What are other restrictions on synchronization between RDS and MySQL instances?

It is recommended that the source and target library versions be consistent , Or synchronize from a lower version to a higher version to ensure compatibility . If it is a high version, synchronize to a low version , There may be database compatibility issues . Before performing data synchronization, you need to evaluate the performance of the source library and the target library , At the same time, it is recommended to perform data synchronization in the low peak period . Otherwise, full data initialization will occupy certain read and write resources of the source library and the target library , It may cause the load of the database to increase . Full initialization will be executed concurrently INSERT operation , Cause the table of the target database to fragment , Therefore, after full initialization, the table space of the target instance is larger than that of the source instance . If the synchronization object is a single or multiple tables （ Non integral Library ）, So when data synchronization , Do not use... For synchronization objects of the source library gh-ost or pt-online-schema-change And other similar tools to perform online DDL change , Otherwise, the synchronization will fail . You can use data management DMS（Data Management Service） To perform online DDL change , See structure change of non locking table .

Warning If there is a division DTS External data is written to the target library , Do not use DMS Perform online DDL change , Otherwise, the target database data may be lost .