Homework on Stale Blocks

Blockchain and Bitcoin 101
#1949

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

If two miner find a block at around the same time, it would result in a temporary split of the blockchain.
Since both blocks are deemed valid by the consensus mechanism, this split would occur because of the time it takes to propagate that block to all nodes.

( Some nodes will receive block A first and other would receive B first )

2. What is a stale block?

A “Stale” or “Orphaned” block is a block that once was valid and connected to the blockchain but later dropped due to the temporary split resulted from two miners finding a block at the same time.

3. How do stale blocks occur?

Stale blocks occur when 2 versions of a valid blockchain are converging back into one chain.

The transactions present in the stale block but NOT present in the Block on the longest chain will be send 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 it takes a few blocks to fully confirm that the block that holds the transaction you send or received will not be dropped and become a “Stale Block”.

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#1950
  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 the block eventually the longest chain will be placed on the blockchain and the other block becomes a stale block (interchangeable Orphan Block) . The transactions within the Stale Block are returned to the mempool.

  1. What is a stale block? A block of transactions that were in the shortest competing block and will be placed into the mempool.

  2. How do stale blocks occur? When two different miners have 2 different versions of the truth, and one miner eventually wins when they achieve the longest block.

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

In case of your transaction are dropped and placed in the mempool, typically you want 6 blocks confirmed on the blockchain, approximately 60 minutes in time.

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#1951

1/2/3. Both blocks get added by different nodes temporarily to their version of the bockchain, but one becomes an orphaned/stale block by that version of the chain getting rejected by the network. Which of the versions should be the correct one gets decided more or less randomly by whether one or the other gets added another block first. The “longer” chain, the one on which most proof of work was used on becomes the true one, the other gets rejected and the added block becomes a stole one.

4.Because of above mentioned orphaned Blocks occurring. Since transactions may be included within a possible stale Block, it generally gets waited 6 Blocks for confirmation.

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#1952

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    They both await confirmations from other miners. The one with most wins.

  2. What is a stale block?
    Stale block is one block which has not received enough confirmations to be included in the network. It does not become valid.

  3. How do stale blocks occur?
    By chance more than 1 version of a block will be produced.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To assure your transaction will be included in the validated block and not in a stale block.

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#1953
  1. There will be two different versions of the blockchain for a short amount of time.
  2. A stale block is a block which got discarded because another version of the blockchain was longer.
  3. Stale blocks occur when another version of the blockchain was chosen as the right one because of its length.
  4. It is important to wait for a few confirmations because the block with the desired transaction could be staled / dropped.
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#1954

A transaction propagates before it gets into a block. But once its confirmed there is still a possibility it might get dropped due to a block becoming stale. So a rule of thumb to wait a few confirmations is recommended. :slight_smile:

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#1955

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    When two miners find the nonce for the block at the same time, a accidental fork happens. This means that there is a split in the blockchain. Some of the nodes will have implemented one of the blocks and some of the nodes implemented the other.

  2. What is a stale block?
    A stale block is the blocks that get dropped from the blockchain during a fork. Then those transactions are getting sent back to the mempool

  3. How do stale blocks occur?
    When the blockchain gets 2 versions of the truth and a fork happens then the blockchain will always pick the longest version of the blockchain. One version of the truth will always be dropped. That is the stale block.

  4. Why is it important to wait for more than one block to be confirmed when sending a recieving a transaction?
    It is important to wait usually around 6 blocks to or the block to actually be confirmed when sending or recieving a transaction is because your block might get dropped. The blockchain usually will drop the blocks and send them back to the mempool after the 6 blocks have been confirmed after. This will only happen if an accidental fork happens.

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#1956

1. What happens in the bitcoin network when two miners solve a block at the same time?
a fork happens and lasts until one of them get a minimum of 6 child block, then the shorter chain will be dropped back to mempool.

2. What is a stale block?
Those blocks that got dropped back to mempool.

3. How do stale blocks occur?
stale block occur when a longer chain resolves the fork issue.

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a
transaction?
to make sure this block is on the valid chain and won’t end up as stale.

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#1957
  1. When 2 miners solve a block at the same time the block in the longest chain wins and the other block is discarded and considered a stale or orphaned block. All the transactions are returned to the mempool.
  2. A stale block is the block that was in the blockchain but then dropped because another block that was produced at the same time was part of a longer chain.
  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 for 6 confirmations to be sure that the block your transactions are in is not dropped from the chain.
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#1958

  1. When two bitcoin miners solve a block simultaneously, they both propagate their blocks to the network. The nodes geographically closest to each miner continue propagating their version of the blockchain, which they believe to be true, throughout the network. The network now has a split chain. Once the next miner upends their block to the blockchain, whichever chain that miner chose of the split becomes the true chain and the other block is dropped.

  2. Stale blocks are the blocks that were in the blockchain at one time but then were dropped because there’s another version of the blockchain which is longer, and it isn’t in it.

  3. It’s important to wait for more than one block to be confirmed when sending or receiving a tx because the block containing your tx in it could still be dropped.

