This topic describes how to migrate data from a self-managed Oracle database to a DRDS instance by using Data Transmission Service (DTS). DTS supports full data migration and incremental data migration. When you migrate data from a self-managed Oracle database, you can select the two migration types to ensure service continuity.

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 service port of the self-managed Oracle database is accessible over the Internet.
  • The databases in the DRDS instance are created based on ApsaraDB RDS for MySQL instances. DTS does not support DRDS databases that are created based on PolarDB for MySQL clusters.
  • The available storage space of the RDS instances in the DRDS instance is larger than the total size of the data in the self-managed Oracle database.

Precautions

  • DTS does not support schema migration from a self-managed Oracle database to a DRDS instance.
    Note During schema migration, DTS migrates the schemas of the required objects, such as tables, from the source database to the destination database.
  • 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 a data migration task fails, DTS automatically resumes the task. Before you switch your workloads to the destination instance, stop or release the data migration task. Otherwise, the data in the source database will overwrite the data in the destination instance after the task is resumed.

Billing

Migration type Task configuration fee Internet traffic fee
Schema migration and full data migration Free of charge. Charged only when data is migrated from Alibaba Cloud over the Internet. For more information, see Pricing.
Incremental data migration Charged. For more information, see Pricing.

Migration types

  • Full data migration
    DTS migrates historical data of the required objects from the self-managed Oracle database to the destination database in the DRDS instance.
    Note To ensure data consistency, we recommend that you do not write data to the self-managed Oracle database during full data migration.
  • Incremental data migration
    After full data migration is complete, DTS retrieves 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 DRDS instance. Incremental data migration allows you to ensure service continuity when you migrate data from the self-managed Oracle database to the DRDS instance.
    Note The following SQL operations can be synchronized during incremental data migration: INSERT, DELETE, and UPDATE operations. Data definition language (DDL) operations cannot be synchronized during incremental data migration.

Before you begin

  1. Create a database and tables in the destination DRDS instance based on the schema of the self-managed Oracle database. For more information, see Create a DRDS database and Create a DRDS table.
    Note The data types of an Oracle databases and a DRDS instance do not have one-to-one correspondence. You must define the corresponding data types in the DRDS instance. For more information, see Data type mappings between heterogeneous databases.
  2. Log on to the source Oracle database, create an account for data collection, and grant permissions to the account.
    Database Full data migration Incremental data migration
    Self-managed Oracle database The permissions of the schema owner The database administrator (DBA) permission
    DRDS The write permissions on the destination database The write permissions on the destination database

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

Notice If you need to migrate data from an Oracle database but the database administrator (DBA) permission cannot be granted to the database account, you can enable archive logging and supplemental logging, and grant fine-grained permissions to the 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:
    Note You can enable database-level supplemental logging to ensure the stability of DTS tasks. You can enable table-level supplemental logging to reduce the disk usage of the source Oracle database.
    • Enable database-level supplemental logging
      1. Enable minimal supplemental logging:
        alter database add supplemental log data;
      2. 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
      1. Enable minimal supplemental logging:
        alter database add supplemental log data;
      2. 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 ;
  2. Grant fine-grained permissions to an Oracle database account
    # Create a database account, for example, 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;
    # Switch to the pluggable database (PDB). Create a database account, for example, 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;
    
