Homework on Stale Blocks

Blockchain and Bitcoin 101
#3551
  1. What happens in the bitcoin network when two miners solve a block at the same time?
  • The block with additional blocks after it will be included in the blockchain even though both blocks are valid. The true blockchain is determined by the network as a function of chain length and proof of work. A long chain with little PoW will be discarded over a shorter chain with more PoW.
  1. What is a stale block?
  • Valid blocks that are not included in the blockchain are referred to as stale or sometimes as ‘orphaned.’
  1. How do stale blocks occur?
  • Stale blocks occur when the miners are not fast enough to propagate the block to enough nodes to be included in the chain before other valid blocks are added.
  1. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
  • It is important to wait for 6 confirmations (about 1 hour @10min per block) to ensure your transaction is not apart of a stale block.
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#3552

  1. What happens in the bitcoin network when two miners solve a block at the same time? | When two miners solve a block at the same time, an accidental fork occurs, which splits the blockchain in to two different versions, and when one blockchain gets the most PoW the other’s blocks will be turned into stale blocks.

  2. What is a stale block? A stale block is a block that has been discarded after an accidental fork, with the information inside them returned to the mempool.

  3. How do stale blocks occur? | See question 1.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? | Because otherwise your confirmed transactions inside a block could be turned into stale blocks, with the transactions cancelled.

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#3553
  1. Network eventually keeps the block in the longer chain.
  2. A solved block that doesn’t become part of the longer chain.
  4. it can become stale
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#3554
  1. the longest chain wins and the other block is discarded and considered a stale or orphaned block

2)A block that was mined correctly but eventually was not on the longest chain

3)Stale block occurs when you have two miner come out with the same outcome. But then next block mine follow one or the other on the chain. The chain that doesn’t continue will get dropped. and the fork that continue will become the longest chain

  1. Best practice is to wait for 6 confirm transactions to be sure that the block your transactions are in is not dropped from the chain
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#3555
  1. What happens in the bitcoin network when two miners solve a block at the same time?

For a short period of time we will have 2 versions of the blockchain, until one of them (the shorter one) will be discarded.

  1. What is a stale block?

A valid block that has been discarded from the chain due an accidental “fork”.

  1. How do stale blocks occur?

When 2 miners finish a block at approximately the same time and/or the changes in the chain are not propagated fast enough, so miners choose to continue on different blocks causing a temporary fork. One of the chains in the fork will eventually be dropped, the blocks in it will become stale and the transactions included again in the mempool.

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

To reduce the risk of the blocks where our transactions where included to become stale.

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#3556

  1. There will be two version of the truth.

  2. A stale block is the block dropped and ignored by the system.

  3. When two miners solve a block at the same time and one of the version is dropped.

  4. To reduce the odds of becoming a stale block.

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#3557

It merely reduces the chance of your transaction being dropped because of being included in a stale block. :slight_smile:

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#3558

When two miners solve a block at the same time, the blockchain splits in two. When a third miner comes along, he will have to decide which block to build his next block upon, the one chosen will create a longer blockchain than the other and thus the network will accept that blockchain as truth and get rid of the other block and return the transactions to the mempool. It is important to wait for more than one confirmation because the confirmed block might get returned to the mempool.

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#3559
  1. This happens when two miners solve a block at the same time:

  • for a limited period of time, both versions will be propagated into nodes network

  • at some point, another miner will append his block to only one of the two previously created

  • and so, the network accepts the longer blockchain (in terms of PoW, not actual number of blocks)

  • the blockchain that was NOT picked by the miner is removed and the last block becomes STALE BLOCK

  • the transactions from the stale block go to mempool again

  1. A stale block is a block that existed in a blockchain and has been dropped because there is another longer blockchain.

  2. Stale blocks occur after a miner picks up one of the valid blockchain variants circulating to append a new block - and the last block from the blockchain that has not been picked becomes orphaned (stale block).

4.It is important to wait in order to avoid the possibility for your blockchaint to be dropped. The best practice is considered to be 6 confirmations. Basically, you need to wait for another 6 blocks to be created to be sure that the transaction is confirmed.

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#3560

  1. At first, 2 versions (fork) of BC are created. Reduced to one longest BC as soon as a 3rd miner attaches a block to either, causing this longer one to win as new BC version.

  2. Discarded block from the shorter BC version that lost the race to add valids blocks as above. Back to mempool.

  3. Blocks on the losing side after a fork is resolved with anoteher longer chain.

  4. To be sure it does not become a stale block. After 6 more blocks are attached/created there is assurance of acceptance by the decentral network/BC.

