assert_failure Assert Failure — SQLSTATE P0004

A PL/pgSQL ASSERT condition evaluated to false.

• The error is written to the server log and returned to the client carrying SQLSTATE P0004.
• Any driver (libpq, JDBC, psycopg, npgsql, pgx) surfaces this code in its error object so you can branch on it programmatically.
• PL/pgSQL can trap it by name: EXCEPTION WHEN assert_failure THEN.

Severity: ERROR  |  PostgreSQL versions: 12, 13, 14, 15, 16, 17

Reproduce with the exact statement and read the full message in the server log (raise log_min_messages / set log_min_error_statement for more context).

An ASSERT caught an invalid internal state — usually a real bug.

Steps to resolve P0004:

1. Fix the underlying logic that violated the assertion.
2. Disable asserts in production via plpgsql.check_asserts only if that is intentional.

Reference: PostgreSQL error codes — Class P0 (PL/pgSQL Error).