Quiescing Database

Quiescing a Database

Users will remain logged in, and they can continue to execute their requests that are in progress, while the database is in the quiesced state. The database, however, will block all new transactional requests except those made by the users SYS and SYSTEM (not DBA grantees).

ALTER SYSTEM QUIESCE RESTRICTED;
ALTER SYSTEM UNQUIESCE;
SELECT instance_name, status, shutdown_pending, active_state FROM v$instance;