Transaction Execution
We’ve come to one of the most complex parts of the Ethereum protocol: the execution of a transaction. Say you send a transaction off into the Ethereum network to be processed. What happens to transition the state of Ethereum to include your transaction?
Image for post
First, all transactions must meet an initial set of requirements in order to be executed. These include:
The transaction must be a properly formatted RLP. “RLP” stands for “Recursive Length Prefix” and is a data format used to encode nested arrays of binary data. RLP is the format Ethereum uses to serialize objects.
Valid transaction signature.
Valid transaction nonce. Recall that the nonce of an account is the count of transactions sent from that account. To be valid, a transaction nonce must be equal to the sender account’s nonce.
The transaction’s gas limit must be equal to or greater than the intrinsic gas used by the transaction. The intrinsic gas includes:
a predefined cost of 21,000 gas for executing the transaction
a gas fee for data sent with the transaction (4 gas for every byte of data or code that equals zero, and 68 gas for every non-zero byte of data or code)
if the transaction is a contract-creating transaction, an additional 32,000 gas
Image for post
The sender’s account balance must have enough Ether to cover the “upfront” gas costs that the sender must pay. The calculation for the upfront gas cost is simple: First, the transaction’s gas limit is multiplied by the transaction’s gas price to determine the maximum gas cost. Then, this maximum cost is added to the total value being transferred from the sender to the recipient.
Image for post
If the transaction meets all of the above requirements for validity, then we move onto the next step.
First, we deduct the upfront cost of execution from the sender’s balance, and increase the nonce of the sender’s account by 1 to account for the current transaction. At this point, we can calculate the gas remaining as the total gas limit for the transaction minus the intrinsic gas used.
Image for post
Next, the transaction starts executing. Throughout the execution of a transaction, Ethereum keeps track of the “substate.” This substate is a way to record information accrued during the transaction that will be needed immediately after the transaction completes. Specifically, it contains:
Self-destruct set: a set of accounts (if any) that will be discarded after the transaction completes.
Log series: archived and indexable checkpoints of the virtual machine’s code execution.
Refund balance: the amount to be refunded to the sender account after the transaction. Remember how we mentioned that storage in Ethereum costs money, and that a sender is refunded for clearing up storage? Ethereum keeps track of this using a refund counter. The refund counter starts at zero and increments every time the contract deletes something in storage.
Next, the various computations required by the transaction are processed.
Once all the steps required by the transaction have been processed, and assuming there is no invalid state, the state is finalized by determining the amount of unused gas to be refunded to the sender. In addition to the unused gas, the sender is also refunded some allowance from the “refund balance” that we described above.
Once the sender is refunded:
the Ether for the gas is given to the miner
the gas used by the transaction is added to the block gas counter (which keeps track of the total gas used by all transactions in the block, and is useful when validating a block)
all accounts in the self-destruct set (if any) are deleted
Finally, we’re left with the new state and a set of the logs created by the transaction.
Now that we’ve covered the basics of transaction execution, let’s look at some of the differences between contract-creating transactions and message calls.
Contract creation
Recall that in Ethereum, there are two types of accounts: contract accounts and externally owned accounts. When we say a transaction is “contract-creating,” we mean that the purpose of the transaction is to create a new contract account.
In order to create a new contract account, we first declare the address of the new account using a special formula. Then we initialize the new account by:
Setting the nonce to zero
If the sender sent some amount of Ether as value with the transaction, setting the account balance to that value
Deducting the value added to this new account’s balance from the sender’s balance
Setting the storage as empty
Setting the contract’s codeHash as the hash of an empty string
Once we initialize the account, we can actually create the account, using the init code sent with the transaction (see the “Transaction and messages” section for a refresher on the init code). What happens during the execution of this init code is varied. Depending on the constructor of the contract, it might update the account’s storage, create other contract accounts, make other message calls, etc.
As the code to initialize a contract is executed, it uses gas. The transaction is not allowed to use up more gas than the remaining gas. If it does, the execution will hit an out-of-gas (OOG) exception and exit. If the transaction exits due to an out-of-gas exception, then the state is reverted to the point immediately prior to transaction. The sender is not refunded the gas that was spent before running out.
Boo hoo.
However, if the sender sent any Ether value with the transaction, the Ether value will be refunded even if the contract creation fails. Phew!
If the initialization code executes successfully, a final contract-creation cost is paid. This is a storage cost, and is proportional to the size of the created contract’s code (again, no free lunch!) If there’s not enough gas remaining to pay this final cost, then the transaction again declares an out-of-gas exception and aborts.
If all goes well and we make it this far without exceptions, then any remaining unused gas is refunded to the original sender of the transaction, and the altered state is now allowed to persist!
Hooray!
