ApsaraDB RDS:Migrate data from an ApsaraDB RDS for SQL Server instance to an AnalyticDB for MySQL V3.0 cluster

Supported source databases

• ApsaraDB RDS for SQL Server instances
• Self-managed databases:
  • Self-managed database with a public IP address
  • Self-managed database that is hosted on Elastic Compute Service (ECS)
  • Self-managed database that is connected over Express Connect, VPN Gateway, or Smart Access Gateway
  • Self-managed database that is connected over Database Gateway

Prerequisites

• You can configure a data migration task for this scenario only in the new DTS console.
• The source ApsaraDB RDS for SQL Server instance is created. For more information, see Overview of data migration scenarios and Create an ApsaraDB RDS for SQL Server instance.
  Important If the database version of the ApsaraDB RDS for SQL Server instance is 2008 or 2008 R2, incremental data migration is not supported.
• The destination AnalyticDB for MySQL V3.0 cluster is created. For more information, see Create a cluster.
• The available storage space of the destination AnalyticDB for MySQL V3.0 cluster is larger than the total size of the data in the source ApsaraDB RDS for SQL Server instance.
• If the source database meets one of the following conditions, we recommend that you migrate data by using the backup feature of ApsaraDB RDS for SQL Server. For more information, see Migrate data from a self-managed database to ApsaraDB RDS for SQL Server.

  • The source instance contains more than 10 databases.

  • A single database of the source instance backs up its logs at an interval of less than 1 hour.

  • A single database of the source instance executes more than 100 DDL statements each hour.

  • Logs are written at a rate of 20 MB/s for a single database of the source instance.

  • The change data capture (CDC) feature needs to be enabled for more than 1,000 tables in the source ApsaraDB RDS for SQL Server instance.

  • The logs of a database in the source ApsaraDB RDS for SQL Server instance involve heap tables, tables without primary keys, compressed tables, or tables with computed columns. You can execute the following SQL statements to check whether the source database contains these tables.

    1. Execute the following SQL statement to check for heap tables:

       SELECT s.name AS schema_name, t.name AS table_name FROM sys.schemas s INNER JOIN sys.tables t ON s.schema_id = t.schema_id AND t.type = 'U' AND s.name NOT IN ('cdc', 'sys') AND t.name NOT IN ('systranschemas') AND t.object_id IN (SELECT object_id FROM sys.indexes WHERE index_id = 0);

    2. Execute the following SQL statement to check for tables without primary keys:

       SELECT s.name AS schema_name, t.name AS table_name FROM sys.schemas s INNER JOIN sys.tables t ON s.schema_id = t.schema_id AND t.type = 'U' AND s.name NOT IN ('cdc', 'sys') AND t.name NOT IN ('systranschemas') AND t.object_id NOT IN (SELECT parent_object_id FROM sys.objects WHERE type = 'PK');

    3. Execute the following SQL statement to check for primary key columns that are not contained in clustered index columns:

       SELECT s.name AS schema_name, t.name AS table_name FROM sys.schemas s INNER JOIN sys.tables t ON s.schema_id= t.schema_id WHERE t.type= 'U' AND s.name NOT IN('cdc', 'sys')  AND t.name NOT IN('systranschemas')  AND t.object_id IN (SELECT pk_columns.object_id AS object_id FROM (select sic.object_id object_id, sic.column_id FROM sys.index_columns sic, sys.indexes sis WHERE sic.object_id= sis.object_id AND sic.index_id= sis.index_id AND sis.is_primary_key= 'true') pk_columns LEFT JOIN (SELECT sic.object_id object_id, sic.column_id FROM sys.index_columns sic, sys.indexes sis WHERE sic.object_id= sis.object_id AND sic.index_id= sis.index_id AND sis.index_id= 1) cluster_colums ON pk_columns.object_id= cluster_colums.object_id WHERE pk_columns.column_id != cluster_colums.column_id);

