Homework on Stale Blocks

Blockchain and Bitcoin 101
#1969

It doesn’t has to reach 6 confirmations. It’s just that the more confirmations (new blocks mined on top) the more certainty you have that the transactions init are imutatable and on the blockchain forever. Because after each new block (confirmation) you require more proof of work to reorg the blockchain with a different longer chain.

When 2 miners mine a block at the same blockheight, you basically fork the blockchain where each blockchain has a different last block. Then it depends on wich blockchain the next miner mines a new block on. Wich makes 1 version a longer chain than the other. The rules are that the longest chain wins. So that block on the shortest chain will become a stale block, and all transactions that aren’t already included in the winning blockchain will go back to the mempool.

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#1970

[quote=“ivan, post:1, topic:8434, full:true”]

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    There would be two version of the blockchain which would eventually lead to a stale block.

  2. What is a stale block?
    A stale is a valid block that was on the blockchain for some time but was dropped because there was another version of the truth, a blockchain that was the longest with more PoW.

  3. How do stale blocks occur?
    Stale blocks occur when a valid block is dropped from the blockchain. This means that there were two competing blocks in the blockchain but one blockchain eventually got longer than the other.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    It is important because it prevents your block from being dropped as a stale block. Good practice is that you wait for at least six blocks after your block.

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#1971
  1. There are two holders of the truth in the POW of the network.
  2. A block that got dropped and placed in the mempool .
  3. Occur when the network decides to run on one of the parallell running blockchains that are true, making it longer based on previous block difficulty. That’s when the stale blocks (shorter version) are dropped.
  4. To be sure a valid block won’t get dropped later. (It’s wise to wait for 6 block confirmations.)
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#1972

Stale blocks will occur (although they are very rare) and eventually get resolved. The reason for the user sending or receiving a tx to wait is so that your tx doesn’t get dropped back to the mempool and potentially double spent. :slight_smile:

#1973

Thank you, new in the space and still learning.

#1974

No worries, we are all here to learn more! :smiley:

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#1975

  1. Both are valid and it is typically sent to the closer nodes. Whichever block the next miner decides to follow is added to the network.

  2. A stale block is a block that was added to the network but is removed because a newer version does not use the block.

  3. Stale blocks occur when two blocks are mined and released at the same time.

  4. It is important to wait because then you can be sure the transaction will go through and not go back to the mempool.

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#1976
  • What happens in the bitcoin network when two miners solve a block at the same time? Both blocks get added to blockchain on nodes closer to them therefore splitting blockchain. As other blocks get added depending on propagation factors one block will retain position in blockchain, all that during the 10 min.
  • What is a stale block? When a block has been added to blockchain but gets dropped due to another block that belongs to a bigger chain.
  • How do stale blocks occur? When miners successfule solve puzzle same time time, but due to nature or data propagating on blockchain the block on the longer blockchain remains and othe block is dropped and all transactions return to mempool.
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? Confirms blocks position on blockchain as the latest verified truth.
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#1977

  1. The longest block will win in the end.

  2. Stale block is a the shortest version of the blockchain where to chains were solved at the same time.

  3. When two blocks are mined at the same time, and the longest chain wins the shorter chain becomes an stale block.

  4. It is important to avoid creating a lot of stale blocks.

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#1978

1.) In the bitcoin network when two blocks are solved at the same time, one or the other will be added on to depending on which one the other nodes thinks is more logical. The longest block continues or wins and the transaction data of the stale or orphaned block is added back into the mempool.

2.) A stale block is simply a block that was at one time added to the block chain but was then dropped for another version of the block.

3.) One way that a stale block can occur is when the block doesn’t have time to be accepted into the blockchain before another is created.

4.) A general rule of thumb is to wait for six transactions to occur before yours is confirmed. This gives a higher likelihood of the transaction being confirmed and subsequently added to the blockchain.

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#1979

When two miners solve a block at the same time, there are then two competing versions of the blockchain. It isn’t until one of the two blockchains gets another confirmed block that the other blockchain is dropped (longest chain in terms of Proof of Work is the “true” or real blockchain).

A stale block is a block that gets dropped from the blockchain as a result of competing with another valid block, which receives another valid block after it first.

Stale blocks occur when a block gets dropped from the blockchain as a result of competing with another valid block, which receives another valid block after it first.

