What Is the Mempool and How Does It Relate to Transaction Confirmation?
The mempool, short for memory pool, is a waiting area for unconfirmed transactions that have been broadcast to the network but not yet included in a block. Every full node maintains its own version of the mempool, storing transactions that it deems valid.
Miners select transactions from their mempool to construct a new block, prioritizing those with the highest fee rate. A transaction must be in a miner's mempool to have a chance of being confirmed.
If a transaction is dropped from all mempools, it will not be confirmed unless re-broadcast.
Glossar
Waiting Area
Location ⎊ The waiting area, formally known as the memory pool or mempool, is the distributed, temporary storage location where all unconfirmed, valid transactions reside after being broadcast to the network but before being selected for inclusion in a block.
Mempool
Propagation ⎊ The mempool, within cryptocurrency networks, functions as a temporary holding area for unconfirmed transactions awaiting inclusion in a block.
Full Node
Validation ⎊ A full node is a server or computer running the blockchain's core software, responsible for downloading the entire history of the ledger and independently verifying every transaction and block against the network's consensus rules.
Miners
Validation ⎊ Miners, within the cryptocurrency ecosystem, represent network participants who compete to bundle pending transactions into blocks, subsequently adding these blocks to the blockchain through computationally intensive processes.
Unconfirmed Transactions
Transaction ⎊ In cryptocurrency and decentralized finance (DeFi), a transaction's unconfirmed status signifies its submission to a network but not yet inclusion within a validated block.