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Questions tagged [blocks]

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

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1answer
13 views

How do Miner choose transactions for a block?

i am wondering how a Miner chooses the transactions, he want to mine inside a block. For example, a Miner has got the Transactions T1 and T2 at the moment he starts a new mining work. This Miner is ...
2
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1answer
20 views

Can the block number be set back in ganache?

I know about tools like ganache-time-traveler that let you advance the block number. But is it possible to go back to a lower value?
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1answer
14 views

In ethereum network how data structured and is every data stored, is public?

Let's say, 3 companies are using ethereum network. Company A Company B Company C Company A put some data, block01 and block02. So ethereum network looks like, Genesis Block -> block01 -> block02 ...
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2answers
24 views

Does a transaction that consumes the block gas limit take an entire block by itself?

Does a transaction that requires the entire block gas limit to be executed (currently ~8M) take the entire block by itself? And if that's true, will that transaction take longer to get confirmed than ...
0
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1answer
13 views

Can I rely on certain oracle to know the precise and reliable timestamp?

I am learning the security impact of smart contract on system properties like block.timestamp and block.number. I understood that block.timestamp can be controlled by the miner to certain degree and ...
1
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1answer
22 views

“The bigger the block size, the greater the computational power needed to mine a block” Does this make sense?

I was going through one of the papers and the authors in the paper mentioned this statement. I am not able to find the correlation as such. I do understand that Larger blocks may propagate slower ...
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0answers
13 views

Mining pool assign blocks

I've been researching mining pools to figure out how they assign work to miners. I understand that pool would get a job from the blockchain they only has a header, dag, difficulity, probably block ...
2
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2answers
180 views

Avoid using “now”

I am using "now" to save the block timestamp details. But there is a warning to avoid its usage. If we need to avoid it what is the best alternative to it.
1
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1answer
29 views

Are transactions to EOA included in a block guaranteed to be successful?

Regardless of the source of the transaction (externally owned address / smart contract) and the data included within the transaction, if the destination is an EOA and the transaction was included in a ...
2
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1answer
34 views

Are transactions with zero data included within a block guaranteed to be successful?

I know there are transaction receipts to verify that a transaction included in a block was executed successfully and funds were actually transferred. But can receipt verification be skipped if I'm ...
0
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1answer
10 views

How to get blocks from which an adress has taken coins&

I need to undeerstand how to find out from which blocks come coins that are currently stored at somee adress.Will be pleased to hear any suggestions.
2
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2answers
84 views

What is the difference between account nonce and block nonce?

Block and accounts both use a value called "nonce" but they seem to represent something very different. For account I understand that the nonce is an integer quantity indicating the number of ...
4
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1answer
45 views

Timestamp in Ethereum

I have a smart contract where the user inputs temperature readings, I'd like to add a time stamp to relate those reading with a current time of submission. I understand that in Ethereum we only have ...
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1answer
35 views

How to calculate average gas price of several blocks?

I want to calculate average gas price of several blocks (in Gwei), however I don't see how a field on blocks for gasPrice. Do I have to calculate it by grabbing the gasPrice of each transaction in ...
0
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1answer
23 views

Is there any library to estimate timestamp of future block?

I am in need of a library that estimates a date or some sort of timestamp when fed with a future block number (on mainnet or any major testnet). For instance, https://etherscan.io/block/countdown/...
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0answers
17 views

Parity synced at not existing block 4839212

I have problem with parity, cant get synchronization in archive mode to end, anything, changing arguments, max-, min-, snapshot-peers, parity verisions do not help. I have blockchain in archive mode ...
0
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0answers
27 views

Is latest block returned by eth.getBlockNumber fully processed

According to web3 docs, web3.eth.getBlockNumber returns the number of the most recent block. My question is simple. Is it safe to assume block's transactions and events are already in the node or ...
1
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1answer
27 views

Fetching block template from node

The most famous opensource pool uses eth_getBlockByNumber method with parameter "pending" to get block template and generate jobs from it. But now, in parity, I found that this parameter is deprecated ...
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0answers
45 views

What is the m_seal fields in the block header used for?

Can someone please explain what these extra fields in the block header are and what are they for? Edit: Oh, I just understood myself -- mixHash and nonse are stored here. But why is this data ...
1
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3answers
173 views

Increase block number on Ganache

How can we increase block.number on Ganache for testing purpose ? If not possible do you know an alternative like passing X fake transactions to artificially increase block.number. Or if we have to ...
3
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1answer
198 views

When is a new block created?

I am currently reading an interesting book about solidity, and I'm reading about block creation. This gives a good overview: The book mentions that the maximum size of a block is determined by the ...
1
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1answer
18 views

Can I get the timestamp for a transaction added to mempool?

Can I get the time stamp on when a transaction was added to the mempool and when it was successfully added to a block? Is there an API to do this?
6
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1answer
1k views

My friend sent me a screenshot of a transaction hash, but when I search for it I find divergent data. What happened?

This is the transaction hash: 0x90e923ee01d9dfeb95ee176819eeec67d247fc6cb009c8cdc4d8ae1939e5ecc6 And this is the screenshot my friend sent me: If you check the hash in Etherscan, some informations ...
1
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1answer
47 views

Is there a smart contract recording all block hashes on in the ethereum blockchain, as they come in?

I'm wondering whether anyone has already made a contract and corresponding off-chain service which, once every 30 minutes or so, triggers the contract to record all the block hashes which have gone by ...
2
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1answer
32 views

Known cases of miners withholding blocks when used as randomness?

