面向区块链的高效物化视图维护和可信查询

The blockchain system is favored by many fields, such as finance and logistics due to several unique properties, including decentralized architecture, data immutability and data traceability. Transactions belonging to the same type are commonly distributed in massive blocks because all transactions are stored in chronological order of transaction committing, which lowers the efficiency to process tracing queries where a huge number of historical blocks are involved. Although indexing and materialized view are two typical ways to boost query performance, indexing cannot lower the I/O cost if the data to be processed are widely distributed in the system. Fortunately, materialized view suits for this scenario well. Furthermore, as traditional materialized view technologies for RDBMS cannot be directly adopted to blockchain due to significant difference between them, a set of materialized view mechanisms is firstly proposed for blockchain with the following properties: (1) To lower the impact to the system, the view maintenance operation is executed in parallel with consensus process; (2) Trie-Tree is used to speed up multi-materialized view maintenance process in blocks; (3) the query results is guaranteed credible by ensuring the materialized results not falsified with Merkle verification. After integrating the proposed materialized view maintenance mechanism into a blockchain system, experimental results show that the proposed method is convenient and efficient.