Homework on Stale Blocks

[mattv]

Homework: Stale Blocks

1. main blockchain splits until miners pick select one version of the chain over the other to continuing processing blocks. longer chain / most POW chain proves to win and other version of the blockchain is now discarded and txs go back into mempool and await to be verified and logged into the new blockchain.
2. stale blocks are the blocks that were once recorded on version of the blockchain that was shorter and not chosen by the rest of the network. no longer valid. orphaned chain.
3. network of miners choose the different longer version of the blockchain therefore those blocks are discarded.
4. to make sure your txs are part of the longer and network verfied blockchain, and not orpaned.

[briPod]

1. What happens in the bitcoin network when two miners solve a block at the same time?
   the solved blocks are released into the chain as normal

2. What is a stale block?
   a valid block which has been solved recently, but does not appear in the longest version of the chain

3. How do stale blocks occur?
   when one of the two versions of the chain becomes longer, the shorter will be discarded. any recent unique blocks will become a stale block, as it is not in the longer, trusted version of the blockchain

4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
   your transaction may be part of a block which gets orphaned/becomes stale

[PLAYINSAM]

1. When 2 valid blocks are mined, they give the next miner who comes along a choice. and that mine picks one of the two blocks. And it becomes the chain, the other block becomes stale.
2. A stale block is one that has been left out of the chain because there was a longer one.
3. Because there was a longer valid chain that was appended to the blockchain.
4. To make sure that the block that has your transactions are safe in the block and stay on the block chain.

[MrHunk]

1. The longest chain wins and the other block is discarded and considered a stale or orphaned block.
2. The block of the shortest chain after a fork will be moved to the mempool.
3. A stale block happens when two separate blocks are appended to the blockchain at the same time.
   4.In order to avoid the stale block or orphaned blocks.

[SoloDragonGG]

not yet but i getting really close

[Alko89]

@Flightcrew

A block that was part of a chain of blocks chosen to be invalidated by the network due to a mining solving-collision with another chain of blocks containing one or many of the same transactions.

Yes, these two blocks may also contain some of the same transactions. But at the time there is no way of knowing, so miners continue to mine on a block they got first. Eventually one will get dropped due to miners making more PoW on the second block.

[Alko89]

@Zolee

This delay is important to reduce the stale blocks by giving time to the network to add blocks more or less one after another. If all the miners would add new block as soon as they solve them the number of stale blocks would high and the rework for these block would increase and miners would consume more energy and mining would be more expensive.

Miners don’t wait. As soon as they get a valid block they begin mining on it and its a race to which chain more PoW will be added.
The reason a user must wait a few confirmations is to be sure their tx is not part of a stale block

[Alko89]

@PLAYINSAM

they give the next miner who comes along a choice. and that mine picks one of the two blocks.

Hmmm, could be if the miner is picky. But it usually just picks the block that arrived to the miner first

[Alko89]

@MrHunk

A stale block happens when two separate blocks are appended to the blockchain at the same time.

At that time there is no way of knowing which block will become stale it is only once more PoW is done on one block the other one gets stale

[Flightcrew]

Thank you @Alko89 it is a simpler process than I thought.

[SheepBoss]

• 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, both blocks are propagated through the network and two blocks are added to the chain. The blockchain with the most proof of work will be accepted. Whichever block the next miner chooses to add his block to, the other becomes stale.

• What is a stale block?

A stale block was a confirmed block on the chain however it has been dropped because it belonged to a shorter chain. (Less POW)

• How do stale blocks occur?

See answer to Q1

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

We always wait for six more blocks because a block with transaction may be in a chain that is dropped.
Additionally another version of the blockchain may not have been propagated across all the nodes yet.

[SheepBoss]

Could someone explain something for me?

Orphaned and Stale Blocks, Block Time & Confirmations 4.00minutes into the video - Ivan explains that the new miner chooses which block to add his new block to. How does the miner choose which block or is the newly mined block assigned to a specific block based on surrounding nodes?

[Taran]

1. Both will be added to the blockchain, however eventually one of the two chains will prevail and the other block will be dropped causing a stale block.

2. A stale block is a valid block that was once added to the blockchain, mainly as an occurrence of two blocks being produced at once, however is dropped and discarded as the other chain prevails.

