What Risky Operations on RDS for MySQL Will Affect DDM?

Operations on the RDS for MySQL console

Deleting an RDS for MySQL instance

After an RDS for MySQL instance is deleted, all schemas and logical tables of the DDM instance associated with the RDS instance become unavailable.

Performing the primary/standby switchover of an RDS for MySQL instance

RDS for MySQL may be intermittently interrupted during the primary/standby switchover. In addition, a small amount of data may be lost in case of long delay in primary/standby synchronization.

• Creating schemas or logical tables is not allowed on DDM during the primary/standby switchover of the RDS for MySQL instance.
• After a primary/standby switchover of an RDS for MySQL instance, the RDS instance ID remains unchanged in DDM.

Restarting an RDS for MySQL instance

The restart of an RDS for MySQL instance makes itself unavailable and will also affect the associated DDM instance.

Resetting a password

After the RDS for MySQL instance password is reset, enter the new password on DDM when you create a schema.

Modifying a parameter template

The following parameters are set to fixed values. If their values are modified, DDM will not function properly.

• lower_case_table_names: Set this parameter to 1, indicating that data table names and sequence names are case-insensitive.
• local_infile: Set this parameter to ON in scale-out scenarios.

Modifying a security group

Your DDM instance cannot connect to associated RDS for MySQL instances.

Modifying a VPC

The DDM instance and RDS for MySQL instance cannot communicate with each other if they are in different VPCs.

Restoring data

Restoring data may damage data integrity.

Operations through an RDS for MySQL client

Deleting a physical database created on DDM

After a physical database is deleted, the original data will be lost and new data cannot be written into the database.

Deleting an account created on DDM

After an account is deleted, logical tables cannot be created on DDM.

Deleting a physical table created on DDM

After a physical table is deleted, data stored on DDM will be lost. The corresponding logical table becomes unavailable on DDM.

Modifying the name of a physical table created on DDM

DDM cannot obtain data of the corresponding logical table, and the logical table becomes unavailable on DDM.

Changing a record

Changing a record in a broadcast table will affect the data consistency of shards.

Modifying a whitelist

A DDM instance cannot access the RDS for MySQL instance if it is not in the RDS instance whitelist.