Row-level Security (RLS) is a security feature that allows organizations to restrict access to specific rows of data in a database based on user roles, permissions, or other criteria.
Row-level security complements standard SQL privileges (GRANT
/REVOKE
) by allowing administrators to define policies that determine precisely which rows users can view or modify within a specific table.
Use cases
Use cases for row-level security include:
Restricting access to sensitive data for compliance
In industries like finance or healthcare, organizations are required to ensure that only authorized users access sensitive data. Row-level security (RLS) addresses this requirement directly within the database.
For example, RLS allows a financial institution to restrict access to customer records based on roles or departments. In healthcare, RLS can be used to enforce policies ensuring patient records are visible only to the medical staff involved in their care.
RLS embeds access control logic directly into the database and eliminates the need for manual filtering in application code. This centralized enforcement prevents inconsistencies, reduces security attack surface, and simplifies compliance with data access regulations.
For an example, refer to RLS for Data Security (Fine-Grained Access Control).
Designing multi-tenant applications
In multi-tenant applications such as typical Software-as-a-Service (SaaS) deployments, isolating data between tenants within shared tables is a requirement. Row-level Security (RLS) provides a database-level mechanism for enforcing this isolation. SaaS providers can utilize RLS policies to ensure tenants can only access their own data, eliminating the need for complex and potentially insecure application-layer filtering logic based on tenant IDs.
For an example, refer to RLS for Multi-Tenant Isolation.
How to use row-level security
At a high level, the steps for using row-level security (RLS) are as follows:
- Choose which schema objects need row-level security. You can re-use existing schemas, or create new ones and insert data. (
CREATE TABLE
,INSERT
) - Create roles & grant access to schema objects by those roles. (
CREATE ROLE
,GRANT
) - Enable row-level security on the schema objects. (
ALTER TABLE ... ENABLE ROW LEVEL SECURITY
) - Define row-level security policies on the schema objects which are assigned to specific roles. (
CREATE POLICY
)
For demonstrations showing how to use row-level security, refer to the examples.
How row-level security policies are evaluated
Policies function as filters or constraints applied automatically by CockroachDB during query execution. They are based on boolean expressions evaluated in the context of the current user, session properties, and the row data itself.
When row-level security is enabled on a table:
- Existing SQL privileges still determine if a user can access the table at all (e.g.,
SELECT
,INSERT
). - Row-level security policies determine which rows within the table are accessible or modifiable for specific commands.
Further details about RLS evaluation include:
- All policies apply to a specific set of roles. For a policy to be applicable, it must match at least one of the roles assigned to it. If the policy is associated with the
PUBLIC
role, it applies to all roles. - If RLS is enabled but no policies apply to a given combination of user and SQL statement, access is denied by default.
- Permissive policies are combined using
OR
logic, while restrictive policies are combined usingAND
logic. The overall policy enforcement is determined by evaluating a logical expression of the form:(permissive policies) AND (restrictive policies)
. In order for reads or writes to succeed, there must be at least one permissive policy for the user's role. - The
USING
clause ofCREATE POLICY
filters rows during reads; theWITH CHECK
clause validates writes, and defaults toUSING
if absent.
Considerations
Performance
Complex policy expressions evaluated per-row can impact query performance. To limit the performance impacts of row-level security, optimize your policy expressions and consider indexing relevant columns.
Security privileges
Policy expressions execute with the privileges of the user invoking the query, unless functions marked SECURITY DEFINER
are used.
Functions marked SECURITY DEFINER
should only be used with extreme caution to ensure expressions do not have unintended side effects.
Limitations
SQL language features that bypass row-level security
The following SQL language features bypass row-level security:
- Foreign keys (including cascades)
- Primary key constraints
- Unique constraints
TRUNCATE
Change data capture (CDC)
CDC messages that are emitted from a table will not be filtered using RLS policies. Furthermore, CDC queries are not supported on tables using RLS, and will fail with the error message: CDC queries are not supported on tables with row-level security enabled
.
