Why did my AWS DMS task validation fail, or why isn't the validation progressing?

Short description

When you enable validation for an AWS DMS task, you can review statistics at the table level and configure data validation settings. You can view the data validation information using the AWS DMS console, the AWS Command Line Interface (AWS CLI), or the AWS DMS API.

Resolution

Note: If you receive errors when running AWS CLI commands, make sure that you’re using the most recent version of the AWS CLI.

1.    To view the data validation report, open the AWS DMS console.

2.    Choose Database migration tasks from the navigation pane.

3.    Choose the name of your task.

4.    From the Table statistics section, review the Validation state. Or you can run describe-table-statistics to review the data validation report in JSON format:

aws dms  describe-table-statistics --replication-task-arn arn:aws:dms:us-east-1:45454545454:rep:XXXXXXXXXXXXXXXXXX

If the validation state is Mismatched records, then query the table awsdms_validation_failures_v1 that is created by AWS DMS on the target database:

select * from awsdms_validation_failures_v1 where TASK_NAME = 'XXXXXXXXXXXXXXXXXX';

Note: The value of TASK_NAME is the external resource ID of the task, which is the last value in the task Amazon Resource Name (ARN).

After you have the primary key of the failed record, query the source and target endpoints to see what part of the record doesn't match.

If the validation state is Pending records, then configure the ThreadCount parameter for task validation settings to improve the validation performance. For more information, see Data validation task settings.

For other validation states, see replication task statistics. You can monitor the progress of the validation using CloudWatch metrics.

Related information

Troubleshooting for AWS DMS validation

Limitations for AWS DMS validation