Data Transmission Service:Synchronize data from a self-managed TiDB database to an AnalyticDB for MySQL V3.0 cluster

Prerequisites

• The destination AnalyticDB for MySQL V3.0 cluster is created. The available storage space of this cluster is larger than the total size of data in the source TiDB database. For more information, see Create a cluster.

• By default, the data synchronization task involves incremental data synchronization. Preparations are made to collect incremental data if you want to synchronize incremental data from the TiDB database. For more information, see the Preparations section of this topic.

Preparations

You can use one of the following methods to collect incremental data from the TiDB database:

Usage notes

Billing

SQL operations that support incremental synchronization

Permissions required for database accounts

Procedure

1. Go to the Data Synchronization Tasks page.

   1. Log on to the DMS console.

   2. In the top navigation bar, move the pointer over DTS.

   3. Choose DTS (DTS) > Data Synchronization.

   Note

   • The actual operation may vary depending on the mode and layout of DMS. For more information, see Simple mode and Customize the layout and style of the DMS console.

   • You can also go to the Data Synchronization Tasks page of the new DTS console.

2. On the right side of Data Synchronization Tasks, select the region in which you want to create the data synchronization task.

   Note

   If you use the new DTS console, select the region in which you want to create the data synchronization task in the top navigation bar.

3. Click Create Task to go to the task configuration page.

4. Optional: In the upper-right corner of the page, click New Configuration Page.

   Note

   • Skip this step if the Back to Previous Version button is displayed in the upper-right corner of the page.

   • Some parameters may differ between the new and previous versions of the configuration page. We recommend that you use the new configuration page.

5. Configure the source and destination databases. The following table describes the parameters.

   Section	Parameter	Description
   N/A	Task Name	The name of the task. DTS automatically assigns a name to the task. We recommend that you specify a descriptive name that makes it easy to identify the task. You do not need to specify a unique task name.
   Source Database	Select a DMS database instance.	The database instance that you want to use. You can choose whether to use an existing instance based on your business requirements. If you select an existing instance, DTS automatically populates the parameters for the database. If you do not select an existing instance, you must configure parameters for the source database. Note In the DMS console, you can click Create Template to register a database with DMS. For more information, see Register an Alibaba Cloud database instance and Register a database hosted on a third-party cloud service or a self-managed database. In the DTS console, register a database with DTS on the Database Connections page or the new configuration page. For more information, see Manage database connections.
   	Database Type	The type of the source database. Select TiDB.
   	Access Method	The access method of the source database. Select an access method based on the deployment location of the TiDB database. In this example, select Self-managed Database on ECS. Note If you set this parameter to other values, you must prepare the environment that is required for the self-managed database before data synchronization. For more information, see Preparation overview.
   	Instance Region	The region in which the TiDB database resides.
   	ECS Instance ID	The ID of the ECS instance that hosts the TiDB database. Default value: 4000.
   	Port Number	The service port number of the TiDB database.
   	Database Account	The account of the TiDB database. For more information about the permissions that are required for the account, see the Permissions required for database accounts section of this topic.
   	Database Password	The password of the database account.
   	Migrate Incremental Data	This parameter is set to Yes by default. You cannot change the value of this parameter. Note If you do not want to synchronize incremental data from the TiDB database, create a data migration task. For more information, see Migrate data from a self-managed TiDB database to an AnalyticDB for MySQL V3.0 cluster.
   	Kafka Cluster Type	The type of the Kafka cluster. Configure this parameter based on the deployment location of the Kafka cluster. In this example, select Self-managed Database on ECS. Note If you select Express Connect, VPN Gateway, or Smart Access Gateway, you must also select a VPC from the Connected VPC drop-down list and specify IP Address or Domain Name.
   	Kafka Data Source Component	Select Use the default binlog format of the TiDB database. or Use the TiCDC Canal-JSON format. based on the preparations you made.
   	ECS Instance ID	The ID of the ECS instance to which the Kafka cluster belongs.
   	Port Number	The service port of the Kafka cluster.
   	Kafka Cluster Account	The username and password of the Kafka cluster. If authentication is not enabled for the Kafka cluster, you do not need to configure this parameter.
   	Kafka Cluster Password
   	Kafka Version	The Kafka cluster version. Note If the Kafka cluster version is 1.0 or later, select 1.0.
   	Encryption	Specifies whether to encrypt the connection to the Kafka cluster. Select Non-encrypted or SCRAM-SHA-256 based on your business and security requirements.
   	Topic	The topic to which the incremental data belongs.
   Destination Database	Select a DMS database instance.	The database instance that you want to use. You can choose whether to use an existing instance based on your business requirements. If you select an existing instance, DTS automatically populates the parameters for the database. If you do not select an existing instance, you must configure parameters for the source database. Note In the DMS console, you can click Create Template to register a database with DMS. For more information, see Register an Alibaba Cloud database instance and Register a database hosted on a third-party cloud service or a self-managed database. In the DTS console, register a database with DTS on the Database Connections page or the new configuration page. For more information, see Manage database connections.
   	Database Type	The type of the destination database. Select AnalyticDB for MySQL 3.0.
   	Access Method	The access method of the destination database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the destination AnalyticDB for MySQL V3.0 cluster resides.
   	Instance ID	The ID of the destination AnalyticDB for MySQL V3.0 cluster.
   	Database Account	The database account of the destination AnalyticDB for MySQL V3.0 cluster. For more information about the permissions that are required for the account, see the Permission requirements for database accounts section of this topic.
   	Database Password	The password of the database account.

