Homework on Mempool - Questions

Blockchain and Bitcoin 101
#223

I understand the miners will get the highest fee txs to mine, but i dont see how this will make miners mining faster. the tx number in the mempool is the same so they will take from the higher fees to lower fees no matter how high the fees are those tx will end and the low tx will be taken at the same rate speed. yes the lower fee tx will stay longer in the mempool but i don see how higher fees wiil make blockchain faster. maybe i dont get it…

#224

  1. What is the mempool?
    is the placed where unconfirmed transactions are put while they are picked up by a miner

  2. What happens if the miners can’t keep up with the rate of the new transaction?
    they will keep transactions and propagate them to other nodes until they are picked up for mining

  3. How does a growing mempool effect transaction fees?
    fees grow as the mempool becomes larger

#225

you are right, miners can’t mine faster. The mempool will grow with many unconfirmed transactions. so miners will pick transactions with the highest fee first until they have no more place in that block. Other transactions will stay longer in the mempool.
So higher fee’s won’t make it faster, but higher probability that miners will pick that transaction first. so when the network is very busy, and you use an extremely high fee, your Tx will probably be added in the next block.

#226

Homework on Mempool - Questions

  1. What is the mempool?

A mempool is a collection of unconfirmed transactions from which the miner will take transactions that he will add to a block.

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

The mempool will increase, resulting in longer transaction confirmation times and increased fees

  1. How does a growing mempool effect transaction fees?

People will increase their tx fees in the hope of getting their tx approved faster

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#227
  1. the mempool are the colloctive memory off all the transactions whit in the network
    2.the mempool grows in size?
    3.the growing mempool will take longer time to verify sencie the miners will allways choce the transactions whit the higher fees so they higher fees transactions will go in to the new block first
#228
  1. What is the mempool?
  • storage of unconfirmed transactions
  • new TXs added to the mempool is propagated to other nodes
  1. What happens if the miners can’t keep up with the rate of the new transaction?
  • the number of unconfirmed TXs in the mempool increases
  1. How does a growing mempool effect transaction fees?
  • the TXs still in the mempool had the lowest fees and were not choosen by the miner for inclusion in the new mined block
  • new TXs need to provide higher fees than the unconfirmed TXs still in the mempool.
#229
  1. List of unconfirmed transactions
  2. Mempool increases
  3. Fees go up
#230

The mempool is a list of unconfirmed transactions that is available to all full nodes.

If there are more than enough transactions in the mempool to fill a block, the transactions with the highest fees will be taken first. If your transaction pays out a low fee, and there are more than enough transactions to fill the block, the amount of time it takes to complete your transaction will increase until the miners select your transaction from the mempool to be confirmed.

The smaller the mempool, the lower the transaction fees, and vice versa.

#231

The mempool is the node’s holding area for all the pending transactions. Its where of all the already seen and unconfirmed transactions inform a decision to relay or not relay a new transaction. If miners can’t keep up, the mempool gets bigger and fees go up.

#232
  1. the mempool is a temporary holding place for unconfirmed transactions
  2. the mempool grows and some transactions may not get picked up for a while.
  3. transaction fees typically go up with a growing mempool
#233

1- it is a repository of all unconfirmed transactions waiting which have been validated by the nodes but still waiting to be added to the blockchain

2- the number of unconfirmed transactions will grow in the mempool.

3- Not sure how fees are set. Is it a/ an automated mechanism reglated by the network which increases fees in order to increase miner participation? or is it b/ something which each person decides manually when making a transaction in order to be prioritised by the miners?

#234

  1. Transactions “waiting area” that each full node maintains. After a node verifies a transaction, it waits inside the node till a miner picks it up to insert it into a block

  2. Mempool will grow and will start prioritizing transactions by setting up a minimal transaction fee threshold. Transactions with a fee lower than the threshold will be automatically removed from the mempool. This prevents nodes to crash due to overload of pending transactions on their mempool.

