Abstract: OceanBase is a distributed scalable relational database.Its storage architecture is designed by separating baseline static data and increment dynamic data, whose memory transaction engine, namely Memtable, provide dynamic data storage, write, and query, clients wrote data to the inmemory data structure. Memtable and some transaction management structures together form the inmemory database engine, which can achieve the transaction ACID properties. Bybased multiversion concurrency control techniques to prevent reading and writing from blocking each other to achieve readonly transactions to meet thesnapshot isolationlevel; Provide multiwrite concurrency control by using classic rowlock technology to meet theread committedtransaction isolation level.