非零余额

Initializing a storage variable from zero to a non-zero value is one of the most gas-intensive operations a contract can perform. It requires a total of 22,100 gas, including 20,000 gas for changing the value from zero to non-zero and 2,100 gas for cold storage access.

这就是为什么OpenZeppelin的重入保护机制使用1和2而不是0和1来标记函数的活跃和非活跃状态。 Changing a storage variable from one non-zero value to another only costs 5,000 gas.

在ERC20的实际应用中，应该避免ERC20代币余额降至零。 始终在余额中保留少量代币。 这种方法可以实现类似的效果。 If an address frequently empties and reloads its account balance, it will lead to many zero-to-one writes, which are costly in terms of gas.

Conflux Core Space 和 eSpace 的区别

Conflux为智能合约提供了两种不同的环境：Core Space和eSpace。 Core Space is optimized for high throughput and low latency, while eSpace is compatible with Ethereum, allowing for easy porting of Ethereum-based contracts.

In Core Space, the gas cost for storage operations is generally lower due to its unique consensus mechanism. eSpace, being Ethereum-compatible, follows a similar gas cost structure to Ethereum, but there are subtle differences due to the underlying Conflux blockchain architecture. Specific gas costs for the SSTORE opcode in eSpace might differ slightly from Ethereum's due to these optimizations.

For instance, while Ethereum charges 20,000 gas for a zero-to-non-zero storage write, eSpace might have slight variations based on the latest protocol updates.

改进的合约实现

Below, we provide an improved contract implementation to manage balance updates efficiently:

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.13;

contract BalanceManagement {
    mapping(address => uint256) public balances;

    // Initialize with non-zero to avoid expensive zero to one write
    constructor() {
        balances[msg.sender] = 1; // Starts with 1 instead of 0
    }

    // Increment balance safely
    function incrementBalance(uint256 amount) external {
        require(amount > 0, "Amount must be positive");
        balances[msg.sender] += amount;
    }

    // Decrement balance, avoiding going to zero
    function decrementBalance(uint256 amount) external {
        require(balances[msg.sender] > amount, "Insufficient funds to decrement");
        balances[msg.sender] -= amount;
        if (balances[msg.sender] == 0) {
            balances[msg.sender] = 1; // Reset to 1 to avoid zero balance
        }
    }
}

Recommendations for Gas Optimization

🌟1. Use Non-Zero Balances: Ensure that token balances do not drop to zero. 如果余额降至零，执行逻辑将其重置为一个小的正值。

🌟2. Optimize Storage Initialization: Start storage variables at a non-zero value to avoid costly initializations and manage subsequent updates carefully to keep modifications within non-zero values.