  3. As miners go after transaction with higher fees, and there’s an overload of transactions, prioritization will take place and minimal transaction fees will increase.

#235

  1. What is the mempool?
    A mempool is a place of storage for unconfirmed transactions that miners need to put into a block.

  2. What happens if the miners can’t keep up with the rate of the new transaction?
    If miners cannot keep up with the rate of new transactions the mempool increases and transaction can be delayed.

  3. How does a growing mempool effect transaction fees?
    An increase in the mempool will cause the price for transaction to increase, since miners have limited size in a block they will be competing for the most valuable transactions.

#236
  1. The mempool is a special place where the unconfirmed transactions are put waiting for miners to confirm them.
  2. Longer transaction time and transactions build up.
  3. fees increase.
#237
  1. A Mempool is where all unconfirmed transactions wait for a miner to include into the next block.
  2. The mempool will just increase in size due to more transactions taking place and still be unconfirmed.
  3. The fees will increase with the increase in mempool size, therefore creating competition between miners to validate and include the transaction into the next block.
#238
  1. What is the mempool?

The mempool is a list of all the unconfirmed transactions that are deemed reasonable and ready to then further process. These transactions are then distributed to each node of the network where they are retained until selected and incorporated into a new block. Miners select transactions based on fees paid and the data size and complexity of the transaction.

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

In this instance the mempool increases in size and transaction times are longer.

  1. How does a growing mempool effect transaction fees?

As the demand for transactions increase then so do the rates of fees as there is increased competition in the network to process transactions.

:blush:

#239

  1. The Mempool is a floating scratchpad of as-yet-unconfirmed transactions that are waiting to be confirmed into the next block. They have been okayed by the wallet software by checking UTXOs on the blockchain, and the fee has been calculated in-wallet considering the network at the time. Your wallet will determine if a TX is ‘kosher’, and will then add and save this to the nearest node’s ‘mempool’ - either your own, if you run one, or the nearest alternative. All nodes have a mempool of unconfirmed TX, and the information in the various mempools begins to proliferate over the network. The largest Mempools with the highest fees attached are the most attractive to miners, and are therefore prioritised. Miners can query the mempools [their own mempool or other mempools on the network] to calculate their mining value. All TX in mempools will be seen to, but some will be seen to faster than others, because of this ‘fee market’. Once a TX is confirmed into a new block, it is removed from all mempools.

  2. Unconfimed TX go back into mempools, and the network will slow if there is a backlog. Fees will also increase, and TX with higher fees will be prioritised by the miners. TX with lower fees are deprioritised and continue to build.

  3. The more TX in a mempool, the higher the fees for miners. Because the miners ‘cherry pick’ the mempool with the highest fees, clearing the backlog becomes incentivised as fees build up.

#240

If I read you right you’re asking what prevents a signed transaction in the mempool from being copied and re-submitted to the mempool as a double-spend attack after it has been absolved to a block on-chain?

Excellent question. That attack was not specifically covered in the course.

However I can extrapolate. The value stored in each input UTxO must be 100% spent by any transaction that unlocks it. The replay attack would fail because the target UTxO address would be empty after the first transaction. Its left up to the wallet that’s building the transaction to re-route “change” outputs to new addresses.

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#241
  1. The Mempool are all the unconfirmed transactions that are waiting to be picked up by the miners in the next 10 minute block.
  2. If the miners can’t keep up, there is a back log in the Mempool.
  3. The miners go after the transactions that pay the most per bit. You pay in satoshi’s per bit. Every 10 minutes the number of transactions in the Mempool go down.
#242

  1. What is the mempool?
    The mempool is a data structure that each node has, consisting of a list of unconfirmed transactions.

  2. What happens if the miners can’t keep up with the rate of the new transaction?
    The mempool will grow & transaction time will increase.

  3. How does a growing mempool effect transaction fees?
    It increases fees because the miner will be incentivised to pick the transactions with the higher fees & people will offer that to get a faster transaction.