Data Transmission Service:Migrate data from a self-managed Oracle database to an ApsaraDB RDS for MySQL instance

Prerequisites

• The version of the self-managed Oracle database is 9i, 10g, 11g, 12c, 18c, or 19c.

• Supplemental logging, including SUPPLEMENTAL_LOG_DATA_PK and SUPPLEMENTAL_LOG_DATA_UI, is enabled for the self-managed Oracle database. For more information, see Supplemental Logging.

• The self-managed Oracle database is running in ARCHIVELOG mode. Archived log files are accessible and a suitable retention period is set for archived log files. For more information, see Managing Archived Redo Log Files.

• The size of available storage in the RDS instance is greater than the size of data that you want to migrate from the self-managed Oracle database.

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%.

• The tables to be migrated in the source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.

• 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.

• Table names in the ApsaraDB RDS for MySQL instance are not case-sensitive. If a table name in the self-managed Oracle database contains uppercase letters, ApsaraDB RDS for MySQL converts the uppercase letters to lowercase letters and then creates the table.

  If the self-managed Oracle database contains identical table names that differ only in capitalization, the table names are identified as duplicates. As a result, the "The object already exists" message may be displayed during schema migration. To prevent table name conflicts, you can rename the migrated objects by using the object name mapping feature of DTS. For more information, see Object name mapping.

• DTS automatically creates a database in the ApsaraDB RDS for MySQL instance. However, if the name of the source database does not conform to the naming conventions of ApsaraDB RDS, you must create a database in the ApsaraDB RDS for MySQL instance before you configure the migration task. For more information about the database naming conventions and how to create a database for an RDS instance, see Create a database.

Billing rules

Migration types

• Schema migration

  DTS supports schema migration for tables and indexes. DTS does not support schema migration for the following types of objects: views, synonyms, triggers, stored procedures, stored functions, packages, and user-defined data types. DTS has the following limits on schema migration for tables and indexes:

  • DTS does not support schema migration for nested tables. DTS converts clustered tables and index-organized tables into standard tables in the destination database.

  • DTS does not support schema migration for function-based indexes, domain indexes, bitmap indexes, or reverse indexes.

• Full data migration

  DTS migrates the historical data of specified objects from the self-managed Oracle database to the destination database in the RDS instance.

• Incremental data migration

  DTS uses the round-robin algorithm to retrieve redo log files from the self-managed Oracle database. Then, DTS synchronizes incremental data from the self-managed Oracle database to the destination database in the RDS instance. Incremental data migration ensures service continuity when you migrate data from the self-managed Oracle database to the destination database in the RDS instance.

SQL operations that can be migrated during incremental data migration

• INSERT, DELETE, and UPDATE

• CREATE TABLE

  Note

  If a CREATE TABLE statement creates a table that contains functions, DTS does not migrate the statement.

• ALTER TABLE, ADD COLUMN, DROP COLUMN, RENAME COLUMN, and ADD INDEX

• DROP TABLE

• RENAME TABLE, TRUNCATE TABLE, and CREATE INDEX

Data type mappings

For more information, see Data type mappings between heterogeneous databases.

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 an account and grant permissions to the account, see the following topics:

• Self-managed Oracle database: CREATE USER and GRANT

• ApsaraDB RDS for MySQL instance: Create an account on an ApsaraDB RDS for MySQL instance and Modify the permissions of a standard account on an ApsaraDB RDS for MySQL instance.

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. In the upper part of the Migration Tasks page, select the region in which the RDS instance resides.

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

5. Configure the self-managed Oracle database and the RDS instance.

   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. You do not need to specify a unique task name.
   Source Database	Instance Type	The instance type 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 of the source database. 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 endpoint that is used to connect to the self-managed Oracle database. In this example, the public IP address of the database is used.
   	Port Number	The port number that is used to connect to the self-managed Oracle database. The port must be accessible over the Internet. Default value: 1521.
   	Instance Type	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.
   	Database Account	The account of the self-managed Oracle database. For more 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 RDS Instance.
   	Instance Region	The region in which the RDS instance resides.
   	RDS Instance ID	The ID of the RDS instance.
   	Database Account	The database account of the RDS instance. For more 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	If you want 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, make sure that no data is written to the self-managed Oracle database during full data migration. This ensures data consistency between the self-managed Oracle database and the RDS instance.
   Select the objects to be migrated	Select the objects that you want to migrate from the Objects section and click the icon to move the objects to the Selected section. Note You can select columns, tables, or databases as the objects to be migrated. By default, the name of an object that is migrated to the RDS instance remains the same as that in the self-managed Oracle database. You can use the object name mapping feature to rename the objects that are migrated to the ApsaraDB RDS for MySQL instance. For more information, see Object name mapping.
   Specify whether to rename objects	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.
   Specify the retry time range for failed connections to the self-managed Oracle database or ApsaraDB RDS for MySQL instance	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 change tracking task fails. Note When DTS attempts to re-establish a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business needs. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.

8. Click Precheck.

   Note

   • A precheck is performed before the migration task starts. The migration task only starts after the precheck succeeds.

   • If the precheck fails, click the icon next to each failed check item to view the related details. Fix the issues as instructed and run the precheck again.

9. Click Next.

10. In the Confirm Settings dialog box, configure the Channel Specification parameter. Then, read and select Data Transmission Service (Pay-as-you-go) Service Terms.

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

    • Full data migration

      Do not manually stop a full data migration task. If you manually stop a full data migration task, the data that is migrated to the RDS instance may be incomplete. You can wait until the data migration task automatically stops.

    • Incremental data migration

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

      Note

      We recommend that you manually stop an incremental data migration task at an appropriate point in time. For example, you can stop the task during off-peak hours or before you switch your workloads over to the ApsaraDB RDS for MySQL instance.

      1. Wait until Incremental Data Migration and The data migration task is not delayed are displayed in the progress bar of the data 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 data migration task is not delayed again. Then, manually stop the migration task.

12. Switch your workloads over to the RDS instance.

What to do next

The accounts that are used to migrate data are granted the read and write permissions. After the data migration is complete, you must delete the accounts of the self-managed Oracle database and the ApsaraDB RDS for MySQL instance to ensure database security.

References

DTS supports reverse data synchronization when you migrate data from a self-managed Oracle database to an ApsaraDB RDS for MySQL instance. You can use this feature to synchronize data changes generated in the ApsaraDB RDS for MySQL instance back to the self-managed Oracle database.