Synchronize self-managed Oracle to AnalyticDB for PostgreSQL-AnalyticDB(AnalyticDB)-阿里云帮助中心

DTS synchronizes data from a self-managed Oracle database to an AnalyticDB for PostgreSQL instance, enabling you to build a real-time data warehouse.

Prerequisites

The self-managed Oracle database is version 9i, 10g, 11g, 12c, 18c, or 19c.
The self-managed Oracle database runs in ARCHIVELOG mode, and its archived logs have a reasonable retention period and are accessible. For more information, see ARCHIVELOG.
Supplemental logging, including supplemental_log_data_pk and supplemental_log_data_ui, is enabled. For more information, see Supplemental Logging.
A destination AnalyticDB for PostgreSQL instance is available. For creation instructions, see Create an instance.
Before you synchronize an Oracle source database, understand the capabilities and limitations of Data Transmission Service (DTS) and use Advanced Database & Application Migration (ADAM) to assess your database. This ensures a smooth migration to the cloud. For more information, see Limitations and preparation for Oracle databases and Database assessment overview.

Usage notes

Note

During schema synchronization, DTS synchronizes foreign keys from the source database to the destination database.
During full data synchronization and incremental data synchronization, DTS temporarily disables constraint checks and foreign key cascade operations at the session level. Data inconsistency may occur if cascade update or delete operations are performed on the source database while the task is running.

Category	Description
Limits on the source database	Requirements for the objects to be synchronized: The tables to be synchronized must have PRIMARY KEY or UNIQUE constraints, and all fields must be unique. Otherwise, the destination database may contain duplicate data records. If the version of your Oracle database is 12c or later, the names of the tables to be synchronized cannot exceed 30 bytes in length. If you select tables as the objects to be synchronized and you want to edit the tables in the destination database, such as renaming tables or columns, you can synchronize up to 1,000 tables in a single data synchronization task. If you run a task to synchronize more than 1,000 tables, a request error occurs. In this case, we recommend that you split the tables and configure multiple tasks to synchronize the tables in batches or configure a task to synchronize the entire database. If the source database is an Oracle Real Application Cluster (RAC) database connected over Express Connect, you must specify a virtual IP address (VIP) for the database when you configure the data synchronization task. If the self-managed Oracle database is an Oracle RAC database, you can only use a VIP rather than a Single Client Access Name (SCAN) IP address when you configure the data synchronization task. After you specify the VIP, node failover of the Oracle RAC database is not supported. The redo logging and archive logging features must be enabled. Note If you perform only incremental data synchronization, the redo logs and archive logs of the source database must be stored for more than 24 hours. If you perform both full data synchronization and incremental data synchronization, the redo logs and archive logs of the source database must be stored for at least seven days. Otherwise, DTS may fail to obtain the redo logs and archive logs and the task may fail. In exceptional circumstances, data inconsistency or loss may occur. After the full data synchronization is complete, you can set the retention period to more than 24 hours. Make sure that you set the retention period of redo logs and archive logs in accordance with the preceding requirements. Otherwise, the service reliability and performance stated in the Service Level Agreement (SLA) of DTS may not be guaranteed. If you perform a primary/secondary switchover on the source database when the data synchronization task is running, the task fails. If the data to be synchronized contains an empty string of the VARCHAR2 type (Oracle processes it as null) and the corresponding column in the destination database has a NOT NULL constraint, the data synchronization task fails. If the table to be synchronized has the Fine-Grained Audit (FGA) policy enabled, DTS cannot detect the `ORA_ROWSCN` pseudocolumn, which causes the synchronization task to fail. Note You can disable the FGA policy for the table to be synchronized, or exclude the table from synchronization. During data synchronization, do not update LONGTEXT fields. Otherwise, the data synchronization task fails. Do not run DDL operations that change database or table schemas during schema synchronization or full synchronization. Otherwise, the synchronization task fails. Note During full synchronization, DTS queries the source database. This creates metadata locks that may block DDL operations on the source database.
Other limits	DTS supports initial schema synchronization for the following types of objects: table, constraint, function, sequence, and view. Warning DTS does not ensure that the schemas of the source and destination databases are consistent after initial schema synchronization. We recommend that you evaluate the impact of data type conversion on your business. Otherwise, the data synchronization task may fail, or data inconsistency may occur. For more information, see Data type mappings for schema synchronization. External tables cannot be synchronized. Packages, package bodies, materialized views, synonyms, types, type bodies, procedures, and indexes cannot be synchronized. Triggers cannot be synchronized. We recommend that you delete the triggers of the source database to prevent data inconsistency caused by triggers. For more information about how to synchronize triggers, see Configure a data synchronization or migration task for a source database that contains a trigger. For partitioned tables, DTS discards the partition definitions. You must define partitions in the destination database. You can select only tables as the objects to be synchronized. The tables cannot be append-optimized (AO) tables. If column mapping is used for non-full table synchronization or if the source and destination table structures are inconsistent, the data for the columns that are missing in the destination database compared to the source database will be lost. The destination AnalyticDB for PostgreSQL instance does not support the string terminator '\0'. If the data to be synchronized contains the terminator, DTS does not write the terminator to the destination database. This causes data inconsistency between the source and destination databases. During incremental data synchronization, you cannot use Oracle Data Pump to write data to the source database. Otherwise, data loss may occur. Before you synchronize data, evaluate the impact of data synchronization on the performance of the source and destination databases. We recommend that you synchronize data during off-peak hours. During initial full data synchronization, DTS uses the read and write resources of the source and destination databases. This may increase the loads on the database servers. During full data synchronization, concurrent INSERT operations cause fragmentation in the tables of the destination database. After the full data synchronization is complete, the size of the used tablespace of the destination database is larger than that of the source database. DTS calculates synchronization latency based on the timestamp of the latest synchronized data in the destination database and the current timestamp in the source database. If no DML operation is performed on the source database for a long time, the synchronization latency may be inaccurate. If the latency of the synchronization task is excessively high, you can perform a DML operation on the source database to update the latency. Note If you select an entire database as the object to synchronize, you can create a heartbeat table. The heartbeat table is updated or receives data every second. During data synchronization, use only DTS to write data to the destination database. This prevents data inconsistency between the source and destination databases. For example, if you use tools other than DTS to write data to the destination database, data loss may occur in the destination database when you use Data Management (DMS) to perform online DDL operations. If a task fails, DTS support staff will attempt to restore it within eight hours. During restoration, they may restart the task or adjust its parameters. Note Only DTS task parameters are modified—not database parameters. Parameters that may be adjusted include those listed in Modify instance parameters.

