While many researchers adopt a sharding approach to design scaling blockchains, few works have studied the transaction placement problem incurred by sharding protocols. The widely-used hashing placement algorithm renders an overwhelming portion of transactions as cross-shard. In this paper, we analyze the high cost of cross-shard transactions and reveal that most Bitcoin transactions have simple dependencies and can become single-shard under a placement algorithm taking transaction dependencies into account. In addition, we perform a case study of OptChain, which is the state-of-the-art transaction placement algorithm for sharded blockchains, and find a shortcoming of it. A simple fix is proposed, and our evaluation results demonstrate that the proposed fix effectively helps OptChain overcome the shortcoming and significantly improve the system performance under a special workload. The authors of OptChain made some revisions to the algorithm description after noticing our work. Their updated algorithm does not exhibit the shortcoming under the workloads employed by this paper.
翻译:虽然许多研究人员在设计缩放链时采取了一种碎片化的方法,但很少有人研究过碎片化程序引起的交易安置问题。 广泛使用的散列算法使绝大多数交易成为交叉碎片化的交易。 在本文中,我们分析了交叉碎化交易的高昂成本,并揭示了大多数比特币交易具有简单的依赖性,并且可以在考虑到交易依赖性的情况下,在一种配置算法下变成单一碎片。此外,我们还对Optchain进行了案例研究,这是硬化块化程序的最新交易安置算法,并找出了缺陷。提出了简单的方法,我们的评价结果表明,拟议的固定方法有效地帮助Optchain克服了缺陷,并在特殊工作量下大大改进了系统绩效。Optchain的作者在注意到我们的工作之后对算法描述做了一些修改。他们更新的算法并没有显示本文使用的工作量下的缺陷。