Snowflake Low Row Access Policy Mode

The Snowflake low row access policy mode improves query performance in Immuta's Snowflake integration by decreasing the number of Snowflake row access policies Immuta creates and by using table grants to manage user access.

Immuta manages access to Snowflake tables by administering Snowflake row access policies and column masking policies on those tables, allowing users to query them directly in Snowflake while policies are enforced.

Without Snowflake low row access policy mode enabled, row access policies are created and administered by Immuta in the following scenarios:

• Table grants are disabled and a subscription policy that does not automatically subscribe everyone to the data source is applied. Immuta administers Snowflake row access policies to filter out all the rows to restrict access to the entire table when the user doesn't have privileges to query it. However, if table grants are disabled and a subscription policy is applied that grants everyone access to the data source automatically, Immuta does not create a row access policy in Snowflake. See the subscription policies page for details about these policy types.

• Purpose-based policy is applied to a data source. A row access policy filters out all the rows of the table if users aren't acting under the purpose specified in the policy when they query the table.

• Row-level security policy is applied to a data source. A row access policy filters out rows querying users don't have access to.

• User impersonation is enabled. A row access policy is created for every Snowflake table registered in Immuta.

Reducing row access policies

To reduce the number of row access policies Immuta creates and improve query performance, the Snowflake low row access policy mode requires you to

• Enable table grants.
• Disable user impersonation. User impersonation diminishes the performance of interactive queries because of the number of row access policies Immuta creates when it's enabled.

Requirements

• Snowflake integration with governance features enabled
• Snowflake table grants enabled

Limitations and considerations

• Project workspaces are not compatible with this feature.
• Impersonation is not supported when the Snowflake low row access policy mode is enabled.
• When a project member acts under a project's purposes, any matching purpose exceptions on tables will be honored, even if those tables exist outside the project. Project managers cannot assume approving a purpose means that the purposes of that project are limited to the tables in the project.
• Project owners cannot limit masked joins to a single project. Turning masked joins on in a single project in Immuta enables masked joins across all of a subscriber's data sources, regardless of which projects the data sources belong to.