Tablestore:Synchronize data from PolarDB-X 2.0 to Tablestore

Prerequisites

• A Tablestore instance is created. For more information, see Create a Tablestore instance.

• The AccessKey ID and AccessKey secret of the Alibaba Cloud account to which the Tablestore instance belongs are obtained. For more information, see Create an AccessKey pair.

Usage notes

SQL operations that can be incrementally synchronized

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 Development.

   3. In the left-side navigation pane, choose DTS (DTS) > Data Synchronization.

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

   Note

   • The actual steps that you need to perform may vary based on the mode and layout of the DMS console. 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. Click Create Task to go to the task configuration page.

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

      Note

      • If the Back to Previous Version button is displayed in the upper-right corner of the page, skip this step.

      • Specific parameters in the new and previous versions of the configuration page may be different. We recommend that you use the new version of the configuration page.

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

      Section	Parameter	Description
      N/A	Task Name	The name of the DTS task. DTS automatically generates a task name. 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 an existing DMS database instance. (Optional. If you have not registered a DMS database instance, ignore this option and configure database settings in the section below.)	The database that you want to use. You can choose whether to use an existing database based on your business requirements. If you select an existing database, DTS automatically populates the parameters for the database. If you do not select an existing database, you must configure the following database information.
      	Database Type	The type of the source database. Select PolarDB-X 2.0.
      	Access Method	The access method of the source database. Select Alibaba Cloud Instance.
      	Instance Region	The region in which the PolarDB-X 2.0 instance resides.
      	Replicate Data Across Alibaba Cloud Accounts	Specifies whether to synchronize data across Alibaba Cloud accounts. In this example, No is selected. For information about data synchronization across Alibaba Cloud accounts, see Configure a DTS task across Alibaba Cloud accounts.
      	Instance ID	The ID of the source PolarDB-X 2.0 instance.
      	Database Account	The database account of the source PolarDB-X 2.0 instance. The database account must have the permissions to perform the SELECT, REPLICATION SLAVE, and REPLICATION CLIENT operations on the objects that you want to synchronize. Note For information about how to grant the required permissions to a database account, see Manage database accounts and Permissions required for an account to synchronize data.
      	Database Password	The password that is used to access the database.
      Destination Database	Select an existing DMS database instance. (Optional. If you have not registered a DMS database instance, ignore this option and configure database settings in the section below.)	The database that you want to use. You can choose whether to use an existing database based on your business requirements. If you select an existing database, DTS automatically populates the parameters for the database. If you do not select an existing database, you must configure the following database information.
      	Database Type	The type of the destination database. Select Tablestore.
      	Access Method	The access method of the destination database. Select Alibaba Cloud Instance.
      	Instance Region	The region in which the destination Tablestore instance resides.
      	Instance ID	The ID of the destination Tablestore instance.
      	AccessKey ID of Alibaba Cloud Account	The AccessKey ID of the Alibaba Cloud account to which the destination Tablestore instance belongs. Important If you enter the AccessKey ID of a RAM user, you must attach the AliyunOTSFullAccess policy to the RAM user. The AliyunOTSFullAccess policy grants the RAM user the permissions to manage Tablestore. For more information, see Use a RAM policy to grant permissions to a RAM user.
      	AccessKey Secret of Alibaba Cloud Account	The AccessKey secret of the Alibaba Cloud account to which the destination Tablestore instance belongs.

   3. 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 the "CIDR blocks of DTS servers" section of the Add the CIDR blocks of DTS servers topic.

      Warning

      If the public CIDR blocks of DTS servers are automatically or manually added to the whitelist of a database instance or to the security group rules of an ECS instance, 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 security group rules and prohibiting unauthorized CIDR blocks, or connecting the database instance to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

3. Configure the objects that you want to synchronize in the data synchronization task.

   1. On the Configure Objects page, configure the objects that you want to synchronize. The following table describes the parameters.

