Shard Scheduler: object placement and migration in sharded account-based blockchains
This addresses scalability and efficiency issues for blockchain developers and users by optimizing shard management, though it appears incremental as it builds on existing sharding concepts with specific improvements.
The paper tackles the problem of object placement and migration in sharded account-based blockchains to reduce cross-shard transactions and improve throughput, achieving a 50% reduction in cross-shard transactions, a 3-fold throughput increase with 60 shards, and a 70% latency reduction with 10 shards in evaluations.
We propose Shard Scheduler, a system for object placement and migration in account-based sharded blockchains. Our system calculates optimal placement and decides of object migrations across shards and supports complex multi-account transactions caused by smart contracts. Placement and migration decisions made by Shard Scheduler are fully deterministic, verifiable, and can be made part of the consensus protocol. Shard Scheduler reduces the number of costly cross-shard transactions, ensures balanced load distribution and maximizes the number of processed transactions for the blockchain as a whole. It leverages a novel incentive model motivating miners to maximize the global throughput of the entire blockchain rather than the throughput of a specific shard. Shard Scheduler reduces the number of costly cross-shard transactions by half in our simulations, ensuring equal load and increasing the throughput 3 fold when using 60 shards. We also implement and evaluate Shard Scheduler on Chainspace, more than doubling its throughput and reducing user-perceived latency by 70% when using 10 shards.