blockchain / LEVEL 4

The free mempool replacement

EST.45 MIN

THEORY / RETRIEVAL

What to restore

Index replaceable transactions by sender and nonce
Require a deterministic minimum fee bump
Handle duplicate ids and fee arithmetic overflow

The mempool is policy, not consensus

Nodes may choose different admission, eviction and replacement policies while validating the same blocks. A replacement normally targets the same sender/nonce slot and must pay a meaningful bump to prevent cheap gossip churn.

Nonce order creates dependency chains

A high-fee future transaction cannot execute while an earlier nonce is missing. Selection must reason about executable packages, per-account limits, total bytes and adversarial transactions rather than globally sorting isolated fee values.

CHECKPOINT

Why is sorting every transaction only by fee insufficient for an account-nonce mempool?

Confidence: 3/5

02 / IMPLEMENTATION

Implement the contract

Implement one mempool replacement slot per (sender, nonce). A replacement needs at least ceil(old max_fee × 110%), with a minimum bump of one. Duplicate tx_id is Duplicate; threshold overflow makes the old transaction non-replaceable.

Initializing editor…

CLOUD SANDBOXnetwork off · 256 MB · 12 s

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OUTPUT

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