Auto Loader offers two modes for ingesting new files from cloud object storage:

1. Directory listing: Auto Loader detects new files by listing the input directory, employing a directory polling approach.
2. File notification: Auto Loader can automatically configure a notification and queue service that subscribes to file events from the input directory.

The file notification mode is more efficient, enabling real-time data processing as it arrives in cloud object storage.

For more details, refer to: Choosing between file notification and directory listing modes | Databricks on AWS