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    Data Transmission Service:Migrate ApsaraDB RDS for MySQL to DataHub

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    Data Transmission Service:Migrate ApsaraDB RDS for MySQL to DataHub

    Last Updated:Jul 17, 2026

    This topic describes how to use Data Transmission Service (DTS) to migrate data from an ApsaraDB RDS for MySQL instance to DataHub.

    Prerequisites

    Limitations

    Type

    Description

    Source database limits

    • Bandwidth requirement: The server hosting the source database must have sufficient outbound bandwidth. Otherwise, migration speed will drop.

    • Each table to migrate must have a primary key or UNIQUE constraint, and the key columns must contain unique values. Otherwise, duplicate records may appear in the destination database.

    • If you select tables as the migration objects and edit them—for example, by mapping column names—a single migration task supports up to 1,000 tables. If you exceed this limit, the task fails with an error when submitted. To fix this, split the tables across multiple tasks or configure a full-database migration task.

    • If you need incremental migration, enable binary logging:

      • Set binlog_format to ROW and binlog_row_image to FULL. Otherwise, the precheck fails and the task cannot start.

        Important

        If your self-managed MySQL source is a dual-master cluster—where each instance acts as both master and slave—enable the log_slave_updates parameter. This ensures DTS can read all binary logs.

      • For RDS for MySQL instances, retain local binary logs for at least three days (seven days recommended). For self-managed MySQL databases, retain local binary logs for at least seven days. If DTS cannot access binary logs, the task fails. In extreme cases, data inconsistency or data loss may occur. Issues caused by binary log retention periods shorter than DTS requires are not covered under the DTS SLA.

        Note

        To set the retention period for local binary logs on an RDS for MySQL instance, see Automatically delete local logs.

    • Executing DDL operations that modify the database or table schema during the schema migration phase will cause the data migration task to fail.

    • DTS does not migrate data generated by changes that do not write to binary logs. Examples include data restored from physical backups or created by cascade operations.

      Note

      If this occurs, re-run full migration after your business allows it.

    • If your source MySQL database is version 8.0.23 or later and contains invisible hidden columns, DTS cannot read those columns. This may cause data loss.

      Note

      Run ALTER TABLE <table_name> ALTER COLUMN <column_name> SET VISIBLE; to make the hidden column visible. For more information, see Invisible Columns.

    • MySQL compatibility: When DTS migrates data from a MySQL-family source database, it relies on the standard MySQL protocol and Binlog format, and behaviors incompatible with standard MySQL are not supported. If your source database claims MySQL compatibility but behaves differently from MySQL (for example, when OceanBase is connected as a source in MySQL mode, the timestamp of the trailing rotate event in the Binlog is 0, which differs from MySQL), the DTS migration task may fail.

    Other limits

    • Only table-level migration is supported.

    • DTS does not support migrating INDEX, PARTITION, VIEW, PROCEDURE, FUNCTION, TRIGGER, or FK objects.

    • A single String field in the destination DataHub project supports up to 2 MB.

    • Do not use tools such as pt-online-schema-change to run online DDL operations on migration objects in the source database. Otherwise, migration fails.

    • You can use Data Management (DMS) to run online DDL operations. For instructions, see Online schema changes without locking tables.

      Warning

      If data other than DTS writes to the destination database, do not use DMS to run online DDL operations. Otherwise, destination data may be lost.

    • Confirm that DTS migration precision for FLOAT or DOUBLE columns meets your business needs. DTS reads these columns using ROUND(COLUMN,PRECISION). If no precision is defined, DTS uses 38 digits for FLOAT and 308 digits for DOUBLE.

    • DTS tries to recover failed tasks within seven days. Before switching traffic to the destination instance, end or release the task. Or run the revoke command to remove DTS’s write permission on the destination instance account. This prevents automatic recovery from overwriting destination data with source data.

    • If your RDS for MySQL instance has Always-Encrypted enabled, full migration is not supported.

      Note

      RDS for MySQL instances with Transparent Data Encryption (TDE) enabled support schema migration, full migration, and incremental migration.

    • If a task fails, DTS support staff will attempt to restore it within eight hours. During restoration, they may restart the task or adjust its parameters.