Backup and restore
Backup and restore functionality does not take RLS policies into account.
Logical data replication (LDR) and Physical cluster replication (PCR)
Logical Data Replication (LDR) and Physical Cluster Replication (PCR) do not take RLS policies into account.
LDR's limitations with respect to schema changes also apply to RLS, since RLS policies amount to a schema change.
If you use PCR, the target cluster will have all RLS policies applied to the data because PCR performs byte-for-byte replication.
Views
When views are accessed, RLS policies on any underlying tables are applied. Policies can only be defined directly on tables, not views.
Views will only show rows that the current user has access to on the table that the view is referencing.
Examples
Create a policy
Refer to CREATE POLICY
.
Alter a policy
Refer to ALTER POLICY
.
Drop a policy
Refer to DROP POLICY
.
Enable or disable row-level security
For examples, refer to:
RLS for data security (fine-grained access control)
In a fine-grained access control scenario, you will want to restrict access to specific rows within a table based on user roles, attributes, or relationships defined within the data itself. This goes beyond table-level GRANT
permissions. Common examples include restricting access to salary information, personal data, or region-specific records.
For example, imagine an employees
table containing sensitive salary information. You want to enforce the following rules:
- Employees can view their own record.
- Managers can view the records of their direct reports.
- Members of the
hr_department
role can view all records.
Set up fine-grained access control schema
Define the hr_department
role and employees
table, add some data, and grant basic table access:
-- Create a role needed for the example policies.
-- Note: In a real scenario, manage roles appropriately.
-- This may require admin privileges not available to all users.
CREATE ROLE hr_department;
CREATE ROLE manager;
CREATE ROLE employee;
-- Create roles for employees.
CREATE ROLE alice;
CREATE ROLE bob;
CREATE ROLE carol;
CREATE ROLE david;
CREATE ROLE edward;
GRANT hr_department to edward;
GRANT manager to alice, carol;
GRANT employee to alice, bob, carol, david, edward;
-- Assume roles 'hr_department' and potentially others exist.
-- Usernames are assumed to match the 'username' column for simplicity.
CREATE TABLE employees (
id SERIAL PRIMARY KEY,
username TEXT UNIQUE NOT NULL,
full_name TEXT NOT NULL,
manager_username TEXT,
salary NUMERIC(10, 2) NOT NULL
);
-- Sample Data
INSERT INTO employees (username, full_name, manager_username, salary) VALUES
('alice', 'Alice Smith', NULL, 120000),
('bob', 'Bob Jones', 'alice', 80000),
('carol', 'Carol White', 'alice', 85000),
('david', 'David Green', 'carol', 70000),
('edward', 'Edward Scissorhands', 'alice', 70000);
-- Grant basic table access (RLS will refine row access)
GRANT SELECT, INSERT, UPDATE, DELETE ON employees TO hr_department;
GRANT SELECT ON employees TO manager;
GRANT SELECT ON employees TO employee;
Enable row-level security for fine-grained access control
Enable row-level security using the ALTER TABLE ... ENABLE ROW LEVEL SECURITY
statement. Optionally, you may want to ensure that the table owner is also subject to RLS using ALTER TABLE ... FORCE ROW LEVEL SECURITY
.
ALTER TABLE employees ENABLE ROW LEVEL SECURITY;
-- Optional: Ensure owner is also subject to policies if needed
-- ALTER TABLE employees FORCE ROW LEVEL SECURITY;
Define row-level security policies for fine-grained access control
Define RLS policies on the table. The following policy allows HR full access to the table:
CREATE POLICY hr_access ON employees
FOR ALL -- Applies to SELECT, INSERT, UPDATE, DELETE
TO hr_department
USING (true) -- No row restriction for HR
WITH CHECK (true); -- No check restriction for HR
The following policy allows employees to view their own record.
