Questions tagged [blocks]

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

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2answers
3k 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 ...
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0answers
307 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: "...
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1answer
718 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(). ...
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4answers
913 views

Estimation of blocks time generation programmatically

What is the correct way to estimate blocks time generation for chain with Web3?
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1answer
253 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 ?
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1answer
194 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 ...
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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 ...
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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 ...
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0answers
125 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
139 views

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

I want to simulate orphaned block locally, it's possible to do this?
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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 ...
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2answers
3k 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
373 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.
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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 ...
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0answers
484 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 "...
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1answer
11k 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.
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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 ...
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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 ...
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2answers
79 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.
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0answers
182 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. ...
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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 ...
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2answers
981 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?
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2answers
2k 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 ...
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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 ...
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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....
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1answer
122 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
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1answer
126 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 ...
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1answer
158 views

how blockchain-cloud companies like Storj prevent changing files by farmers? [closed]

How does companies like Storj handle the possible situation of farmers who can change the files that they store? Say I upload to the blockchain cloud network the file "cat.jpg". Now a contract added ...
5
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1answer
419 views

What are the mechanisms that use the Ethereum network to decide when a block B is done and we are going to mine block B+1?

I know from the Ethereum Stats that a block is mined on average within 14 secs. But that is only on average. I want to know, step by step if possible, what are he mechanisms to say "okay, this block ...
4
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0answers
75 views

Will forthcoming ability to make transactions private hide gas usage and mining information?

I understand that people are working on allowing for more private transactions on the public Ethereum mainnet. This would involve hiding (at the very least) the from, to, value and probably input ...
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1answer
688 views

How are the blocks traversed?

How are the blocks traversed? Is it using a linked list concept to traverse? If I need to see all block details, will it traverse from the genesis block to the requested block or will it traverse ...
2
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1answer
982 views

Calculate approximative block height at a certain time?

What would be a formula for calculating the block height at a certain point in time, approximative How would I calculate the block height for a date like next Christmas 0h midnight?
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2answers
4k views

What does every field in block means

Can you give a detailed description for every field in Ethereum's block structure? For example: > eth.getBlock(123) { author: "0xbb7b8287f3f0a933474a79eae42cbca977791171", difficulty: ...
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0answers
74 views

Can a contract know about other transactions in the same block as one of its own? [duplicate]

I've read that transactions in the same block that call the same contract will execute in an arbitrary order if sent from different accounts. My question is, for any given transaction that may be ...
2
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2answers
437 views

Why doesn't ethereum have a fast relay network like Bitcoin?

I'm talking about nodes that miners connect to that help relay blocks fast, to reduce hash power wastage and forks: http://bitcoinrelaynetwork.org/ and http://www.falcon-net.org/
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1answer
134 views

logically centralized but physically decentralized contract

Reading https://uport.me/library/pdf/whitepaper.pdf it states : The uPort Registry Contract acts as a logically centralized but physically decentralized registry or lookup table mapping each uPort ...
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1answer
5k views

Is there a way to recover ETH with Account Number and Password Only?

I have 1 ETH in an Ethereum Wallet. I would like to transfer it, but I am unable to get the wallet functions to work due to another issue. (Mist not recognizing my 1 ETH) I know the wallet address and ...
3
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2answers
232 views

Transaction not performed, morden.ether.camp has different transactions than me (Morden)

I'm on morden network. I received Ether and waited roughly one hour, but I have > web3.eth.getBalance("0x3061c735f4e9172a3c66d07fcde6ea560bb3369c") 0 However, the transaction is confirmed: https:...
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1answer
364 views

How many blocks are created at one point of time?

How many blocks are created at one point of time? Can miners create a block? If Yes, then how can we stop the same transaction to be entered in two different block?
3
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1answer
959 views

How does Ethereum avoid inaccurate timestamps in blocks?

A contract can reference the currently being mined contract's timestamp. This means that changing the timestamp of an in-progress to be mined block requires executing all contracts referencing that ...
8
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1answer
2k views

What action would actually lead to an invalid block and what happens to the valid transactions in that block

I'm trying to figure out how an invalid block would come into existence and what happens (technically) to valid transactions in the invalid block. From what I understand, invalid transactions (like ...
21
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3answers
5k views

Why does ethereum creates a new block,without even a single transaction? [duplicate]

I'm running a private Ethereum blockchain. When I set one of the nodes to mine, that node continuously creates blocks, even if there are no transactions inside of it. What is the purpose of this?
2
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1answer
724 views

Can I call contract function (balanceOf) based on block number?

I want to check the DAO balance address in the specify time(block number) Is it possible to specify the block number when calling a contract function in web3. var contract = web3.eth.contract(abi)....
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2answers
2k views

Blocks are not being downloaded [duplicate]

After the attacks the clients are shit. At the moment, I am unable to download any blocks, except if I delete all the chaindata and it starts again. I have less than 6k blocks left to download and I ...
4
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1answer
6k views

How to speed up transaction confirmation time?

I recently ran some tests on one of my testnet nodes and found out that my average transaction takes between 30 seconds to 2 minutes to confirm, despite the block times being at around 15 seconds. I ...
4
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1answer
144 views

Should uncles factor into average network block time and difficulty calculations?

It's unclear to me if uncles should factor into averages like block time and difficulty. The fact that they are associated with a parent block and have a timestamp and difficulty, leads me to believe ...
4
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2answers
850 views

what is the logic behind rewarding 5 ETH for mining a block?

Is it in someway related to the transaction cost charged by ethereum for each transaction ?
11
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3answers
28k views

Storing document/file in blockchain [duplicate]

I am planning to do a POC on blockchain for uploading and verifying documents. I was wondering if I can store a complete document in blockchain. After some research on net most of the example, I found ...
19
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1answer
6k views

Are gas limit in transaction and block gas limit different?

What does gas limit mean? Are there two meanings of gas limit? gas limit in a transaction block gas limit