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    Data Transmission Service:Synchronize data from a PolarDB-X 2.0 instance to an AnalyticDB for MySQL V3.0 cluster

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    Data Transmission Service:Synchronize data from a PolarDB-X 2.0 instance to an AnalyticDB for MySQL V3.0 cluster

    Last Updated:Sep 16, 2026

    This topic describes how to use Data Transmission Service (DTS) to synchronize data from a PolarDB-X 2.0 instance to an AnalyticDB for MySQL V3.0 cluster, so that you can quickly build systems such as internal business intelligence (BI), interactive query, and real-time reporting.

    Prerequisites

    • A source PolarDB-X 2.0 instance is created.

    • 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 storage space used by the source PolarDB-X 2.0 instance.

    Precautions

    Note

    • During database and table schema synchronization, DTS does not synchronize foreign keys from the source database to the destination database.

    • Throughout both full and incremental synchronization, DTS temporarily disables constraint checks and foreign key cascading operations at the session level. If cascading updates or deletions occur in the source database while the task is running, data inconsistency may result.

    • DTS does not support synchronizing materialized views to the destination AnalyticDB MySQL instance during schema synchronization; if materialized views are required, you must create them manually on the destination instance after synchronization is complete.

    Type

    Description

    Source database limitations

    • Synchronized tables must have a primary key or a unique constraint. Otherwise, duplicate data may occur in the destination database.

    • DTS does not support Enterprise Edition PolarDB-X 2.0 read-only instances as the source database.

    • If you synchronize tables individually and perform edits, such as column name mapping, a single data synchronization task supports a maximum of 5,000 tables. To synchronize more than 5,000 tables, split them across multiple tasks or configure the task to synchronize the entire database. Otherwise, a request error may occur after you submit the task.

    • Binary log requirements:

      • You must enable the binary log feature in the PolarDB-X 2.0 console and set the binlog_row_image parameter to full. For more information, see Parameter settings. Otherwise, the precheck fails and the data synchronization task cannot start.

      • For incremental data synchronization, you must retain the source database's binary logs for over 24 hours. For tasks that combine full and incremental synchronization, the retention period must be at least 7 days. After the full data synchronization is complete, you can reduce the retention period to 24 hours. The DTS SLA does not cover issues caused by an insufficient binary log retention period.

    • If a table name in the source PolarDB-X 2.0 instance contains uppercase letters, DTS supports only schema synchronization for that table.

    • DTS does not support synchronizing table groups (TABLEGROUP) or databases and tables that have the Locality attribute.

    • DTS does not support synchronizing tables whose names are reserved keywords, such as select.

    • DTS cannot synchronize partitions of databases in DRDS mode on a PolarDB-X 2.0 instance.

    • Do not run DDL operations that change database or table schemas during schema synchronization or full synchronization. Otherwise, the synchronization task fails.

      Note

      During full synchronization, DTS queries the source database. This creates metadata locks that may block DDL operations on the source database.

    • During the operation of a DTS synchronization task, changing the type of a broadcast table in the source PolarDB-X 2.0 instance (for example, changing a broadcast table to a regular table or a sharded table) is not supported. To change the table type, stop the synchronization task first, and then reconfigure the synchronization task after the change is complete.

    Other limitations

    • DTS does not synchronize prefix indexes. If the source database contains prefix indexes, the data synchronization task may fail.

    • The destination database must contain a custom primary key. Or, in the Configurations for Databases, Tables, and Columns step, configure a Primary Key Column. Otherwise, synchronization may fail.

    • Due to the limitations of AnalyticDB for MySQL, the DTS task may be delayed or fail if the node disk usage in the destination AnalyticDB for MySQL cluster exceeds 80%. Before you start the task, estimate the required disk space based on the objects to be synchronized and ensure the destination cluster has sufficient storage.

    • If the destination AnalyticDB for MySQL 3.0 cluster is backing up while the DTS task runs, the task fails.

    • Evaluate the performance of your source and destination databases before starting data synchronization. Perform the synchronization during off-peak hours, as initial full data synchronization consumes significant resources and increases the database load.

    • Initial full data synchronization runs concurrent INSERT operations, which can cause table fragmentation in the destination database. Consequently, the destination instance may occupy more tablespace than the source instance after synchronization.

