Homework on Mempool - Questions

Blockchain and Bitcoin 101
#1507

Certainly :slight_smile: the nonce is basically just a random number that miners use to get the resulting hash below a certain threshold. Since hash is just a number like any other (just really large) and you want this number to be below this threshold you need to try multiple times until you get the right number.

You learned that a small change in input data drastically changes the output hash and we don’t want to change the important block data, a nonce is used instead. If the resulting hash is not below the threshold, the nonce is changed and tried again.

This process gets repeated until the desired output is achieved (this is what we call Proof of Work) :slight_smile:

#1508

Thanks for the input again. I love it!!!

So, the nonce is a number in the block right?
So the number from the nonce combined with the tx data in the block makes the block hash? and do they guess the number or the hash value?

#1509

Yes :slight_smile: they are guessing the hash value by changing the nonce each time.

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#1510
  1. Storage in nodes for unconfirmed transactions waiting to be queried by the miner.
  2. The mempool will grow as each block created by the miner is limited in size.
  3. The fees are higher to send a transaction if you want the transaction to be prioritzed and placed into a block ahead of other transactions.
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#1511

What is the mempool?
Bytes representing the transaction, held in memory of the data structure of full nodes on network, while in unconfirmed state.

What happens if the miners can’t keep up with the rate of the new transaction?
A delay in confirming transaction can occur (traffic jam), requiring multiple confirmation cycles before the transaction is confirmed, depending on how a given transaction is constructed and how large a fee is attached to the transaction (fee/byte ratio) for it to be prioritized or not by the miner, relative to competitive environment of fees available for miners at that time on the network. In a worse-case scenario, after about 48 hours if no confirmation has occurred the transaction is returned back to sender’s wallet. Some wallets have a feature that allows for replacement of fee with larger fee for a transaction already sent, for better confirmation results on network when needed due to congested network conditions.

How does a growing mempool effect transaction fees?
Fees increase because there’s more demand for confirmations and miners can require higher fees.

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#1512
  1. What is the mempool?

It’s a list or record of unconfirmed transactions (UTXOs). These transactions wait in the mempool till they’re picked up by a miner and added to a block on the blockchain. The transactions stays in the mempool till it receives enough confirmations to be added to the blockchain.

  1. What happens if the miners can’t keep up with the rate of new transactions?

The mempool will grow and it’ll result in longer transaction processing times and possibly larger fees.

  1. How does a growing mempool affect transaction fees?

It’ll most likely result in larger transaction fees and larger fees will be prioritised by the miners.

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#1513

  1. The mempool is the backlog of unconfirmed transactions that miners need to verify to add them to the blockchain.

  2. If the miners can’t keep up with the transaction rate, the mempool grows larger and transactions fees increase.

  3. A growing mempool results in a queue of transactions. The transactions that pay the highest fee will be prioritised by miners due to the financial incentive of them. Transactions with higher fees are not necessarily larger transactions. Fees are based on a satoshis per byte calculation, so if a transaction is small in value but complicated in its nature - e.g. many small transactions to many different addresses - the fee could end up being higher.

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#1514

Transactions stay unconfirmed while in the mempool, once a ty is mined in a blocks it becomes confirmed once and each subsequent block added after that block means one more confirmation :slight_smile:

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#1515

What is the mempool?

Mempool as memory pool, holds the unfirmed transacions that haven’t been picked up by miner yet. So the transactions doesn’t get to the blockchain it gets to the mempool then the nodes hold.

What happens if the miners can’t keep up with the rate of the new transaction?

Mempool swells up with txn amounts together with fees.

How does a growing mempool effect transaction fees?

At the challenge to get the txns confirmed and appending to the chain, amount of the txns does matter of size and makes the fees increase in swelled up mempool.

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#1516

  1. The place where all the transaction data that has not been confirmed sits and waits to be confirmed…

  2. They get put in the memo pool to wait to be confirmed.

  3. In increases the fees due to miners looking for the more profitable fees. ( I think :thinking:)

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#1517

What is the mempool?

Mempool is a “waiting spot” for each node, it maintains itself. When a tx have been verified by a node the tx waits inside the mempool until it’s picked up by a bitcoin miner and inserted into a block.

What happens if the miners can’t keep up with the rate of the new transaction?

The mempools increase in size.

How does a growing mempool effect transaction fees?

Users will be compete to get their transaction into the next block by including higher fees.

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#1518

  1. A collection of transactions

  2. Transactions with higher fees incentives the miners to put those transactions in the block before the others.

  3. The fees go up

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#1519
  • What is the mempool?

a mempool is the collection of unconfirmed transactions

  • What happens if the miners can’t keep up with the rate of the new transaction?

The transaction will be broadcasted in the next block

  • How does a growing mempool effect transaction fees?
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#1520

  1. Mempoo is the pool of unconfirmed transactions.

  2. The system slows down as they can only store so many transactions per block.

  3. The more the UTXO’s the higher the fees in sats/byte

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#1521

1.- it’s a database where transactions pending to be confirmed are.
2.- The mempool will accumulate the transactions, taking more time for transactions be confirmed.
3.- Fee will increase, since the bigger the transaction are (many inputs) the higher the fees will be.

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#1522

Yes, miners usually prefer txs with larger sat/byte ratio :slight_smile:

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#1523

Transactions are first broadcasted to the network and are not included in a block yet :slight_smile:

Did you forgot to answer the last question? :wink:

#1524

  1. What is the mempool?
    A mempool is a database with pending transactions that have been approved from the nodes and that eventually need to be confirmed and inserted in a block by a miner.

  2. What happens if the miners can’t keep up with the rate of the new transaction?
    In this case the mempool will grow by size and by transaction fees.

  3. How does a growing mempool effect transaction fees?
    A growing mempool will increase the transaction fees.

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#1525

!. A mempool is all the unconfirmed transactions in a network.

  1. If the miners can’t keep up with the transactions, the mempool grows and the transaction time take more time.

  2. When the mempool starts to grow the transactions with the largest fee will be chosen first by the miner. This will also make for longer waiting times for those with smaller fees.

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#1526

What is the mempool?
Mempool is a list of unconfirmed transaction

What happens if the miners can’t keep up with the rate of the new transaction
Gets bigger and longer wait

How does a growing mempool effect transaction fees
Higher fee

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