What do I do if an alert is reported for the check item Check the existence of objects in the destination database?-Data Transmission Service(DTS)-阿里云帮助中心

During the Precheck step of a Data Transmission Service (DTS) data synchronization or migration task, the Check the existence of objects in the destination database. check item may be marked as Warning. This alert is triggered when two conditions are both true: the destination database or table already contains data (for example, the database used to receive data in the destination ApsaraDB for Redis instance has existing data), and the Processing Mode of Conflicting Tables parameter in the Configure Objects and Advanced Settings step is set to Precheck and Report Errors.

Resolve the alert

In the Precheck step, find the Check the existence of objects in the destination database. check item and click Confirm Alert Details.
In the View Details message, view the cause of failure in the Check Result section.
Based on the description of the Cause parameter, check the data in the destination instance.
Decide whether to keep the existing data in the destination database, then follow the steps for your situation:
- To keep the existing data, choose one of the following options:
  - Remap the source object: Go back to the Configure Objects and Advanced Settings step and use the object name mapping feature to redirect the source object to a different database or table in the destination instance. For more information, see Map object names.
  - Exclude the source object from the task: Go back to the Configure Objects and Advanced Settings step and remove the source object from the Selected Objects section.
- To discard the existing data, choose one of the following options:
  - Delete the existing data: Manually delete the data from the destination database. Then click Close in the View Details message and click Precheck Again.
  - Ignore the alert: In the View Details message, click Ignore, then click OK in the confirmation message. Then, in the lower part of the Precheck step, click Precheck Again.
Perform subsequent steps as prompted.