Homework on Stale Blocks

Blockchain and Bitcoin 101
#1909

Waiting does not prevent stale blocks. These discrepancies will occur though they are rare (on bitcoin less than once a year). The reason we wait is to make sure our tx is not part of a stale block :slight_smile:

#1910

  1. A new miner from the network will chose one and that will be the chain to run on.

  2. If a minerā€™s block isnā€™t picked up quick enough in the network, that blockchain gets dropped and goes back to the mempool.

  3. When no one continues to mine on that chain.

  4. Common best practices to maintain hisotry of the blockchain.

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#1911

Thank you for the correction @Alko89. Noted! :grinning:

It will only become stale blocks if the network drop the blocks. Right? Iā€™m just confused. Who will decide what chain is the longest chain? Is it the miner or the network? Can you at least share the process of deciding? I would really appreciate if you can answer it. Thanks man!

#1912
  1. They each consider their own version of the blockchain to be the truth until the next block is mined. Then the first block to have a subsequent block mined using their latest hash ā€œwinsā€, and the block from the other miner is dropped.
  2. A stale block is a block that was dropped as in number 1 above.
  3. Stale blocks occur if there is two versions of the truth. The one that is the first to get mined on top of stays, and the other is considered stale.
  4. In case your transaction becomes stale and added back into the mempool.
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#1913

1.the network will choose the longest block or the one who has the longest proof of work, and after that,the other one will be dropped from the network, thatā€™s what we called stale blocks.
2.A block that is rejected from the network because of shorter proof of work or blocks.
3.Stale blocks occur when there is two miners solve the block at the same time from the network
4.to make sure that it will not get dropped by the network.
4.

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#1914

  1. The network will have a temporary scenario of 2 versions of truth until the next block comes along and connect with either block from the 2 miners. The long chain of blocks will be dropped resulting in a situation of a stale block. All transactions from the stale block will be returned to the mempool pending transaction confirmation from other miners.

  2. A block that was dropped/removed from the blockchain.

  3. A stale block is the completed block that was dropped while competing to connect to the next new block.

  4. It is important because it means that all 6 conformations are completed on the transactions and now the transactions are 100% immutable.

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#1915
  1. each block that has been mined and confirmed go on the blockchain. But the block with the longer blockchain will keep while the other block falls off is removed and put back into the mempool. Any other blocks that were built off of that block will also be removed.
  2. A stale block is the block that was confirmed and put on the blockchain but itā€™s blockchain is shorter so it is removed. There canā€™t be two versions of the truth on bitcoin blockchain.
  3. stale blocks occur when two miners guess the nonce of a hash at the same time and both are accepted to the blockchain. But only one can remain (the longer blockchain).
  4. itā€™s important to wait for 6 confirmations after sending or receiving a transaction because of the chance of a stale block occurring.
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#1916

  1. 2 block begin to propagate. Miners may accept one or the other, this creates 2 chains, in which eventually everyone will find out about. The chain that has a block added to sooner will be the longer chain, hence the network will accept that chain as the real blockchain.

  2. A block that was dropped because it was part of a shorter chain.

  3. Stale blocks occur when miners identify that there is a shorter chain.

  4. Because it is possible for there to be 2 competing chains that eventually will be reduced to one. You do not want to be counting on something that may not become the truth.

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#1917

Understood thank you

#1918
  1. What happens in the bitcoin network when two miners solve a block at the same time?

A. The blockchain showing the most proof of work (more difficulty with a lower target) will be selected.

  1. What is a stale block?

A. A stale block is a block that has been confirmed by the network but then dropped in favor of a competing block due to less proof of work. All UTXOā€™s are returned to the mempool.

  1. How do stale blocks occur?

A. When miners are competing to have their block added to the blockchain and a different block is chosen over theirs by being selected to form the next block in the chain, their block is dropped and becomes a stale block.

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

A. It is important to give each new block time to propagate and move through the network before it is either solidified as part of the ongoing blockchain or dropped a different block.

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#1919
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Both blocks will be appended into two separate chains until there is one chain that grows the longest between the two parallel chains.
  2. What is a stale block?
    The shorter chain from the fork described above will then gets returned to the mempool. This is the stale block. It used to be a block that was once appended into the blockchain but then gets dropped.
  3. How do stale blocks occur?
    Stale blocks occur because the blockchain is not appended further through this block and it doesnā€™t get enough confirmations / block height to verify its place in the blockchain. Basically happens after two miners mine a valid block each almost simultaneously.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    This allows the information to be propagated through the nodes to have the truth verified mathematically.
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#1920

Both chains continue to get mined by different parts of the network. It is only when a chain gets more PoW done than the other it gets dropped and the longest chain gets adopted. :slight_smile:

It is a good practice to wait in case your transaction becomes part of a stale block.

