Homework on Mempool - Questions

Blockchain and Bitcoin 101
#3711
  1. What is the mempool?

A mempool is an intermediate temporary memory where user transactions are momentarily stored. Once the transaction arrives at this place, the miners select them to process them. It is at this last point, when the transaction really becomes effective and becomes integrated into the blockchain.

Bearing this in mind, we can say that mempool is a “waiting room”. One in which the transactions are stored until they are processed by the miners.

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

The mempool will be crowded and this will imply that will take more time for the process of confirm transactions.

  1. How does a growing mempool effect transaction fees?

The fewer transactions in the mempool, the less pressure on the network and the faster the confirmations. This is why when a mempool is “full,” confirmations usually take longer.

The resolution of the transactions by the miners is very fast. However, miners will take longer to confirm their transaction if the mempool is crowded. This situation leads users to pay more commissions in order to take a higher priority for miners. The higher the commission, the greater the probability of being quickly chosen to process your transaction. A competitive situation that we can see markedly in the rise in commission prices when the mempools are at their limits.

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#3712

Block difficulty doesn’t get reduced because there are more pending txs. It only adjusts based on the network hash rate. :slight_smile:

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#3713
  1. What is the mempool? A mempool is a list of unconfirmed transactions that have been broadcasted by nodes are stored until a miner puts them into a block.
  2. What happens if the miners can’t keep up with the rate of the new transaction? The unconfirmed transactions will accumulate, and the mempool becomes larger.
  3. How does a growing mempool effect transaction fees? Transactions in the mempool with the highest fees (sat/byte) will be chosen by the miners to be put into the new block. Therefore new transactions will select higher fees in order to make it process faster.
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#3714

  1. the mempool is a storage pool for all the unconfirmed transactions in the network awaiting confirmation.

  2. if miners cant keep up with the rate of transactions the mempool will grow, there will be more transactions that need to be confirmed

  3. as the mempool increases the transaction fees increase, miners choose transactions with higher fees to add to the blockchain

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#3716

Is the network hash rate adjusted automatically after certain amount of pending tx-s is reached?

#3717

Mempool is a copy of unconfirmed transaction list that each node has.
If the miners cannot keep up with the rate of new transactions, mempool gets bigger and the network hash rate gets adjusted.
Transaction fees grow.

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#3718
  1. What is the mempool?
  • The place where unconfirmed transactions are waiting for confirmation.
  1. What happens if the miners can’t keep up with the rate of the new transaction?
  • The mempool’s size will grow, a confirmation will take more time at higher fees.
  1. How does a growing mempool effect transaction fees?
  • Fees will grow.
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#3719
  1. mempool is a base of stored unconfirmed tx not yet part of a block.
  2. the mempool gets bigger.
  3. the tx fees increase.
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#3720

  1. Mempool contains the unconfirmed transactions, each node has its own Mempool

  2. Mempool will grow in size which would mean the miners will have more transactions to confirm, thus a longer time for a transaction to be confirmed

  3. If the size of the mempool increases, the placement of transaction fees will be more competitive thus higher fees to have your transaction processes first

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#3721

To clarify, I think I was getting a bit confused by some previous information I learned outside of the course. The block difficulty is not reduced, but nodes on the mempool add limits to new transactions as the mempool fills.

Looking a little deeper into the mempools functionality, as the number of pending transactions increases past the miner’s capabilities, they introduce a minimum fee and remove transactions lower than that minimum fee from the pool.

Miners prioritize transactions that are more complex first given they’re paid satoshis/byte; more bytes equals higher fees.

The network target is adjusted based on network hash power, but that is part of Proof of Work and not the mempool.

Is this correct?

I appreciate the feedback.