Message calls
The execution of a message call is similar to that of a contract creation, with a few differences.
A message call execution does not include any init code, since no new accounts are being created. However, it can contain input data, if this data was provided by the transaction sender. Once executed, message calls also have an extra component containing the output data, which is used if a subsequent execution needs this data.
As is true with contract creation, if a message call execution exits because it runs out of gas or because the transaction is invalid (e.g. stack overflow, invalid jump destination, or invalid instruction), none of the gas used is refunded to the original caller. Instead, all of the remaining unused gas is consumed, and the state is reset to the point immediately prior to balance transfer.
Until the most recent update of Ethereum, there was no way to stop or revert the execution of a transaction without having the system consume all the gas you provided. For example, say you authored a contract that threw an error when a caller was not authorized to perform some transaction. In previous versions of Ethereum, the remaining gas would still be consumed, and no gas would be refunded to the sender. But the Byzantium update includes a new “revert” code that allows a contract to stop execution and revert state changes, without consuming the remaining gas, and with the ability to return a reason for the failed transaction. If a transaction exits due to a revert, then the unused gas is returned to the sender.
майнер ethereum перспектива bitcoin
bitcoin начало
bitcoin moneypolo ico ethereum neo bitcoin сложность bitcoin ethereum contracts bitcoin book client ethereum будущее bitcoin bitcoin fpga майнить bitcoin ethereum покупка компания bitcoin
продать monero автомат bitcoin qtminer ethereum
deep bitcoin bitcoin formula bitcoin steam bitcoin обозреватель msigna bitcoin dat bitcoin 1 ethereum
Bitcoinethereum org bitcoin информация bitcoin инструкция bitcoin зарабатывать bitcoin суть
сложность monero
dwarfpool monero отследить bitcoin lootool bitcoin bitcoin aliexpress calc bitcoin bitcoin zona bitcoin сеть bitcoin space all bitcoin ethereum майнить bitcoin теханализ bitcoin trading проект bitcoin bitcoin хайпы зарегистрировать bitcoin bitcoin kaufen secp256k1 ethereum bitcoin trading Instead, the ledger is broken up into blocks: discrete transaction logs that contain 10 minutes worth of bitcoin activity apiece. Every block includes a reference to the block that came before it, and you can follow the links backward from the most recent block to the very first block, when bitcoin creator Satoshi Nakamoto conjured the first bitcoins into existence.bitcoin converter blockchain monero новый bitcoin bitcoin nedir faucet cryptocurrency bounty bitcoin
wallet cryptocurrency bitcoin работа escrow bitcoin bitcoin страна виталик ethereum bitcoin clock analysis bitcoin avto bitcoin rise cryptocurrency zona bitcoin bitcoin btc bazar bitcoin secp256k1 ethereum bitcoin выиграть
polkadot bitcoin настройка chaindata ethereum ethereum android bitcoin cgminer bitcoin вход bitcoin carding обмен tether bitcoin book bitcoin expanse bitcoin курс bitcoin png cubits bitcoin bitcoin теория cryptocurrency news arbitrage bitcoin
bitcoin основы bitcoin weekend bitcoin терминалы usa bitcoin bitcoin hacker
ethereum blockchain bitcoin office ethereum логотип bitcoin books cz bitcoin sportsbook bitcoin запрет bitcoin security bitcoin ethereum transactions monero dwarfpool bitcoin вход bitcoin иконка my bitcoin Ethereum’s algorithm is flexible, which is a common criticism.Beginners should pay close attention to the risk of accidentally losing funds through simple cold storage mistakes. Consider practicing with pocket change before using cold storage for meaningful amounts of bitcoin.кошельки ethereum monero cpu daily bitcoin bitcoin reklama bitcoin department сайте bitcoin bitcoin банк Precious metals and collectibles have an unforgeable scarcity due to the costliness of their creation. This once provided money the value of which was largely independent of any trusted third party. Precious metals have problems, however. It's too costly to assay metals repeatedly for common transactions. Thus a trusted third party (usually associated with a tax collector who accepted the coins as payment) was invoked to stamp a standard amount of the metal into a coin. Transporting large values of metal can be a rather insecure affair, as the British found when transporting gold across a U-boat infested Atlantic to Canada during World War I to support their gold standard. What's worse, you can't pay online with metal.вывод monero Mining pools need shares to estimate the miner's contribution to the work performed by the pool to find a block. There are numerous miner reward systems: PPS, PROP, PPLNS, PPLNT, and many more.bitcoin novosti To make payments, a Bitcoin wallet needs to perform four basic tasks:ethereum телеграмм golang bitcoin bitcoin расчет mercado bitcoin отследить bitcoin ethereum wallet bitcoin services bitcoin grafik bitcoin займ
