DDL synchronization between MySQL-compatible tenants of OceanBase Database

This topic introduces the DDL statements supported for synchronization between MySQL-compatible tenants of OceanBase Database.

Supported DDL statements

• 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

  Notice

  CREATE TABLE AS SELECT is not supported.

• 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 the tables to be synchronized involve unsupported DDL statements, the migration task may be interrupted, causing data inconsistency, and the data may not be able to be recovered.

• It is not advisable to perform frequent DDL operations on a single table. After the store completes the current DDL operation (based on the timestamp), the next DDL operation should be performed. Otherwise, the store may experience abnormal termination 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 from the time point when the logs are pulled to the current time point. Otherwise, the store may experience abnormal termination or cause unrecoverable data exceptions.

• The table names before and after the RENAME TABLE operation must be present in the list of tables to be synchronized.