65
votes
Accepted
What are the limitations to estimateGas and when would its estimate be considerably wrong?
estimateGas works by pretending the transaction was actually being included in the blockchain, and then returning the exact gas amount that would have been charged if that pretend operation was real. ...
- 22k
31
votes
Accepted
how to estimate gas cost?
Using Truffle and testrpc. It's actually pretty easy to build a development environment and test different use cases.
For the gas estimation, it's mostly based on Web3 native functions:
You can ...
- 7,187
21
votes
Estimate gas price with ethers.js
There is a method called estimateGas in the Contract class. Example for how to use it:
const erc20Abi = [ /* ... */ ];
const address = "TOKEN_ADDRESS_HERE";
const provider = ethers....
- 17.3k
18
votes
How to estimate gas at contract creation/deployment to private ethereum blockchain
Try using .getData().
.getData() returns the encoded parameters of a function in order to send the transaction manually. You can then stick this in web3.eth.estimateGas() (the one on web3.eth, not on ...
- 7,280
18
votes
Accepted
What happens if transaction runs out of gas before transaction completes?
Correct, it rolls back. Except for one thing: it gives the miner all the gas, you don't get that back. That's what keeps attackers from spamming, and it's fair anyway because the miner still had to do ...
- 1,936
18
votes
Accepted
Estimate gas price with ethers.js
Found it!
https://docs.ethers.io/v5/api/providers/provider/#Provider-getGasPrice
Hint: the search functionality on docs.ethers.io isn't great - this method didn't show up by searching for "...
- 576
15
votes
Accepted
How to whitelist up to 50k addresses in a single contract?
Quick Lower Bound
You can put a lower bound on the cost, because each address will include one SSTORE, at the very least. So the cost to hard-code 50k addresses, at 20 kgas each would be more than 1 ...
- 6,361
12
votes
Composition Over Inheritance - Gas Efficiency
We have two approaches:
Inheritance
contract Parent {
string w;
function Set(string _w) public {
w = _w;
}
function Greet(string name) internal view returns(string) {
...
- 1,802
11
votes
how to estimate gas cost?
The answer provided by Greg Jeanmart perfectly explained how to estimate the gas cost for a function. Here I want to point out that the design of your function giveAwayDividend() might be vulnerable ...
- 146
11
votes
Estimate gas price with ethers.js
As of 2022 you should use getFeeData() since getGasPrice() has been deprecated. This accounts for network fee changes introduced in EIP-1559. The creator of Ethers.js talks about this in the above ...
- 251
10
votes
What are the limitations to estimateGas and when would its estimate be considerably wrong?
One limitation I have found, or at least a noteworthy aspect of the eth.estimateGas method, is that it only works as intended if the actual call does not throw an exception.
This may well be a bug in ...
- 101
9
votes
Accepted
Mist Testnet error "it seems this transaction will fail"
You can't send ether to this constructor or it will fail by design. If you want the opposite behavior then you specify the keyword "payable" in the function. It helps prevent errant transactions ...
- 54.8k
9
votes
Correct syntax for estimating gas cost of a function in Web3?
UPDATE:
It is simpler to use contract.methods.methodName.estimateGas with web3 1.0.x:
myContract.methods.SetMessage(_message)
.estimateGas(
{
from: _from,
...
- 2,017
9
votes
Accepted
how to estimate gas limit when using web3.eth.sendSignedTransaction
Include nonce field in estimate gas calculation.
web3.eth.estimateGas({
"from" : walletbase,
"nonce" : value,
"to" : contractAddr,
"data" : data
...
- 206
9
votes
Accepted
Does using a very high gas limit somehow get your transactions executed slower?
In short: It's exactly as you suspect, a higher gas limit means your transaction is less likely to be included by miners.
The reasoning: miners seek to maximize their profit within each block. Calls ...
- 2,816
8
votes
Accepted
Infinite gas estimation from solc for simple function
There are many cases when the gas estimator reports infinite gas. However, it doesn't necessarily mean that there is an infinite loop in your code or that your code is incorrect but just the estimator ...
- 10.9k
8
votes
Getting infinite gas estimates for simple functions
I suspect this is because the cost of those functions is indeed unbounded. Strings can be of any length, so setNewMessage() needs to store an unbounded amount of data, and getMessage() needs to read ...
- 27.9k
8
votes
Accepted
How can I estimate price of data storage?
Currently the only times you pay for storage are when you write it and when you read it back. There is no ongoing cost for storage, although there have been some discussions about whether there should ...
- 16.8k
8
votes
Accepted
Do intermediate memory variables cost gas?
Here is more information about storing data in solidity https://solidity.readthedocs.io/en/latest/introduction-to-smart-contracts.html#storage-memory-and-the-stack
Those variables, which you defined, ...
- 1,802
7
votes
Is it possible to calculate the gas costs of a transaction exactly upfront?
The short answer is: it depends, for some transactions state changes might change the pre calculated gas costs.
It is possible to calculate the gas costs of every transaction given the current state. ...
- 7,586
7
votes
Accepted
Why ether transfer sometimes use more that 21000 gas?
That's because when the normal transaction took place, there was no contract code at this address (it was created here at block 15158470, but the tx is at block 15152542). So all that was paid was the ...
- 7,386
6
votes
Accepted
How do you estimate the gas cost of any arbitrary function in Remix IDE?
If you put the cursor on the name of the function in Remix, on the top right of the screen you will see the required gas.
Hope this helps
- 8,280
5
votes
Accepted
Gas estimation for mapping updating with web3js
With web3 1.0.x and with contract ABI:
const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
estimate();
async function estimate() {
const ...
- 2,017
5
votes
Accepted
Gas, gas price, gas cost
In the transaction object { from:web3.eth.accounts[0], data:tokenCompiled.token.code, gas: 1000000 } the gas property is indeed the maximum to be used for the transaction.
The transaction object can ...
eth♦
- 85.1k
5
votes
Can't estimate gas usage in Mist 0.5.2
The wallet block count always lagged behind the eth.blocknumber as reported by Geth and ethstats. After upgrading to Homestead, this problem disappeared.
- 181
5
votes
Accepted
Understanding "eth_estimateGas" results estimating gas
I'm too lazy to 100% confirm, but I'm pretty sure that in the example you gave, the key difference is that the cheaper transaction was for the full token balance of the sender. This means they ended ...
- 27.9k
5
votes
Accepted
Gas cost tests: Sending a transaction to a new address is more expensive?
Yes this is true. If you read the Ethereum Yellow paper you can see in Appendix H that you have to pay extra gas if you send Ether to a new account.
This is to discourage addresses sending a load of ...
- 1,052
5
votes
Composition Over Inheritance - Gas Efficiency
In a 1-1 comparison Composition is more expensive to deploy, and execute. That said, if you need to deploy many instances, you could use the Library pattern and use composition in that way.
Libraries ...
- 1,357
5
votes
Do intermediate memory variables cost gas?
It depends on the settings used when compiling the Solidity.
https://solidity.readthedocs.io/en/v0.4.25/using-the-compiler.html
As tested by @Aquila, compiling with the optimizer leads to the same ...
eth♦
- 85.1k
5
votes
Can I estimate the total gas limit of several dependent transactions?
You can use this solution to sync the state of public ethereum chains into your local private blockchain in truffle (or embark) and then locally simulate the execution of both transactions in the ...
- 1,820
Only top scored, non community-wiki answers of a minimum length are eligible