      Note

      Only DTS task parameters are modified—not database parameters. Parameters that may be adjusted include those listed in Modify instance parameters.

    Special cases

    • For self-managed MySQL sources:

      • A master–standby switchover on the source database causes the migration task to fail.

      • DTS calculates latency by comparing the timestamp of the last record migrated to the destination database with the current time. If no DML operations run on the source for a long time, latency reporting becomes inaccurate. If latency appears too high, run a DML operation on the source to update the latency value.

        Note

        If you select full-database migration, create a heartbeat table. Update or write to it every second.

      • DTS periodically runs CREATE DATABASE IF NOT EXISTS `test` on the source database to advance the binary log offset.

      • If your source is Amazon Aurora MySQL or another clustered MySQL instance, ensure the domain name or IP address configured for the task—and its DNS resolution—always points to a read–write (RW) node. Otherwise, the migration task may fail.

    • For RDS for MySQL sources:

      • If you need incremental migration, RDS for MySQL instances that do not record transaction logs—such as RDS for MySQL 5.6 read-only instances—are not supported as sources.

      • DTS periodically runs CREATE DATABASE IF NOT EXISTS `test` on the source database to advance the binary log offset.

    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 schema definitions of the migration objects from the source database to the destination database.

    • Full migration

      DTS migrates all historical data of the specified migration objects from the source database to the destination database.

    • Incremental migration

      After a full migration is complete, DTS migrates incremental data updates from the source database to the destination database. Incremental migration lets you smoothly migrate data without interrupting your self-managed applications.

    SQL operations supported for incremental migration

    Operation type

    SQL statement

    DML

    INSERT, UPDATE, DELETE

    DDL

    ADD COLUMN

    Important

    If you manually modify the table structure in the target database, restart the task: pause and then start the task.

    Database account permissions

    Database

    Permissions

    Source ApsaraDB RDS for MySQL instance

    Read permissions on the objects to be migrated.

    Procedure

    1. Navigate to the migration task list page for the destination region using one of the following methods.

      From the DTS console

      1. Log on to the Data Transmission Service (DTS) console.

      2. In the navigation pane on the left, click Data Migration.

      3. In the upper-left corner of the page, select the region where the migration instance is located.

      From the DMS console

      Note

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

      1. Log on to the Data Management (DMS) console.

      2. In the top menu bar, choose Data + AI > Data Transmission (DTS) > Data Migration.

      3. To the right of Data Migration Tasks, select the region where the migration instance is located.

    2. Click Create Task to navigate to the task configuration page.

    3. Configure the source and destination databases.

      Warning

      After you select the source and destination instances, review the Limits at the top of the page. Otherwise, the task may fail or data inconsistency may occur.

      Section

      Parameter

      Description

      N/A

      Task Name

      DTS automatically generates a task name. We recommend that you specify a descriptive name for easy identification. The name does not need to be unique.

      Source Database

      Select Existing Connection

      • To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured.

        Note

        In the DMS console, this parameter is named Select a DMS database instance..

      • If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.

      Database Type

      Select MySQL.

      Connection Type

      Select Alibaba Cloud.

      Instance Region

      Select the region where the source ApsaraDB RDS for MySQL instance resides.

      Cross-account

      Because this scenario migrates data within the same Alibaba Cloud account, select No.

      RDS Instance ID

      Select the ID of the source ApsaraDB RDS for MySQL instance.

      Database Account

      Enter the database account for the source ApsaraDB RDS for MySQL instance. For permission requirements, see Database account permissions.

      Database Password

      Enter the password for the specified database account.

      Encryption

      Select Non-encrypted or SSL-encrypted as needed. If you set this to SSL-encrypted, you must enable SSL encryption for the RDS for MySQL instance beforehand. For more information, see Use a cloud certificate to quickly enable SSL link encryption.

      Destination Database

      Select Existing Connection

      • To use a database instance that has been added to the system (created or saved), select the desired database instance from the drop-down list. The database information below will be automatically configured.

        Note

        In the DMS console, this parameter is named Select a DMS database instance..

      • If you have not registered the database instance with the system, or do not need to use a registered instance, manually configure the database information below.

