furthermore, the security, scalability, and performance of layered sharding with different sharding structures are theoretically analyzed. Finally, we implement a prototype for Pyramid and its evaluation results illustrate that compared with the state-of-the-art complete sharding systems, Pyramid can improve the transaction throughput by 2.95 times in a system with 17 shards and 3500 nodes.