3. Stale blocks occur, as two blocks are propogated into the network both with their own versions of the truth, however the chain of information custody of blocks has continued on the other block (because the mining difficulty is higher and/or chain is longer)

4. To see if your transaction has been accepted into the network and it hasn’t been dis-confirmed as a result of being part of a stale block

[Reed]

1. When 2 miners solve blocks at the same time, both blocks are propagated to the network but which ever block gets another block added first becomes truth and the other is thrown out.
   2)Stale blocks are previously accepted blocks that get dropped because they are not a part of the longest chain
2. Stale blocks occur when 2 blocks are found at the same time by different miners and the next block gets added to the other block resulting in the stale block being dropped from the network.
3. It is important to wait for more than one confirmation when sending or receiving money to ensure your transaction wasn’t on a stale block and the other party cancels the transaction before it is added to another block

[alcalvillo]

1. The are both appended to the network and previous blockchain, but only one will continue on as the longest surviving block when chosen by next miner.
2. A stale block, or orphaned block is one that is dropped after being rejected as the shorter version on the blockchain. Its Tx’s return to the mempool.
3. See 2.
4. The rule of thumb is 10 mins per block creation. It is best to wait for more confirmations (i.e. 6) in order to avoid being part of the stale block

[nielvosloo]

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

Both blocks are added to the blockchain, creating a temporary split of the blockchain.
This split occurs at node level, meaning that the different nodes are group together
based on the block they received and added. This temporary split of the blockchain will
continue to exist until such time that there is a longer blockchain that will be used as
the truth. All of the blocks in the shorter blockchains will be discarded by the networks
and all transactions in these blocks will be returned to the mempool.

2. What is a stale block?

In the event of a temporary split as explained in point 1, a block on the blockchain becomes
a stale block when the version of the blockchain in which it exists is no longer the longest.
All of the blocks in the shorter blockchain version since the split are discarded, ergo. stale block.

3. How do stale blocks occur?

When the version of the blockchain in which it exists is no longer the longest blockchain. (see point 1)

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

Due to the unlikelihood of a blockchain split to occur, having at least 6 blocks appended to the
block that your transaction exists in, ensures a 99.999% probability that your transaction is
in the longest blockchain on the network, thus ensuring that your transaction is complete.

[Alko89]

@SheepBoss

How does the miner choose which block or is the newly mined block assigned to a specific block based on surrounding nodes?

It doesn’t. When a miner receives a block there is no way of knowing if there is a competing block in the network. It might be but hasn’t propagated to the node yet.
So what a miner does is that it accepts the block and immediately starts mining a new block based on the block it received. If in the meantime he receives a block from the network that has higher PoW it will drop the block it was currently mining on and start mining on the longer chain.

[Ingridharp]

What happens in the bitcoin network when two miners solve a block at the same time?
Both blocks are being propagated in the network and will be recieved in the network .
Nodes will recieve the block from the miner that is closest to him…llike one node is working in canada and another in China, the nodes around the miner in Canada will recieve the block from Canda sooner then the block from China… It may occur that an other miner in China appends the next block to the block of the miner in China … Then that blockchain is the longest ( with most proof of work) and therefor the one to follow .
The block from Canada will be removed, the transactions go back into the mempool.

The block removed is called a Stal block or orphaned block.
The Orphaned block/Stale block occured because the block was not continued by other blocks.

[Salvatore]

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 at the beginning the chain is split into two parts. After nodes and miners will decide on which chain to continue building the blocks and the longest chain with the most PoW will be confirmed and the other will just drop out. The transactions of the dropped block will go back to the mempool.

2. What is a stale block?
   A stale block is a block that is not confirmed by all the network.

3. How do stale blocks occur?
   A stale block is dropped from the network and its transactions will go 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?
   This is important as the more time one waits the more blocks will confirm the sending or receiving and your transaction will be more safe and secure and accepted by the whole network.

[porter]

1. The chain with the shortest amount of blocks will be dropped.

2. A stale block is a block in the chain that did not receive any blocks after it.

3. A stale block happens when a miner mines a block in the chain and it did not receive any blocks after it.

4. Too make sure it doesn’t end up as a stale block and become a dropped transaction.