Dual-database servers implement distributed data operations and hardware failover

Functions provided:
1. When a large amount of data is added for modification and summary query, the two types of data operations are performed independently on the corresponding server,
2. When a server crashes, the program uses the connection pool of the other server for operations. When the crashed server resumes running, the program re-uses the server connection pool.
3. When the disk of one server is damaged, data can be restored from the other server after the restoration.
4. When data is deleted by mistake or damaged by hackers, data can be recovered from the backup data of the Publishing Server.Erection instructions:
1. The two servers establish active publishing and subscription relationships.
2. Create a backup plan on the Publishing Server. All backup methods are used at every day.
3. Create two connection pools in the data access process, which correspond to the [Publishing Server] and [subscription server] respectively.
4. when the server receives a data operation request, it determines the request type. If it is a [change operation], it uses the data connection pool of the [Publishing Server, if it is a [query operation], use the data connection pool of the [subscription server.