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PostgreSQL 0LP01 Error: Causes and Solutions Complete Guide

#postgres #database #dba #sql

PostgreSQL Error 0LP01: invalid grant operation

PostgreSQL error 0LP01 invalid grant operation occurs when a GRANT or REVOKE statement is executed in a way that violates the database's permission rules. This typically happens when the grantor lacks the necessary GRANT OPTION, an incompatible privilege is assigned to an object type, or the target role does not exist. Understanding this error is essential for maintaining a secure and well-structured permission model in production environments.

Top 3 Causes and SQL Examples

1. Grantor Does Not Hold GRANT OPTION

To delegate a privilege to another user, the grantor must possess that privilege WITH GRANT OPTION. Without it, any attempt to pass the privilege downstream will trigger 0LP01.

-- Check if a user has GRANT OPTION on a table
SELECT grantor, grantee, privilege_type, is_grantable
FROM information_schema.role_table_grants
WHERE table_name = 'orders'
  AND table_schema = 'public';

-- Grant with GRANT OPTION (must be done by owner or superuser)
GRANT SELECT ON TABLE public.orders TO manager_role WITH GRANT OPTION;

-- Now manager_role can delegate to others
SET ROLE manager_role;
GRANT SELECT ON TABLE public.orders TO reporting_user;
RESET ROLE;
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2. Privilege Type Incompatible with Object Type

Each PostgreSQL object type supports only a specific set of privileges. Attempting to grant an unsupported privilege — such as INSERT on a sequence or EXECUTE on a table — will cause this error.

-- WRONG: Granting INSERT on a sequence (causes 0LP01)
-- GRANT INSERT ON SEQUENCE public.order_id_seq TO app_user;

-- CORRECT: Valid privileges for a sequence
GRANT USAGE, SELECT, UPDATE ON SEQUENCE public.order_id_seq TO app_user;

-- CORRECT: Valid privileges for a schema
GRANT USAGE, CREATE ON SCHEMA public TO app_user;

-- CORRECT: Valid privileges for a function
GRANT EXECUTE ON FUNCTION public.calculate_total(integer) TO app_user;
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3. Target Role Does Not Exist

If the role specified in a GRANT statement has not yet been created, the operation will fail. This is common in migration scripts where object creation and privilege assignment are not properly ordered.

-- Check if a role exists before granting
SELECT rolname FROM pg_roles WHERE rolname = 'app_service';

-- Safely create role if it doesn't exist, then grant
DO $$
BEGIN
    IF NOT EXISTS (
        SELECT FROM pg_roles WHERE rolname = 'app_service'
    ) THEN
        CREATE ROLE app_service WITH LOGIN PASSWORD 'str0ng_p@ss';
    END IF;
END
$$;

-- Grant privileges after confirming role existence
GRANT SELECT, INSERT, UPDATE ON ALL TABLES IN SCHEMA public TO app_service;
GRANT USAGE ON ALL SEQUENCES IN SCHEMA public TO app_service;
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Quick Fix Solutions 

-- Verify current privileges on an object
\dp public.your_table

-- Identify all privileges granted by a specific role
SELECT grantee, table_name, privilege_type, is_grantable
FROM information_schema.role_table_grants
WHERE grantor = 'your_role_name';

-- Revoke and re-grant cleanly with proper options
REVOKE ALL PRIVILEGES ON TABLE public.your_table FROM problem_user;
GRANT SELECT, INSERT ON TABLE public.your_table TO problem_user;
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Prevention Tips

Use role hierarchies instead of direct user grants. Define group roles like readonly_role and readwrite_role, assign privileges to those roles, and add users as members. This eliminates most ad-hoc grant errors and simplifies permission management significantly.

CREATE ROLE readonly_role;
CREATE ROLE readwrite_role;

GRANT SELECT ON ALL TABLES IN SCHEMA public TO readonly_role;
GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO readwrite_role;

-- Assign users to roles, not objects directly
GRANT readonly_role TO analyst_user;
GRANT readwrite_role TO app_user;

-- Auto-apply to future objects
ALTER DEFAULT PRIVILEGES IN SCHEMA public
    GRANT SELECT ON TABLES TO readonly_role;
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Implement privilege auditing as a routine. Run periodic queries against information_schema and pg_catalog to review all active grants. Log every GRANT and REVOKE operation through a change management process to catch unauthorized or incorrect privilege assignments before they become security incidents.

Related Errors

  • 42501 (insufficient_privilege) — The most common companion error; raised when a role attempts an action it has no privilege for.
  • 0L000 (invalid_grantor) — Raised when the grantor itself is invalid or does not meet requirements for the grant operation.
  • 28000 (invalid_authorization_specification) — Related to authentication and role specification issues at the connection level.

📖 Want a more detailed guide?
Check out the full in-depth version (Korean) on oraerror.com — includes detailed analysis, additional SQL examples, and prevention tips.

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