Homework on Stale Blocks

Blockchain and Bitcoin 101
#422
  1. Both blocks start their own blockchain and are validated. 2 versions of truth.
  2. A stale block is a block which was validated or confirmed but is then dropped because the other “version of truth” has more PoW.
  3. Stale blocks occur when their are 2 versions of truth but 1 new miner appends to 1 of those versions and makes longer that specific blockchain, giving it better PoW so the other block is dropped, back to the mempool.
  4. It is good to wait to see if that chain has been accepted. Longest blockchain, the more PoW.
2 Likes
#423
  1. The one that is longer and has a higher pow difficulty will be accepted
  2. A block that was not accepted by the blockchain
  3. When different nodes have different transactions and only the ones with longer and higher difficulty get accepted.
  4. To be sure it is a valid transaction.
1 Like
#424
  1. The block is appended and the next miner who picks up one of the blocks will continue and the other block be dropped with the transactions going back into the mempool
  2. blocks that were in the blockchain at one time then got dropped because of a longer chain
  3. when a fork occurs between two blocks and the block that has the shorter chain
  4. To prevent the possibility of a stale/orphaned block from occuring
2 Likes
#425

[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?

When a block is propagated to the nearest nodes and two different miners solve a block puzzle at the same time and both are a correct version on the blockchain, the chain will fork temporarily and will co-exist at the same time, until the next miners adds a new block to one of the possible chosen chains by the nodes.

Once a new block is added by a new miner to one of the forked co-existing blocks chosen by the nearest nodes, eventually the longest chain will be favoured as the true block by the majority of the nodes and the other block will be orphaned and returned to the mempool.

2) What is a stale block?

A stale/Orphaned block is a block which is dropped from the transaction chain to the mempool in favour of the longer blockchain.

3) How do stale blocks occur?

A stale block occur when competing miners add two acceptable different blocks to the chain at the same time, and therefore the blockchain forks temporarily until a new block is added by a new miner to one of the forked co-existing blocks, which is chosen by the nearest nodes. Eventually the longest chain will be favoured as the true block by the majority of the nodes and the other block will be regarded as stale block and therefore returned to the mempool.

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

To ensure that a transaction is not in a stale block and dropped back into the mempool, it is wiser to wait for at least 6 new block confirmations on the network (about an hour or so), after that your block transaction would 100% confirmed.

2 Likes
#426

  1. When two miners solve a block at the same time there will be two blocks that are created and start to propagate throughout the network. Because the miners may not have chosen the same fees for their blocks they could contain different data and information.

  2. A stale block (some people say orphaned block) is a block that has been dropped from the network.

  3. A stale block will be dropped from the network after a time, because the network has chosen to continue the chain using a fork of the chain that does not include the stale block. Since the blockchain with the chosen block is now longer than the version with the stale block, the network will recognize the longer chain as the true chain. All of the transactions in the stale block which were not covered in the block chosen to be the true block are then returned to the mempool.

  4. It is important to wait for more than one block to be confirmed by the network, because it can take a number of blocks before the network determines that a previous block will be dropped as a stale block.

2 Likes
#427
  1. The longest chain prevails. The stale or orphaned block is returned to to mempool.
  2. A stale block is one that does not have any further block linked to it.
  3. When two blocks are mined at the same time it causes a split in the chain and the tie is broken by the next mined block.
  4. You want your transaction confirmed on the longest chain, so wait
2 Likes
#428
  1. What happens in the bitcoin network when two miners solve a block at the same time?

They are both appended to the blockchain creating two versions of truth in the blockchain that will spread until another block is created and appended to one of them leaving the longest version, the one with more proof of work.

  1. What is a stale block?

A block that has been dropped of the blockchain.

  1. How do stale blocks occur?

When a branch of the blockchain has more proof of work than the other, then the blocks from the shortest branch will be discarded.

  1. 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 is in the branch that will continue

2 Likes
#429

When 2 miners solve a block at the same thing, both blocks are considered valid until the next block is produced. The block that is produced after that will become the most valid chain as it is the longest chain that shows Proof of work.
a Stale block is a block that was produced during the same time as another block but did not beat the time of the next block found from the other chain.

Stale blocks occur when two blocks are valid and produced at the same time.

It’s important to wait more than 1 block for confirmations because there can be multiple instances where both blocks are valid but produce another block with both the same set times as well.

2 Likes
#430

  1. Both will be propagated (because they will be sent to nodes in the closest proximity), sort of like a superfluous fork, until the longer chain wins and is verified.

