Homework on Stale Blocks

Blockchain and Bitcoin 101
#1364

I actually meant “one of the versions of the blockchain” but thank you for the correction

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#1365

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

Bitcoin clients always trust the longest chain, so if two blocks get mined exactly at the same time, it’s up to (51% of) the miners to decide which is going to be ‘accepted’ and which is going to be worthless.
This is one of the reasons why you shouldn’t trust only a few confirms, as the confirms could be an orphaned blockchain.

2) What is a stale block?
An orphan block, or detached block, is a valid block that is not part of a blockchain.

3) How do stale blocks occur?
This occurs when two miners produce valid blocks at the approx same time. The miner whose block is produced later or that propagates slower ends up with the orphaned block. Other nodes in the network will discard this “stale” block when they are notified of the more widely accepted block.

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

You probably already know that Bitcoin’s blockchain creates a new block about every 10 minutes through the mining process.
This block then verifies and records new transactions and appends them to the Bitcoin blockchain. This means that a transaction is unconfirmed until the new block is generated. Therefore, if you’re sending or receiving Bitcoin, it’s essential to wait until you see that the transaction has been confirmed.

One confirmation usually takes up to 10 minutes. But, since one confirmation is not enough to be confident about the validity of the transaction, users have to wait for each new block to be created to further verify the confirmation.

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#1366

  1. When two miners solve a block at the same time they both exist on the blockchain as
    two versions (fork) until a miner adds another block to one of those blocks creating a
    longer chain.The other block gets dropped and tx sent back to the mempool.

  2. A stale block is a valid mined block that was dropped because there was a longer
    version of the blockchain.

  3. Stale blocks occur when blocks are being mined too quickly and there is not enough time for them to propagate the network causing competing blocks . Miners choose one block to continue creating a longer chain causing the other blocks to get dropped.

  4. It is important to wait for more than one block to be confirmed to be sure it has been accepted, at least six confirmations so it does not end up a stale block.

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#1367

  1. Then two different versions of the blockchain are created. The blockchain that is the most difficult (longest) will eventually take over. The less difficult blockchain (shortest) will be dropped from the system and the transactions contained therein will be pushed back into the mempool until adopted by a new block on the chain.

  2. It’s a valid block on a chain that has been dropped from the decentralized network, in favor of a longer block chain. Also known as an orphan block.

  3. When a shorter chain is dropped from the system because of a split in an earlier version.

  4. To greater ensure that your transaction wasn’t validated by a block that has gone stale.

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#1368
  1. If it happens that two miners solve their respective blocks at the same time, both blocks will be initially propagated across the network with the view of being added to the blockchain. So, at that point there will be two version of blockchain available in the network
  2. A block that has initially been propagated across the network but does not eventually form part of it by being rejected is called a stale block
  3. Because of the only one version of truth accepted by the nework, it will ultimately reject one of the two newly added blocks as the next block gets added to one of the two versions of the blockchain. Therefore, a stale block it will fall away from the blockchain, with its transactions to be returned to the mempool for further processing.
  4. It is important to wait for at least six confirmations of a transaction to ensure it does not form part of a staled block that may be rejected by the network, with the transaction falling through as a result.
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#1369

It actually happens when one of the chains gets longer. The last block in the shorter chain will become stale. :slight_smile:

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#1370

It all depends on how the actual propagation played out. The accidental fork we get does not have the be equally split. It can be 50/50, 30/70 or 10/90.

It all depends on the location of the miners and how close their block minning was. I hope this makes sense. :sweat_smile:

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#1371
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    When to miners solve a block at the same time the valid block will remain the one after which the first block is linked as it results in a longer link of blocks on the blockchain. Always the longest blockchain is the valid one.
  2. What is a stale block?
    A stale block is a block that was valid at a moment but then proved to be invalid.
  3. How do stale blocks occur?
    If there are 2 blockchains at the same time and one of them proves to be valid, the other one becomes a stale block and is removed from the blockchain. The transactions of the stale block are sent 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?
    Usually after 6 new blocks are linked on the blockchain that chain is validated and proves to be the only correct chain on the blockchain.
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#1372
  1. The block with the longest chain wins and the discarded block is discarded into the mempool.
  2. A stale block is the discarded block that has not been validated and therefore returned to the mempool.
  3. When two blocks are produced at the same time, the block with the longer chain is validated and the other block becomes “stale” is eventually dropped.
  4. It is recommended to wait for all least 6 blocks to be confirmed in case of a stale block occurring and being dropped from the chain.
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#1373

  1. If the block are valid then both blocks append to the blockchain.

  2. A stale block is a valid block that has been dropped.

  3. When 2 miners solve a block at the same time and those 2 blocks append to the blockchain, sooner or later there will be another miner that by chance will mine his block based only on one of those blocks and that will be the blockchain that the network accepts. The other block will be dropped and those transactions will be put back in the mempool. This is how a stale block occur.