6. In the lower part of the page, click Test Connectivity and Proceed.

   If the source or destination database is an Alibaba Cloud database instance, such as an ApsaraDB RDS for MySQL or ApsaraDB for MongoDB instance, DTS automatically adds the CIDR blocks of DTS servers to the whitelist of the instance. If the source or destination database is a self-managed database hosted on an Elastic Compute Service (ECS) instance, DTS automatically adds the CIDR blocks of DTS servers to the security group rules of the ECS instance, and you must make sure that the ECS instance can access the database. If the database is deployed on multiple ECS instances, you must manually add the CIDR blocks of DTS servers to the security group rules of each ECS instance. If the source or destination database is a self-managed database that is deployed in a data center or provided by a third-party cloud service provider, you must manually add the CIDR blocks of DTS servers to the whitelist of the database to allow DTS to access the database. For more information, see Add the CIDR blocks of DTS servers.

   Warning

   If the CIDR blocks of DTS servers are automatically or manually added to the whitelist of the database or instance, or to the ECS security group rules, security risks may arise. Therefore, before you use DTS to synchronize data, you must understand and acknowledge the potential risks and take preventive measures, including but not limited to the following measures: enhancing the security of your username and password, limiting the ports that are exposed, authenticating API calls, regularly checking the whitelist or ECS security group rules and forbidding unauthorized CIDR blocks, or connecting the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

7. Configure the objects to be synchronized.

   1. On the Select Objects page, configure the objects that you want to synchronize.

      Parameter	Description
      Synchronization Types	By default, Incremental Data Synchronization is selected. You must also select Schema Synchronization and Full Data Synchronization. After the precheck is complete, DTS synchronizes the historical data of the selected objects from the source database to the destination cluster. The historical data is the basis for subsequent incremental synchronization.
      Processing Mode of Conflicting Tables	Precheck and Report Errors: checks whether the destination database contains tables that have the same names as tables in the source database. If the source and destination databases do not contain tables that have identical table names, the precheck is passed. Otherwise, an error is returned during the precheck, and the data synchronization task cannot be started. Note If the source and destination databases contain tables with identical names and the tables in the destination database cannot be deleted or renamed, you can use the object name mapping feature to rename the tables that are synchronized to the destination database. For more information, see Map object names. Ignore Errors and Proceed: skips the precheck for identical table names in the source and destination databases. Warning If you select Ignore Errors and Proceed, data inconsistency may occur and your business may be exposed to potential risks. If the source and destination databases have the same schema and a data record in the destination database has the same primary key value or unique key value as a data record in the source database: During full data synchronization, DTS does not synchronize the data record to the destination database. The existing data record in the destination database is retained. During incremental data synchronization, DTS synchronizes the data record to the destination database. The existing data record in the destination database is overwritten. If the source and destination databases have different schemas, data may fail to be initialized. In this case, only some columns are synchronized, or the data synchronization task fails. Proceed with caution.
      Capitalization of Object Names in Destination Instance	The capitalization of database names, table names, and column names in the destination instance. By default, DTS default policy is selected. You can select other options to ensure that the capitalization of object names is consistent with that in the source or destination database. For more information, see Specify the capitalization of object names in the destination instance.
      Source Objects	Select one or more objects from the Source Objects section and click the icon to move the objects to the Selected Objects section. Note You can select databases or tables as the objects to be synchronized.
      Selected Objects	To rename an object that you want to synchronize to the destination instance, right-click the object in the Selected Objects section. For more information, see the Map the name of a single object section of the Map object names topic. To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see the Map multiple object names at a time section of the Map object names topic. Note To specify WHERE conditions to filter data, right-click a table in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information, see Set filter conditions. If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be synchronized.

