Postgresql - unable to drop database because of some auto connections to DB

Question

Whenever I try to drop database I get:

ERROR:  database "pilot" is being accessed by other users
DETAIL:  There is 1 other session using the database.

When I use:

SELECT pg_terminate_backend(pg_stat_activity.pid)
FROM pg_stat_activity
WHERE pg_stat_activity.datname = 'TARGET_DB';

I terminated the connection from that DB, but if I try to drop database after that somehow someone automatically connects to that database and gives this error. What could be doing that? No one uses this database, except me.

Answer 1

You can prevent future connections:

REVOKE CONNECT ON DATABASE thedb FROM public;

(and possibly other users/roles; see \l+ in psql)

You can then terminate all connections to this db except your own:

SELECT pid, pg_terminate_backend(pid) 
FROM pg_stat_activity 
WHERE datname = current_database() AND pid <> pg_backend_pid();

On older versions pid was called procpid so you'll have to deal with that.

Since you've revoked CONNECT rights, whatever was trying to auto-connect should no longer be able to do so.

You'll now be able to drop the DB.

This won't work if you're using superuser connections for normal operations, but if you're doing that you need to fix that problem first.

---

After you're done dropping the database, if you create the database again, you can execute below command to restore the access

GRANT CONNECT ON DATABASE thedb TO public;