Linked Questions

19
votes
3answers
4k views

What is the default ordering of transactions during mining?

I know that the yellow paper does not specify how transactions are to be ordered in a block and this is up to the miner to decide. But I am interested in how this is practically handled (I assume not ...
17
votes
2answers
2k views

What happens when a smart contract gets several similar calls in the same block?

What happens when a smart contract gets several similar calls in the same block? Consider for instance this greeter: contract greeter { string name; function setName(string name_) { ...
9
votes
2answers
448 views

Update the same variable in parallel? [duplicate]

I have a global variable foo that I'd like people to be able to increment in a shared fashion. int foo; function addToFoo(int value) public { foo += value } Im concerned that if this function ...
6
votes
1answer
721 views

Can you execute a contract twice in one block? [duplicate]

If you call a contract with two different tx from different account, can they be executed and mined in the same block? If yes how do you guarantee order and concurrency integrity like deadlocks?
5
votes
2answers
207 views

Is it possible to time a transaction such that it is the last in a block?

Is there some method to create a transaction and make sure that it is the last in that block? If not, how close can you get to being last? The reason I ask is that the following page depends on that ...
4
votes
3answers
1k views

Race conditions when calling remote contracts

Below I extracted the logic which calls a remote contract to calculate the amount of tokens to withdraw funds. contact Example { mapping (address => uint256) balances; ERC20 token = ...; // ...
4
votes
1answer
445 views

getStorageAt: What if two transactions in the same block?

I use web3.getStorageAt to access historical information. I can specify a block to see the content of a variable in a given block. But one block can contain several transactions, each modifying this ...
3
votes
2answers
515 views

Can a miner “cheat” my lottery smart contract?

I developed a smart contract that you: 1) Send 1 ether to an address, the contract saves your address 2) After 5 people have sent one ether, the contract chooses one address at random and sends the ...
1
vote
1answer
43 views

Smart Contract GridLock / Stuck Thread

Since Smart Contracts can call multiple contracts, is there a chance that smart contracts enter a gridlock situation?
0
votes
1answer
102 views

How do smart contracts handle race conditions? [duplicate]

Let's say I have deployed a smart contract game that rewards the first user that writes to contract after a point in time T. Naturally, every player will try to be that winner, causing many requests ...
0
votes
1answer
538 views

how blockchain can handle the concurrency? [duplicate]

I read some pages here about concurrency but I didn't give my answer, actually I am new to Bchain, consider this scenario: There is a game contract on the blockchain for 4 Players, so far three ...