Billing

Synchronization type	Pricing
Schema synchronization and full data synchronization	Free of charge.
Incremental data synchronization	Charged. For more information, see Billing overview.

Synchronization topologies

One-way one-to-one synchronization
One-way one-to-many synchronization
One-way many-to-one synchronization
One-way cascade synchronization

For more information about these synchronization topologies, see Data synchronization topologies.

Supported SQL operations

Operation type	SQL statement
DML	INSERT, UPDATE, and DELETE Note The system automatically converts UPDATE statements to REPLACE INTO statements when writing data to a destination AnalyticDB for PostgreSQL instance. If an UPDATE statement modifies a primary key, the system instead converts it into a DELETE statement and an INSERT statement.
DDL	ADD COLUMN

Database account permissions

Database	Permissions	Account setup
Self-managed Oracle database	Requires fine-grained permissions.	Prepare a database account, CREATE USER, and GRANT.
AnalyticDB for PostgreSQL instance	Write permissions on the destination database.	The initial account for the destination AnalyticDB for PostgreSQL instance has the required permissions. To create an account, see Create a database account. Note You can also use an account with the `RDS_SUPERUSER` permission. To create the account, see Manage users and permissions.

Important

You must also enable archive logs and supplemental logging to capture incremental data changes. For more information, see Database configuration.

Procedure

Go to the Data Synchronization Tasks page.
1. Log on to the DMS console.
2. In the top navigation bar, click Data + AI.
3. In the left-side navigation pane, choose DTS (DTS) > Data Synchronization.
Note
- Operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode console and Customize the layout and style of the DMS console.
- You can also go to the Data Synchronization Tasks page of the new DTS console.

