Distributed Ledger (DL) is usually considered as a distributed data management architecture. It maintains data records (the ledgers) across distributed nodes based on consensus mechanism and protocols. DL system can trace all the information of data ownership, usage, and trading chains throughout the lifecycle of data production and transactions, and protect the data from illegal use such as tamper-resistant and non-repudiation. It thus can provide endorsement for data rights confirmation, protection, and audit. Blockchain is a typical implementation of DL system. With the emerging of digital economy applications like digital currency and data asset trading, DL technologies gain more and more attentions. However, system performance is one of the key technical bottlenecks for large-scale application of DL systems, and performance optimization has become a research focus of academia and industry. The paper investigated the methods, technologies, and typical solutions of DL performance optimization from following four perspectives: DL system architecture, ledger data structure, consensus mechanism, and message communication.