Data Transmission Service:Migrate data from a self-managed Oracle database to a PolarDB for Oracle cluster

Usage notes

• DTS uses read and write resources of the source and destination databases during full data migration. This may increase the loads of the database servers. If the database performance is unfavorable, the specification is low, or the data volume is large, database services may become unavailable. For example, DTS occupies a large amount of read and write resources in the following cases: a large number of slow SQL queries are performed on the source database, the tables have no primary keys, or a deadlock occurs in the destination database. Before you migrate data, evaluate the impact of data migration on the performance of the source and destination databases. We recommend that you migrate data during off-peak hours. For example, you can migrate data when the CPU utilization of the source and destination databases is less than 30%.

• If a data migration task fails and stops, DTS automatically resumes the task. Before you switch your workloads to the destination database, stop or release the data migration task. Otherwise, the data in the source database overwrites the data in the destination database after the task is resumed.

• If the engine version of your Oracle database is 12c or later, the names of tables to migrate cannot exceed 30 bytes in length.

• If the self-managed Oracle database is deployed in a Real Application Cluster (RAC) architecture and is connected to DTS over an Alibaba Cloud virtual private cloud (VPC), you must connect the Single Client Access Name (SCAN) IP address of the Oracle RAC and the virtual IP address (VIP) of each node to the VPC and configure routes. The settings ensure that your DTS task can run as expected. For more information, see Connect a data center to DTS by using VPN Gateway.

  Important

  When you configure the source Oracle database in the DTS console, you can specify the SCAN IP address of the Oracle RAC as the database endpoint or IP address.

Billing rules

Migration types

Preparations

Log on to the self-managed Oracle database, create an account that you want to use to collect data, and then grant permissions to the account.

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

• Self-managed Oracle database: CREATE USER and GRANT.

• PolarDB for Oracle cluster: Create an account

Enable logging and grant fine-grained permissions to an Oracle database account

1. Enable archive logging and supplemental logging.

   Type	Procedure
   Archive logging	Execute the following statements to enable archive logging: shutdown immediate; startup mount; alter database archivelog; alter database open; archive log list;
   Supplemental logging	Enable supplemental logging at the database or table level based on your business requirements. Note You can enable database-level supplemental logging to ensure the stability of Data Transmission Service (DTS) tasks. You can enable table-level supplemental logging to reduce the disk usage of the source Oracle database. Enable database-level supplemental logging Execute the following statement to enable minimal supplemental logging: alter database add supplemental log data; Execute the following statement to enable primary key and unique key supplemental logging at the database level: alter database add supplemental log data (primary key,unique index) columns; Enable table-level supplemental logging Execute the following statement to enable minimal supplemental logging: alter database add supplemental log data; Enable table-level supplemental logging by using one of the following methods: Enable primary key supplemental logging at the table level alter table table_name add supplemental log data (primary key) columns; Enable table-level supplemental logging for all columns alter table tb_name add supplemental log data (all) columns;
   Force logging	Execute the following statement to enable force logging: alter database force logging;

2. Grant fine-grained permissions to an Oracle database account.

   Oracle versions 9i to 11g

   # Create a database account named rdsdt_dtsacct and grant permissions to the account.
   create user rdsdt_dtsacct IDENTIFIED BY rdsdt_dtsacct;
   grant create session to rdsdt_dtsacct;
   grant connect to rdsdt_dtsacct;
   grant resource to rdsdt_dtsacct;
   grant execute on sys.dbms_logmnr to rdsdt_dtsacct;
   grant select on V_$LOGMNR_LOGS to rdsdt_dtsacct;
   grant select on  all_objects to rdsdt_dtsacct;
   grant select on  all_tab_cols to rdsdt_dtsacct;
   grant select on  dba_registry to rdsdt_dtsacct;
   grant select any table to rdsdt_dtsacct;
   grant select any transaction to rdsdt_dtsacct;
   -- v$log privileges
   grant select on v_$log to rdsdt_dtsacct;
   -- v$logfile privileges
   grant select on v_$logfile to rdsdt_dtsacct;
   -- v$archived_log privileges
   grant select on v_$archived_log to rdsdt_dtsacct;
   -- v$parameter privileges
   grant select on v_$parameter to rdsdt_dtsacct;
   -- v$database privileges
   grant select on v_$database to rdsdt_dtsacct;
   -- v$active_instances privileges
   grant select on v_$active_instances to rdsdt_dtsacct;
   -- v$instance privileges
   grant select on v_$instance to rdsdt_dtsacct;
   -- v$logmnr_contents privileges
   grant select on v_$logmnr_contents to rdsdt_dtsacct;
   -- system tables
   grant select on sys.USER$ to rdsdt_dtsacct;
   grant select on SYS.OBJ$ to rdsdt_dtsacct;
   grant select on SYS.COL$ to rdsdt_dtsacct;
   grant select on SYS.IND$ to rdsdt_dtsacct;
   grant select on SYS.ICOL$ to rdsdt_dtsacct;
   grant select on SYS.CDEF$ to rdsdt_dtsacct;
   grant select on SYS.CCOL$ to rdsdt_dtsacct;
   grant select on SYS.TABPART$ to rdsdt_dtsacct;
   grant select on SYS.TABSUBPART$ to rdsdt_dtsacct;
   grant select on SYS.TABCOMPART$ to rdsdt_dtsacct;
   grant select_catalog_role TO rdsdt_dtsacct;

