Ethereum gas and gaslimit
first, you need to create a "Genesis" JSON configuration file, which describes some parameters of the genesis block. The following is the content of the file:
{
& quot; coinbase": & quot;& quot;,< br />" config": {< br />" homesteadBlock": 5
},
" difficulty": & quot; 0x20000",< br />" extraData": & quot; 0x",< br />" gasLimit": & quot; 0x2FEFD8",< br />" mixhash": & quot;& quot;,< br />" nonce": & quot; 0x0",< br />" parentHash": & quot; 000000000000000000000000",< br />" timestamp": & quot; 0x00",< br />" alloc": {< br />"& quot;:< br />{
" balance":& quot;& quot;
}
}
} 1234567891011213141516171819
the above code into a text file and name it genesis.json
Genesis!:
in order not to conflict with the data of the main chain, it is recommended to establish your own private chain data folder. On my computer, I built an ethdbspace as the Ethereum experimental work area on disk e, and created a privchain folder as the data storage folder of my first private chain
here, in order to facilitate management, I put genesis.json under the ethdbspace folder
open the windows command line
type the following command
geth -- dataDir & quot; E:\ EthDBSpace\ PrivChain" init " E:\ EthDBSpace\ genesis.json" 1
– the dataDir option is used to specify the data directory of our private chain. On my computer, it's E: &; EthDBSpace\ Privchain
init is the genesis command, followed by our Genesis configuration file path
after clicking enter, the execution result is as follows
at this time, genesis is complete
create an account:
in order to do experiments on the private chain, we also need to create our own account on the private chain
windows command line, type
geth -- dataDir & quot; E:\ EthDBSpace\ PrivChain" Console1
we have successfully created the world, so when we enter the client for the second time, we do not need to specify the genesis.json file path again, but directly – dataDir to indicate the private link data path
the console command is used to open the command line of geth
after clicking enter, the client will be initialized for a while. After the command prompt appears, it means that you have entered the geth console
type
personal. Newaccount (& #) in the geth command line; Your Password') 1
the personal.newaccount function is used to create an account, in which the parameter is the account password.
after clicking enter, the account creation address will be listed in green below the command, that is, the public key of the account.
we can check the account balance first, In the geth command line, type:
My = eth. Accounts [0]
eth. Getbalance (my) 12
My = eth. Accounts [0]. The purpose of this sentence is to assign the account address we just created to my variable. This can simplify the subsequent account address input. Among them, eth.accounts records the addresses of all accounts on this machine. Since we created an account for the first time, there is only one account on the computer at present. So here we use eth. Accounts [0] to extract the first account address. The eth.getbalance function is used to obtain the account balance, and the parameters are filled in the account address. The my variable here records the address of the first account
I hope my answer can help you
first, smart contracts are so good that they are not useless
smart contracts. As the name suggests, smart contracts refer to contracts that can be executed automatically by computer code; Ethereum virtual machine is used to execute smart contract; Smart account is the carrier that smart contract can be executed. In other words, smart account, this "account" can be controlled by Ethereum virtual machine. According to what control, according to smart contract
there is no free lunch in the world. The smart contract function is so good that it's not useless. When you trade in Ethereum, you have to pay the miner's handling charge. So what's the handling charge you have to pay on Ethereum system, and what's the relationship between
gas and handling charge
2. What's the matter with Ethereum gas
Ethereum gas is similar to automobile fuel. It needs Ethereum gas to drive smart contract. Gas is an English word, Chinese meaning: gas, gasoline, this thing in daily life, is a consumable. Why does Ethereum proce fuel
what is the meaning of gas in Ethereum? In fact, Ethereum's gas is closely related to transaction costs. Ethereum transaction needs service charge. This gas is the calculation mode of service charge of Ethereum
in the setting of Ethereum, the transaction fee is similar to an encrypted fuel, namely gas, which can drive the movement of smart contracts. When Ethereum executes transactions on the blockchain, the fuel will be graally consumed according to the rules of the characteristics
from this point of view, gas is really the same as its original intention, like automobile fuel. If you want to start a car, you must need fuel
What is the difference between the transaction fees of Ethereum gas and bitcoin In essence, Ethereum is a virtual machine, which is decentralized and controlled by people all over the world, forming a "world-class computing network". When you send a token, execute a contract, transfer Ethereum, or do other things on the block, the computer needs to calculate when processing the transaction, which consumes network resources. In this way, you have to pay the "gas" to get the computer to work for you and the miners to process the transaction for yougenerally, the higher the gas price the sender is willing to pay, the greater the value the miners get from the transaction, and the more likely the miners are to choose the transaction. In this way, miners are free to choose to trade. In order to set the gas price for the sender as a reference, miners can directly put forward the lowest gas price they need to execute the transaction
