If the connection is a pool connection it will be released back into the pool for future use. If the connection isn't a pool connection then the connection to the PBMS server will be immediately closed.
Although connections are automatically closed at the end of the script's execution it is recommended that you always call pbms_close() after you are through using a connection so that it's resources can be freed immediately and in the case of pool connections the connection can be released back t the pool where it will be available for the next pbms_connect() or pbms_pconnect() call.
Note: pbms_close() will not close persistent connections created by pbms_pconnect() .