  4. You have to wait for 6 confirmations just to be sure that the block with your transaction won’t be dropped and so your transaction return in the mempool.

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#1374

  1. When two miners solve a block at the same time then some nodes will be working with one version of the blockchain while other nodes will work with a different version of the blockchain. Eventually the longest chain will be the correct blockchain and any transactions from the other blockchain will return to the mempool.

  2. A stale block is from a version of the blockchain that has been dropped.

  3. Stale blocks occur when there are two versions of the blockchain and the shorter one is dropped.

  4. It is important to wait because even if a block is confirmed it could later be dropped if there is a longer version of the blockchain.

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#1375

1.when you have 2 block solved at the same time the block in the longest chain will win and the other block will return to mempool
2. A Stale block is a block approved and was in the blockchain but got dropped for another block create at the same time but is part of a longer chain .
3.when 2 miners create 2 block and got confirmed and add to the blockchain at the same time but then is dropped because the other block is part of a longer chain
4,it is important in order to see that do not get dropped the best is wait for 6 confirmations.

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#1376

1 - When 2 miners solve a block at the same time. the one with the longest block-chain wins and the other one dropped and the transactions returned to the mempool.

2 - A stale block or orphaned is the block that was on the blockchain that have the shortest block chain , and was dropped .

3- A stale block occur when 2 blocks were valid at the same time creating 2 truth blockchain , and one continue with the other block bringing the other one to drop.

4- It is important to wait for 6 confirmations to be sure that the block your transaction are in , is not dropped from from the chain.

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#1377

  1. When two blocks occur at the same time and both have nodes to support their claims are kept on the chain temporary until the following block is mined to determine according to his own version, which chain is the correct one.

  2. A stale block is also known as an orphan block. Basically is a block initially appended to the network but later made redundant and detached.

  3. Stale blocks occur when more than one block is mined and the following block approve one and made the rest redundant.

  4. As the blockchain data needs to travel physically some times stale blocks might occur. Therefore, the best practice is to wait for 6 confirmation before you are sure your transaction has been processed.

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#1378
  1. to separate and valid chains emerge.
  2. a once valid block that was dropped because it was not part of the longest chain which was accepted by the system.
  3. when a valid block leads to other valid blocks which in the end are not part of the longest chain so are dropped by the system and the data is returned to the mempool.
  4. to ensure your data is not part of a stale block and returned to the mempool.
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#1379
  1. Assuming these blocks pass through nodes without knowledge of each other, other miners will build on each of these chains. When the system becomes aware of the difference between two valid chains, the longer chain is chosen and the other eliminated.
  2. A stale block has been orphaned because a competing chain is chosen by the decentralized nodes as truth.
  3. Stale blocks occur as a result of chosing one block chain as truth while eliminating a competing chain. The eliminated chain is identified as stale blocks.
  4. It takes time to propagate a chain throughout all nodes and some transactions in stale blocks are returned to the mempool. By design the goal is at least 6 confirmed blocks (or approximately 10 min) to be added to the winning chain so that transactions are not dropped.
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#1380
  1. The next block mined will attach to one of the two and that will be longer chain and the other block will be ignored
  2. The block that gets ignored from Q1
  3. See Q1
  4. to make sure the block does not get dropped
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#1381

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    the longest blockchain will win and join the network and the other one will be dropped and join the mempool

  2. What is a stale block?
    a block that dropped to mempool against another block with more pow

  3. How do stale blocks occur?
    when 2 miners mine block at the same time one of them will go stale and drop back to 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 block contains the TX is used and not dropped

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#1382

  1. The chain splits, and the longest chain gets added to the blockchain and the orphan blocks transaction goes back to the mempool

  2. A block that was dropped from the “race” when miners mined simultaneously, and has to start confirmation process all over again, from the mempool

  3. Because multiple miners work on the same blocks at the same time

  4. Because it might not go through because of the simultaneous mining and you need to start all over again

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#1383

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    At this point there is a situation with two truths, i.e. a temporary fork is created. At the end one chain will win, the one with most PoW.

  2. What is a stale block?
    A block that has been on the blockchain for a while and then has been removed, whereas the transactions move back to the mempool. Also called Orphane Block

  3. How do stale blocks occur?
    When two miners create two different blocks and put it on the Chain at the same time, not knowing of each others block. This may occur due to geographical distance

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    You don’t want to be the Stale block or your transaction being in a stale block.

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