#3722

  1. The mempool is a list of transactions that have been verified by nodes but not yet confirmed by miners.

  2. In this scenario, the miners simply prioritize transactions with higher fees.

  3. Transactions must have higher fees in order to be confirmed sooner.

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#3723
  1. What is the mempool?
    The transaction in a mempool is an unconfirmed transaction waiting to be picked up by a miner to be confirmed. Nodes and miners both have mempools to store tx-s.
  2. What happens if the miners can’t keep up with the rate of the new transaction?
    The miners will pick up the tx with the highest fee. The fee is calculated by bytes, not by BTC. All the other tx-s with a smaller fee will stay in a mempool.
  3. How does a growing mempool affect transaction fees?
    Growing mempool will affect the price of the fees. You would have to adjust the height of the fees to compete for a faster tx.
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#3724
  1. What is the mempool?
    Pool full of unconfirmed transactions waiting for miners to pick and confirm them so they can be inserted in the blockchain.
  2. What happens if the miners can’t keep up with the rate of the new transaction?
    The transactions are chosen from the highest to lowest fees, if the miners cannot keep up the transaction will be inserted in a new block.
  3. How does a growing mempool effect transaction fees?
    Because the fees are calculated based on the size of the information, not in the value.
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#3725

No, the hash rate gets adjusted every 2016 blocks, or approximately every 14 days. Pending tx have nothing to do with it.

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#3726

Yes by default miners usually store up to 300MB of txs in the mempool and drop the ones that are older than 14 days. But this is just a config in the bitcoin core implementation, not part of the protocol, and can be changed by the user.
Theoretically the mempool can be infinite in size. :slight_smile:

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#3727

  1. What is the mempool?
    A pool of unconfirmed transactions waiting to be picked up by miners.

  2. What happens if the miners can’t keep up with the rate of the new transaction?
    The transaction with the highest fee will be picked up by the miners first. In the meantime the mempool gets larger.

  3. How does a growing mempool effect transaction fees?
    A growing mempool leads to the block difficulty being reduced. This gives miners the chance to have higher transaction fees.

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#3728
  1. Stores unconfirmed transactions.
  2. Increases mempool size.
  3. Increases fees.
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#3729
  • The mempool is a place where unconfirmed transactions wait for a miner to pick them up to add to the next block.
  • If the miners can’t keep up with the rate then the mempool grows larger and there are longer transaction times.
    3.Transaction fees increase with a larger mempool because of the competition to get the transaction to the next block. Larger fees are offered to miners to get the transaction picked first
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#3730

  1. What is the mempool?
    A pool of unconfirmed transactions stored on all nodes, awaiting collection by miners to admit to a new block, to become confirmed.

  2. What happens if the miners can’t keep up with the rate of the new transaction?
    In this case the mempool grows larger and transaction times increase.

  3. How does a growing mempool effect transaction fees?
    It will increase transaction fees as the mempool can also be seen as a ‘fee market’, miners are out to make money so will cherry pick transactions with higher fees and or lower data to process, therefore a growing pool will lead to higher fees in order to get more transactions admitted and confirmed. Basically supply v demand mechanics.

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#3731

  1. The mempool is a database (of sorts) that contains all of the current unconfirmed transactions. Although the nodes will have verified these transactions so as to confirm that they are line with the blockchain, the transactions will remain unconfirmed until a miner includes them in a block. Indeed, miners will select transactions directly from the mempool and will prioritise those which have the highest TX fees.

  2. If the miners can’t keep up with the rate of new transactions, they will focus solely on the transactions which contain the highest fees. This will in turn increase the fees for subsequent transactions which have yet to be broadcast to the network. On the flip side, the increasing fees could encourage newcomers to start mining, thereby increasing the speed at which the global pool of miners could “process” the unconfirmed transactions.

  3. A growing mempool affects transaction fees by increasing them. Ultimately, if the mempool is “overcrowded”, BTC senders will have to increase the TX fee if they want their TX to be picked up by a miner sooner rather than later. If the sender only includes a small fee, the TX will not be picked up quickly and could actually become stuck in the mempool (temporarily).

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