Homework on Stale Blocks

Blockchain and Bitcoin 101
#2049

The two blocks will be valid until a new miner solves the following block and attaches it to one of the two previous ones, confirming the longest chain and discarding the shorter one.

Stale blocks or orphan blocks are blocks that were dropped from the network by other longer chain.

Stale block occurs when a miner picks a chain to attach their new block, becoming this chain the larger one and dropping the shorter chain which contains the stale block.

It’s good to wait for more than one block (six is recommended), to be sure that your UTXO is not in a stale block, and it gives time to sync up the network.

1 Like
#2050
  1. The chain will start to split.
    2.and 3. A stale block is a block the losing chain from when the chain split into two because two miners solved the nonce at the same time.
    4.Its important to wait because the one you’re trying to confirm could be apart of the split chain that will become stale.
1 Like
#2051

  1. 2 blocks are generated splitting the chain in 2, which is later fixed by cutting of the shorter end.

  2. A block that has been mined at the same time as another one, but the second one becomes part of the longer chain so the one in question is cut off the chain and all transactions in it are taken back to the mempool.

  3. As explained above - when 2 blocks are generated at the same time and later on one of them is cut off.

  4. Because if you go with only one - there is always a chance for this particular block to end up being a stale one.

1 Like
#2052
  1. Initially each of the blocks will get added to nodes close to them. Eventually one of the two blocks will become stale/orphaned and dropped from the block chain.
  2. A stale/orphaned block is a block that is getting discarded because another version of the blockchain is longer and has more blocks on it.
  3. Stale/orphaned blocks happen when two miners find a solution to the puzzle at the same time and are adding new blocks to the same blockchain.
  4. So that you know that your transaction has become an immutable part of the blockchain and is not going to become part of a stale/orphanced block.
1 Like
#2053

  1. When (2) miners solve a block at eh same time, the blockchain splits until the next miner choose one and the other gets removed.

  2. A stale block is one that got removes from the blockchain.

  3. A stale block occurs after (6) confirmation. The chain with the longest block wins and the other get orphaned and thus become stale.

  4. It is important to wait for more than one block to be confirmed because it is possible that you may be in the chain that gets staled or orphaned.

#2054

Homework on Stale Blocks

  1. What happens in the bitcoin network when two miners solve a block at the same time?
  • Initially both blocks will be accepted by nodes closest to them. This results in temporarily having two chains.
  1. What is a stale block?
  • It is a mined block that at some point was accepted as valid by one or more nodes but then got rejected because it wasn’t of the longest chain anymore.
  1. How do stale blocks occur?
  • When two blocks are accepted at the same time two chains exist. After a while another block will be mined and be appended to one of the chains. This chain will now become the longest chain and all nodes will accept this one as truth. The block that was appended to the shorter chain becomes a stale/orphaned block and its txs are returned back to the mem pool.
  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
  • To make sure the tx was not part of a block that became stale.
2 Likes
#2055

yes, and because you can only have 1 block on the same blockheight, the blockchain will temporarly fork until 1 of these 2 blockchains gets longer. (Depends on wich version the next miner will succesfully mine a new block)

2 Likes
#2056

the six confirmations means that six more blocks are mined. stale blocks happen when 2 miners mine a block at the same time. because you can only have 1 block at a certain blockheight, the blockchain will fork in 2 different blockchains with a different last block. then it depends on wich of these 2 versions the next miner mines a new block on top wich makes 1 version longer than the other. the block on the shorter blockchain will become a stale block.
The more confirmations, the harder it gets to reorg the blockchain.

1 Like
#2057
  1. Both blocks connect to the chain, and the block with the longest chain will win and become the new chain, while the other block is orphaned. Any transactions from the orphaned block is sent back to the mempool.
  2. A stale block is the orphaned block.
  3. By two blocks being produced before the 10 minute mark, the nodes will choose the closest miner with the longest chain being chosen
  4. To ensure that a stale mate does not occur.
1 Like
#2058
  1. What happens in the bitcoin network when two miners solve a block at the same time?
  • they will start to propagate the block to the geographically closest nodes, so it may happen that half of the network have different chain than the other one
  1. What is a stale block?
  • stale block is a valid block which was dropped by the network because it was not part of the longest chain
  1. How do stale blocks occur?
  • it happens when two miners solve a block at the same time and then other 2 miners start mining on these 2 different blocks. The faster miner will determine which chain will be the main chain and the previous block will be dropped.
  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
  • because the block could be dropped and become a stale block, e.g. the transaction would be reversed
1 Like
#2059
  1. What happens in the bitcoin network when two miners solve a block at the same time?
  • The chain splits temporarily but the chain with the most PoW will be chosen and the other dropped or made redundant (stale)
  1. What is a stale block?
  • A block of data that was dropped from the chain due to a more favourable block containing more PoW in a longer chain.
  1. How do stale blocks occur?
  • When multiple miners are mining a different version of the chain that are still valid at the time however the blockchain will always favour the version with most PoW.
  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
  • It’s important for 6 confirmations to ensure your TX in the chain has not been dropped as part of a stale block. This ensures that your TX has been written in the chain and confirmed in 6 blocks validated and confirmed.
1 Like
#2060

Both block starts to propagate through the network.

