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.
tether программа ethereum solidity the ethereum lottery bitcoin bitcoin maps tether yota продам ethereum ethereum токены ethereum exchange
half bitcoin
metatrader bitcoin
ethereum описание bitcoin 1000 monero dwarfpool bitcoin capital bank cryptocurrency ethereum russia bitcoin super
bitcoin автоматически bitcoin daemon заработок ethereum
bitcoin utopia bitcoin machine bitcoin knots ethereum gas bitcoin nvidia cryptocurrency bitcoin sec bitcoin bitcoin окупаемость bitcoin криптовалюта dark bitcoin bitcoin com алгоритм bitcoin ethereum телеграмм bitcoin автомат polkadot блог заработка bitcoin продать bitcoin alien bitcoin cryptonator ethereum кости bitcoin bitcoin conveyor и bitcoin key bitcoin monero кран криптовалюта tether bitcoin conference bitcoin up casino bitcoin windows bitcoin валюта tether bitcoin деньги pos bitcoin bitcoin окупаемость Subunitsbitcoin сложность Be careful with online servicesMining is the process of securing each block to the existing blockchain using mining software. Once a block is secured, new units of cryptocurrency get released. Miners can inject these units directly back into the market.алгоритм monero
кредит bitcoin forbes bitcoin
монет bitcoin ethereum plasma polkadot блог goldsday bitcoin You don‘t need to understand the details about SHA 256. It‘s only important you know that it can be the basis of a cryptologic puzzle the miners compete to solve. After finding a solution, a miner can build a block and add it to the blockchain. As an incentive, he has the right to add a so-called coinbase transaction that gives him a specific number of Bitcoins. This is the only way to create valid Bitcoins.bitcoin проект mt4 bitcoin bitcoin airbit сервера bitcoin ethereum io портал bitcoin bitcoin mine
bitcoin hype bitcoin location bitcoin добыть bitcoin instaforex bitcoin tm
ethereum addresses
bitcoin today
ethereum pow bitcoin symbol bitcoin список bitcoin token bitcoin приват24
monero pools tether верификация p2pool bitcoin ethereum homestead bitcoin telegram программа ethereum
bitfenix bitcoin bitcoin китай сигналы bitcoin bitcoin бесплатные airbitclub bitcoin форум bitcoin 6000 bitcoin bitcoin server free monero weather bitcoin bitcoin php bitcoin hesaplama bitcoin виджет tether tools bitcoin обменять wifi tether bitcoin блок блоки bitcoin bitcoin коды
monero майнить client ethereum статистика ethereum бесплатно bitcoin bitcoin de production cryptocurrency сервисы bitcoin bitcoin биржи картинки bitcoin bitcoin cap wallet cryptocurrency bitcoin зарегистрировать airbit bitcoin up bitcoin
metal bitcoin bitcoin nvidia сложность monero 4 bitcoin get bitcoin trezor ethereum биржа ethereum monero майнить инструкция bitcoin майнер bitcoin ethereum игра bitcoin converter apple bitcoin работа bitcoin bitcoin луна collector bitcoin
исходники bitcoin bitcoin rpc запросы bitcoin cryptonight monero конвертер ethereum monero криптовалюта hit bitcoin bazar bitcoin майн bitcoin asic ethereum комиссия bitcoin best bitcoin ethereum faucet xronos cryptocurrency
coffee bitcoin 777 bitcoin
bitcoin paper bitcoin config обмен tether bitcoin вложить шахты bitcoin компания bitcoin roboforex bitcoin
адрес ethereum
монета ethereum форки bitcoin bitcoin address Supply-chain managementbitcoin ledger bitcoin значок rpg bitcoin bitcoin суть cryptocurrency dash bitcoin авито bitcoin заработок bitcoin count
сервера bitcoin
bitcoin plugin bitcoin cards bitcoin адреса master bitcoin ethereum wikipedia bitcoin cnbc bitcoin bubble
технология bitcoin bitcoin community The bank stopped George from double spending which is a kind of fraud. Banks spend millions of dollars to stop double spending from happening. What is cryptocurrency doing about double spending and how do cryptocurrencies verify transactions? Remember, they don’t have stuff as the bank does!bitfenix bitcoin
bitcoin инвестирование bitcoin выиграть майнер monero ethereum chaindata ethereum charts
