Questions tagged [blocks]

This tag is for questions dealing with the structure of blocks.

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3
votes
1answer
213 views

API to enumerate the blocks from a specific day

I'm trying to find an API that lists all the blocks from a specific day, as we can do with bitcoin: https://blockchain.info/pt/blocks/1515628800000?format=json I've searched etherscan.io and ...
2
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1answer
4k views

What is the size of the Ethereum blockchain for full and light nodes? [duplicate]

What is the size of the Ethereum blockchain for full and light nodes? What is the size of the Ethereum blockchain, and where can I look it up? Furthermore, does the size depend on the particular ...
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0answers
243 views

How to verify whether a certain transaction is mined by the newest block programmatically?

What I thought I should do I implemented this functionality with Bitcoin Core through zmq support. Keep "my transactions" through zmq's rawtx topic. When received zmq's rawblock, decode the raw ...
2
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0answers
285 views

Solidity - check PoW difficulty

If given block data and a difficulty number, is it possible to verify that the header produced is at or above the provided difficulty from within Solidity? For example, suppose I have the following ...
1
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1answer
67 views

Get the time a block was mined

My front-end displays the timestamps of various contract actions that have taken place. However, the current block.timestamp it's using isn't very accurate, because the miner has some leeway in ...
0
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1answer
50 views

Which is going to be the very last block of 2017?

I know that the last moment of the year depends in which time zone you are. But lets assume that we want the very last moment, so let's consider the last time zone (+12), I believe is Fiji or New ...
0
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2answers
63 views

Who are the miners?

In blockchain there are some miners who calculate hash and get reward but my question is who are the miners or how can I be a miner (assume). If there are then I can be connected to a miner? I am ...
1
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3answers
367 views

How to architect scalable ethereum blockchain network?

I have set up the private ethereum block by doing the following steps. 1- Initialised same genesis.json on 2 systems. 2- Started geth console by using same network id. 3- Added these two systems (...
0
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3answers
544 views

How to get address balance after particular block was issued

How to get address balance if you know the block number? In solidity you can call address.balance, but without specifying particular block. Is there a way to do this in solidity or only py/js?
2
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1answer
609 views

How is the block gas limit dynamically adjusted?

What mechanism lies behind adjusting the block gas limit dynamically? Is it the miner that mined the most recent block who decides whether to adjust the gas limit or not? How much can the block gas ...
3
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1answer
736 views

Block header format

Does anyone understand what each element of a block header represents? I have an example block header represented here: [ cd7bd64fba4cc782fe5474d3640882afece5887180591e72f80ce6916cf73526, ...
4
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1answer
1k views

When are “pending” transactions dropped from the blockchain?

When are transactions dropped from the blockchain? Suppose I broadcast a transaction to the blockchain, then it is a pending transaction waiting to be mined. But when are pending transactions ...
23
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3answers
11k views

Is it possible to cancel a transaction?

Is it possible to cancel a transaction broadcast to the blockchain? Suppose I broadcast a transaction and want to cancel it before it has been mined. Is this possible? This could be useful on ...
2
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1answer
555 views

Max data storage per block

I'm wondering how much data a smart contract can store per block. Ex: The gas limit is currently ~6,700,000, and it costs 20,000 gas to store 32-byte word. So the EVM can store a maximum of 335 bytes ...
0
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1answer
79 views

How to transfer tokens after 6 blocks? [duplicate]

I have created a smart contract that expects to receive ether via Etherum Wallet desktop app or MyEtherWallet site. The contract then sends equivalent amount of tokens to the ether sender on the same ...
3
votes
1answer
818 views

Meaning of Imported New Chain Segment

This is not a troubleshooting question, I'm not having problems with geth or the blockchain sync, but I'm curious about the meaning of a text that appears at the end: Imported new chain segment. I ...
4
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2answers
1k views

What is the timestamp of a confirmed transaction based on?

Specifically, if we look at any transaction on the Ethereum blockchain, is the TimeStamp based on when the transaction is generated (like when you click generate transaction on MEW), or is it based on ...
0
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2answers
604 views

How to get a list of ALL block hashes yet?

I'm looking for a way/link/service to get a list of ALL (~4400000) block hashes yet. Any idea how to get that? Thanks
1
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1answer
926 views

How to get the full miner reward

Okay so let's say I'm looking to get block 1000000 miner reward: { difficulty: 12549332509227, extraData: "0xd783010303844765746887676f312e352e31856c696e7578", gasLimit: 3141592, gasUsed: ...
1
vote
1answer
489 views

How reliable is it to use Block number to calculate Time in Smart contract?

I have seen contracts use block numbers to manage when the crowdsale should start and stop. How reliable is this? I understand the average time in ethereum is 17secs between blocks, but can this be ...
1
vote
1answer
373 views

Is it possible for transaction not to be processed with low Gwei? [duplicate]

Is it possible for transactions not to be processed with low Gwei? Or will always be processed just will take some time? Assume I do 1000s of transactions with 1 Gwei, can I rest assured that all ...
2
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1answer
72 views

Does increasing gas price decrease number of txs in a block?

Assume I figure out a way to pay 5+ ETH in gas costs for a transaction. Will this make my transaction the only transaction in the block because the block reward is currently 5 eth?
0
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2answers
2k views

How to estimate block number at future date/time?

