View data verification details

Prerequisites

A data verification task is created and configured. For more information, see Configure data verification.

Usage notes

• For a data verification task that is configured in a data synchronization or migration instance, you can view its details on the instance details page or the Data Verification page. For a standalone data verification task, you can view its details only on the Data Verification page.

• We recommend that you view the Check Details for full data verification and schema verification tasks only when their status is Complete. For incremental data verification tasks, view the Check Details only when the Current Offset is after the time of the incremental data change.

• An incremental data verification task merges multiple changes made to the same data record within a specific period and then performs a consistency check. Therefore, the number of records displayed for the task may be smaller than the actual number of incremental changes.

• Inconsistent data found by a verification task is retained for 30 days by default. Review and handle any inconsistencies in a timely manner.

• If a full data verification task detects inconsistent data, you must manually correct the data and then run a manual verification or re-run the full verification task to confirm data consistency.

• If an incremental data verification task detects inconsistent data, DTS automatically re-verifies the inconsistent data approximately every 10 minutes. This interval may increase if there is a large amount of inconsistent data.

• You are charged for incremental validation tasks even when they are paused.

View details on the Data Verification page

1. Go to the data verification task list page. Choose one of the following methods.

   DTS console (quick)

   1. Go to the Data Verification page.

   2. Optional: In the upper-left corner of the page, select the region of the verification instance.

   DTS console (standard)

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

   2. In the left-side navigation pane, click Data Verification.

   3. Optional: In the upper-left corner of the page, select the region of the verification instance.

   DMS console

   Note

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

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

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

   3. Optional: To the right of Verification Task, select the region of the verification instance.

2. Click the ID of the target instance to open its details page.

3. Optional: In the left-side navigation pane, click Task Management.

4. In the Progress section, click Full Data Verification, Incremental Data Verification, or Schema Verification to view the verification details.

   • Basic Information

     The Basic Information tab displays information about the data verification task, such as its start time, verification time rule, status, progress, and error messages. The information displayed may vary based on your configurations.

     After the verification task starts, you can Restart, Pause, Stopped, or Delete as needed. For more information, see What to do next.

     Important

     The Status on the Basic Information tab shows the status of the data verification task. You can view the verification results on the Check Details tab.

   • Check Details

     On the Check Details tab, you can filter and view the results of the verification task, such as the names of the source and destination databases and tables, verification status, and verification time.

     Note

     • The results on the Check Details tab are sorted in descending order by the Number of Inconsistent Records.

     • You can download a revised SQL statement only for a full data verification task. For tasks that were started before 14:04:52 (UTC+8) on November 20, 2023, you must run the verification again to enable this feature.

     • The Total Number of Records is an estimated value, while the Number of records completed by verification is the actual count of verified records. Therefore, the Number of records completed by verification may be higher than the Total Number of Records.

     • If the Number of Inconsistent Records is 0, the data is consistent between the source and destination databases. In this case, you do not need to view or download the verification report because it contains no data.

     • If the Number of Inconsistent Records is not 0, data or schema inconsistencies exist between the source and destination databases. In the Actions column, you can click View Report, Download Report, or Download Revised SQL Statements as needed. You can use the downloaded report and revised SQL statement to manually fix the inconsistencies.

       Important

       Use caution when executing DELETE statements from a revised SQL statement.

View details in synchronization or migration instances

1. Go to the task list page for data synchronization or data migration. You can use one of the following two methods.

   From the DTS console

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

   2. In the left-side navigation pane, click Data Synchronization or Data Migration.

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

   From the DMS console

   Note

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

   1. Log in to the Data Management Service (DMS) console.

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

   3. Optional: To the right of Data Synchronization Tasks or Data Migration Tasks, select the region of the synchronization or migration instance.

2. Click the ID of the target synchronization or migration instance to open its details page.

3. Optional: In the left-side navigation pane, click Task Management.

4. To the right of Progress, clear the Hide Completed Modules checkbox.

5. In the Progress section, click Full Data Verification, Incremental Data Verification, or Schema Verification to view the verification details.

   • Basic Information

     The Basic Information tab displays information about the data verification task, such as its start time, verification time rule, status, progress, and error messages. The information displayed may vary based on your configurations.

     After the verification task starts, you can Restart, Pause, Stopped, or Delete as needed. For more information, see What to do next.

     Important

     The Status on the Basic Information tab shows the status of the data verification task. You can view the verification results on the Check Details tab.

   • Check Details

     On the Check Details tab, you can filter and view the results of the verification task, such as the names of the source and destination databases and tables, verification status, and verification time.

     Note

     • The results on the Check Details tab are sorted in descending order by the Number of Inconsistent Records.

