Synchronize Oracle to AnalyticDB for PostgreSQL-Data Transmission Service(DTS)-阿里云帮助中心

Prerequisites

The self-managed Oracle database must be version 9i, 10g, 11g, 12c, 18c, or 19c.
ARCHIVELOG mode is enabled on the self-managed Oracle database, with a reasonable log retention period and accessible archived logs. ARCHIVELOG.
Supplemental logging, supplemental_log_data_pk, and supplemental_log_data_ui are enabled on the self-managed Oracle database. Supplemental Logging.
A destination AnalyticDB for PostgreSQL instance is created. Create an instance.
Before you synchronize data, review the DTS features and limitations for Oracle sources, and use ADAM to evaluate your database for smooth cloud migration. For more information, see Limitations and preparations for Oracle databases and Database evaluation overview.

Limitations

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	Object requirements: Tables must have PRIMARY KEY or UNIQUE constraints with all fields unique. Otherwise, the destination database may contain duplicate data. For Oracle 12c and later, table names cannot exceed 30 bytes. If you select tables as objects and edit them in the destination (such as renaming tables or columns), a single task supports up to 1,000 tables. Exceeding this limit causes a request error. To synchronize more, split tables across multiple tasks or synchronize the entire database. If the source Oracle RAC database connects over Express Connect, specify a VIP when you configure the task. For self-managed Oracle RAC databases, use a VIP instead of a SCAN IP address. Node failover is not supported after you specify the VIP. The redo logging and archive logging features must be enabled. Note For incremental-only synchronization, retain redo logs and archive logs for more than 24 hours. For full + incremental synchronization, retain them for at least seven days. After full synchronization completes, you can set retention to more than 24 hours. Insufficient retention may cause task failures, data inconsistency, or loss, and the DTS SLA may not apply. A primary/secondary switchover on the source database during synchronization causes the task to fail. If the data contains a VARCHAR2 empty string (treated as null by Oracle) and the destination column has a NOT NULL constraint, the task fails. If a table has the Fine-Grained Audit (FGA) policy enabled, DTS cannot detect the `ORA_ROWSCN` pseudocolumn, which causes the task to fail. Note Disable the FGA policy for the table, or exclude the table from synchronization. Do not update LONGTEXT fields during synchronization. Otherwise, the 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	Initial schema synchronization supports the following objects: table, constraint, function, sequence, and view. Warning Schema consistency between source and destination is not guaranteed after initial schema synchronization. Evaluate the impact of data type conversion on your business to avoid task failures or data inconsistency. 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. Delete triggers from the source database to prevent data inconsistency. For more information about how to synchronize triggers, see Configure tasks for source databases with triggers. DTS discards partition definitions for partitioned tables. Define partitions in the destination database. Only tables can be selected as objects. Append-optimized (AO) tables are not supported. If column mapping is used for non-full table synchronization, or if source and destination table structures differ, data for columns missing in the destination is lost. The destination AnalyticDB for PostgreSQL instance does not support the string terminator '\0'. If the data contains this terminator, DTS omits it, which causes data inconsistency. Do not use Oracle Data Pump to write data to the source database during incremental synchronization. Otherwise, data loss may occur. Synchronize data during off-peak hours. During initial full synchronization, DTS consumes read and write resources on both databases, which may increase server load. Concurrent INSERT operations during full synchronization cause table fragmentation. After full synchronization, the destination tablespace is larger than the source. DTS calculates synchronization latency from the timestamp of the latest synchronized data and the current source timestamp. If no DML operations run on the source for a long time, the latency may be inaccurate. Perform a DML operation on the source to refresh the latency. Note If you synchronize an entire database, create a heartbeat table that updates every second. During synchronization, use only DTS to write to the destination database. Writing with other tools (for example, DMS online DDL) may cause data loss or inconsistency. 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.
Cascade synchronization.

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	References
self-managed Oracle database	Fine-grained permissions	Prepare a database account, CREATE USER, and GRANT
AnalyticDB for PostgreSQL instance	Write permissions on the destination database	The initial account of the destination AnalyticDB for PostgreSQL instance has the required permissions. Create a database account. Note You can also use a database account with the RDS_SUPERUSER permission. Manage users and permissions.

Important

Enable archive logging and supplemental logging to capture incremental data. Configure an Oracle database.

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 DMS console layout and style.
- You can also go to the Data Synchronization Tasks page of the new DTS console.
Click Create Task to open the task configuration page.

Configure the source and destination databases.

Category	Setting	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 the connection type for the source database. In this example, Self-managed Database on ECS is selected. Note If the source is a self-managed database, complete the required preparations.
	Instance Region	Select the region of the self-managed Oracle database.
	ECS Instance ID	Select the ID of the ECS instance that hosts the self-managed Oracle database.
	Port	Enter the service port of the self-managed Oracle database. Default: 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 account for the self-managed Oracle database. Permissions required 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 of the destination AnalyticDB for PostgreSQL instance.
	Instance ID	Select the ID of the destination AnalyticDB for PostgreSQL instance.
	Database Name	Enter the name of the destination database in the AnalyticDB for PostgreSQL instance.
	Database Account	Enter the database account for the destination AnalyticDB for PostgreSQL instance. Permissions required for database accounts.
	Database Password	Enter the password for the specified database account.

After the configuration is complete, click Test Connectivity and Proceed at the bottom of the page. In the CIDR Blocks of DTS Servers dialog box, click Test Connectivity.
Note
Ensure that the IP address blocks of the DTS service are added to the security settings of the source and destination databases, either automatically or manually, to allow access from DTS servers. For more information, see Add the IP address whitelist of DTS servers.

Configure the task objects.

On the Configure Objects page, specify the objects to synchronize.

Setting	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 Object 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 Object 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 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 only 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 an object in the Selected Objects section and select the desired operations in the dialog box. To set filter conditions, right-click a table in the Selected Objects section and configure conditions in the dialog box. Set filter conditions. Renaming objects with the object name mapping feature may cause synchronization failures for other objects that depend on the renamed object.

Click Next: Advanced Settings.

Setting	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	Optional. Select an environment tag for the instance.
Actual Write Code	Select the encoding format for data written to the destination.
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.

Click Data Verification to configure a data verification task.
To use the data verification feature, see Configure data verification.
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.

Purchase the instance.

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.