How to Resolve 'Access Denied' Errors in PostgreSQL

How do I fix "access denied" errors in PostgreSQL?

Fixing “access denied” means granting the right privileges, roles, or connection permissions to the user who is being blocked in PostgreSQL.

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Description

Example H2

Example H3

Why does PostgreSQL say “access denied”?

PostgreSQL returns an “access denied” (permission denied) error when the current role lacks privileges to connect to a database, read a table, or execute a function. The fix is always to grant the missing privilege or change the role’s search path.

How do I check the missing privilege quickly?

Run SELECT * FROM pg_catalog.pg_default_acl; or psql -E to see the exact GRANT the server expected. The error message often ends with “for relation tablename,” giving you the object needing a GRANT.

What GRANT syntax should I use?

Use GRANT [privilege_list] ON [object] TO [role];. Replace privilege_list with SELECT, INSERT, UPDATE, etc., and object with table, schema, or database.

How do I fix connection-level access denied?

Create a role with a password and grant it CONNECT on the target database. Also edit pg_hba.conf to allow the client’s host and authentication method (typically md5 or scram-sha-256).

Step-by-step

1- CREATE ROLE app_user LOGIN PASSWORD 'strongpwd';
2- GRANT CONNECT ON DATABASE ecommerce TO app_user;
3- Edit pg_hba.conf: host ecommerce app_user 0.0.0.0/0 scram-sha-256
4- Reload pg_ctl reload or SELECT pg_reload_conf();

How do I fix table-level access denied?

Grant the exact privilege on the table or, better, on the entire schema so future tables inherit the rule.

GRANT SELECT, INSERT ON ALL TABLES IN SCHEMA public TO app_user;

Can I give temporary full access for debugging?

Yes, assign the built-in role pg_read_all_data or pg_write_all_data then revoke it once debugging finishes.

Is there a risk in granting too much?

Yes. Over-granting breaks the principle of least privilege. Limit permissions to only what the application needs and audit pg_roles regularly.

Why How to Resolve 'Access Denied' Errors in PostgreSQL is important

How to Resolve 'Access Denied' Errors in PostgreSQL Example Usage


-- App user places a new order after privileges are fixed
INSERT INTO Orders (customer_id, order_date, total_amount)
VALUES (5, CURRENT_DATE, 129.99);

-- Analyst reads order data without errors
SELECT o.id, c.name, o.total_amount
FROM Orders o
JOIN Customers c ON c.id = o.customer_id
WHERE o.order_date = CURRENT_DATE;

How to Resolve 'Access Denied' Errors in PostgreSQL Syntax


-- Create a login role for an ecommerce app
CREATE ROLE app_user LOGIN PASSWORD 'strongpwd';

-- Allow connections to the ecommerce database
GRANT CONNECT ON DATABASE ecommerce TO app_user;

-- Grant schema-wide privileges so new tables inherit them
GRANT USAGE ON SCHEMA public TO app_user;
GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO app_user;
GRANT USAGE, SELECT ON ALL SEQUENCES IN SCHEMA public TO app_user;

-- Example: fine-grained order access
GRANT SELECT ON Orders, OrderItems TO app_analyst;

Common Mistakes

Granting on the wrong database object. Users often run GRANT on the database when the error is for a table. Always match the object in the error message (relation, sequence, schema, or database).
Editing pg_hba.conf but forgetting to reload the config. Changes take effect only after running SELECT pg_reload_conf() or restarting the server.