Migrate data between self-managed Oracle databases

Precautions

• 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 database, stop or release the data migration task. Otherwise, the data in the source database will overwrite the data in the destination database after the task is resumed.

Billing

Migration types

Permissions required for database accounts

For more information about how to create and authorize an Oracle database account, see CREATE USER and GRANT.

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: 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 Enable minimal supplemental logging: alter database add supplemental log data; 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 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 ;

2. Grant fine-grained permissions to an Oracle database account
   Oracle Versions 9i to 11g Oracle Versions 12c to 19c (Multitenant Architecture) Oracle Versions 12c to 19c (Non-Multitenant Architecture)

   # 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

The procedure in this topic uses a self-managed database hosted on ECS as an example. You can also follow the procedure to configure data migration tasks for other types of self-managed Oracle databases.

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 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	DTS automatically generates a task name. We recommend that you specify an informative name to identify the task. You do not need to use a unique task name.
   Source Database	Instance Type	Select User-Created Database in ECS Instance. 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	Select the region of the Elastic Compute Service (ECS) instance on which the source Oracle database is deployed.
   	ECS Instance ID	Select the ID of the ECS instance on which the source Oracle database is deployed.
   	Database Type	Select Oracle.
   	Port Number	Enter the service port number of the source Oracle database.
   	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 source Oracle database. For information about the permissions that are required for the account, see Permissions required for database accounts.
   	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 User-Created Database in ECS Instance.
   	Instance Region	Select the region of the ECS instance on which the destination Oracle database is deployed.
   	ECS Instance ID	Select the ID of the ECS instance on which the destination Oracle database is deployed.
   	Database Type	Select Oracle.
   	Port Number	Enter the service port number of the destination Oracle database.
   	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 destination Oracle database. For information about the permissions that are required for the account, see Permissions required for database accounts.
   	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.
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, do not write data to the source Oracle database during full data migration. This ensures data consistency between the source and destination databases. For more information, see Migration types.
   Select the objects to be migrated	Select one or more objects from the Available 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, after an object is migrated to the destination Oracle database, the name of the object remains the same as that in the source Oracle database. You can use the object name mapping feature to rename the objects that are migrated to the destination Oracle 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 database. 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. In the lower-right corner of the page, click Precheck.
   Note

   • Before you can start the data migration task, a precheck is performed. 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 will be incomplete. You can wait until the data migration task automatically stops.

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

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

      Notice 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 delay time 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.