Smarter Contract Upgrades with Orthogonal Persistence

Abstract

Altering the smart contract deployed on a blockchain is typically a cumbersome task, necessitating a proxy design, secondary data storage, or the use of special APIs. This can be substantially simplified if the programming language features orthogonal persistence, automatically retaining the native program state across program version upgrades. For this purpose, a customized compiler and runtime system needs to arrange the data in a self-descriptive portable format, such that new program versions can pick up the previous program state, check their compatibility, and support implicit or explicit data evolutions. We have implemented such advanced persistence support for the Motoko programming language on the Internet Computer blockchain. This not only enables simple and safe persistence, but also significantly reduces the cost of upgrades and data accesses.