Migrate data from a MySQL tenant of OceanBase Database to a DB2 LUW 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 DB2 LUW 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 DB2 LUW 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_db2.

      obclient [(none)]> CREATE DATABASE test_ob_to_db2;
      

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

      Switch to the test_ob_to_db2 database.

      obclient [(none)]> USE test_ob_to_db2;
      

      Create a table named tbl1:

      obclient [test_ob_to_db2]> CREATE TABLE tbl1(col1 INT PRIMARY KEY, col2 VARCHAR(20));
      

      Insert the test data:

      obclient [test_ob_to_db2]> 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_db2]> SELECT * FROM tbl1;
      

      Return result:

      +------+-------------+
      | col1 | col2        |
      +------+-------------+
      |    1 | China       |
      |    2 | Taiwan      |
      |    3 | Hong Kong   |
      |    4 | Macao       |
      |    5 | North Korea |
      +------+-------------+
      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 and the read privilege on the gv$sysstat system view.

   Example:

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

      obclient [(none)]> CREATE USER user001 IDENTIFIED BY '******';
      

   2. Grant the required privileges to the user.

      Grant the SELECT privilege on the source database to the user.

      obclient [(none)]> GRANT SELECT ON test_ob_to_db2.* TO 'user001';
      

      Grant the SELECT privilege on the gv$sysstat system view to the user.

      obclient [(none)]> GRANT SELECT ON oceanbase.gv$sysstat TO 'user001';
      

Step 1.2: Configure the destination DB2 LUW database

1. Create a destination schema and table.

   Example:

   Create a schema named test_ob_to_db2_backup in the db2inst2 instance:

   db2 create schema test_ob_to_db2_backup authorization db2inst2
   

   Create a table named tbl1_backup:

   db2 "create table test_ob_to_db2_backup.tbl1_backup(col1 int not null primary key,col2 varchar(20))"
   

2. Grant required privileges to the migration user.

   The migration user must have the sysadm privilege when a DB2 LUW database serves as the source or destination.

   Example:

   db2 update dbm cfg usingSYSADM_GROUP 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 OceanBase data source 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 DB2 LUW data source as the destination data source of the migration project.

   Configure the following parameters.

   Parameter	Description
   Data Source Type	Select DB2_LUW.
   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.
   Host IP Address	The public IP address of the host on which the database is located.
   Port	The port number of the public IP address of the host on which the database is located.
   Database Username	The name of the DB2 LUW database user for data migration or synchronization. We recommend that you create a dedicated database user for the migration or synchronization project.
   Database Password	The password of the database user.
   DB Name	The name of the DB2 LUW database.
   Schema Name (Optional)	The schema name of the DB2 LUW database. This parameter is optional. If you do not specify this parameter, all schemas on which you have the read privilege can be migrated.
   Remarks (Optional)	Additional information about the data source.

   When you configure the data source, you can choose whether to select the following option based on your business needs: 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.

   • If you select this option, OMS creates the drc.heartbeat table in the DB2 LUW 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.
   • If you do not select this option, OMS does not create the drc.heartbeat table.

   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 Source Management 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. Notice The source must not be a MySQL tenant of OceanBase Database V4.0.0.
   Destination	Select the created DB2 LUW data source from the drop-down list. Notice The unique key column in the DB2 LUW database must have the NOT NULL constraint.

   After you configure the parameters, click Next. In the dialog box that appears, 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 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. During the incremental synchronization from a MySQL tenant of OceanBase Database to a DB2 LUW database, the comments are automatically filtered. Incremental Synchronization has the following limitations: 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.
   Full Verification	If you select Full Verification, we recommend that you collect the statistics of the MySQl tenant of OceanBase Database and use the RUNSTATS statement to collect the statistics of the DB2 LUW 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 schemas map to the same destination schema.

   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 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.

   When you migrate data from a MySQL tenant of OceanBase Database to a DB2 LUW database, OMS allows you to import objects by using text files, rename object names, set row filters, view column information, and remove one 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 DB2 LUW database to check whether the data has been migrated.

1. Switch to the test_ob_to_db2_backup schema.

   db2 set current schema test_ob_to_db2_backup
   

2. Query the data in the tbl1_backup table.

   db2 "SELECT * FROM tbl1_backup"
   

   Return result:

   COL1        COL2
   ----------- --------------------
            2 Taiwan
            1 China
            3 Hong Kong
            4 Macao
            5 North Korea
   
   5 record(s) selected.
   

More information

• Migrate data from a MySQL tenant of OceanBase Database to a DB2 LUW database
• What is OMS?
• Create a database user
• Create a DB2 LUW data source
• Create a physical OceanBase data source