   Oracle versions 12c to 19c that use the multitenant architecture

   # Switch to the pluggable database (PDB). Create a database account named rdsdt_dtsacct and grant permissions to the account.
   ALTER SESSION SET container = ORCLPDB1;
   create user rdsdt_dtsacct IDENTIFIED BY rdsdt_dtsacct;
   grant create  session to rdsdt_dtsacct;
   grant connect  to rdsdt_dtsacct;
   grant resource to rdsdt_dtsacct;
   grant execute on sys.dbms_logmnr to rdsdt_dtsacct;
   grant select on  all_objects to rdsdt_dtsacct;
   grant select on  all_tab_cols to rdsdt_dtsacct;
   grant select on  dba_registry to rdsdt_dtsacct;
   grant select any table to rdsdt_dtsacct;
   grant select any transaction to rdsdt_dtsacct;
   -- v$log privileges
   grant select on v_$log to rdsdt_dtsacct;
   -- v$logfile privileges
   grant select on v_$logfile to rdsdt_dtsacct;
   -- v$archived_log privileges
   grant select on v_$archived_log to rdsdt_dtsacct;
   -- v$parameter privileges
   grant select on v_$parameter to rdsdt_dtsacct;
   -- v$database privileges
   grant select on v_$database to rdsdt_dtsacct;
   -- v$active_instances privileges
   grant select on v_$active_instances to rdsdt_dtsacct;
   -- v$instance privileges
   grant select on v_$instance to rdsdt_dtsacct;
   -- v$logmnr_contents privileges
   grant select on v_$logmnr_contents to rdsdt_dtsacct;
   grant select on sys.USER$ to rdsdt_dtsacct;
   grant select on SYS.OBJ$ to rdsdt_dtsacct;
   grant select on SYS.COL$ to rdsdt_dtsacct;
   grant select on SYS.IND$ to rdsdt_dtsacct;
   grant select on SYS.ICOL$ to rdsdt_dtsacct;
   grant select on SYS.CDEF$ to rdsdt_dtsacct;
   grant select on SYS.CCOL$ to rdsdt_dtsacct;
   grant select on SYS.TABPART$ to rdsdt_dtsacct;
   grant select on SYS.TABSUBPART$ to rdsdt_dtsacct;
   grant select on SYS.TABCOMPART$ to rdsdt_dtsacct;
   -- V$PDBS privileges
   grant select on V_$PDBS to rdsdt_dtsacct;
   grant select on v$database to rdsdt_dtsacct;
   grant select on dba_objects to rdsdt_dtsacct;
   grant select on DBA_TAB_COMMENTS to rdsdt_dtsacct;
   grant select on dba_tab_cols to rdsdt_dtsacct;
   grant select_catalog_role TO rdsdt_dtsacct;
   