    • Do not use tools like pt-online-schema-change to perform online DDL operations on the objects being synchronized in the source database. Otherwise, the synchronization task fails.

    • During synchronization, do not use non-DTS tools to write data to the destination database. Otherwise, data inconsistency may occur between the source and destination databases. For example, if tools other than DTS write data to the destination database and you then use DMS to perform online DDL changes, data loss may occur in the destination database.

    • If a DDL statement fails to execute on the destination database, the DTS task continues to run. You must check the task logs to find the failed DDL statement. For more information, see View task logs.

    • 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.

    • When the destination database is an AnalyticDB for MySQL instance, DTS supports writing only the data types supported by the destination database, including basic data types and complex data types such as ARRAY, MAP, and JSON. DTS does not support other types such as MULTIVALUE.

    Other precautions

    DTS periodically updates the dts_health_check.ha_health_check table in the source database to advance the binlog position.

    Billing

    Synchronization type

    Pricing

    Schema synchronization and full data synchronization

    Free of charge.

    Incremental data synchronization

    Charged. For more information, see Billing overview.

    Supported synchronization topologies

    • One-way one-to-one synchronization

    • One-way one-to-many synchronization

    • One-way cascade synchronization

    • One-way many-to-one synchronization

    For more information, see Introduction to data synchronization topologies.

    SQL operations that can be synchronized

    Operation type

    SQL statement

    DML

    INSERT, UPDATE, and DELETE

    Note

    When data is written to the AnalyticDB for MySQL cluster, the UPDATE statement is automatically converted to the REPLACE INTO statement.

    DDL

    CREATE TABLE, DROP TABLE, RENAME TABLE, TRUNCATE TABLE, ADD COLUMN, and DROP COLUMN

    Procedure

    1. Go to the data synchronization task list page in the destination region. You can do this in one of two ways.

      DTS console

      1. Log on to the DTS console.

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

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

      DMS console

      Note

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

      1. Log on to the DMS console.

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

      3. To the right of Data Synchronization Tasks, select the region of the synchronization instance.

    2. Click Create Task to open 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

      • Select the registered database instance with DTS from the drop-down list. The database information below is automatically configured.

        Note

        In the DMS console, this configuration item is Select a DMS database instance.

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

      Database Type

      Select PolarDB-X 2.0.

      Connection Type

      Select Alibaba Cloud Instance.

      Instance Region

      Select the region where the source PolarDB-X 2.0 instance resides.

      Replicate Data Across Alibaba Cloud Accounts

      In this example, the source and destination instances belong to the same Alibaba Cloud account. Select No.

      Instance ID

      Select the ID of the source PolarDB-X 2.0 instance.

      Database Account

      Enter the database account of the source PolarDB-X 2.0 instance. The account must have the REPLICATION SLAVE and REPLICATION CLIENT permissions and the SELECT permission on the objects to be synchronized.

      Note

      For information on how to grant permissions, see Account permission issues during data synchronization.

      Database Password

      Enter the password for the specified database account.

      Destination Database

      Select Existing Connection

      • Select the registered database instance with DTS from the drop-down list. The database information below is automatically configured.

        Note

        In the DMS console, this configuration item is Select a DMS database instance.

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

      Database Type

      Select AnalyticDB for MySQL 3.0.

      Connection Type

      Select Alibaba Cloud Instance.

      Instance Region

      Select the region where the destination AnalyticDB for MySQL V3.0 cluster resides.

      Replicate Data Across Alibaba Cloud Accounts

      In this example, the source and destination instances belong to the same Alibaba Cloud account. Select No.

      Instance ID

      Select the ID of the destination AnalyticDB for MySQL V3.0 cluster.

      Database Account

      Enter the database account of the destination AnalyticDB for MySQL V3.0 cluster. The account must have read and write permissions.

      Database Password

      Enter the password for the specified database account.

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

      Note

      Ensure that the IP address blocks of the DTS service are added to the security settings of the source and destination databases, either automatically or manually, to allow access from DTS servers. For more information, see Add the IP address whitelist of DTS servers.