I am creating a smart contract that will allow actions to be taken during a specific time period. Ideally, I would like to let users know in advance the start block/end block that the contract will ...
1
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0answers
261 views

Local ethereum node contain two different blocks but with same height

I am using geth node and found 2 different block with same number eth.getBlock("0x162ae4b189f77ed65d0be270aa8dea08d4e7dcd70432a7d1fd4e6b0fb1b301d6") { difficulty: 1001546728, extraData: "...
0
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1answer
692 views

Transaction, block and mining

I'm looking for a detailed explanation (video would be the best) how and when transaction is being mined on Ethereum network (in theory), since the moment it's created with web3.eth.sendTransaction(). ...
0
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4answers
780 views

Estimation of blocks time generation programmatically

What is the correct way to estimate blocks time generation for chain with Web3?
1
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1answer
239 views

Uncles and its parameters

Is there possible that current block do not have uncles? As we know that Main block contain the contract information , What does uncles holds ?
1
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1answer
180 views

Where can I find the block that contains most recent state of contract's memory/storage?

I am considering trying to use or implementing some form of light Ethereum node that only needs access the most recent version of data stored in smart contract storage on the blockchain and trying to ...
0
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1answer
1k views

Ethereum Block Structure - Roots and Tries Concept

Trying to reinforce my understanding, so hoping you guys may help me out. From reading the Ethereum wiki, I believe part of an Ethereum block header consist of the following: stateRoot ...
0
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1answer
1k views

What are the differences (and relationship) between the steps used to (1) validate a transaction and (2) confirm a block?

On the Ethereum blockchain, what is the difference (and relationship between) (1) the process used to validate a transaction and (2) the process used to confirm a block? It seems that these processes ...
2
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0answers
121 views

Ethereum RPC equivalent of bitcoind's listsinceblock

Is it something have go-ethereum or parity similar as listsinceblock? Because iterate step by step from chosen block number/hash to actual eth.blockNumber will be very expensive operation.
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0answers
123 views

How to simulate orphaned/forked block locally? [duplicate]

I want to simulate orphaned block locally, it's possible to do this?
6
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2answers
2k views

What happens to transactions in orphaned/forked blocks?

From my investigation and reading a lot about this, it seems like the transaction is just removed and the ether returns back to some address. With Bitcoin, orphaned blocks are initially accepted by ...
5
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2answers
2k views

What is the mean transaction size and average number of transactions per block on the Ethereum blockchain?

I found an April 7, 2017 post on Bitcoin Stack Exchange saying that Over roughly the past two months, the mean transaction size was about 506 bytes, and the average count of transactions per ...
6
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1answer
305 views

How to detect if block was forked?

It's is possible to track by API, if block was forked/orphaned? Will be glad to see some example.
6
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3answers
3k views

Block gas limit exceeded when compiling contract Solidity browser

Using Solidity Browser ( https://ethereum.github.io/browser-solidity/ ) to mine a contract on testnet with injected web3 and metamask account, throws this error: callback contain no result Gas ...
2
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0answers
481 views

Syncing block chain

I was syncing the blockchain using something like geth --fast --cache=2000 -jitvm. It reached about block #3819000, and then it did something odd. It stopped saying "Imported x reciepts" or "...
14
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1answer
10k views

What are Ethereum transaction receipts and what are they used for?

I've seen mention in a few places that blocks store transaction receipts, but I haven't really seen an explanation of what they are and why they exist.
0
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1answer
1k views

How to track the transactions in private ethereum blockchain

I am bit confused by the value of "root" I get in transaction receipt according to my understanding root is the value which points to previous block in block chian, but when I try to track that ...
0
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0answers
42 views

What gets mined in a private test network? [duplicate]

I followed the instructions in this answer to get a private testnet. When I start mining in dev/private network using miner.start() what exactly is being mined? Since I am the only node in the ...
3
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2answers
73 views

Reading most recent blocks without syncing chain

I would like to be able to read the newly created blocks and list of transactions it included within, without storing the chain on my desktop. Can that be done? Thanks.
2
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0answers
176 views

In a private blockchain network, can we delete the first N blocks and reassign the N+1th block as the genesis block?

I am aware of the data loss caused by deleting the first N blocks. But I am curious to know whether such a task is possible or not. If so, how to practically implement it? ( I am using go-ethereum. ...
5
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2answers
1k views

Transaction logged at geth node, but unable to locate Transaction entry on Ropsten

When sending new transactions one at a time (meaning separated by 1 or several minutes in time) they are correctly broadcasted and mined. But when sending several of them one after another (spearated ...
1
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2answers
869 views

Web3JS: Call Smart Contract but where is the data returned?

I am trying to call a Smart contract that is supposed to return an address. I have tried the contract in Remix and It all works fine. I am know trying to execute the same contract using We3JS. To do ...
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2answers
3k views

how can i get details of transactions from any block number without using event?

Without using event i want to fetch all the details of how many transaction with transaction id are contained in any specific block by just putting block number?
8
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2answers
1k views

If all nodes execute smart contracts, why do only block creators get the gas fee?

I have a question regarding smart contract execution. It is my understanding that when a user requests a smart contract, miners will execute the smart contract, and bundle its output in a block ...
2
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0answers
1k views

How to get raw binary data from ethereum blockchain?

I want to get ethereum blocks as binary data and parse them manually to get raw ethereum transactions. Are there any good manuals how to do it? UPDATE: how ethereum genesis block (at height #0) looks ...
5
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1answer
2k views

Web3 retrieving latest transactions [duplicate]

Is there any way in the Web3 Javascript API to retrieve the latest, let's say five, transactions that were done on the blockchain? The only option I can think of, is by using web3.eth.getBlock(web3....
1
vote
1answer
113 views

Need for Merkle path of a transaction to verify its membership in a particular block

I have read about the Merkle path of a transaction (path in Block B's Merkle tree from the txn T to the Merkle root) being needed to verify that txn T is included in block B, and I understand that. ...
2
votes
1answer
121 views

When 2 blocks or more are distributed at the same time, but the longest one delayed

I have a problem understanding the concept of handling two or more blocks that distributed at the same time (in the blockchain network). As far as I understood, When I get 2 or more blocks at the ...