Data Transmission Service:Synchronize data from a self-managed MySQL database to a Message Queue for Apache Kafka instance

Precautions

• DTS uses read and write resources of the source and destination databases during initial full data synchronization. This may increase the loads of the database servers. If the database performance is unfavorable, the specification is low, or the data volume is large, database services may become unavailable. For example, DTS occupies a large amount of read and write resources in the following cases: a large number of slow SQL queries are performed on the source database, the tables have no primary keys, or a deadlock occurs in the destination database. Before you synchronize data, evaluate the impact of data synchronization on the performance of the source and destination databases. We recommend that you synchronize data during off-peak hours. For example, you can synchronize data when the CPU utilization of the source and destination databases is less than 30%.
• 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

• Only tables can be selected as the objects to synchronize.
• DTS does not synchronize the data in a renamed table to the destination Kafka cluster. This applies if the new table name is not included in the objects to synchronize. If you want to synchronize the data in a renamed table to the destination Kafka cluster, you must reselect the objects to be synchronized. For more information, see Add an object to a data synchronization task.

Before you begin

Procedure

1. Purchase a data synchronization instance. For more information, see Purchase a DTS instance.
   Note On the buy page, set Source Instance to MySQL, set Dstination Instance to Kafka, and set Synchronization Topology to One-way Synchronization.
2. Log on to the DTS console.
3. In the left-side navigation pane, click Data Synchronization.
4. At the top of the Synchronization Tasks page, select the region where the destination instance resides.
5. Find the data synchronization instance and click Configure Synchronization Channel in the Actions column.
6. Configure the source and destination instances.
   

   Section	Parameter	Description
   None	Synchronization Task Name	DTS automatically generates a task name. We recommend that you specify an informative name to identify the task. You do not need to use a unique task name.
   Source Instance Details	Instance Type	Select an instance type based on the deployment of the source database. In this example, select User-Created Database in ECS Instance. You can also follow the procedure to configure data synchronization tasks for other types of self-managed MySQL databases.
   	Instance Region	The source 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 that hosts the self-managed MySQL database.
   	Database Type	This parameter is set to MySQL and cannot be changed.
   	Port Number	Enter the service port number of the self-managed MySQL database.
   	Database Account	Enter the account of the self-managed MySQL database. The account must have the SELECT permission on the required objects, the REPLICATION CLIENT permission, the REPLICATION SLAVE permission, and the SHOW VIEW permission.
   	Database Password	Enter the password of the database account.
   Destination Instance Details	Instance Type	Select User-Created Database Connected over Express Connect, VPN Gateway, or Smart Access Gateway. Note You cannot select Message Queue for Apache Kafka as the instance type. You can use Message Queue for Apache Kafka as a self-managed Kafka database to configure data synchronization.
   	Instance Region	The destination region that you selected on the buy page. You cannot change the value of this parameter.
   	Peer VPC	Select the ID of the virtual private cloud (VPC) to which the destination Message Queue for Apache Kafka instance belongs. To obtain the VPC ID, you can log on to the Message Queue for Apache Kafka console and go to the Instance Details page of the Message Queue for Apache Kafka instance. In the Basic Information section, you can view the VPC ID.
   	Database Type	Select Kafka.
   	IP Address	Enter an IP address that is included in the Default Endpoint parameter of the Message Queue for Apache Kafka instance. Note To obtain an IP address, you can log on to the Message Queue for Apache Kafka console and go to the Instance Details page of the Message Queue for Apache Kafka instance. In the Basic Information section, you can obtain an IP address from the Default Endpoint parameter.
   	Port Number	Enter the service port number of the Message Queue for Apache Kafka instance. The default port number is 9092.
   	Database Account	Enter the username that is used to log on to the Message Queue for Apache Kafka instance. Note If the instance type of the Message Queue for Apache Kafka instance is VPC Instance, you do not need to specify the database account or database password.
   	Database Password	Enter the password of the username.
   	Topic	Click Get Topic List and select a topic name from the drop-down list.
   	Kafka Version	Select the version of the Message Queue for Apache Kafka instance.
   	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

   • You do not need to modify the security settings for ApsaraDB instances (such as ApsaraDB RDS for MySQL and ApsaraDB for MongoDB) and ECS-hosted databases. DTS automatically adds the CIDR blocks of DTS servers to the whitelists of ApsaraDB instances or the security group rules of Elastic Compute Service (ECS) instances. For more information, see Add the CIDR blocks of DTS servers to the security settings of on-premises databases.
   • After data synchronization is complete, we recommend that you remove the CIDR blocks of DTS servers from the whitelists or security groups.
8. Select the objects to synchronize.
   

   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.
   Select the objects to synchronize	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. If you want to rename the topic, you can use the object name mapping feature. 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.
    

    Setting	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, you can click the icon next to each failed item to view details.
      • You can troubleshoot the issues based on the causes and run a precheck again.
      • If you do not need to troubleshoot the issues, you can 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 state of the data synchronization task on the Synchronization Tasks page.