MethodId Optimization

When transactions are executed by the Ethereum Virtual Machine (EVM), the accompanying calldata, which specifies the contract function to be executed, incurs gas fees. These fees are calculated based on the calldata size, with 0 bytes costing 4 gas units and non-0 bytes costing 16 gas units. This pricing structure encourages the efficient use of calldata to reduce transaction costs, especially in contracts with high transaction volumes or complex operations.

The first four bytes of calldata, known as the MethodId, identify the specific contract function to be executed. Optimizing function names to increase the number of 0 bytes in the MethodId can reduce gas costs. 这种优化对需要频繁调用的函数的影响尤为明显，因为它直接影响了合约间的整体交互的 gas 效率。

We can optimize function names using this tool: Online Function Name Optimizer.

代码演示

Below are examples of standard function calls and their optimized counterparts using methodId optimization.

contract ExampleContract {
    // gas: 5285
    function exampleFunction() external {
    }
}

contract OptimizedExampleContract {
    // gas: 5265
    function exampleFunction_X8p() external {
    }
}

关于 gas 优化的建议：

🌟 By refining function names to maximize the occurrence of 0 bytes in the MethodId, we can decrease the gas expenses. （需要注意的是，这种方法会在一定程度上影响代码的可读性。）