All Products
Search

This Product

    Data Transmission Service:Migrate data from PolarDB-X 1.0 to Elasticsearch

    Document Center

    Data Transmission Service:Migrate data from PolarDB-X 1.0 to Elasticsearch

    Last Updated:Feb 13, 2026

    This topic describes how to use Data Transmission Service (DTS) to migrate data from PolarDB-X 1.0 to Elasticsearch.

    Prerequisites

    • You have created a source PolarDB-X 1.0 instance. For more information, see and Create a PolarDB-X 1.0 instance.

      Note

      The storage type of the PolarDB-X 1.0 instance must be RDS for MySQL, such as custom RDS instances or separately purchased RDS instances. PolarDB for MySQL is not supported.

    • You have created a destination Elasticsearch instance. For more information, see Create an Alibaba Cloud Elasticsearch instance.

    • The storage space of the destination Elasticsearch instance must be larger than that of the source PolarDB-X 1.0 instance.

    Important notes

    Type

    Description

    Source database limits

    • The tables to be migrated must have primary keys or UNIQUE constraints, and the fields must be unique. Otherwise, duplicate data may appear in the destination database.

    • If you migrate data at the table level and need to edit the tables, such as mapping column names, a single data migration task supports a maximum of 1,000 tables. If you exceed this limit, an error is reported when you submit the task. In this case, split the tables into multiple batches and configure a separate task for each batch, or configure a task to migrate the entire database.

    • For incremental migration, binary logs:

      • Binary logging must be enabled, and the binlog_row_image parameter must be set to full. Otherwise, an error is reported during the precheck, and the data migration task cannot start.

      • For an incremental migration task, Data Transmission Service (DTS) requires that the binary logs on the source database are retained for at least 24 hours. For a task that includes both full migration and incremental migration, DTS requires that the binary logs on the source database are retained for at least 7 days. After the full migration is complete, you can change the retention period to 24 hours or more. If the retention period is shorter than required, the DTS task may fail because it cannot obtain the binary logs. In extreme cases, data inconsistency or data loss may occur. Issues caused by a binary log retention period that is shorter than the required period are not covered by the Service-Level Agreement (SLA).

    • PolarDB-X 1.0 read-only instances do not support data migration.

    • Limits on operations in the source database:

      • During data migration, do not perform operations such as scale-out, scale-in, hot spot table migration, shard key changes, or DDL operations. Otherwise, the data migration task fails.

        Note

        During the full migration phase, DTS queries the source database. This creates a metadata lock, which may block DDL operations on the source 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 cascade update or delete operations on the source database during data migration, data inconsistency may occur.

      • If you change the network type of the PolarDB-X 1.0 instance during data migration, you must also modify the network connectivity information of the data migration task.

      • If you perform only full data migration, do not write new data to the source instance. Otherwise, data inconsistency occurs between the source and destination. To maintain real-time data consistency, select Schema Migration, Full Data Migration, and Incremental Data Migration.

    • The version of the source PolarDB-X 1.0 instance must be 5.2 or later.

    Other limits

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

    • To add columns to tables in the source database, first modify the corresponding mapping in the Elasticsearch instance. Then run the DDL statement in the source database. Finally, pause and restart the migration task.

    • You cannot migrate data to an index that has a parent-child relationship or a Join field type mapping in the destination instance. Otherwise, the task may become abnormal or data queries in the destination instance may fail.

    • DTS ensures data consistency for incremental migration tasks based on the continuity of XA transactions in the source PolarDB-X 1.0 instance. If the continuity of XA transactions is corrupted, such as in disaster recovery scenarios for the incremental data collection module, uncommitted XA transactions may be lost.

    • Timestamp fields are supported. When a timestamp field in the source database has a value of 0, the corresponding field in the destination database becomes null.

    • Evaluate the performance of both the source and destination databases before migration. Run migration during off-peak business hours. Otherwise, DTS consumes read and write resources on both databases during full migration, increasing database load.

    • DTS attempts to recover failed migration tasks within seven days. Before switching business to the destination instance, end or release the task. Or revoke the write permission of the DTS account on the destination instance using the revoke command. This prevents automatic recovery from overwriting destination data with source data.

    • Development and test specifications of Elasticsearch instances are not supported.

    • 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.

    Other notes

    DTS periodically updates the `dts_health_check`.`ha_health_check` table in the source database to advance the binary log offset.

    Costs

    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

    Note

    Operations that use the UPDATE statement to remove fields are not supported.

    Database account permissions

    Database

    Schema migration

    Full migration

    Incremental migration

    PolarDB Distributed Edition instance

    SELECT

    SELECT

    Read and write permissions on the migration objects.

    Note

    To grant permissions, see Account management.

    Elasticsearch instance

    The database account must have read and write permissions. The default account is elastic.

    Data type mappings

    • Because source databases and Elasticsearch instances support different data types, data types cannot always be mapped directly. During initial schema synchronization, DTS maps data types based on the types that the destination Elasticsearch instance supports. For more information, see Data type mappings for initial schema synchronization.

