Homework on Stale Blocks

Blockchain and Bitcoin 101
#1464
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Then there can be 2 Versions of Valid blocks for some time. But the chain with most POW wins and this chain gets propagated.
  2. What is a stale block?
    A stale block is a block that is valid, but Unconfirmed and does not get propagated because a other chain has more POW.
  3. How do stale blocks occur?
    When 2 miners find a valid block at the same time at a other location. Then it can happen that for a short time there will be 2 Versions of truth.
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    When you wait for approx. 6 Confirmations, then you can be sure the transaction is confirmed.
    Blocktime should be approx. 10 minute.
    When you donā€™t wait, the transaction is not confirmed yet.
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#1465
  1. When 2 miners solve a block at the same time the block in the longest chain wins and the other block is a orphaned block.
  2. A block that was dropped from the blockchain due to an occurrence of a fork.
  3. When two miners mine a valid block approximately at the same time.
  4. In case of the occurrence of two chains, once one chain is accepted as the main chain, and the other is orphaned.
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#1466

Homework on Stale Blocks - Questions, July 20th 2020

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

This will cause one of the miners block not link onto another block it will become a stale block and is rejected by the network. That minerā€™s blockchain is short in length compared to the rest of the blockchain on the network. The network will always choose the longest blockchain as the valid blockchain. If the other minerā€™s block is linked on the longer blockchain, it will not be rejected, and will remain on the blockchain.

  1. What is a stale block?

Stale blocks are blockchains rejected by the network.

  1. How do state blocks occur?

The blockchain is rejected because it was out competed(out numbered) in length of the blockchain compared to the rest of the database on the network.

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

Itā€™s important to wait for more than one block to confirmed because this eliminates the conflict of stale blocks, and gives the network enough time to confirm and update the blockchain.

-Hector A. Martinez

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#1467

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Then 2 versions of the blockchain will be created, the version that can append new blocks the fastest will eventually be used.

  2. What is a stale block?
    A well-performed block, but not part of the well-formed (longest) chain.

  3. How do stale blocks occur?
    When a block is verified it gets propagated to the network. If 2 blocks get propagated at the same time, 2 chains will occur. One of these chains will be rejected and the blocks added to 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?
    To make sure your transaction will not end up in a stale block.

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#1468

When a stale block occurs, both get appended to the blockchain and miners continue mining on either one of them. Eventually one of the blocks will have more PoW and the other one will become stale.
The reason a user has to wait for 6 confirmations (or 6 blocks to get mined) is because of the probability of a stale block and the transaction being included within it :slight_smile:

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#1469

What do you mean? Both blocks are considered valid when mined.

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#1470

Blocks that have more PoW donā€™t necessarily contain more block rewards and fees :slight_smile: maybe one block in the after the stale blocks are dropped is only half full and doesnā€™t contain many fees :slight_smile:

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#1471

But a block gets added as soon as its mined. What would an occurrence of a stale block mean from the perspective of the user?

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#1472

[quote=ā€œivan, post:1, topic:8434ā€]

  • What happens in the bitcoin network when two miners solve a block at the same time?
    They are both added to blockchain however the chain is now forked. The next block to be added will decided which block gets dropped.

  • What is a stale block?
    A stale block was once a confirmed block that was added to the blockchain, but that was later dropped or removed from the blockchain and sent back to the Mempool.

  • How do stale blocks occur?
    If the mining gets too fast, the chance to get stale blocks increases.

  • Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    To make sure that your transaction is not in the stale block that will eventually be dropped.

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#1473

Thank you fod read the post ,and thank you for your help in this topic. Iā€™m really appreciate.

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#1474
  1. Nothing realy, till is joined next block to one of compeeting blocks, rest of them are discarded
  2. Orphan block was valid block, unfortunately discarded due presece in shorter version of blockchain
  3. Due acceptance of longer version of chain.
  4. Is need to wait till is clear that whole network is fully synced and this particular tx is not in orphan block
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#1475

wait 6 confirm. if in case stale block occur

#1476

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    They cause conflicts on the network which result in the production of stale blocks

  2. What is a stale block? A stale block is a block with unspent transactions which is not part of the best blockchain because they are overridden by a longer chain.

  3. How do stale blocks occur?
    When two blockchains are geographically distanced from one another, they could propagate their blocks to other nearby nodes and thus will be competing. Once this occurs, the blockchain that is the longest will be considered the most correct and will override the shorter one.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    The more confirmation we get from other nodes, the more secure the transactions becomes as more nodes are in agreement. Six confirmations are usually considered safe.

