Data Transmission Service:Synchronize data from a PolarDB for MySQL cluster to a self-managed Kafka cluster

Precautions

The source database must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.

Limits

• You can select only tables as the objects to be synchronized.
• DTS does not automatically update the objects of the data synchronization task based on their names.
  Note If a source table is renamed during data synchronization but the new table name is not included in the selected objects, DTS does not synchronize the data of the table to the destination Kafka cluster. To synchronize the data of the renamed table, you must add the table to the selected objects of the task. For more information, see Add an object to a data synchronization task.

Procedure

1. Purchase a data synchronization instance. For more information, see Purchase a DTS instance.
   Note On the buy page, set Source Instance to PolarDB, set Target Instance to Kafka, and set Synchronization Topology to One-Way Synchronization.
2. Log on to the DTS console.
   Note If you are redirected to the Data Management (DMS) console, you can click the icon in the lower-right corner to go to the previous version of the DTS console.
3. In the left-side navigation pane, click Data Synchronization.
4. In the upper part of the Data Synchronization Tasks page, select the region in which the destination instance resides.
5. Find the data synchronization instance and click Configure Task in the Actions column.
6. Configure the source and destination instances.
   

   Section	Parameter	Description
   N/A	Synchronization Task Name	DTS automatically generates a task name. We recommend that you specify an informative name for easy identification. You do not need to use a unique task name.
   Source Instance Details	Instance Type	This parameter is set to PolarDB Instance and cannot be changed.
   	Instance Region	The source region that you selected on the buy page. You cannot change the value of this parameter.
   	PolarDB Instance ID	Select the ID of the PolarDB for MySQL cluster.
   	Database Account	Enter the database account of the PolarDB for MySQL cluster. The account must have the read permissions on the objects to be synchronized.
   	Database Password	Enter the password of the database account.
   Destination Instance Details	Instance Type	Select an instance type based on the deployment of the Kafka cluster. In this example, select User-Created Database in ECS Instance. Note If you select other instance types, you must deploy the network environment for the Kafka cluster. For more information, see Preparation overview.
   	Instance Region	The destination region that you selected on the buy page. You cannot change the value of this parameter.
   	ECS Instance ID	Select the ID of the Elastic Compute Service (ECS) instance on which the Kafka cluster is deployed.
   	Database Type	Select Kafka.
   	Port Number	Enter the service port number of the Kafka cluster. The default port number is 9092.
   	Database Account	Enter the username that is used to log on to the Kafka cluster. If no authentication is enabled for the Kafka cluster, you do not need to enter the username.
   	Database Password	Enter the password that corresponds to the username. If no authentication is enabled for the Kafka cluster, you do not need to enter the password.
   	Topic	Click Get Topic List, and select a topic name from the drop-down list.
   	Kafka Version	Select the version of the destination Kafka cluster.
   	Encryption	Select Non-encrypted or SCRAM-SHA-256 based on your business and security requirements.

7. In the lower-right corner of the page, click Set Whitelist and Next.
   Note DTS adds the CIDR blocks of DTS servers to the whitelist of the source PolarDB cluster and the inbound rule of the destination ECS instance. This ensures that DTS servers can connect to the source cluster and the destination instance.
8. Select the objects to be synchronized.
   

   Parameter	Description
   Data Format in Kafka	The data that is synchronized to the Kafka cluster is stored in the Avro or Canal JSON format. For more information, see Data formats of a Kafka cluster.
   Policy for Shipping Data to Kafka Partitions	The policy used to synchronize data to Kafka partitions. Select a policy based on your business requirements. For more information, see Specify the policy for synchronizing data to Kafka partitions.
   Objects to be synchronized	Select one or more tables from the Available section and click the icon to add the tables to the Selected section. Note DTS maps the table names to the topic name that you select in Step 6. You can use the table name mapping feature to change the topics that are synchronized to the destination cluster. For more information, see Rename an object to be synchronized.
   Rename Databases and Tables	You can use the object name mapping feature to rename the objects that are synchronized to the destination instance. For more information, see Object name mapping.
   Retry Time for Failed Connections	By default, if DTS fails to connect to the source or destination database, DTS retries within the next 720 minutes (12 hours). You can specify the retry time based on your needs. If DTS reconnects to the source and destination databases within the specified time, DTS resumes the data synchronization task. Otherwise, the data synchronization task fails. Note When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time based on your business needs. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.

9. In the lower-right corner of the page, click Next.
10. Configure initial synchronization.
    

    Parameter	Description
    Initial Synchronization	Select both Initial Schema Synchronization and Initial Full Data Synchronization. DTS synchronizes the schemas and historical data of the required objects and then synchronizes incremental data.
    Filter options	Ignore DDL in incremental synchronization phase is selected by default. In this case, DTS does not synchronize DDL operations that are performed on the source database during incremental data synchronization.

11. In the lower-right corner of the page, click Precheck.
    Note

    • Before you can start the data synchronization task, DTS performs a precheck. You can start the data synchronization task only after the task passes the precheck.
    • If the task fails to pass the precheck, click the icon next to each failed item to view details.
      • After you troubleshoot the issues based on the causes, run a precheck again.
      • If you do not need to troubleshoot the issues, ignore failed items and run a precheck again.
12. Close the Precheck dialog box after the following message is displayed: Precheck Passed. Then, the data synchronization task starts.
    You can view the status of the data synchronization task on the Data Synchronization page.