By default, the loader will regularly issue a commit with each 64MB batch of data is loaded into the database.
You can change the commit interval by using the ‘C’ switch. When a commit interval is specified, regular commits will happen during the file load each with a commit size no less than the commit interval specified. Note that the commit switch does not guarantee to commit precise numbers of records at a time.
You can also defer any commits until the end of the file using the ‘C’ switch.