How to calculate the gas consumption of Ethereumwhen Ethereum virtual machine processes transactions, Virtual Opportunities process one by one according to the operation instructions determined in the transaction, and each operation instruction has a specified gas consumption
Ethereum system stipulates two accounts: one is normal account and the other is smart account
for ordinary transfer transaction, that is to call "normal account", the required gas is fixed 21000
when calling "smart account", because the complexity of smart contract is different, the required gas is also different. The more resources (computation, memory, etc.) used to process transactions, the more gas will be needed. For example, an addition operation will consume 3gas. If more complex operations are performed, the more gas will be consumed
then you may ask a question: when a user's transaction involves a malicious smart contract, the contract is extremely complex, and the execution of the contract will consume unlimited fuel, what should we do? The solution of Ethereum system is: in order to avoid unlimited gas consumption caused by malicious
smart contract, the user needs to set the maximum allowable fuel consumption when sending the transaction, namely
gaslimit. In this way, even if there is a malicious smart contract, the worst case is only within the fuel consumption range specified by gaslimit
What is the relationship between Ethereum gas and transaction feeson Ethereum, the service charge you pay is equal to gasprice times gasused
you can understand gasprice as the unit price of fuel and gasused as how many liters of fuel the car needs
for a car, if you say 20 yuan per liter of gasoline, 10000 liters of gasoline is 200000 yuan. For Ethereum, each
gas is 20 gigabytes (gigabytes is the unit of quantity of Ethereum currency), and 10000 gas is: 20 times 10000 equals 200000 gigabytes, 20000 gigabytes equals 0.0002 Ethereum, that is to say, the transaction procere is 0.0002 Ethereum
the specific exchange value is shown in the following table:
for specific exchange rate query, you can check the following website:
for details https://jin10086.github.io/etherconVerter/
both gas price and ether price are freely regulated by the market, but they are different in that the price of ether fluctuates according to the market situation, while the price of gas is determined by miners, If the price of fuel falls below the miners' minimum requirements, the miners refuse to process the deal. The separation of gas and Ethereum can protect the system from the possible fluctuation with the rapid change of Ethereum price
generally speaking, most miners will choose to give priority to their interests. When dealing with the transaction, they will arrange according to the gas price from high to low, and give priority to those with high gas price. If you are in a hurry to trade, you need to raise the gas price so that the miners can see you earlier; If you are not in a hurry, you just need to set a gas price, which is above the bottom line of gas price set by miners
How is gas obtainedin fact, gas is the ether coin purchased from the miner. The ether coin in the user's own account can purchase gas from the miner, and the Ethereum client will automatically purchase gas with Ethereum according to the specified maximum transaction expenditure limit
Where did gas go in the endfor each transaction, the initiator of the transaction must set the gas limit and gas price. Different operations will proce different gas costs. When the gas is used up, the miner will stop executing, and the gas used will be used as a reward to the miner. This will involve several situations:
the first situation is that if there is a surplus gas, the miner will stop executing, Then the remaining gas will be returned to the transaction initiator or the creator of the smart contract. For example, if I send an Ethereum to Yiyi, the gas limit I set is 50000, and the gas normally consumed is 21000, then the remaining 29000 that has not been consumed will be returned to me
in the second case, if the gas limit I set is too low, or the Ethereum in my account is not enough to pay for my gas consumption, then the transaction will be cancelled e to insufficient gas, and the gas used for calculation will not be returned to my account
in the third case, if the transaction fails, I have to pay the handling charge for the occupied computing resources
How to set a reasonable gas pricebefore each transaction, you can query this website to confirm the gas price to be set: https://ethGasstation.info/ To sum up, in this article, we mainly introce the gas and service charge of Ethereum: gas is equivalent to fuel oil. When you process transactions on Ethereum virtual machine, you will consume computing resources, that is, gas. On Ethereum, the service charge you pay is equal to gasprice multiplied by gasused, that is, the unit price of gas multiplied by the total amount of gas consumed. The complexity of the operation is different, and the cost of gas is also different. When the gas is used up, the miner will stop executing, and the gas used will be used as a reward to the miner. The miner will give priority to the trader with higher gas price
eth0 to awk for processing
where - F & # 39;:|< br />+'
this is a separator defined by awk and then matched with "BCAST & quot;, Take the content of the fourth column
since your command is not universal, you can't output the result here, but you should intercept the broadcast address
& gt; eth.estimateGas({ from:eth.accounts [1], to: eth.accounts[2], value:50000000000000 })
21001
> Eth. Gasprice
2000000000
as above, the account [1] = & gt; The transaction of account [2] needs 21001 gas, and the current gasprice is 2000000000. Let's verify that
unlock account 1, send this transaction, and start mining packaging
gas limit