Consensus protocols are currently the bottlenecks that prevent blockchain systems from scaling. However, we argue that transaction execution is also important to the performance and security of blockchains. In other words, there are ample opportunities to speed up and further secure blockchains by reducing the cost of transaction execution. Our goal is to understand how much we can speed up blockchains by exploiting transaction concurrency available in blockchain workloads. To this end, we first analyze historical data of seven major public blockchains, namely Bitcoin, Bitcoin Cash, Litecoin, Dogecoin, Ethereum, Ethereum Classic, and Zilliqa. We consider two metrics for concurrency, namely the single-transaction conflict rate per block, and the group conflict rate per block. We find that there is more concurrency in UTXO-based blockchains than in account-based ones, although the amount of concurrency in the former is lower than expected. Another interesting finding is that some blockchains with larger blocks have more concurrency than blockchains with smaller blocks. Next, we propose an analytical model for estimating the transaction execution speed-up given an amount of concurrency. Using results from our empirical analysis, the model estimates that 6x speed-ups in Ethereum can be achieved if all available concurrency is exploited.

中文翻译：

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利用交易并发加速区块链

共识协议是目前阻止区块链系统扩展的瓶颈。然而，我们认为交易执行对区块链的性能和安全性也很重要。换句话说，有很多机会通过降低交易执行成本来加速和进一步保护区块链。我们的目标是通过利用区块链工作负载中可用的交易并发来了解我们可以在多大程度上加速区块链。为此，我们首先分析了比特币、比特现金、莱特币、狗狗币、以太坊、以太经典、Zilliqa 七大公链的历史数据。我们考虑并发性的两个指标，即每个区块的单笔交易冲突率和每个区块的组冲突率。我们发现基于 UTXO 的区块链比基于账户的区块链具有更多的并发性，尽管前者的并发量低于预期。另一个有趣的发现是，一些具有较大块的区块链比具有较小块的区块链具有更多的并发性。接下来，我们提出了一个分析模型，用于估计给定并发量的交易执行加速。使用我们的实证分析结果，该模型估计，如果利用所有可用的并发性，可以在以太坊中实现 6 倍的加速。我们提出了一个分析模型，用于估计给定并发量的交易执行加速。使用我们的实证分析结果，该模型估计，如果利用所有可用的并发性，可以在以太坊中实现 6 倍的加速。我们提出了一个分析模型，用于估计给定并发量的交易执行加速。使用我们的实证分析结果，该模型估计，如果利用所有可用的并发性，可以在以太坊中实现 6 倍的加速。