object_in_use database “…” is being accessed by other users — 55006

Symptoms

A DROP DATABASE failed because other sessions are still connected to that database. PostgreSQL raises SQLSTATE 55006 (object_in_use).

• Other users are connected to the target database.
• A database with active sessions can’t be dropped.
• Common when an app pool still holds connections.

What the server log shows

ERROR:  database "appdb" is being accessed by other users
DETAIL:  There are 4 other sessions using the database.

Why PostgreSQL raises this — what the manual says

the DROP DATABASE reference (Description):

“Also, if anyone else is connected to the target database, this command will fail unless you use the FORCE option described below.”

A database in use by active sessions is “in use” and cannot be removed safely. PostgreSQL blocks the drop with 55006 until those sessions disconnect (or are terminated).

Common causes

• Application connection pools still attached to the database.
• Idle sessions left open.
• Monitoring/admin tools connected to it.

How to fix it

1. Terminate connections, then drop: DROP DATABASE appdb WITH (FORCE); (PG13+).
2. Manually terminate sessions via pg_terminate_backend() filtered by datname.
3. Stop the application/pool before dropping the database.

Diagnostic query

SELECT pid, usename, application_name, state FROM pg_stat_activity WHERE datname = 'appdb';

Identify and stop the listed sessions before dropping (or use WITH FORCE).

Related & next steps

• SQLSTATE 55006 — Object In Use (full reference)
• Message: cannot drop the currently open database
• Glossary: Database

Reference: PostgreSQL 18 — DROP DATABASE.