Homework on Stale Blocks

Blockchain and Bitcoin 101
#582

  1. When two miners solve a block at the same time, two different versions of the chain get propagated through the nodes. Eventually one will get dropped and any transactions not in the other block will return to the mempool.

  2. A stale block is one which was dropped from the blockchain.

  3. Stale blocks occur because the network will favour the longest version of the blockchain, so if a miner has added a new block onto one version of the chain, the nodes will accept it over a shorter version and the stale block is dropped.

  4. It is important to wait for confirmations because there is a small chance that the block with the transaction could be dropped, the transaction returned to the mempool and then have to wait to be included in another block. Once 6 blocks have been added to the chain since your transaction, it is safe to assume that there will not be any changes.

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#583
  1. The blockchain forks and the 2 new blocks propagate, then, when the next block is attached to the chain to either one of the 2 new blocks, the chain with the most amount of PoW becomes the chain.
  2. The rejected block is a stale block and its information goes back to the Mempool
  3. It occurs when the miners with the information of the other block are faster to mine
  4. It is important to wait because if a fork ocurs then the transaction will go back to the Mempool.
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#584

  1. When 2 miners solve a block at same time, the network will temporarily fork into 2 blockchains until the next blocks choose which chain to add to. Then the shortest (by difficulty level) will be disregarded (orphaned) however all the transactions in those disregarded blocks returned to the Mempool of the main system.

  2. Stale block is a valid block that was created at exactly same time as another but one had to be dropped which makes that dropped block “Stale” or “Orphaned”

  3. Stale block occurs when 2 miners solve a block at the very same time! However, there can only be one chosen as valid, eventually

  4. It is important to wait for confirmation of more than 1 block (sometimes commonly up to 6 blocks) in case the block with your transaction becomes invalid (Stale).

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#585

  1. They are both added to the blockchain so two “true versions” of the blockchain in the network co-exists while waiting for the next miner to choose which chain to continue on

  2. They are dropped blocks that were dropped due to another and longer version of the blockchain

  3. If the next block gets added to the other chain in the network which also have cracked the algorithm, the blocks from the shorter chain will be dropped and sent back to the mempool

  4. Because it needs to be propagated, completely received and confirmed by the network and that it isn’t dropped from the chain

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#586

It doesn’t necessarily needs to wait for a certain amount of time. The longest blockchain wins. No matter the time. It mostly depends on wich blockchain the next miner is mining on further.

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#587

It doesn’t need to have 6 confirmations to add this block. Waiting for more confirmations for a transaction gives you more security that the transaction will stay on the blockchain. After 6 confirmations the likelihood that your transaction will drop is almost zero. The common rule is the longest blockchain wins in case of more valid blockchains exists. When 2 miners mine a block at the same time, it mostly depends on wich blockchain the next miner will mine on top. (wich creates a longer chain)

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#588

thanks! also forgot that the block are not really eliminated, just returned back to the mempool for other to collect latter :slight_smile:

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#589

1 the 2 blocks a conected with the latest confirmed block (you get 2 strings)

2 a block that was correctly mined and confirmed in first but was not accepted through the whole network

3 when 2 blocks a mined at the same time there a 2 strings confirmed in a part of the netwerk, it depends on the next blocks witch is really the confirmed block and confirmed in the whole network, the block that later rejected in the network is the stale block

4 than you are sure that the block is propagated through the whole network and you are sure the transaction didnot go back to the mempool

#590

  • What happens in the bitcoin network when two miners solve a block at the same time?
    Two versions of the blocks exist for a brief time

  • What is a stale block?
    Block that solved at same time as other but dropped due to next block being linked to other version

  • How do stale blocks occur?
    Two versions of chain, other version chosen

  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To ensure that your transaction on the block is not stale

#591
  1. What happens in the bitcoin network when two miners solve a block at the same time?

The chain splits into two chains. The longest chain will win, the transactions of the other chain will be dumped into the mempool.

  1. What is a stale block?

A stale block is a block that was dropped from the main blockchain.

  1. How do stale blocks occur?

Two miners propagate a legitimate block to the network.

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

In case of a stale block occurring.

#592
  1. two blocks are added to the same chain however part of the network will believe one version of the block to be true while the other part will believe another version.

2 & 3 A stale block is a block that was mined at the exact same time as another block but has been made obsolete by the network due to the other block having more blocks being built on top of it. since the network favors the longer chain, the stale block that started a separate shorter chain will be canceled and all transactions will be returned to the meme pool.

  1. It reduces the possibility that your block will be dropped due to being stale.
#593
  1. Both are accepted initially by different nearest nodes at random.
  2. It is a block that is dropped(accidental fork) because the longest chain is selected by all the nodes.
  3. If two different miners solve the block within same time window and transmit to different nodes, their comes a time when conflict occurs, and the shorter chain of stale block occur and thus are dropped.
  4. To ensure that it is not a stale block and does not get dropped and your Tx does not return to the mempool.
#594
  1. What happens in the bitcoin network when two miners solve a block at the same time?

Both blocks are validated until the next block is mined. When the next block is mined, the blockchain with the longest chain is accepted as true and the other block from the shorter chain is dropped.

  1. What is a stale block?

A valid block that is dropped from the chain due to another miner accepting a longer chain.

  1. How do stale blocks occur?

See 1.

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

This insures that all participants of the network have a buffer time that allows them to manage the same ledger globally.

#595

  1. What happens it that the chain forks into two valid chains, where eventually only one of those chains will win.

  2. A stale block is the block who lost the battle of the longest chain and then went to the mempool.

  3. They occur when the block with the shortest chain looses and gets moved to the mempool.

  4. The more confirmed blocks in the chain the more secure the chain is. 6 confirmations is recommended to see that the block did not get stale.

#596

Thanks Fabrice. Much appreciated.

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#597
  1. One part of the network is working based on A, another based on B block “route”
  2. A block which eventually will not be amended to the blockchain.
  3. Two or more blocks are successfully mined at the same time, however only one will be amended to the blockchain. The other(s) will become stale block(s).
#598

1- The last two minors would try to solve the target and who ever has the longer chain wins. The transaction from other chain will be dropped into the mempool.

2- A stable block is where the shortest chain get dropped into the mempool.

3- When the block is invalidated due to being the shortest chain a stale block would occur.

4- because is there chance that it become stale and it better to wait for 6 confirmation number.

#599

What happens in the bitcoin network when two miners solve a block at the same time?
Answer: There are temporarily two version of truth on the blockchain.
What is a stale block?
Answer: A block that contain a correct nonce, but is not in the blockchain.
How do stale blocks occur?
Answer: When two or more miners find the correct nonce at the same time.
Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Answer: To ensure the transaction didn’t end up on a stale block.

#600
  1. When in the bitcoin network two miners solve a block at the same time, the two blocks then compete for which will remain on the blockchain by the whichever block is used first in solving the next block.
  2. A stale block is the block that lost the competition in staying on the blockchain.
  3. Stale blocks occur when there are two blocks solved at the same time and the only option is for one to remain.
  4. It is important to wait for more than one block to be confirmed when sending or receiving a transaction (6 confirmations to be exact) to ensure no said transaction was on a block that became stale or orphaned.
#601
  1. The longest blockchain will be considered and other block will be considered as Stale block
  2. A block which was there in the chain earlier but removed at some point of time.
  3. When two miners solve the puzzle and create a block at the same time.
  4. To verify that the current block is not stale.