    5. Configure the task objects.

      1. On the Configure Objects page, specify the objects to synchronize.

        Parameter

        Description

        Synchronization Type

        DTS always selects Incremental Data Synchronization. By default, you must also select Schema Synchronization and Full Data Synchronization. After the precheck, DTS initializes the destination cluster with the full data of the selected source objects, which serves as the baseline for subsequent incremental synchronization.

        Note

        If Full Data Synchronization is selected, you can synchronize the schema and data of the table that is created by executing the CREATE TABLE statement to the destination database.

        Processing Mode for Existing Destination Tables

        • Precheck and Report Errors: Checks for tables with the same names in the destination database. If any tables with the same names are found, an error is reported during the precheck and the data synchronization task does not start. Otherwise, the precheck is successful.

          Note

          If you cannot delete or rename the table with the same name in the destination database, you can map it to a different name in the destination. For more information, see Object name mapping.

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

          Warning

          Selecting Ignore Errors and Proceed may cause data inconsistency and put your business at risk. For example:

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

            • During full data synchronization, DTS retains the destination record and skips the source record.

            • During incremental synchronization, DTS overwrites the destination record with the source record.

          • If the table schemas are inconsistent, data initialization may fail. This can result in only partial data synchronization or a complete synchronization failure. Use with caution.

        Table Merging

        • Select Yes: In online transactional processing (TP) scenarios, sharding is often used to improve the response speed of business tables. In online analytical processing (OLAP) scenarios, a single table in the destination database can store large volumes of data, which simplifies single-table queries. In such scenarios, you can use the DTS table merging feature to synchronize multiple tables with the same schema (sharded tables) from the source database to a single table in the destination database. For details on this operation, see Enable table merging.

          Note

          • After you select multiple tables from the source database, you must use the object name mapping feature to change their names to the same table name in the destination database. For more information about the object name mapping feature, see Object name mapping.

          • DTS adds a __dts_data_source column of the TEXT type to the destination table to store the data source. The column value is written in the DTS instance ID:database name:schema name:table name format to distinguish the source of the table, for example, dts********:dtstestdata:testschema:customer1.

          • The table merging feature applies at the task level, not the table level. To merge only some tables, you must create a separate data synchronization task for them.

          Warning

          Do not perform DDL operations that change the database or table schema in the source database. Otherwise, data inconsistency or task failure may occur.

        • No: This is the default option.

        Source Objects

        In the Source Objects box, click the objects, and then click 向右 to move them to the Selected Objects box.

        Note

        • You can select columns, tables, or databases as the objects to synchronize. If you select tables or columns, DTS does not synchronize other objects such as views, triggers, or stored procedures to the destination database.

        • If you select a database as the object to synchronize, DTS applies the following default rules:

          • If the source table has a primary key (single-column or composite), the primary key columns are used as the distribution keys.

          • If the source table does not have a primary key, an auto-increment primary key column is generated in the destination table. This may cause data inconsistency between the source and destination databases.

        Selected Objects

        • To rename a single object in the destination instance, right-click the object in the Selected Objects box. For more information, see Map a single object name.

        • To rename multiple objects in bulk, click Batch Edit in the upper-right corner of the Selected Objects box. For more information, see Map multiple object names in bulk.

        Note

        • To select SQL operations to be synchronized at the database or table level, right-click the objects to be synchronized in the Selected Objects section, and select the required SQL operations in the dialog box that appears.

        • To filter data by using a WHERE condition, right-click a table to be synchronized in the Selected Objects section, and configure filter conditions in the dialog box that appears. For more information, see Filter task data with an SQL condition.

      2. Click Next: Advanced Settings.

        Parameter

        Description

        Dedicated Cluster for Task Scheduling

        By default, DTS uses a shared cluster for tasks, so you do not need to make a selection. For greater task stability, you can purchase a dedicated cluster to run the DTS synchronization task. For more information, see What is a DTS dedicated cluster?.

        Retry Time for Failed Connections

        If the connection to the source or destination database fails after the synchronization task starts, 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 1,440 minutes. We recommend a duration of 30 minutes or more. If the connection is restored within this period, the task resumes automatically. Otherwise, the task fails.

        Note

        • If multiple DTS instances (e.g., Instance A and B) share a source or destination, DTS uses the shortest configured retry duration (e.g., 30 minutes for A, 60 for B, so 30 minutes is used) for all instances.