It’s important to wait for more than one block to be confirmed when sending or receiving a transaction since stale blocks can happen and the transaction your block was in can get dropped by the network.

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#1980

Homework - Stale Blocks

  1. What happens in the bitcoin network when two miners solve a block at the same time?

The block with the with the longest chain will survive and the other block will be dropped and these transactions in this block will go back to the mempool

  1. What is a stale block?

Is a block that is dropped because it did not belong to the longest chains of blocks

  1. How do stale blocks occur?

They will occur when they don’t belong to the longest chain and they will be dropped because the other chain will be considered as the true chain.

  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

Because several miners are still competing against each other to be part of the longest chain and there is still a possibility that the block can be dropped which means at least 6 confirmations are needed to know the transaction is going through.

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#1981

You can’t do anything about stale blocks, every now and then they will occur. Thy is it important to wait for the stale blocks to get resolved from the perspective of the user that is trying to send or receive a tx? :slight_smile:

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#1982

1.If two miners solve a block at the same time the one with longest blockchain win. And the another block will be dropped from the chain and transactions returns to the mempool.
2.A stale block is a block that was in the blockchain but then dropped from the chain because its chain was not the longest chain.
3. A stale block is occur when two miners solve a block at the same time in different places and the propagating of the new block to all nodes wasn’t fast enough that means the nodes get the new block of the miner nearby but at the end it is selected the one with the longest chain.
4. To be sure you have to at least wait for 6 confirmations because there is a lot of miners and there is a competitions and since the one is the longest chain is always selected it is good to wait for at least 6 blocks confirmations.

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#1983
  1. The 2 miners respective blocks compete with each other in order to become the longest chain of blocks. The block the next miner picks will branch off to become the next new block chain and the mining resumes with the block that was dropped, stale block, gets put into the mempool.
  2. A stale block is a block that was dropped from the main blockchain.
  3. A stale block occurs when 2 miners compete and the new miner creates a new blockchain and new block cycle continues
  4. 10 minutes or 6 block verfications or what ever comes first just in case a stale block occurs in that time period.
#1984

1. What happens in the bitcoin network when two miners solve a block at the same time?
A fork occurs, where two miner nodes have two different valid versions of the blockchain.
Nodes closest to each miner adopt their blockchain version. The miners wait for new blocks to be added to their version of the blockchain (confirmations). The version with the longest chain stays and the other gets dropped.

2. What is a stale block?
A stale block is a block that was dropped and not chosen by the network because it wasn’t the longest chain. All the transactions in that block are returned to the mempool.

3. How do stale blocks occur?
When their miners didn’t compute the nonce of that block fast enough and/or the new block wasn’t propagated fast enough to other nodes in the network. They are eventually dropped by the network by not having the longest chain/confirmed blocks after it.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Because the block might potentially become stale if there is another block that was solved at the same time. The best practice is to wait for 6 confirmation blocks to determine that your block is chosen by network as the official version of truth.

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#1985
  1. There is for a brief time two valid blockchains
  2. It’s a block that was dropped from the blockchain
  3. When miners start rejecting them because they aren’t part of the longest chain
  4. So you make sure any inconsistency has been sorted out
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#1986
  1. The blockchain temporarily has two halves, a fork, before one block on the chain is chosen to be built upon.
    2&3
    The most proof of work joins the blockchain and the rejected miners block with incomplete transactions goes back to the mempool. Stale block are the blocks that were dropped from the blockchain because there is another version of the blockchain that is longer.
  2. Your transaction may not be based on the correct version of the blockchain if a fork occurs and so you can check transaction is not done on a stale block which will be rejected. Information needs to travel physically to secure the blockchain because of network decentralisation.
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#1987
  1. What happens in the bitcoin network when two miners solve a block at the same time? the longest blockchain will win and the shortest will be dropped from the blockchain and transactions sent back to the mempool.
  2. What is a stale block? Blocks that are dropped from the blockchain
  3. How do stale blocks occur? When two miners mine a block at the same time, who ever has the longest chain will be accepted and the shortest chain will be dropped from the chainline then called stale blocks or orphaned.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? Waiting for 6 confirmations would confirm that your block is still used and not dropped from the blockchain.
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#1988

Mining difficulty ensures that approximately each block gets mined statistically approximately every 10 minutes. So 6 confirmations takes approximately 1 hour. Then you can be 99.99% sure that your transaction will be imutatably recorded on the bitcoin blockchain forever

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