[Postgres] drop database , but the database is being accessed by other users

1.

postgres=# drop database otmstest;
ERROR:  database "otmstest" is being accessed by other users
DETAIL:  There are 9 other sessions using the database.
postgres=# SELECT
postgres-#     pg_terminate_backend(pid)
postgres-# FROM
postgres-#     pg_stat_activity
postgres-# WHERE
postgres-#     -- don't kill my own connection!
postgres-#     pid <> pg_backend_pid()
postgres-#     -- don't kill the connections to other databases
postgres-#     AND datname = 'database_name'
postgres-#     ;

2. maybe restart postgres .

sudo service postgresql restart