      Note

      DTS does not set the mapping parameter in the dynamic during schema migration. The behavior of this parameter depends on your Elasticsearch instance settings. If your source data is in JSON format, ensure that the values for the same key have the same data type across all rows in a table. Otherwise, DTS may report synchronization errors. For more information, see dynamic.

    • The following table describes the mappings between Elasticsearch and relational databases.

      Elasticsearch

      Relational database

      Index

      Database

      Type

      Table

      Document

      Row

      Field

      Column

      Mapping

      Database schema

    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.

      Category

      Configuration

      Description

      None

      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 PolarDB-X 1.0.

      Connection Type

      Select Cloud instance.

      Instance Region

      Select the region where the source PolarDB-X 1.0 instance resides.

      Cross Alibaba Cloud account?

      This example uses the same Alibaba Cloud account. Select Not cross-account.

      RDS instance ID

      Select the source PolarDB-X 1.0 instance ID.

      Database Account

      Enter the database account for the source PolarDB-X 1.0 instance. For permission requirements, see Database account permissions.

      Database Password

      Enter the password for this database account.

      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 Elasticsearch.

      Connection Type

      Select Cloud instance.

      Instance Region

      Select the region where the destination Elasticsearch instance resides.

      Type

      Select Cluster or Serverless based on your needs.

      Instance ID

      Select the destination Elasticsearch instance ID.

      Database Account

      You can enter the Logon Name that you specified when you created the Elasticsearch instance. The default account is elastic.

      Database Password

      Enter the password for this database account.

      Encryption

      Select HTTP or HTTPS as needed.

    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.

        Configuration

        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.

        Processing Mode for Existing Destination Tables

        • Precheck and Report Errors: Checks whether tables with the same names exist in the destination database. If no tables with the same names exist, the precheck is passed. If tables with the same names exist, an error is reported during the precheck, and the data migration task does not start.

          Note

          If a table in the destination database has the same name but cannot be easily deleted or renamed, you can change the name of the table in the destination database. For more information, see Object name mapping.

        • Ignore Errors and Proceed: Skips the check for tables with the same names.

          Warning

          Selecting Ignore Errors and Proceed may cause data inconsistency and business risks. 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 full migration, DTS keeps the record in the destination database. The record from the source database is not migrated.

            • During incremental migration, DTS does not keep the record in the destination database. The record from the source database overwrites the record in the destination database.

          • If the table schemas are inconsistent, only some columns of data may be migrated, or the migration may fail. Proceed with caution.

        Index name

        • Select Table name to use the table name as the index name in the destination Elasticsearch instance.

        • Select Database name_Table name to create an index name in the destination Elasticsearch instance by concatenating the database name, underscore (_), and table name.

        Note

        The index name mapping applies to all tables.

        Case Policy for Destination Object Names

        Set case sensitivity for database names, table names, and column names of migrated objects in the destination instance. By default, select DTS default policy. You can also align with the default policies of the source or destination database. For more information, see Case sensitivity policy for destination database object names.

        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

        We recommend that you select tables as the migration objects. If you select an entire database as the migration object, changes, such as adding or deleting tables in that database, are not migrated to the destination database.

        Selected Objects

        • To rename an object that you want to migrate to the destination instance, right-click the object in the Selected Objects section. For more information, see Individual table column mapping.

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

        Note

        • Only underscores (_) are allowed as special characters in index and type names.

        • Using object name mapping may cause migration failures for dependent objects.

        • To filter data using a WHERE clause, right-click the table to migrate in Selected objects, then set the filter condition in the dialog box. For instructions, see Set filter conditions.

        • To select SQL operations at the database or table level, right-click the object to migrate in Selected objects, then select the required SQL operations in the dialog box.

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

        Configuration

        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.

        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

        Select an environment label to identify the instance. This example does not require a label.

        Shard configuration

        Set the number of primary shards and replica shards for the index, based on the maximum shard configuration of the index in the destination Elasticsearch instance.

        String index

        How strings are indexed in the destination Elasticsearch instance.

        • analyzed: Analyze the string first, then index it. You must also select an analyzer. For analyzer types and functions, see Analyzers.

        • not analyzed: Index the raw value without analysis.

        • no: Do not index the string.

        Time zone

        When DTS migrates time-type data (such as DATETIME or TIMESTAMP) to the destination Elasticsearch instance, select the time zone to use.

        Note

        If time-type data in the destination instance should not include time zones, pre-configure the document type (type) for such data in the destination instance.

        DOCID

        By default, DOCID is the table's primary key. If the table has no primary key, DOCID is the ID column auto-generated by Elasticsearch.

        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.

        Monitoring and Alerting

        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.

      3. After completing the preceding configurations, click Next: Configure database and table fields at the bottom of the page to set the _routing strategy and _id value for tables to migrate in the destination Elasticsearch.

        Type

        Description

        Configure _routing?

        Setting _routing routes documents to specific shards in the destination Elasticsearch instance. For more information, see _routing.

        • Select Yes to define a custom column for routing.

        • Select No to route using _id.

        Note

        If the destination Elasticsearch instance is version 7.x, select No.

        _routing column

        Select the column to use for routing.

        Note

        This parameter is required only when Configure _routing? is set to Yes.

        _id value

        Select the column to use as the document ID.

    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.