State Sharding

Overview

State sharding distributes account, contract, or object state among multiple partitions. Transactions touching one partition can be processed locally, while operations spanning partitions require authenticated cross-shard coordination.

The protocol must define how state keys map to shards, how validators are assigned, how proofs move between shards, and how load is rebalanced. Reassigning a shard also requires securely transferring or reconstructing its current state. Reducing per-node storage and execution can improve scalability, but state access becomes more complex. Hot accounts can create uneven load, and asynchronous cross-shard messages can weaken immediate composability. Designers must protect each shard from committee capture and data loss. Sharding state does not eliminate the need for a globally coherent ownership and finality model. State Sharding should be analyzed by separating data publication, commitment, sampling or retrieval, reconstruction, and final settlement. In State Sharding implementations, a commitment can authenticate data without ensuring that users or validators can obtain enough of it to verify state or produce an exit.

Committee-based, peer-to-peer, and base-layer publication models expose different trust and liveness boundaries. Risk exposure depends on encoding rules, sampling assumptions, participant distribution, withholding resistance, and the party that declares data available. Applications relying on State Sharding should identify how missing data is detected, how long data is retained, and what recovery path exists when normal providers fail. A rollup or shard can continue producing commitments while users remain unable to reconstruct the information required for independent verification. Capacity claims should be based on deployed parameters rather than projected roadmap throughput. Operational monitoring should track publication delay, sampling success, reconstruction failures, provider diversity, and the relationship between availability evidence and canonical settlement.