      Database Type

      Select DataHub.

      Connection Type

      Select Alibaba Cloud.

      Instance Region

      Select the region where the DataHub instance resides.

      Project

      Select the destination DataHub Project.

    4. After you complete the configuration, click Test Connectivity and Proceed at the bottom of the page.

      Note

      • Ensure that the IP address segment of the DTS service is 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 DTS server IP addresses to a whitelist.

      • If the source or destination database is a self-managed database (the Access Method is not Alibaba Cloud Instance), you must also click Test Connectivity in the CIDR Blocks of DTS Servers dialog box that appears.

    5. Configure the task objects.

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

        Parameter

        Description

        Synchronization Type

        • If you only need to perform a full migration, select both Schema Migration and Full Data Migration.

        • To perform a migration with no downtime, select Schema Migration, Full Data Migration, and Incremental Data Migration.

        Note

        • If you do not select Schema Migration, you must ensure that a database and tables to receive the data exist in the destination database. You can also use the object name mapping feature in the Selected Objects box as needed.

        • If you do not select Incremental Data Migration, do not write new data to the source instance during data migration to ensure data consistency.

        Naming Rules of Additional Columns

        When DTS migrates data to DataHub, it adds extra columns to the destination table. If a name conflict occurs between an additional column and an existing column in the destination table, the data migration will fail. You must select New Rule or Previous Rule based on your business needs.

        Warning

        Before you select a rule for additional columns, you must assess whether name conflicts will occur between the additional columns and existing columns in the destination table. Otherwise, data loss or task failure may occur. For more information about the rules and definitions for additional columns, see Additional column names and definitions.

        Processing Mode for Existing Destination Tables

        • Precheck and Report Errors: Checks whether the destination database contains tables that have the same names as tables in the source database. If no tables with the same name exist, the precheck passes. If tables with the same name exist, an error is reported during the precheck and the data migration task cannot be started.

          Note

          If it is inconvenient to delete or rename the tables with the same name in the destination database, you can change their names in the destination database. For more information, see Map table and column names.

        • Ignore Errors and Proceed: Skips the check for tables with the same name in the destination database.

          Warning

          Selecting Ignore Errors and Proceed can cause data inconsistency and pose risks to your business. For example:

          • If the table schemas are consistent and a record in the destination database has the same primary key value as a record in the source database:

            • During incremental migration, the record from the source database overwrites the record in the destination database.

          • If the table schemas are inconsistent, data initialization might fail, only some columns might be migrated, or the migration might fail.

        Source Objects

        In the Source Objects box, click the objects to migrate, and then click Right arrow to move them to the Selected Objects box.

        Note

        You can select objects to migrate at the table level.

        Selected Objects
        Note

        • If you use the object name mapping feature, the migration of other objects that depend on the renamed object might fail.

        • To filter data by using WHERE conditions, right-click the table to be migrated in the Selected Objects box and specify the filter conditions in the dialog box that appears. For instructions, see Set filter conditions.

        • To select the DML or DDL operations for incremental migration at the database or table level, right-click the migration object and select the desired DML and DDL operations in the dialog box that appears. For a list of supported operations, see SQL operations supported for incremental migration.

        • Right-click a table to be migrated in the Selected Objects box, clear the Sync All Columns check box in the dialog box that appears, and then set the Shardkey (the key used for partitioning).

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

        Parameter

        Description

        Dedicated Cluster for Task Scheduling

        By default, DTS schedules tasks on a shared cluster. You do not need to select one. If you want more stable tasks, you can purchase a dedicated cluster to run DTS migration tasks.

        Set Alerts

        Select whether to set alerts and receive alert notifications based on your business needs.

        • No: Does not set an alert.

        • Yes: Configure alerts by setting an alert threshold and an alert notifications. If a migration fails or the latency exceeds the threshold, the system sends an alert notification.

        Retry Time for Failed Connections

        After the migration task starts, if the connection to the source or destination database fails, DTS reports an error and immediately begins to retry the connection. The default retry duration is 720 minutes. You can customize the retry time to a value from 10 to 1440 minutes. We recommend that you set the duration to more than 30 minutes. If DTS reconnects to the source and destination databases within the specified duration, the migration task automatically resumes. Otherwise, the task fails.

