Migrate data from a self-managed Oracle database to a PolarDB-O cluster

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%.
• 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 from the source database will overwrite the data in the destination database after the task is resumed.
• If the version of your Oracle database is 12c or later, the names of the tables to be migrated cannot exceed 30 bytes in length.

Billing

Migration types

Before you begin

Log on to the source Oracle database, create an account for data collection, and grant permissions to the account.

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

• Self-managed Oracle database: CREATE USER and GRANT
• PolarDB cluster: Create an account

create session;
connect;
resource;
execute on sys.dbms_logmnr;
select on v_$logmnr_contents;
select on v_$log;
select on v_$logfile;
select on v_$archived_log;
select on v_$logmnr_logs;
select on v_$parameter;
select on v_$database;
select on all_objects;
select on all_tab_cols;
select on dba_registry;
select any table;
select any transaction;
select on v$active_instances;
select on v$instance;
select on sys.USER$;
select on SYS.OBJ$;
select on SYS.COL$;
select on SYS.IND$;
select on SYS.ICOL$;
select on SYS.CDEF$;
select on SYS.CCOL$;
select on SYS.TABPART$;
select on SYS.TABSUBPART$;
select on SYS.TABCOMPART$;
select on gv_$listener_network;

# Grant permissions on the pluggable database (PDB) and container database (CDB).
# Grant permissions on the PDB:
create   session;
connect;
resource;
select on  all_objects;
select on  all_tab_cols;
select on  dba_registry;
select any table;
select any transaction;
select on v_$log;
select on v_$logfile;
select on v_$archived_log;
select on v_$parameter;
select on v_$database;
select on v_$active_instances;
select on v_$instance;
select on V_$PDBS;
select on sys.USER$;
select on SYS.OBJ$;
select on SYS.COL$;
select on SYS.IND$;
select on SYS.ICOL$;
select on SYS.CDEF$;
select on SYS.CCOL$;
select on SYS.TABPART$;
select on SYS.TABSUBPART$;
select on SYS.TABCOMPART$;

# Grant permissions on the CDB:
create   session;
LOGMINING;
select on v_$logmnr_contents;

# The following sample statements show you how to grant permissions to a database account named dtstest.
create user dtstest IDENTIFIED BY rdsdt_dtsacct;
grant create session to dtstest;
grant connect to dtstest;
grant resource to dtstest;
grant execute on sys.dbms_logmnr to dtstest;
grant select on v_$logmnr_contents to dtstest;
grant select on v_$log to dtstest;
grant select on v_$logfile to dtstest;
grant select on v_$archived_log to dtstest;
grant select on v_$logmnr_logs to dtstest;
grant select on v_$parameter to dtstest;
grant select on v_$database to dtstest;
grant select on all_objects to dtstest;
grant select on all_tab_cols to dtstest;
grant select on dba_registry to dtstest;
grant select any table to dtstest;
grant select any transaction to dtstest;
grant select on v$active_instances to dtstest;
grant select on v$instance to dtstest;
grant select on sys.USER$ to dtstest;
grant select on SYS.OBJ$ to dtstest;
grant select on SYS.COL$ to dtstest;
grant select on SYS.IND$ to dtstest;
grant select on SYS.ICOL$ to dtstest;
grant select on SYS.CDEF$ to dtstest;
grant select on SYS.CCOL$ to dtstest;
grant select on SYS.TABPART$ to dtstest;
grant select on SYS.TABSUBPART$ to dtstest;
grant select on SYS.TABCOMPART$ to dtstest;
grant select on gv_$listener_network to dtstest;

# The following sample statements show you how to grant permissions on the PDB and CDB to a database account named dtstest.
# Grant permissions on the PDB:
create user dtstest IDENTIFIED BY rdsdt_dtsacct;
grant create  session to dtstest;
grant connect  to dtstest;
grant resource to dtstest;
grant select on  all_objects to dtstest;
grant select on  all_tab_cols to dtstest;
grant select on  dba_registry to dtstest;
grant select any table to dtstest;
grant select any transaction to dtstest;
-- v$log privileges
grant select on v_$log to dtstest;
-- v$logfile privileges
grant select on v_$logfile to dtstest;
-- v$archived_log privileges
grant select on v_$archived_log to dtstest;
-- v$parameter privileges
grant select on v_$parameter to dtstest;
-- v$database privileges
grant select on v_$database to dtstest;
-- v$active_instances privileges
grant select on v_$active_instances to dtstest;
-- v$instance privileges
grant select on v_$instance to dtstest;
-- V$PDBS privileges
grant select on V_$PDBS to dtstest;
grant select on sys.USER$ to dtstest;
grant select on SYS.OBJ$ to dtstest;
grant select on SYS.COL$ to dtstest;
grant select on SYS.IND$ to dtstest;
grant select on SYS.ICOL$ to dtstest;
grant select on SYS.CDEF$ to dtstest;
grant select on SYS.CCOL$ to dtstest;
grant select on SYS.TABPART$ to dtstest;
grant select on SYS.TABSUBPART$ to dtstest;
grant select on SYS.TABCOMPART$ to dtstest;

# Grant permissions on the CDB:
create user dtstest IDENTIFIED BY rdsdt_dtsacct;
grant create   session to dtstest;
grant LOGMINING TO dtstest;
-- v$logmnr_contents privileges
grant select on v_$logmnr_contents to dtstest;

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 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 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 the instance type is set to User-Created Database with Public IP Address, 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. Note The service port of the self-managed Oracle database must be accessible over the Internet.
   	Instance Type	Non-RAC Instance: If you select this option, you must specify the SID parameter. RAC Instance: If you select this option, 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 PolarDB.
   	Instance Region	Select the region where the destination PolarDB cluster resides.
   	PolarDB Instance ID	Select the ID of the destination PolarDB cluster.
   	Database Name	Enter the name of the destination database.
   	Database Account	Enter the database account of the destination PolarDB cluster. 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 PolarDB cluster. This ensures that DTS servers can connect to the destination PolarDB cluster.
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 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 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 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.
12. Switch your workloads to the destination PolarDB cluster.