Account Migration across Blockchain Shards using Fine-tuned Lock Mechanism

Sharding is one of the most promising techniques for improving blockchain scalability. In blockchain state sharding, account migration across shards is crucial to the low ratio of cross-shard transactions and cross-shard workload balance. Through reviewing state-of-the-art protocols proposed to reconfigure blockchain shards via account shuffling, we find that account migration plays a significant role. From the literature, we only find a related work that utilizes the lock mechanism to realize account migration. We call this method the SOTA Lock, in which both the target account’s state and its associated transactions need to be locked when migrating this account between shards. Thereby, SOTA Lock causes a high makespan to the associated transactions. To address these challenges of account migration, we propose a dedicated Fine-tuned Lock protocol. Unlike SOTA Lock, Fine-tuned Lock enables real-time processing of the affected transactions during account migration. Thus, the makespan of associated transactions can be lowered. We implement Fine-tuned Lock protocol using an open-sourced blockchain testbed (i.e., BlockEmulator) and deploy it in Tencent cloud. The experimental results show that the proposed Fine-tuned Lock outperforms the SOTA Lock in terms of transaction makespan. For example, the transaction makespan of Fine-tuned Lock achieves around 30% the makespan of SOTA Lock.