   2. Click Next: Advanced Settings to configure advanced settings.

      Parameter	Description
      Retry Time for Failed Connections	The retry time range for failed connections. If the source or destination database fails to be connected after the data synchronization task is started, DTS immediately retries a connection within the time range. Valid values: 10 to 1440. Unit: minutes. Default value: 720. We recommend that you set this parameter to a value greater than 30. If DTS reconnects to the source and destination databases within the specified time range, DTS resumes the data synchronization task. Otherwise, the data synchronization task fails. Note If you specify different retry time ranges for multiple data synchronization tasks that have the same source or destination database, the shortest retry time range takes precedence. When DTS retries a connection, you are charged for the DTS instance. We recommend that you specify the retry time range based on your business requirements. You can also release the DTS instance at your earliest opportunity after the source and destination instances are released.
      Retry Time for Other Issues	The retry time range for other issues. For example, if the DDL or DML operations fail to be performed after the data synchronization task is started, DTS immediately retries the operations within the time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set this parameter to a value greater than 10. If the failed operations are successfully performed within the specified time range, DTS resumes the data synchronization task. Otherwise, the data synchronization task fails. Important The value of the Retry Time for Other Issues parameter must be smaller than the value of the Retry Time for Failed Connections parameter.
      Enable Throttling for Full Data Migration	During full data synchronization, DTS uses the read and write resources of the source and destination databases. This may increase the load on the database servers. You can configure the Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) parameters for full data synchronization tasks to reduce the load on the destination database server. Note This parameter is displayed only if Full Data Synchronization is selected for the Synchronization Types parameter.
      Enable Throttling for Incremental Data Synchronization	Specifies whether to enable throttling for incremental data synchronization. You can enable throttling for incremental data synchronization based on your business requirements. To configure throttling, you must configure the RPS of Incremental Data Synchronization and Data synchronization speed for incremental synchronization (MB/s) parameters. This reduces the load on the destination database server.
      Environment Tag	The environment tag that is used to identify the DTS instance. You can select an environment tag based on your business requirements. In this example, you do not need to configure this parameter.
      Configure ETL	Specifies whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values: Yes: configures the ETL feature. You can enter data processing statements in the code editor. For more information, see Configure ETL in a data migration or data synchronization task. No: does not configure the ETL feature.
      Monitoring and Alerting	Specifies whether to configure alerting for the data synchronization task. If the task fails or the synchronization latency exceeds the specified threshold, alert contacts will receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see Configure monitoring and alerting when you create a DTS task.

   3. Click Next: Verification Configurations to configure data verification.

      For more information about how to use the data verification feature, see Configure data verification.

   4. Optional. Click Next: Configure Database and Table Fields. On the page that appears, configure Type, Primary Key Column, and Distribution Key for the tables that you want to synchronize to the destination AnalyticDB for MySQL V3.0 cluster.

      Note

      • This step is available only if you select Schema Migration for Migration Types. You can set Definition Status to All and then modify the database and table fields.

      • In the Primary Key Column field, you can specify multiple columns to form a composite primary key. In this case, you must specify one or more Primary Key Column as the Distribution Key. For more information, see CREATE TABLE.

8. Save the task settings and run a precheck.

   • To view the parameters to be specified when you call the relevant API operation to configure the DTS task, move the pointer over Next: Save Task Settings and Precheck and click Preview OpenAPI parameters.

   • If you do not need to view or have viewed the parameters, click Next: Save Task Settings and Precheck in the lower part of the page.

   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 View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, run a precheck again.

   • If an alert is generated for an item during the precheck, perform the following operations based on the scenario:

     • If an alert item cannot be ignored, click View Details next to the failed item and troubleshoot the issue. Then, run a precheck again.

     • If an alert item can be ignored, click Confirm Alert Details. In the View Details dialog box, click Ignore. In the message that appears, click OK. Then, click Precheck Again to run a precheck again. If you ignore the alert item, data inconsistency may occur and your business may be exposed to potential risks.

9. Wait until the success rate becomes 100%. Then, click Next: Purchase Instance.

10. Purchase a data synchronization instance.

    1. On the Purchase Instance page, configure the Billing Method and Instance Class parameters for the data synchronization instance. The following table describes the parameters.

       Section	Parameter	Description
       New Instance Class	Billing Method	Subscription: You pay for your subscription when you create an instance. The subscription billing method is more cost-effective than the pay-as-you-go billing method for long-term use. You are offered lower prices for longer subscription durations. Pay-as-you-go: A pay-as-you-go instance is billed on an hourly basis. The pay-as-you-go billing method is suitable for short-term use. If you no longer require a pay-as-you-go instance, you can release the instance to reduce costs.
       	Resource Group Settings	The resource group to which the instance belongs. Default value: default resource group. For more information, see What is Resource Management?
       	Instance Class	DTS provides various synchronization specifications that support different performance. The synchronization speed varies based on the synchronization specifications that you select. You can select a synchronization specification based on your business requirements. For more information, see Instance classes of data synchronization instances.
       	Subscription Duration	If you select the subscription billing method, set the subscription duration and the number of instances that you want to create. The subscription duration can be one to nine months, one year, two years, three years, or five years. Note This parameter is available only if you select the Subscription billing method.

    2. Read and select the Data Transmission Service (Pay-as-you-go) Service Terms.

    3. Click Buy and Start to start the data synchronization task. You can view the progress of the task in the task list.