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

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

    Last Updated:May 08, 2025

    This topic describes how to use Data Transmission Service (DTS) to migrate data from an ApsaraDB RDS for SQL Server instance or a self-managed SQL Server database to an AnalyticDB for MySQL cluster. This allows you to transfer data with ease and analyze data in real time.

    Supported source databases

    You can migrate data from the following types of SQL Server databases to an AnalyticDB for MySQL cluster. In this topic, an RDS instance is used as the source database to describe how to configure a data migration task. You can follow the procedure to configure data migration tasks for other types of SQL Server databases.

    • RDS instance

    • 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

    • The new DTS console is used. You can configure a data migration task for this scenario only in the new DTS console.

    • The source RDS instance is created. For more information about supported database engine versions, see Overview of data migration scenarios. For more information about how to create an RDS instance, see Create an ApsaraDB RDS for SQL Server instance.

      Important

      If the RDS instance runs SQL Server 2008 or SQL Server 2008 R2, incremental data migration is not supported.

    • The AnalyticDB for MySQL cluster is created. For more information, see Create a cluster.

    • The storage capacity of the AnalyticDB for MySQL cluster is larger than the storage capacity of the RDS instance.

    • If the RDS instance meets one of the following conditions, we recommend that you split the migration task into multiple subtasks.

      • 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.

    Usage notes

    Note

    • During schema migration, DTS does not migrate foreign keys from the source database to the destination database.

    • During full data migration and incremental data migration, DTS temporarily disables the constraint check and cascade operations on foreign keys at the session level. If you perform the cascade update and delete operations on the source database during data migration, data inconsistency may occur.

    Limit type

    Description

    Limits on the source database

    • The server on which the source database is deployed must have sufficient outbound bandwidth. Otherwise, the data migration speed decreases.

    • The tables to be migrated must have PRIMARY KEY or UNIQUE constraints and all fields must be unique. Otherwise, the destination database may contain duplicate data records.

    • If you select tables as the objects to be migrated and you need to edit the tables in the destination database, such as renaming tables or columns, you can migrate up to 1,000 tables in a single data migration task. If you run a task to migrate more than 1,000 tables, a request error occurs. In this case, we recommend that you configure multiple tasks to migrate the tables or configure a task to migrate the entire database.

    • You can run a single data migration task to migrate up to 10 databases. If you want to migrate more than 10 databases, we recommend that you configure multiple tasks to migrate the databases. Otherwise, the performance and stability of your data migration task may be compromised.

    • If you want to migrate incremental data, make sure that the following requirements are met:

      • The data logging feature must be enabled. The backup mode must be set to Full and full physical backup must be performed.

      • If you perform only incremental data migration, the data logs of the source database must be retained for more than 24 hours. If you perform both full data migration and incremental data migration, the data logs of the source database must be retained for at least seven days. Otherwise, Data Transmission Service (DTS) may fail to obtain the data logs and the task may fail. In some cases, data inconsistency or loss may even occur. After full data migration is complete, you can set the retention period to more than 24 hours. Make sure that you set the retention period of data logs based on the preceding requirements. Otherwise, the Service Level Agreement (SLA) of DTS does not guarantee service reliability or performance.

    • If the change data capture (CDC) feature needs to be enabled for the tables that you want to migrate from the source database, the following conditions must be met. Otherwise, the precheck fails.

      • The value of the srvname field in the sys.sysservers view is the same as the return value of the SERVERPROPERTY function.

      • If the source database is a self-managed SQL Server database, the database owner must be the sa user. If the source database is an ApsaraDB RDS for SQL Server database, the database owner must be the sqlsa user.

      • If the source database is of the Enterprise edition, you must use SQL Server 2008 or later.

      • If the source database is of the Standard edition, you must use SQL Server 2016 SP1 or later.

      • If the source database is of the Standard or Enterprise edition and its version is SQL Server 2017, we recommend that you update the version.

    • DTS uses the fn_log function to obtain the logs of the source database. However, this function has performance bottlenecks. We recommend that you do not clear the logs of the source database before the task is complete. Otherwise, the task may fail.

    • Limits on operations on the source database:

      • During schema migration and full data migration, do not execute DDL statements to change the schemas of databases or tables. Otherwise, the data migration task fails.

      • If you perform only full data migration, do not write data to the source database during data migration. Otherwise, data will be inconsistent between the source and destination databases. To ensure data consistency, we recommend that you select Schema Migration, Full Data Migration, and Incremental Data Migration as the migration types.