#1921

At the moment the fork happens it happens on different parts of the network, so each sides donā€™t even know the chain is forked (this is because of physical distances between the nodes in the network), some will receive one block and some the other block.
So miners once they receive a new block start mining on the block they received it is only once they receive a block with higher block number (and hence higher PoW). The miners will drop the block they are working on and start mining on the new block they received and so the fork is considered solved. :slight_smile:

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#1922
  1. They will propagate their block in the network and time will tell if they will be accepted. Typically if the block is still included and accepted for 6 more blocks, it will be part of the shared version of truth.
  2. It is a totally valid block that has been refused by the network in competition with another valid block, and the tx sent back to the mempool of unconfirmed tx.
  3. When two blocks are created at the same time, i.e two miners solve the puzzle at the same time. The two versions of truth is ā€˜bornā€™ at the same time i.e two different valid blocks are created.
  4. To make sure that the tx will be included in a block that will be part of the blockchain and not be a stale block.
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#1923
  1. When two miners solve a block at the same time it cause the block chain to split in two and the two block chains are valid.
  2. A block that gets dropped.
  3. When there are two valid block chains eventually one will win. The one with the longest chain and the other blocks get dropped and sent back to the mempool.
  4. It is important to wait for more than one block to be confirmed because you want to make sure your block is not in the chain that gets dropped.
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#1924

What happens in the bitcoin network when two miners solve a block at the same time?
They will be picked up by nodes, but the block by a 3rd miner will determine which it will follow based on whatever miner has the more difficult and longer blocks. Then the other miner chain will reject and becomes a stale block

What is a stale block?
Block that was dropped and no longer has a value on the blockchain.

How do stale blocks occur?
Occurs when 2 miners solve a block at the same time, but the next miner that picks up the next block picks up the longer/more difficult block to continueā€¦ Leaving the block of the miner that was not picked left stale.
Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
To avoid the idea of two miners solving at the same nonce and there can ideally be 2 versions of the block so that you donā€™t end up with a stale block.

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#1925

  1. When 2 miners solve a block at the same time, the chain splits for a while in two: their new Blockchain gets propagated around to the next nodes in their area. On both new chain, miners will keep on adding until 6 next blocks and confirmation of only one of these two simultaneously solved and added blocks. One remains on chain, the second gets removed.

  2. & 3. The following blocks appended to a valid block that get removed because of adoption of another block where chain splitted are the stale blocks. From split, all following blocks will be removed and transactions go back to the mempool.

  3. We wait before sending a transaction that its containing block not only is valid, but also is confirmed and so chosen to pursue the blockchain through the whole network.

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#1926

when this happens the network accepts the Longest blocks with the most difficulty [ most POW]
and lowest target because the longer the block the harder to alter.

Stale blocks are valid blocks that were on the block at one time but got dropped because there are blocks with different and longer versions of the blockchain without that block on it.

Stale blocks occur when more than one miner come up with a nonce on the blockchain at the same time, when the network accepts the block with the longest block and lowest target, it then returns the block back as a valid rejection to the mempool,
these blocks are called Stale blocks

It is important to wait for 6 confirmations to avoid your block not being accepted by the blockchain with that said the LONGER the block the HIGHER your chance of being added and not sent back to the mempool resulting in a stale block.

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#1927

1.These two blocks will be added to other nodes and then the longest chain wins while another block will be refused, and all transactiond are returned to mempool.
2.Stale or orphaned block is a block dropped from the blockchain because there was other block in a longer chain
3.They occur when 2 miners mine a block at the same time, and then on of them is dropped
4.There is a possibility that your block might be dropped from blockchain ans become a staleblock

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#1928

  1. The block in which more blocks are built, will be the one that finally wins.

  2. It is a duplicated block that is dropped from the blockchain because there is another block that was created at the same time, but with a larger chain.

  3. They occur because two miners resolve the puzzle at the same time, but finally only one can stay in the blockchain.

  4. This is a way to avoid the problem that each node will contain different blocks.

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