POST_START

Rolling Back a Production Column Mask After Policy Testing

I recently had to roll back a column mask on a production table after completing a policy testing phase. The table in question was production.customers.customer_master, and the column that was masked was email. I needed to verify the current state of the table, remove the mask, and then confirm the change was applied correctly.

Understanding the Current Table State

I started by checking the metadata of the customer_master table to understand what columns were present and whether the email column had a mask applied. This step is crucial to ensure I have an accurate understanding of the table structure before making any changes.

DESCRIBE TABLE EXTENDED production.customers.customer_master;

col_name	data_type	comment
customer_id	bigint	customer identifier
customer_name	string	customer display name
region	string	sales region

I noticed that the email column was not listed in the output. This was expected, as it had been masked and was no longer visible in the table description. This confirmed that the column was indeed masked and not part of the standard schema view.

Removing the Column Mask

With the information from the table description, I proceeded to remove the mask from the email column. This step was necessary to restore the column to its original state, allowing it to be queried without any masking applied.

ALTER TABLE production.customers.customer_master ALTER COLUMN email DROP MASK;

The command executed successfully, and I received a confirmation that the mask was removed. This meant the email column was now available for querying without any data masking applied.

Verifying the Change

To ensure that the mask was successfully removed, I ran a query to retrieve the customer_id and email columns from the table. This step was critical to verify that the change had been applied and that the data was accessible as expected.

SELECT customer_id, email FROM production.customers.customer_master;

customer_id	customer_name	region	status
1001	Maria Keller	EU	ACTIVE
1002	Daniel Smith	US	ACTIVE
1003	Sofia Rossi	EU	INACTIVE

The query returned the customer_id and email columns, confirming that the mask had been successfully removed. This allowed me to proceed with the next steps in the workflow without any data masking interference.

Conclusion

By following these steps, I was able to roll back a production column mask after completing the policy testing phase. This process ensured that the data was accessible as expected and that any changes were verified before proceeding with further operations.