Dm Embedded Database Data Replication System Design And Implementation

With the continuous development of embedded technology, embedded software, data processing capacity is increasing. People had to use the original complex in the enterprise database processing technology into the embedded systems are go, database technology in embedded systems will come into being.Compared with traditional databases, embedded databases often have mobility. In order to meet anytime and anywhere access to data, data processing requirements for embedded computing environment and the characteristics of mobile computing environment, people made a variety of data replication based or cache an effective manner. Mobile devices running on embedded applications can be accessed directly through the embedded database engine, a local copy of local data, which data is copied from a central server synchronization, and then perform various operations on the data locally and then synchronize data To the central servers and other computing nodes.DM embedded database is developed as a sophisticated embedded database software by Wuhan DM Database Co.,Ltd. DM embedded database replication subsystem is an important module that supports synchronous replication and asynchronous replication among DM embedded database as well as between DM and DM embedded databaseData replication in a distributed environment, the difficulty is to guarantee the data consistency between multiple nodes. Replication implementation is a strong consistency, and asynchronous replication is a weak consistency. For replication, two-phase commit protocol (2PC) provides us with a good solution. DM embedded database replication using 2PC to implement to ensure that the master server and the transaction from the server between the strong consistency.Asynchronous replication is relatively simple, DM embedded database to provide the relevant interface, the application calls in order to achieve more consistent data between nodes. In data capture, there two ways which based on the triggers and based on the log. Simple trigger-based approach, but occupy more system resources. Although the log-based approach to achieve more complex, but more flexible. Taking into account the cost of resources, flexibility, and the combination of database and of DM, of DM embedded database approach based on log data replication.