   # Switch to the CDB$ROOT, which is the root container of the container database (CDB). Create a database account and grant permissions to the account.
   ALTER SESSION SET container = CDB$ROOT;
   # Create a database account named rdsdt_dtsacct and grant permissions to the account. You must modify the default parameters of the Oracle database. 
   alter session set "_ORACLE_SCRIPT"=true;
   create user rdsdt_dtsacct IDENTIFIED BY rdsdt_dtsacct;
   grant create session to rdsdt_dtsacct;
   grant connect to rdsdt_dtsacct;
   grant select on v_$logmnr_contents to rdsdt_dtsacct;
   grant LOGMINING TO rdsdt_dtsacct;
   grant EXECUTE_CATALOG_ROLE to rdsdt_dtsacct;
   grant execute on sys.dbms_logmnr to rdsdt_dtsacct;

   Oracle versions 12c to 19c that use a non-multitenant architecture

   # Create a database account named rdsdt_dtsacct and grant permissions to the account.
   create user rdsdt_dtsacct IDENTIFIED BY rdsdt_dtsacct;
   grant create  session to rdsdt_dtsacct;
   grant connect  to rdsdt_dtsacct;
   grant resource to rdsdt_dtsacct;
   grant select on V_$LOGMNR_LOGS to rdsdt_dtsacct;
   grant select on  all_objects to rdsdt_dtsacct;
   grant select on  all_tab_cols to rdsdt_dtsacct;
   grant select on  dba_registry to rdsdt_dtsacct;
   grant select any table to rdsdt_dtsacct;
   grant select any transaction to rdsdt_dtsacct;
   grant select on v$database to rdsdt_dtsacct;
   grant select on dba_objects to rdsdt_dtsacct;
   grant select on DBA_TAB_COMMENTS to rdsdt_dtsacct;
   grant select on dba_tab_cols to rdsdt_dtsacct;
   -- v$log privileges
   grant select on v_$log to rdsdt_dtsacct;
   -- v$logfile privileges
   grant select on v_$logfile to rdsdt_dtsacct;
   -- v$archived_log privileges
   grant select on v_$archived_log to rdsdt_dtsacct;
   -- v$parameter privileges
   grant select on v_$parameter to rdsdt_dtsacct;
   -- v$database privileges
   grant select on v_$database to rdsdt_dtsacct;
   -- v$active_instances privileges
   grant select on v_$active_instances to rdsdt_dtsacct;
   -- v$instance privileges
   grant select on v_$instance to rdsdt_dtsacct;
   -- v$logmnr_contents privileges
   grant select on v_$logmnr_contents to rdsdt_dtsacct;
   grant select on sys.USER$ to rdsdt_dtsacct;
   grant select on SYS.OBJ$ to rdsdt_dtsacct;
   grant select on SYS.COL$ to rdsdt_dtsacct;
   grant select on SYS.IND$ to rdsdt_dtsacct;
   grant select on SYS.ICOL$ to rdsdt_dtsacct;
   grant select on SYS.CDEF$ to rdsdt_dtsacct;
   grant select on SYS.CCOL$ to rdsdt_dtsacct;
   grant select on SYS.TABPART$ to rdsdt_dtsacct;
   grant select on SYS.TABSUBPART$ to rdsdt_dtsacct;
   grant select on SYS.TABCOMPART$ to rdsdt_dtsacct;
   grant LOGMINING TO rdsdt_dtsacct;
   grant EXECUTE_CATALOG_ROLE to rdsdt_dtsacct;
   grant execute on sys.dbms_logmnr to rdsdt_dtsacct;
   grant select_catalog_role TO rdsdt_dtsacct;

Procedure

1. Log on to the DTS console.

   Note

   If you are redirected to the Data Management (DMS) console, you can click the icon in the to go to the previous version of the DTS console.

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

3. At the top of the Migration Tasks page, select the region where the destination cluster resides.

4. In the upper-right corner of the page, click Create Migration Task.

5. Configure the source and destination databases.

   