    • If the source database is a read-only instance, you cannot migrate DDL operations.

    • If the source database is an Azure SQL Database, only one database can be migrated in a data migration task.

    • If the source database is an ApsaraDB RDS for SQL Server database and incremental data is migrated in the data migration task, make sure that the Transparent Data Encryption (TDE) feature is disabled. This can ensure the instance runs as expected. For more information, see Configure TDE.

    • In hybrid log-based parsing mode, you cannot perform multiple operations to add columns to or remove columns from the source database within 10 minutes. For example, if you execute the following SQL statements within 10 minutes, an error is reported for the task. 

      ALTER TABLE test_table DROP COLUMN Flag;
ALTER TABLE test_table ADD Remark nvarchar(50) not null default('');

    • If the source database is an ApsaraDB RDS for SQL Server instance that runs SQL Server Web edition, you must set the SQL Server Incremental Synchronization Mode parameter to Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported) when you configure the task.

    • We recommend that you enable the transaction processing mode parameter of READ_COMMITTED_SNAPSHOT for the source database during full data migration. Otherwise, it may affect the data-write due to shared locks, data inconsistency may occur, or an instance fails to run. Issues that arise in such circumstances are not covered by the service level agreement (SLA) of DTS.

    Other limits

    • DTS does not migrate the following types of data: CURSOR, ROWVERSION, SQL_VARIANT, HIERARCHYID, POLYGON, GEOMETRY, GEOGRAPHY, and custom data types by running CREATE TYPE command.

    • If DDL statements fail to be executed in the destination database, the DTS task continues to run. You can view the DDL statements that fail to be executed in task logs. For more information about how to view the task logs, see View task logs.

    • You must specify a custom primary key in the destination database or configure Primary Key Column during the Configurations for Databases, Tables, and Columns. Otherwise, data may fail to be migrated.

    • If you set the SQL Server Incremental Synchronization Mode parameter to Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported) in the Configure Objects step, the tables to be migrated must have clustered indexes that contain primary key columns. The tables to be migrated cannot be heap tables, tables without primary keys, compressed tables, or tables with computed columns. Ignore the preceding limits if the hybrid log-based parsing mode is used.

    • If you set the SQL Server Incremental Synchronization Mode parameter to Log-based Parsing for Non-heap Tables and CDC-based Incremental Synchronization for Heap Tables (Hybrid Log-based Parsing) in the Configure Objects step, the following limits apply:

      • DTS uses the CDC component to migrate incremental data. Make sure that the CDC job in the source database runs as expected. Otherwise, the DTS task fails.

      • The CDC component can store the incremental data for 3 days by default. You can adjust the retention period by running the exec console.sys.sp_cdc_change_job @job_type = 'cleanup', @retention= <time>; command.

        Note

        • <time> indicates the retention time. Unit: minutes.

        • If the average daily number of the incremental data in the SQL Server database exceeds 10 million, we recommend setting the <time> parameter to 1,440.

      • We recommend that you specify a data migration task that contains no more than 1,000 tables for which CDC is enabled. Otherwise, the task may be delayed or unstable.

      • The pre-module of an incremental data migration task in DTS enables CDC in the source database. In this process, locked tables that lasts a few seconds occurs in the source database due to the limit of SQL Server database.

    • If you set the SQL Server Incremental Synchronization Mode parameter to Polling and querying CDC instances for incremental synchronization in the Configure Objects step, the following limits apply:

      • The source database account used by the DTS instance must have the permissions to enable the CDC feature. To enable database-level CDC, you must use an account that is assigned the sysadmin role. To enable table-level CDC, you must use a privileged account.

        Note

        • A server administrator account in Microsoft Azure SQL Database has the required permissions. CDC can be enabled for all databases that are purchased in Azure SQL Database based on the vCore model. CDC can be enabled for databases that are purchased in Azure SQL Database based on the database transaction unit (DTU) model only if the databases have a service tier of S3 or greater.

        • A privileged account of an Amazon RDS for SQL Server instance has the required permissions. CDC can be enabled for stored procedures at the database level.

        • CDC cannot be enabled for clustered columnstore indexes.

        • The pre-module of an incremental data migration task in DTS enables CDC in the source database. In this process, locked tables that lasts a few seconds occurs in the source database due to the limit of SQL Server database.

      • DTS obtains incremental data by performing round-robin queries on the CDC instance of each table in the source database. Therefore, the number of tables to be migrated from the source database cannot exceed 1,000. Otherwise, the data migration task may be delayed or unstable.

