ApsaraDB RDS:Migrate data from a Baidu AI Cloud RDS for MySQL instance to an ApsaraDB RDS for MySQL instance

Prerequisites

Limits

• The schema migration method does not support events.

• Data Transmission Service (DTS) reads floating-point values of the FLOAT and DOUBLE data types in MySQL by calling the round(column,precision) function. If the value precision is not specified by the data type of a column, the precision is 38 bits for FLOAT-type values and 308 bits for DOUBLE-type values. You must check whether the precision of FLOAT-type and DOUBLE-type values that need to be migrated by DTS meets your business requirements.

• If you use the object name mapping feature on an object, other objects that are dependent on the object may fail to be migrated.

• If incremental data migration is used, binary logging must be enabled for the Baidu AI Cloud RDS for MySQL instance.

• If incremental data migration is used, the binlog_format parameter of the source database must be set to row.

• If incremental data migration is used and the Baidu AI Cloud RDS for MySQL instance runs MySQL 5.6 or later, the binlog_row_image parameter of the instance must be set to full.

• If incremental data migration is used and cross-host migration or reconstruction is performed on the Baidu AI Cloud RDS for MySQL instance during the incremental data migration, the IDs of binary log files may be disordered and the incremental data that is migrated may be lost.

Usage notes

DTS attempts to automatically resume abnormal migration tasks that are run within seven days. In this case, data on the Baidu AI Cloud RDS for MySQL instance may overwrite the service data that is written to the ApsaraDB RDS for MySQL instance. After a migration task is complete, you must execute the REVOKE statement to revoke the write permissions of the DTS account that is used to access the ApsaraDB RDS for MySQL instance.

Procedure (in the new DTS console)

1. Use one of the following methods to go to the Data Migration page and select the region in which the data migration instance resides.

   DTS console

   1. Log on to the DTS console.

   2. In the left-side navigation pane, click Data Migration.

   3. In the upper-left corner of the page, select the region in which the data migration instance resides.

   DMS console

   Note

   The actual operation 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.

   1. Log on to the DMS console.

   2. In the top navigation bar, move the pointer over Data + AI > DTS (DTS) > Data Migration .

   3. From the drop-down list to the right of Data Migration Tasks, select the region in which the data synchronization instance resides.

2. Click Create Task. On the Create Data Synchronization Task page, configure the source and destination databases. The following table describes the parameters.

   Warning

   After you configure the source and destination databases, we recommend that you read the Limits that are displayed in the upper part of the page. Otherwise, the task may fail or data inconsistency may occur.

   Section	Parameter	Description
   N/A	Task Name	The name of the DTS task. DTS automatically generates a task name. We recommend that you specify an informative 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 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 instance. In this example, MySQL is selected.
   	Access Method	The method that is used by the source instance to access DTS. In this example, Public IP Address is selected.
   	Instance Region	The region of the source instance. Note If you cannot find the region in which the source instance resides, you can select a region that is closest to the instance.
   	Domain Name or IP	The endpoint of the source instance. Note In the network connections section of the Basic info page of the Baidu AI Cloud RDS for MySQL instance, click Get IP to obtain the IPv4 address of the Baidu AI Cloud RDS for MySQL instance.
   	Port Number	The port number of the source instance. Default value: 3306. Note In the network connections section of the Basic info page, view the value of the Port parameter.
   	Database Account	The database account of the source instance. For more information about account permissions, see Permissions required for database accounts.
   	Database Password	The password that is used to access the database instance.
   Destination Database	Select a DMS database instance	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 instance. In this example, MySQL is selected.
   	Access Method	The method that is used by the destination instance to access DTS. In this example, Alibaba Cloud Instance is selected.
   	Instance Region	The region of the destination instance.
   	Replicate Data Across Alibaba Cloud Accounts	Specifies whether data is migrated across Alibaba Cloud accounts. In this example, No is selected.
   	RDS Instance ID	The ID of the destination instance.
   	Database Account	The database account of the destination instance. For information about the account permissions, see Permissions required for database accounts.
   	Database Password	The password that is used to access the database instance.
   	Encryption	Specifies whether to encrypt the connection to the source database instance. Select Non-encrypted or SSL-encrypted based on your business requirements. If you want to set this parameter to SSL-encrypted, you must enable SSL encryption for the ApsaraDB RDS for MySQL instance before you configure the DTS task. For more information, see Use a cloud certificate to enable SSL encryption.

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

   Note

   Make sure that the CIDR blocks of DTS servers can be automatically or manually added to the security settings of the source and destination databases to allow access from DTS servers. For more information, see Add the CIDR blocks of DTS servers.

4. If an IP address whitelist is configured for your self-managed database, add the CIDR blocks of DTS servers to the IP address whitelist. Then, click Test Connectivity.

   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 migrate 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 forbidding unauthorized CIDR blocks, or connecting the database instance to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

5. Configure the objects that you want to synchronize and the advanced settings. The following table describes the parameters.

