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    Data Transmission Service:Upgrade one-way to two-way synchronization

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    Data Transmission Service:Upgrade one-way to two-way synchronization

    Last Updated:Aug 21, 2026

    This topic describes how to upgrade the synchronization topology of a data synchronization task from one-way to two-way to meet evolving business needs. You can configure a reverse synchronization task for more efficient data interaction.

    Prerequisites

    The one-way synchronization instance that you want to upgrade must meet the following conditions:

    • The instance is a one-way synchronization task, which means its Synchronization Topology is set to One-way Synchronization.

    • The source and destination databases of the instance are of database types and versions that support two-way synchronization. For example, both the source and destination databases are MySQL 8.0.

      For more information, see Supported instances and Synchronization solution overview.

    • The Status of the instance is Running.

    • The account for the destination database has the required permissions.

      For more information, see Permissions for the destination database account.

    • The source or destination database for the instance must not have an SSL-encrypted configured. If an SSL-encrypted is configured, you cannot upgrade the instance to a two-way synchronization task.

    Supported instances

    Source database

    Destination database

    MySQL

    MySQL, PolarDB for MySQL

    PolarDB for MySQL

    MySQL, PolarDB for MySQL

    PostgreSQL

    PostgreSQL, PolarDB for PostgreSQL

    PolarDB for PostgreSQL

    PolarDB for PostgreSQL

    PolarDB (Compatible with Oracle)

    PolarDB (Compatible with Oracle)

    Destination database account permissions

    Destination database type

    Required permissions

    Account setup

    MySQL

    • ApsaraDB RDS for MySQL instance

      A privileged account.

    • Self-managed MySQL database

      The SELECT, REPLICATION CLIENT, REPLICATION SLAVE, and SHOW VIEW permissions, as well as permissions to create databases and tables.

    PolarDB for MySQL

    A privileged account.

    Create and manage a database account

    PostgreSQL

    • ApsaraDB RDS for PostgreSQL instance

      A privileged account that owns the database.

    • Self-managed PostgreSQL database

      Superuser permissions.

    PolarDB for PostgreSQL

    A privileged account that owns the database.

    Create a database account and Manage a database.

    PolarDB (Compatible with Oracle)

    A privileged account that owns the database.

    Create a database account and Manage a database.

    Billing

    • If the billing method is subscription:

      Upgrade fee = (Daily price of the task after the upgrade - Daily price of the task before the upgrade) × Number of remaining days until expiration.

      Note

      The daily price of the upgraded task depends on the remaining subscription period.

      • If the remaining subscription period is less than 300 days, the upgrade fee is based on the monthly price.

      • If the remaining subscription period is 300 days or more, the upgrade fee is based on the yearly price.

    • If the billing method is pay-as-you-go:

      You are charged hourly based on the link specifications of the upgraded task, and the billing rules remain unchanged.

    Note

    For more information about pricing, see Billing overview.

    Precautions

    • You can only upgrade a synchronization task from one-way to two-way. You cannot downgrade a task from two-way to one-way.

    • One-way synchronization tasks between PolarDB-X 2.0 instances cannot be upgraded to two-way synchronization.

    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. Find the target instance.

    3. In the Actions column of the target instance, select More settings > Change to Two-way.

    4. In the dialog box that appears, click OK.

      After the upgrade is complete, a reverse synchronization task with a status of Not configured appears below the original data synchronization task.

    5. Configure the reverse synchronization task based on your business requirements.