Click Create Task to configure the source and destination databases.

Category	Parameter	Description
N/A	Task Name	DTS automatically generates a task name. We recommend that you specify a descriptive name for easy identification. The name does not need to be unique.
Source Database	Database Type	Select Oracle.
	Connection Type	Select a connection type based on the deployment location of the source database. This topic uses Self-managed Database on ECS as an example. Note If the source database is a self-managed database, you must also perform the required preparations. For more information, see Preparation overview.
	Instance Region	Select the region where the self-managed Oracle database is located.
	ECS Instance ID	Select the instance ID of the ECS instance that hosts the self-managed Oracle database.
	Port	Enter the service port of the self-managed Oracle database. The default value is 1521.
	Oracle Type	Non-RAC Instance: If you select this option, you must also specify the SID. RAC or PDB Instance: If you select this option, you must also specify the Service Name. In this example, Non-RAC Instance is selected.
	Database Account	Enter the database account of the self-managed Oracle database. For more information about the required permissions, see Permissions for database accounts.
	Database Password	Enter the password for the specified database account.
Destination Database	Database Type	Select AnalyticDB for PostgreSQL.
	Connection Type	Select Alibaba Cloud Instance.
	Instance Region	Select the region where the destination AnalyticDB for PostgreSQL instance is located.
	Instance ID	Select the instance ID of the destination AnalyticDB for PostgreSQL instance.
	Database Name	Enter the name of the destination database in the AnalyticDB for PostgreSQL instance that will contain the synchronized objects.
	Database Account	Enter the database account of the destination AnalyticDB for PostgreSQL instance. For more information about the required permissions, see Permissions for database accounts.
	Database Password	Enter the password for the specified database account.

After completing the configuration, click Test Connection and Proceed at the bottom of the page.
If the source or destination database is an Alibaba Cloud database instance, such as an RDS for MySQL instance or an ApsaraDB for MongoDB instance, DTS automatically adds the IP address of the DTS service for the corresponding region to the whitelist of the Alibaba Cloud database instance. If the source or destination database is a self-managed database on an ECS instance, DTS automatically adds the IP address of the DTS service for the corresponding region to the security rules of the ECS instance. You must also ensure that the self-managed database does not restrict access from the ECS instance. If the database is deployed in a cluster on multiple ECS instances, you must manually add the IP address of the DTS service for the corresponding region to the security rules of each of the other ECS instances. If the source or destination database is a self-managed database in an IDC or a database from another cloud provider, you must manually add the IP address of the DTS service for the corresponding region to allow access from the DTS servers. For more information about the IP addresses of the DTS service, see IP address blocks of DTS servers.
Warning
Adding the public IP address blocks of the DTS service, either automatically or manually, may pose security risks. Using this product, you acknowledge that you understand and accept the potential security risks and that you must implement basic security measures. These measures include, but are not limited to, strengthening password security, limiting the ports open to each CIDR block, using authentication for internal API calls, and regularly checking and restricting unnecessary CIDR blocks. Alternatively, you can connect through a private network using a leased line, VPN Gateway, or Smart Access Gateway.

Configure the synchronization objects and advanced settings.

