insufficient_privilege permission denied for sequence … — 42501

Symptoms

A role lacked the privilege needed to use a sequence (e.g. nextval/currval). PostgreSQL raises SQLSTATE 42501 (insufficient_privilege).

• Missing USAGE/SELECT/UPDATE on the sequence.
• Common when a serial/identity insert needs the sequence.
• Sequence privileges are separate from table privileges.

What the server log shows

ERROR:  permission denied for sequence orders_id_seq

Why PostgreSQL raises this — what the manual says

the GRANT reference (Compatibility):

“The sequence privileges SELECT and UPDATE are PostgreSQL extensions.”

Sequence operations require specific privileges (USAGE/SELECT/UPDATE) on the sequence object. Without them — even when inserting into a table whose default uses the sequence — PostgreSQL reports 42501.

Common causes

• The role lacks USAGE/UPDATE on the sequence backing a serial column.
• Granting table privileges but not sequence privileges.
• A new role not covered by default privileges.

How to fix it

1. Grant access: GRANT USAGE ON SEQUENCE orders_id_seq TO app_user;.
2. Set default privileges so future sequences are usable by the role.
3. Prefer identity columns (PG10+) which simplify sequence privileges.

Related & next steps

• SQLSTATE 42501 — Insufficient Privilege (full reference)
• Message: permission denied for function
• Glossary: Sequence

Reference: PostgreSQL 18 — GRANT.