      • The CDC component can store the incremental data for 3 days by default. You can adjust the retention period by running the exec console.sys.sp_cdc_change_job @job_type = 'cleanup', @retention= <time>; command.

        Note

        • <time> indicates the retention time. Unit: minutes.

        • If the average daily number of the incremental data in the SQL Server database exceeds 10 million, we recommend setting the <time> parameter to 1,440.

      • You cannot execute a DDL statement to add or remove columns more than twice within a minute. Otherwise, the data migration task may fail.

      • During data migration, you cannot modify the CDC instances of the source database. Otherwise, the data migration task may fail or data loss may occur.

    • In Incremental Synchronization Based on Logs of Source Database mode, DTS creates a trigger named dts_cdc_sync_ddl, a heartbeat table named dts_sync_progress, and a DDL history table named dts_cdc_ddl_history in the source database to ensure that the latency of data migration is accurate. In hybrid log-based parsing incremental synchronization mode, DTS creates a trigger named dts_cdc_sync_ddl, a heartbeat table named dts_sync_progress, and a DDL history table named dts_cdc_ddl_history and enables CDC for the source database and specific tables. We recommend that you set the maximum number of records per second to 1,000 for the tables for which CDC is enabled in the source database.

    • Due to the limits of AnalyticDB for MySQL clusters, if the disk space usage of the nodes in an AnalyticDB for MySQL cluster exceeds 80%, the performance of data writing to the destination database is compromised, and the DTS task is delayed. If the disk space usage of the nodes in the AnalyticDB for MySQL cluster exceeds 90%, data cannot be written to the destination database and error messages are returned. We recommend that you estimate the required disk space based on the objects to be migrated. Make sure that the destination cluster has sufficient storage space.

    • If the destination AnalyticDB for MySQL V3.0 cluster is being backed up while the DTS task is running, the DTS task fails.

    • Before you migrate data, evaluate the impact of data migration on the performance of the source and destination databases. We recommend that you migrate data during off-peak hours. During full data migration, DTS uses the read and write resources of the source database and destination cluster. This may increase the loads on the database servers.

    • During full data migration, concurrent INSERT operations cause fragmentation in the tables of the destination database. After full data migration is complete, the size of used tablespace of the destination database is larger than that of the source database.

    • You must make sure that the precision settings for columns of the FLOAT or DOUBLE data type meet your business requirements. DTS uses the ROUND(COLUMN,PRECISION) function to retrieve values from columns of the FLOAT or DOUBLE data type. If you do not specify a precision, DTS sets the precision for columns of the FLOAT data type to 38 digits and the precision for columns of the DOUBLE data type to 308 digits.

    • DTS attempts to resume data migration tasks that failed within the last seven days. Before you switch workloads to the destination database, you must stop or release the failed tasks. You can also execute the REVOKE statement to revoke the write permissions from the accounts that are used by DTS to access the destination database. Otherwise, the data in the source database overwrites the data in the destination database after the failed task is resumed.

    • If the data migration task involves incremental data migration, DTS does not allow you to perform the reindexing operation. If you perform the reindexing operation, the data migration task may fail and data loss may occur.

      Note

      DTS cannot migrate DDL operations related to the primary key of a table for which CDC is enabled.

    • If the number of CDC-enabled tables to be migrated in a single migration task exceeds the maximum number of tables for which CDC is enabled that DTS supports, the precheck fails.

    • If a task contains the incremental data migration, and the tables for which CDC is enabled require data whose size is larger than 64 KB in a single field, run the exec sp_configure 'max text repl size', -1; command in advance to configure the source database.

      Note

      By default, a CDC job can process data with the maximum size of 64 KB.

    • The incremental data collection modules of multiple data migration instances that share a source SQL Server database are independent of each other.

    • If a DTS task fails to run, DTS technical support will try to restore the task within 8 hours. During the restoration, the task may be restarted, and the parameters of the task may be modified.

      Note

      Only the parameters of the task may be modified. The parameters of databases are not modified. The parameters that may be modified include but are not limited to the parameters in the "Modify instance parameters" section of the Modify the parameters of a DTS instance topic.

    Special cases

    If the source instance is an ApsaraDB RDS for SQL Server instance, DTS automatically creates an account named rdsdt_dtsacct on the ApsaraDB RDS for SQL Server instance. This account is used for data migration. Do not delete this account or change the password of this account when your data migration task is running. Otherwise, the task may fail. For more information, see System accounts.

    Billing

    Migration type

    Instance configuration fee

    Internet traffic fee

    Schema migration and full data migration

    Free of charge.

    When the Access Method parameter of the destination database is set to Public IP Address, you are charged for Internet traffic. For more information, see Billing overview.

    Incremental data migration

    Charged. For more information, see Billing overview.

    Migration types

    • Schema migration

      DTS migrates the schemas of the selected 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

      The source and destination databases are heterogeneous databases. The data types that they support do not have one-to-one correspondence. In this case, the task may fail or data loss may occur. 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 historical data of required 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 incrementally migrated

    Operation type

    SQL statement

    DML

    INSERT, UPDATE, and DELETE

    Note

    • If an UPDATE operation updates only the large fields, DTS does not migrate the operation.

    • When data is written to the destination AnalyticDB for MySQL V3.0 cluster, the UPDATE statement is automatically converted to the REPLACE INTO statement. If the UPDATE statement is executed on the primary key, the UPDATE statement is converted to the DELETE and INSERT statements.

    DDL

    • CREATE TABLE

      Note

      If a CREATE TABLE operation creates a partitioned table or a table that contains functions, DTS does not migrate the operation.

    • ALTER TABLE

      ALTER TABLE operations include only ADD COLUMN and DROP COLUMN.

    • DROP TABLE

    • CREATE INDEX and DROP INDEX

    Note

    • DTS does not migrate DDL operations that contain user-defined types.

    • DTS does not migrate transactional DDL operations. For example, DTS does not migrate an SQL operation that contains DDL operations on multiple columns or an SQL operation that contains both DDL operations and DML operations. Data loss may occur after such SQL operations are migrated.

    • DTS does not migrate online DDL operations.

    • DTS does not migrate DDL operations performed on objects whose names contain reserved keywords.

    • DTS does not migrate DDL operations performed in system stored procedures.

    • DTS does not migrate the TRUNCATE TABLE operation.

    Permissions required for database accounts

    Database

    Schema migration

    Full data migration

    Incremental data migration

    RDS instance

    Read permissions on the objects to be migrated

    Read permissions on the objects to be migrated

    Permissions of the object owner

    AnalyticDB for MySQL cluster

    Read and write permissions

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

    Procedure

    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 to go to the task configuration page.

    3. 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 Existing Connection

      • If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections.

        Note

        In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list.

      • If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.

      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 RDS instance resides.

      Replicate Data Across Alibaba Cloud Accounts

      Specifies whether to migrate data across Alibaba Cloud accounts. Select No.

      RDS Instance ID

      The ID of the RDS instance.

      Database Account

      The database account of the RDS instance. For more information about the permissions that are required for the account, 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. Select Non-encrypted or SSL-encrypted based on your business requirements.

      • If SSL encryption is disabled for the source database, select Non-encrypted.

      • If SSL encryption is enabled for the source database, select SSL-encrypted. By default, DTS trusts the server certificate.

      Destination Database

      Select Existing Connection

      • If you use a database instance that is registered with DTS, select the instance from the drop-down list. DTS automatically populates the following database parameters for the instance. For more information, see Manage database connections.

        Note

        In the DMS console, you can select the database instance from the Select a DMS database instance drop-down list.

      • If you fail to register the instance with DTS, or you do not need to use the instance that is registered with DTS, you must configure the following database information.

      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

      Select the region in which the AnalyticDB for MySQL V3.0 cluster resides.

      Instance ID

      The ID of the AnalyticDB for MySQL V3.0 cluster.

      Database Account

      The database account of the AnalyticDB for MySQL V3.0 cluster. For more information about the permissions that are required for the account, see Permissions required for database accounts.

      Database Password

      The password that is used to access the database instance.

    4. 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.

      • If the source or destination database is a self-managed database and its Access Method is not set to Alibaba Cloud Instance, click Test Connectivity in the CIDR Blocks of DTS Servers dialog box.

    5. Configure the objects to be migrated.

      1. On the Configure Objects page, configure the objects that you want to migrate.

        Parameter

        Description

        Migration Types

        • To perform only full data migration, select Schema Migration and Full Data Migration.

        • To migrate data without service downtime, 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 using 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 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 Database, table, and column name mapping.

        • 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.

        Schema Mapping Mode of Source and Destination Databases

        Select a schema mapping mode based on your business requirements.

        Warning

        If you do not use the schema names of the source database, the source tables must have unique names across different schemas. Otherwise, data inconsistency may occur or the data synchronization task may fail.

        SQL Server Incremental Synchronization Mode

        • Log-based Parsing for Non-heap Tables and CDC-based Incremental Synchronization for Heap Tables (Hybrid Log-based Parsing):

          • Advantages:

            • This mode supports heap tables, tables without primary keys, compressed tables, and tables with computed columns.

            • This mode provides higher stability and a variety of complete DDL statements.

          • Disadvantages:

            • DTS creates the trigger dts_cdc_sync_ddl, the heartbeat table dts_sync_progress, and the DDL storage table 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, TRUNCATE, or RENAME COLUMN statement on tables with CDC enabled in the source database. Triggers created by DTS in the source database cannot be manually deleted.

        • Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported):

          • Advantages:

            This mode does not modify the settings of the source database.

          • Disadvantages:

            This mode does not support heap tables, tables without primary keys, compressed tables, or tables with computed columns.

        • Polling and querying CDC instances for incremental synchronization:

          • Advantages:

            • Full data migration and incremental data migration are supported if the source database is an Amazon RDS for SQL Server instance, a database in Microsoft Azure SQL Database, a Microsoft Azure SQL Managed Instance, a Microsoft Azure SQL Server on Virtual Machine, or a Google Cloud SQL for SQL Server instance.

            • If you use the native CDC component of SQL Server to obtain incremental data, incremental migration is more stable and occupies less network bandwidth.

          • Disadvantages:

            • The source database account that is used by the DTS instance must have the permission to enable CDC. Incremental data migration takes about 10 seconds.

            • If you migrate multiple tables in multiple databases, stability and performance issues may occur.

        Note

        You can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.

        The maximum number of tables for which CDC is enabled that DTS supports.

        We recommend that you, based on your business requirements, set the maximum number of tables for which CDC is enabled that a DTS task supports. Default value: 1,000.

        Note

        This parameter is unavailable if you set the SQL Server Incremental Synchronization Mode parameter to Incremental Synchronization Based on Logs of Source Database (Heap tables are not supported).

        DDL and DML Operations to Be Synchronized

        The SQL operations to be migrated during incremental data migration at the instance level. For more information, see SQL operations that can be incrementally migrated.

        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. Click the 向右小箭头 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.

        Selected Objects

        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.

        • To specify WHERE conditions to filter data, right-click an object in the Selected Objects section. In the dialog box that appears, specify the conditions. For more information about how to specify the conditions, see Specify filter conditions.

        • 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 migrate.

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

        Parameter

        Description

        Dedicated Cluster for Task Scheduling

        By default, DTS schedules the data migration task to the shared cluster if you do not specify a dedicated cluster. If you want to improve the stability of data migration 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 migration task is started, DTS immediately retries a connection within the retry time range. Valid values: 10 to 1,440. 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 the earliest opportunity after the source database and destination instance 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 uses the read and write resources of the source and destination databases. This may increase the loads of the database servers. You can enable throttling for full data migration based on your business requirements. To configure 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 reduces the loads of the destination database server.

        Note

        You can configure this parameter only if you select Full Data Migration for the Migration Types parameter.

        Enable Throttling for Incremental Data Migration

        Specifies whether to enable throttling for incremental data migration. To configure throttling, you must configure the RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) parameters. This reduces the loads of the destination database server.

        Note

        You can configure this parameter only if you select Incremental Data Migration for the Migration Types parameter.

        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:

        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:

      3. Click Next Step: Data Verification to configure the data verification task.

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

      4. Optional: In the lower part of the page, click Next: Configure Database and Table Fields. In the dialog box that appears, configure the Type, Primary Key Column, Distribution Key, and parameters about partition keys such as Partition Key, Partitioning Rules, and Partition Lifecycle for the tables to be migrated to the destination database.

        Note

        • This step is available only if you select Schema Migration for the Migration Types parameter. To modify the parameter, set the Definition Status as All.

        • 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 keys and partition keys. For more information, see CREATE TABLE.

    6. 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 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.

    7. Purchase an instance.

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

      2. 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.

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

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

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

        Note

        • If a data migration task cannot be used to migrate incremental data, the task automatically stops. The Completed is displayed in the Status section.

        • If a data migration task can be used to migrate incremental data, the task does not automatically stop. The incremental data migration task never stops or completes. The Running is displayed in the Status section.