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Data Transmission Service:Switch the direction of a two-way synchronization instance

Last Updated:Mar 28, 2026

In a two-way synchronization instance, DDL operations are synchronized only in the forward task — not the reverse task. To synchronize DDL operations from what is currently the reverse task, switch the direction of the instance. This promotes the reverse task to forward, so you can apply DDL operations and keep both databases consistent.

Prerequisites

Before you begin, ensure that you have:

Limits

  • Distributed two-way synchronization instances do not support direction switching.

  • If data changes in the source or destination database while the switch is in progress, data inconsistency may occur.

  • After switching, the directions and positions of the original forward and reverse tasks are interchanged.

Important

DDL operations are synchronized to the destination database only in the current forward task. After you switch the direction, the new forward task (originally the reverse task) handles DDL synchronization. To synchronize DDL operations in the other direction again, switch the direction a second time before applying those DDL operations.

Switch the direction

  1. Go to the Data Synchronization Tasks page. Log on to the Data Management (DMS) console. In the top navigation bar, click Data + AI. In the left-side navigation pane, choose DTS (DTS) > Data Synchronization.

    Note

    You can also go directly to the Data Synchronization Tasks page of the new DTS console. Console navigation may vary based on your DMS mode and layout. For details, see Simple mode and Customize the layout and style of the DMS console.

  2. In the upper-left corner of the page, select the region where the synchronization instance resides.

  3. Find the two-way synchronization instance, click the ... icon, and select Switch Direction.

  4. In the confirmation dialog, click OK.

After the forward and reverse tasks enter the Running state, the direction of the two-way synchronization instance is switched.