        • DTS charges for task runtime during connection retries. Set a custom duration based on your business needs, or release the DTS instance promptly after you release the source/destination instances.

        Retry Time for Other Issues

        If a non-connection issue (e.g., a DDL or DML execution error) occurs, DTS reports an error and immediately retries the operation. The default retry duration is 10 minutes. You can also customize the retry time to a value from 1 to 1,440 minutes. We recommend a duration of 10 minutes or more. If the related operations succeed within the set retry time, the synchronization task automatically resumes. Otherwise, the task fails.

        Important

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

        Enable Throttling for Full Data Synchronization

        During full data synchronization, DTS consumes read and write resources from the source and destination databases, which can increase their load. To mitigate pressure on the destination database, you can limit the migration rate by setting Queries per second (QPS) to the source database, RPS of Full Data Migration, and Data migration speed for full migration (MB/s).

        Note

        Enable Throttling for Incremental Data Synchronization

        You can also limit the incremental synchronization rate to reduce pressure on the destination database by setting RPS of Incremental Data Synchronization and Data synchronization speed for incremental synchronization (MB/s).

        Environment Tag

        Select an environment tag to identify the instance based on your business needs. No selection is required for this example.

        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.

        Configure ETL

        Choose whether to enable the extract, transform, and load (ETL) feature. For more information, see What is ETL? Valid values:

        Monitoring and Alerting

        Choose whether to set up alerts. If the synchronization fails or the latency exceeds the specified threshold, DTS sends a notification to the alert contacts.

      3. Optional: After you complete the configuration, click Next: Configure Database and Table Fields to set the Type, Primary Key Column, Distribution Key, and partition key information (Partition Key, Partitioning Rules, and Partition Lifecycle) for the tables to sync in the destination database.

        Note

        • This step is available only if you select the Schema Synchronization checkbox for Synchronization Types during task object configuration. You can set Definition Status to All to make modifications.

        • You can use the Primary Key Column to specify a composite primary key that consists of multiple columns. You must then select one or more columns from the Primary Key Column to serve as the Distribution Key and Partition Key. For more information, see CREATE TABLE.

    6. Save the task and perform a precheck.

      • To view the parameters for configuring this instance via an API operation, hover over the Next: Save Task Settings and Precheck button and click Preview OpenAPI parameters in the tooltip.

      • If you have finished viewing the API parameters, click Next: Save Task Settings and Precheck at the bottom of the page.

      Note

      • Before a synchronization task starts, DTS performs a precheck. You can start the task only if the precheck passes.

      • If the precheck fails, click View Details next to the failed item, fix the issue as prompted, and then rerun the precheck.

      • If the precheck generates warnings:

        • For non-ignorable warning, click View Details next to the item, fix the issue as prompted, and run the precheck again.

        • For ignorable warnings, you can bypass them by clicking Confirm Alert Details, then Ignore, and then OK. Finally, click Precheck Again to skip the warning and run the precheck again. Ignoring precheck warnings may lead to data inconsistencies and other business risks. Proceed with caution.

    7. Purchase the instance.

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

      2. On the Purchase page, select the billing method and link specifications for the data synchronization instance. For more information, see the following table.

        Category

        Parameter

        Description

        New Instance Class

        Billing Method

        • Subscription: You pay upfront for a specific duration. This is cost-effective for long-term, continuous tasks.

        • Pay-as-you-go: You are billed hourly for actual usage. This is ideal for short-term or test tasks, as you can release the instance at any time to save costs.

        Resource Group Settings

        The resource group to which the instance belongs. The default is default resource group. For more information, see What is resource management?.

        Instance Class

        DTS offers synchronization specifications at different performance levels that affect the synchronization rate. Select a specification based on your business requirements. For more information, see Data synchronization link specifications.

        Subscription Duration

        In subscription mode, select the duration and quantity of the instance. Monthly options range from 1 to 9 months. Yearly options include 1, 2, 3, or 5 years.

        Note

        This option appears only when the billing method is Subscription.

      3. Read and select the checkbox for Data Transmission Service (Pay-as-you-go) Service Terms.

      4. Click Buy and Start, and then click OK in the OK dialog box.

        You can monitor the task progress on the data synchronization page.