Abstract: NoSQL databases have very good read/write performance and scalability in Big data analysis and processing, but they cannot support complete SQL queries and transactions across tables or rows, which limits the application of financial business based on the traditional relation databases. OceanBase, a distributed database, combines the advantages of relational databases and nonrelational databases, supporting relational queries and transactions across tables or rows. However, at present OceanBase only supports simple and nonnested queries which cannot meet the needs of financial business. After studying the OceanBase architecture and query strategy, a new strategy based on BloomFilter and HashMap is proposed in this paper. Experiments show that the strategy can improve the existing query strategy and enhance query performance.

Key words: OceanBase, NoSQL, nested queries, big data