CREATE POLICY self_access ON employees
AS PERMISSIVE -- Combine with other permissive policies (like manager access)
FOR SELECT
TO employee
USING (username = CURRENT_USER);
The following policy allows managers to view their direct reports' records. This requires a way to look up the manager's username. In this example, we use the CURRENT_USER
special form of the function with the same name.
CREATE POLICY manager_access ON employees
AS PERMISSIVE
FOR SELECT -- Only for viewing
TO manager
USING (manager_username = CURRENT_USER);
-- No WITH CHECK needed as it's SELECT-only
Verify fine-grained access control policies
To verify that the RLS settings are working as expected, execute the statements in this section.
The following statement is executed by user alice
(the manager), and returns: Alice, Bob, Carol, and Edward, but not David, since he works for Carol.
This is expected behavior due to Alice's manager
role having self_access
or manager_access
policies.
SET ROLE alice;
SELECT * FROM employees;
RESET ROLE;
id | username | full_name | manager_username | salary
----------------------+----------+---------------------+------------------+------------
1068380269155778561 | alice | Alice Smith | NULL | 120000.00
1068380269155844097 | bob | Bob Jones | alice | 80000.00
1068380269155876865 | carol | Carol White | alice | 85000.00
1068380269155942401 | edward | Edward Scissorhands | alice | 70000.00
The following statement is executed by user bob
(an employee), and returns only Bob's information.
This is expected behavior due to Bob's employee
role only having the self_access
policy.
SET ROLE bob;
SELECT * FROM employees;
RESET ROLE;
id | username | full_name | manager_username | salary
----------------------+----------+-----------+------------------+-----------
1068380269155844097 | bob | Bob Jones | alice | 80000.00
(1 row)
The following statement is executed by user carol
(a manager), and returns: Carol, David.
This is expected behavior due to Carol's manager
role having self_access
or manager_access
policies.
SET ROLE carol;
SELECT * FROM employees;
RESET ROLE;
id | username | full_name | manager_username | salary
----------------------+----------+-------------+------------------+-----------
1068380269155876865 | carol | Carol White | alice | 85000.00
1068380269155909633 | david | David Green | carol | 70000.00
(2 rows)
The following statement is executed by a user edward
belonging to hr_department
, and returns all rows.
This is expected behavior due to Edward's hr_department
role having hr_access
or self_access
policies.
SET ROLE edward;
SELECT * FROM employees;
RESET ROLE;
id | username | full_name | manager_username | salary
----------------------+----------+---------------------+------------------+------------
1068380269155778561 | alice | Alice Smith | NULL | 120000.00
1068380269155844097 | bob | Bob Jones | alice | 80000.00
1068380269155876865 | carol | Carol White | alice | 85000.00
1068380269155909633 | david | David Green | carol | 70000.00
1068380269155942401 | edward | Edward Scissorhands | alice | 70000.00
(5 rows)
RLS for multi-tenant isolation
Multi-tenant isolation is used to enforce strict data separation between different tenants (customers, organizations) sharing the same database infrastructure and schema. Each tenant must only be able to see and modify their own data. This is a critical requirement for Software-as-a-Service (SaaS) applications.
For example, imagine a SaaS application serving multiple tenants, with all invoice data residing in a single invoices
table. This table is distinguished by a tenant_id
column. The application ensures that each user session is associated with a specific tenant_id
.
Create multi-tenant schema
Create the schema and index for the tenants
and invoices
tables. Next, add an index on tenant_id
for increased lookup performance.