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#3561
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    The chain will split temporarily, until a miner chooses a block to build off of, therefore invalidating the other split block that became shorter.
  2. What is a stale block?
    Blocks that were in the blockchain at some point, but they were removed because another version of the blockchain became more valid.
  3. How do stale blocks occur?
    Two miners mine a block at the same time, creating a temporary fork in the blockchain.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    A block can be dropped in the case of multiple versions of truth, so waiting for another transaction helps in avoiding an orphaned block.
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#3562
  1. The network will accept the block who have the longest chain and the other one will be remove and all the transactions from this block will return into mempool.
  2. Rejected block by no chain into or smaller chain than other block.
  3. When occur two version of the truth and propagated in the network in the same time .
    4.To be sure that your block it does not end up being eliminated.
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#3563

  1. The network will accept momentarily the two block and they will propagate normally until one of the two branch of the blockchain create a another block of top of it, them it will be the longest chain and it will propagate and be pick by the network a the valid chain. The another branch will be deconstruct and put in the mempool.

  2. A stale block are block who where in the blockchain at one time and get drop because the network found a chain longer that the one they where in.

  3. When the blockchain generate block at the same. That for why they get a target of 10 min, that minimize the apparition of those block.

  4. Because your block might get dompt because is was in a stale block.

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#3564

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

    Both miners are gonna be propagating their block around the network, and whichever version of the blockchain becomes longer (more PoW) gets accepted by the network. The other block becomes a stale block.

  2. What is a stale block?

    It’s a block that was solved and was being propagated, but in the end it was dropped and not accepted by the network because another block solved at the same time was part of a longer chain.

  3. How do stale blocks occur?

    When 2 blocks are solved at the same time, one of them becomes part of a longer chain and continues the blockchain, the other gets rejected and becomes a stale block.

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

    Because that one block could become a stale block and all the transactions will return to the mempool.

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#3565

  1. What happens in the bitcoin network when two miners solve a block at the same time? Two versions of the blockchain exist and are being propageted around the network.

  2. What is a stale block? A stale block is a block containing valid transactions that is rejected by other miners in the network.

  3. How do stale blocks occur? Stale blocks occur when another longer circulating version of the blockchain is accepted by mining nodes as the truth, and other blockchain versions are dropped by the network.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction? Allow sufficient time for all new versions of the blockchain to propogate through the network so that more than 51% of the miners agree on the correct version of the truth.

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#3566

  1. The chain splits into 2 potential versions of truth, meaning both valid.

  2. A block that was successfully mined but not included on the current longest blockchain.

    Although used interchangeably, it is not to be confused with orphaned block.
    https://btcinformation.org/en/glossary/stale-block

  3. Stale blocks occur when another miner adds a block simultaneously (perhaps solving the nonce at equally the same speed), hence creating a fork. From the point of the fork, more blocks will be added and whatever “prong” ends up longest is what will eventually be considered the only truth and thereby the other prong will eventually be dropped.

  4. To avoid complacency as 1 confirmation does not always mean your transaction didn’t land on the chain that is about to be dropped or orphaned.

I find this a valuable supplementary read:
https://medium.com/@cryptobolts/what-are-stale-blocks-simply-explained-b445682274c6

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#3567

When 2 miners solve the block at the same time; they both get attached and will be waiting to see which one of them gets dropped ( it will be the one that is not a part of the longer blockchain)
The block that gets dropped is a stale block.
It is important to wait 6 confirmations to be sure that blocks do not get dropped and don’t go back to mempools (and get a status of a unconfirmed transactions)

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#3568

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Both of the blocks are added to the blockchain and it forms a fork.

  2. What is a stale block?
    A stale block is a block that was once in the blockchain, but got dropped and went back into the mempool.

  3. How do stale blocks occur?
    When more blocks are added to one of the chains, that chain becomes the only viable version, because it has the most PoW and other blocks that were not part of that chain become stale blocks.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    So that the current block doesn’t become a stale block.

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#3569
  • What happens in the bitcoin network when two miners solve a block at the same time?
    when its solved at the same time, the longest block chain wins, the other block is orphaned and sent to the mempool.
  • What is a stale block?
    A stale block is a block that was dropped in the blockchain due to an occurence of a fork.
  • How do stale blocks occur?
    a stale block occurs as only one version of the blockchain is accepted and the other is accepted by the network.
  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    as there can be more that 1 version of the truth is is advisable for 6 confirmations
    [/quote]
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#3570

True there is a difference but as you mentioned they are used interchangeably. Most people user orphaned blocks. :slight_smile: Good catch :raised_hands: