Migrate data from a PolarDB for PostgreSQL cluster to an ApsaraDB RDS for PostgreSQL instance

Procedure

1. Use one of the following methods to go to the Data Migration page and select the region in which the data migration instance resides.

   DTS console

   DMS console

   1. Log on to the DTS console.

   2. In the left-side navigation pane, click Data Migration.

   3. In the upper-left corner of the page, select the region in which the data migration instance resides.

   Note

   The actual operation 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.

   1. Log on to the DMS console.

   2. In the top navigation bar, move the pointer over Data Development > DTS (DTS) > Data Migration .

   3. From the drop-down list to the right of Data Migration Tasks, select the region in which the data synchronization instance resides.

2. Click Create Task to go to the task configuration page.

3. Optional. Click New Configuration Page in the upper-right corner of the page.

   Note

   1. Skip this step if the Back to Previous Version button is displayed in the upper-right corner of the page.

   2. Specific parameters in the new and previous versions of the configuration page may be different. We recommend that you use the new version of the configuration page.

4. Configure the source and destination databases. The following table describes the parameters.

   Section	Parameter	Description

   Section	Parameter	Description
   N/A	Task Name	The name of the DTS task. DTS automatically generates a task name. 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 for PostgreSQL.
   	Access Method	The access method of the source database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the source PolarDB for PostgreSQL cluster resides.
   	Replicate Data Across Alibaba Cloud Accounts	Specifies whether to migrate data across Alibaba Cloud accounts. In this example, No is selected.
   	Instance ID	The ID of the source PolarDB for PostgreSQL cluster.
   	Database Name	The name of the source database in the PolarDB for PostgreSQL cluster.
   	Database Account	The database account of the PolarDB for PostgreSQL cluster.
   	Database Password	The password that is used to access the database.
   Destination Database	Database Type	The type of the destination database. Select PostgreSQL.
   	Access Method	The access method of the destination database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the destination ApsaraDB RDS for PostgreSQL instance resides.
   	Instance ID	The ID of the destination ApsaraDB RDS for PostgreSQL instance.
   	Database Name	The name of the destination database in the ApsaraDB RDS for PostgreSQL instance.
   	Database Account	The database account of the destination ApsaraDB RDS for PostgreSQL instance.
   	Database Password	The password that is used to access the database.
   	Encryption	Specifies whether to encrypt the connection to the source database. You can configure this parameter based on your business requirements. In this example, Non-encrypted is selected. If you want to establish an SSL-encrypted connection to the source database, perform the following steps: Select SSL-encrypted, upload CA Certificate, Client Certificate, and Private Key of Client Certificate as needed, and then specify Private Key Password of Client Certificate. Note If you set Encryption to SSL-encrypted for a self-managed PostgreSQL database, you must upload CA Certificate. If you want to use the client certificate, you must upload Client Certificate and Private Key of Client Certificate and specify Private Key Password of Client Certificate. For information about how to configure SSL encryption for an ApsaraDB RDS for PostgreSQL instance, see SSL encryption.

5. Click Test Connectivity and Proceed in the lower part of the page.

   Note

   • Make sure that the CIDR blocks of DTS servers can be automatically or manually added to the security settings of the source and destination databases to allow access from DTS servers. For more information, see Add the CIDR blocks of DTS servers.

   • If the source or destination database is a self-managed database and its Access Method is not set to Alibaba Cloud Instance, click Test Connectivity in the CIDR Blocks of DTS Servers dialog box.

6. Configure the objects to be migrated.

   1. On the Configure Objects page, configure the objects that you want to migrate.

      Parameter	Description

      Parameter	Description
      Migration Types	To perform only full data migration, select Schema Migration and Full Data Migration. To ensure service continuity during data migration, select Schema Migration, 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 use 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 If the source and destination databases contain tables with identical names and the tables in the destination database cannot be deleted or renamed, you can use the object name mapping feature to rename the tables that are migrated to the destination database. 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 schema, and a data record has the same primary key as an existing data record in the destination database, the following scenarios may occur: During full data migration, DTS does not migrate the data record to the destination database. The existing data record in the destination database is retained. During incremental data migration, DTS migrates the data record to the destination database. The existing data record in the destination database is overwritten. If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
      Capitalization of Object Names in Destination Instance	The capitalization of database names, table names, and column names in the destination instance. By default, DTS default policy is selected. You can select other options to make sure that the capitalization of object names is consistent with that of the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.
      Source Objects	Select one or more objects from the Source Objects section. Click the icon to add the objects to the Selected Objects section.
      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 the Map the name of a single object section of the Map object names topic. To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see the Map multiple object names at a time section of the Map object names topic. 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.

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

      Parameter	Description

      Parameter	Description
      Dedicated Cluster for Task Scheduling	By default, DTS schedules the data migration task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data migration tasks, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.
      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 retry 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 is reconnected to the source and destination databases within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you specify different retry time ranges for multiple data migration tasks that share the same source or destination database, the value that is specified later 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 the earliest opportunity after the source database and destination instance are released.
      Retry Time for Other Issues	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 Retry Time for Other Issues parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
      Enable Throttling for Full Data Migration	Specifies whether to enable throttling for full data migration. During full data migration, DTS uses the read and write resources of the source and destination databases. This may increase the loads of the database servers. You can enable throttling for full data migration based on your business requirements. To configure throttling, you must configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Full Data Migration for the Migration Types parameter.
      Enable Throttling for Incremental Data Migration	Specifies whether to enable throttling for incremental data migration. To configure throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This reduces the loads of the destination database server. Note You can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.
      Environment Tag	The environment tag that is used to identify the DTS instance. You can select an environment tag based on your business requirements. In this example, you do not need to configure this parameter.
      Configure ETL	Specifies whether to enable 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.
      Monitoring and Alerting	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 receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see the Configure monitoring and alerting when you create a DTS task section of the Configure monitoring and alerting topic.

   3. Click Next Step: Data Verification to configure the data verification task.

      For more information about how to use the data verification feature, see Configure a data verification task.

7. Save the task settings and run a precheck.

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

   2. If you do not need to view or have viewed the parameters, click Next: Save Task Settings and Precheck in the lower part of the page.

   Note

   1. 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.

   2. If the task fails to pass the precheck, click View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, run a precheck again.

   3. If an alert is triggered for an item during the precheck:

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

      2. 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. Purchase an instance.

   1. Wait until the Success Rate becomes 100%. Then, click Next: Purchase Instance.

   2. 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 Instance classes of data migration instances.

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

   4. Click Buy and Start. In the message that appears, click OK.

      You can view the progress of the task on the Data Migration page.