POST_START

Investigating an Authorization Failure After a Table Rename

I recently encountered an issue where a user was unable to access a table after it was renamed in the production environment. The user reported an authorization failure when trying to query the table, but the table itself was visible in the metadata. I needed to investigate why the user’s access was being denied despite the table being present.

My first step was to check the tables in the production.sales schema to confirm the current state of the table. I ran the following SQL command:

SHOW TABLES IN production.sales;

I saw a representative result like this:

database	tableName	isTemporary
sales	customers	false
sales	orders	false

The table customers was indeed present, which confirmed that the rename had completed successfully. However, the user was still unable to access the table. I needed to look deeper into the access controls.

Next, I checked the grants assigned to the production.sales schema to see what permissions were in place for the user. I executed the following command:

SHOW GRANTS ON SCHEMA production.sales;

I saw a representative result like this:

principal	actionType	objectType
data_analysts	USE SCHEMA	SCHEMA
data_engineers	CREATE TABLE	SCHEMA

This showed that the data_analysts group had the USE SCHEMA permission, which allows them to access objects within the schema. However, the data_analysts group didn’t have the SELECT or USE TABLE permissions on the table itself. This indicated that the user might not have the necessary access to the table, even though they could see it in the schema.

To get more insight, I checked the access audit logs for any recent activity related to the table. I ran the following query:

SELECT * FROM system.access.audit WHERE request_params LIKE '%ALTER TABLE%' ORDER BY event_time DESC;

I saw a representative result like this:

event_time	user_identity	action_name	request_params
2026-09-11 14:32:10	analyst@demo.com	commandSubmit	{table: production.sales.customers}
2026-09-11 14:31:55	engineer@demo.com	getTable	{table: production.sales.customers}

This showed that the data_analysts user had attempted to access the table, but the table wasn’t visible to them. The audit log also indicated that the table had been altered recently, which might have triggered a change in access controls.

I realized that the user was likely missing the SELECT permission on the table itself. While they had access to the schema, the table-level permissions were not sufficient for them to query the data. I verified that the table was indeed renamed and that the old name was no longer accessible, which further confirmed that the issue was not with the table’s existence but with the user’s permissions.

By following these steps, I was able to trace the authorization failure back to a lack of table-level access. This experience reinforced the importance of checking both schema and table-level permissions when troubleshooting access issues in Unity Catalog.