Migrate data from a PolarDB for PostgreSQL(Compatible with Oracle) cluster to a self-managed Oracle database

Limits

Billing

Migration types

SQL operations that can be incrementally migrated

Permissions required for database accounts

For more information about how to create a database account and grant permissions to the account, see the following topics:

• PolarDB for PostgreSQL (Compatible with Oracle) cluster: Create database accounts
• Self-managed Oracle databases: CREATE USER and GRANT

Procedure

1. Go to the Data Migration Tasks page.
   1. Log on to the Data Management (DMS) console.
   2. In the top navigation bar, click DTS.
   3. In the left-side navigation pane, choose DTS (DTS) > Data Migration.
   Note

   • Operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode and Customize the layout and style of the DMS console.
   • You can also go to the Data Migration Tasks page of the new DTS console.
2. From the drop-down list next to Data Migration Tasks, select the region in which the data migration instance resides.
   Note

   If you use the new DTS console, you must select the region in which the data migration instance resides in the upper-left corner.
3. Click Create Task. In the Create Task wizard, configure the source and destination databases.
   
   Warning

   After you configure the source and destination databases, we recommend that you read the limits that are displayed in the upper part of the page. Otherwise, the task may fail or data inconsistency may occur.

   Section	Parameter	Description

   Section	Parameter	Description
   N/A	Task Name	The name of the task. DTS automatically assigns a name to the task. We recommend that you specify a descriptive name that makes it easy to identify the task. You do not need to specify a unique task name.
   Source Database	Database Type	The type of the source database. Select PolarDB (Compatible with Oracle).
   	Access Method	The access method of the source database. Select Public IP Address.
   	Instance Region	The region in which the source PolarDB for PostgreSQL (Compatible with Oracle) cluster resides.
   	Data Sources	Specifies whether to configure IP addresses and port numbers of multiple nodes in the source cluster. If you select Single Data Source, you must configure the Domain Name or IP Address and Port Number parameters of the primary node in the source PolarDB for PostgreSQL (Compatible with Oracle) cluster. If you select Multiple Data Sources, you must specify the IP addresses and port numbers of multiple nodes, including the primary node, in the source PolarDB for PostgreSQL (Compatible with Oracle) cluster in the IP:Port of Data Sources field. Note If you select Multiple Data Sources and configure the IP:Port of Data Sources parameter, DTS can automatically switch to a new primary node in the PolarDB for PostgreSQL (Compatible with Oracle) cluster during primary/secondary switchover. This is applicable to scenarios such as disaster recovery. In this example, Single Data Source is selected.
   	Domain Name or IP Address	The endpoint of the primary node in the source PolarDB for PostgreSQL (Compatible with Oracle) cluster. Note You can run the ping command on your computer to obtain the IP address that is used to access the source PolarDB for PostgreSQL (Compatible with Oracle) cluster.
   	Port Number	The service port number of the source database. Default value: 1521. Note In this example, the service port of the source database must be accessible over the Internet.
   	IP:Port of Data Sources	The IP addresses and port numbers of multiple nodes, including the primary node, in the source PolarDB for PostgreSQL (Compatible with Oracle) cluster. Separate multiple IP:Port with commas (,).
   	Oracle Type	The architecture of the source database. If you select Non-RAC Instance, you must configure the SID parameter. If you select RAC or PDB Instance, you must configure the Service Name parameter. In this example, Non-RAC Instance is selected.
   	Database Name	The name of the source database in the PolarDB for PostgreSQL (Compatible with Oracle) cluster.
   	Database Account	The database account of the source PolarDB for PostgreSQL (Compatible with Oracle) cluster. For information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account.
   Destination Database	Database Type	The type of the destination database. Select Oracle.
   	Access Method	The access method of the destination database. Select Public IP Address.
   	Instance Region	The region in which the destination Oracle database resides.
   	Hostname or IP Address	The endpoint of the primary node in the destination Oracle database.
   	Port Number	The service port number of the destination database. Default value: 1521.
   	Oracle Type	The architecture of the destination database. If you select Non-RAC Instance, you must configure the SID parameter. If you select RAC or PDB Instance, you must configure the Service Name parameter. In this example, Non-RAC Instance is selected.
   	Database Account	The account of the destination Oracle database. For information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account.

4. If an IP address whitelist is configured for your self-managed database, add the CIDR blocks of DTS servers to the IP address whitelist. Then, click Test Connectivity and Proceed.

