Homework on Stale Blocks

Blockchain and Bitcoin 101
#949

  1. Both versions of the blockchain are accepted and propagated throughout the network, until the next block is found, which will have only one of these versions in it. The other version of the blockchain one is then considered invalid.

  2. Stale or orphaned blocks are the blocks that got added in a blockchain that later was not continued, as described in 1. The transactions (UTXOs) in these stale blocks that haven’t been confirmed yet in the valid chain are then returned to the network’s mempools, and will be confirmed in the continued mining.

  3. They occur when blocks are mined at the same time but then end up being part of a invalid version of the blockchain, as described in 1.

  4. Because this drastically lowers the chances of the transaction being part of a block in a version of the blockchain that gets discontinued and declared invalid. The more blocks are confirmed and added after a certain transaction was confirmed, the higher the chance that the transaction will never be declared invalid / part of a stale block, as all the next blocks include this transaction as a immutable, essential part of the blockchain from then on forward.

#950
  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, there will be two versions of truth on the network.

  1. What is a stale block?

A stale block is a block which is no longer part of the current blockchain.

  1. How do stale blocks occur?

As there are two versions of truth on the network, only one can be appended even as both are valid. Newer nodes on the network continue to search and select the longer chain of the two before appending new blocks to it.

As such, the remaining blocks are no longer part of the current blockchain. They are deemed stale blocks after their version of truth is overridden by the longer chain. Their transactions are returned to the mempool to be picked up in a future block.

  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 more than one block to be confirmed when sending or receiving a transaction because there is greater certainty for the transaction to be validated. The transactions in the block of the longer chain are added and not discarded.

1 Like
#951

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

The one with the longest chain wins.

All transactions on the stale/orphaned block will go back to the mempool.

What is a stale block? / How do stale blocks occur?

It is when 2 miners mine a block at the exact same time thou only one can be appended to the blockchain and the other becomes stale.

After network consensus has been reached, the one with the shortest chain will become stale. All transactions within the stale block will head back to the mempool.

It is important to wait for more than one block to be confirmed to ensure that your block is used and not dropped from the blockchain.

Yes, the recommended time frame is 6 confirmations to ensure that the block is appended to the blockchain and has not become stale.

#952

  1. Both miners will propagate their blocks through the network at the same time, causing two versions of the chain. In the end, the chain which is the longest will win and blocks in the losing chain are then rejected and transactions are returned to the mempool.

  2. A stale block is a perfectly valid block which was on the blockchain for a period of time but was then later rejected as another version of the blockchain was longer without that block in it. The transactions within that stale block are then returned to the mempool.

  3. Stale blocks occur when there are two versions of the blockchain circulating throughout the network at the same point in time. The miners responsible for mining those blocks are competing against each other to append their block first, so essentially which ever block is appended first and the next miner chooses to mine off will be the version of the blockchain with the longest chain so that is the one that will be accepted as the single version of truth and the version that the stale block was on is rejected and that block becomes invalid and is known as the stale block.

  4. It is important to wait because of stale blocks. There is always a possibility that due to a time lag when propagating a block through the network that some other block was propagated faster and has already been appended to the chain and subsequent blocks are being mined based on that block. Due to this phenomenon, when sending or receiving a transaction it is important to wait for more than one block to be confirmed because that is confirmation in itself that the block containing the transaction has been validated by the network and is operating within the longest, most appropriate version of the blockchain.

#953
  1. There will be 2 blocks of truth and the following blocks will be competing in which block will be really confirmed and not be the stale block.
  2. A stale block is a block which was competing to another block because 2 blocks were solved at the same time, but the following blocks were appended to the other block so the block were the blocks were not appended to will drop and is called the stale block.
  3. If a 2 miners have solved a block at the same time and they spread the block to the nodes at the same time.
  4. Because your transaction might be in a stale block, this means that your transaction might be reversed and you have to wait for a longer period of time.
#954

  1. Each are attached to chain but the longest chain wins and gets appended to blockchain while the other one gets dropped.

  2. Stale Block is a block that was not part of longest chain and was discarded.

  3. When multiple miners solve the puzzle at same time. then the one whose puzzle is further solved as a next block gets appended to blockchain while the other one gets discarded, making it a stale block.

  4. To reduce probability of our block becoming a stale block.

#955

  1. Two different blockchains get propagated through the system (they are identical except the last block). This is called a fork.

  2. Stale or orphaned block is a block that was in a blockchain that got dropped. Its transactions get returned to the mempool.

  3. They occur when two or more blockchains (forks) are being propagated simultaneously. When one gets picked from the next miner to add the next block to it the other blockchain(s) will then get dropped. (the longest chain is the valid one; wins)

  4. It is important because the block with that transaction could become a stale block.

#956
  1. it creates a second blockchain
  2. dropped blocks that have been reverted back to the mempool
  3. if the block time is too slow or if there is a split in the chain and the longer chain has been accepted causing the blocks in the shorter chain to be dropped. thus creating stale or orphan blocks.
  4. because after 6 confirmation your tx is secure and the block cannot be dropped
#957

  1. a fork is created, two chains are mined independently, the longest one will win and will then be considered as the main chain.

