# OptChain: Optimal Transactions Placement for Scalable Blockchain Sharding

arXiv: https://arxiv.org/abs/2007.08596 · HTML: https://mlsanity.com/paper/2007.08596/

## Key facts

- Cited by 2 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 16 Jul 2020.

## Built on by (most cited first, 2 of 2)

- [Performance Evaluation, Optimization and Dynamic Decision in Blockchain Systems: A Recent Overview](https://mlsanity.com/paper/2211.15907/) (2022)
- [TxAllo: Dynamic Transaction Allocation in Sharded Blockchain Systems](https://mlsanity.com/paper/2212.11584/) (2022)

## Abstract (arXiv)

A major challenge in blockchain sharding protocols is that more than 95% transactions are cross-shard. Not only those cross-shard transactions degrade the system throughput but also double the confirmation time, and exhaust an already scarce network bandwidth. Are cross-shard transactions imminent for sharding schemes? In this paper, we propose a new sharding paradigm, called OptChain, in which cross-shard transactions are minimized, resulting in almost twice faster confirmation time and throughput. By treating transactions as a stream of nodes in an online graph, OptChain utilizes a lightweight and on-the-fly transaction placement method to group both related and soon-related transactions into the same shards. At the same time, OptChain maintains a temporal balance among shards to guarantee the high parallelism. Our comprehensive and large-scale simulation using Oversim P2P library confirms a significant boost in performance with up to 10 folds reduction in cross-shard transactions, more than twice reduction in confirmation time, and 50% increase in throughput. When combined with Omniledger sharding protocol, OptChain delivers a 6000 transactions per second throughput with 10.5s confirmation time.