Homework on Stale Blocks

Blockchain and Bitcoin 101
#1344
  1. In this case, two separate strands of blockchain are created temporarily.
  2. It’s the block on the shortest strand, which will eventually be dropped.
  3. They occur when two blocks are created around the same time, but more blocks get attached to the other chain.
  4. It’s important to ensure that your block is in a chain that’s the longest. Otherwise, the block will be dropped and all transactions contained in it returned to the mempool.
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#1345

Thank you for your input, it is good to know someone is looking at our home work and giving us the opportunity to correct our work :clap:

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#1346
  1. If two miners simultaneously solve a block, the block that’s first accepted by another miner becomes the valid block.
  2. A stale block is the block not accepted by miners because the other one simultaneously solved with it has been validated.
  3. Stale block occur when two miners propagate two blocks at the same time to their surrounding nodes. Because there can only be one version of the truth, one block is accepted and the other becomes stale.
  4. It is important to wait for some block confirmation to avoid the case of a stale block.
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#1347

1/ When two miners solve a block at the same time, both are true and the chain will fork. When the next block is added to only one of the previous two blocks, the longest chain will win and the other block will be orphaned (removed), and its transactions will be returned to the mempool.

2/ The stale block refers to the the discarded (or orphaned) block that was not used.

3/ Stale blocks occur when two blocks are created by two different miners at the same time. When the next block is added, the fork is resolved and the stale block is cancelled.

6/ The best practice is to wait for 6 confirmations in case the first confirmations come from a stale block

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#1348

From the users perspective, it is more important for his transaction to not be part of a stale block :slight_smile:

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#1349

You are very welcome! :smiley: We love to help out and keep an eye on our students :wink:

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#1350

Thanks for this clarification! :blush:

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#1351
  1. It propagates the block to the nodes simultaneously, which creates a fork with 2 versions of the blockchain.
  2. A stale block is a block that is dropped from the shortest version of the blockchain and put back in the mempool.
  3. They occur when one of the versions of the stale block becomes longer then the other with at least 6 confirmations.
  4. Because it gives time for the information to circulate through the network and all the nodes to get the information from the previous block before a new one arrives
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#1352

When two miners solve a block at the same time, there are two “truths” of the blockchain. Only the one that gets shared and blocks appended to it will ultimately last. The second block (called an orphaned block) will send its transaction list back to the mempool.

A stale block (AKA orphaned block) is a block that is appended to the blockchain that is no longer worked on. Stale blocks get removed from the blockchain and are no longer worked on.

Stale blocks occur when two or more miners find a block at the exact same time. When this happens, only one version of the blockchain will continue and the rest of the blocks will be discarded.

It’s recommended to wait for six blocks to be confirmed because the transaction may be sent back to the mempool if the block becomes orphaned.

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#1353
  1. When the next block will connect to one of these blocks, the longer chain will prevail and the other block will be discarded and the transactions will go back to the mempool.
  2. It is no longer part of the block chain, because the longer chain accepted as valid.
  3. When two miners solve a block at the same time.
  4. The one confirmation could be a stale block.
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#1354

How do stale blocks occur?
They can occur naturally when two miners produce blocks at similar times, or they can be caused by an attacker attempting to reverse transactions.

What happens in the bitcoin network when two miners solve a block at the same time?
If two miners solve the hash at precisely the same time, then the miner with more network connections to the bitcoin network or other criteria will get accepted by the network first. One will become accepted by the network and the other will be discarded.

What is a stale block?
Stale Blocks are blocks that are no longer part of the current best blockchain because they were overridden by a longer chain.

Why is it important to wait for more than one block to be confirmed when sending or receiving a transaction?
Prevent your transaction entering in a stale block.

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#1355
  1. What happens in the bitcoin network when two miners solve a block at the same time?

Both of the new blocks try to propagate to the other network nodes. Ultimately, only one of those two blocks will be added to the blockchain.

  1. What is a stale block?

A stale block is a valid bitcoin block that gets rejected by the bitcoin node network.

  1. How do stale blocks occur?

Stale blocks can occur when an alternative block gets added to the blockchain and then becomes the longest chain.

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

That transaction can end up in a stale block that gets rejected by the bitcoin network and is then resent to the mempool where it will wait to be added to another block.

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#1356
  1. 1 chain will eventually when it gets longer and propagates through the network cause the other chain to be dropped.
  2. a block from a version of the truth that was shorter.
  3. a stale block occurs after a fork is resolved with a longer chain.
  4. in case of stale blocks to prevent your transaction to be invalid.
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#1357
  1. Both blocks will be included in the blockchain.
  2. A slate block is a valid block BUT is not part of the longest blockchain, therefore the block will be “dropped” from the blockchain.
  3. If two miner produce two valid blocks at the same time, and a new block is added to the “newly created blocks” before the entire chain can propagated through the network. The slate block will be dropped from the shortest chain.
  4. It is recommended that you atleast wait for 6 confirmations, this will ensure that your block is part of the longest blockchain.
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#1358

Stale block is just the one being dropped, at the time the fork happens there is no way of knowing which one will it be.

Te reason why we wait for 6 confirmations is to be sure our tx is not part of a stale block :slight_smile:

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#1359

Both blocks are added to the blockchain and propagated through the network and for a period of time the network will have two versions of truth until the longest version of the blockchain is accepted by the network.

A stale block is a block dropped from the blockchain.

When a longer version of the blockchain is accepted by the network all other blocks from the shorter version of the blockchain are dropped becoming stale.

A transaction needs to wait for more than one block until the network confirms that is part of longest version of blockchain.

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#1360
  1. one block will be stale, chain splits into two
  2. block which was validated by few miners but then dropped because it wasnt accepted by all nodes
  3. when block is validated by few miners but this information is not distributed for all nodes because of physical limitations
  4. so the block is not dropped (stale)
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#1361

Not exactly. Two blocks are mined at the same time (and both validated), separated by distance and eventually one gets dropped.
If our transaction appears in a stale block in can return back in the mempool. So its recommended to wait a bit :slight_smile:

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#1362

An accidental fork happens when two (or more) miners create a block at the same time. While both blocks have the same block height, each block is composed of different transactions.

A stale block is a block that has been successfully mined but is not a part of the main (or the longest) chain. Stale blocks occur when an accidental fork happens as the miners will have to redirect their attention to the chain with the most hashing power.

When it comes to the confirmation of transactions, the best practice is to wait until the creation of six block as there is a possibility that your transaction is on an orphaned block/chain. If it is, your transaction will be sent back to the Mempool.

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#1363

  1. two different chains get formed, and they start spreading their own truth to the nearest nodes. At one point the longer chain wins.

  2. it is a valid block of the shorter chain that got dropped and moved back to the mempool.

  3. Stale blocks occur when two miners mine a new valid block at the same time.

  4. to be sure that the block with your tx will not get dropped.

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