  2. A block that has been ‘orphaned’ or discarded back to the mempool.

  3. A block can be invalidated by superior POW. When two chains compete, ultimately one wins.

  4. The nature of the blockchain means that a particular block could be orphaned, thus it is prudent to wait for multiple confirmed blocks.

2 Likes
#431
  1. Both will propagate until one gets longer and is chosen by the system.
  2. It’s one of two simultaneous blocks. It is the one not chosen by the system.
  3. Occurs when it is not chosen by the system and sent back to the mempool.
  4. You need 6 confirmations after the first block in the event there is a simultaneous transaction.
2 Likes
#432
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    two version of block exist but the one with the longest chain wins
  2. What is a stale block? block that loses in this scenario
  3. How do stale blocks occur? block with shortest chain
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? to make sure you get approved by the system
2 Likes
#433

  1. When two miners solve a block at the same time, two competing blockchains are created. Whichever is appended to first will survive and the competing one will be dropped, orphaning the block and returning the transactions to the mempool.

  2. A stale block is the block that is on the competing blockchain that is dropped and whose transactions are returned to the mempool.

  3. Stale blocks occur when miners solve a block at the same time. Depending on their geographical location, two versions of the blockchain begin to propagate across the nodes in the network. Whichever version is appended to first becomes the “right” version. The transactions from the stale block are then returned to the mempool.

  4. It is important to wait for more than one block to be confirmed (best practice is 6) when sending or receiving a transaction to ensure that it isn’t part of an orphaned block and returned to the mempool. After 6 confirmations, the transaction is confirmed and cannot be altered.

2 Likes
#434

  1. They each have a version of the transaction…the deciding factor will be the 3 rd miner and which block he confirms. The block that has not been choosen will return to the mempool and be disposed of.

  2. Whenn2 miners minenthe same block and 2 version of the truth excist. The block that get dropped is called a stale block and get returned tonthe mempool and removed.

  3. When 3 miners simultaneously mine the same block.

  4. This insures that a transaction is not processed in a stale block.

1 Like
#435
  1. There are now two versions of the blockchain. But eventually miners working on one version will generate blocks faster than the miners on the other version, and the network will agree on the longest blockchain to be the valid blockchain.
  2. A stale block is a block which exists on a version of the blockchain which is no longer worked on by miners, and no longer seen as valid by the network.
    3, They occur when miners abandon the shorter version of the blockchain.
  3. To make sure that the version of the blockchain which your transaction was validated is the version which the network accepts. If the blockchain in which your transaction was validated in turn stale, or orphaned your ytansaction is no longer valid.
2 Likes
#436

A stale block was a valid block, but because 2 miners found a block at the same time, some nodes have a different version of the blockchain, it will depend on wich of those 2 versions the next miner will successfully mine the next block on top of it. So this blockchain will be longer than the other version. Then all nodes will use the longest blockchain as the current valid blochain, the block that got dropped, those transactions wich were not included to the ‘winning’ block, will go back to the mempool

1 Like
#437

Transactions that are in the ‘winning’ doesn’t go back to the mempool. Because they stay on the blockchain, they are already confirmed. Transactions wich were not in the ‘winning’ block will go back to the mempool waiting for another miner to get confirmed.

1 Like
#438

when 2 miners mine a block at the same time, 1 will eventually drop from the network.
(not when 2 transactions are created at the same time)
In 1 block, there are lots of transactions. Every new transaction get into the mempool, where miners will pick from to add into a block until the block is full. Then they need to mine it successfully. (by guessing a nonce, hash the block, and check if the hash is below target)

#439

You have basically 2 correct versions of the blockchain (fork) for a while, until another miner mines a new block on 1 of these valid blockchains. It’s not about wich block was first. If you have 51% of the hashpower in a POW blockchain, You can even shadow mine, by mining lots of blocks offline and announce your blockchain later on. In proof of work blockchain, the nodes will accept the longest blockchain as the valid version of truth

2 Likes
#440

Thanks for clearing that out!!
Awsome with the feedback.

2 Likes
#441

1- the blockchain will accept the blocks if the information is true, and will create two different versions of truth on the blockchain. In the end the longest chain will win, and the other block will be dropped becoming a stale block.

2- A stale block, is a block that was accepted on the blockchain but it has been dropped, because it has a different version of truth.

3- Stale blocks occur when a block was valid for a while because 2 were produced with the same version of the truth but then dropped because the blockchain continued on another block.

4- it is important to wait, because your transaction could be in a stale block that will eventually be dropped returning your transaction to the mempod, where it will be eventually be mined again on the blockchain with the right version of the truth.

3 Likes