Are there any Buddhist suttas in the scriptures about retaining memory?

As I understand, the early Buddhist teachings were transmitted orally and memorized by monks and they were written down only much later. It must have been tremendous feet of human memory to retain so many of the sutras in the Tipitaka. I want to ask, are there any teachings, maybe in the ***vinaya pitaka***, which will help a monk increase his or her memory in order to remember the sutras.