A stale block is a block that was rejected by the network because another, competing branch grew faster.

Multiple blocks are being mined and propagated through the network at the same time. The network will choose the longer validated chain, so when any of these simultaniously existing blocks get a new block on top of them validated faster, the competing blocks will be pruned. These blocks are stale blocks.

To avoid the possibility that the block for this transaction gets rejected by the network aka becomes a stale block.

1 Like
#2061

  1. Both blocks will get added to the blockchain till the next block decide which block will form the longest chain so the block on the shorter chain will get dropped.

  2. A stale block is a well-formed block (in which ash under the set target) which is no longer part of the longest and well-formed blockchain and gets dropped.

  3. it occurs when two miners solve a block at approximatively the same time and get validated by the closest nodes.

4.So we are sure a fork will not be formed, we will get the longest chain and our block and transaction get validated and not discarded.

1 Like
#2062

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Each block is appended to the block chain in different groups of nodes, but mining continues and blocks keep being appended eventually the longest chain stays and the other branch is discarded.

  2. What is a stale block?
    It is a block or chain of blocks that gets discarded when a longer chain of new blocks is appended to the blockchain.

  3. How do stale blocks occur?
    When the system chooses the longest chain the branch containing the other blocks, get discarded and the transactions go back to the mempool.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Because this transaction however being in a confirmed and added block, it might get stuck inside a Stale chain and get discarded.

1 Like
#2063
  1. The chain splits creating 2 versions of the blockchain and the block that gets chosen to continue the chain thus creating a longer chain will win out as the network will always choose the longest chain to continue on.
  2. Stale Block is a result of two miners finding the block at approximately the same time and one will be chosen and one will be dropped. The dropped block is known as a “stale” block.
  3. When two miners solve a block at approximately the same time creating two versions and a new miner enters and chooses one of the versions to continue mining the chain the block not chosen gets dropped creating a “stale” block.
  4. It is possible that the block where the transaction lives can become a stale block which will be dropped from the chain rendering it invalid and sending all transactions in that block back to the mempool to be re-validated.
1 Like
#2064

Actually the blocks might even be mined after that, the block time is an approximation. It is because they are mined at approximately at the same time.

Not sure what are you referring here as stale mate. But the reason why the user must wait is because his tx might be part of a stale block. :slight_smile:

1 Like
#2065
  1. Another miner validates on and becomes the longest chain with highest proof of work.
  2. When a block gets dropped for a longer blockchain.
  3. When two miners solve a block at the same time.
  4. Minimize the issue with orphan or stale blocks.
1 Like
#2066
  • What happens in the bitcoin network when two miners solve a block at the same time?
    –There are two version of the truth. So when a miner picks one of the blocks to mine, this chain becomes longer and will most likely be accepted by the network, while the other block(stale block) will be dropped and the transactions within that block will be sent back into the mempool.
  • What is a stale block?
    –A stale block is a valid block that has been dropped due to a competing block that was accepted into the network.
  • How do stale blocks occur?
    –When a block is competing with another block that is part of a longer chain, the shorter block (now stale block) is dropped from the network and sent back to the mempool.
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    –6 confirmations is the safe number and this ensures that your block is part of an already larger and growing block which will help the network choose your chain over a shorter one thus propagating the transactions to the rest of the network, and keeping it confirmed.
1 Like
#2067

  1. There is a race to determine which competing version of the next block has the most support. It’s survival of the biggest hash rate.

  2. A stale block is one on a dying chain that has lost the battle to be the chain of the future. In that case, those transactions will be returned to the mempool for inclusion in future blocks on the WINNING chain.

  3. When a nonce is found to ensure a hash for a block below the current target at EXACTLY the same time as another nonce is found to ensure a hash for ANOTHER “Winner” is below the current target, the race begins to determine which block will become the progenitor of the future chain. THERE CAN ONLY BE ONE !!!

  4. More blocks added to the chain after the block containing your transaction (more than 1 confirmation) is required to ensure that the block in which the transaction is contained is actually on the WINNING blockchain and not a part of an ORPHAN block.

1 Like
#2068

Only one block can contain the same tx. Each subsequent block to said block is another confirmation to a transaction. :slight_smile:

1 Like