DDL synchronization between MySQL tenants of OceanBase Database - ApsaraDB for OceanBase

You can synchronize DDL operations when you migrate or synchronize data between MySQL tenants of OceanBase Database.

Important

If you have created an index in the source tenant, it also exists in the destination tenant. Data transmission automatically ignores the index without interrupting the migration process.

Supported DDL operations for synchronization

ALTER TABLE ADD COLUMN
ALTER TABLE MODIFY COLUMN
Important
You can increase the column length but you cannot modify the column type.
ALTER TABLE ALTER COLUMN SET DEFAULT and ALTER TABLE ALTER COLUMN DROP DEFAULT
ALTER TABLE DROP COLUMN
CREATE TABLE
DROP TABLE
TRUNCATE TABLE
CREATE INDEX and ALTER TABLE ADD INDEX
DROP INDEX and ALTER TABLE DROP INDEX
RENAME TABLE and ALTER TABLE RENAME

Limits of DDL statements

If a table to be synchronized involves DDL operations that are not supported, the data migration or synchronization project may be interrupted and unrecoverable data exceptions may occur.
Frequent DDL operations on a table are not supported. After the store finishes a DDL operation, which can be determined based on the timestamp, it proceeds to the next DDL operation. Otherwise, the store may unexpectedly exit and unrecoverable data exceptions may occur.
Make sure that no DDL operations are performed before you create a store and when a store is being started. If log pulling is involved, make sure that no DDL operations are performed during the period from the start time when logs are pulled to the current time. Otherwise, the store may unexpectedly exit and unrecoverable data exceptions may occur.
The table names before and after the RENAME TABLE clause must be both included or both excluded in the list of tables to be synchronized.
If you enable DDL synchronization, the index dropped in the source database by executing the DROP INDEX statement is also dropped in the destination database. This may cause index loss in the destination database.