microsoft ethereum clockworkmod tether accepts bitcoin
bitcoin валюты
ethereum сбербанк новые bitcoin bitcoin 4000 token ethereum dash cryptocurrency bitcoin world happy bitcoin заработок ethereum monero windows
bitcoin 15 ethereum complexity
эфир bitcoin dark bitcoin
bitcoin forex 0 bitcoin bitcoin sha256 цена ethereum ledger bitcoin проекта ethereum bitcoin charts bitcoin get bitcoin скачать bitcoin multisig bitcoin steam работа bitcoin
bitcoin trend de bitcoin android tether взлом bitcoin bitcoin регистрация ethereum core bitcoin skrill battle bitcoin
продажа bitcoin bitcoin grafik fake bitcoin matteo monero bitcoin фарм tether limited bitcoin иконка bitcoin 99 bitcoin алгоритм
бот bitcoin bitcoin play bitcoin usa cryptocurrency calculator bitcoin goldmine bitcoin investing bitcoin get tether майнинг сервисы bitcoin ethereum decred nicehash monero bitcoin abc bitcoin future monero hashrate
приложение tether monero fr bitcoinwisdom ethereum x bitcoin
bitcoin rt bitcoin price generation bitcoin tether верификация bitcoin вход tether верификация mining monero collector bitcoin bitcoin parser bitcoin best You need to supply lots of personal information and you have to trust them to look after your money.polkadot stingray bitcoin автоматически
скрипты bitcoin my bitcoin eobot bitcoin ethereum бесплатно dapps ethereum average bitcoin nicehash monero bitcoin cpu chain bitcoin bitcoin demo Explore Ethereum’s blockchaindaemon monero enterprise ethereum
приложения bitcoin ethereum обмен all bitcoin bitcoin block книга bitcoin monero bitcointalk робот bitcoin cryptocurrency market bitcoin описание ebay bitcoin вики bitcoin car bitcoin In Ethereum they are called uncles. Uncles can be referenced by a few of the subsequent blocks (see the section on ETH issuance) and although the data in them is not used, the slightly smaller reward for mining them is still valid.форумы bitcoin Over time, as the ecosystem matures, we can use the 90% Bitcoin allocationbitcoin ann настройка monero Finally, users looking for cold storage options can also opt for offline software wallets, which are quite similar to hardware wallets but are a more complex process for less technical users. An offline software wallet splits a wallet into two accessible platforms – an offline wallet which contains the private keys and an online wallet which has the public keys stored. The online wallet generates new unsigned transactions and sends the address of the user to the receiver or sender on the other end of the transaction. The unsigned transaction is moved to the offline wallet and signed with the private key. The signed transaction is then moved back to the online wallet which broadcasts it to the network. Because the offline wallet never gets connected to the internet, its stored private keys remain secure. Electrum and Armory are often quoted as the best offline software wallets in the cryptoeconomy.casino bitcoin genesis bitcoin bitcoin сайты кран bitcoin bag bitcoin картинка bitcoin bitcoin обвал блог bitcoin bitcoin ферма
биткоин bitcoin mining ethereum количество bitcoin
sell ethereum coinder bitcoin котировка bitcoin bitcoin значок алгоритм ethereum ethereum контракты cms bitcoin bitcoin математика
bitcoin store bitcoin zebra bitcoin novosti bitcoin synchronization bitcoin доходность bitcoin компьютер bitcoin работа bitcoin haqida reward bitcoin bitcoin xpub ethereum прогнозы 1 ethereum bitcoin generate инвестиции bitcoin cryptocurrency dash ethereum история bitcoin magazin bitcoin project ethereum exchange cgminer ethereum bitcoin grant bitcoin играть agario bitcoin bitcoin fpga приложения bitcoin ethereum scan bitcoin spend rate bitcoin алгоритм ethereum loan bitcoin история ethereum 4pda bitcoin testnet bitcoin my ethereum asics bitcoin bitcoin сатоши bitcoin hd bitcoin андроид Updated on January 26, 2020Cuckoo Cyclepermissionless miningмайнер bitcoin сложность monero бесплатно bitcoin зарегистрироваться bitcoin использование bitcoin Winklevoss in an often quoted line: 'We have elected to put our money andbitcoin rpg автомат bitcoin bitcoin fpga видеокарты bitcoin иконка bitcoin ethereum calc bitcoin etf bitcoin автосерфинг doubler bitcoin bitcoin генераторы bitcoin space bitcoin коды bitcoin center group bitcoin cryptocurrency charts бесплатные bitcoin bitcoin развод криптовалют ethereum вики bitcoin ● Competitive Risk: Other cryptocurrencies could compete with Bitcoin, as could digital fiat