WIP: Propose the gas system for mutation and query session about db3

[jingchen2222]

Concept of Gas and Fee

Gas

The concept of Gas represents the amount of computational effort required to execute specific operations on the state machine.

Gas is used to track the resource usage of operations during the execution

GasMeter

GasMeter: keeps track of the gas consumed during executions that lead to state transitions. It is reset on every transaction execution.

BlockGasMeter

BlockGasMeter: keeps track of the gas consumed in a block and enforces that the gas does not go over a predefined limit. This limit is defined in the Tendermint consensus parameters and can be changed via governance parameter change proposals.

why we need gas fee

Gas is used to evaluate the estimation effort or resource required to execute transactions, including read, write and computation.

EIP Gas Fee Model

EIP 1599

https://eips.ethereum.org/EIPS/eip-1559

• Basefee
• Capacity
• Miner tip

How to estimate gas for mutation and query

In this section, we are looking into ways to evaluate mutation and query.

https://ethereum.org/en/developers/docs/evm/opcodes/

Mutation gas

Regarding mutation, we are considering proposing a gas formula as shown below:

Mutation_(gas) = kvs_len * COMPUTAION_GAS_PRICE  + data_bytes * STORAGE_GAS_PRICE

Query gas

KVQuert_(gas) = kv_query_count * COMPUTAION_GAS_PRICE

BlockGasMeter

It is necessary to set up a limit on the maximum gas for each block so that we can guarantee every node can finish the execution with the given minimum configuration.

Block Gas Check

• Configurate BlockGasLimit based on the given configuration

• Put block_gas into BlockState
• Verify block_gas < BlockGasLimit inside check_tx

Reference

• https://ethereumprice.org/gas/
• https://eips.ethereum.org/EIPS/eip-1559
• https://docs.ethermint.zone/basics/gas.html
• https://www.youtube.com/watch?v=Yh8cHUB-KoU
• Ethereum gas, gas limit, gas price