   Section	Parameter	Description
   N/A	Task Name	The task name that DTS automatically generates. 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	Instance Type	The access method of the source database. In this example, User-Created Database with Public IP Address is selected. Note If you select a different instance type, you must set up the environment that is required for the self-managed database. For more information, see Preparation overview.
   	Instance Region	The region in which the source database resides. If you select User-Created Database with Public IP Address as the instance type, you do not need to specify the Instance Region parameter. Note If an IP address whitelist is configured for the self-managed Oracle database, you must add the CIDR blocks of DTS servers to the IP address whitelist of the database. You can click Get IP Address Segment of DTS next to Instance Region to obtain the CIDR blocks of DTS servers.
   	Database Type	The type of the source database. Select Oracle.
   	Hostname or IP Address	The IP address that is used to connect to the self-managed Oracle database. In this example, the public IP address is entered.
   	Port Number	The service port number of the self-managed Oracle database. Default value: 1521. Note In this example, the service port of the self-managed Oracle database must be accessible over the Internet.
   	Instance Type	If you select Non-RAC Instance, you must specify the SID parameter. If you select RAC or PDB Instance, you must specify the Service Name parameter.
   	Database Account	The account of the self-managed Oracle database. For information about the permissions that are required for the account, see the Preparations section of this topic.
   	Database Password	The password of the database account. Note After you specify the information about the source database, you can click Test Connectivity next to Database Password to check whether the information is valid. If the information is valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Then, modify the information based on the check results.
   Destination Database	Instance Type	The instance type of the destination database. Select PolarDB.
   	Instance Region	The region in which the destination PolarDB for Oracle cluster resides.
   	PolarDB Instance ID	The ID of the destination PolarDB for Oracle cluster.
   	Database Name	The name of the destination database.
   	Database Account	The database account of the destination PolarDB cluster. For information about the permissions that are required for the account, see the Preparations section of this topic.
   	Database Password	The password of the database account. Note After you specify the information about the RDS instance, you can click Test Connectivity next to Database Password to check whether the information is valid. If the information is valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Then, modify the information based on the check results.

6. In the lower-right corner of the page, click Set Whitelist and Next.

   Warning

   If the CIDR blocks of DTS servers are automatically or manually added to the whitelist of the database or instance, or to the ECS security group rules, 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: enhance the security of your username and password, limit the ports that are exposed, authenticate API calls, regularly check the whitelist or ECS security group rules and forbid unauthorized CIDR blocks, or connect the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

7. Select the migration types and the objects to be migrated.

   

   Setting	Description
   Select the 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 Incremental Data Migration is not selected, we recommend that you do not write data to the source database during full data migration. This ensures data consistency between the source and destination databases. If Incremental Data Migration is selected, DTS migrates the ROWID columns in tables without primary keys. This allows you to deduplicate and verify data in tables without primary keys.
   Select the objects to be migrated	Select one or more objects from the Available section and click the icon to add the objects to the Selected section. Note You can select columns, tables, or databases as the objects to be migrated. By default, after an object is migrated to the destination database, the name of the object remains unchanged. You can use the object name mapping feature to rename the objects that are migrated to the destination database. For more information, see Object name mapping. If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be migrated.
   Specify whether to rename objects	You can use the object name mapping feature to rename the objects that are migrated to the destination instance. For more information, see Object name mapping. Note If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be migrated.
   Specify the retry time range for a failed connection to the source or destination database	By default, if DTS fails to connect to the source or destination database, DTS retries within the following 12 hours. You can specify the retry time range based on your business requirements. If DTS is reconnected to the source and destination databases within the specified time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note Within the retry time range in which DTS attempts to reconnect to the source and destination databases, 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 and destination instances are released.

8. In the lower-right corner of the page, click Precheck.

   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, you can click the icon next to each failed item to view details.

     • You can troubleshoot the issues based on the causes and run a precheck again.

     • If you do not need to troubleshoot the issues, you can ignore failed items and run a precheck again.

9. After the task passes the precheck, click Next.

10. In the Confirm Settings dialog box, specify the Channel Specification parameter and select Data Transmission Service (Pay-As-You-Go) Service Terms.

11. Click Buy and Start to start the data migration task.

    • Schema migration and full data migration

      We recommend that you do not manually stop the task during full data migration. Otherwise, the data migrated to the destination database may be incomplete. You can wait until the data migration task automatically stops.

    • Schema migration, full data migration, and incremental data migration

      An incremental data migration task does not automatically stop. You must manually stop the task.

      Important

      We recommend that you select an appropriate time to manually stop the data migration task. For example, you can stop the task during off-peak hours or before you switch your workloads to the destination cluster.

      1. Wait until Incremental Data Migration and The migration task is not delayed appear in the progress bar of the migration task. Then, stop writing data to the source database for a few minutes. The latency of incremental data migration may be displayed in the progress bar.

      2. Wait until the status of incremental data migration changes to The migration task is not delayed again. Then, manually stop the migration task.

12. Switch your workloads to the destination PolarDB cluster.