Block Assembly & Mempool Policy

Why this module exists

Mining is not just hashing; it is also economic selection. The block you mine determines your fees and influences mempool dynamics.

1) Fee rate

The canonical heuristic is fee per byte:

feerate = fee / size

Higher feerate transactions get prioritized.

2) Dependencies

A transaction may spend outputs of another mempool transaction. Selection must ensure inputs are available at inclusion time.

3) Size limits

A block has a size budget. Adding a tx may exclude others. This is a knapsack-like problem; we use a greedy heuristic here.

4) Coinbase output

Coinbase mints subsidy + fees. It anchors the miner's reward.

What you will build

1. Greedy mempool selection by fee rate
2. Input-availability checks
3. Coinbase reward calculation

Key takeaways

• Block assembly is an optimization problem.
• Dependencies require careful ordering.
• Fee policy influences network behavior.