Note: The following description applies both to Postgres-XC and PostgreSQL if not described explicitly.
DROP DATABASE drops a database. It removes the catalog entries for the database and deletes the directory containing the data. It can only be executed by the database owner. Also, it cannot be executed while you or anyone else are connected to the target database. (Connect to postgres or any other database to issue this command.)
DROP DATABASE cannot be undone. Use it with care!
Note: The following description applies only to Postgres-XC
If there's any live connection to any of the template database in coordinator or datanode, you will have an error message. In this case, you should clean these connections using CLEAN CONNECITON statement.
Do not throw an error if the database does not exist. A notice is issued in this case.
The name of the database to remove.
DROP DATABASE cannot be executed inside a transaction block.
This command cannot be executed while connected to the target database. Thus, it might be more convenient to use the program dropdb instead, which is a wrapper around this command.