Parameter	Description
Synchronization Types	DTS always selects Incremental Data Synchronization. By default, you must also select Schema Synchronization and Full Data Synchronization. After the precheck, DTS initializes the destination cluster with the full data of the selected source objects, which serves as the baseline for subsequent incremental synchronization.
Processing Mode for Existing Destination Tables	Precheck and Report Errors: Checks for tables with the same names in the destination database. If any tables with the same names are found, an error is reported during the precheck and the data synchronization task does not start. Otherwise, the precheck is successful. Note If you cannot delete or rename the table with the same name in the destination database, you can map it to a different name in the destination. For more information, see Database Table Column Name Mapping. Ignore Errors and Proceed: Skips the check for tables with the same name in the destination database. Warning Selecting Ignore Errors and Proceed may cause data inconsistency and put your business at risk. For example: If the table schemas are consistent and a record in the destination database has the same primary key or unique key value as a record in the source database: During full data synchronization, DTS retains the destination record and skips the source record. During incremental synchronization, DTS overwrites the destination record with the source record. If the table schemas are inconsistent, data initialization may fail. This can result in only partial data synchronization or a complete synchronization failure. Use with caution.
Table Merging	Select Yes: In online transactional processing (TP) scenarios, sharding is often used to improve the response speed of business tables. In online analytical processing (OLAP) scenarios, a single table in the destination database can store large volumes of data, which simplifies single-table queries. In such scenarios, you can use the DTS table merging feature to synchronize multiple tables with the same schema (sharded tables) from the source database to a single table in the destination database. For details on this operation, see Enable table merging. Note After you select multiple tables from the source database, you must use the object name mapping feature to change their names to the same table name in the destination database. For more information about the object name mapping feature, see Database Table Column Name Mapping. DTS adds a `__dts_data_source` column of the TEXT type to the destination table to store the data source. The column value is written in the `DTS instance ID:database name:schema name:table name` format to distinguish the source of the table, for example, `dts******:dtstestdata:testschema:customer1`. The table merging feature applies at the task level, not the table level. To merge only some tables, you must create a separate data synchronization task for them. Warning** Do not perform DDL operations that change the database or table schema in the source database. Otherwise, data inconsistency or task failure may occur. No: This is the default option.
Select DDL and DML for Instance-Level Synchronization	Select the DDL or DML operations to synchronize at the instance level. For a list of supported operations, see Supported SQL operations. Note To select SQL operations for a database or table, right-click a synchronization object in the Selected Objects box and select the SQL operations from the dialog box that appears.
Storage Engine Type	Select the storage engine type for the destination tables. The default value is Beam. Note This parameter is available only when the kernel version of the destination AnalyticDB for PostgreSQL instance is v7.0.6.6 or later, and Synchronization Types is selected for Schema Synchronization.
Source Objects	In the Source Objects box, click the objects, and then click to move them to the Selected Objects box. Note You can select objects at the table level.
Selected Objects	To rename a single object in the destination instance, right-click the object in the Selected Objects box. For more information, see Map a single object name. To rename multiple objects in bulk, click Batch Edit in the upper-right corner of the Selected Objects box. For more information, see Map multiple object names in bulk. Note To select SQL operations at the database or table level, right-click a synchronization object in the Selected Objects list and select the desired SQL operations in the dialog box that appears. For a list of supported operations, see Supported SQL operations. To filter data, right-click a table to be synchronized in the Selected Objects list and specify a filter condition in the dialog box that appears. For more information, see Set filter conditions. Object name mapping may cause synchronization failures for objects that depend on the mapped object.

Click Next: Advanced Settings to proceed to the advanced settings.

Data Verification Settings

To use the data validation feature, see Configure data validation.