   Warning

   If the public CIDR blocks of DTS servers are automatically or manually added to the IP address whitelist of a database instance or to the security group rules of an ECS instance, security risks may arise. Therefore, before you use DTS to migrate data, you must understand and acknowledge the potential risks and take preventive measures, including but not limited to the following measures: enhancing the security of your account and password, limiting the ports that are exposed, authenticating API calls, regularly checking the IP address whitelist or ECS security group rules and forbidding unauthorized CIDR blocks, and connecting the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

5. Configure the objects to be migrated and advanced settings.
   

   Parameter	Description

   Parameter	Description
   Migration Types	To perform only full data migration, select only Full Data Migration. To ensure service continuity during data migration, select Full Data Migration and Incremental Data Migration. Note If you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
   Processing Mode of Conflicting Tables	Precheck and Report Errors: checks whether the destination database contains tables that have the same names as tables in the source database. If the source and destination databases do not contain tables that have identical table names, the precheck is passed. Otherwise, an error is returned during the precheck and the data migration task cannot be started. Note You can use the object name mapping feature to rename the tables that are migrated to the destination database. You can use this feature if the source and destination databases contain tables that have identical table names and the tables in the destination database cannot be deleted or renamed. For more information, see Map object names. Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases. Warning If you select Ignore Errors and Proceed, data inconsistency may occur and your business may be exposed to the following potential risks: If the source and destination databases have the same schemas, DTS does not migrate data records that have the same primary key values as data records in the destination database. If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
   Source Objects	Select one or more objects from the Source Objects section and click the icon to add the objects to the Selected Objects section. Note You can select columns, tables, or schemas as the objects to be migrated. If you select tables or columns as the objects to be migrated, DTS does not migrate other objects, such as views, triggers, or stored procedures, to the destination database.
   Selected Objects	To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object. To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time. Note If you use the object name mapping feature to rename an object, other objects that depend on the object may fail to be migrated. To specify WHERE conditions to filter data, right-click a table in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see Use SQL conditions to filter data. To select the SQL operations performed on a specific database or table, right-click an object in the Selected Objects section. In the dialog box that appears, select the SQL operations that you want to migrate. For more information about the SQL operations that can be migrated, see the SQL operations that can be incrementally migrated section of this topic.

6. Click Next: Advanced Settings to configure advanced settings.
   

   Parameter	Description

   Parameter	Description
   Set Alerts	Specifies whether to configure alerting for the data migration task. If the task fails or the migration latency exceeds the specified threshold, the alert contacts will receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. If you select Yes, you must also specify the alert threshold and alert contacts. For more information, see Configure monitoring and alerting.
   Retry Time for Failed Connections	The retry time range for failed connections. If the source or destination database fails to be connected after the data migration task is started, DTS immediately retries a connection within the time range. Valid values: 10 to 1440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS reconnects to the source and destination databases within the specified time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you set different retry time ranges for multiple data migration tasks that have the same source or destination database, the shortest retry time range that is set takes precedence. When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business requirements. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.
   The wait time before a retry when other issues occur in the source and destination databases.	The retry time range for other issues. For example, if DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set the parameter to a value greater than 10. If the failed operations are successfully performed within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Important The value of the The wait time before a retry when other issues occur in the source and destination databases parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
   Configure ETL	Specifies whether to configure the extract, transform, and load (ETL) feature. For more information, see What is ETL?. Valid values: Yes: configures the ETL feature. You can enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: does not configure the ETL feature.

7. In the lower part of the page, click Next: Save Task Settings and Precheck.

   You can move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters to view the parameters to be specified when you call the relevant API operation to configure the DTS task.

   Note

   • Before you can start the data migration task, DTS performs a precheck. You can start the data migration task only after the task passes the precheck.

   • If the task fails to pass the precheck, click View Details next to each failed item. After you troubleshoot the issues based on the error message, you can run a precheck again.

   • If an alert is triggered for an item during the precheck:

     • If the alert item cannot be ignored, click View Details next to the failed item and troubleshoot the issues. Then, run a precheck again.

     • If the alert item can be ignored, click Confirm Alert Details. In the View Details dialog box, click Ignore. In the message that appears, click OK. Then, click Precheck Again to run a precheck again. If you ignore the alert item, data inconsistency may occur and your business may be exposed to potential risks.

8. Wait until the success rate becomes 100%. Then, click Next: Purchase Instance.

9. On the Purchase Instance page, configure the Instance Class parameter for the data migration instance. The following table describes the parameters.

   Section	Parameter	Description

   Section	Parameter	Description
   New Instance Class	Resource Group	The resource group to which the data migration instance belongs. Default value: default resource group. For more information, see What is Resource Management?
   	Instance Class	DTS provides instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Specifications of data migration instances.

10. Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.

11. Click Buy and Start to start the data migration task. You can view the progress of the task in the task list.