What causes Masking Policy Error?

The masking policy function references a context function (e.g., CURRENT_ROLE()) but the result is null or unexpected for the executing role. A masking policy was applied to a column whose data type does not match the policy's return type. The masking policy references a secondary role or table that was dropped or renamed. Applying a new masking policy to a Dynamic Table base column triggered a reinitialization that failed. The service account running the query is not in the list of roles that see unmasked data, causing unexpected nulls or tokenized values downstream

How do I fix Masking Policy Error?

Test the masking policy in isolation: `SELECT SYSTEM$POLICY_CONTEXT()` to see the current policy context for your role.. Verify the policy return type matches the column data type: `DESCRIBE MASKING POLICY `.. Check whether the policy references any external tables or secondary roles: `SHOW GRANTS ON MASKING POLICY `.. For Dynamic Table issues: if a base table masking policy changed, recreate the Dynamic Table.. For service accounts: add the service account role to the unmasked role list in the policy body or create a separate policy that returns unmasked values for the service account role.

Medium severitycredentials

Power BI Refresh Error:
Masking Policy Error

What does this error mean?

A Snowflake dynamic data masking policy failed to apply or caused an error during query execution. Queries that reference columns with masking policies may fail or return unexpected results.

Common causes

1The masking policy function references a context function (e.g., CURRENT_ROLE()) but the result is null or unexpected for the executing role
2A masking policy was applied to a column whose data type does not match the policy's return type
3The masking policy references a secondary role or table that was dropped or renamed
4Applying a new masking policy to a Dynamic Table base column triggered a reinitialization that failed
5The service account running the query is not in the list of roles that see unmasked data, causing unexpected nulls or tokenized values downstream

How to fix it

1Test the masking policy in isolation: `SELECT SYSTEM$POLICY_CONTEXT()` to see the current policy context for your role.
2Verify the policy return type matches the column data type: `DESCRIBE MASKING POLICY <policy_name>`.
3Check whether the policy references any external tables or secondary roles: `SHOW GRANTS ON MASKING POLICY <policy_name>`.
4For Dynamic Table issues: if a base table masking policy changed, recreate the Dynamic Table.
5For service accounts: add the service account role to the unmasked role list in the policy body or create a separate policy that returns unmasked values for the service account role.

Frequently asked questions

How do I check which columns have masking policies applied?

Query INFORMATION_SCHEMA: `SELECT * FROM TABLE(INFORMATION_SCHEMA.POLICY_REFERENCES(POLICY_NAME=>'<policy>'))` or `SELECT * FROM INFORMATION_SCHEMA.COLUMNS WHERE MASKING_POLICY_NAME IS NOT NULL`.