Intermediate

 

Transaction Fees

Welcome to our tutorial on Klaytn transaction fees. In the world of blockchain, transaction fees are a necessary component of maintaining the network and incentivizing node operators to validate and process transactions. In Klaytn, transaction fees are a key aspect of how the network functions and are used to pay for the computational resources required to validate and execute transactions. In this tutorial, we will explore the concept of Klaytn transaction fees in detail, including how they are calculated, how they are used, and their impact on the network. Whether you are a developer, researcher, or simply a blockchain enthusiast, this tutorial will provide valuable insights into the inner workings of Klaytn transaction fees and how they play a role in the functioning of the Klaytn network.

In Klaytn, transaction fees are a necessary component of maintaining the network and incentivizing node operators to validate and process transactions.

Transaction fees in Klaytn are calculated based on the amount of computational resources required to validate and execute a transaction. Each operation performed by a smart contract, such as a function call or storage read/write, costs a certain amount of gas. The total cost of a transaction is the sum of the gas costs of all the operations performed by the smart contract. The gas price is determined by the market, and it fluctuates based on the demand for computational resources on the network.

Transaction fees are paid in KLAY, the native token of the Klaytn network. The sender of a transaction must include enough KLAY to cover the transaction fees when sending a transaction. The transaction fees are then distributed to the node operators who validate and process the transaction, as a reward for their work.

Transaction fees serve several important functions in the Klaytn network:

• They incentivize node operators to validate and process transactions, as they earn a reward for their work in the form of transaction fees.

• They help to prevent spamming and denial of service attacks by making it expensive for malicious actors to flood the network with unnecessary transactions.

• They help to ensure that the network has sufficient resources to process all the transactions by adjusting the gas price based on the demand for computational resources.

The impact of transaction fees on the network is mainly focused on the cost of performing transactions for the users, as well as the distribution of rewards for the node operators. High transaction fees can make it more expensive for users to perform transactions, which can discourage the use of the network. On the other hand, low transaction fees can make it less profitable for node operators to validate and process transactions, which can lead to a shortage of computational resources on the network.

In summary, Klaytn transaction fees are a key aspect of how the network functions, they are used to pay for the computational resources required to validate and execute transactions and they serve several important functions such as incentivizing node operators, preventing spamming and denial of service attacks and ensuring network resources.

The transaction fee for the current Klaytn virtual machine (KLVM) is calculated as follows:

(Transaction Fee) := (Gas Used) * (Base Fee)

• The Gas Used is computed by KLVM based on the gas cost of the opcode and the intrinsic gas cost.

• Base Fee is the actual gas price used for the transaction. It has the same meaning as the Effective Gas Price.

This calculated transaction fee is subtracted from the sender’s or fee payer’s account balance, depending on the transaction.

Gas and Base Fee Overview

Gas

Every action that changes the state of the blockchain requires gas. When a node processes a user’s transaction, such as sending KLAY, using KIP-7 tokens, or executing a contract, the user has to pay for the computation and storage usage. The payment amount is decided by the amount of gas required.

Gas is a measuring unit representing how much calculation is needed to process the user’s transaction.

Dynamic Gas Fee Mechanism

Since the Klaytn v1.9.0 hard fork, a dynamic gas fee mechanism has replaced the existing fixed fee policy. Dynamic gas fee policy provides a stable service to users by preventing network abuse and storage overuse. The gas fee changes according to the network situation. Seven parameters affect the base fee(gas fee):

1. PREVIOUS_BASE_FEE: Base fee of the previous block

2. GAS_USED_FOR_THE_PREVIOUS_BLOCK: Gas is used to process all transactions of the previous block

3. GAS_TARGET: The gas amount that determines the increase or decrease of the base fee (30 million at the moment

4. MAX_BLOCK_GAS_USED_FOR_BASE_FEE: Implicit block gas limit to enforce the max basefee change rate (60 million at the moment)

5. BASE_FEE_DELTA_REDUCING_DENOMINATOR: The value to set the maximum base fee change to 5% per block (20 at the moment, can be changed later by governance)

6. UPPER_BOUND_BASE_FEE: The maximum value for the base fee (750 ston at the moment, can be changed later by governance)

7. LOWER_BOUND_BASE_FEE: The minimum value for the base fee (25 ston at the moment, can be changed later by governance)

Base Fee

The basic idea of this algorithm is that the base fee would go up if the gas used exceeds the base gas and vice versa. It is closely related to the number of transactions in the network and the gas used in the process. There is an upper and lower limit for the base fee to prevent the fee from increasing or decreasing indefinitely. There is also a cap for the gas and an adjustment value for the fluctuation to prevent abrupt changes in the base fee. The values can be changed by governance.

(BASE_FEE_CHANGE_RATE) = (GAS_USED_FOR_THE_PREVIOUS_BLOCK – GAS_TARGET)

(ADJUSTED_BASE_FEE_CHANGE_RATE) = (BASE_FEE_CHANGE_RATE) / (GAS_TARGET) / (BASE_FEE_DELTA_REDUCING_DENOMINATOR)

(BASE_FEE_CHANGE_RANGE) = (PREVIOUS_BASE_FEE) * (ADJUSTED_BASE_FEE_CHANGE_RATE)

(BASE_FEE) = (PREVIOUS_BASE_FEE) + (BASE_FEE_CHANGE_RANGE)

The base fee is calculated for every block; there could be changes every second. Transactions from a single block use the same base fee to calculate transaction fees. Only transactions with a gas price higher than the block base fee can be included in the block. Half of the transaction fee for each block is burned (BURN_RATIO = 0.5, cannot be changed by governance).

NOTE: An important feature that sets Klaytn apart from Ethereum’s EIP-1559 is that it does not have tips. Klaytn follows the First Come, First Served(FCFS) principle for its transactions.

Transaction Replacement

Klaytn currently does not provide a way to replace a transaction using the unit price but may support different methods for transaction replacement in the future. Note that in Ethereum, a transaction with a given nonce can be replaced by a new one with a higher gas price.

Klaytn’s Gas table

Basically, Klaytn is keeping compatibility with Ethereum. So Klaytn’s gas table is pretty similar to that of Ethereum. But there are some features unique to Klaytn that require several new constants.

Common Fee

Precompiled Contracts

Precompiled contracts are special kinds of contracts that usually perform complex cryptographic computations and are initiated by other contracts.

The total gas of those items which has XXXBaseGas and XXXPerWordGas (e.g. Sha256BaseGas, Sha256PerWordGas) are calculated as

TotalGas = XXXBaseGas + (number of words * XXXPerWordGas)

ValidateSenderGas have to be paid per signature basis.

TotalGas = number of signatures * ValidateSenderGas

Blake2f gas cost is calculated based on the below formula. input is the input of the blake2f call.

Gas = uint64(binary.BigEndian.Uint32(input[0:4]))

Account-related Gas Table

Gas for payload data is calculated below

GasPayload = number_of_bytes * TxDataGas

Gas Formula for Transaction Types

KeyValidationGas is defined as below based on the key type,

KeyCreationGas is defined below based on the key type,

With this, you complete this workshop successfully!!