DDL synchronization between MySQL tenants of OceanBase Database

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

Supported DDL operations

• ALTER TABLE ADD COLUMN

• ALTER TABLE MODIFY COLUMN

  Notice

  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

Limitations

• If a table to be synchronized involves DDL operations that are not supported, the migration project may fail and unrecoverable data exceptions may be caused.

• 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 exit unexpectedly or cause unrecoverable data exceptions.

• 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 exit unexpectedly or cause unrecoverable data exceptions.

• The table names before and after the RENAME TABLE statement must be both included or both not included 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.