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#1959
  1. Those blocks start competing to become the largest blockchain, the block the next miner picks will become the main blockchain making the other block a stale block.
  2. A stale block is a block that was dropped from the main blockchain.
  3. A stale block occurs when a miner chooses a block over the other.
  4. Because stale blocks can occur and by waiting 10 mins you can be sure your TX goes through all the way.
#1960

depends which block miners will include in proposal of new block, other will become stale block

Block that was propagated by the network but at the end was not included in blockchain

When block are mined at same time

because your transaction might have ended in stale block

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#1961

Waiting 10 minutes would probably result in one more confirmation. Each new block means a confirmation and since blocks are mined every 10 minutes, 6 confirmations will occur after about an hour. :slight_smile:

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#1962
  1. When two miners solve a different block at the same time, this creates a split in the chain of the bitcoin network. Whichever of these two blocks the next miner uses in the next block that is solved is considered to be the valid or the true block. The losing block or the one the the next winning miner does not use the next block is considered a stale or orphaned block and all tx’s are returned to the mempool to be included in the tx’s of future blocks.
  2. The losing block or the one that is not chosen in the next blocks to be the valid or true block is called a stale or orphaned block and all tx’s within it are returned to the mempool to be included in future blocks unless already included in the winning block which is possible as all tx’s are selected from the same mempool and mostly chosen based on the fees.
  3. Stale blocks occur when two miners solve a block at the same time. Whichever of these two blocks that is not selected or included in the next block in the chain has lost the tie and is considered or called a stale or orphaned block.
  4. As two blocks can be solved at the same time, a process of selection must be determined as to the true/valid block or the stale/orphaned block. This is why it is important to wait for up to 6 blocks aka 6 confirmations when sending or receiving a transaction, especially a very large one.
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#1963

1- there will be 2 versions of the chain temporarily
2- A stale block is a block that is discarded for a new and longest version of the blockchain with the most proof of work.
3-A stale block occur when theres 2 valid versions of the blockchain, and one of them gets discarded because of a longer chain with more Pow
4 This way we make sure that our block is not gonna be discarded

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#1964
  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, the miners propagate their own version of the newest block, with different transactions, to the closest nodes of them.
So it is possible that one part of all nodes has another version of the new block than the other.
In this case there are exist two latest versions of the blockchain at the same time.

  1. What is a stale block?
    If there are two versions of the blockchain at the same time, sometime a new block will be added to one of this two versions. A stale block is the latest block of the shorter version of the blockchain. Because the network only accept the longest PoW, the stale block will be removed and the transactions goes back to the mempool.

  2. How do stale blocks occur?
    They occur when one of two versions of the blockchain continue. The shorter one is not accepted and the latest block turn into a stale block.

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

Because it is possible that the block with your transaction will be a stale block and dropped.

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#1965
  1. What happens in the bitcoin network when two miners solve a block at the same time?

They start propagating their own new block, which is their own version of truth. Different miners will start mining from the different blockchain versions. The first miner that mines the next block on one of the blockchain version will be the one that will start propagating the longest version, and every node in the network that receives that version will accept it and propagate it. The transactions of the orphaned or staled block, that corresponds to the version of truth that has not been successful, will go to the mempool again, only if they have not been approved already in the successful blockchain.

  1. What is a stale block?

It is a block that has not been successful and is not agreed upon the network of nodes because there is another version of the blockchain that is longer.

  1. How do stale blocks occur?

There are blocks that are mined simultaneously in the network and different miners start mining on different versions of the blockchain. One of the miners will end up mining on one of the versions before the others, and will propagate its version of truth of the blockchain, which will be the successful one as it is the longest. The nodes will accept that version or the blockchain and they will discard the block of group of blocks that have not been successful. Those are stale or orphaned blocks. The transactions of the stale blocks will go to the mempool again if they have not been used in the other version of the blockchain.

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

Because it can be reverted for the reasons explained above.

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#1966
  1. It creates another chain , the longest chain will always win
  2. Dropped blocks, the shortest chain
  3. This occurs when an block is dropped, when one of the chains reaches six confirmations the other chain will drop
  4. To make sure that the chain has been accepted
#1967
  1. What happens in the bitcoin network when two miners solve a block at the same time?

If miners mine and two blocks are confirmed at exactly the same time and added to the network there is the possibility that for a short time there will be two versions of the truth on the chain creating a temporary fork in the blockchain.

  1. What is a stale block?

A stale block is a block that has been created as above and then been discarded from the network it has been discarded due to the fact that the blockchain will choose the longest blockchain due to its length, once this happens the discarded blocks transactions are returned to the mempool.

  1. How do stale blocks occur?

Stale blocks occur once a a new block has been created and the blockchain accepts the longer chain.

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

its important to wait six blocks to make sure that your transactions have been accepted into the block chain and not dropped from the chain in a stale block.

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#1968
  1. When 2 miners solve a block at the same time, both blocks are broadcast and added to the blockchain. This may cause a temporary fork in the chain, until it is established which particular chain is longer, and this chain will become the recognised one.
  2. A stale block (sometimes called an orphaned block), is a block that has been dropped from one part of a fork in the blockchain, due to this part of the chain being shorter and thus deemed invalid.
    3)Stale blocks occur when two blocks are ‘mined’ at the same time and both added to the blockchain, causing a temporary fork until it is established which part of the fork is longer (thus holds more credence), and the shorter part is dropped. The block(s) in this part are orphaned or stale blocks
  3. Waiting for more than one block to be confirmed when sending/recieving a transaction is important as the time delay allows for discrepencies between time zones to be synchronised, reducing the possibility of stale blocks being created, and thus reducing congestion on the network.
  4. Rock’n’roll will never die.
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