     • You can download a revised SQL statement only for a full data verification task. For tasks that were started before 14:04:52 (UTC+8) on November 20, 2023, you must run the verification again to enable this feature.

     • The Total Number of Records is an estimated value, while the Number of records completed by verification is the actual count of verified records. Therefore, the Number of records completed by verification may be higher than the Total Number of Records.

     • If the Number of Inconsistent Records is 0, the data is consistent between the source and destination databases. In this case, you do not need to view or download the verification report because it contains no data.

     • If the Number of Inconsistent Records is not 0, data or schema inconsistencies exist between the source and destination databases. In the Actions column, you can click View Report, Download Report, or Download Revised SQL Statements as needed. You can use the downloaded report and revised SQL statement to manually fix the inconsistencies.

       Important

       Use caution when executing DELETE statements from a revised SQL statement.

What to do next

If you need to re-verify data differences between the source and destination instances, for example, after modifying data in the destination instance based on a verification report, you can manage the verification task in the Progress section.

1. Go to the Task Management page of the target instance.

2. To the right of Progress, clear the Hide Completed Modules checkbox.

3. Click the Full Data Verification or Incremental Data Verification module.

4. Optional: Click the Basic Information tab.

5. Manage the verification task.

   • Pause a verification task

     Important

     • You can pause a verification task only while it is running.

     • Resumable verification is not supported for a full data verification task after it is paused.

     Click Pause to the right of Actions, and click OK in the Note dialog box that appears. After the verification task is paused, its Status changes to Pausing.

   • Restart a verification task

     Note

     • You can restart the verification task only when its Status is Pausing or Completed.

     • When a full data verification task is restarted, it re-verifies all existing data in the source and destination databases.

     To the right of Actions, click Restart. In the Note dialog box that appears, click OK.

   • Stop a verification task

     Note

     Only incremental data verification tasks support the stop operation. After a task is stopped, its Status changes to Completed.

     To the right of Actions, click Stopped. In the Note dialog box that appears, click OK.

   • Delete a verification task

     Important

     A deleted verification task cannot be recovered. You can only create a new one.

     To the right of Actions, click Delete. In the Note dialog box that appears, click OK.

API reference

FAQ

• How do I recreate a full or incremental data verification task?

  You can use one of the following methods:

  • On the Data Verification page, create a standalone verification task.

    Note

    You cannot create an incremental data verification task on this page.

  • Go to the Full Data Verification or Incremental Data Verification module of the target instance. On the Basic Information tab, click Delete, and then click Create Verification Task at the top of the page.

    Note

    DTS does not support data verification for instances whose Status is Completed.

• Why does the verification status show "Failed"?

  The verification may fail for any of the following reasons:

  • The table to be verified has no primary key or unique index, and it contains more than 10,000 rows. In this case, DTS does not perform data verification.

  • The data to be verified has neither a primary key constraint nor a unique constraint. In this case, DTS does not perform incremental data verification.

  • Verifying materialized views is not supported.

  • The number of different rows in a single table between the source and destination databases exceeds 100,000. This can happen if data synchronization is incomplete or if conflicts exist.

  • The connection to the source or destination database is unstable during the verification task. This can be caused by network interruptions or changes in account permissions.

  Go to the verification details page to find the specific reason for the failure and troubleshoot the issue. For more information, see Usage notes.

• Why does a full or incremental data verification task not start?

  The reason depends on whether the instance includes an incremental write module (incremental synchronization or migration):

  • Without an incremental write module:

    Full data verification starts after the full data write is complete.

  • With an incremental write module:

    Note

    Full and incremental data verification tasks are independent and do not affect each other.

    • If the incremental task is a single task without subtasks, both full and incremental data verification start when the incremental write module first achieves zero latency.

    • If the incremental task includes multiple subtasks, such as in a migration between MongoDB instances, both full and incremental data verification start when the latency of all subtasks drops below 2 seconds.

• Why are the results of an incremental data verification task always empty?

  An incremental data verification task records only information about databases and tables with inconsistent data. If incremental data in the source database is synchronized or migrated to the destination database and the incremental verification finds no inconsistencies, the results list is empty.

• Why is the current offset in the incremental verification module not updated?

  The Current Offset in the incremental verification module indicates the timestamp of the last incremental verification. If there is no new incremental data in the source database, the Current Offset is not updated or may show no timestamp.

• Why is inconsistent data not detected by the incremental data verification task even when incremental data is written to the destination database?

  An incremental data verification task uses the source database as the baseline to check for consistency with the destination database. Inconsistent data is detected only if data changes in the source database are not written to the destination database, or if the written data does not match the data in the source database.