  2. it is a block of the shortest chain due to a fork

  3. They occur when 2 blocks are mined in the same time in two different places of the network.

  4. It is important to wait in order to verify that our transaction has not been part of the stale block.

#958

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    There are two versions of the blockchain that get passed on to the nodes on the network.

  2. What is a stale block?
    A block that was part of the blockchain but no longer is.

  3. How do stale blocks occur?
    They occur by the other version of the blockchain being worked on at the same time by other nodes and one of those miners adding to that version. Then that version of the chain becomes longer so the consensus is that the longest chain continues to be worked on while the other version is dropped.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    So that we are certain that the block that was added continues to the be in the longest chain, thus not becoming stale and remain valid.

1 Like
#959

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

The longer blockchain will win out and the shorter one will be dropped and be returned to the mempool.

2. What is a stale block?

A block that was dropped because it was part of a shorter chain that temporarily forked off until the longer chain won out.

3. How do stale blocks occur?

Stale blocks occur when two miners solve a block at the same time without knowing of the existence of the other. The shorter chain becomes the stale block and is 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?

It is a best practice to wait for six confirmations so you know for sure you are on the longest chain and you are not part of a stale block.

1 Like
#960

What happens in the bitcoin network when two miners solve a block at the
same time?
The chain forks into 2 until one of the chains becomes longer which will become accepted as the continuation of the chain. The other fork will be discarded.

What is a stale block?
This was a valid block in the chain but was later discarded

How do stale blocks occur?
When a different for of the blockchain becomes longer and invalidates this one.

Why is it important to wait for more than one block to be confirmed when
sending or receiving a transaction?
To ensure the block with your transaction does not become stale.

1 Like
#961
  1. This creates two versions of the truth. A few minutes later one of these versions will be chosen by the upcoming blocks.
  2. The stale block is the version of the truth that was not chosen by the new block. The stale block gets sent to the mempool to wait in line again to be picked by a miner.
  3. Stale blocks occur when the chain splits because of two miners completing a block at the same time. One of these blocks will continue the chain when new blocks add on to it, meanwhile the other block that was not chosen by the new blocks will have less POW so it gets sent to the mempool. That is the stale block.
  4. That’s because when the block is deep in the chain by at least a few blocks, we know that it will not be changed. It is a confirmed transaction. That is why it is recommended to wait 10 min or a few blocks to make sure a transaction is confirmed.
1 Like
#962

Stale Blocks Homework

  1. When two miners solve a block at the same time both are valid, but sooner or later another miner will choose on over the other and that one will have longest blockchain with most PoW and this is the version of truth accepted. The one rejected will go to Mempool and be considered an orphan/ stale.
  2. A stale/ orphan block is the version of truth not accepted by the network; the transaction in a block that is dropped.
  3. Stale blocks occur when two miners propagate blocks through network at the same time and are valid, but one of them is removed and returned to the Mempool because it is shorter and rejected over a competing longer version of truth.
  4. It is important to wait for more than one block to be confirmed because it might be the case that your transaction is in a block that may be dropped. Waiting about ten minutes or six blocks allows new block to be validated.
1 Like
#963

  1. Both blocks will be sended to other nodes

  2. Then miners mine those blocks again, but only the block with the longest chain will be accepted. The other block will get dropped = this one is called stale block

  3. see 1. and 2. = when 2 miners mine the same block at the same time

  4. if you don´t wait for more confirmations, your transaction can be in a stale block and gets dropped.

1 Like
#964

  1. It will propagate the network and the first block to be re-mined upon will create the longest chain and will be accepted in to the chain- the longest chain wins

  2. A block that is not accepted into the chain by not being fast enough- these blocks will not push transactions that did not make it into winning block and the transactions will stay in the mempool.

  3. By being processed to slow and not being accepted into the network- by not being the part of the longest chain.

  4. To ensure your transaction has made it into a winning block chain- That the chain has been successfully accepted into the network across the world(you require 6 confirmations before it is finite).

#965

1. What happens in the bitcoin network when two miners solve a block at the same time?
There are basically two versions of the blockchain, and is needed a next block to define which chain will be the accepted one.
2. What is a stale block?
It is a block that has been discarded.
3. How do stale blocks occur?
It occurs when two or more miners mine a block at the same time and there are two (or more) chains, so then the chain with more pow is selected and the other one is discarded. The last block from the discarded chain is discarded too and receive the name of stale block
4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Because the probabilities that the block where your transaction is will be discarded are exponentially lower for each block that is added.

#966
  1. They both add it to the network, creating a fork.
  2. A stale block is the one dropped from the Blockchain.
  3. Stale blocks occur because they were not in the longest chain
  4. Because it may be dropped if its not confirmed by most of the network
#967
  1. Two are created!
  2. One that is dropped.
  3. Because they’re two blocks added at the same time.
  4. Because you wanna make sure that you’re block doesn’t get dropped and sent back to the dreaded mempool!
#968

  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 on the bitcoin network it creates a duplicate block.

  2. What is a stale block?
    A stale block or or orphan block is one of the duplicate blocks that are dropped when two miners solve a block a the same time.

  3. How do stale blocks occur?

A stale block occurs when two miners solve a block on the bitcoin network at the same time, and one of those duplicate blocks needs to be discarded to create a stale block.

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

This will allow you to confirm that none of the blocks in your transaction were stale, and assures that you are one the longest part of the block chain.