[Ethereum] How to Specify Gas Limit and Value in wei or gwei

gas-limit

Dear Anyone Who Can Help Me,

This is my first time posting and asking for help, I'm in the midst of Deploying and Running the Transactions in Remix IDE (as per the picture).

I'm stuck at the Gas Limit (as I don't know how much to put)

The same goes for Value in wei or gwei.

As I did try to enter the Gas Limit and Values, I got this error message below:

"Gas estimation failed-
Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending?
gas required exceeds allowance (10000000) or always failing transaction"

Since on the left side, you can see my first deploy smart contract, what is your suggestion to put in Gas Limit and Value in wei or gwei?

Fyi, I'm running Injected Web3 via MetaMask.

The Code:

pragma solidity >=0.4.22 <0.6.0;

contract SWLCoin {
  // declare variables
  address owner;
  string name;
  string symbol;
  uint256 totalSWLCoins;
}

Please advice, many thanks.

Best Answer

Gas Limit (maximum number of gas units required for the transaction to execute):

For this contract, I believe that you won't need more than 1 million gas units. You can put 2 million, I guess there's not much harm in that except for making your transaction take longer to execute. But you cannot put more than the block limit, which is typically around 8 million, depending on what network you're deploying to (mainnet, ropsten, your own private network, etc).

Value (amount of wei-ether passed within the transaction to the contract):

Since you don't have a payable fallback function in the contract, you cannot put anything other than 0, because the transaction will fail otherwise (in fact, that's probably the reason for your error).

Related Solutions

[Ethereum] How Geth and Parity knows the global gas limit

The block gasLimit is in each block. Example:

eth.getBlock(1500000)

{
  difficulty: 34982465665323,
  extraData: "0xd783010305844765746887676f312e352e31856c696e7578",
  gasLimit: 4712388,
  ...
}

[Ethereum] Are gas limit in transaction and block gas limit different

Yes. Each transaction has a gas limit. For example, there could be 5 unmined transactions where each has a gas limit of 10, 20, 30, 40, 50. The block gas limit determines how many transactions can fit in a block. For example, if the block gas limit is 100, then the first four transactions can fit in the block. Miners decide which transactions to include in a block. A different miner could try including the last 2 transactions in the block (50+40), and they only have space to include the first transaction (10).

Every person who creates a transaction can decide what their transaction's gas limit is: but it would not make sense for them to specify something higher than the block gas limit, so Geth and other clients would prevent them from setting too high. It is a gas limit because it is the maximum amount of gas the person creating the transaction is willing to use: they do not pay for any extra gas that is not used. But if they set the limit too low, their transaction can run out of gas and they pay for all of it to the miner.

With the block gas limit, miners are the ones who decide. The bigger it is the more they can get from transaction fees, but the more bandwidth and computing they would have to do. Miners cannot change the block gas limit too much within one block: they can only change it by a factor of 1/1024.

The transaction gas limit is the gas property in a transactionObject. The block gas limit is a parameter in the genesis file created (it is client dependent and typically means the minimum block gas limit: a block with a gas limit smaller than it will not be accepted by the nodes on that blockchain).

Best Answer

Related Solutions

[Ethereum] How Geth and Parity knows the global gas limit

[Ethereum] Are gas limit in transaction and block gas limit different

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