Migration type | Description |
Schema migration | The definitions of data objects, such as tables, indexes, constraints, comments, and views, are migrated from the source database to the target database. Temporary tables are automatically filtered out. If the source database is not an OceanBase database, the data migration service performs format conversion and encapsulation based on the syntax definition and standard of the type of the target OceanBase Database tenant, and then replicates the data to the target database. |
Full migration | The existing data is migrated from tables in the source database to the corresponding tables in the target database. On the Full Migration page, you can filter objects by source and target databases, or select View Objects with Errors to filter out objects that hinder the overall migration progress. You can view Tables, Table Indexes, and Full Load Performance. The status of a full migration task changes to Completed only after both the table objects and table indexes are migrated. |
Incremental synchronization | After incremental synchronization starts, OMS Community Edition synchronizes the data that has been changed (added, modified, or deleted) in the source database to the corresponding tables in the target database. When services continuously write data to the source database, the data transmission service starts the incremental data pull module to pull incremental data from the source instance, parses and encapsulates the incremental data, and then stores the data. After that, the data transmission service starts the full migration. After the full migration task is completed, the data transmission service starts the incremental data replay module to pull incremental data from the incremental data pull module. The incremental data is synchronized to the target database after being filtered, mapped, and converted. |
Full verification | After the full migration and incremental data migration are completed, the data transmission service automatically initiates a full verification task to verify the data tables in the source and target data sources. You can also initiate custom data verification tasks in the incremental data synchronization process. On the Full Verification page, you can view the overall status, start time, end time, total consumed time, estimated total number of rows, number of migrated rows, real-time traffic, and RPS of the full verification task. |
Forward switchover | Forward switchover is an abstract and standard process of traditional system cutover and does not involve the switchover of application connections. This process includes a series of tasks that are performed for application switchover in a data migration task. You must make sure that the entire forward switchover process is completed before the application connections are switched over to the target database. Forward switchover is required for data migration. The data transmission service can ensure the completion of forward data migration in this process, and you can start the reverse incremental synchronization component based on your business needs. The forward switchover process involves the following operations: You must make sure that data migration is completed and wait until forward synchronization is completed. The data transmission service automatically supplements the check constraints and FOREIGN KEY constraints that are ignored in schema migration when you migrate data to an Oracle database or an Oracle tenant of OceanBase Database. The data transmission service automatically deletes the hidden columns and unique indexes on which the migration depends. This operation is performed only for data migration between an Oracle database and an OceanBase database or between OceanBase databases. For more information, see Hidden column mechanisms. You must migrate triggers, functions, and stored procedures in the source database that are not supported by the data transmission service to the target database. You must disable triggers and FOREIGN KEY constraints in the source database. This operation is required only when the data migration task involves reverse incremental synchronization.
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Reverse incremental synchronization | In business cutover scenarios, after the migration is completed, you can start an incremental synchronization task in a reverse direction before the business database switchover. This data synchronization task synchronizes incremental data from the target database to the source database in real time. |
Elastic Compute Service (ECS)
Container Compute Service (ACS)
