Data Transmission Service (DTS) lets you add or remove synchronization objects from a running data synchronization instance without stopping or reconfiguring it.
Prerequisites
Before you begin, make sure that:
The data synchronization instance is in the Incremental Write phase with a status of Running or Synchronization Failed
The latency of the synchronization instance is less than 10 minutes
The source and destination databases are running normally — don't perform upgrades, configuration changes, network transitions, or cross-zone migrations during the modification, because DTS needs to connect to the databases and read schema information
Limitations
| Limitation | Details |
|---|---|
| Incremental Write module must be running | If it's not running, the modification is blocked. |
| Adding fields syncs only incremental data | When you add fields as synchronization objects, full data for those fields is not synced to the destination. Only incremental data is synced going forward. |
| Synchronization Types changes apply only to newly added objects | Changing Synchronization Types when adding objects does not affect existing objects. |
| Incremental Data Collection module restarts | After adding objects, DTS restarts the Incremental Data Collection module. This may cause a latency of several minutes. |
| Object scope is limited to databases and tables | You can't modify other object types during this process. |
| Data validation tasks can't be modified | Modifying data validation tasks during synchronization object modification is not supported. |
| Whether to Migrate Accounts setting can't be changed | This setting is locked during synchronization object modification. |
| Add and remove must be done in separate steps | To both add and remove objects, first remove and submit, then add. Doing both in one operation may cause an error. |
| DDL operations before table-level modification | Don't perform DDL operations within 5 minutes before modifying table-level synchronization objects — this may cause the sync task to report an error. |
| SQL Server source | You can't add or remove databases during the modification. |
| Two-way synchronization | If no independent conflict resolution policy is configured for the instance, you can't set one during the modification. |
| AnalyticDB for MySQL 2.0 as the destination | Use the previous version of the DTS console. To go to the previous version, move the pointer over the  icon in the lower-right corner of the DMS console and click  . |
Modify synchronization objects
Go to the Data Synchronization page and select the region where the synchronization instance resides.
DTS console
Log on to the DTS console.
In the left-side navigation pane, click Data Synchronization.
DMS console
NoteThe actual operations may vary based on the mode and layout of the DMS console. For more information, see Simple mode and Customize the layout and style of the DMS console.
Log on to the DMS console.
In the top navigation bar, move the pointer over Data + AI and choose .
From the drop-down list to the right of Data Synchronization Tasks, select the region in which the data synchronization instance resides.
In the Actions column of the target synchronization instance, click Reselect Objects.
Modify the synchronization objects:
Add an object: In the Source Objects box, select the object to add, then click
to move it to the Selected Objects box. > Important: > - In the Synchronization Types section, select whether to sync the table schema and full data for the added objects. This selection applies only to the added objects. > - To use the object name mapping feature, first move the objects from Selected Objects back to Source Objects and submit. Then add them back to Selected Objects. The object name mapping feature takes effect after you complete both steps.Remove an object: In the Selected Objects box, select the object to remove, then click
to move it to the Source Objects box.
Click Next: Advanced Settings.
Click Next: Precheck and Start Task.
DTS runs a precheck after each modification. If the precheck fails or reports a warning, resolve the issue and run the precheck again.
When the Success Rate reaches 100%, click Changed. Return.
In the Status column, verify the instance status after the modification.
If Auto Refresh is not enabled, click the
icon above the Actions column to manually refresh the status.
FAQ
Can I modify the Kafka Data Compression Format for a synchronization instance with Kafka as the destination?
Yes.
Can I modify the Message acknowledgement mechanism for a synchronization instance with Kafka as the destination?
Yes.
Can I modify a data validation task when I modify the synchronization objects?
No. Modifying data validation tasks during synchronization object modification is not supported.
The precheck failed after I added a synchronization object. How do I roll back?
Log on to the DTS console.DTS consoleDMS console
In the task list, find the target task and click the task ID.
In the left-side navigation pane, click Synchronization Object Modification Records
How do I perform a full resynchronization for a specific object?
Remove the object first, then add it back:
In the Actions column, click Reselect Objects. In the Selected Objects box, select the object to remove, then click
to move it to the Source Objects box. Click Next: Advanced Settings and Next: Precheck and Start Task. When the success rate is 100%, click Changed. Return.Before adding the object back, delete it from the destination database to prevent data inconsistency.
In the Actions column, click Reselect Objects again. In the Source Objects box, select the object, then click
to move it to the Selected Objects box. Click Next: Advanced Settings and Next: Precheck and Start Task. When the success rate is 100%, click Changed. Return.