      Parameter	Description
      Synchronization Types	The 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.
      Operation Types	The types of operations that you want to synchronize. Select the operation types that you want to synchronize based on your business requirements. By default, all operation types are selected.
      Processing Policy of Dirty Data	The processing policy for handling data write errors. Valid values: Skip Block
      Data Write Mode	The mode in which data is written. Valid values: Overwrite Row: The UpdateRowChange operation is performed to overwrite rows in the Tablestore instance. Update Row: The PutRowChange operation is performed to update rows in the Tablestore instance.
      Batch Write Mode	The operation used to write multiple rows of data to the Tablestore instance at the same time. Valid values: BulkImportRequest: Data is written offline. BatchWriteRowRequest: Multiple rows of data are written at the same time. Note To achieve higher read and write efficiency and reduce the costs of using the Tablestore instance, we recommend that you select BulkImportRequest.
      More	You can click More to configure the following parameters based on your business requirements: Queue Size: the length of the queue for writing data to the Tablestore instance. Thread Quantity: the number of callback threads for writing data to the Tablestore instance. Concurrency: the maximum number of concurrent threads for the Tablestore instance. Buckets: the number of buckets in which incremental data can be concurrently written in sequence. To improve the concurrent write capability, you can set this parameter to a large value. Note The value of the Buckets parameter must be less than or equal to the value of the Concurrency parameter.
      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 add the objects to the Selected Objects section. Note You can select tables or databases as the objects that you want to synchronize. If you select tables as the objects that you want to synchronize, DTS does not synchronize other objects, such as views, triggers, and stored procedures, to the destination database. You can select only one database or multiple tables in the same database as the objects that you want to synchronize.
      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 The database name mapping feature is not supported. You can use the object name mapping feature to rename tables and columns only if you select tables as the objects that you want to synchronize. If you use the object name mapping feature to rename an object, other objects that depend on the object may fail to be synchronized. You can use the column name mapping feature to modify the data types of the corresponding columns in the destination Tablestore instance. 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 Specify filter conditions.

   2. Click Next: Advanced Settings to configure advanced settings. The following table describes the parameters.

      Parameter	Description
      Dedicated Cluster for Task Scheduling	By default, DTS schedules the task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data synchronization tasks, purchase a dedicated cluster. For more information, see What is a DTS dedicated cluster.
      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	The extract, transform, load (ETL) feature is not supported. In this case, No is selected.
      Whether to delete SQL operations on heartbeat tables of forward and reverse tasks	Specifies whether to write SQL operations on heartbeat tables to the source database while the DTS instance is running. Valid values: Yes: does not write SQL operations on heartbeat tables. In this case, a latency of the DTS instance may be displayed. No: writes SQL operations on heartbeat tables. In this case, features such as physical backup and cloning of the source database may be affected.
      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 enable alerting. Yes: configures alerting. In this case, you must also configure the alert threshold and alert notification settings. For more information, see the "Configure monitoring and alerting when you create a DTS task" section of the Configure monitoring and alerting topic.

   3. Click Next: Configure Database and Table Fields. In the Note dialog box that appears, click OK.

      By default, the primary key column of the source table is selected by DTS as the value of the Primary Key Column parameter when you synchronize the source table to the Tablestore instance. To modify the Primary Key Column parameter, set the Definition Status parameter to All.

      Note

      You can select multiple columns for the Primary Key Column parameter from the drop-down list to generate a composite primary key.

4. Click Next: Save Task Settings and Precheck in the lower part of the page.

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

   • If you do not need to view or already 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 data synchronization task fails the precheck, click View Details next to each failed item. After you analyze the causes based on the check results, troubleshoot the issues. Then, rerun the precheck.

   • 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 issues. Then, rerun the precheck.

     • 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 rerun the precheck. If you ignore the alert item, data inconsistency may occur, and your business may be exposed to potential risks.

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

6. Purchase an 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 a subscription when you create a data synchronization instance. The subscription billing method is more cost-effective than the pay-as-you-go billing method for long-term use. Pay-as-you-go: You are charged for the data synchronization instance based on the pay-as-you-go billing method 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 data synchronization instance, you can release the instance to reduce costs.
      	Resource Group Settings	The resource group to which the data synchronization instance belongs. Default value: default resource group. For more information, see What is Resource Management?
      	Instance Class	DTS provides instance classes that vary in synchronization speed. You can select an instance class based on your business requirements. For more information, see Instance classes of data synchronization instances.
      	Subscription Duration	If you select the subscription billing method, specify the subscription duration and the number of data synchronization 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. In the message that appears, click OK.

7. Verify the result.

   1. Log on to the Tablestore console.

   2. In the top navigation bar, select the region in which the Tablestore instance resides and the resource group to which the instance belongs.

   3. On the Overview page, click the name of the Tablestore instance or click Manage Instance in the Actions column.

   4. On the Instance Details tab, click the Tables tab to query the table that you synchronized.