Every node has their unique memory pool in which it tracks unconfirmed transactions. Use this tag for questions on how transactions enter and exit the mempool, how the mempool is delimited and other aspects of how it works.
Questions tagged [mempool]
251 questions
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How do transactions leave the memory pool?
How does my bitcoin core client know when to drop a transaction from the memory pool?
Is it as simple as a specific period of time?
inersha
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What is the minRelayTxFee?
What is the minRelayTxFee?
What is it used for, what's the default value and how does the value change?
Murch
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Do unconfirmed transactions expire after some time?
Sometimes confirmation process is very slow. I think that is because of the price of the fee. In that time, is it possible to cancel the unconfirmed transaction and re-send with higher transaction fee? Are there any expiry features? E.g. the…
zono
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How can an unconfirmed transaction be removed from the memory pool?
Using Bitcoind and Json-RPC, how can I remove an unconfirmed transaction from the memory pool?
The scenario being that I want to remove the unconfirmed transaction because it's not getting confirmed, and it's preventing me from sending new…
Flavien
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What happens to transactions in the mempool when their parent transaction expires?
I was just reading the Coin Metrics Newsletter #53, and it included a section about the recent mempool congestion. After mentioning transactions that got evicted due to the network's queue of unconfirmed transactions exceeding the default mempool…
Murch
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8
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What if the mempool exceeds 300 MB?
The bitcoin mempool size is at 108 MB and still climbing according to chain.so. It is slowly approaching 300 megabytes, which is said to be the mempool limit for BTC. What happens after 300 MB?
Number File
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What is the maximum size of the memory pool?
The memory pool holds unconfirmed transactions in RAM. It seems that memory pool storage could overflow if no block is solved for a very long time and many transactions are published within a short interval.
In browsing the source code, I found no…
Rich Apodaca
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How does it contribute to the Bitcoin network when I run a node with a bigger than default mempool?
Lately, when the blockspace demand outstrips the default mempool size and the dynamic minimum feerate of nodes rises above the minimum transaction feerate, I often see the suggestion to simply increase the size of my node’s mempool. If I increase my…
Murch
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How do I uniquely identify a transaction (to protect against malleability)?
Transactions I broadcast can be malleated by anyone watching the mempool (more info here).
This rules out using txid for transaction identification.
How can I identify my transactions to make sure they are tracked by my application, even if the txid…
bvpx
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Speeding up confirmation by double-spending a transaction stuck in mempool
In the context of no-fee transactions that can take a long time to get their first confirmation, is it possible to use raw transactions and double-spend the original transaction by broadcasting another transaction but this time including a miner…
ktorn
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DDOS attack via BRC-20 & ordinals on Bitcoin
Do we currently see a DDoS attack on Bitcoin as the mempool is flooded with low value transactions incl. BRC-20, ordinals etc. (where the transaction fee exceeds the transferred value)?
What can / should be done to stop that or is that against the…
BitcoinFanatic
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Is it possible to add a transaction input to a transaction in the mempool?
Is it possible to add an input to a transaction that is in the mempool?
For example, if someone is paying 1 BTC to their friend, I can get the raw hex data of this transaction from the mempool before it is mined.
I can then sign an unspent…
bvpx
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Why doesn't the protocol allow unconfirmed transactions to expire at a given height?
Transactions with low fees may remain in the mempool for as long as 14 days. This indeterminism is a source of confusion for users and wallets. It's not possible to cause a transaction in the mempool to expire (become invalid) at a certain time in…
Larry Ruane
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What is the purpose of indexing the mempool by these five criteria?
In the bitcoin source code in txmempool.h, a comment says that unconfirmed transactions are indexed by five criteria:
* mapTx is a boost::multi_index that sorts the mempool on 5 criteria:
* - transaction hash (txid)
* - witness-transaction hash…
Amir reza Riahi
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A question about CPFP relaying policy
Let's say I broadcast a transaction tx0 signaling RBF replaceability. Later on, send another transaction tx1 that spends the same inputs of tx0, but this time with higher fees.
In this case, tx0 is removed from mempool right? so what if then I try…
Burak
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