Data Transmission Service:Resolve table errors in a data synchronization instance

Prerequisites

• No applications are reading from the destination database, or your applications can tolerate a brief interruption.
• The source database and destination database are running properly.
• The data synchronization instance has other objects to synchronize besides the table with the error.
• The Status of the instance cannot be Modifying Objects.

Considerations

• Reselecting synchronization objects automatically restarts the instance. During the restart, data may be temporarily inconsistent between the source and destination databases.
• You must clear the data in the destination table. Before you proceed, ensure that:

  • Only DTS is writing data to the destination table, or the data in the table can be cleared.
  • Services that depend on the destination table are not affected.

Process

1. Remove the table with errors or hot data from the data synchronization instance.
2. Clear the data from the table with errors in the destination database.
3. Add the table with errors back to the data synchronization instance.

Procedure

1. Go to the Data Synchronization Tasks page.

   1. Log on to the Data Management (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.

2. Based on your scenario, remove the table with errors or hot data.
   Note For more information about how to view hot data, see View hot data information.

   • If the synchronization object is at the database level:
     1. Find the target data synchronization instance in the task list and click Operation in the Reselect Objects column.
     2. In the Selected Objects panel, select the database that contains the table with errors, and click the icon to remove it.
     3. In the Source Objects panel, select the objects to synchronize at the table level (excluding the table with errors), and click the icon to add them to the Selected Objects panel.
        Note For more information, see Remove a synchronization object.
     4. Click Next: Advanced Settings and then click Next: Precheck and Start Task.
     5. When the precheck Success Rate is 100%, click Changed. Return .
   • If the synchronization object is at the table level:
     1. Find the target data synchronization instance in the task list and click Operation in the Reselect Objects column.
     2. In the Selected Objects panel, select the table with errors, and click the icon to remove it.
     3. Click Next: Advanced Settings and then click Next: Precheck and Start Task.
     4. When the precheck Success Rate is 100%, click Changed. Return .
3. Clear the data from the table with errors in the destination database.
   For example, to clear data from a table in a MySQL database, you can run the following commands:

   TRUNCATE TABLE XXX;
   DROP TABLE XXX;

4. Add the table back as a synchronization object.
   1. Find the target data synchronization instance in the task list and click Operation in the Reselect Objects column.
      
   2. In the Source Objects panel, select the table, and click the icon to add it to the Selected Objects panel.
      Note For more information, see Add a synchronization object.
   3. Click Next: Advanced Settings and then click Next: Precheck and Start Task.
      
   4. When the precheck Success Rate is 100%, click Changed. Return .
      
5. After the instance automatically restarts, verify that the error is resolved.