CREATE TABLE IF NOT EXISTS tenants (
tenant_id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
name TEXT NOT NULL UNIQUE
);
CREATE TABLE IF NOT EXISTS invoices (
invoice_id SERIAL PRIMARY KEY,
tenant_id UUID NOT NULL REFERENCES tenants(tenant_id),
customer_name TEXT NOT NULL,
amount NUMERIC(12, 2) NOT NULL,
created_at TIMESTAMPTZ DEFAULT now()
);
CREATE INDEX idx_invoices_tenant_id ON invoices(tenant_id);
Populate the schema with data:
-- Insert the known tenants first to satisfy FK constraints
INSERT INTO tenants (tenant_id, name) VALUES
('ad7b4529-f5d6-4d0e-8b0f-91af455a70e5', 'Default Tenant'),
('9607a12c-3c2f-407b-ae3c-af903542395b', 'Tenant A Inc.'),
('8177c2fc-3b55-47b7-bf84-38bd3a3e9c0a', 'Tenant B Solutions');
-- Insert some additional dummy tenants
INSERT INTO tenants (name) VALUES
('Example Corp'),
('Global Widgets Ltd.');
-- Now, populate the invoices table
-- Use the known tenant UUIDs and some generated ones (assuming default gen_random_uuid works or select from tenants)
-- Invoice for Tenant A
INSERT INTO invoices (tenant_id, customer_name, amount) VALUES
('9607a12c-3c2f-407b-ae3c-af903542395b', 'Customer One', 1500.75);
-- Invoice for Tenant B
INSERT INTO invoices (tenant_id, customer_name, amount) VALUES
('8177c2fc-3b55-47b7-bf84-38bd3a3e9c0a', 'Customer Two', 899.00);
-- Another invoice for Tenant A
INSERT INTO invoices (tenant_id, customer_name, amount) VALUES
('9607a12c-3c2f-407b-ae3c-af903542395b', 'Customer Three', 210.50);
-- Invoice for Example Corp (assuming its UUID was generated)
INSERT INTO invoices (tenant_id, customer_name, amount)
SELECT tenant_id, 'Customer Four', 5000.00
FROM tenants WHERE name = 'Example Corp';
-- Invoice for Global Widgets Ltd. (assuming its UUID was generated)
INSERT INTO invoices (tenant_id, customer_name, amount)
SELECT tenant_id, 'Customer Five', 120.99
FROM tenants WHERE name = 'Global Widgets Ltd.';
-- Yet another invoice for Tenant B
INSERT INTO invoices (tenant_id, customer_name, amount) VALUES
('8177c2fc-3b55-47b7-bf84-38bd3a3e9c0a', 'Customer Six', 345.67);
Define user roles for app developer
The following statements create an app developer role, and grant it permissions.
CREATE ROLE app_dev;
GRANT SELECT ON tenants TO app_dev;
GRANT SELECT, INSERT, UPDATE, DELETE ON invoices TO app_dev;
Define how the application sets the tenant ID for the session
Each application will need to set the tenant context for the session. In this example, you will use the application_name
session variable to pass in a tenant ID that will later be extracted from the variable.
Specifically, the UUID following the period in application_name
is the tenant ID. We will use the current_setting()
function in our RLS policies to extract the ID.
For multi-tenancy to work correctly, this setting must be reliably managed by the application layer and passed in the connection string.
SET application_name = 'my_cool_app.9607a12c-3c2f-407b-ae3c-af903542395b';
Enable row-level security for multi-tenant isolation
To enable row-level security for the invoices
table, issue the following statements.
For multi-tenant isolation to work properly in this example, you must also FORCE ROW LEVEL SECURITY
so that the policies also apply to the table owner.
ALTER TABLE invoices ENABLE ROW LEVEL SECURITY, FORCE ROW LEVEL SECURITY;
Define tenant isolation policies
The following policy enforces tenant isolation for all operations.
