Before performing a takeover operation, you should perform the following actions.
At a minimum, shut down all update-capable processes on the primary database (when possible, in the negotiated case).
Stopping update processing ensures that there are no active transactions when the takeover is initiated, as a database quiet point on the primary database is a prerequisite to the takeover action. If updating processes and users are left operating on the primary database, they will encounter exceptions if they attempt to update non-environmental objects when the primary database has converted to a secondary database.
If the reason for the takeover is to perform scheduled maintenance on the primary host, it is preferable to shut down all nodes connected to the primary host before initiating the takeover.
You do not have to stop inquiry processes on the secondary database that is to assume the primary role. When the takeover is accomplished and the secondary database has changed roles to a primary database, the inquiry processes can begin to perform updating transactions without having to restart that node.