Apsara PolarDB is a next-generation relational database service developed by Alibaba Cloud. It is compatible with MySQL, PostgreSQL, and Oracle database engines. The superior performance of Apsara PolarDB in storage and computing meets diverse requirements of enterprises. This topic describes how to migrate data from a user-created Oracle database to a PolarDB cluster compatible with Oracle by using Data Transmission Service (DTS).
Prerequisites
- The version of the user-created Oracle database is 9i, 10g, 11g, 12c, 18c, or 19c.
- The ARCHIVELOG mode is enabled for the user-created Oracle database. 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 user-created Oracle database. For more information, see Supplemental Logging.
- The tables to be migrated from the user-created Oracle database contain primary keys or UNIQUE NOT NULL indexes.
Precautions
- DTS uses read and write resources of the source and destination databases during full data migration. This may increase the database load. 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 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 usage of the source and destination databases is less than 30%.
- DTS automatically resumes a failed data migration 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 type | Instance configurations | Internet traffic |
---|---|---|
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
Migration type | Description |
---|---|
Schema migration | DTS migrates the schemas of the required objects to the destination database. DTS
supports schema migration for the following types of objects: table, view, synonym,
trigger, stored procedure, function, package, and user-defined type.
Note However, if an object contains triggers, the data between the source and destination
databases will become inconsistent.
|
Full data migration | DTS migrates historical data of the required objects from the user-created Oracle
database to the destination PolarDB cluster.
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 | DTS retrieves redo log files from the user-created Oracle database. Then, DTS synchronizes incremental data from the user-created Oracle database to the destination PolarDB cluster. Incremental data migration allows you to ensure service continuity when you migrate data from the user-created Oracle database to the destination PolarDB cluster. |
SQL operations that can be synchronized during incremental data migration
- INSERT, UPDATE, and DELETE operations
- CREATE TABLE operations
Note The CREATE TABLE operations to create partition tables or tables that contain functions cannot be synchronized.
- ALTER TABLE, DROP TABLE, RENAME TABLE, CREATE INDEX, and ADD INDEX operations
Preparations
Log on to the source Oracle database, create an account for data collection, and grant permissions to the account.
Database | Schema migration | Full data migration | Incremental data migration |
---|---|---|---|
User-created Oracle database | The owner permission on schemas | The owner permission on schemas | The database administrator (DBA) permission |
PolarDB cluster | The owner permission on schemas | The owner permission on schemas | The owner permission on schemas |
For more information about how to create and authorize a database account, see the following topics:
- CREATE USER and GRANT for a user-created Oracle database
- Create an account for a PolarDB cluster
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_$listener_network to dtstest;
#The following sample statements show you how to grant permissions on the pluggable database (PDB) and container database (CDB) to a database account named dtstest. #Grant permissions on the PDB: create user dtstest IDENTIFIED BY rdsdt_dtsacct; grant create session to dtstest; grant connect to dtstest; grant resource to dtstest; grant select on all_objects to dtstest; grant select on all_tab_cols to dtstest; grant select on dba_registry to dtstest; grant select any table to dtstest; grant select any transaction to dtstest; -- v$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;