Homework on Stale Blocks

Blockchain and Bitcoin 101
#1929
  1. What happens in the bitcoin network when two miners solve a block at the same time?

Two different versions of the blockchain are propagated throughout the network. Eventually, one of the blocks becomes orphaned, depending on which blocks obtains a subsequent block.

  1. What is a stale block?

Stale blocks are blocks that are added to the longest chain. They are blocks that never have blocks added to them. Essentially, they are dropped from the network as they are no longer considered the longest chain.

  1. How do stale blocks occur?

Stale blocks occur when blocks are mined simultaneously. This is because the network does not have enough time to propagate the longest chain across the network, so half the network may have one version whereas the other half has another version.

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

This is important because the block the transaction is included in could be orphaned/stale.

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#1930
  1. They both begin propagating their block, resulting in two competing versions of the blockchain propagating through the network.
  2. A stale block is a valid block that was dropped from the blockchain.
  3. When miners chose a competing valid block to append their new block to and this chain becomes the longest, the valid block that was not included is dropped and its transactions returned to the mempool.
  4. To make sure the block in which the pertinent transaction is included is not later dropped. By waiting for six blocks, it is reasonably secure that our block is now a permanent part of the chain.
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#1931

  1. They are both valid and they both get their blocks added to the network where half of the network
    gets the version of the first miner and the other half gets the version of the second miner, but only
    the one that will be in the longest chain will remain and the orther and all the blocks that follow that
    one will become a stale block and all the data of these blocks will get put back in the mempool.

  2. A dropped block.

  3. Stale blocks are blocks that where in the blockchain but got dropped because there is another
    version of the blockchain that is longer without those blocks in it.

  4. Just to be sure that your transaction isn’t in a block that gets dropped. You must wait for 6
    confirmations .

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#1932

  1. It all depends on who mines the next block and it is not deterministic. Furthermore, the longest chain always wins in this kind of situation

  2. Stale blocks are basically abandoned or not accepted blocks in the main chain

  3. Stale blocks occur when they were produced by building on a block that is no longer the active tip of the chain. Some nodes may have considered it to be the best block at some point, but they switched to another chain that does not contain the relevant block anymore. They are valid, verified, and their ancestry up to the genesis block is fully known - they’re just not currently ‘active’.
    4.At least wait for 6 confirmations to make sure that the blocks with the valid transactions don’t get invalidated from the chain.

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#1933
  1. There will be 2 block chain paths but the next miner to solve a block on the chain to make it the longest chain will validate that block the other chain will drop the transactions back into the mempool.
  2. A stale block is a block that has been unvalidated based on the existence of a longer chain.
  3. A competing block has more confirmations and has a longer chain than the other block.
  4. Blocks are competing so the confirmation validates the longest chain is being used and therefore is the correct block chain.
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#1934

  1. This will create 2 versions of the block chain the shorter version will eventually be dropped from the blockchain and all the transactions returned back to the mempool.

  2. A block becomes stale when it forms part of the chain that has been dropped by the network.

  3. A stale block occurs when two or more miners complete a block at the same time and only one block is accepted as the truth.

  4. Because your transaction might form part of a block that gets dropped from the network.

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#1935

1- you wait to see which block chain will be longer
2- a block that is dropped because it ends up in the shorter block chain
3- when two blocks are added at about the same time, but only one is chosen
4- because you don’t know if that block will be dropped or not

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#1936
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    The miner with the most confirmed blocks will be adopted (i.e. the one with the most blocks that appends after it will be confirmed)
  2. What is a stale block?
    Those competing blocks that were not confirmed
  3. How do stale blocks occur?
    They are not confirmed because they have lesser confirmations than the one that was adopted
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Just to be extra safe in making sure that block is adopted by the network
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#1937

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    The nodes pick up the closest miners transaction and the miner who succeeds the other miners blocks go back into the mempool.

  2. What is a stale block?
    A block that was not in the longest chain that gets rejected and discarded.

  3. How do stale blocks occur?
    When two miners compete for the next successful block the miner who doesn’t succeed his block becomes stale.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To prevent your blocks from becoming stale and not putting the energy used to create the block to waste.