cc bitcoin bitcoin скрипт lamborghini bitcoin yandex bitcoin sgminer monero tokens ethereum bitcoin майнинга bitcoin cli bitcoin цены график ethereum bitcoin venezuela bitcoin ios калькулятор ethereum bitcoin монеты bitcoin atm redex bitcoin bitcoin get bitcoin заработать bitcoin сервисы bitcoin eobot bitcoin rotator jaxx bitcoin How the effects manifest in the real economy is very complicated, but it does not take any sophistication to recognize the general direction of the end game or its foundational flaws. More dollars result in each dollar becoming worth less, and the value of any good naturally trends toward its cost to produce. The marginal cost for the Fed to produce a dollar is zero. With all the bailouts from both the Fed and Congress, whether to individuals or companies, someone is paying for everything. It is axiomatic that printing money (or creating digital dollars) does nothing to generate economic activity; it only shifts the balance of powers as to who allocates the money and prices risk. It strips power from the people and centralizes it to the government. It also fundamentally impairs the economy’s ability to function as it distorts prices everywhere. But most importantly, it puts the stability of the underlying currency at risk, which is the cost that everyone collectively pays. The Fed may be able to create dollars for free and the Treasury may be able to borrow at near-zero interest rates as a direct result, but there is still no such thing as a free lunch. Someone still has to do the work, and all printing money does is shift who has the dollars to coordinate and price that work. bitcoin sweeper bitcoin гарант bitcoin реклама
tether обзор ethereum заработок tether usd bitcoin abc ethereum котировки bitcoin lite bitcoin 99 bitcoin выиграть bitcoin конец
bitcoin flapper ethereum web3 bitcoin обменники ethereum падает bitcoin utopia forum ethereum
simplewallet monero
invest bitcoin криптовалюта monero яндекс bitcoin bitcoin надежность btc ethereum ava bitcoin c bitcoin казино ethereum algorithm ethereum hashrate bitcoin alliance bitcoin bitcoin оборот
cryptocurrency top ethereum хешрейт buy tether check bitcoin обменять ethereum трейдинг bitcoin bitcoin рбк
кран monero bitcoin xl wifi tether кошелька bitcoin claim bitcoin
mt5 bitcoin
ethereum coins bitcoin pools
криптовалюта tether airbit bitcoin bitcoin auto
create bitcoin How much LTC can I buy?сборщик bitcoin xbt bitcoin tether app monero pro bitcoin обмена bitcoin динамика bitcoin hype secp256k1 ethereum connect bitcoin bitcoin token bitcoin system конвертер ethereum bitcoin майнить ethereum frontier
bitcoin stock ставки bitcoin bitcoin cran ethereum mine bitcoin convert alliance bitcoin monero майнить bitcoin valet сайте bitcoin location bitcoin bitcoin рухнул moneybox bitcoin metal bitcoin multiplier bitcoin bitcoin зарабатывать elysium bitcoin bitcoin баланс bitcoin nachrichten bitcoin school
основатель ethereum
cryptonator ethereum air bitcoin mt5 bitcoin дешевеет bitcoin proxy bitcoin bitcoin buying ethereum валюта bitcoin получить bitcoin зарабатывать Mobile wallets are similar to online wallets except that they are built only for mobile phone use and accessibility. These wallets have a user-friendly interface that helps you do transactions easily. Mycelium is the best available mobile wallet.On the surface, the reason we seek money is simple: money lets us buy things. The utility of a new car, or the entertainment of an Xbox, or the taste of a nice steak dinner is apparent, and since we want those things, we seek money.пулы ethereum fpga ethereum uk bitcoin
ethereum заработать half bitcoin рулетка bitcoin bitcoin автор bitcoin synchronization bitcoin click de bitcoin
bitcoin map cryptocurrency это bank cryptocurrency 999 bitcoin
обменник bitcoin bitcoin registration 4pda tether bitcoin установка bitcoin видеокарты
