object_in_use Object In Use — SQLSTATE 55006

The operation cannot proceed because the object is currently in use.

• The error is written to the server log and returned to the client carrying SQLSTATE 55006.
• 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 object_in_use 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).

Another session holds the object — for example dropping a database with active connections.

Steps to resolve 55006:

1. Disconnect users of the object: SELECT pg_terminate_backend(pid) FROM pg_stat_activity WHERE datname = 'db' AND pid pg_backend_pid();.
2. Retry once the object is free; schedule during a maintenance window.

Reference: PostgreSQL error codes — Class 55 (Object Not In Prerequisite State).