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#1938
  1. They both create a new version of the blockchain. This version will get broadcasted and some nodes will get the one version and some nodes will get the other version.
  2. A stale block is a block that has been in the blockchain on some nodes, but is dropped due to not being part of the longest chain/ blockchain with the highest PoW.
  3. When two versions are broadcasted to the world, there are two versions of truth. A miner will randomly chose a certain node and look at its blockchain. It will select transactions and try to append them to (one version of) The blockchain. When this miner is the quickest to solve the puzzle, this version of the blockchain will have the most PoW and will therefore be used further. The other version of the truth, of which the miner was not quick enough at solving the puzzle, wont have the longest chain anymore. The blocks that were in this blockchain but not in the newly accepted blockchain, will be dropped and its transactions will be send to the mempool. This is how a stale block can occur.
  4. It could be a stale block. This would cause you to think the world has accepted is as the truth while in fact it is not yet seen as the truth by the world.
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#1939

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    They both propagate their block to the network and as the time goes by the network chooses the longest chain with most POW.

  2. What is a stale block?
    Is a varied block that got dropped from the blockchain due to the longest chain winning

  3. How do stale blocks occur?
    When there are two version of truth the network choose and extend the chain with most POW and the shortest chain is dropped resulting to stale block.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To be certain that your transaction is actually included in the longest chain of blockchain and this minimizes the risk of being included in the stale block.

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#1940

Miners will mine on a block that is either stale or not, atm they cant know if their block will be accepted or not.
Why is it important from the perspective of the user that is trying to send or receive a tx? :slight_smile:

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#1941

I’m going to guess its because their transaction stays pending until it is picked up by a miner?

#1942

The transaction is already mined. But in case of an accidental fork it might be part of a stale block that will eventually get dropped and the tx would be returned to the mempool. :slight_smile:

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#1943

  1. Two different blockchain versions start propagating throughout the network. Like ‘mob rules,’ the miner nodes that pick up one version more than the other collectively determines the real blockchain (the longer blockchain). Interesting how the physical and geographic aspects of a blockchain come into play.

  2. A block that’s dropped from the blockchain.

  3. More than one miner mines a valid block within a period of time allowing the different blocks to start propagating throughout the network. At some point the network will only recognize one version, the longer chain. The rejected blocks/versions are cast aside (to the mempool).

  4. Waiting 6 confirmations allows sufficient time/confirmations for the network to solidly the real/forever blockchain.

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#1944

What happens in the bitcoin network when two miners solve a block at the same time is the block with the most proof of work will be the block that is added to the blockchain. This can happen by way of another miner adding a block to one of the competing chains, and the chain with the more proof of work recorded will end up winning the place while the other block is considered “stale” or “orphaned” and it’s transactions are moved back to the memepool

It is important to wait for more than one block to be confirmed as your transaction can be existent in one of these stale blocks and thus not complete being sent or received.

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#1945

1.The chain forks temporarily
2. The block of the shortest chain after a fork, which will be moved to the mempool
3. Happens if 2miners solve the puzzle at the same time. So both blocks are added parallel to the block, but one chain is not used.
4. Because you never know if your transaction will be in the stale block or not. Waiting six confirmations should be enough to be ensured about validation of the transaction.

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#1946

  1. When two miners solve a block at the same time initially both blocks will exist. However over time new blocks will be added to ONE of the blocks at a faster rate than the other one and this block will end up being part of the longest chain.

  2. A stale block is a block that was part of the blockchain at one point in time but subsequently ends up being not being part of the longest chain.

  3. See answer to question 1. Stale blocks are ones generated at a similar time to a block forming another chain branch that end up being outpaced by the other branch and hence become a shorter and hence non-authoritative chain

  4. Waiting for 6 confirmations for example ensure that your transaction was not part of a stale block.

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#1947

When two miners solve a block at the same time, both blocks will have a copy of the block until another miner comes along and verifies the true block. The longer block will win and a validated block will be created within 10 minutes.

A stale block is when the current block was not validated meaning that those transactions return to the mempool.

A stale block occurs because two blocks were created at the same time, until one block becomes validated or longer than the other block. The shortest block will be dropped.

It is important to wait for 6 confirmations because you need to ensure that this is the true block created and not a stale block.

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#1948

When miners solve a block at the same time, the longest block will win and the other dropped with its transactions returning to the mempool.

A stale block is an orphaned block.

It is important to wait for all the transactions to fully propagate throughout the blockchain network.

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