    # Switch to the container database (CDB). Create a database account and grant permissions to the account by using one of the following methods:
    ALTER SESSION SET container = CDB$ROOT;
    Method 1: Create a global account starting with C##, for example, C##rdsdt_dtsacct, and grant permissions to the account. If you use this method, you must submit a ticket and contact the DTS team to modify some parameters. The link to submit a ticket is provided in the note.
    create user C##rdsdt_dtsacct IDENTIFIED BY rdsdt_dtsacct;
    grant create session to C##rdsdt_dtsacct;
    grant connect to C##rdsdt_dtsacct;
    grant resource to C##rdsdt_dtsacct;
    grant select on v_$logmnr_contents to rdsdt_dtsacct;
    grant LOGMINING to C##rdsdt_dtsacct;
    grant EXECUTE_CATALOG_ROLE to C##rdsdt_dtsacct;
    grant execute on sys.dbms_logmnr to C##rdsdt_dtsacct;
    Method 2: Create a database account, for example, rdsdt_dtsacct, and grant permissions to the account. If you use this method, 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_$logmnr_contents to rdsdt_dtsacct;
    grant LOGMINING TO rdsdt_dtsacct;
    grant EXECUTE_CATALOG_ROLE to rdsdt_dtsacct;
    grant execute on sys.dbms_logmnr to rdsdt_dtsacct;
    # Create a database account, for example, rdsdt_dtsacct, and grant permissions to the account.
    create user rdsdt_dtsacct IDENTIFIED BY rdsdt_dtsacct;
    grant create  session to rdsdt_dtsacct;
    grant connect  to rdsdt_dtsacct;
    grant resource to rdsdt_dtsacct;
    grant select on V_$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;
    -- 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;
    Note To create a global account starting with C## for a multitenant container database (CDB) in Oracle 12c to 19c, you must submit a ticket and contact the DTS team to modify some parameters.

Procedure

  1. Log on to 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 instance resides. Select a region
  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 DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
    Source Database Instance Type Select an instance type based on the deployment of the source database. In this example, select User-Created Database with Public IP Address.
    Note If you select other instance types, you must deploy the network environment for the source database. For more information, see Preparation overview.
    Instance Region 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 a whitelist is configured for the self-managed Oracle database, you must add the CIDR blocks of DTS servers to the 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 Select Oracle.
    Hostname or IP Address Enter the endpoint that is used to connect to the self-managed Oracle database. In this example, enter the public IP address.
    Port Number Enter the service port number of the self-managed Oracle database. The default port number is 1521.
    Instance Type
    • If you select Non-RAC Instance, you must specify the SID parameter.
    • If you select RAC Instance, you must specify the Service Name parameter.
    Database Account Enter the account of the self-managed Oracle database. For information about the permissions that are required for the account, see Before you begin.
    Database Password Enter the password of the database account.
    Note After you specify the source database parameters, click Test Connectivity next to Database Password to verify whether the specified parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the source database parameters based on the check results.
    Destination Database Instance Type Select DRDS Instance.
    Instance Region Select the region where the destination DRDS instance resides.
    DRDS Instance ID Select the ID of the destination DRDS instance.
    Database Account Enter the database account of the destination DRDS instance. For information about the permissions that are required for the account, see Before you begin.
    Database Password Enter the password of the database account.
    Note After you specify the destination database parameters, click Test Connectivity next to Database Password to verify whether the parameters are valid. If the specified parameters are valid, the Passed message appears. If the Failed message appears, click Check next to Failed. Modify the destination database parameters based on the check results.
  6. In the lower-right corner of the page, click Set Whitelist and Next.
    Note DTS adds the CIDR blocks of DTS servers to the whitelist of the destination DRDS instance. This ensures that DTS servers can connect to the destination DRDS instance.
  7. Select the migration types and the objects to be migrated. 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, do not write data to the source database during full data migration. This ensures data consistency between the source and destination databases.
    Select the objects to be migrated

    Select one or more objects from the Available section and click the Rightwards arrow 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, after an object is migrated to the destination RDS instance, the name of the object 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 destination RDS 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 instance. For more information, see Object name mapping.
    Specify the retry time for failed connections to the source or destination database By default, if DTS fails to connect to the source or destination database, DTS retries within the next 12 hours. You can specify the retry time based on your needs. If DTS reconnects to the source and destination databases within the specified time, DTS resumes the data migration task. Otherwise, the data migration task fails.
    Note When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time 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 Note icon next to each failed check item to view the related details. Fix the issues as instructed and run the 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.
    • Full data migration

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

    • Incremental data migration

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

      Note 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 instance.
      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 delay time of incremental data migration may be displayed in the progress bar.
      2. After the status of incremental data migration changes to The migration task is not delayed again, manually stop the migration task. The migration task is not delayed
  12. Switch your workloads to the destination DRDS instance.

What to do next

The database accounts that are used for data migration have the read and write permissions. After data migration is complete, you must delete the accounts of both the self-managed Oracle database and the DRDS instance to ensure security.