    4. Execute the following SQL statement to check for compressed tables:

       SELECT s.name AS schema_name, t.name AS table_name FROM sys.objects t, sys.schemas s, sys.partitions p WHERE s.schema_id = t.schema_id AND t.type = 'U' AND s.name NOT IN ('cdc', 'sys') AND t.name NOT IN ('systranschemas') AND t.object_id = p.object_id AND p.data_compression != 0;

    5. Execute the following SQL statement to check for tables with computed columns:

       SELECT s.name AS schema_name, t.name AS table_name FROM sys.schemas s INNER JOIN sys.tables t ON s.schema_id = t.schema_id AND t.type = 'U' AND s.name NOT IN ('cdc', 'sys') AND t.name NOT IN ('systranschemas') AND t.object_id IN (SELECT object_id FROM sys.columns WHERE is_computed = 1);

Limits

Billing

Migration types

• Schema migration

  DTS migrates the schemas of objects from the source database to the destination database.

  • DTS supports schema migration for the following types of objects: schema, table, view, function, and procedure.
  • DTS does not migrate the schemas of assemblies, service brokers, full-text indexes, full-text catalogs, distributed schemas, distributed functions, Common Language Runtime (CLR) stored procedures, CLR scalar-valued functions, CLR table-valued functions, internal tables, systems, or aggregate functions.
  Warning ApsaraDB RDS for SQL Server and AnalyticDB for MySQL are heterogeneous databases. The data types that they support do not have one-to-one correspondence. We recommend that you evaluate the impact of data type conversion on your business. For more information, see Data type mappings between heterogeneous databases.

• Full data migration

  DTS migrates the existing data of objects from the source database to the destination database.

• Incremental data migration

  After full data migration is complete, DTS migrates incremental data from the source database to the destination database. Incremental data migration allows data to be migrated smoothly without interrupting the services of self-managed applications during data migration.

SQL operations that can be migrated during incremental data migration

Permissions required for database accounts

For more information about how to create a database account and grant permissions to the database account, see the following topics:

• ApsaraDB RDS for SQL Server instance: Create a privileged account or a standard account and Modify the permissions of an account
• AnalyticDB for MySQL V3.0 cluster: Create a database account

Procedure

1. Go to the Data Migration Tasks page.
   1. Log on to the Data Management (DMS) console.
   2. In the top navigation bar, click DTS.
   3. In the left-side navigation pane, choose DTS (DTS) > Data Migration.
   Note

   • Operations 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 Migration Tasks page of the new DTS console.
2. From the drop-down list next to Data Migration Tasks, select the region in which the data migration instance resides.
   Note If you use the new DTS console, you must select the region in which the data migration instance resides in the upper-left corner.
3. Click Create Task. In the Create Task wizard, configure the source and destination databases.
   
   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 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	Database Type	The type of the source database. Select SQL Server.
   	Access Method	The access method of the source database. Select Alibaba Cloud Instance.
   	Instance Region	The region in which the source ApsaraDB RDS for SQL Server instance resides.
   	Instance ID	The ID of the source ApsaraDB RDS for SQL Server instance.
   	Database Account	The database account of the source ApsaraDB RDS for SQL Server instance. For more information about the permissions that are required for the account, see Permissions required for database accounts.
   	Database Password	The password of the database account.
   Destination Database	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 information about the permissions that are required for the account, see Permissions required for database accounts.
   	Database Password	The password of the database account.

4. 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 IP address 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 self-managed database is hosted 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 IP address 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 to the security settings of on-premises databases topic.

   Warning

   If the public CIDR blocks of DTS servers are automatically or manually added to the IP address 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 account and password, limiting the ports that are exposed, authenticating API calls, regularly checking the IP address whitelist or ECS security group rules and forbidding unauthorized CIDR blocks, and connecting the database to DTS by using Express Connect, VPN Gateway, or Smart Access Gateway.

