What is a mempool in Ethereum?

The mempool refers to the set of in-memory data structures inside an Ethereum node that stores candidate transactions before they are mined. Geth calls it the “transaction pool”; Parity calls it the “transaction queue.” Regardless of the name, it is a pool of transactions sitting in memory waiting to be included in a block.

Why do blockchains need a mempool?

So blockchains need a mechanism to figure out the sequence of how transactions are written to the block. The mempool is the dynamic staging area in front of the blockchain that enables transaction ordering, transaction fee prioritization, and general block construction. The term itself —mempool— comes from Bitcoin.

What is a mempool & how does it work?

The Mempool is basically the node’s holding area for all the pending transactions. Each node has a different capacity for storing unconfirmed transactions. As a result, each node has its own version of the pending transactions. This explains the variety of Mempool sizes & transaction counts found in different sources. 2. Mempool Management

How to confirm a transaction from a mempool?

In order to be confirmed, a transaction from the mempool needs to be included in a block. The size of a block cannot exceed 4 million weight units (1 million vbytes) , and each transaction has its own weight depending on the type of transaction, the UTXOs it spends (inputs) and the addresses it sends to (outputs).