Get error in DMS Validation

The error you're encountering in AWS DMS validation, "ERROR: numeric field overflow; Error while executing the query", is likely related to a mismatch in data types or precision between your source and target databases. This issue commonly occurs when migrating numerical data, especially when dealing with columns defined as numeric data types without specified precision or scale.

To address this issue and ensure a complete migration of all tables and rows, you can try the following solutions:

1. Use the Extra Connection Attribute (ECA) "MapUnboundedNumericAsString=true" for both source and target endpoints. This will map unbounded numeric data as a string type during migration, which can help avoid truncation issues.

2. Review the data types of the affected columns in both the source and target databases. Ensure that the target database can accommodate the full range of values from the source, including any potential decimal places.

3. If the data truncation is acceptable for your business needs, you can set up override validation rules with custom functions to handle the discrepancy.

4. Consider adjusting the precision and scale of the numeric columns in the target database to match or exceed those in the source database.

5. If the issue persists, you may need to use table mapping rules to transform the data during migration, ensuring that it fits within the constraints of the target database.

It's important to note that while this error is occurring during validation, it doesn't necessarily mean that data is not being migrated. However, it does indicate that there may be discrepancies between the source and target data due to the overflow issue. To ensure data integrity, it's crucial to resolve this error and revalidate the affected tables.

If the problem continues after trying these solutions, you may need to examine the specific data in the problematic table and consider custom handling for those particular numeric fields.
Sources
Optimize data validation using AWS DMS validation-only tasks | AWS Database Blog
"Column specified more than once" error on target even though it is specified only once in source | AWS re:Post