There are some applications that use the blockhash as a source of randomness, often with a payout similar to a lottery. I've heard of attacks where it would be more profitable for a miner to withhold ...
1
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1answer
263 views

How to get the value of the transaction?

I am using web3.py but I need help to know the value of the transaction sent. I know that the information is stored in the input but how do I parse the string. I know nothing about ABI. Here is the ...
0
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1answer
13 views

changing source of random number based on reward?

Would this be an acceptable way to produce a random number dependent on the reward? Say if the reward is high enough to entice a miner to manipulate the block then the contract will utilize oraclize. ...
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2answers
267 views

Modify number of confirmations

By default there are 24 confirmations but I am running a testnet with just 3 miners and I would like to change this number bucause it makes not sense to have 24. I have been checking ...
0
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0answers
12 views

How to read the data from block?

In my smart contract, I am inserting plain text message. I can also update the message. After updating, if I want to see the previous message, is it possible? Can I see all the data in etherscan.io?...
1
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0answers
40 views

How to mine a Empty Block or reject transaction?

How Can a miner can mine a empty block,reject honest transactions to be added into block ; does it mean we could tweak the miner client , if yes could someone tell how it is done and what are the ...
1
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1answer
148 views

How can i implement deadlines in smartContract?

Suppose I am running a gallery and ask participants to submit there paintings before a specific date. After passing that date participant should not be able to submit their entry. How can I implement ...
1
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1answer
21 views

Make sure I don't jump any blocks

I'm making a simple program to track transactions in and out of an address, I have a function that gets the latest block and then I run it consecutively. When I run the function sometimes the block ...
2
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0answers
65 views

How to read block propagation delay from ethstats.net?

I am wondering what is the average (or mdeian) time it takes to propagate a block in the Ethereum blockchain? I found ethstats.net provides a cummlative graph for block block propagation but do not ...
1
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1answer
22 views

How to change all the ethereum blocks from C drive to D drive — question about the answer

I'm new here and have no idea if this is the right way to respond. So I duplicated the question a have a question about: I've done the things written in the answer on the original question and I ...
0
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1answer
28 views

Is there multiple chains of block in ethereum network?

Since blockchain is a chain of blocks, In ethereum, 1. is there only one chain of blocks 2. are there multiple chains of blocks.
1
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0answers
46 views

What actually a block contains, is the data inside it a virtual or physical entity?

My understanding of a block in blockchain is that it is a data structure that contains information like Block Size, Block Header, Transaction Counter and then Transactions. Deeper in the Block Header ...
1
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1answer
249 views

How State variable are stored and updated?

The Smart contract and the state variables are stored in the blockchain, let us say during deployment of a smart contract the state variable and smart contracts are stored in the block 1, and in ...
1
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1answer
60 views

Looking for an Ethereum sniffer

I have been looking for a sniffer similar to Bitcoin P2P Network Sniffer (https://github.com/sebicas/bitcoin-sniffer) which could allow me to connect to Ethereum nodes and listen to blocks and ...
1
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1answer
37 views

Getting the last synced block is 0

I am trying to get last synced block but it always 0. So I have run geth --syncmode fast -cache 4096 --rpc Here is a logs INFO [12-19|09:47:50.058] Imported new state entries count=...
1
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2answers
79 views

Who generates the mathematical problem for miners?

In POW miners solve an problem for successfully mining a block, who provide the question to the miners ?, does all miners work on same problem ?, and how the miners verify the answer ?, if the problem ...
0
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1answer
54 views

how to get the last incoming transaction before date

I need to get the incoming transaction before the date currently i use https://web3api.io/api/v1/addresses/0xaD4b04Df17f2d35F81771Fa124dBD94E33587F4c/transactions?to=...
1
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0answers
58 views

Get blocks between dates

I am trying to get the block between dates . for that i use web3.js . per day average block is 6172 so if i need previous day block i use below code fromBlock: (await web3.eth.getBlockNumber()) - ...
0
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2answers
100 views

can only change header's extra data to mine a new block? [closed]

Fix 'nonce' and 'mixDigest', only change 'extra' to mine a new block.
1
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1answer
36 views

How will Proof of Stake affect blockhash generation

When (and if) Ethereum switches to proof of stake, how will the hash of blocks (most likely) be set?
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0answers
44 views

Ethereum Blocksci parser tool

I need a blocksci parser for ethereum. I am using https://github.com/citp/BlockSci for bitcoin . Is any similar blocksci parsing tool for ethereum?.
1
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2answers
51 views

0 txn in mined block [duplicate]

How is it possible for a block to be mined with 0 txn? https://etherscan.io/block/6739171 That's an easy way to get 3 ETH block rewards.
1
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1answer
21 views

Is state read from the current or previous block for external function calls?

Given that a computer must execute in a sequence, I assume the VM is also doing so before deciding the final block state. Let's say my contract calls an external function from another contract that ...
8
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2answers
222 views

Possible error in white paper validation algorithm?

If we take the block validation algorithm described in the white paper (Section Blockchain and Mining), it states at point 6: Let TX be the block's transaction list, with n transactions. For all i ...
5
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1answer
30 views

Will block numbers be sequential on a sharded blockchain

When Ethereum shards (assuming it does) will the block numbers across the multiple shards be unique? I doubt it (I don't think the shards can have sequential block numbers and be independent of the ...
1
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1answer
31 views

Does a non-miner node validate both single transactions and an entire block?

My understanding is that an originating node broadcasts a transaction to its neighbours, who all validate the transaction to ensure (a) the signature is valid and (b) the state change is valid, before ...