CREATE POLICY tenant_isolation_permissive ON invoices
AS PERMISSIVE
FOR ALL
TO public
USING (tenant_id = COALESCE(
-- Attempt to extract UUID after the '.' in application_name
-- Handle cases where setting is missing or improperly formatted
NULLIF(split_part(current_setting('application_name', true), '.', 2), '')::UUID,
-- If no tenant ID is successfully extracted, use the Default Tenant ID
'ad7b4529-f5d6-4d0e-8b0f-91af455a70e5'
)
);
CREATE POLICY tenant_isolation ON invoices
AS RESTRICTIVE
FOR ALL
TO app_dev
USING (tenant_id = split_part(current_setting('application_name', true),'.',2)::UUID) -- Filter rows on SELECT/UPDATE/DELETE
WITH CHECK (tenant_id = split_part(current_setting('application_name', true),'.',2)::UUID); -- Enforce tenant_id on INSERT/UPDATE
Explanation of policy:
AS PERMISSIVE
: Necessary because you need at least one permissive policy. The permissive policy above has logic to show results for a default tenant ID if theapplication_name
is omitted or improperly formatted.AS RESTRICTIVE
: Makes the policy mandatory. If other policies exist, they must also pass. For simple tenant isolation, this is often the safest default. The restrictive policy above applies to theapp_dev
role, so that anyone assigned to theapp_dev
role must use the correctly formattedapplication_name
, and is not allowed to fallback to the default tenant ID.FOR ALL
: Covers all data modification and retrieval.TO PUBLIC
: Applies the policy broadly. Roles should primarily manage table-level access usingGRANT
, while this policy handles row-level visibility.USING
: Ensures queries only see rows matching the session's tenant ID, which is passed in using theapplication_name
session variable and extracted using thesplit_part
function.WITH CHECK
: Prevents users fromINSERT
ing rows with a tenant ID column different from their session's calculated tenant ID, orUPDATE
ing a row to change itstenant_id
column across tenant boundaries. Without this, a user could potentially insert data into another tenant's space. In this case, theWITH CHECK
expression could have been omitted; it is only necessary if it's different than theUSING
expression, or if it applies to a command that doesn't do reads (e.g., forINSERT
).
Verify multi-tenant isolation policies
To verify that the RLS settings are working as expected, execute the statements in this section. They use two tenants with the following IDs:
- Tenant A, which has ID
9607a12c-3c2f-407b-ae3c-af903542395b
. - Tenant B, which has ID
8177c2fc-3b55-47b7-bf84-38bd3a3e9c0a
.
First, become the app_dev
role which the policy applies to.
SET ROLE app_dev;
Tenant A should see only those columns in invoices
which have a tenant_id
column matching its ID.
SET application_name = 'my_cool_app.9607a12c-3c2f-407b-ae3c-af903542395b';
SELECT * FROM invoices;
Tenant B should see only those columns in invoices
which have a tenant_id
column matching its ID.
SET application_name = 'my_cool_app.8177c2fc-3b55-47b7-bf84-38bd3a3e9c0a';
SELECT * FROM invoices;
Tenant A should not be able to make changes to the invoice
table for rows that don't have a tenant_id
column matching its ID.
SET application_name = 'my_cool_app.9607a12c-3c2f-407b-ae3c-af903542395b';
INSERT INTO invoices (tenant_id, customer_name, amount) VALUES ('8177c2fc-3b55-47b7-bf84-38bd3a3e9c0a'::UUID, 'Customer Three', 123.45);
The preceding statement fails because it violates the policy's WITH CHECK
constraint, and the following error is signaled:
ERROR: new row violates row-level security policy for table "invoices"
Tenant A should be able to modify rows in the invoice
table that have a tenant_id
column matching its ID.
SET application_name = 'my_cool_app.9607a12c-3c2f-407b-ae3c-af903542395b';
INSERT INTO invoices (tenant_id, customer_name, amount) VALUES ('9607a12c-3c2f-407b-ae3c-af903542395b'::UUID, 'Customer Three', 678.90);
The preceding statement succeeds.
INSERT 0 1
Video demo: Row-level Security
For a demo showing how to combine row-level security with Multi-region SQL to constrain access to specific rows based on a user's geographic region, play the following video: