Migrate data from a MySQL tenant of OceanBase Database to a MySQL database by using OMS

OceanBase Migration Service (OMS) is a service that supports data interaction between OceanBase Database and homogeneous or heterogeneous data sources. It supports online data migration and real-time synchronization of incremental data. OMS provides a visualized and centralized management platform. You can migrate data in real time with simple configurations.

This topic describes how to migrate all data from a MySQL tenant of OceanBase Database to a MySQL database by using OMS V4.0.2.

Prerequisites

• You have deployed OMS V4.0.2. For more information about how to deploy OMS, see Deployment types.
• You have a MySQL tenant of OceanBase Database to serve as the source data source for data migration. For more information about user tenants, see User tenants.
• You have a MySQL database to serve as the destination data source for data migration.

Procedure

1. Configure the source and destination data sources.
2. Create data sources.
3. Create a full data migration project and start the project.
4. View the data migration status.

Step 1: Configure the source and destination data sources

The following table describes information about the test environment.

Step 1.1: Configure the source MySQL tenant of OceanBase Database

1. Create test data for the source data source.

   Example:

   1. Create a source database named test_ob_to_mysql.

      obclient [(none)]> CREATE DATABASE test_ob_to_mysql;
      

   2. Create a source table named tbl1 and insert data into it.

      Switch to the test_ob_to_mysql database:

      obclient [(none)]> USE test_ob_to_mysql;
      

      Create a table named tbl1:

      obclient [test_ob_to_mysql]> CREATE TABLE tbl1(col1 INT PRIMARY KEY, col2 VARCHAR(20),col3 DATETIME DEFAULT CURRENT_TIMESTAMP);
      

      Insert the test data:

      obclient [test_ob_to_mysql]> INSERT INTO tbl1(col1,col2) VALUES(1,'China'),(2,'Taiwan'),(3,'Hong Kong'),(4,'Macao'),(5,'North Korea');
      

      View the test data:

      obclient [test_ob_to_mysql]> SELECT * FROM tbl1;
      

      Return result:

      +------+-------------+---------------------+
      | col1 | col2        | col3                |
      +------+-------------+---------------------+
      |    1 | China       | 2023-04-25 14:37:58 |
      |    2 | Taiwan      | 2023-04-25 14:37:58 |
      |    3 | Hong Kong   | 2023-04-25 14:37:58 |
      |    4 | Macao       | 2023-04-25 14:37:58 |
      |    5 | North Korea | 2023-04-25 14:37:58 |
      +------+-------------+---------------------+
      5 rows in set
      

2. Create a migration user for the source database and grant the required privileges to the user.

   The migration user must have the SELECT privilege on the source database.

   Example:

   1. Create a migration user named user001 for the source database.

      obclient [test_ob_to_mysql]> CREATE USER user001 IDENTIFIED BY '******';
      

   2. Grant the required privileges to the user.

      obclient [test_ob_to_mysql]> GRANT SELECT ON test_ob_to_mysql.* TO 'user001';
      

Step 1.2: Configure the destination MySQL database

1. Create a database for the destination MySQL Database.

   Example:

   1. Create a destination database named test_ob_to_mysql_backup.

      MySQL [(none)]> CREATE DATABASE test_ob_to_mysql_backup;
      

   2. Create a destination table named tbl1_backup.

      Switch to the test_ob_to_mysql_backup database:

      MySQL [(none)]> USE test_ob_to_mysql_backup;
      

      Create a table named tbl1_backup:

      MySQL [test_ob_to_mysql_backup]> CREATE TABLE tbl1_backup(col1 INT PRIMARY KEY, col2 VARCHAR(20),col3 DATETIME);
      

2. Create a migration user for the destination data source and grant the required privileges to the user.

   The migration user must have the CREATE, CREATE VIEW, INSERT, UPDATE, and DELETE privileges on the destination database.

   Example:

   1. Create a migration user named user001_backup for the destination data source.

      MySQL [test_ob_to_mysql_backup]> CREATE USER 'user001_backup'@'%' IDENTIFIED BY '******';
      

   2. Grant the required privileges to the user.

      MySQL [test_ob_to_mysql_backup]> GRANT CREATE,CREATE VIEW,INSERT,UPDATE,DELETE ON test_ob_to_mysql_backup.* TO 'user001_backup';
      

Step 2: Create data sources

1. Log on to the OMS console.

2. On the Data Source Management page, click New Data Source.

3. Create a physical data source for the MySQL tenant of OceanBase Database as the source data source of the migration project.

   Configure the following parameters.

   Parameter	Description
   Data Source Type	Select OceanBase and Physical Data Source.
   Data Source Identifier	We recommend that you set it to a combination of digits and letters. It must not contain any spaces and cannot exceed 32 characters in length.
   Region	Select the region where the data source resides from the drop-down list. The region is the value that you set for the cm_region parameter when you deploy OMS. Notice This parameter is displayed only when multiple regions are available. Make sure that the mappings between the data source and the region are consistent. Otherwise, the migration and synchronization performance can be poor.
   Tenant Type	Select MySQL. The type of the OceanBase Database tenant. Valid values: Oracle and MySQL.
   OCP Cluster (Optional)	The OceanBase Cloud Platform (OCP) cluster associated with the data source. Select an OCP cluster from the drop-down list. Note Check whether the data source is managed in the selected OCP cluster. This parameter ensures that OMS obtains the incremental data of the OceanBase database. If you do not set this parameter, you cannot select Incremental Migration, Incremental Synchronization, or Reverse Incremental Migration. If the OCP cluster is not available in the list, click Add OCP Cluster and configure the parameters on the Add Associated OCP Cluster page.
   Connection Mode	Valid values: Manual Input and Command-line Connection String. Manual Input: Enter the public IP address and port number of the OceanBase database. Command-line Connection String: Enter a command-line connection string. This option is optional.
   Host IP Address	The IP address of the host where the database is located.
   Port	The port number of the host where the database is located.
   Tenant Name	The name of the OceanBase Database tenant.
   Cluster Name	The name of the cluster to which the OceanBase Database tenant belongs.
   Database Username	The username of the OceanBase database user for data migration or synchronization. We recommend that you create a dedicated database user for data migration or synchronization.
   Database Password	The password of the database user.
   Database Name (Optional)	The name of the database.
   Remarks (Optional)	Additional information about the data source.

   After you configure the parameters, click Test Connection to verify the network connection between OMS and the data source, as well as the validity of the username and password. After the connection test succeeds, click OK.

4. Create a MySQL data source as the destination data source of the migration project.

   Configure the following parameters.

   Parameter	Description
   Data Source Type	Select MySQL.
   Data Source Identifier	We recommend that you set it to a combination of digits and letters. It must not contain any spaces and cannot exceed 32 characters in length.
   Region	Select the region where the data source resides from the drop-down list. The region is the value that you set for the cm_region parameter when you deploy OMS. Notice This parameter is displayed only when multiple regions are available. Make sure that the mappings between the data source and the region are consistent. Otherwise, the migration and synchronization performance can be poor.
   Database Attributes	Select Primary Database. Valid values: Primary Database, Primary Database + Standby Database, and Standby Database.
   Host IP Address	The IP address of the host where the database is located. You must specify the IP address of the physical server that hosts the Relational Database Service (RDS). Do not enter the IP address of any middleware.
   Port	The port number of the host where the database is located.
   Database Username	The name of the MySQL database user for data migration or synchronization.
   Database Password	The password of the database user.
   Database Name (Optional)	The name of the MySQL database.
   Allow OMS to automatically write heartbeat data into this instance during incremental synchronization. This resolves the problem of high latency when no business data is written in the source database.	Optional. If you select this option, OMS creates the drc.heartbeat table in the MySQL database and updates the table to store the synchronization timestamps. This prevents OMS from displaying lengthy latency information when the source database is not processing business traffic. Notice The MySQL database user must have the privileges to create and write tables. If you do not select this option, OMS does not create the drc.heartbeat table.
   Remarks (Optional)	Additional information about the data source.

   After you configure the parameters, click Test Connection to verify the network connection between OMS and the data source, as well as the validity of the username and password. After the connection test succeeds, click OK.

Step 3: Create a full data migration project and start the project

1. On the Data Migration page, click Create Migration Project in the upper-right corner.

2. On the Select Source and Destination page, configure the following parameters.

   Parameter	Description
   Migration Project Name	We recommend that you set it to a combination of digits and letters. It must not contain any spaces and cannot exceed 64 characters in length.
   Tag (Optional)	Click the field and select a target tag from the drop-down list. You can also click Manage Tags to create, modify, and delete tags.
   Source	Select the data source created for a MySQL tenant of OceanBase Database from the drop-down list.
   Destination	Select the created MySQL data source from the drop-down list.

   After you configure the parameters, click Next.

   Note

   Note that this project supports only tables with a primary key or a non-null unique index. Other tables and views are automatically filtered out. After you read the message in the dialog box, click OK.

3. On the Select Migration Type page, configure the following parameters.

   Options for Migration Type are Schema Migration, Full Migration, Incremental Synchronization, Full Verification and Reverse Incremental Migration.

   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 destination database. Temporary tables are automatically filtered out.
   Full Migration	If you select Full Migration, we recommend that you collect the statistics of the source MySQL tenant of OceanBase Database before the data migration.
   Incremental Synchronization	Options for Incremental Synchronization are DML Synchronization and DDL Synchronization. You can select the operations as needed. Incremental Synchronization has the following limitations: OceanBase Database V1.x does not support incremental synchronization. A standby MySQL database does not support incremental synchronization. If you select DDL Synchronization, when you perform a DDL operation that cannot be synchronized by OMS in the source database, data migration may fail. If the DDL operation creates a new column, we recommend that you set the attribute of the column to Null. Otherwise, data migration may be interrupted. If you insert columns without data during incremental synchronization, the previous data will be padded based on the current time, causing time inconsistency.
   Full Verification	If you select Full Verification, we recommend that you collect the statistics of the MySQL tenant of OceanBase Database before full verification and execute the ANALYZE statement to collect statistics of the MySQL database before full verification. If you selected Incremental Synchronization but did not select all DML statements in DML Synchronization, OMS does not support full data verification in this case.
   Reverse Incremental Migration	You cannot select Reverse Incremental Migration in the following cases: Multi-table aggregation and synchronization is enabled. Multiple source databases map to the same destination database.

   Select Full Migration, specify the parameters, and then click Next.

4. On the Select Migration Objects page, select the migration objects and migration scope.

   You can select Specify Objects or Match Rules to specify the migration objects. If you selected DDL Synchronization, only the Match Rules option is available.

   If you select Specify Objects, select the objects to be migrated on the left and click > to add them to the list on the right. You can select tables and views of one or more databases as the migration objects.

   Notice

   • The names of tables to be migrated, as well as the names of columns in the tables, must not contain Chinese characters.
   • If the database or table name contains a double dollar sign ($$), you cannot create the migration project.

   OMS also allows you to import objects from text, rename object names, set row filters, view column information, and remove a single object or all objects to be migrated.

   Operation	Steps
   Import Objects	In the list on the right of the Specify Migration Scope section, click Import Objects in the upper-right corner. In the dialog box that appears, click OK. Notice This operation overwrites previous selections. Proceed with caution. In the Import Objects dialog box, import the objects to be migrated. You can import CSV files to rename databases/tables and set row filtering conditions. Click Validate. After the validation succeeds, click OK.
   Rename	OMS allows you to rename migration objects.
   Settings	OMS allows you to use the WHERE clause to filter data by row. You can also view column information about the migration objects in the View Columns section.
   Remove/Remove All	During data mapping, OMS allows you to remove one or more selected objects to be migrated to the destination. Remove a single migration object: In the list on the right of the Specify Migration Scope section, move the pointer over the object that you want to remove, and then click Remove. Remove all migration objects: In the list on the right of the Specify Migration Scope section, click Remove All in the upper-right corner. In the dialog box that appears, click OK.

   After you configure the parameters, click Next.

5. On the Migration Options page, configure the parameters for full migration.

   Parameter	Description
   Concurrency for Full Migration	The value can be Smooth, Normal, or Fast. The number of resources to be consumed by a full data migration task varies based on the migration performance. You can define the concurrency for full migration by modifying the configurations of the Full-Import component. Note You can set this option only when Full Migration is selected on the Select Migration Type page.
   Whether to Allow Destination Table to Be Not Empty During Full Migration	If destination tables are allowed to be not empty during full migration, full verification is performed in IN mode. Note You can set this option only when Full Migration is selected on the Select Migration Type page.

   After you configure the parameters, click Precheck.

6. On the Precheck page, handle Failed check items.

   During the precheck, OMS checks the read and write privileges of the database users and the network connections of the databases. The data migration project can be started only after it passes all check items. If an error is returned during the precheck:

   • You can identify and troubleshoot the problem and then perform the precheck again.
   • You can also click Skip in the Actions column of a failed precheck item. In the dialog box that appears, you can view the prompt for the consequences of the operation and click OK.

   After the precheck succeeds, click Start Project.

   Note

   If you do not need to start the project now, click Save to go to the details page of the data migration project. You can start the project later as needed.

7. On the Migration Details page, click Start Forward Switchover.

8. Wait for the task to complete.

Step 4: View the data migration status

Log on to the MySQL database to check whether the data has been migrated.

1. Log on to the MySQL database.

   $mysql -hxxx.xxx.xxx.xxx -P3306 -uxxxx -p****** -Dtest_ob_to_mysql_backup
   

2. View the data in the tbl1_backup table.

   MySQL [test_ob_to_mysql_backup]> SELECT * FROM tbl1_backup;
   

   Return result:

   +------+-------------+---------------------+
   | col1 | col2        | col3                |
   +------+-------------+---------------------+
   |    1 | China       | 2023-04-25 14:37:58 |
   |    2 | Taiwan      | 2023-04-25 14:37:58 |
   |    3 | Hong Kong   | 2023-04-25 14:37:58 |
   |    4 | Macao       | 2023-04-25 14:37:58 |
   |    5 | North Korea | 2023-04-25 14:37:58 |
   +------+-------------+---------------------+
   5 rows in set
   

More information

• Migrate data from a MySQL tenant of OceanBase Database to a MySQL database
• What is OMS?
• Create a database user
• User privileges
• Create a MySQL data source
• Create a physical OceanBase data source