Changing the minimum relay feerate

The discussion revolves around a proposed change to Bitcoin Core, which suggests lowering the minimum relay feerate from 1000 satoshi per kilobyte (sat/kvB) to 100 satoshi per virtual byte (sat/vB), as detailed in a pull request on GitHub (see PR here). This proposal is partly driven by observations of transactions with fees below 1 sat/vB being successfully relayed and mined, alongside a specific pull request aimed at addressing these low-fee transactions within Bitcoin Core (related PR). The motivation for such adjustments stems from the recent trends indicating that blocks populated with many sub-1sat/vB transactions experience slower propagation across nodes, especially if those nodes had previously rejected or not received information about these transactions.

The text further elaborates on the importance of maintaining a balanced approach to avoid block relay issues while also preventing potential attackers from exploiting low transaction costs to overwhelm the network. The minimum relay feerate serves as a deterrent against denial-of-service (DoS) attacks by establishing a cost for bandwidth consumption across the tens of thousands of nodes involved in transaction verification and broadcast. Additionally, the concept of incremental relay feerate is introduced, highlighting its role in ensuring that replacement transactions contribute additional fees for the resources they consume, and in setting dynamic mempool minimum feerates to account for the costs of evicting existing transactions from the memory pool.

The discussion also touches upon the relationship between transaction fees and the real-world resources they represent, suggesting that fluctuations in Bitcoin's price in USD could be a factor worth considering when determining appropriate feerates. A specific rationale provided in another GitHub comment is referenced to underscore this point (view comment). The conversation invites further thoughts on how minimum feerates are utilized, the determination of an ideal minimum feerate, formalization of these concepts, and the implications for wallets and applications within the ecosystem.