A custom sweep retrieves instances of a target class and processes them with a user-implemented action handler.
Like a system sweep, a custom sweep operates as a background task on the server and passes retrieved instances to an action handler for processing. In both cases, a filter condition can be applied to the sweep to narrow the scope of the retrieved instances. However, a system sweep performs an action that is built into the server, whereas a custom sweep performs an action that is added to the server by an administrator.