   Parameter	Description
   Migration Types	To perform only full data migration, select Schema Migration and Full Data Migration. To ensure service continuity during data migration, select Schema Migration, Full Data Migration, and Incremental Data Migration. Note If you do not select Schema Migration, make sure a database and a table are created in the destination database to receive data and the object name mapping feature is enabled in Selected Objects. If you do not select Incremental Data Migration, we recommend that you do not write data to the source database during data migration. This ensures data consistency between the source and destination databases.
   Processing Mode of Conflicting Tables	Precheck and Report Errors: checks whether the destination database contains tables that use 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 migration 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 migrated 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 the following potential risks: If the source and destination databases have the same schema, and a data record has the same primary key as an existing data record in the destination database, the following scenarios may occur: During full data migration, DTS does not migrate the data record to the destination database. The existing data record in the destination database is retained. During incremental data migration, DTS migrates 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, only specific columns are migrated or the data migration task fails. Proceed with caution.
   Method to Migrate Triggers in Source Database	The method that is used to migrate triggers from the source database. You can select a migration method based on your business requirements. If no triggers are involved, you can ignore this parameter. For more information, see Synchronize or migrate triggers from the source database. Note You can configure this parameter only when you set the Migration Types parameter to Schema Migration.
   Enable Migration Assessment	Specifies whether to enable migration assessment. The migration assessment is used to check whether the schemas of the source and destination databases, such as the index length, stored procedures, and dependent tables, meet the requirements. You can select Yes or No based on your business requirements. Note You can configure this parameter only when you set the Migration Types parameter to Schema Migration. If you select Yes, the period of time that is required for the precheck may increase. You can view the Assessment Result during the precheck. The assessment results do not affect the precheck results.
   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 make sure that the capitalization of object names is consistent with that of 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. Click the icon and add the objects to the Selected Objects section. Note You can select columns, tables, or schemas as the objects to be migrated. If you select tables or columns as the objects to be migrated, DTS does not migrate other objects, such as views, triggers, or stored procedures, to the destination database.
   Selected Objects	To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Map the name of a single object. To rename multiple objects at a time, click Batch Edit in the upper-right corner of the Selected Objects section. For more information, see Map multiple object names at a time. Note If you use the object name mapping feature to rename an object, other objects that are dependent on the object may fail to be migrated. If you use the WHERE clause to filter data, you need to right-click a table in the Selected Objects section and specify the filter conditions in the dialog box that appears. For more information, see Set filter conditions. If you want to migrate the SQL operations performed on a specific database or table, you need to right-click the object in the Selected Objects section and select the SQL operations that you want to migrate in the dialog box that appears.

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

   • Data Verification Settings

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

   • Advanced Settings

     Parameter	Description
     Dedicated Cluster for Task Scheduling	By default, DTS schedules tasks to shared clusters. You do not need to configure this parameter. You can purchase a dedicated cluster of specific specifications to run data migration tasks. For more information, see What is a DTS dedicated cluster?
     Monitoring and Alerting	Specifies whether to configure alerting for the data migration task. If the task fails or the migration latency exceeds the specified threshold, the alert contacts 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 the Configure monitoring and alerting when you create a DTS task section of the Configure monitoring and alerting topic.
     Copy the temporary table of the Online DDL tool that is generated in the source table to the destination database.	If you use DMS or the gh-ost tool to perform online DDL operations on the source database, you can specify whether to migrate the data of temporary tables generated by online DDL operations. Valid values: Important You cannot use tools such as pt-online-schema-change to perform online DDL operations on the source database. Otherwise, the DTS task fails. Yes: DTS migrates the data of temporary tables generated by online DDL operations. Note If online DDL operations generate a large amount of data, latency may occur for the data migration task. No, Adapt to DMS Online DDL: DTS does not migrate the data of temporary tables generated by online DDL operations. Only the original DDL operations that are performed by using DMS are migrated. Note If you select this option, the tables in the destination database may be locked. No, Adapt to gh-ost: DTS does not migrate the data of temporary tables generated by online DDL operations. Only the original DDL operations that are performed by using the gh-ost tool are migrated. You can use the default or custom regular expressions to filter out the shadow tables of the gh-ost tool and tables that are not required. Note If you select this option, the tables in the destination database may be locked.
     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 DDL or DML operations fail to be performed after the data migration task is started, DTS immediately retries the operations within the retry time range. Valid values: 1 to 1440. Unit: minutes. Default value: 10. We recommend that you set the parameter to a value greater than 10. If the failed operations are successfully performed within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration 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	Specifies whether to enable throttling for full data migration. During full data migration, DTS occupies the read and write resources of the source and destination databases. This may increase the loads of the databases. You can enable throttling for full data migration based on your business requirements. To enable throttling, you must 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. This helps offload the destination instance. Note You can configure this parameter only when you set the Migration Types parameter to Full Data Migration.
     Enable Throttling for Incremental Data Migration	You can enable throttling for incremental data migration based on your business requirements. To enable throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This helps offload the destination instance. Note You can configure this parameter only when you set the Migration Types parameter to Incremental Data Migration.
     Environment Tag	The environment tag that is used to identify the 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.
     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.

7. In the lower part of the page, click Next: Save Task Settings and Precheck.

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

   Note

   • Before you can start the data migration task, DTS performs a precheck. You can start the data migration 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 triggered for an item during the precheck:

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

     • If the 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.

8. Wait until Success Rate becomes 100%. Then, click Next: Purchase Instance.

9. On the Purchase Instance page, configure the Instance Class parameter for the data migration instance. The following table describes the parameters.

   Section	Parameter	Description
   New Instance Class	Resource Group	The resource group to which the data migration instance belongs. Default value: default resource group. For more information, see What is Resource Management?
   	Instance Class	DTS provides instance classes that vary in the migration speed. You can select an instance class based on your business scenario. For more information, see Instance classes of data migration instances.

10. Read and agree to Data Transmission Service (Pay-as-you-go) Service Terms by selecting the check box.

11. Click Buy and Start. In the message that appears, click OK.

    You can view the progress of the task on the Data Migration page.