How to CURRENT_USER in PostgreSQL

Galaxy Glossary

How do I use the CURRENT_USER function in PostgreSQL?

CURRENT_USER returns the name of the role executing the current transaction.

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Description

Example H2

Example H3

What does CURRENT_USER return?

CURRENT_USER returns the role name that owns the current database session.It is evaluated once per transaction and is not affected by SET ROLE.

When should I use CURRENT_USER?

Use it in audit tables, row-level security (RLS) policies, or dynamic SQL that must adapt permissions to the executing role.

How do I call CURRENT_USER in a SELECT?

Place CURRENT_USER wherever an expression is valid: SELECT CURRENT_USER; or add it as a column in a larger query.

Can I alias CURRENT_USER?

Yes.SELECT CURRENT_USER AS session_user; is common when logging user activity.

How does CURRENT_USER differ from SESSION_USER?

SESSION_USER returns the role that authenticated the connection.CURRENT_USER switches when you execute SET ROLE; SESSION_USER does not.

Example: stamping orders with the session role

Insert the current role into an audit trail: INSERT INTO order_audit(order_id, changed_by) VALUES (42, CURRENT_USER);

Example: row-level security policy

CREATE POLICY customer_is_owner ON Orders USING (customer_id = (SELECT id FROM Customers WHERE email = CURRENT_USER));

Best practices

1) Cast CURRENT_USER to text if concatenating. 2) Avoid relying on it for security without RLS or GRANTs. 3) Log it early in triggers for traceability.

Why How to CURRENT_USER in PostgreSQL is important

How to CURRENT_USER in PostgreSQL Example Usage


-- Who is running this?
SELECT CURRENT_USER AS running_role;

-- Audit an order update
UPDATE Orders SET total_amount = 129.99 WHERE id = 101;
-- Trigger logs: (order_id=101, changed_by='dev_user', changed_at=NOW())

How to CURRENT_USER in PostgreSQL Syntax


-- Basic usage
SELECT CURRENT_USER;

-- Alias for readability
SELECT CURRENT_USER AS session_role;

-- Use in INSERT (ecommerce)
INSERT INTO Orders(id, customer_id, order_date, total_amount, created_by)
VALUES (101, 7, NOW(), 149.99, CURRENT_USER);

-- Use in a function
CREATE OR REPLACE FUNCTION log_order_update() RETURNS trigger AS $$
BEGIN
  INSERT INTO order_audit(order_id, changed_by, changed_at)
  VALUES (NEW.id, CURRENT_USER, NOW());
  RETURN NEW;
END;$$ LANGUAGE plpgsql;

Common Mistakes

Using CURRENT_USER for authentication checks only. Why wrong: it changes after SET ROLE, so it may not reflect the original login. Fix: use SESSION_USER when you need the login role.
Assuming CURRENT_USER updates inside one transaction after SET ROLE. Why wrong: CURRENT_USER is set at transaction start. Fix: COMMIT or ROLLBACK, then SET ROLE and start a new transaction.