        Note

        • For multiple DTS instances that share the same source or destination, the network retry time is determined by the setting of the last created task.

        • Because you are charged for the task during the connection retry period, we recommend that you customize the retry time based on your business needs, or release the DTS instance as soon as possible after the source and destination database instances are released.

        Retry Time for Other Issues

        After the migration task starts, if a non-connectivity issue, such as a DDL or DML execution exception, occurs in the source or destination database, DTS reports an error and immediately begins to retry the operation. The default retry duration is 10 minutes. You can customize the retry time to a value from 1 to 1440 minutes. We recommend that you set the duration to more than 10 minutes. If the related operations succeed within the specified retry duration, the migration task automatically resumes. Otherwise, the task fails.

        Important

        The value of Retry Time for Other Issues must be less than the value of Retry Time for Failed Connections.

        Enable Throttling for Full Data Migration

        During full migration, DTS consumes read and write resources on the source and destination databases, which may increase the database load. If required, you can enable throttling for the full migration task. You can set Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s) to reduce the load on the destination database.

        Note

        • This configuration item is available only if you select Full Data Migration for Migration Types.

        • You can also adjust the full migration speed after the migration instance is running.

        Enable Throttling for Incremental Data Migration

        If required, you can also choose to set speed limits for the incremental migration task. You can set RPS of Incremental Data Migration and Data migration speed for incremental migration (MB/s) to reduce the load on the destination database.

        Note

        • This configuration item is available only if you select Incremental Data Migration for Migration Types.

        • You can also adjust the incremental migration speed after the migration instance is running.

        Environment Tag

        You can select an environment tag to identify the instance based on your needs. No selection is needed for this example.

        Configure ETL

        Based on your business needs, select whether to configure the ETL feature to process data.

        • Yes: Configures the ETL feature. You must also enter data processing statements in the text box.

        • No: Does not configure the ETL feature.

        Whether to delete SQL operations on heartbeat tables of forward and reverse tasks

        Choose whether DTS writes heartbeat SQL information to the source database while the instance is running.

        • Yes: Does not write heartbeat SQL information to the source database. The DTS instance may display latency.

        • No: Writes heartbeat SQL information to the source database. This may interfere with source database operations like physical backups and cloning.

    6. Save the task and run a precheck.

      • To view the parameters for configuring this instance when you call the API operation, move the pointer over the Next: Save Task Settings and Precheck button and click Preview OpenAPI parameters in the bubble that appears.

      • If you do not need to view or have finished viewing the API parameters, click Next: Save Task Settings and Precheck at the bottom of the page.

      Note

      • Before the migration task starts, DTS performs a precheck. The task starts only after it passes the precheck.

      • If the precheck fails, click View Details next to the failed check item, fix the issue based on the prompt, and then run the precheck again.

      • If a warning is reported during the precheck:

        • For check items that cannot be ignored, click View Details next to the failed item, fix the issue based on the prompt, and then run the precheck again.

        • For check items that can be ignored, you can click Confirm Alert Details, Ignore, OK, and Precheck Again to skip the alert item and run the precheck again. If you choose to ignore a warning, it may cause issues such as data inconsistency and pose risks to your business.

    7. Purchase the instance.

      1. When the Success Rate is 100%, click Next: Purchase Instance.

      2. On the Purchase page, select the link specification for the data migration instance. For more information, see the following table.

        Category

        Parameter

        Description

        New Instance Class

        Resource Group Settings

        Select the resource group to which the instance belongs. The default value is default resource group. For more information, see What is Resource Management?

        Instance Class

        DTS provides migration specifications with different performance levels. The link specification affects the migration speed. You can select a specification based on your business scenario. For more information, see Data migration link specifications.

      3. After the configuration is complete, read and select Data Transmission Service (Pay-as-you-go) Service Terms.

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

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

        Note

        • If the migration task does not include incremental migration, it stops automatically after the full migration is complete. After the task stops, its Status changes to Completed.

        • If the migration task includes incremental migration, it does not stop automatically. The incremental migration task continues to run. While the incremental migration task is running, the Status of the task is Running.