Configure trigger synchronization or migration

Prerequisites

• The source and destination databases must be of a supported type, such as from an ApsaraDB RDS for MariaDB instance to an ApsaraDB RDS for MySQL instance. For more information, see Supported instances.

• The instance is configured for both schema and incremental tasks.

  • Migration instance: For Migration Types, you must select Schema Migration and Incremental Data Migration.

  • Synchronization instance: For Synchronization Types, Incremental Data Synchronization is selected by default, and you must also select Schema Synchronization.

• When you configure the instance, you must select objects for Source Objects at the entire database or schema level.

Supported instances

Instance configuration

In the Configure Objects step, select an option for Method to Migrate Triggers in Source Database.

• Select Manual Migration: During schema migration, DTS generates an object ignored due to incremental migration is enabled alert for any trigger it encounters and does not migrate it to the destination database. You must manually synchronize or migrate the triggers from the source database to the destination database before you end the incremental task. For more information, see Manual migration.

• Select Automatically Migrate: No additional actions are required.

Manual migration

1. Go to the data synchronization task list page in the destination region. You can do this in one of two ways.

   DTS console

   1. Log on to the DTS console.

   2. In the navigation pane on the left, click Data Synchronization.

   3. In the upper-left corner of the page, select the region where the synchronization instance is located.

   DMS console

   Note

   The actual steps may vary depending 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.

   1. Log on to the DMS console.

   2. In the top menu bar, choose Data + AI > DTS (DTS) > Data Synchronization.

   3. To the right of Data Synchronization Tasks, select the region of the synchronization instance.

2. Click the ID of the target instance.

3. Optional: In the left-side navigation pane, click Task Management.

4. In the Progress section, click the Incremental Write module.

5. On the Basic Information tab, click Migrate Triggers.

   Note

   If the Migrate Triggers button is not displayed, no triggers were found during the schema migration.

   You can view the trigger synchronization results in the Progress section, within the Schema Migration3 module.

Automatic migration

DTS copies the trigger code from the source database, adds a control statement to the trigger's header, and then writes the modified code to the destination database. The following code shows an example:

CREATE TRIGGER testref BEFORE INSERT ON test1
  FOR EACH ROW
  BEGIN
    INSERT INTO test2 SET a2 = NEW.a1;
  END;

CREATE TRIGGER testref BEFORE INSERT ON test1
  FOR EACH ROW
  BEGIN
    IF (SELECT @`__#aliyun_dts_writer#__) IS NULL THEN
        INSERT INTO test2 SET a2 = NEW.a1;
    END IF;
  END;

FAQ

• What is meant by a task that includes both schema and incremental operations?

  For a synchronization instance, this means both Schema Synchronization and Incremental Data Synchronization are selected under Synchronization Types. For a migration instance, this means both Schema Migration and Incremental Data Migration are selected under Migration Types.

• How do I end an incremental task?

  You can end an incremental task by terminating, resetting, or releasing the instance. For more information, see Terminate a DTS instance, Reset a DTS instance, and Release a DTS instance.