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#1477

  1. What happens in the bitcoin network when two miners solve a block at the same time?
    Both versions of the blockchain spreads on the network from each respective miner. Itā€™s then up to the global mining community what happens. Whichever of the two different blocks that most new blocks are mined on gets to stay in the permanent blockchain. The block that comes in second in this race is then discarded as a stale or orphaned block.

  2. What is a stale block?
    Itā€™s a technically complete and finalized new block, thatā€™s been out competed by another, longer, continuous blockchain. So the stale block, then falls out of the blockchain and all its transactions is returned to the mempool.

  3. How do stale blocks occur?
    See no. 2.

  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
    Itā€™s common to wait for six blocks so the risk of the block turning stale gets reduced enough. After six blocks itā€™s basically safe to trust on the block not turning stale.

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#1478

#1if 2 miners are competing for last block it ends up being 3rd miner deciding by chance and the one block will be put in the mempool ā€¦

#2stale block is a dropā€™t block returns to mempool

#3stale blocks occur by being quickly produced

#4confirmed transaction should be 6 blocks or more to be sure it was used in blockchain less then 6 it could be dropā€™t sent back to mempool ā€¦

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#1479

1- the network keeps the two versions of the true until a miner adds a new block and the network will reject the stale block.
2- is a block rejected by the network.
3- occur when two miners solve the nonce at same time and we get two versions of the network,when one of the versions gets one more block the other version gets rejected.
4- Because hour transaction could be on the rejected block.

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#1480
  1. The network still accepts it but will drop the shorter chain eventually.
  2. A stale block is a shorter chain that has to be dropped by the network.
  3. Stale blocks occur when there are two blocks produced at the same time. And when the other chain gets more block by chance, the shorter chain will be invalidated.
  4. So that invalidation of chains/stale blocks will be prevented.
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#1481
  1. What happens in the bitcoin network when two miners solve a block at the same time?

Both blocks start to spread out through the network. Which block that the network will continue on depends on the following mined block.
Let say that two miners solve a block at the same time - Block A and Block B
If the next mined block is linked to Block B, Block A gets dropped ā€œstale blockā€ and the network will accept Block Bā€™s chain, because it is the longest chain.

  1. What is a stale block?

A dropped block. (Block A in the example in question 1.)

  1. How do stale blocks occur?

They occur after two or more miners solve a block at the same time. The stale block is the block that was not part of the longest chain in the end.

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

To make sure that your ā€œconfirmedā€ TX donā€™t get dropped into the mempool again if the block that confirmed your TX happened to be a stale block.

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#1482
  1. What happens in the bitcoin network when two miners solve a block at the same time?
    They are accepted at their most local nodes both attach to the previous block, afterwards forming a mini-fork depending on which block is added to more speedily afterwards will ascertain the chain length and the shorter chain is dropped
  2. What is a stale block?
    A block that is part of the shorter and unsuccessful chain is dropped and returned to the mempool
  3. How do stale blocks occur?
    similar answer to Q1, the protocol is the shorter chain is dropped and to be the shorter chain you need to have a longer chain developed, at this moment when the protocol says yes you are the longest chain Mr Short is dropped and its attached lesser blocks, these blocks and their transfers TX within are now stale or orphanedā€¦
  4. Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?

Your transaction could be part of a dropped shorter chain and apparently waiting for 6 confirmations means that your block is part of the successful chain and will not be dropped

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#1483

  1. When 2 miners solve a block at the same time, there exists 2 separate blockchains, each with their own version of the truth.

  2. A stale block is a result of a freshly mined block being abandoned by the chain with the most proof of work (PoW).

  3. As mentioned earlier, there can exist 2 separate versions of the blockchain. When this problem is resolved, by miners commiting to one of these versions of the blockchain, blocks from the other version of the blockchain are left behind; they become stale. Sometimes the terminology ā€˜orphaned blockā€™ is used, and while they are technically different, they are used with the same connotations.

  4. Because of this transitive state where multiple versions of the blockchain can co-exist, it is highly beneficial (perhaps necessary) that a particular transaction is not executed entirely until at least 6 subsequent transactions are validated. Then one can be almost 100% sure that the version of the blockchain with your transaction on it will remain valid and not become stale.

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