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AnalyticDB for PostgreSQL:Migrate data from a self-managed Oracle database to an AnalyticDB for PostgreSQL instance

Last Updated:May 10, 2023

This topic describes how to migrate data from a self-managed Oracle database to an AnalyticDB for PostgreSQL instance by using Data Transmission Service (DTS).

Prerequisites

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

  • 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.

  • 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 destination AnalyticDB for PostgreSQL instance is created. For more information, see Create an AnalyticDB for PostgreSQL instance.

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 Billing overview.

Incremental data migration

Charged. For more information, see Billing overview.

Usage notes

  • During full data migration, DTS uses read and write resources of the source and destination databases. This may increase the loads of the database servers. 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.

  • 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 from the source database overwrites the data in the destination database after the task is resumed.

  • 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 an on-premises 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.

Migration types

Migration type

Description

Schema migration

DTS migrates the schemas of the objects from the source database to the destination database. DTS supports schema migration for the following types of objects: table, index, constraint, function, sequence, and view.

Warning
  • In this topic, the source and destination databases are heterogeneous databases. DTS does not ensure that the schemas of the source and destination databases are consistent after schema migration. We recommend that you evaluate the impact of data type conversion on your business. For more information, see Data type mappings between heterogeneous databases.

  • For partitioned tables, DTS discards the partition definitions. You must define partitions in the destination database.

Full data migration

DTS migrates historical data of the objects from the source database to the destination database.

Note

During schema migration and full data migration, do not perform DDL operations on the objects to be migrated. Otherwise, the objects may fail to be migrated.

Incremental data migration

After full data migration is complete, DTS retrieves redo log files from the source Oracle database. Then, DTS migrates incremental data from the source Oracle database to the destination database in real time.

DTS can migrate the following SQL operations during incremental data migration:

  • DML operations: INSERT, UPDATE, and DELETE

  • DDL operation: ADD COLUMN

Incremental data migration ensures the service continuity of self-managed applications during data migration.

Permissions required for database accounts

Database

Schema migration

Full data migration

Incremental data migration

Self-managed Oracle database

Permissions of the schema owner

Permissions of the schema owner

Database administrator (DBA)

AnalyticDB for PostgreSQL

Read and write permissions on the destination database

Read and write permissions on the destination database

Read and write permissions on the destination database

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

Important

If you need to migrate incremental data from an Oracle database but the DBA permission cannot be granted to the database account, you can grant fine-grained permissions to the account. The following section describes how to grant specific permissions to an Oracle database account.

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

Important

If you need to migrate incremental data from an Oracle database but the DBA permissions 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 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

      1. Execute the following statement to enable minimal supplemental logging:

        alter database add supplemental log data;
      2. 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

      1. Execute the following statement to 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;

    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 old icon in the lower-right corner 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 where the destination instance resides.

  4. In the upper-right corner of the page, click Create Migration Task.
  5. Configure the source and destination databases.

    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. 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 in ECS Instance 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 where the Elastic Compute Service (ECS) instance resides. The self-managed Oracle database is hosted on the ECS instance.

    ECS Instance ID

    The ID of the ECS instance on which the self-managed Oracle database is hosted.

    Database Type

    The type of the source database. Select Oracle.

    Port Number

    The service port number of the self-managed Oracle database. Default value: 1521.

    Instance Type

    • The architecture type of the self-managed Oracle database. 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.

    In this example, Non-RAC Instance is selected.

    SID

    The system ID (SID) of the self-managed Oracle database.

    Database Account

    The account of the self-managed Oracle database. For information about the permissions that are required for the account, see the "Permissions required for database accounts" section of this topic.

    Database Password

    The password of the database account.

    Note

    After you specify the information about the self-managed Oracle 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 type of the destination database. Select AnalyticDB for PostgreSQL.

    Instance Region

    The region where the destination AnalyticDB for PostgreSQL instance resides.

    Instance ID

    The ID of the destination AnalyticDB for PostgreSQL instance.

    Database Name

    The name of the destination database.

    Database Account

    The database account of the destination AnalyticDB for PostgreSQL instance. For information about the permissions that are required for the account, see the "Permissions required for database accounts" section of this topic.

    Database Password

    The password of the database account.

  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, the operation 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, 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.

    Select the operation types

    Select the types of operations that you want to migrate during incremental data migration. By default, all operation types are selected.

    Select the objects to be migrated

    Select one or more objects from the Available section and click the Rightwards arrow icon to add the objects to the Selected section.

    Note
    • You can select columns, tables, or schemas 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.

    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.

    Enclose object names in quotation marks

    Specifies whether to enclose object names in quotation marks. If you select Yes and the following conditions are met, DTS encloses object names in single quotation marks (') or double quotation marks (") during schema migration and incremental data migration.

    • The business environment of the source database is case-sensitive, and the database name contains both uppercase and lowercase letters.

    • A source table name does not start with a letter and contains characters other than letters, digits, and special characters.

      Note

      A source table name can contain only the following special characters: underscores (_), number signs (#), and dollar signs ($).

    • The names of the schemas, tables, or columns that you want to synchronize are keywords of the destination database, reserved keywords, or invalid characters.

  8. Specify the primary key columns and distribution keys of the tables that you want to migrate to the AnalyticDB for PostgreSQL instance.

    Advanced settings: Migrate Oracle to AnalyticDB for PostgreSQL
    Note
    • For more information about primary key columns and distribution keys, see Define constraints and Define table distribution.

    • If DTS identifies tables without primary keys, the option Set Primary Keys and Distribution Keys of All Tables Without Primary Keys to ROWID is displayed on the preceding page. If you select this option, DTS adds the ROWID field as the primary key and distribution key to the destination tables.

  9. 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 Info icon 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.
  10. After the task passes the precheck, click Next.
  11. In the Confirm Settings dialog box, specify the Channel Specification parameter and select Data Transmission Service (Pay-As-You-Go) Service Terms.
  12. 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. Stop an incremental data migration task