标题： 以太坊智能合约的最小 gas 限制和使用的 gas 的去神秘化及接近完美的估计 显示英文标题

标题： Demystification and Near-perfect Estimation of Minimum Gas Limit and Gas Used for Ethereum Smart Contracts

摘要： 以太坊区块链有一个\emph{气体系统}，它将操作与燃气单位的成本关联起来。 该系统两个核心概念是由交易发起者分配的\emph{gas 限制}和由交易执行的\emph{使用的气体}。 前者是一个预算，在交易执行完成之前不能耗尽；否则，执行会失败。 因此，确定一个确保交易不会因缺乏燃气而中止的\emph{最小气体限制}显得尤为重要。 尽管这一概念在实际中有重要意义，但它尚未得到适当解决。 在文献中，燃气使用量和最小燃气限制被混淆了。 本文提出了一种精确的最小燃气限制概念，以及它如何可能不同于交易使用的燃气；通过以太坊区块链的实际交易进行定量研究也证明了这一点。 另一个重要贡献是对这两个指标提出了相当精确的估计器。 同样，这些概念之间的混淆导致了仅针对交易使用的燃气创建估计器。 我们演示了以太坊区块链状态（区块后）的最小燃气限制$t$可以作为区块$t + \Delta$上交易执行的近乎完美的估算值，其中$\Delta \leq 11$；对于估算燃气使用量也是如此。 这些精确的估算器对帮助用户预测交易的燃气预算和开发人员优化智能合约非常有价值；过高或过低估算燃气使用量和最小燃气限制会导致许多实际问题。 总体而言，本文为区块链开发者和用户提供了关于燃气系统如何运作的重要参考。 显示英文摘要

摘要： The Ethereum blockchain has a \emph{gas system} that associates operations with a cost in gas units. Two central concepts of this system are the \emph{gas limit} assigned by the issuer of a transaction and the \emph{gas used} by a transaction. The former is a budget that must not be exhausted before the completion of the transaction execution; otherwise, the execution fails. Therefore, it seems rather essential to determine the \emph{minimum gas limit} that ensures the execution of a transaction will not abort due to the lack of gas. Despite its practical relevance, this concept has not been properly addressed. In the literature, gas used and minimum gas limit are conflated. This paper proposes a precise notion of minimum gas limit and how it can differ from gas used by a transaction; this is also demonstrated with a quantitative study on real transactions of the Ethereum blockchain. Another significant contribution is the proposition of a fairly precise estimator for each of the two metrics. Again, the confusion between these concepts has led to the creation of estimators only for the gas used by a transaction. We demonstrate that the minimum gas limit for the state of the Ethereum blockchain (after the block) $t$ can serve as a near-perfect estimation for the execution of the transaction at block $t + \Delta$, where $\Delta \leq 11$; the same holds for estimating gas used. These precise estimators can be very valuable in helping the users predict the gas budget of transactions and developers in optimising their smart contracts; over and underestimating gas used and minimum gas limit can lead to a number of practical issues. Overall, this paper serves as an important reference for blockchain developers and users as to how the gas system really works.