Advanced Settings

Parameter	Description
Dedicated Cluster for Task Scheduling	By default, DTS uses a shared cluster for tasks, so you do not need to make a selection. For greater task stability, you can purchase a dedicated cluster to run the DTS synchronization task. For more information, see What is a DTS dedicated cluster?.
Enclose Object Names in Quotation Marks	You can choose whether to add quotation marks to destination object names. If you select Yes, DTS adds single or double quotation marks to the destination objects during initial schema synchronization and incremental data synchronization if any of the following conditions are met: The business environment of the source database is case-sensitive and uses mixed case. The source table name does not start with a letter and contains characters other than letters, numbers, or special characters. Note Only the following special characters are supported: underscore (_), number sign (#), and dollar sign ($). The name of the schema, table, or column to be synchronized is a keyword, reserved word, or invalid character in the destination database. Note If you choose to add quotation marks, you must use the quoted destination object name for queries after the data synchronization task is complete.
Retry Time for Failed Connections	If the connection to the source or destination database fails after the synchronization task starts, DTS reports an error and immediately begins to retry the connection. The default retry duration is 720 minutes. You can customize the retry time to a value from 10 to 1,440 minutes. We recommend a duration of 30 minutes or more. If the connection is restored within this period, the task resumes automatically. Otherwise, the task fails. Note If multiple DTS instances (e.g., Instance A and B) share a source or destination, DTS uses the shortest configured retry duration (e.g., 30 minutes for A, 60 for B, so 30 minutes is used) for all instances. DTS charges for task runtime during connection retries. Set a custom duration based on your business needs, or release the DTS instance promptly after you release the source/destination instances.
Retry Time for Other Issues	If a non-connection issue (e.g., a DDL or DML execution error) occurs, DTS reports an error and immediately retries the operation. The default retry duration is 10 minutes. You can also customize the retry time to a value from 1 to 1,440 minutes. We recommend a duration of 10 minutes or more. If the related operations succeed within the set retry time, the synchronization task automatically resumes. Otherwise, the task fails. Important The value of Retry Time for Other Issues must be less than that of Retry Time for Failed Connections.
Enable Throttling for Full Data Synchronization	During full data synchronization, DTS consumes read and write resources from the source and destination databases, which can increase their load. To mitigate pressure on the destination database, you can limit the migration rate by setting Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s). Note This parameter is available only if Synchronization Types is set to Full Data Synchronization. You can also adjust the rate of full data synchronization when the synchronization instance is running.
Enable Throttling for Incremental Data Synchronization	You can also limit the incremental synchronization rate to reduce pressure on the destination database by setting RPS of Incremental Data Synchronization and Data synchronization speed for incremental synchronization (MB/s).
Environment Tag	You can select a tag to identify the environment of the instance. In this example, no tag is needed.
Actual Write Code	You can select the encoding type for data written to the destination based on your requirements.
Configure ETL	Choose whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: Enables the ETL feature. Enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: Disables the ETL feature.
Monitoring and Alerting	Choose whether to set up alerts. If the synchronization fails or the latency exceeds the specified threshold, DTS sends a notification to the alert contacts. No: No alerts are configured. Yes: Configures alerts. You must also set the alert threshold and alert contact. For more information, see Configure monitoring and alerting during task configuration.

After completing the configuration, click Next: Configure Table And Field at the bottom of the page to set the primary key and distribution columns for the tables to be synchronized to the destination AnalyticDB for PostgreSQL.
Save the task and perform a precheck.
- To view the parameters for configuring this instance via an API operation, hover over the Next: Save Task Settings and Precheck button and click Preview OpenAPI parameters in the tooltip.
- If you have finished viewing the API parameters, click Next: Save Task Settings and Precheck at the bottom of the page.
Note
- Before a synchronization task starts, DTS performs a precheck. You can start the task only if the precheck passes.
- If the precheck fails, click View Details next to the failed item, fix the issue as prompted, and then rerun the precheck.
- If the precheck generates warnings:
  For non-ignorable warning, click View Details next to the item, fix the issue as prompted, and run the precheck again.
  For ignorable warnings, you can bypass them by clicking Confirm Alert Details, then Ignore, and then OK. Finally, click Precheck Again to skip the warning and run the precheck again. Ignoring precheck warnings may lead to data inconsistencies and other business risks. Proceed with caution.
When the Success Rate reaches 100%, click Next: Purchase Instance.

On the Purchase page, select the billing method and link specifications for the data synchronization instance. For more information, see the following table.

Category	Parameter	Description
New Instance Class	Billing Method	Subscription: You pay upfront for a specific duration. This is cost-effective for long-term, continuous tasks. Pay-as-you-go: You are billed hourly for actual usage. This is ideal for short-term or test tasks, as you can release the instance at any time to save costs.
	Resource Group Settings	The resource group to which the instance belongs. The default is default resource group. For more information, see What is Resource Management?.
	Instance Class	DTS offers synchronization specifications at different performance levels that affect the synchronization rate. Select a specification based on your business requirements. For more information, see Data synchronization link specifications.
	Subscription Duration	In subscription mode, select the duration and quantity of the instance. Monthly options range from 1 to 9 months. Yearly options include 1, 2, 3, or 5 years. Note This option appears only when the billing method is Subscription.

Read and select the checkbox for Data Transmission Service (Pay-as-you-go) Service Terms.
Click Buy and Start, and then click OK in the OK dialog box.
You can monitor the task progress on the data synchronization page.