5. Configure the objects to be migrated and advanced settings.
   
   • Basic Settings

     Parameter or setting	Description
     Migration Types	If you want to perform only full data migration, select Schema Migration and Full Data Migration. If you want to ensure service continuity during data migration, select Schema Migration, Full Data Migration, and Incremental Data Migration. Note If Full Data Migration is selected, you can migrate the schema and data of the table that is created by executing the CREATE TABLE statement to the destination database. If Incremental Data Migration is not selected, we recommend that you do not write data to the source instance during data migration. This ensures data consistency between the source and destination instances.
     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 migration task cannot be started. Note You can use the object name mapping feature to rename the tables that are migrated to the destination database. You can use this feature if the source and destination databases contain tables that have identical table names and the tables in the destination database cannot be deleted or renamed. 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 schemas, DTS does not migrate data records that have the same primary key values as data records in the destination database. If the source and destination databases have different schemas, only specific columns are migrated or the data migration task fails. Proceed with caution.
     SQL Server Incremental Synchronization Mode	Log-based Parsing for Non-heap Tables and CDC-based Incremental Synchronization for Heap Tables: Benefits: Supports heap tables, tables without primary keys, compressed tables, and tables with computed columns. Provides higher stability and a variety of complete DDL statements. Limits: DTS creates the trigger named dts_cdc_sync_ddl, the heartbeat table named dts_sync_progress, and the DDL storage table named dts_cdc_ddl_history in the source database, and enables change data capture (CDC) for the source database and specific tables. You cannot execute the SELECT INTO statement on a table for which CDC is enabled in the source database. You cannot manually delete triggers that are created by DTS in the source database. Incremental Synchronization Based on Logs of Source Database: Benefits: Does not modify the settings of the source database. Limits: Does not support heap tables, tables without primary keys, compressed tables, or tables with computed columns.
     DDL and DML Operations to Be Synchronized	The SQL operations to be migrated at the instance level. For more information, see SQL operations that can be migrated during incremental data migration. Note To select the SQL operations performed on a specific database or table, right-click an object in the Selected Objects section. In the dialog box that appears, select the SQL operations that you want to incrementally migrate.
     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 In this scenario, data migration is performed between heterogeneous databases. Therefore, only tables can be migrated. Other objects such as views, triggers, or stored procedures are not migrated to the destination database.
     Rename Databases and Tables	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 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 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.
     Filter data	You can specify WHERE conditions to filter data. For more information, see Set filter conditions.
     Select the SQL operations to be incrementally migrated	In the Selected Objects section, right-click an object. In the dialog box that appears, select the DDL and DML operations that you want to migrate. For more information, see SQL operations that can be migrated during incremental data migration.

   • Advanced Settings

     Parameter	Description
     Set Alerts	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 will receive notifications. Valid values: No: does not configure alerting. Yes: configures alerting. If you select Yes, you must also specify the alert threshold and alert contacts. For more information, see Configure monitoring and alerting.
     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 migration task is started, DTS immediately retries a connection within the retry time range. Valid values: 10 to 1440. Unit: minutes. Default value: 720. We recommend that you set the parameter to a value greater than 30. If DTS is reconnected to the source and destination databases within the specified retry time range, DTS resumes the data migration task. Otherwise, the data migration task fails. Note If you specify different retry time ranges for multiple data migration tasks that share the same source or destination database, the value that is specified later 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.
     Configure ETL	Specifies whether to configure 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 synchronization task. No: does not configure the ETL feature.

6. Specify the primary key columns and distribution key columns of the tables that you want to migrate to the destination AnalyticDB for MySQL cluster.

   Note

   • If you select Schema Migration as Migration Types, you must configure the Type, Primary Key Column, and Distribution Key parameters for the tables that you want to migrate to the AnalyticDB for MySQL V3.0 cluster. For more information, see CREATE TABLE.

   • In the Primary Key Column field, you can select multiple columns to form a composite primary key. In this case, you must select one or more primary key columns as distribution key columns.

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 troubleshoot the issues based on the error message, you can run a precheck again.

   • If an alert is triggered for an item during the precheck:

     • If the 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 the 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 Specifications 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 to start the data migration task. You can view the progress of the task in the task list.