genesis bitcoin Cryptocurrencies like Bitcoin and Ethereum have significant advantages over traditional fiat currencies. To have a better understanding of cryptocurrencies, you should know how blockchain wallets work. The fourth lesson of the blockchain tutorial gives you a deeper understanding of the concept of blockchain wallet. It starts with a section on how blockchain wallets address traditional banking systems' challenges, what blockchain wallet is, and how it works.Early Bitcoin client versions allowed users to use their CPUs to mine. The advent of GPU mining made CPU mining financially unwise as the hashrate of the network grew to such a degree that the amount of bitcoins produced by CPU mining became lower than the cost of power to operate a CPU. The option was therefore removed from the core Bitcoin client's user interface.ethereum mining bitcoin мавроди
bitcoin telegram gold cryptocurrency bitcoin me цена ethereum bitcoin биткоин keystore ethereum secp256k1 ethereum bitcoin analytics donate bitcoin bitcoin vizit ethereum miner основатель ethereum greenaddress bitcoin roll bitcoin simple bitcoin bitcoin onecoin
bitcoin кранов casper ethereum вики bitcoin создатель ethereum bitcoin сеть
bitcoin email bitcoin investing magic bitcoin bitcoin direct magic bitcoin alpha bitcoin bitcoin gold purchase bitcoin bitcoin word dwarfpool monero elysium bitcoin bitcoin перспективы картинки bitcoin lealana bitcoin клиент ethereum bitcoin китай куплю ethereum новости ethereum monero wallet обменять bitcoin space bitcoin trinity bitcoin mac bitcoin investment bitcoin bitcoin cache
boom bitcoin bitcoin asic space bitcoin 60 bitcoin bitcoin rate ethereum wikipedia взлом bitcoin bitcoin hyip live bitcoin валюта tether
monaco cryptocurrency bitcoin source
кликер bitcoin клиент ethereum bitcoin goldmine ethereum калькулятор bitcoin land взлом bitcoin wordpress bitcoin space bitcoin
forbes bitcoin bitcoin nodes приложения bitcoin unconfirmed bitcoin steam bitcoin bitcoin автор bitcoin обменник
bitcoin king ethereum эфириум bitcoin click платформа ethereum валюта monero cnbc bitcoin polkadot faucet cryptocurrency bitcoin хабрахабр bitcoin datadir
habrahabr bitcoin ethereum price parity ethereum стратегия bitcoin bitcoin market secp256k1 ethereum china cryptocurrency bitcoin автоматически торговать bitcoin bitcoin easy график bitcoin
миксер bitcoin swarm ethereum multiply bitcoin bitcoin buying футболка bitcoin bitcoin account bitcoin настройка конвертер bitcoin ethereum casper bitcoin kurs сборщик bitcoin bitcoin транзакция bitcoin gold
bitcoin torrent bitcoin habrahabr ethereum btc блоки bitcoin bitcoin таблица кран bitcoin bitcoin blockstream joker bitcoin bonus bitcoin mine ethereum
ethereum buy bitcoin описание statistics bitcoin зебра bitcoin bitcoin sberbank magic bitcoin
форк bitcoin компиляция bitcoin nxt cryptocurrency обменник tether bitcoin motherboard bitcoin investing group bitcoin bitcoin lottery
joker bitcoin bitcoin analytics новые bitcoin купить bitcoin bitcoin описание
ethereum blockchain россия bitcoin download bitcoin truffle ethereum ethereum майнеры bitcoin описание bitcoin solo
ethereum вики free ethereum bitcoin автоматически bitcoin alpari bitcoin cc bitcoin mempool Cryptographic signaturesbitcoin png bitcoin cnbc monero spelunker bitcoinwisdom ethereum rus bitcoin 6000 bitcoin cryptonator ethereum clicker bitcoin серфинг bitcoin bitcoin check bitcoin life forecast bitcoin анонимность bitcoin bitcoin вход cc bitcoin claymore ethereum casino bitcoin ethereum видеокарты boxbit bitcoin ethereum сайт bitcoin machine magic bitcoin bitcoin safe bitcoin metal habrahabr bitcoin
bitcoin дешевеет monero windows monero xmr bitcoin рублей пузырь bitcoin bitcoin продам block ethereum
программа bitcoin купить bitcoin bitcoin blockstream bitcoin farm price bitcoin get bitcoin ethereum coin collector bitcoin hashrate bitcoin эфир ethereum explorer ethereum 22 bitcoin бот bitcoin bitcoin alert opencart bitcoin free monero register bitcoin bitcoin download bitcoin analysis